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O R I G I N A L A R T I C L E

A multicentre, randomised controlled clinical trial
evaluating the effects of a novel autologous, heterogeneous
skin construct in the treatment of Wagner one diabetic foot
ulcers: Interim analysis

David G. Armstrong1 | Dennis P. Orgill2 | Robert Galiano3 | Paul M. Glat4 |

Lawrence Didomenico5 | Alexander Reyzelman6 | Robert Snyder7 |

William W. Li8 | Marissa Carter9 | Charles M. Zelen10

1Department of Surgery, University of
Southern California, Keck School of
Medicine, Los Angeles, California
2Division of Plastic Surgery, Brigham and
Women’s Hospital, Boston, Massachusetts
3Division of Plastic Surgery, Northwestern
University Feinberg School of Medicine,
Chicago, Illinois
4Drexel University, Philadelphia,
Pennsylvania
5Lower Extremity Institute of Research
and Therapy, Youngstown, Ohio
6Center for Clinical Research, San
Francisco, California
7Clinical Research Barry University SPM,
Brand Research Center, Barry University,
Miami, Florida
8The Angiogenesis Foundation,
Cambridge, Massachusetts
9Strategic Solutions, Bozeman, Montana
10Department of Medical Education, The
Professional Education and Research
Institute (PERI), Roanoke, Virginia

Correspondence
Charles M. Zelen, DPM, Department of
Medical Education, The Professional
Education and Research Institute,
222 Walnut Ave., Roanoke, VA 24016.
Email: [email protected]

Funding information
Polarity TE, Grant/Award Number: 002

Abstract

We desired to carefully evaluate a novel autologous heterogeneous skin con-

struct in a prospective randomised clinical trial comparing this to a standard-

of-care treatment in diabetic foot ulcers (DFUs). This study reports the interim

analysis after the first half of the subjects have been analysed. Fifty patients

(25 per group) with Wagner 1 ulcers were enrolled at 13 wound centres in the

United States. Twenty-three subjects underwent the autologous heterogeneous

skin construct harvest and application procedure once; two subjects required

two applications due to loss of the first application. The primary endpoint was

the proportion of wounds closed at 12 weeks. There were significantly more

wounds closed in the treatment group (18/25; 72%) vs controls (8/25; 32%) at

12 weeks. The treatment group achieved significantly greater percent area

reduction compared to the control group at every prespecified timepoint of

4, 6, 8, and 12 weeks. Thirty-eight adverse events occurred in 11 subjects (44%)

in the treatment group vs 48 in 14 controls (56%), 6 of which required study

removal. In the treatment group, there were no serious adverse events related

to the index ulcer. Two adverse events (index ulcer cellulitis and bleeding)

were possibly related to the autologous heterogeneous skin construct. Data

from this planned interim analysis support that application of autologous het-

erogeneous skin construct may be potentially effective therapy for DFUs and

provide supportive data to complete the planned study.

K E Y W O R D S

biological products, diabetic foot, randomised controlled trial, ulcer, wound healing

Received: 17 February 2021 Revised: 28 March 2021 Accepted: 31 March 2021

DOI: 10.1111/iwj.13598

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any

medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

© 2021 The Authors. International Wound Journal published by Medicalhelplines.com Inc (3M) and John Wiley & Sons Ltd.

64 Int Wound J. 2022;19:64–75.wileyonlinelibrary.com/journal/iwj

1 | INTRODUCTION

Diabetic foot ulcers (DFUs) cost Medicare $6.2–18.7 bil-
lion each year and have a devastating annual impact on
the economy of United States, with an annual burden of
over $50 billion.1,2 Approximately 1.5 million Americans
have DFUs, which contribute to 130 000 annual lower-
extremity amputations.3,4 A real-world analysis of 62 964
DFUs registered in the US Wound Registry found that
their healing rate at 12 weeks was only 30.5%.5 A meta-
analysis of DFUs treated in trials with standard of care
revealed a 12-week closure rate of 24%.6 Biological skin
substitutes are commonly used as adjunctive therapy to
improve wound closure.7,8 However, most products are
quite costly and require multiple applications. Split-
thickness skin grafting (STSG) can contribute new
healthy tissue to the wound bed but has a failure rate of
approximately 30% when applied to DFUs as a conse-
quence of poor graft take by the chronic wound bed, the
presence of diabetes, vascular insufficiency, other com-
orbidities, and/or bacterial contamination.9-14 As many
DFUs are treated in the outpatient setting, another disad-
vantage of skin grafting is that it involves a surgical pro-
cedure in the operating room.

A novel autologous heterogeneous skin construct
(AHSC) created from a small harvest of full thickness,
healthy skin may be safe and effective as adjunctive ther-
apy in treating complex and refractory wounds.15-24 AHSC
is composed of small multicellular segments and contains
the endogenous regenerative cellular populations of
healthy skin that promote wound closure, so that a single
application can regenerate full-thickness, functionally
polarised skin on the wound bed.20-25 The manufacturing
process of the AHSC retains the endogenous regenerative
cellular populations associated with wound healing pre-
sent within hair follicles, glands, and the interfollicular
epidermis, facilitating engraftment optimisation and
wound closure.24 AHSC is not cultured ex vivo, but rather
it is expeditiously returned to the provider to be adminis-
tered topically over a clean, debrided, viable wound bed
and covered with common nonadherent, nonabsorbent
dressings in the outpatient setting. The AHSC conforms
nicely to the wound and over days forms small skin islands
that expand and coalesce across the entire wound bed to
close the wound, rather than initiating epithelialisation
solely from the wound margin.20,21 In a pilot study of
11 patients with DFUs extending up to the tendon, bone,
or capsule, 10 patients closed within 8 weeks of a single
application of AHSC, with the mean percent area reduc-
tion (PAR) for all wounds at 4 weeks at 83%.24 A larger,
controlled trial was needed to confirm these initial findings
in DFUs. A planned interim analysis of the first 50 of the
100 patients of a randomised controlled trial (RCT) was

performed to compare the effects of AHSC to standard of
care in the treatment of Wagner 1 DFUs.

2 | METHODS

2.1 | Study design and population

This was a planned interim analysis of the first 50 patients
of a prospective, multicentre, RCT evaluating wound clo-
sure rates of DFUs treated in an outpatient setting. Thir-
teen wound care centres in the United States participated
in this study. The null hypothesis was the proportion of
wounds closed at 12 weeks, after up to 12 weeks of AHSC
and standard of care or standard of care alone, would be
equal for groups 1 (AHSC + standard of care) and 2 (con-
trol). Formally, H0: I1–I2 = 0; HA: I1–I2 = D1 ≠ 0,
where I1 was the proportion of wounds closed in group
1, I2 was the same metric for group 2, D1 was the differ-
ence (I1–I2); assuming the alternative hypothesis and sta-
tistical test used was chi square/Fisher exact test. The
primary endpoint was the percentage of index ulcers
closed at 12 weeks. Complete closure was defined when
100% epithelialisation without drainage was first
observed, followed by a closure confirmation visit

Key Messages

• This interim analysis of an ongoing, random-
ised controlled trial evaluated a single applica-
tion of autologous heterogeneous skin
construct (AHSC) as adjunctive therapy to
standard of care in Wagner 1 diabetic foot
ulcers compared to standard of care alone in
50 initial subjects.

• There were significantly more wounds closed
in the AHSC group (18/25; 72%) compared to
the control group (8/25; 32%) (P = .005) and a
significantly greater percent area reduction in
the AHSC group compared to the control
group at each prespecified timepoint of
4 weeks (79% vs 24%, P = .0002), 6 weeks (83%
vs 44%, P = .004), 8 weeks (87% vs 47%,
P = .002), and 12 weeks (88% vs 50%,
P = .012), respectively.

• In the AHSC group, there were no serious
adverse events related to the index ulcer or
determined to be related to AHSC treatment.

• These data support continuation of the
planned study

ARMSTRONG ET AL. 65

2 weeks later. Secondary endpoints included the PAR at
4, 6, 8, and 12 weeks; changes in wound quality-of-life
(W-QOL short questionnaire, with each question scored
on a scale of 0 = “not at all” to 4 = “very much”);
reduced pain (based on the Visual Analogue Scale [VAS],
with 0 = no pain and 10 = worst possible pain); improve-
ments in peripheral neuropathy by Semmes Weinstein
monofilament test; and incidence of adverse events (AEs)
and complications.

The sample size was determined to be 102 (51 in
each group) to achieve 89% power to detect a difference
between the group proportions of 0.3. The proportion in
the AHSC group was assumed to be 0.3 under the null
hypothesis and 0.6 under the alternative hypothesis.
The proportion in the control group was 0.3. The test
statistic used was the two-sided Z test with pooled vari-
ance. The significance level of the test was targeted at
0.05. The significance level actually achieved by this
design was 0.05. Unblinded interim analysis was per-
formed after 50 subjects completed the study in order to
assess subject outcomes between the groups and to
recalculate the sample size for the primary endpoint.
This study was conducted according to the principles
expressed in the Declaration of Helsinki, and the Insti-
tutional Review Board Advarra (Columbia, MD)
approved the study protocol. The study protocol was
registered on clinicaltrials.gov (NCT03881254).

Adult patients with a Wagner 1 DFU that did not
involve the tendon, muscle, or bone, provided that it was
below the aspect of the medial malleolus, were screened
for study participation. Table 1 details complete inclusion
and exclusion criteria. Eligible patients provided their
written informed consent and were enrolled into the
study. During their first screening visit, their demo-
graphics and medical history were recorded; a complete
physical examination was performed; laboratory tests
were taken; the index ulcer was assessed for infection
and pain; adequate perfusion was confirmed; Semmes
Weinstein monofilament test for peripheral neuropathy
was performed; subjects answered the W-QOL short
questionnaire; sharp debridement of the index ulcer was
performed as needed; the wounds were dressed with
standard of care; and offloading was initiated.

Two weeks after the initial screening visit, subjects
returned to undergo the same assessments to check for
any changes in their health, ulcer healing status, and eli-
gibility. Randomisation occurred if the ulcer did not
change in size greater than 30% and still met eligibility.
The Organisation1 (City2, State2) used a block size of
10 for randomisation (5 sheets of paper with a standard-
of-care assignment and 5 with an AHSC assignment).
Each sheet was inserted into an opaque envelope that
was sealed. The study coordinator shuffled the envelopes,

while under observation by the principal investigator and
staff. After repeating the process 10 times, the envelopes
were sent to the study sites, ensuring that site investiga-
tors were blinded to the randomisation method and treat-
ment assignment. The site investigators enrolled the
subjects into the study and were aware of the study group
following randomisation.

2.2 | AHSC preparation, application,
and follow-up

Following randomisation, standard of care was applied
to both groups, and the AHSC group underwent the
skin harvest procedure. Standard of care included
offloading of the DFU (CAM boots or total contact
casting, if the subject’s foot was too large for a CAM
boot, or per the provider’s discretion), appropriate
sharp or surgical debridement, collagen alginate and
appropriate wound care covering, including 4 × 4
gauze pads, foam, and a multilayer compression ban-
daging system comprised a soft roll layer, an elastic
layer, and a cohesive bandage layer (Dyna-Flex, KCI,
St. Paul, MN).In the AHSC group, a 1 × 2 cm full-
thickness harvest of healthy skin was excised from the
index limb of each subject using sterile technique and
local. The provider sutured closed the harvest site. The
harvest was shipped overnight to a Food and Drug
Administration–registered biomedical manufacturing
facility (PolarityTE, Salt Lake City, UT) and used to
manufacture the AHSC (Product, Organisation3). The
AHSC was returned to the provider within 48 hours of
tissue harvest and applied to the wound within 4 days
after the harvesting procedure. The AHSC was shipped
and stored at 4�C before application.

On the day of the application procedure, the wound
was cleaned and sharply debrided, if required. The AHSC
was spread evenly across the wound bed. Next, the
wound was dressed with a silicone dressing covered by
an absorbent foam dressing (DermaFoam, DermaRite
Industries, North Bergen, NJ). A three-layer compression
bolster was then applied. Dressings were changed
weekly, and wounds continued to be offloaded. At the
third follow-up visit, a nonadherent contact layer
(Adaptic Touch, KCI) replaced the silicone dressing.
After the AHSC was applied and the wound was
addressed, a time-out procedure undertaken by the on-
site study team confirmed the application of the subject’s
own harvested construct to the index ulcer.

Subjects in both groups had weekly follow-up visits
and dressing changes with standard of care for up to
12 weeks. At each visit, wound sites (including the har-
vest sites in the AHSC group) were assessed for healing

66 ARMSTRONG ET AL.

status, pain, and infection; the index ulcer was measured
and assessed for graft take; and AEs were reported. A
licensed provider who did not treat the index ulcer first
performed an initial, blinded wound closure assessment
of the wound in-person. Once considered healed by the
blinded investigator, the wound images were forwarded
to a group of university plastic surgeon adjudicators who
determined if the wound was healed within 24 hours of
receiving the photographs. If two-thirds of the adjudica-
tors agreed that the wound had closed, then the subject
returned for a closure confirmation visit 2 weeks later. At
the end-of-study visit, W-QOL was also assessed, and a
Semmes-Weinstein monofilament test was administered
for peripheral neuropathy.

2.3 | Data collection and analysis

Data were stored in an Excel database. The statistical
analysis was performed using PASW 27 (IBM, Chicago,
IL). Blinded, interim analysis was first performed, and
coding for treatment was then applied to the analysis
involving comparison of groups.

The intent-to-treat (ITT) and safety populations com-
prised randomised subjects who received at least 1 treat-
ment. All analyses used the ITT approach. The last
observation carried forward principle that was used with
regard to missing area data at study visits. Study variables
were summarised as means and SDs for continuous vari-
ables as well as medians for nonnormal data. Categorical

TABLE 1 Patient inclusion and exclusion criteria

Inclusion criteria

• At least 18 years old
• Presence of a Wagner 1 DFU that did not extend through the dermis or subcutaneous tissue and did not involve the tendon, muscle,

or bone, provided that it was below the aspect of the medial malleolus
• If two or more Wagner 1 DFUs were present, then the index ulcer was the largest ulcer and the only one evaluated in the study. Any

other ulceration must have been 2 cm distant from the index ulcer.

