NPWT Evidence Library
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Diabetic foot wounds

Diabetic foot wounds (post-surgical and non-healing)

SA evidence position: Moderatei 170 sources7 supporting NPWT at GRADE High or Moderate certainty
The SA evidence position is this library's synthesis, not an official guideline.

Post-surgical and non-healing diabetic foot wounds — one of the best-evidenced NPWT indications, once ischaemia is excluded.

Protocol (PDF)All 170 sourcesReferences (RIS)Spreadsheet (CSV)

Evidence in one minute

What the evidence supports

  • After debridement or partial foot amputation, NPWT heals more wounds, and sooner, than moist dressings: 56% vs 39% (Armstrong 2005) and 43% vs 29% (Blume 2008).
  • Preparing the wound bed for a skin graft: grafting at 7 rather than 14 days (Wu 2023).
  • Guidelines suggest it for ulcers that have not improved after 4–8 weeks of good standard care, on low-certainty evidence (SVS/APMA/SVM 2016, Grade 2B; IWGDF 2023; Japanese Dermatological Association 2026, weak).

Uncertain or not shown

  • The largest trial of open surgical wounds, mostly in diabetic patients (SWHSI-2, 686 patients), found no faster healing, GRADE High, and NPWT was not cost-effective (Arundel 2025).
  • Fewer amputations: Cochrane RR 0.33, but low certainty from three trials; Monami 2025 found no effect on major amputation.
  • Chronic ulcers in routine care: the German DiaFu trial (345 patients) found no difference in closure at 16 weeks, with benefit only in wounds larger than about 5 cm².
  • Most trials are small, unblinded and often manufacturer-funded; NPWT prepares the wound bed more reliably than it closes the wound.

Harms and cautions

  • Adverse events were no more frequent than with standard care in the trials; no deaths attributable to NPWT in the pooled real-world data.

Do not use when

  • Ischaemia has not been assessed and addressed. Use a toe pressure or TcPO2; the ankle–brachial index is unreliable in diabetes.
  • Infection is uncontrolled, necrotic tissue remains, or off-loading is not in place.
Usual settings: −80 to −125 mmHg; a lower pressure for the ischaemic foot (see the protocol).

Key studies

Meta-analysis / SRGRADE ⊕⊕◯◯ Low2018Supports NPWT

The Cochrane review behind the amputation figure, and the certainty attached to it is low

Negative pressure wound therapy for treating foot wounds in people with diabetes mellitus (Cochrane Review) — Liu Z, Dumville JC, Hinchliffe RJ, Cullum N, Game F, Stubbs N, et al · Cochrane Database of Systematic Reviews 2018, Issue 10. Art. No.: CD010318
What it found

Lavery 2014, 40 participants, four weeks: NPWT at 75 mmHg against NPWT at 125 mmHg. No difference in wounds closed or covered with surgery (RR 0.83, 0.47 to 1.47) and none in adverse events (RR 1.50, 0.28 to 8.04), both very low certainty, and no data at all on healing, time to healing or amputation.

This wiki argues about pressure repeatedly, and this is the only randomised head-to-head it contains. It supports one sentence and no more: at these two settings, over four weeks, in forty people, no difference was demonstrated on the outcomes that were measured — and the primary outcomes were not measured. It is not evidence that 75 mmHg is as good as 125 mmHg. It is evidence that nobody has done the trial.

Limitations
  • The healing benefit is partly a surgical-closure benefit awarded by unblinded clinicians. In Armstrong 2005, 12/77 (22%) NPWT wounds against 8/85 (9%) dressing wounds were classed as healed after closure surgery, and the review states plainly that there was no protocol rule and no blinded committee governing when to operate. Every healing and time-to-healing estimate on this page inherits that.
  • All studies were at unclear risk of blinding bias. Only two of eleven were at low risk for allocation concealment (Armstrong 2005, Blume 2008); five did not describe sequence generation at all; Nain 2011 was at high risk for attrition.
  • The two largest trials were funded by KCI, the manufacturer of V.A.C., and they carry the healing, time-to-healing and most of the amputation signal. Nine of the eleven trials did not report their funding source at all.
  • Armstrong 2005's median healing times do not reconcile with its own Kaplan-Meier curve — the review records that the medians in the figure "seemed to be higher" than the 56 and 77 days reported. The familiar "21 days shorter" rests on that unreconciled pair.
  • Three arithmetic and presentation defects. The text gives postoperative amputation denominators as 142 versus 145 where Analysis 1.3 totals 150; the foot-ulcer time-to-healing summary says 342 participants where the abstract and the trial say 341; and a single-study forest plot prints I² 100% on zero degrees of freedom.
  • No publication-bias assessment anywhere, no comparison reaching ten trials — against a background the review itself cites of NPWT trials terminated or completed and never published.
  • The search closed in January 2018. Every diabetic-foot RCT in this library from 2019 onward postdates it, and several large syntheses held here now pool more than twice as many trials.
  • Off-loading, the single most important co-intervention in this disease, was inconsistently reported and could not be balance-checked across arms.
Appraisal and reference

CAT: OCEBM 1 · This is the certainty the review itself assigns, reproduced rather than re-derived, because its GRADE process is documented and its reasons are stated per outcome. FOOT ULCERS - proportion healed RR 1.40 (1.14 to 1.72), I squared 0%, 5 studies, 486 participants, LOW, downgraded ONCE for risk of bias (no blinded outcome assessment) and ONCE for imprecision (small samples, wide intervals). Time to healing HR 1.82 (1.27 to 2.60) from ONE study of 341, LOW, same two downgrades. AMPUTATION RR 0.33 (0.15 to 0.70), I squared 0%, 3 studies, 441 participants, LOW, downgraded ONCE for risk of bias and ONCE for imprecision - the denominator is 441 and the certainty is low, and both belong in any sentence that quotes the 0.33. Postoperative (post-amputation) wounds - proportion healed RR 1.44 (1.03 to 2.01) from ONE study of 162, LOW; time to healing HR 1.91 (1.21 to 2.99), median 21 days shorter, same single study, LOW; both downgraded once for risk of bias (some blinded outcome assessment, but the review could not judge the effect of non-blinded decisions about further surgery) and once for imprecision. Amputation in the postoperative comparison is a DIFFERENT and WEAKER result - RR 0.38 (0.14 to 1.02), 2 studies, 292 participants, VERY LOW, downgraded once for risk of bias and TWICE for imprecision because the interval spans appreciable benefit and appreciable harm. 75 mmHg VERSUS 125 mmHg - wounds closed or covered with surgery RR 0.83 (0.47 to 1.47) and adverse events RR 1.50 (0.28 to 8.04), ONE study of 40, VERY LOW, downgraded once for risk of bias and TWICE for very serious imprecision; there were NO DATA on healing, time to healing or amputation. Nothing was ever downgraded for inconsistency - every pooled estimate returned I squared 0%, and the largest single-comparison heterogeneity anywhere is I squared 28% for wounds closed or covered with surgery. Nothing was downgraded for publication bias either, and that is a gap rather than a clean bill: no comparison reached ten trials so no funnel plot was possible, and the review cites Peinemann 2008 on the large number of NPWT trials terminated or completed and never published. The structural limit on every estimate: healing counts include wounds closed by surgery at the discretion of clinicians who knew the allocation, with no protocol rule governing when to operate - 12/77 (22%) in the NPWT arm of Armstrong 2005 against 8/85 (9%) on dressings. The review says so twice and the wiki must say so too.

Figures: Figures checked

Liu Z, Dumville JC, Hinchliffe RJ, Cullum N, Game F, Stubbs N, Sweeting M, Peinemann F. Negative pressure wound therapy for treating foot wounds in people with diabetes mellitus. Cochrane Database of Systematic Reviews. 2018;(10):CD010318 (First update (pub3). Protocol Issue 1, 2013; review first published Issue 10, 2013. Funded by the NIHR through Cochrane Infrastructure and NIHR Cochrane Programme Grant 13/89/08.)
PubMedDOIReviewed 2026-08-09
RCTGRADE ⊕⊕⊕◯ Moderate2005Supports NPWT

NPWT after partial diabetic foot amputation

Negative pressure wound therapy after partial diabetic foot amputation: a multicentre, randomised controlled trial — Armstrong DG, Lavery LA · The Lancet
What it found

Primary outcome — complete healing at 112 days: 43/77 (56%) NPWT vs 33/85 (39%) control, p=0.040. Recomputed here, since the paper publishes no interval for it: RR 1.44 (95% CI 1.03–2.01), absolute difference +17.0% (95% CI +1.8 to +32.2), NNT 5.9 (95% CI 3.1 to 54.3). The interval is wide and its lower bound is close to no effect.