• Index ulcer was present for at least 4 weeks
• Index ulcer was a minimum of 1.0 cm2 and a maximum of 25 cm2 at screening visit and did not reduce/increase in area by 30% or

more after 14 days of standard of care prior to first treatment visit

• Index ulcer had been offloaded for ≥14 days prior to randomisation

• Index ulcer had a clean granular base, was free of necrotic debris, and appeared to healthy, vascularised tissue at time of AHSC
placement

• Affected foot had adequate circulation as documented by a dorsal transcutaneous oxygen measurement or a skin perfusion pressure
measurement of ≥30 mmHg, or an ankle brachial index of ≥0.7 and ≤1.2, or arterial Doppler with a minimum of biphasic flow within
3 months of treatment

• Women of childbearing age were willing to use contraception during the study and undergo pregnancy tests

• Patient understood and was willing to participate in the study, could comply with the weekly visits and follow-up, and provided
written informed consent.

Exclusion criteria

• Active osteomyelitis, cellulitis, soft tissue infection, or active Charcot’s arthropathy of the affected foot involving or near the index
ulcer site, or on the same limb as the index ulcer within 30 days prior to randomisation

• Index ulcer was suspicious of cancer

• History of radiation at the index ulcer site

• History of >2 weeks treatment with immunosuppressants (including systemic corticosteroids), cytotoxic chemotherapy, or application
of topical steroids to the index ulcer surface within 1 month prior to screening, or who were anticipated to require such medications
during the study

• Evidence of unstable HIV, hepatitis B, or hepatitis C
• On an investigational drug or therapeutic device within 30 days of screening
• Index ulcer was previously treated or needed to be treated with any prohibited therapies such as chlorhexidine or collagenase
• Presence of any condition which seriously compromised the patient’s ability to complete the study or had a known history of poor

adherence with medical treatment
• In the opinion of the investigator, the patient was noncompliance with offloading or index ulcer dressing prior to randomisation
• Pregnant or breastfeeding
• Presence of diabetes with poor metabolic control as documented with an HbA1c ≥12.0 within 30 days of randomisation
• Presence of end-stage renal disease as evidenced by serum creatinine of greater than 3.0 mg/dL within 120 days of randomisation

Abbreviations: AHSC, autologous homologous skin construct; DFU, diabetic foot ulcer.

ARMSTRONG ET AL. 67

variables were presented as counts and proportions or
percentages. Statistical testing between groups at baseline
was carried out to examine the success of randomisation.
For categorical variables, chi-squared or Fisher exact tests
were performed, and for continuous variables indepen-
dent t tests or Mann-Whitney tests were used (depending
on variable normality) to test for statistical differences.

The PAR for the index ulcer at X weeks was calcu-
lated as ([AI – AXW]/AI)×100, where AI is the area of the
index wound at randomisation and AXW is the area at
X weeks. When AHSC was applied twice, area data by
week was based on data associated with the first AHSC
application, followed by the second AHSC application,
and then follow-up.

The primary endpoint (proportion of wounds closed
at 12 weeks) between study groups was analysed using
chi square.

Secondary endpoints between study groups were
analysed by chi-squared or Fisher exact tests for categori-
cal variables, while independent t tests or Mann–Whitney
tests were used to test for statistical differences for contin-
uous variables depending on outcome variable normality,
which was examined using the Wilks-Shapiro test. The
exception was PAR at 2, 4, 6, 8, and 12 weeks, which was
analysed using general linear mixed modelling (GLMM)
with repeated measures (no random effects). Two-sided
P values <.05 were considered significant.

Summary statistics were used as inputs to calculate
the conditional statistical power for all endpoints based
on a final N of 100 using PASS13 software (NCSS, LLC,
Kaysville, UT).

All AEs were categorised as “serious” or “not serious”
and assessed for severity (mild, moderate, severe, or life-
threatening) and relationship to the AHSC product and
harvesting and placement procedures (not related, possi-
bly related, probably related, or definitely related).

3 | RESULTS

Study recruitment began on April 2, 2019, and all sub-
jects exited the trial by June 20, 2020. This interim analy-
sis covers the 79 patients screened for eligibility and the
50 subjects (63%) who were enrolled (Figure 1). One sub-
ject (4%) was withdrawn from the AHSC group due to
development of respiratory illness and sepsis, whereas
6 subjects (24%) were withdrawn in the control group
due to 1 subject being incarcerated and 5 having AEs
occur that required study removal (Figure 1). Table 2
summarises patient demographics and medical history
with no significant differences between groups. Three
subjects in the AHSC and 6 in the control group had
missing HbA1c data. The index ulcer was treated with

multiple therapies prior to study enrolment, with similar
treatments applied to both groups, except for antibiotics,
which were administered significantly more to the con-
trol group (P = .023) (Table 2).

All 25 subjects in the AHSC group underwent the
AHSC harvest and application procedure, but 2 subjects
required a second AHSC application due to loss of the
first application requiring a second tissue harvest. The
proximal medial calf was the most common harvest site
(17/27, 63%). Upper medial thigh and proximal lateral leg
were harvested for the remainder of the cases. Nine
AHSC constructs (33%) were applied 2 days after harvest,
17 (63%) after 3 days, and 1 (4%) after 5 days.

3.1 | Closure rates

There were statistically significantly more wounds closed
in the AHSC group (18/25; 72%) compared to the control
group (8/25; 32%) at 12 weeks (P = .005). Closure rates
through week 12 are shown in Figure 2. Based on these
data and using the 2-side Z test with pooled variance, the
projected statistical power for 100 subjects was 98.8%.

Table 3 and Figure 3 summarise the PAR data
through 12 weeks. The GLMM model would not always
converge when a random intercept model was incorpo-
rated into a factorial fixed effects model with 4 levels
(PAR at the 4 time periods) no matter what covariance
matrix was selected. Removing the random effects and
using the simpler model with an unstructured correla-
tions covariance matrix resulted in a worse fit but similar
to other covariance matrices (−2LL or BIC); however, for
treatment, a significant effect was observed (P = .013).
Based on these data, the projected statistical power for
100 subjects was 90+%. Representative images of wound
closure are shown in Figure 4.

All harvest sites remained closed following primary
closure and fully healed within 12 weeks except for in
1 subject who was withdrawn from the trial before
healing could be confirmed.

3.2 | Safety analysis

There were 86 AEs allocated to 25 subjects. The AHSC
group had 38 AEs allocated to 11 subjects (44%), while
the control group had 48 AEs allocated to 14 subjects
(56%). The overall AE rate was 1.5 for the AHSC group
and 1.9 for the control group.

There were 13 SAEs, 7 in the AHSC group and 6 in
the Control group. In the AHSC group, 1 subject had
3 SAEs (congestive heart failure, dyspnea episode that
was a symptom of SARS-CoV-2 infection, and his index

68 ARMSTRONG ET AL.

Assessed for eligibility (n = 79)

Excluded (n = 29)a

♦ Ineligible ulcer area (22.4%)
♦ Ulcer area increased/decreased by

≥30% 2 weeks after screening (19.0%)

♦ Declined to participate (10.3%)
♦ Treatment site had soft tissue infection

or gangrene (12.1%)

♦ Noncompliance with offloading or
dressing (6.9%)

♦ Not a Wagner 1 DFU (6.4%)
♦ HbA1c ≥12.0 (3.4%)
♦ End stage renal disease (3.4%)
♦ COVID-19 concerns (3.4%)
♦ Hospitalized with COVID-19 (3.4%)
♦ Unable to measure ulcer area (3.4%)
♦ Subject did not show up for visit (3.4%)
♦ Ineligible wound area (22.4%)
♦ Prohibited therapies applied to index ulcer

(1.1%)

♦ Osteomyelitis/bone infection, cellulitis, active
Charcot’s arthropathy of the index limb (1.1%)

Analysed (n = 25)

Lost to follow-up (n = 0)

Withdrawn (n = 1)

Allocated to AHSC intervention (n = 25)

♦ Received allocated intervention (n = 25)

Lost to follow-up (n = 0)

Withdrawn (n = 6)

♦ Incarcerated (n = 1)
♦ Adverse Events (n = 5)
♦ Osteomyelitis and a non-STEMI (n = 1)
♦ Tunneling of study wound (n = 1)
♦ Secondary ulcer, prescribed antibiotics,

and major protocol deviation (n = 1)

♦ Died after sepsis with possible pneumonia
and acute cerebrovascular accident (n = 1)

♦ Multiple fractures after vehicle crash (n = 1)

Allocated to Standard of Care (n = 25)

♦ Received allocated intervention (n = 25)

Analysed (n = 25)

Allocation

Analysis

Follow-Up

Randomized (n = 50)

Enrolment

FIGURE 1 Legend on next page.

ARMSTRONG ET AL. 69

wound required cauterisation following admission for his
congestive heart failure and during the admission, his
wound was debrided against protocol by the non-trail
site-admitting service, while the patient was on anti-
coagulation), while another subject had 2 SAEs (sepsis,
related to a hepatitis A infection, and cellulitis of the
right leg, which was not related to the index ulcer). Two
other subjects had 1 SAE each: an upper gastrointestinal
bleed and an acute kidney injury. In the control group,
1 subject had 4 SAEs over a 3-week period, beginning
with the development of left foot cellulitis related to the
index ulcer, followed by acute osteomyelitis, which
required surgery; severe sepsis occurred after the surgical
procedure, but it quickly resolved. A separate SAE also
occurred in a control group subject during this time
period (non–ST-segment elevation myocardial infarc-
tion). Another control group subject developed a soft tis-
sue infection related to the index ulcer, which was
treated with sharp debridement and antibiotics and
resolved after 7 weeks.

In the AHSC group, there were no product-related
SAEs. There were two AEs that were possibly related
to the treatment of the index ulcer: 1 infection of the
study right heel DFU and a bleeding episode of the
study ulcer located on the plantar aspect of the 5th
metatarsal head, right foot. Only 2 AEs (pain and cel-
lulitis) occurred in the harvest site, both in the AHSC
group. There were 7 index ulcer infections (including
cellulitis) in the control group compared to 1 in the
AHSC group. There were 4 non-index ulcer infections
in both groups. The AHSC group had 7 other complica-
tions reported, including 1 for the index ulcer, while
the Control group had 17 other complications, includ-
ing 4 for the index ulcer. There were 24 other causes of
AEs in the AHSC group versus 20 in the Control
Group.

3.3 | Other secondary endpoints

The mean (SD) difference in the W-QOL scores between
week 1 and week 12 visits was 0.1 (0.8) in the AHSC
group vs 0.6 (1.2) in the control group (P = .09).

The mean (SD) difference in pain scores between
week 1 and week 12 visits was 0.7 (1.6) in the AHSC
group and 0.5 (1.6) in the control group (P = .48).

The mean (SD) difference in Semmes-Weinstein
scores between week 1 and week 12 visits was 0.1 (1.4) in

the AHSC group and 0.4 (2) in the control
group (P = .16).

4 | DISCUSSION

A traditional method of tissue reconstruction for Wagner
1 ulcers is a skin graft once the wound has been cleaned
and granulating.20 However, a skin graft requires techni-
cally demanding surgical procedure with careful postop-
erative care, which is not easily available in many wound
care centres. It is further complicated because neuropa-
thy increased the risk of infection, endothelial dysfunc-
tion, and overall higher graft failure rate compared to
other wound types and locations..9-14,26,27 There are many
investigators developing biological ulcer products with
the goal of creating an ideal cost effective wound dressing
that when applied to wounds will assist with healing
without the complexities of surgical intervention.26,28 In
a small pilot study, AHSC applied just once to DFUs in
the outpatient setting was able to close 10/11 (91%) of
index ulcers by 12 weeks.24 In our current study, we
analysed the outcome data of the initial 50 patients as
part of a planned interim analysis of a larger, ongoing
RCT. These data support that adjunctive AHSC appears
to facilitate greater DFUs closure compared to standard
of care alone. The AHSC 12-week closure rates were sig-
nificantly superior to the controls (72% vs 32%, P = .005)
and allow us to project statistical power for 100 subjects
in this ongoing trial at 99%. The AHSC 12-week DFU clo-
sure rate of 72% in this interim analysis is a stark contrast
to the mean closure rate reported in an analysis of
26 DFU RCTs, whereby only 38% of wounds healed at
12 weeks.5 In our study, 92% of subjects required only
1 application of AHSC. Additionally, all harvest sites
remained closed following primary closure at the time of
harvest and the harvest procedure was tolerated well by
all participants. The occurrence of AEs and SAEs was
similar between the AHSC and control groups, and only
2 AEs were possibly related to the study product. Nota-
bly, in the AHSC group, there were no SAEs related to
the index ulcer, whereas 2 subjects in the control group
had 4 SAEs related to the index ulcer, including 1 subject
that developed cellulitis followed by acute osteomyelitis
requiring surgical incision and drainage. Statistical signif-
icance between groups for AEs and SAEs was not
included in the interim analysis predefined statistical
analysis plan, but the occurrence of more index ulcer-

FIGURE 1 Patient flow diagram. The superscript letter “a” indicates that when multiple exclusion criteria applied, a weighted figure
was applied so that percentages for each criterion added up to 100%. AHSC, autologous homologous skin construct, DFU, diabetic foot ulcer;

non-STEMI, non–ST-segment elevation myocardial infarction

70 ARMSTRONG ET AL.

TABLE 2 Patient demographics and medical history

Variable AHSC group (n = 25) Control group (n = 25) P

Patient age (years) 61.6 (10.3) 59.3 (13.5) .51

BMI 32.3 (7.6) 33.4 (7.5) .59

Sex

Male 18 (72) 17 (68) .76

Female 7 (28) 8 (32)

No. of comorbidities 9.6 (3.3) 10.8 (6.2) .40

Creatinine 1.4 (0.6) 1.3 (0.5) .37

HbA1c

Baseline 7.1 (1.4) 7.7 (1.7) .16

End of study 7.1 (1.6)a 8.0 (1.3)b .059

Wound area (cm2) 4.3 (4.2); median: 3.6; IQR: 3.2 3.3 (4.3); median: 1.8; IQR: 1.4 .19

Wound age (weeks) 25.3 (31.4); median: 15.3; IQR: 19 22.1 (22.6); median: 14.0; IQR: 20 .57

DFU location

Plantar 21 (84) 21 (84) 1.00

Dorsal 4 (16) 4 (16)

DFU location

Toe 4 (16) 5 (20)

Forefoot 10 (40) 13 (52) .16

Midfoot 9 (38) 2 (8)

Heel 2 (8) 4 (16)

Ankle 0 (0) 1 (4)

No. of debridements prior to enrolment 9.0 (3.8); median: 9; IQR: 6 10.6 (4); median: 10; IQR: 8 .17

Frequency of comorbidities

Hypertension 23 (92) 22 (88) .64

Peripheral arterial/vascular disease 3 (12) 4 (16) 1.00

Heart disease (any type) 3 (12) 6 (24) .46

Gastroesophageal reflux disease 6 (24) 3 (12) .46

Hyperlipidaemia 15 (60) 14 (56) .77

Renal disease 3 (12) 3 (12) 1.00

Venous insufficiency 3 (12) 1 (4) .61

Prior lower extremity amputation (any kind) 10 (40) 10 (40) 1.00

Mental disorder (any) 7(28) 10 (40) .37

Treatments up to 1 year prior

Debridements 14 (56) 16 (64) .56

Wraps or offloading 12 (48) 10 (40) .57

Negative pressure wound therapy 0 (0) 2 (8) .49

Cellular and/or tissue-based product 1 (4) 2 (8) .55

Collagen or oxidised regenerated cellulose 8 (320 6 (24) .53

Antibacterial dressing 4 (16) 3 (12) .68

Nonactive dressing 8 (32) 14 (56) .087

Antibiotics (any route) 1 (4) 8 (32) .023

Note: Continuous variables are reported as means (SD) and categorical variables as counts (percentage).
Abbreviations: AHSC, autologous homologous skin construct; BMI, body mass index; DFU, diabetic foot ulcer; IQR, interquartile range.
an = 22.
bn = 19.

ARMSTRONG ET AL. 71

related SAEs and index ulcer infections in the control
group suggests that earlier wound closure and a higher
rate of wound closure with AHSC adjunctive treatment
may avoid wound-related complications.

The manufacturing process of the AHSC retains the
endogenous regenerative cellular populations associated
with wound healing present within hair follicles, glands,
and the interfollicular epidermis, facilitating engraftment
optimisation and wound closure.24 The resulting

FIGURE 2 Weekly closure rates.
AHSC, autologous homologous skin

construct

TABLE 3 Mean (SD) percentage area reduction at weeks 4, 6,
8, and 12

Week AHSC group Control group

4 78.6 (35.6) 24.0 (106.5)

6 83.2 (40.9) 43.8 (102)

8 86.6 (39.6) 47.2 (89.9)

12 88.2 (39.1) 49.6 (101.4)

FIGURE 3 Weekly percentage area
reduction values. AHSC, autologous

homologous skin construct

72 ARMSTRONG ET AL.

construct has a high surface area-to-volume ratio, facili-
tating cellular sustenance from plasmatic imbibition in
the DFU wound bed during the first 48 hours prior to
inosculation and vascularisation.24,29,30 Consequently, a
single application of AHSC can quickly regenerate
healthy tissue and close DFUs, which has significant cost
implications (to be further explored in the final trial
analysis).

There were no significant differences in W-QOL or the
Semmes-Weinstein test between groups. This is notable as
patients were required to undergo a small tissue harvest
for the AHSC treatment. The harvest site procedure did
not significantly negatively impact their W-QOL scores,
which may have been balanced by faster wound closure
with AHSC treatment. The lack of significant difference in
the Semmes-Weinstein test may be due to the prevalence
and severity of neuropathy present in both patient groups
that cannot be corrected with topical treatments alone.

The results of this interim analysis are limited by the
ongoing nature of the trial. However, the purpose of this
interim analysis was to determine conditional statistical
power for all study endpoints. A further study limitation is
that there was no follow-up period after 12 weeks or fol-
lowing wound closure beyond 2 weeks. This RCT is also

limited by its lack of blinding, which, given the interven-
tion, was not possible. For blinding to have occurred, all
patients would have had to undergo the harvest site proce-
dure, which would not be ethically justified in the control
group. However, wound closure was assessed in person by
nontreating blinded study personnel and further confirmed
by a blinded adjudication panel of three plastic surgeons
using high-resolution digital photography.

This interim analysis of data from 50 patients enrolled
in a larger, ongoing RCT demonstrated that a single, topi-
cal application of the AHSC facilitated DFU closure. The
results of this analysis confirm our previous power analy-
sis and are encouraging to complete the planned study.

ACKNOWLEDGEMENT
PolarityTE provided a grant to complete this clinical trial.

CONFLICT OF INTEREST
This study was funded through a research grant from Pol-
arityTE; provided to the Professional Education and
Research Institute (PERI), which Charles M Zelen, DPM,
is medical director. David Armstrong, DPM, MD, PhD,
received research funds from PERI to serve as Principal
Investigator for this trial and to design and administrate

FIGURE 4 Representative images of
AHSC-treated patients, at the time of

randomisation (baseline), AHSC

deployment, during follow-up (interim

closure), and at closure confirmation

visit. AHSC, autologous homologous skin

construct

ARMSTRONG ET AL. 73

the trial and also assist with the writing and review of
the manuscript. Dennis Orgill, MD, PhD, received
research funds to serve as a validating/adjudicating
plastic surgeon to review study photos and assist with
the writing and review of the manuscript. Robert
Galiano, MD, received research funds to serve as a vali-
dating/adjudicating plastic surgeon to review study
photos and assist with the writing and review of the
manuscript. Paul Glat, MD, received research funds to
serve as a validating/adjudicating plastic surgeon to
review study photos and assist with the writing and
review of the manuscript. Lawrence Didomenico, DPM,
received research funds and served a site investigator
for this trial and assisted with the writing and review of
the manuscript. Alexander Reyzelman, DPM, received
research funds and served a site investigator for this
trial and assisted with the writing and review of the
manuscript. Robert Snyder, DPM, received research
funds and served a site investigator for this trial and
assisted with the writing and review of the manuscript.
Marissa Carter, PhD, received research funds to provide
the statistical analysis plan and provide the statistical
analysis for this trial and assist with writing of the
result section of the manuscript. William W Li, MD,
received research funds to serve as the medical monitor
and assisted with the writing and review of the manu-
script. Charles M. Zelen, DPM, is the medical director
of the PERI and his company received research funds
to administrate the clinical trial and write the paper for
publication. There are no other conflicts of interest with
any of the authors in relationship to this study or with
regard to PolarityTE. IRB conflict of interest statements
are on file with PERI.

DATA AVAILABILITY STATEMENT
The data that support the findings of this study are avail-
able on request from the corresponding author. The data
are not publicly available due to privacy or ethical
restrictions.

ORCID
Charles M. Zelen https://orcid.org/0000-0001-5682-
7056

REFERENCES
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Suppl 1:S31-S44.

8. Santema TB, Poyck PPC, Ubbink DT. Skin grafting and tissue
replacement for treating foot ulcers in people with diabetes.
Cochrane Database Syst Rev. 2016;2:CD011255.

9. Ramanujam CL, Han D, Fowler S, Kilpadi K, Zgonis T. Impact
of diabetes and comorbidities on split-thickness skin grafts for
foot wounds. J Am Podiatr Med Assoc. 2013;103:223-232.

10. Donegan RJ, Schmidt BM, Blume PA. An overview of factors
maximizing successful split-thickness skin grafting in diabetic
wounds. Diabet Foot Ankle. 2014;5:24769.

11. Ramanujam CL, Stapleton JJ, Kilpadi KL, Rodriguez RH,
Jeffries LC, Zgonis T. Split-thickness skin grafts for closure of
diabetic foot and ankle wounds: a retrospective review of
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12. Thourani VH, Ingram WL, Feliciano DV. Factors affecting suc-
cess of split-thickness skin grafts in the modern burn unit.
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13. Reddy S, El-Haddawi F, Fancourt M, et al. The incidence and
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14. Rose JF, Giovinco N, Mills JL, Najafi B, Pappalardo J,
Armstrong DG. Split-thickness skin grafting the high-risk dia-
betic foot. J Vasc Surg. 2014;59:1657-1663.

15. Armstrong DG, Orgill DP, Galiano RD, Glat PM, Carter MJ,
Zelen CM. Open-label venous leg ulcer pilot study using a
novel autolologous homologous skin construct. Plast Reconstr
Surg Glob Open. 2020;8(7):e2972.

16. Feldman MJ, McLawhorn MM, Han J, et al. A prospective,
multicenter, pilot trial of a novel homologous skin construct on
deep partial-thickness and full-thickness burns. Ann Burns Fire
Disasters. 2020;33:191-197.

17. Johnson ON, Nelson M, Estabrooke I, Sopko N, Swanson EW.
Successful treatment of war zone traumatic lower extremity
wound with exposed tendons using an autologous homologous
skin construct. Cureus. 2020;12:1-7.

18. Berg A, Kaul S, Rauscher GE, Blatt M, Cohn S. Successful full-
thickness skin regeneration using epidermal stem cells in trau-
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e10558.

19. Murphy GA, Woelfel SL, Armstrong DG. What to put on (and
what to take off) a wound: treating a chronic neuropathic ulcer
with an autologous homologous skin construct, offloading and
common sense. Oxford Med Case Rep. 2020;2020:259-263.

20. Granick MS, Baetz NW, Labroo P, Milner S, Li WW,
Sopko NA. In vivo expansion and regeneration of full-thickness
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clinical proof of concept for chronic wound healing. Int Wound
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21. Patterson CW, Stark M, Sharma S, Mundinger GS. Regenera-
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22. Isbester K, Wee C, Boas S, Sopko N, Kumar A. Regeneration of
autologous, functional, full thickness skin with minimal donor
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homologous skin constructs allow safe closure of cutaneous
wounds: a retrospective, non-controlled, multi-centered case
series. Plast Reconstr Surg Glob Open. 2020;8(5):e2840.

24. Armstrong DG, Orgill DP, Galiano R, et al. Complete wound
closure following a single topical application of a novel autolo-
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label, single-arm feasibility study in diabetic foot ulcers. Int
Wound J. 2020;17(5). https://doi.org/10.1111/iwj.13404.

25. Wong VW, Levi B, Rajadas J, Longaker MT, Gurtner GC. Stem
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26. Colazo JM, Evans BC, Farinas AF, Al-Kassis S, Duvall CL,
Thayer WP. Applied bioengineering in tissue reconstruction,
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259-290.

27. McCartan B, Dinh T. The use of split-thickness skin grafts on
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50 years of development and tissue engineering paradigms in
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29. Martinson M, Martinson N. A comparative analysis of skin
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How to cite this article: Armstrong DG,
Orgill DP, Galiano R, et al. A multicentre,
randomised controlled clinical trial evaluating the
effects of a novel autologous, heterogeneous skin
construct in the treatment of Wagner one diabetic
foot ulcers: Interim analysis. Int Wound J. 2022;19:
64–75. https://doi.org/10.1111/iwj.13598

ARMSTRONG ET AL. 75

1Seidel D, et al. BMJ Open 2020;10:e026345. doi:10.1136/bmjopen-2018-026345

Open access

Negative pressure wound therapy
compared with standard moist wound
care on diabetic foot ulcers in real- life
clinical practice: results of the
German DiaFu- RCT

Dörthe Seidel ,1 Martin Storck,2 Holger Lawall,3,4 Gernold Wozniak,5
Peter Mauckner,6 Dirk Hochlenert,7 Walter Wetzel- Roth,8 Klemens Sondern,9
Matthias Hahn,10 Gerhard Rothenaicher,11 Thomas Krönert,12 Karl Zink,13
Edmund Neugebauer14,15

To cite: Seidel D, Storck M,
Lawall H, et al. Negative
pressure wound therapy
compared with standard
moist wound care on diabetic
foot ulcers in real- life clinical
practice: results of the
German DiaFu- RCT. BMJ Open
2020;10:e026345. doi:10.1136/
bmjopen-2018-026345

► Prepublication history and
additional material for this
paper are available online. To
view these files, please visit
the journal online (http:// dx. doi.
org/ 10. 1136/ bmjopen- 2018-
026345).

Received 28 August 2018
Revised 15 January 2020
Accepted 16 January 2020

For numbered affiliations see
end of article.

Correspondence to
Ms Dörthe Seidel;
Doerthe. [email protected] uni- wh. de

Original research

© Author(s) (or their
employer(s)) 2020. Re- use
permitted under CC BY- NC. No
commercial re- use. See rights
and permissions. Published by
BMJ.