From the trial profile (read off Figure 1, not inferred): of the 43 healed on NPWT, 31 closed without surgical intervention and 12 with; of the 33 healed on control, 25 without and 8 with.

Secondary outcomes

  • Time to complete closure faster with NPWT, p=0.005.
  • Time to 76–100% granulation: median 42 days (IQR 40–56) vs 84 days (57–112), p=0.002; restricted to patients presenting with 0–25% granulation, 42 (14–56) vs 82 (28–112), p=0.010.
  • Second amputation: 2/77 (3%) NPWT vs 9/85 (11%) control. Recomputed: RR 0.25 (95% CI 0.05–1.10) — the ratio interval crosses no effect — while the absolute difference is −8.0% (95% CI −15.4 to −0.5), which does not. The discussion's claim that NPWT patients were "less than a fourth as likely" to need re-amputation is the point estimate only; the paper reports no interval and the interval crosses 1. Re-amputation was a secondary endpoint and the authors state the trial was not powered for it.
  • High-level (above-foot) amputation: 0/77 NPWT vs 5/85 control (3 below-knee, 2 above-knee), p=0.060.
  • Needed subsequent debridement: 16/77 (21%) vs 22/85 (26%), p=0.464.

Safety. At least one adverse event in 40/77 (52%) NPWT vs 46/85 (54%) control, p=0.875; the commonest class was infections. Mean duration of treatment-related adverse events in the control group 24.3 days (SD 34.5).

Attrition. 19 patients in each arm withdrew before the last active-phase visit without closure — 19/77 (24.7%) NPWT and 19/85 (22.4%) control, 38/162 (23.5%) overall; the difference in withdrawal proportion was not significant (two-tailed Fisher p=0.753). Because the denominators for the primary outcome remain 77 and 85, these withdrawals are counted as unhealed, which is the conservative handling.

Limitations
  • Manufacturer-funded and manufacturer-designed; both authors on the KCI speakers' bureau. Declare it.
  • No pressure or mode reported, so the protocol cannot be reproduced from this paper.
  • 23.5% withdrew before the last active-phase visit without closure, balanced between arms but substantial; the primary outcome depends on how those patients are counted, and counting them as unhealed is what the published denominators do.
  • Unblindable intervention with clinician-assessed closure. The paper reports planimetric wound tracing but no blinded outcome adjudication — though IQWiG establishes from correspondence that the planimetric evaluation was done in ignorance of allocation and agreed with the clinicians except in two control-group cases. The unblinded judgement that matters is the indication for surgical closure, which feeds the primary outcome.
  • The re-amputation and high-level-amputation findings are secondary, underpowered, their ratio intervals cross no effect, and their ITT convention was judged possibly anti-conservative by IQWiG (see the section above). They are a signal worth citing with the interval and that caveat attached, not a demonstrated effect.
  • Generalisability is bounded by the perfusion inclusion criterion. This trial says nothing about NPWT in a critically ischaemic foot, and extrapolating it there is the commonest overreach in NPWT motivations — see Ischaemic / borderline-perfusion wounds — low-pressure NPWT (and when NOT to use it).
  • Recent hyperbaric oxygen, growth factors and bioengineered tissue were exclusions, so the trial does not speak to NPWT combined with those adjuncts — relevant where a patient is also under hyperbaric care.
  • Against arundel 2025 swhsi2 rct (686 patients, HR 1.08 for time to healing, GRADE High, null) the two are not in direct conflict: Armstrong studied post-amputation wounds with mandated perfusion and optimised off-loading against moist dressings over 112 days, while SWHSI-2 studied surgical wounds healing by secondary intention against usual care over 12 months. Cite both and state the difference in population and comparator.
Appraisal and reference

CAT: OCEBM 2 · Re-judged from the full text 2026-07-30; the previous rationale read only 'Start High (rct); −1 risk of bias' and had no domain detail. Start HIGH (individually randomised trial with ITT analysis, registered, multicentre). −1 for risk of bias, on three grounds taken together rather than any one alone: the intervention is unblindable and closure was assessed by treating clinicians with no blinded adjudication; 23.5% of patients (19 per arm) withdrew before the last active-phase visit without closure, and although balanced (Fisher p=0.753) and conservatively counted as unhealed, that is a quarter of the sample; and the trial was funded, designed and monitored by KCI USA, the device manufacturer, with both authors on its speakers' bureau. NO further downgrade for imprecision on the PRIMARY outcome: the recomputed RR is 1.44 (95% CI 1.03–2.01), which excludes no effect, and the population and comparator are directly relevant. Net MODERATE. The secondary amputation outcomes are rated separately and lower — see below — because their intervals cross no effect. Confounding-by-severity does not apply here (randomised), and the balanced baseline table supports that.

Figures: Figures checked

Armstrong DG, Lavery LA; Diabetic Foot Study Consortium. Negative pressure wound therapy after partial diabetic foot amputation: a multicentre, randomised controlled trial. Lancet. 2005;366(9498):1704-10 (funded by KCI USA, the manufacturer of the VAC system, which designed and monitored the trial and reviewed the manuscript before release; both authors received KCI research funding and were members of the KCI speakers' bureau)
PubMedDOIReviewed 2026-09-18
RCTGRADE ⊕⊕⊕◯ Moderate2007Supports NPWT

NPWT vs advanced moist wound therapy for DFUs

Comparison of Negative Pressure Wound Therapy Using Vacuum-Assisted Closure With Advanced Moist Wound Therapy in the Treatment of Diabetic Foot Ulcers — Blume PA, Walters J, Payne W, Ayala J, Lantis J · Diabetes Care
What it found
  • Complete closure achieved in 73/169 (43.2%) with NPWT vs 48/166 (28.9%) with AMWT (p=0.007).
  • Kaplan-Meier median time to 100% closure was 96 days for NPWT vs not determinable for AMWT (p=0.001).
  • Significantly fewer secondary amputations with NPWT (p=0.035).
  • No significant difference in infection, cellulitis, or osteomyelitis at 6 months.
  • Conclusion: NPWT is as safe as, and more efficacious than, AMWT.
Limitations
  • Positive trial; the comparator was advanced moist wound therapy rather than basic care, so the effect is over and above modern standard treatment.
  • Off-loading was standardised, which may not reflect all real-world practice.
Appraisal and reference

CAT: OCEBM 2 · Start HIGH (randomised trial). -1 risk of bias: the intervention cannot be masked, so patients, treating clinicians and the assessors judging 'complete closure' all knew the allocation, and closure of a diabetic foot ulcer is a judgement rather than a measurement; no blinded adjudication is described. NO downgrade for indirectness: this is the target population (n=342, multicentre), the outcome is complete closure rather than a surrogate, and - importantly for how the trial is quoted - the comparator is ADVANCED moist wound therapy, not saline gauze, so the effect is over and above modern standard care rather than against a straw comparator. That is the strongest single feature of this trial and the reason its estimate survives the comparator critique that sinks several others in this pool. NO downgrade for imprecision: 43.2% (73/169) versus 28.9% (48/166), p=0.007, on adequate numbers. NO downgrade for inconsistency (single trial). Net moderate. What the rating is about: a moderate-certainty demonstration that NPWT closes more diabetic foot ulcers than advanced moist wound therapy within the trial period, in a population in whom off-loading was standardised. It does NOT establish an amputation benefit - secondary amputations were fewer at p=0.035, but that was a secondary endpoint on small numbers - and it found no difference in infection, cellulitis or osteomyelitis at six months, which is worth stating before someone else does.

Figures: Figures checked

Blume PA, Walters J, Payne W, Ayala J, Lantis J. Comparison of Negative Pressure Wound Therapy Using Vacuum-Assisted Closure With Advanced Moist Wound Therapy in the Treatment of Diabetic Foot Ulcers. Diabetes Care. 2008;31(4):631-6.
PubMedDOIReviewed 2026-09-18
RCTGRADE ⊕⊕⊕◯ Moderate2020Challenges NPWT

German DiaFu-RCT (NPWT vs standard moist wound care)