AbstrACt
Objectives The aim of the DiaFu study was to evaluate
effectiveness and safety of negative pressure wound
therapy (NPWT) in patients with diabetic foot wounds in
clinical practice.
Design In this controlled clinical superiority trial with
blinded outcome assessment patients were randomised in
a 1:1 ratio stratified by study site and ulcer severity grade
using a web- based- tool.
setting This German national study was conducted in 40
surgical and internal medicine inpatient and outpatient
facilities specialised in diabetes foot care.
Participants 368 patients were randomised and 345
participants were included in the modified intention-
to- treat (ITT) population. Adult patients suffering from
a diabetic foot ulcer at least for 4 weeks and without
contraindication for NPWT were allowed to be included.
Interventions NPWT was compared with standard moist
wound care (SMWC) according to local standards and
guidelines.
Primary and secondary outcome measures Primary
outcome was wound closure within 16 weeks. Secondary
outcomes were wound- related and treatment- related
adverse events (AEs), amputations, time until optimal
wound bed preparation, wound size and wound tissue
composition, pain and quality of life (QoL) within 16 weeks,
and recurrences and wound closure within 6 months.
results In the ITT population, neither the wound closure
rate (difference: n=4 (2.5% (95% CI−4.7% – 9.7%);
p=0.53)) nor the time to wound closure (p=0.244) was
significantly different between the treatment arms. 191
participants (NPWT 127; SMWC 64) had missing endpoint
documentations, premature therapy ends or unauthorised
treatment changes. 96 participants in the NPWT arm and
72 participants in the SMWC arm had at least one AE
(p=0.007), but only 16 AEs were related to NPWT.
Conclusions NPWT was not superior to SMWC in
diabetic foot wounds in German clinical practice. Overall,
wound closure rate was low. Documentation deficits and
deviations from treatment guidelines negatively impacted
the outcome wound closure.

trial registration numbers NCT01480362 and
DRKS00003347.

bACkgrOunD
More than 400 million people worldwide
suffer from diabetes,1 2 and about 15% of all
these patients will develop a diabetic foot ulcer

strengths and limitations of this study

► The DiaFu study included patients with diabetic foot
ulcers both with peripheral neuropathy and periph-
eral arterial occlusive disease, which corresponds
to the typical mixed patient population in real- life
clinical practice. This allows a general statement on
effectiveness and safety of negative pressure wound
therapy (NPWT) in the typical medical care situation,
but including patients with peripheral artery occlu-
sive disease and clinical signs of inflammation (sus-
pected infection) had a potentially negative effect on
the treatment outcome wound closure.

► The study does not provide any information on the
effectiveness of NPWT in specific patient groups.

► In this health services research study, hospitals
and outpatient facilities were selected by means
of a qualification checklist, and clinical investiga-
tors were obliged to provide patients with the best
clinical practice in compliance with all relevant di-
agnostic and treatment guidelines, but there was
no active monitoring of the implementation of these
guidelines.

► To ensure the best quality of local wound treatment
and to achieve optimal baseline conditions, the
study sites were trained for both NPWT and standard
moist wound care, but treatment application was at
the discretion of the clinical investigators.

► A high number of missing endpoint documentations,
premature termination of NPWT and unauthorised
therapy changes negatively impacted the treatment
outcome wound closure and may have led to bias
in the results.

2 Seidel D, et al. BMJ Open 2020;10:e026345. doi:10.1136/bmjopen-2018-026345

Open access

(DFU) during their lifetime.3 4 Approximately 50%–70%
of all lower limb amputations are due to diabetes.4 DFUs
represent complex chronic wounds with a major impact
on patients’ morbidity, mortality and quality of life
(QoL). Beside an optimal diabetes and infection control,
pressure- relieving strategies and restoring pulsatile blood
flow, effective local wound care is part of the holistic
approach necessary to optimally treat patients with DFUs.
Only a few modern moist wound dressings and topical
agents have been convincingly shown to achieve higher
wound closure rates compared with traditional wet gauze
dressings in patients with diabetic foot wounds.5 Also, for
other ulcer types, there is uncertainty as to which dress-
ings and topical agents are most effective for treatment.6
Negative pressure wound therapy (NPWT) is an inno-
vative treatment option and one of the most commonly
used and well- established technologies with the aim to
promote wound healing.7 The first use of vacuum sealing
was described in 1993 by Fleischmann et al,8 and the
commercially available product was developed later in the
1990s.9 10 Positive effects of NPWT on wound healing have
been suggested in various basic studies.10 11 At the time
of planning the DiaFu study, the clinical evidence largely
consisted of clinician perception, case reports and series,
small cohort studies and weakly powered or low- quality
randomised trials that documented broad use of NPWT
in various clinical settings and constituted a substantial
number of publications but an overall small amount of
evidence.12–15 Two randomised controlled trials (RCTs)
performed by Armstrong and Lavery16 and Blume et al17
provided a solid basis for planning a study.

In the recent years, a specific review for the use of
NPWT in diabetic foot wounds performed by Dumville et
al in 2013,18 an assessment in the home setting by Rhee
et al in 201419 and a health technology assessment partic-
ularly issued for the evaluation of NPWT for managing
DFUs20 in 2014, as well as the most recent work of Liu et al
in 201721 22 all concluded that although NPWT may have
a positive effect, the trials that have been performed have
methodological flaws and sufficient, unbiased evidence of
whether wounds heal better or worse with NPWT than
with conventional treatment is still missing.

In Germany, the issue of evidence for effectiveness
and safety of NPWT in acute and chronic wounds was
first addressed in 2002 when the German Federal Joint
Committee (German: Gemeinsamer Bundesausschuss
(G- BA)) needed to decide whether NPWT could be reim-
bursed without restrictions in outpatient care.

Finally, in 2007 taking into account all available
evidence the G- BA decided that the benefits of the treat-
ment method NPWT should be evaluated in a so- called
model project. The project was intended to include the
conduct of clinical studies for which the G- BA defined
basic requirements. This essentially concerned a study
hypothesis that supports G- BA’s overall question if
NPWT can be reimbursed in German outpatient care
without any limitation, the selection of a comparator that
represents the current treatment standard in Germany,

and implementation of all measures to ensure a sufficient
certainty of the results.

Following the announcement of the G- BA, the German
statutory health insurance funds initiated an overall
project through a European tender. The DFU was chosen
to be the representative for chronic wounds in an RCT
comparing NPWT and standard moist wound care
(SMWC) in clinical practice.

MethODs
Aim of the study
The aim of the DiaFu study was to evaluate whether the
effectiveness and safety of NPWT is superior to SMWC in
German real- life clinical practice.

study design
The DiaFu study was a multicentre, randomised controlled
clinical superiority trial with blinded assessment of wound
closure, wound size and wound tissue qualities using
photographs. This German national study was conducted
both in hospital departments and outpatient facilities
with a special qualification for diabetic foot care. Study
sites were selected based on their qualifications and
experiences using a prestudy qualification checklist and
annual quality reports of the respective institution (if
available). Study treatment was allowed to be started both
in inpatient and outpatient care and should be continued
outpatient whenever possible. More detailed information
on the study design can be found in the study protocol
publication that is available open access.23

Patient and public involvement
Patients were not involved in the design, recruitment or
conduct of the study. The results of this study will not be
disseminated directly to study participants.

Participants
Following a pragmatic approach with the aim to include
a patient population best representing real- life clinical
practice, inclusion and exclusion criteria were selected
based on manufacturers’ contraindications and US Food
and Drug Administration (FDA) warnings, the necessity
to exclude patients in need of protection and who are
unable to give their consent, and the intention to avoid
general study- related and treatment specific influences
on the results.

Adult patients (age >18 years) with at least 4- week- old
chronic DFUs corresponding to Wagner 2–4 were
screened for study participation by the local investigators.
Before inclusion, the study protocol required either a
debridement or, if necessary, an amputation of foot parts,
or a thorough wound cleansing, depending on the indi-
vidual needs of the patients. Thus, chronic diabetic foot
wounds after adequate wound pretreatment as well as
postsurgical amputation wounds below the upper ankle
joint were eligible for inclusion. The initially planned
minimum ulcer age of 6 weeks was reduced to 4 weeks

3Seidel D, et al. BMJ Open 2020;10:e026345. doi:10.1136/bmjopen-2018-026345

Open access

during the course of the study. As in clinical practice, the
assessment of patients’ suitability for a specific wound
therapy with the aim of complete wound closure and
(due to randomisation) for both study treatment arms
(NPWT and SMWC) was at the discretion of the treating
physicians (clinical investigators of the study). Particular
attention was to be paid to the diagnosis and therapy of
concomitant diseases.

Patients estimated to be at risk of non- compliance with
study requirements, with wounds with necrotic tissue
present that could not be removed by debridement
or amputation, with exposed blood vessels within or
directly surrounding the wound not possible to be suffi-
ciently covered or with an increased risk of bleeding with
haemodynamic consequences (mainly relevant for poste-
rior tibial artery dorsalis pedis artery), and outpatients
receiving anticoagulation therapy or suffering from a
high- grade impaired clotting function with a heightened
risk of bleeding with haemodynamic consequences were
excluded from the DiaFu study. The use of NPWT devices
on the study wound within 6 weeks prior to study start
represented an exclusion criterion in order to demon-
strate a clear therapeutic effect of each treatment arm.

Written informed consent was obtained from every
participant after being informed about all aspects of
the trial, and before randomisation and any trial- related
procedure. As the statutory health insurance funds
provided integrated care contracts for outpatient NPWT,
only patients who were members of a participating health
insurance fund were allowed to be enrolled.

randomisation and masking
Patients were randomly allocated to the treatment arms
in a 1:1 ratio using a computer- generated list located
on a centralised web- based tool. The randomisation list
consisted of permuted blocks of variable length which
were randomly arranged. Patients were stratified by study
site and by Wagner- Armstrong stage within each site
(<Wagner- Armstrong stage 2C and ≥Wagner- Armstrong
stage 2C). The randomisation lists were generated with
the help of a self- created Java program and integrated
into the study database. Each registered investigator
received individual access to the randomisation tool via
the study website but without knowledge of future treat-
ment assignment, which provided adequate allocation
concealment. The investigators were responsible for
adequately implementing the assigned therapy. Due to
the physical differences between the treatment regimens,
it was not possible to blind either participant or physician
to the treatment assignment. Verification of complete
wound closure was performed by independent, blinded
assessment of wound photographs. Determination of
wound size and percentage wound tissue quality was also
performed by central, blinded outcome assessors based
on the wound photographs using the Wound Healing
Analyzing Tool (W.H.A.T.). The determination of suffi-
cient wound bed conditioning and the indication for
surgical closure was carried out by the treating physician,

as in clinical practice. The treating physician was not
blinded to treatment allocation.

Procedures
Basic data were collected for all patients considered for
study participation during screening and were updated
during the randomisation visit. Patients received an exten-
sive examination of overall health status, specific diabetes
associated disorders and relevant influence factors on
wound healing during screening with an update at the
randomisation visit. Neuropathy and vascular diagnos-
tics were performed according to the German National
Health Care Guidelines for Type 2 Diabetes Foot Compli-
cations.24 After anamnesis and general diagnostics (phys-
ical examination), this care guideline recommends the
following further vascular diagnostics: ankle–arm index
(‘Ankle- Brachial- Index’) and additional assessment of the
Doppler frequency spectrum (due to the possible falsi-
fying of the results by Media sclerosis) and, if necessary,
additional hydrostatic toe pressure measurement (pole
test) or a transcutaneous oxygen measurement (tcPO

2
),

duplex sonography to determine the extent and distri-
bution pattern of a potential peripheral artery occlusive
disease (PAOD) (including the lower leg arteries if neces-
sary). In case of inconclusive findings, contrast agent-
enhanced MR angiography and intra- arterial digital
subtraction angiography were considered. No detailed
examination results of the vascular diagnostics but the
final diagnosis of PAOD and critical limb ischaemia (CLI)
were to be documented in the electronic case report form
(eCRF) by the clinical investigators. Infection diagnosis
comprised clinical evaluation and laboratory testing. In
case of suspected diabetic foot osteomyelitis, a probe to
bone test and a stepwise approach to imaging modalities
were applied in order to confirm the clinical diagnosis
and to determine the best treatment regimen for the
study participants.

Before randomisation and start of study treatment,
all patients underwent one or more of the following
no longer than 6 hours before randomisation: amputa-
tion, debridement or thorough wound cleansing. Study
therapy was allowed to be started either in- hospital or as
outpatient and was intended to be continued in outpa-
tient care whenever possible.

In the intervention arm commercially available
CE- marked NPWT devices of the manufacturers Kinetic
Concepts Incorporated (KCI) and Smith & Nephew
(S&N) were used in the discretion of the clinical inves-
tigator according to clinical routine and manufacturers’
instructions.23 Intermittent and continuous NPWT
was allowed to be used with the negative pressure to
be adapted as recommended for the dressing applied
(V.A.C.-Granufoam Black or Silver; V.A.C.-White Foam;
Renassys–F/P; Renassys–G) and adapted to the wound
needs. Recommendations for use are available on the
manufacturers’ websites. As part of the European tender
for the overall project, the German statutory health insur-
ance funds awarded lots for the provision of the medical

4 Seidel D, et al. BMJ Open 2020;10:e026345. doi:10.1136/bmjopen-2018-026345

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products by the respective manufacturers. Germany was
divided into four supply areas. During the award proce-
dure, S&N received one lot and KCI three lots. Thus,
devices and consumables of S&N were used for the north
and northern east region of Germany, and for the rest of
Germany, the therapy systems of KCI were used. Within
the study, NPWT was required to be used for wound
bed preparation in order to achieve at least 95% gran-
ulation of the wound area. After optimal preparation of
the wound, complete closure could be achieved either by
secondary intention with dressings or by surgical closure
with subsequent removal of the suture.

Control therapy was defined as any SMWC according
to local clinical standards and guidelines.25 26 Healthcare
providers were obligated to provide patients with best
practice. In the control arm, it was permitted to apply
any local wound treatment standard used in the respec-
tive study site that did not have an experimental status
or was NPWT. To ensure the best quality of local wound
treatment, the study sites were trained for both the inter-
vention arm by the manufacturers and the control arm
by the German Society for Wound Healing and Wound
Treatment, which provided parts of its curriculum and
experienced instructors.

The maximum study treatment time was 16 weeks after
randomisation. Study visits needed to be performed at
week 1, 3, 5, 12 and 16, and in the event of end of treat-
ment, hospital discharge, wound closure and for wound
closure confirmation after a minimum of 14 days. Study
participants were followed up until 6 months after rando-
misation. The initially planned follow- up period of 12
months was reduced to 6 months in the course of the
study. The amendment to the study protocol was endorsed
by the Ethics Committee and immediately communicated
to all participating study sites.

Outcomes
The primary outcome was wound closure (100% epithe-
lialisation of the wound, no drainage, no suture material
and no need for wound dressing or adjuvants) within the
maximum study treatment period of 16 weeks. Wound
closure could be achieved both by healing by secondary
intention and by delayed primary closure. Complete
closure of the wound needed to sustain for a minimum
of 14 days and to be confirmed by independent blinded
observers using wound photographs.