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 — Seidel D, Storck M, Lawall H, Wozniak G, Mauckner P, Hochlenert D, et al · BMJ Open
What it found
  • Wound closure within 16 weeks was NOT significantly different: difference 2.5% (95% CI −4.7% to 9.7%; p=0.53).
  • Time to wound closure was also not significantly different (p=0.244).
  • 191 patients had missing endpoints or protocol deviations.
  • Overall wound closure rate was low; documentation deficits and guideline deviations affected the outcome.
  • Conclusion: NPWT was not superior to standard moist wound care in German real-life practice.
Limitations
  • NEGATIVE / non-superiority trial: NPWT was not superior to standard moist wound care.
  • High rate of missing endpoints and protocol deviations (191 patients), plus documentation deficits and guideline deviations, and a low overall closure rate, which complicate interpretation.
  • Trial registration NCT01480362.
Appraisal and reference

CAT: OCEBM 2 · Start HIGH (randomised trial). -1 risk of bias: despite blinded outcome assessment - this trial's methodological strength, and rare in the field - 191 patients had missing endpoints or protocol deviations, and the investigators themselves report documentation deficits and guideline deviations. In a superiority trial reporting no difference, attrition and protocol deviation on that scale threaten the NULL as much as they would threaten a positive result, and the accurate reading is that they widen the uncertainty in both directions. NO downgrade for indirectness - this is the entire point of the trial: German ROUTINE diabetic-foot care across 40 centres, the setting to which the explanatory trials are meant to generalise. NO downgrade for imprecision: n=345 mITT, and the interval (-4.7% to +9.7%) excludes a large benefit, which is what a null result needs in order to be informative. NO downgrade for inconsistency (single trial). Net moderate. What the rating is about: a moderate-certainty demonstration that the effect seen in the explanatory trials is NOT reproduced under service conditions. It does not refute Armstrong or Blume; it establishes that efficacy and effectiveness diverge here, which is a different and more useful claim. The low overall closure rate in BOTH arms is itself the finding a South African service should attend to - it suggests the binding constraint in routine care is delivery of the whole package, not the choice of dressing.

Figures: Figures checked

Seidel D, Storck M, Lawall H, Wozniak G, Mauckner P, Hochlenert D, Wetzel-Roth W, Sondern K, Hahn M, Rothenaicher G, Krönert T, Zink K, Neugebauer E. 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(3):e026345.
PubMedDOIReviewed 2026-09-18
RCTGRADE ⊕⊕⊕⊕ High2025Challenges NPWT

SWHSI-2: NPWT versus usual care for open surgical wounds healing by secondary intention — the largest negative trial in this file, in this practice's own population