Secondary outcomes were wound closure after 6
months, time until optimal preparation of the wound
bed (a minimum of 95% granulation), amputations and
resections, wound size and wound tissue composition,
pain and QoL within 16 weeks, and recurrence within
6 months. The initial planned secondary endpoint time
until wound closure within 6 months was abandoned
during the course of the study. It was found that a time-
to- event survey was not possible outside the active study
treatment period. This was mostly due to the fact that after
this 16- week period, weekly study visits were no longer an

obligation, and further patient care was no longer bound
to the study site.

Minor and major amputations were assessed sepa-
rately, whereas the disarticulation at the midtarsal joint
(Chopart’s amputation) was considered still to be minor.
Wound size and wound tissue composition (percentage
of granulation tissue, fibrin and necrosis) were moni-
tored at each study visit. QoL was measured using the
questionnaire Euro Quol 5D (EQ5D) at inclusion, end
of the maximum treatment time or end of the therapy
and at the 6- month follow- up visit. At each study visit
participants were asked to provide their assessment
of wound- associated pain on a numerical rating scale
(0–10). The incidence of serious adverse events (SAEs)
within 6 months and the incidence of device- related and
treatment- related adverse events (AEs) occurring within
16 weeks or until wound closure confirmation were safety
endpoints of this trial.

statistical analysis
Sample size calculation was performed using the expected
difference between wound closure rates in both treat-
ment arms based on information extracted from previ-
ously published studies by Armstrong and Lavery16 and
Blume et al.17 We assumed a complete wound closure rate
of 45% for NPWT and 30% in the SMWC group, resulting
in a minimum difference of 15% after a treatment time of
16 weeks. Based on a type 1 error of α=0.05 and a type 2
error of β=0.2 (corresponding to a power of 80%), a total
sample size of 162 patients per group was calculated. The
computer program of Dupont and Plummer was used for
sample size calculation.27

We performed all analyses based on a modified
intention- to- treat (ITT) population that includes all
randomised participants who have a valid baseline and
at least one valid post baseline wound assessment. As a
secondary approach a per- protocol (PP) analysis was
performed excluding patients with any serious protocol
deviations, like temporary changes from SMWC to NPWT,
permanent wound treatment changes or without valid
documentation until wound closure confirmation or end
of maximum treatment time (EOMTT). Safety data are
presented on an ‘as treated’ basis. Subgroup analysis is
presented for small versus large wound subpopulations.
There was no interim analysis.

The superiority hypothesis was tested in parallel for
the wound closure rate and the time to wound closure
within 16 weeks. Incidence of complete wound closure
was analysed using Fishers’ exact test comparing the
two treatment arms. Time to complete wound closure
was compared between the two treatment arms using a
log- rank test. The method of Bonferroni- Holm was used
for adjustment of the α-error for parallel confirmatory
testing of both primary endpoints. Missing values have
been incorporated as censored values.

During study planning, the following concomitant
diseases and therapeutic measures with a possible influence
on the primary study outcome wound closure (confounders)

5Seidel D, et al. BMJ Open 2020;10:e026345. doi:10.1136/bmjopen-2018-026345

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were identified: presence of neuropathy (sensation loss
according to the Perfusion, Extent, Depth, Infection and
Sensation (PEDIS) classification system28); presence of
diabetic neuropathic osteoarthropathy (anatomical classifi-
cation according to Sanders and Frykberg29 and progression
stages according to Levin30); Wagner31 grading of the ulcer;
presence of peripheral arterial occlusive disease (Ruther-
ford classification for chronic limb ischaemia32); chronic
venous insufficiency (Widmer I–III33); presence of extreme
foot deformities and malpositions of toes, foot or the entire
limb; untreated or therapy- refractory inflammation in the
wound area; chronic anaemia; heel necrosis; presence of
a lymphedema; infection; heightened glycated haemo-
globin level; dialysis; application of hyperbaric oxygen or
normothermal therapy; application of recombinant or
autologous growth factors to the study wound; and applica-
tion of skin or dermal substitutes and with living cells that
produce growth factors. These covariates thought to influ-
ence wound closure were analysed for their effect on the
two primary endpoints. Covariates were excluded from the
analysis if the number of missing values was too high. First,
the relevant covariates were tested by means of a univariate
analysis with regard to their effect on wound closure rate
and time without consideration of the treatment arms. If
there was a significant influence, the frequency of occur-
rence in the treatment arms was analysed. Secondary,
multivariate analyses were performed for both primary
endpoints, taking into account treatment assignment and
including all relevant covariates. The multivariate analysis
of the primary endpoint wound closure rate was performed
with binary logistic regression to describe the influence of
the independent covariates (regressors) on the dependent
dichotomous variable wound closure. The multivariate
analysis of the primary endpoint time to wound closure was
performed using a ox regression model.

Safety and secondary endpoints were analysed using
conventional univariate testing.

Within an a- priori- planned subgroup analysis, the ITT
population was divided into a group of small wounds and
a group of large wounds based on the wound surface area
documented during the randomisation visit. Wounds
smaller than or equal to the total median wound surface
(483 mm²) were assigned to the subgroup ‘small wounds’.
Patients with wound surface areas larger than the median
value were assigned to the subgroup ‘large wounds’.
Since no citable scientific definition of a large wound was
available at the time of study planning and the clinical
experts involved could not make a decision, the median
of all wounds was chosen as the criterion for the division
into the two subgroups. Confirmatory analysis of primary
and secondary endpoints was repeated for the subgroups.

Missing values for the following outcome parameters
were replaced using the last observation carried forward
(LOCF) method: wound closure rate, wound size and
wound tissue quality, recurrence and amputation. The
outcome parameters time to wound closure and time until
optimal preparation of the wound bed did not require
data replacement, since missing values are included in the

analysis as right- censored values. If wound closure was not
confirmed to be closed after a minimum of 14 days, the
wound wass considered as an unsustained wound closure.
All missing QoL values (EQ5D) were replaced with the
overall QoL assessment (visual analogue scale), if available.
If there was no QoL assessment, there was no replacement.
For missing values of the demographic and baseline char-
acteristics, which are necessary for the estimation of the
regression coefficients, no replacement was performed.
IBM SPSS Statistics (V.23) was used for all analyses.

This study is registered with ClinicalTrials. gov and in
the German Clinical Trial Registry.

A data monitoring committee was formed to oversee
overall study performance and safety.

role of the funding source
Through a European tender, the study was initiated by a
consortium of 19 statutory German health insurance funds,
which provided integrated care contracts for all study partic-
ipants and for up to 7000 patients with acute and chronic
wounds in Germany, defined basic rules for study design
based on the requirements of the German authorities; and
provided a critical review of the study protocol and the final
report. The study was funded by the manufacturers KCI
(Acelity) and S&N. Both companies provided the NPWT
devices and associated consumable supplies in the assigned
regions of Germany as well as all necessary support and
information about the used material. The manufacturers
had no role in study design, data collection, data analysis,
data interpretation or writing of the report. All authors had
full access to all of the data (including statistical reports and
tables) in the study and take full responsibility for the accu-
racy of the data analysis.

results
Between 23 December 2011 and 12 August 2014, 386
patients were enrolled and randomly assigned to receive
NPWT (181) or SMWC (187) in the DiaFu study (figure 1)
in overall 40 study sites, which recruited minimum 1
patient and maximum 76 patients. Thirteen clinical inves-
tigators randomised more than 10 patients. Twenty- three
study sites enrolled only between one and four patients.
Most of these study sites refused further study participa-
tion due lack of time and staff for adequately performing
the documentation. In the further course of the trial
research nurses were hired by the independent scientific
institute overseeing the trial in order to support the docu-
mentation in the study sites whenever needed.

Demographics and relevant baseline characteristics
of the DFU are presented in table 1 and online supple-
mentary table 1. Baseline characteristics of the patients
in the NPWT and the SMWC arm are similar in the ITT
population without any relevant difference between the
treatment arms.

The baseline of the identified factors possibly influ-
encing wound closure is shown in table 2.

6 Seidel D, et al. BMJ Open 2020;10:e026345. doi:10.1136/bmjopen-2018-026345

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Figure 1 Trial profile (CONSORT); CONSORT, Consolidated Standards of Reporting Trials; NPWT, Negative Pressure Wound
Therapy; SMWC, Standard Moist Wound Care.

Details on revascularisation performed before study
start are shown in table 3.

results for the primary outcome wound closure in the Itt
population
In the ITT population, there was no significant differ-
ence between the treatment arms for either wound
closure rate (table 4) or time to complete wound closure
(p=0.244, log- rank test; figure 2) within 16 weeks. Begin-
ning in week 5, the number of study participants with
open wounds in the NPWT arm was lower than in the
SMWC arm (figure 2). However, after 16 weeks, the
difference between the treatment arms was only 2.5%
(95% CI −4.7% – 9.7%) (table 4). Wounds treated with

NPWT were approximately at the same risk of remaining
open as wounds treated with SMWC (RR 0.97 (95% CI
0.89−1.06)).

Since the cumulative number of patients with open
wounds was more than 70% after 16 weeks, we could not
calculate medians for the time to wound closure.

results for the secondary outcomes in the Itt population
Only one recurrence of the foot wound after complete,
sustained and confirmed closure was documented for
one study participant in the NPWT arm (table 4). Study
participants treated with NPWT were at slightly higher
risk for a recurrence than participants treated with SMWC
0.96 (95% CI 0.87−1.04).

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Table 1 Demographics and baseline characteristics of the ITT population

Demographics of the study population and baseline
parameters of the DFU
in the ITT population

Total
n=345 (100%)

NPWT
n=171 (49.6%)

SMWC
n=174 (50.4%)

Male
Female

267 of 345 (77.4%)
78 of 345 (22.6%)

133 of 171 (77.8%)
38 of 171 (22.2%)

134 of 174 (77.0%)
40 of 174 (23.0%)

Age (years) (n=345), mean (SD) 67.8 (11.9) 67.6 (12.3) 68.1 (11.5)

Height (n=340) (in cm), mean (SD) 174.1 (12.4) 173.4 (14.6) 174.8 (9.9)

Weight (n=335) (in kg), mean (SD) 93.3 (22) 92.7 (21.5) 93.8 (22.6)

Localisation of the ulcer

Regio calcanea
Dorsum pedis
Planta pedis
Metatarsalia
Phalanges distales
Phalanges mediales
Phalanges proximales
Hallux
Digitus pedis II
Digitus pedis III
Digitus pedis IV
Digitus minimus

39 (11.3%)
20 (5.8%)
56 (16.2%)
147 (42.6%)
64 (18.6%)
28 (8.1%)
40 (11.6%)
42 (12.2%)
22 (6.4%)
14 (4.1%)
20 (5.8%)
25 (7.2%)

17 (9.9%)
13 (7.6%)
30 (17.5%)
73 (42.7%)
31 (18.1%)
14 (8.2%)
21 (12.3%)
24 (14%)
10 (5.8%)
7 (4.1%)
7 (4.1%)
12 (7.0%)

22 (12.6%)
7 (4.0%)

26 (14.9%)
74 (42.5%)
33 (19%)
14 (8.0%)
19 (10.9%)
18 (10.3%)
12 (6.9%)
7 (4.0%)
13 (7.5%)
13 (7.5%)

Type of ulcer

Primary ulcer
Recurrence

279 of 342 (80.9%)
63 of 342 (18.3%)

136 of 170 (79.5%)
34 of 170 (19.9%)

143 of 172 (82.2%)
29 of 172 (16.7%)

Duration of ulcer (days)

n
Mean (SD)
Median (IQR)
Min – Max

335
189.7 (360.2)

83 (136)
0–4468

168
217.1 (458.1)

81 (140)
0–4468

167
162.1 (220)

85 (132)
0–1826

Wound surface area at randomisation (mm2)

Mean (SD)
Median (IQR)
Min- Max

1101 (2543)
491 (1079)
12–40 773

1060 (1536)
550 (1217)
20–13 188

1141 (3247)
471 (1007)
12–40 773

Wound surface area at randomisation for small wounds (mm2)

n
Mean (SD)
Median (IQR)
Min- Max

173
213 (136)
188 (220)
12–484

83
212 (138)
176 (220)
20–484

90
213 (135)
196 (222)
12–471

Wound surface area at randomisation for large wounds (mm2)

n
Mean (SD)
Median (IQR)
Min- Max

172
1995 (3377)
1276 (1482)
491–40773

88
1860 (1805)
1364 (1242)
520–13188

84
2135 (4474)
1242 (1708)
491–40773

Data are number (n) and percentage (%), mean and standard deviation (SD), median and interquartile range (IQR), and minimum – maximum (min –
max). ‘n=’ is stating the number of patients with actual available information. Based on the median wound surface area of all included patients, the
wounds were divided into an a priori planned subgroup of large (median wound surface area ≤484 mm² and a subgroup of small wounds (median
wound surface area >484 mm²).
DFU, diabetic foot ulcer; ITT, intention to treat; NPWT, negative pressure wound therapy; SMWC, standard moist wound care.

After 6 months, the number of study participants with
closed wounds was higher in the SMWC arm than in the
NPWT arm (36 of 174 (20.7 %) vs 24 of 171 (14.0 %)),
but the difference was not significant (p=1.00).

The time until optimal preparation of the wound for
further treatment to achieve a complete epithelialisation
(min 95% granulation tissue) was significantly shorter for
patients treated with NPWT (p=0.008) (table 5).

In the ITT population, wound surface area and wound
volume were similar at baseline (table 1) and decreased

continuously during the study treatment time of 16 weeks
in both treatment arms (online supplementary tables 2
and 3). The values are largely scattered. Measurements
derived from the blinded photo analysis using the W.H.A.T.
were smaller than the values documented by the clinical
investigators.

Wound tissue composition (online supplementary table
4) was similar in both treatment arms at baseline. Granu-
lation tissue values increased during the study treatment
period of 16 weeks and fibrin values decreased, with

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Table 2 Baseline of the identified factors possibly influencing wound closure in the ITT population

Confounders at baseline
in the ITT population

Total
n=345

NPWT
n=171

SMWC
n=174

Presence of neuropathy (sensation loss according to the PEDIS
classification system)

250 of 334 (72.5%) 125 of 166 (73.1%) 125 of 168 (71.8%)

Presence of a diabetic neuropathic osteoarthropathy 61 (17.7%) 30 (17.5%) 31 (17.8%)

Wagner grading of the ulcer
1: superficial ulcer of skin or subcutaneous tissue
2: ulcers extend into tendon, bone, or capsule
3: deep ulcer with osteomyelitis, or abscess
4: gangrene of toes or forefoot
5: midfoot or hindfoot gangrene

6 (1.7%)

225 (65.2%)
85 (24.6%)
26 (7.5%)
3 (0.9%)

2 (1.2%)

110 (64.3%)
45 (26.3%)
13 (7.6%)
1 (0.6%)

4 (2.3%)

115 (66.1%)
40 (23%)
13 (7.5%)
2 (1.1%)

Peripheral arterial occlusive disease (PAOD)
PAOD with critical limb ischaemia*

244 of 345 (70.7%)
26 of 243 (10.7%)

121 of 171 (70.8%)
15 of 121 (12.4%)

123 of 174 (70.7%)
11 of 122 (9.0%)

No chronic venous insufficiency (CVI)
CVI Widmer I
CVI Widmer II
CVI Widmer III

259 of 302 (75.1%)
25 of 302 (7.2%)
12 of 302 (3.5%)
6 of 302 (1.7%)

132 of 150 (77.2%)
11 of 150 (6.4%)
3 of 150 (1.8%)
4 of 150 (2.3%)

127 of 152 (73.0%)
14 of 152 (8.0%)
9 of 152 (5.2%)
2 of 152 (1.1%)

Presence of extreme foot deformities and malpositions of toes,
foot or the entire limb

59 of 342 (17.1%) 26 of 170 (15.2%) 33 of 172 (19.0%)

Untreated or therapy- refractory inflammation in the wound area 15 of 343 (4.3%) 7 of 170 (4.1%) 8 of 173 (4.6%)

Presence of a heel necrosis 23 of 342 (6.7%) 10 of 168 (5.8%) 13 of 174 (7.5%)

No lymphoedema
Primary lymphoedema
Secondary lymphoedema

282 of 340 (81.7%)
12 of 340 (3.5%)
46 of 340 (13.3%)

139 of 167 (81.3%)
5 of 167 (2.9%)

23 of 167 (13.5%)

143 of 173 (82.2%)
7 of 173 (4.0%)

23 of 173 (13.2%)

Clinical signs of inflammation (suspected infection) 159 of 344 (46.1%) 83 of 170 (48.5%) 76 of 174 (43.7%)

Local wound swab as part of the clinical routine 248 of 343 (71.9%) 126 of 170 (73.7%) 122 of 173 (70.1%)

Detection of germs within the local wound swab 205 of 247 (59.4%) 104 of 125 (60.8%) 101 of 122 (58.0%)

Haemoglobin
n
Mean (SD)

177 of 345

9.5 (3.2)

86 of 171
9.6 (3.1)

91 of 174
9.4 (3.3)

Haemoglobin A1c
n
Mean (SD)

32 of 345
15.6 (18.3)

13 of 171
16.8 (16.7)

19 of 174
14.7 (19.6)

Requiring dialysis 29 of 343 (8.4%) 15 of 170 (8.8%) 14 of 173 (8.0%)

Application of skin or dermal substitutes and with living cells that
produce growth factors

0 of 341 (0%) 0 of 169 (0%) 0 of 172 (0%)

Findings, diagnoses and procedures documented by the investigators are presented. Data are number (N), percentage (%), mean and standard
deviation (SD), and minimum – maximum (min – max). *Critical limb ischemia was defined as persistant pain at rest with regular analgesia for a period
of two weeks while nerve function is maintained or the occurence of ulceration or gangrene of the foot or toes with a systolic blood pressure of the
ankle below 50 mmHg or a systolic toe pressure below 30 mmHg or tcPO

2
<20 mmHg.

ITT, intention to treat; NPWT, negative pressure wound therapy; SMWC, standard moist wound care; tcPO
2
, transcutaneous oxygen measurement.

clinically documented values showing only minor differ-
ences between treatment arms. The values for necrotic
tissue were very low and did not differ relevantly between
the treatment arms. The results of the W.H.A.T. evalua-
tion for granulation and fibrin deviate markedly from the
values documented by the clinical investigators.

Patients treated with NPWT were approximately at
the same risk of undergoing an amputation or resec-
tion like patients treated with SMWC (RR 0.99 (95% CI
0.65−1.50)) (table 6).

Overall, pain levels were very low and decreased further
during the study treatment time (online supplementary
table 5). The values hardly differ between the treatment
arms at any observation time point.

At baseline, QoL (EQ5D) was significantly limited in
both treatment arms (online supplementary table 6).

EQ5D levels were improved in both study participants
reaching end of therapy as well as EOMT. On follow- up
after 6 months, all patients still showed increased EQ5D
levels in both treatment arms.

safety results
The number of study participants with AEs was signifi-
cantly higher in the NPWT arm (96 (56.1%)) than in the
SMWC arm (72 (41.4%)) (p=0.007) but only 16 (10.2%)
of the AEs in the NPWT arm were decided by the inves-
tigators to have a definite relation to the medical device
(table 7). The number of study participants with at least
one AE documented to be serious (SAE) was not signifi-
cantly different between the treatment arms (NPWT
n=63 (36.8%); SMWC n=58 (33.3%); p=0.50) (table 7).
None of the SAEs in the NWPT arm was documented as

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Table 3 Revascularisations performed in the ITT population before study start

Revascularisation before study start in the ITT population
Total

n=345
NPWT
n=171

SMWC
n=174

Performed revascularisation before study start
Percutaneous transluminal angioplasty (PTA)
PTA+stent
Veins- bypass
Polytetrafluoroethylene bypass
Thromboendarterectomy and patch plastic

23 of 345 (6.7%)
13 of 23 (57.0%)
1 of 23 (4.0%)

5 of 23 (22.0%)
1 of 23 (4.0%)
2 of 23 (9.0%)

9 of 171 (5.3%)
6 of 9 (67.0%)

0 of 9 (0%)
2 of 9 (22.0%)

0 of 9 (0%)
0 of 9 (0%)

14 of 174 (8.0%)
7 of 9 (50.0%)
1 of 9 (7.0%)

3 of 9 (21.0%)
1 of 9 (7.0%)

2 of 9 (14.0%)

Revascularisation with influence on the wound 22 of 23 (96.0%) 9 of 9 (100%) 13 of 14 (93.9.0%)

Sufficient revascularisation result*
Insufficient revascularisation result
Revascularisation result not assessable

20 of 23 (88.0%)
2 of 23 (9.0%)
1 of 23 (4.0%)

7 of 9 (78.0%)
1 of 9 (11.0%)
1 of 9 (11.0%)

13 of 14 (93.0%)
1 of 14 (7.0%)
0 of 14 (0%)

Data are n and percentage (%).
*Sufficient revascularisation result was defined as successful recanalisation of the tibial artery in which the foot lesion was located or, if it
was technically impossible to recanalise the respective artery, achievement of an unhindered inflow into at least one of the tibial vessels. The
evaluation of the revascularisation result was in the discretion of the attending physician.
ITT, intention to treat; NPWT, negative pressure wound therapy; SMWC, standard moist wound care.

Table 4 Study participants with wound closure (wound closure rate) and the number of participants with recurrences
(recurrence rate) in the ITT population

Wound closure and
recurrence rate in the ITT
population

Total
n=345

NPWT
n=171

SMWC
n=174

Difference
n
%

(95%CI)
p*

Patients with complete, sustained and confirmed wound closure within 16 weeks

n
%
(95% CI)

46 of 345
13.3

(9.8–17.8)

25 of 171
14.6

(9.5–21.6)

21 of 174
12.1

(7.5–18.4)

4
2.5

(−4.7 – 9.7)
0.53

Patients with recurrence of the diabetic foot wound after complete, sustained and confirmed closure within 6 months

n
%
(95% CI)

1 of 46
2.2

(0.1–12.1)

1 of 25
4

(0.1–22.3)

0 of 21
0

(0.0–14.3)

1
4

(−3.7 – 11.7)
1.00

Data show the number (N) of participants available for the analysis in total and for both treatment arms. Wound closures within the maximum
study treatment time of 16 weeks and recurrences during the follow- up of 6 months are shown with the number (N), the percentage (%) of
patients and the 95% Confidence Interval (CI).
*F=Fishers’ exact test.
ITT, intention to treat; NPWT, negative pressure wound therapy; SMWC, standard moist wound care.

definitely or possibly related to the medical device by the
investigators. Nine of 171 (5.3%) study participants in the
NPWT arm and 6 of 174 (3.5%) study participants in the
SMWC arm died during the study.

secondary analyses and subgroups
Of the factors possibly influencing the outcomes iden-
tified during study planning, the covariate POAD was
found to have significant influence on the endpoint
time until wound closure (p=0.026, log rank test). The
covariate clinical signs of inflammation (suspected
infection) had a significant influence on the wound
closure rate (p=0.012, χ2 test) in the univariate anal-
ysis of the primary endpoints. However, both covariates

were almost equally represented in both treatment
arms. Thus, the comparison of the treatment arms was
not influenced by these confounders. Furthermore, the
covariate suspected infection was found to be signifi-
cantly associated with both wound closure rate (logistic
regression; p=0.027) and time until wound closure (Cox
regression; p=0.037) in the multivariate confounder
analysis. Wound closure was significantly less likely in
wounds with suspected infection (OR 0.38).

In the subgroup of large wounds (wound surface area
at randomisation shown in table 1), wound closure rate
within 16 weeks was significantly higher in the NPWT
arm (13 of 88 (14.8 (7.4 to 22.2)%)) than in the SMWC

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Figure 2 Time until complete, sustained and verified wound
closure in the ITT population. NPWT, negative pressure
wound therapy; SMWC, standard moist wound care.

Table 5 Time until optimal preparation of the wound for further treatment (min 95% granulation tissue) in the ITT population

Time until optimal preparation of the wound bed
(min 95% granulation tissue) within 16 weeks
in the ITT population
N

available values

Total
n=183

NPWT
n=100

SMWC
n=83

Mean difference
(95% CI)

p*

Mean (SD) 42.7 (39.0) 35.6 (34.6) 51.4 (42.6) 15.8
(4.6−27.0)

0.008
Median (IQR) 31 (64) 22.0 (48.0) 49.0 (53.6)

Min–Max 0–127 0–127 0–115

Data show the number (N) of participants available for the analysis in total and for both treatment arms. Time until optimal preparation of the
wound is described with mean and standard deviation (SD); median and interquartile range (IQR); and minimum (min) and maximum (max).
*Student’s t- test.
ITT, intention to treat; NPWT, negative pressure wound therapy; SMWC, standard moist wound care.

arm (5 of 84 (6.0 (0.9 – 11.0)%)) (difference: n=8 (8.8
(−0.2 to 17.8)%), p=0.08). Study participants with large
wounds had a lower risk of not achieving wound closure
within 16 weeks when treated with NPWT (RR 0.91
(95% CI 0.82−1.0)) and achieved wound closure signifi-
cantly faster in the NPWT arm than in the SMWC arm
(p=0.027) (figure 3). The only recurrence occurred in
the subgroup of large wounds. Both major amputations
were performed in study participants with large wounds
treated with NPWT.

In the subgroup of small wounds (wound surface area
at randomisation shown in table 1), the time to reach
95% granulation tissue was significantly shorter for the
patients treated with NPWT than for those treated with
SMWC (p=0.005), but wound closure rate and time until
wound closure within 16 weeks were not significantly
different between the treatment arms (figure 4). Further

details of the subgroup analyses are presented in the
online supplementary tables 7 and 8.

results for the primary and secondary outcomes in the PP
population
Demographics, relevant baseline characteristics and the
results of the revascularisation before study start of the
PP population are presented in online supplementary
table 9. In the PP population, 14 of 44 study participants
(31.8% (95% CI 18.1%−45.6%)) treated with NPWT and
19 of 110 participants (17.3% (95% CI 10.2%−24.3%))
treated with SMWC achieved complete, sustained and
verified wound closure within 16 weeks, but the difference
was not significant (5 (14.5% (95% CI −1.0% − 30.0%);
p=0.053). Wounds treated with NPWT had a lower risk
of remaining open after 16 weeks (RR 0.82 (95% CI
0.66−1.03)) than wounds treated with SMWC. Time to
wound closure in the NPWT arm was significantly shorter
than in the SMWC arm (p=0.004) (figure 5). After 6
months, wound closure rate in the SMWC arm (30 of 110
(27.3% (95% CI 18.9%−35.6%))) was higher than in the
NPWT arm (11 of 44 (25.0% (95% CI 12.2−37.8))), but
the difference was not significant (n=19 (2.3% (95% CI
−13.0 − 17.6)); p=0.84). As in the ITT population, optimal
wound bed preparation was achieved significantly faster
in study participantss receiving NPWT (p<0.001). No
recurrences occurred after complete, sustained and
confirmed wound closure in the PP population. Neither
the number of participants with amputations or resections
nor the number of amputations or resections performed
differed significantly between the treatment arms. No
major amputations were performed in the PP population.
Further details on the results for the PP population are
presented in the online supplementary tables 10–16.

treatment compliance
Twenty- nine (17.0%) participants in the NPWT arm had
a temporary therapy change to SMWC (mean duration
20.5±21.6 days). In the SMWC arm, 17 (9.8%) partici-
pants had a temporary therapy change to NPWT (mean
duration 28.9±21.6 days). For only 2 of the 29 NPWT
participants (6.9%) with a temporary therapy change to
SMWC, the wound closure was achieved within 16 weeks,

11Seidel D, et al. BMJ Open 2020;10:e026345. doi:10.1136/bmjopen-2018-026345

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Table 6 Study participants with amputations/resections and the number of amputations/resections performed in the ITT
population

Amputations and resections
in the ITT population

Total
n=345

NPWT
n=171

SMWC
n=174

Difference
(95% CI)

p

Study participants with amputation or resection

n (%)
(95% CI)

71 (20.6%)
(16.3−24.8)

35 (20.5%)
(14.4 to 26.5)

36 (20.7%)
(14.7−26.7)

1 (0.2%)
(−19.0 − 18.6)

1.00 (F)

Total number of amputations and resections 102 45 57 12
0.89 (U)

Number of amputations and resections per study participant, n (%)

One event
Two events
Three events
Four events
Five events

49 (14.2%)
16 (4.6%)
4 (1.2%)
1 (0.3%)
1 (0.3%)

25 (14.6%
10 (5.8%)

0 (0%
0 (0%)
0 (0%)

24 (13.8%)
6 (3.4%)
4 (2.3%)
1 (0.6%)
1 (0.6%)

1 (0.8%)
4 (2.4%)
4 (2.3%)
1 (0.6%)
1 (0.6%)

Study participants with minor amputation 69 (20.0%) 33 (19.3%) 36 (20.7%) 3 (1.4%)
0.79 (F)

Study participants with major amputation 2 (0.6%) 2 (1.2%) 0 (0%) 2 (1.2%)
0.25 (F)

Data show the number (N) of participants, the percentage with the 95% CI, or the number of events accompanied with the respective
percentage values in total and for both treatment arms.
F, Fishers’ exact test; ITT, intention to treat; NPWT, negative pressure wound therapy ; SMWC, standard moist wound care; U, Mann-
Whitney U test.

whereas 16.2% (23 von 142) of the wounds of the NPWT
participants without therapy change were completely
closed.

A total of 57.3% (98 of 171) of the participants
randomised to NPWT completed treatment before
achieving a granulation surface of the wound of at least
95%. Fewer participants with this premature end of
NPWT (4.7%, n=8) achieved a complete wound closure
than participantss with no premature end of therapy (9.9,
n=17). Mean NPWT duration until premature end of
therapy was 28.5 days (SD 24.1), while a mean granulation
area of 59.6% (SD 30. 5) was achieved. For 131 partici-
pants (76. 6 %) in the NPWT arm less than the required
three dressing changes per week were documented. Nine-
teen participants (14. 5 %) with this protocol violation
achieved a complete wound closure. Six (15.4%) of the
39 NPWT participants who received at least three therapy
changes per week achieved a complete wound closure.

Documentation quality
In the NPWT arm, 52 study participants and in the SMWC
arm 43 participants were excluded from the PP popula-
tion due to missing documentation until the EOMT or
at wound closure confirmation (figure 1). In the eCRF,
wound closure was documented for 96 patients (NPWT 56
of 171; SMWC 40 of 174), but only 46 participants (NPWT
25; SMWC 21) met all criteria for a complete, verified
and sustained wound closure. For the wound closure visit,
seven wound photographs (NPWT 7; SMWC 0) and for
the wound closure confirmation visit four photographs
(NPWT 3; SMWC 1) were missing. In addition, two of the

existing wound photographs for wound closure (NPWT 0;
SMWC 2) and two photographs for wound closure confir-
mation (NPWT 1; SMWC 3) were not assessable by the
blinded observers due to serious quality issues. Further-
more, 23 (NPWT 15; SMWC 8) existing and assessable
wound photographs were not able to confirm wound
closure and 3 (NPWT 1; SMWC 2) photographs were not
able to confirm wound closure after 14 days.

DIsCussIOn
The DiaFu study did not demonstrate significant superi-
ority in wound closure rate or time to complete wound
closure for neither NPWT nor SMWC. Wound closure
rates were higher in the NPWT arm but did not signifi-
cantly differ from those in the SMWC arm. Time to
wound healing in the NPWT arm was lower than in the
SMWC arm, while the difference between the treatment
arms becomes statistically significant only in the PP popu-
lation. Thus, with this study, we were not able to confirm
our hypothesis that wound closure can be achieved more
often and faster with NPWT than with SMWC when used
in German real- life clinical practice. Previous RCTs, which
were the basis for sample size calculation, showed a higher
rate and a significant superiority in healing when using
NPWT on amputation and chronic wounds,16 17 but the
populations of these studies were different. Other than
the Armstrong study, the DiaFu study did not exclude
patients with venous insufficiency and included more
than twice as many patients. The studies of Armstrong

12 Seidel D, et al. BMJ Open 2020;10:e026345. doi:10.1136/bmjopen-2018-026345

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Table 7 Study participants with adverse events (AEs) and serious adverse events (SAEs) and the number of AEs and SAEs in
the ITT population

AEs and SAEs
in the ITT population

Total
n=345

NPWT
n=171

SMWC
n=174

Difference
(95% CI)

p

Study participants with at least one AE

n (%)
(95% CI)

168 (48.7%)
(43.4−54.0)

96 (56.1%)
(48.7−63.6)

72 (41.4%)
(34.1−48.7)

24 (14.7%)
(4.3−25.1)

p=0.007 (F)

Study participants with one AE (n)
Study participants with two or more AEs (n)

103
65

54
42

49
23

5
19

Total number of AEs (n) 269 167 102 65

AEs with relationship to the medical device

n
available

Yes, n (%)
Possible, n (%)
No, n (%)
Not assessable, n (%)

257
16 (6.2%)
13 (5.1%)

211 (82.1%)
17 (6.6%)

157
16 (10. 2%)
11 (7.0%)

117 (74.5%)
13 (8.3%)

100
0 (0%)

2 (2.0%)*
94 (94.0%)

4 (4.0%)

57
16 (10.2%)

9 (5%)
23 (19.5%)

9 (4.3%)

AEs with relationship to SMWC

n
available

Yes, n (%)
Possible, n (%)
No, n (%)
Not assessable, n (%)

185
2 (1.1%)
5 (2.7%)

163 (88.1%)
15 (8.1%)

110
0 (0%)

5 (4.5%)
96 (87.3%)

9 (8.2%)

75
2 (2.7%)
0 (0%)

67 (89.3%)
6 (8.0%)

35
2 (2.7%)
5 (4.5%)
29 (2.0%)
3 (0.2%)

AEs with relationship to the treatment procedure

n
available

Yes, n (%)
Possible, n (%)
No, n (%)
Not assessable, n (%)

244
10 (4.1%)
17 (7.0%)

191 (78.3%)
26 (10.7%)

148
6 (4.1%)

15 (10.1%)
111 (75.0%)
16 (10.8%)

96
4 (4.2%)
2 (2.1%)

80 (83.3%)
10 (10.4%)

52
2 (0.1%)
13 (8%)

31 (8.3%)
6 (0.4%)

Study participants with at least one SAE

n (%)
(95% CI)

121 (35.1%)
(30.0−40.1)

63 (36.8%)
(29.6−44.1)

58 (33.3%)
(26.3−40.3)

5 (3.5%)
(−6.6 − 13.6)
p=0.50 (F)

Study participants with one SAE (n)
Study participants with two or more SAEs (n)

90
31

45
18

45
13

0
5

Total number of SAEs (n) 163 87 76 11

SAEs with relationship to the medical device

n
available

Yes, n (%)
Possible, n (%)
No, n (%)
Not assessable, n (%)

161
0 (0%)
0 (0%)

154 (95.7%)
7 (4.3%)

85
0 (0%)
0 (0%)

79 (92.9%)
6 (7.1%)

76
0 (0%)
0 (0%)

75 (98.7%)
1 (1.3%)

9
0 (0%)
0 (0%)

4 (5.8%)
5 (5.8%)

SAEs with relationship to SMWC

n
available

Yes, n (%)
Possible
No, n (%)
Not assessable, n (%)

121
1 (0.8%)
1 (0.8%)

113 (93.4%)
6 (5.0%)

64
0 (0%)

1 (1.6%)
57 (89.1%)

6 (9.4%)

57
1 (1.8%)
0 (0%)

56 (98.2%)
0 (0%)

7
1 (1.8%)
1 (1.6%)
1 (9.1%)
6 (9.4%)

SAEs with relationship to the treatment procedure

n
available

Yes, n (%)
Possible
No, n (%)
Not assessable, n (%)

156
4 (2.6%)
2 (1.3%)

140 (89.7%)
10 (6.4%)

84
0 (0%)

2 (2.4%)
74 (88.1%)

8 (9.5%)

72
4 (5.6%)
0 (0%)

66 (91.7%)
2 (2.8%)

12
4 (5.6%)
2 (2.4%)
8 (10.6%)
6 (6.7%)

Data show the number (n) and the percentage (%) in total and for both treatment arms.
*No treatment change to NPWT has been documented. F=Fisher’s exact test (alpha=0.05).
ITT, intention to treat ; NPWT, negative pressure wound therapy; SMWC, standard moist wound care.

13Seidel D, et al. BMJ Open 2020;10:e026345. doi:10.1136/bmjopen-2018-026345

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Figure 3 Time until complete, sustained and verified wound
closure for the subgroup of large wounds. NPWT, negative
pressure wound therapy; SMWC, standard moist wound
care.

Figure 4 Time until complete, sustained and verified wound
closure for the subgroup of small wounds. NPWT, negative
pressure wound therapy; SMWC, standard moist wound
care.

Figure 5 Time until complete, sustained and verified wound
closure in the PP population; NPWT, negative pressure
wound therapy; SMWC, standard moist wound care.

and Blume excluded patients with Wagner stage 4; active
Charcot; uncontrolled hyperglycemia and therapy with
glucocorticoids, immunosuppressants or chemotherapy;
and required proof of adequate perfusion. The DiaFu

study did not exclude patients with impaired perfusion
but required adequate therapy of the circulatory disorder
according to clinical practice guidelines. In the DiaFu
study, we were able to show that the presence of PAOD at
randomisation had a significant influence on the time to
wound closure but not on the overall wound closure rate
within the maximum study treatment time. The number
of patients with critical limb ischaemia at baseline was low
and differed only slightly between the treatment arms.
As in clinical practice, in the DiaFu study, adequate treat-
ment of concomitant diseases was mandatory. Invasive
therapy of PAOD could be performed before initiation
of wound therapy as well as during the study treatment
period, if the wound needed pretreatment as a basis for
the revascularisation procedure or if new or recurrent
critical ischaemia occured.

The presence of clinical signs of inflammation
(suspected infection) at randomisation had a significant
effect on both, time to wound closure and wound closure
rate within 16 weeks. Both covariates were equally repre-
sented in the treatment arms, thus the differences in time
until wound closure and wound closure rate were not
affected by these confounders.

However, the probably most serious factors negatively
influencing treatment and outcome are documentation
deficiencies and deviations from treatment guidelines.
Temporary therapy changes and premature therapy cessa-
tion negatively impacted the patient relevant treatment
outcome wound closure in study participants treated with
NPWT. Missing study visits resulting in low numbers of
complete endpoint documentations strongly affected the

14 Seidel D, et al. BMJ Open 2020;10:e026345. doi:10.1136/bmjopen-2018-026345

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proof of the outcome wound closure in both, the NPWT
arm and the SMWC arm.

Optimal preparation of the wound bed (95% granula-
tion tissue) was achieved significantly earlier when using
NPWT in the ITT and the PP population, but the overall
rate of wound closures was low. Wound bed preparation
and granulation tissue formation are important prereq-
uisites for wound healing but are not a proof of treat-
ment effectiveness and cannot serve as a basis for benefit
assessment.

Although significantly more AEs were documented in
the NPWT arm, only a small number of these events were
related to the medical device according to the investi-
gator’ s assessment. Mortality rates were very low in both
treatment arms, and there was no significant difference
between the treatment arms regarding amputations and
resections performed during the study. Only two major
amputations have been performed in patients with large
wounds treated with NPWT. None of the treatments
resulted in an additional impairment of the patients’
QoL during study treatment time or follow- up. Time until
complete wound closure was significantly shorter with
NPWT than with SMWC in the subgroup of large wounds,
which indicates that NPWT has the potential to be a valu-
able treatment option for this kind of wounds.

In the DiaFu study, methods against bias were imple-
mented whenever possible in order to avoid bias that
have been described by several systematic reviews,18–21 but
blinding of study participants as well as attending physi-
cians and nurses was not possible due to the nature of
NPWT.

Not addressing and analysing all factors influencing
the overall treatment outcome like targeted pressure
relief, continuous infection control and adequate treat-
ment of the underlying disease during the study treat-
ment and observation period may be seen as a limitation
of this healthcare research study. Study sites have been
selected based on a self- disclosure by means of a qualifica-
tion checklist and cross checks using quality reports. This
ensured that all prerequisites were met for guideline-
compliant patient care. Nevertheless, even in the applica-
tion of NPWT, there were deviations from the standards.

In order to support the decision- making process of the
German G- BA on general reimbursement of NPWT in
German outpatient care, the real- life clinical practice DiaFu
study included patients with chronic DFUs of neuropathic
and angiopathic origin regardless of whether a simple
wound cleansing, tissue debridement or even amputa-
tion was necessary prior to application of wound therapy
targeted to achieve complete wound closure. The study was
performed without excluding concomitant diseases nega-
tively impacting wound healing; with therapy application in
the discretion of the attending physician; and with evalua-
tion of patient relevant outcome. Thus, results can easy be
generalised and applied in clinical practice settings. Anyway,
shortcomings in data quality negatively impacted the study
results, and statements about specific patient groups were
not possible. A high number of study participants needed

to be excluded from the PP population (NPWT arm: 127
of 171 (74%), SMWC arm 64 of 174 (37%)). For most of
these participants, documentation was lacking until the end
of the maximum treatment period (total=88, NPWT=49,
SMWC=39) (figure 1). In the primary analysis based on
the ITT population, it was assumed that these patients did
not achieve wound closure within 16 weeks’ study treat-
ment and observation time (using the LOCF method, the
open wound status was ‘carried forward’ until the end of
the maximum treatment period. This may have led to a
false negative bias in the outcome wound closure in the
ITT population. Due to the high loss of patients and the
difference in the number of participants excluded from the
treatment arms, the validity of the PP analysis is very limited.

COnClusIOns
NPWT was not superior to SMWC when evaluated in
German real- life clinical practice. Missing compliance
with therapy guidelines and poor documentation quality
led to restrictions in achieving the patient- relevant
endpoint complete wound closure and prevents a clear
proof of effectiveness. The question if NPWT is supe-
rior to SMWC for treating diabetic foot wounds remains
unanswered due to the limitations of the DiaFu study.
Although the study protocol required adequate moni-
toring and therapy of the concomitant diseases, the
presence of POAD and infection at randomisation had
a significant influence on the outcome wound closure.
Despite all limitations, NPWT showed a significant supe-
riority in optimal wound bed preparation. This indicates
that NPWT works according to its intended use and has a
potential to be an effective treatment option. The results
of the PP population suggest that without the negative
impact of premature treatment cessation, temporary
changes of the randomised therapy and partly incomplete
documentation NPWT may be more effective for treating
diabetic foot wounds than SMWC. In Germany, NPWT
should be evaluated again after implementation of a suffi-
cient, well- considered and widely accepted concept for
quality control. In a future healthcare research study, the
treatment outcome before and after the implementation
of these quality measures should be evaluated, for which
the results of this trial may serve as a basis.

Author affiliations
1Institut für Forschung in der Operativen Medizin (IFOM), Universität Witten/
Herdecke, Köln, Germany
2Klinik für Gefäß- und Thoraxchirurgie, Städtisches Klinikum Karlsruhe gGmbH,
Karlsruhe, Germany
3Praxis für Herzkreislauferkrankungen, Ettlingen, Germany
4Innere Medizin, Max- Grundig Klinik, Bühlerhöhe, Germany
5Gefäßchirurgische Klinik, Knappschaftskrankenhaus Bottrop GmbH, Bottrop,
Germany
6Innere Medizin, St. Remigius Krankenhaus Opladen, Leverkusen, Germany
7Gemeinschaftspraxis Schlotmann- Hochlenert- Zavaleta- Haberstock, Köln, Germany
8Chirurgische Praxis Wetzel- Roth, Buchloe, Germany
9Klinik für Innere Medizin/Diabetologie, Marien Hospital Dortmund- Hombruch,
Dortmund, Germany
10Allgemein- und Viszeralchirurgie, Helfenstein Klinik, Geisslingen, Germany

15Seidel D, et al. BMJ Open 2020;10:e026345. doi:10.1136/bmjopen-2018-026345

Open access

11Chirurgische Praxis Rothenaicher, München, Germany
12Klinik für Gefäßchirurgie, Thüringen- Kliniken “Georgius Agricola” GmbH, Saalfeld,
Germany
13Diabetes Klinik, Diabetes Zentrum Mergentheim, Bad Mergentheim, Germany
14Department fur Humanmedizin, Universität Witten/Herdecke, Witten, Germany
15Medizinische Hochschule Brandenburg -Theodor Fontane, Neuruppin, Germany

Acknowledgements The authors thank all investigators, nurses, patients and
partners for supporting the study. At least one patient was included in the following
facilities: HSK – Dr. Horst Schmidt Kliniken GmbH Klinik für Gefäßchirurgie Ludwig-
Erhard- Straße 100 65199 Wiesbaden; Asklepios Westklinikum Hamburg Zentrum
für Gefäßmedizin Suurheid 20 22559 Hamburg; Knappschaftskrankenhaus Bottrop
Gefäßchirurgische Klinik Osterfelderstraße 157 46242 Bottrop; Städtisches
Klinikum Karlsruhe Klinik für Gefäß- und Thoraxchirurgie Moltkestraße 90 76133
Karlsruhe; Gemeinschaftspraxis Schlotmann- Hochlenert- Zavaleta- Haberstock
Merheimer Straße 217 50733 Köln; Klinikum Döbeln Abt. für Gefäßchirurgie
Sörmitzer Straße 10 04720 Döbeln; Klinikum Bielefeld Mitte Klinik für Allgemeine
Innere Medizin Teutoburger Straße 50 33604 Bielefeld; Klinikum Frankfurt/
Oder Klinik für Gefäßchirurgie Müllroser Chaussee 7 15236 Frankfurt/Oder;
Weißeritztal- Kliniken GmbH Medizinische Klinik III Bürgerstraße 7 01705 Freital;
Krankenhaus Porz am Rhein Klinik für Gefäßchirurgie Urbacher Weg 19 51149
Köln; St. Remigius Krankenhaus Opladen Innere Medizin An St. Remigius 26
51379 Leverkusen; Marien Hospital Dortmund- Hombruch Klinik für Innere
Medizin/Diabetologie Gablonzstraße 9 44225 Dortmund; Zentrum für Chirurgie
Klinik für Gefäß- und Endovascularchirurgie Theodor- Stern- Kai 7, Haus 23C/EG
60590 Frankfurt am Main; Facharzt für Chirurgie Thorax- Kardiovaskularchirurgie
Hindenburgstraße 1 86807 Buchloe; Helfenstein Klinik Geisslingen Allgemein- und
Viszeralchirurgie Eybstraße 16 73312 Geislingen/Steige; Paracelsus- Klinik am
Silbersee Wundzentrum Hannover Oertzeweg 24 30851 Langenhagen; Klinikum
Darmstadt Chirurgische Klinik III Grafenstraße 9 64283 Darmstadt; Ortenau
Klinikum Offenburg- Ebertplatz Klinik für Allgemein-, Viszeral- und Gefäßchirurgie
Ebertplatz 12 77654 Offenburg; Thüringen- Kliniken “Georgius Agricola” GmbH
Klinik für Gefäßchirurgie Rainweg 68 07318 Saalfeld; Klinikum Dorothea Christiane
Erxleben GmbH Klinik für Allgemein-, Viszeral- und Gefäßchirurgie Ditfurter Weg
24 06484 Quedlinburg; Franziskus- Krankenhaus Berlin Abt. für Innere Medizin
Budapester Straße 15-19 10787 Berlin; Hegau- Bodensee Klinikum Radolfzell (HBK)
Klinik für Innere Medizin Hausherrenstraße 12 78315 Radolfzell; Diabetologische
Schwerpunktpraxis Dr. med. Hansjörg Mühlen & Partner Ruhrorter Straße 195
47119 Duisburg; Kliniken Maria Hilf Mönchengladbach Klinik für Gefäßchirurgie
und Angiologie Sandradstraße 43 41061 Mönchengladbach; Städtisches Klinikum
München/Bogenhausen Klinik für Endokrinologie, Diabetologie und Angiologie
Englschalkingerstraße 77 81925 München; Gerhard Rothenaicher Facharzt für
Chirurgie Cosimastraße 2 81927 München; Bürgerhospital Frankfurt am Main
Interdisziplinäres Zentrum Diabetischer Fuß (DDG) Nibelungenallee 37- 41 60318
Frankfurt am Main; Gemeinschaftspraxis für Chirurgie und Gefäßmedizin Drs. Alter/
Pourhassan/Heim Klosterstraße 12 46145 Oberhausen; Ev. KH Königin Elisabeth
Herzberge gGmbH Abt. für Kardiologie, Angiologie und Diabetologie Herzbergstraße
79 10365 Berlin; Städtisches Klinikum Neunkirchen gGmbH Abt. für Gefäßchirurgie
& Phlebologie Brunnenstraße 20 66538 Neunkirchen; Westküstenklinikum Heide
Klinik für Viszeral- und Gefäßchirurgie Esmarchstraße 50 25746 Heide/Holstein;
Chir. Praxisgemeinschaft am Bayenthalgürtel Praxis Dr. med. Gerald Engels
Bayenthalgürtel 45 50968 Köln; Malteser Krankenhaus – St. Franziskus- Hospital
Medizinische Klinik I, Abt. für Diabetologie Waldstraße 17 24939 Flensburg; St.
Marienkrankenhaus Siegen gGmbH Klinik für Gastroenterologie Kampenstraße
51 57072 Siegen; Krankenhaus Bietigheim Klinik für Innere Medizin, Kardiologie,
Endokrinologie, Diabetologie und Internistische Intensivmedizin Riedstraße 12
74321 Bietigheim- Bissingen; Asklepios Kliniken Harburg Eißendorfer Pferdeweg
52 21075 Hamburg; Diabetologikum Ludwigshafen Diabetes- Schwerpunktpraxis
Ludwigsplatz 9 67059 Ludwigshafen; Mariannen- Hospital Werl Abt. für Chirurgie
Unnaer Straße 15 59457 Werl; Diabetes Klinik GmbH & Co KG Theodor- Klotzbücher-
Straße 12 97980 Bad Mergentheim; Institut für Diabetesforschung Münster GmbH
Hohenzollernring 70 48145 Münster. The study was initiated by a consortium
of 19 statutory German health insurance funds represented by the AOK federal
association (AOK- Bundesverband – AOK- BV), the association of alternative health
insurance funds (Verband der Ersatzkrankenkassen – vdek) and the minors
(Knappschaft). In order to guarantee outpatient care for all study participants
without any restrictions, the contracting health insurance companies provided
integrated care contracts for outpatient negative pressure wound therapy. A
project advisory board was implemented to coordinate all processes and project
partners. The board comprised two representatives each from the statutory health
insurance funds, the management company and the sponsor as well as one

representative each from the participating medical device manufacturers (KCI
and smith & nephew). Representing the contracting authority (statutory German
health insurance funds) Dr. Gerhard Schillinger (AOK- BV) and Ute Leonhard (vdek)
acted as contact persons for all aspects of the project. The management company
“Gesundheitsforen Leipzig” has been entirely responsible for the logistics of the
study. Central tasks of the management company included the recruitment of
study sites and patients, the development of the IT infrastructure including the
documentation, communication and invoicing software as well as the processing
of all payments. The manufacturers Kinetic Concepts Incorporated (KCI) (Acelity)
and smith & nephew provided the NPWT devices as well as support and training for
the investigators and financed the study.The Private University of Witten/Herdecke
gGmbH acted as the Sponsor of the trial and the Institute for Research in Operative
Medicine with its former director Prof. E.A.M. Neugebauer, the current interim
head Prof. Rolf Lefering and the head of the division for clinical research Dörthe
Seidel was responsible for the scientific conception, the evaluation as well as the
reporting and publication of the study. Prof. Dr. Rolf Lefering was responsible for the
statistical planning and analysis. PD Dr. Peter Krüger was responsible for the data
management of the study. Special thanks are going to Stefan Bauer, who supported
the data management as well as the statistical analysis and reporting. We would
like to thank Sophie Thorn, who checked the article as a native English speaker
with regard to spelling and grammar.

Contributors DS was the principal coordinating investigator. She conceived the
study, reviewed the scientific literature and was responsible for study design,
data analysis, data interpretation, writing and reviewing of the report. She is the
lead author and takes overall responsibility for this report. She affirms that the
manuscript is an honest, accurate and transparent account of the study being
reported; that no important aspects of the study have been omitted; and that any
discrepancies from the study as originally planned (and, if relevant, registered)
have been explained. MS and HL were study investigators and contributed to
study design, data collection and interpretation and reviewed the report. GW, PM,
WW- R and DH were study investigators and contributed to data collection and
data interpretation and reviewed the report. KS, MH, GR, TK and KZ were study
investigators and contributed to data collection and reviewed the report. EN
contributed to study design and data interpretation and reviewed the report. All
authors approved the final version of the report.

Funding Through a European tender, the study was initiated by a consortium
of 19 statutory German health insurance funds, which provided integrated care
contracts for all study participants and for up to 7000 patients with acute and
chronic wounds in Germany; defined basic rules for study design based on the
requirements of the German authorities; and provided a critical review of the study
protocol and the final report. The study was funded by the manufacturers KCI and
S&N. Both companies provided the NPWT devices and associated consumable
supplies in the assigned regions of Germany as well as all necessary support and
information about the used material. All authors had full access to all of the data
(including statistical reports and tables) in the study and take full responsibility for
the accuracy of the data analysis.

Disclaimer The manufacturers had no role in study design, data collection, data
analysis, data interpretation or writing of the report.

Competing interests The German statutory health insurance companies
commissioned the Witten/Herdecke University (UW/H) to plan, conduct, analyse and
publish the study. DS is an employee of the UW/H. The study has been financed
by the manufacturers KCI (Acelity) and S&N. DS received a consulting fee for the
presentation of the study during an event organised by the manufacturer Hartmann.
During study planning and conduct, EN was an employee of the UW/H. He was
the director of the Institut für Forschung in der Operativen Medizin. The clinical
investigators MS, HL, GW, PM, DH, WW- R, KS, MH, GR, TK and KZ received a case
fee of 1000€ for each patient included in the DiaFu study in order to compensate
for the additional organisational and especially the documentation effort during
trial conduct. Furthermore, all investigators received compensation for travelling
to the investigator meetings. The institutions of the investigators used integrated
care contracts for NPWT during study conduct in order to provide best practice for
the study participants during outpatient care. GW and WW- R are members of the
scientific advisory board of the manufacturer KCI (now Acelity).

Patient consent for publication Not required.

ethics approval Ethical approval of the main ethical committee (EC): Ethical
Committee of the University of Witten- Herdecke, has been fully granted without any
conditions. Due to performing the trial according to § 23b MPG (German Medical
Device Act), participating study sites in Germany only received a consultation for
the main clinical investigator according to professional law by the respective EC. All

16 Seidel D, et al. BMJ Open 2020;10:e026345. doi:10.1136/bmjopen-2018-026345

Open access

investigators have been fully approved by the respective ECs. An evaluation of the
study’s content by ECs of participating study sites in Germany was not applicable.
All study participants gave written informed consent prior to randomisation and any
trial related procedure.

Provenance and peer review Not commissioned; externally peer reviewed.

Data availability statement Data are available on reasonable request. The
datasets analysed for the results presented in this article are available from the
corresponding author. Datasets are available in German language.

Open access This is an open access article distributed in accordance with the
Creative Commons Attribution Non Commercial (CC BY- NC 4.0) license, which
permits others to distribute, remix, adapt, build upon this work non- commercially,
and license their derivative works on different terms, provided the original work is
properly cited, appropriate credit is given, any changes made indicated, and the use
is non- commercial. See: http:// creativecommons. org/ licenses/ by- nc/ 4. 0/.

OrCID iD
Dörthe Seidel http:// orcid. org/ 0000- 0002- 2287- 5217

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