Negative pressure wound therapy versus usual care in patients with surgical wound healing by secondary intention in the UK (SWHSI-2): an open-label, multicentre, parallel-group, randomised controlled trial — Arundel C, Mandefield L, Fairhurst C, Baird K, Gkekas A, Saramago P, et al · Lancet 2025;405:1689-99
What it found
  • Primary outcome — no clear evidence of benefit: HR 1.08 (95% CI 0.88-1.32), p=0.47 (abstract p 1689; table 2 p 1694). Median time to healing 187 days (95% CI 169-226) with NPWT versus 195 days (158-213) with usual care — a difference of 8 days (p 1695).
  • The confidence interval's upper bound is the trial's own target effect. The sample size was set "to detect a 25% reduction in median time to healing (from 86 days with usual care to 65 days with NPWT equating to a hazard ratio [HR] of 1·32 and a control group event proportion of 0·95), with 90% power" and 20% attrition, requiring 696 participants, 348 per group (p 1693). The paper says so itself: the HR of 1.08 "narrowly includes our target effect size" (p 1695). This is the strongest statement the result will bear: the trial did not exclude its own pre-specified clinically meaningful effect — it failed to demonstrate it. The authors put the same point in plain terms: the finding "is, however uncertain and NPWT might increase the time to healing by as much as 12% or decrease it by as much as 32%" (p 1695).
  • Healing within 12 months occurred in 202 (57.9%) NPWT and 196 (58.2%) usual-care participants; 159 (23.2%) were censored for death, amputation, withdrawal or loss to follow-up (83 [23.8%] NPWT, 76 [22.6%] usual care) (p 1695).
  • Masked photographic assessment agreed with the unmasked primary outcome: HR 1.13 (95% CI 0.87-1.47), p=0.36 (table 2 p 1694). Results were also consistent across all sensitivity analyses (competing risks by Fine and Gray, correction for stratification errors, adjustment for the baseline smoking and alcohol imbalance, a Complier Average Causal Effect instrumental-variable analysis) and the pre-specified subgroup analysis by previous SWHSI history (p 1695).
  • No significant difference in any clinical secondary outcome (table 2 p 1694, denominators n=320 per arm): hospital admission 63 (19.7%) vs 58 (18.1%), OR 1.13 (0.76-1.69), p=0.54; reoperation 78 (24.4%) vs 69 (21.6%), OR 1.20 (0.82-1.74), p=0.35; amputation 35 (10.9%) vs 36 (11.2%), OR 0.98 (0.60-1.62), p=0.95; wound infection 102 (31.9%) vs 100 (31.2%), OR 1.05 (0.75-1.48), p=0.77; antibiotic use for the SWHSI 211 (65.9%) vs 210 (65.6%), OR 1.01 (0.70-1.45), p=0.96; death 40 (11.5%) vs 43 (12.8%), OR 0.89 (0.56-1.41), p=0.61.
  • No significant difference in any patient-reported outcome at any timepoint — Bluebelle Wound Healing Questionnaire at 3, 6 and 12 months (p=0.66, 0.70, 0.22) and visual-analogue wound pain at 3, 6 and 12 months (p=0.85, 0.94, 0.80) (table 2 p 1694).
  • Harms were similar. 448 adverse events, of which 14 were serious (nine participants in the NPWT group and five participants in the usual care group); 124 were deemed potentially related to treatment (abstract p 1689). At least one adverse event occurred in 150/349 (43.0%) NPWT and 139/337 (41.2%) usual care, risk difference -1.7% (95% CI -9.1 to 5.7); wound infection was the commonest event in both arms, and major wound infection the commonest serious event. Ten of the 14 serious events (71.4%) were judged unrelated or unlikely to be related to study treatment (table 3 p 1695; p 1696).
  • NPWT was not cost-effective. Adjusted incremental QALYs +0.007 (95% CI -0.024 to 0.038) and adjusted incremental cost +£251.44 (95% CI -£2192.63 to £2695.52) over 12 months, neither significant. Incremental net monetary benefit -£93.22 at £20 000 and -£18.65 at £30 000 per QALY; probability of cost-effectiveness 47.2% at £20 000 and 49.7% at £30 000 (p 1696). Unadjusted mean per-participant cost was £5782.13 (95% CI £4151.32-£7412.95) for NPWT and £5801.99 (£3897.19-£7706.78) for usual care. Sensitivity analyses reduced the probability of cost-effectiveness further when participants who died were excluded and when cross-over was accounted for; a complete-case analysis suggested NPWT might be cost-effective but rests on 75.7% missing data and the authors call it likely biased (p 1696).
  • The population is close to a South African vascular unit's. 549 of 686 (80.0%) were diabetic — 281 (85.4%) and 268 (84.5%) of those with the field recorded; peripheral vascular disease 181 (55.0%) and 168 (53.0%); wounds arose after vascular surgery in 619 (90.2%), with surgery type recorded as vascular in 314 (90.0%) and 305 (90.5%); wound location foot 279 (79.9%) and 272 (80.7%), leg 40 (11.5%) and 29 (8.6%), abdomen 11 (3.2%) and 13 (3.9%); 620 (90.4%) were on the foot or leg. Median wound area 18.30 cm² (IQR 8.10-35.00) and 18.00 cm² (7.26-33.75); the wound was classified dirty in 190 (54.4%) and 210 (62.3%) and the surgery was an emergency in 205 (58.7%) and 194 (57.6%). Median age 63 years (IQR 55-72), 74.8% male, 91.8% White (table 1 pp 1693-94; results p 1695).
  • Funding and interests are clean. NIHR HTA Programme, project reference 17/42/94, and "The funder of the study had no role in study design, data collection, data analysis, data interpretation, or writing of the report" (p 1695). Declared interests are minimal: CA reports support for attendance to present the study at Vascular Society of Great Britain and Ireland annual meetings, LM reports independent Data Monitoring and Ethics Committee membership for two unrelated studies (REACH-ASD and ACORN II), and "All other authors declare no competing interests" (p 1698). This matters — the trial cannot be dismissed as an interested party's work, in either direction.
  • For context the paper cites the contrary aggregate evidence and explains it: the Cochrane review on this question found only two small trials at risk of bias, and "A separate meta-analysis of 48 low-quality studies at high risk of bias suggested a benefit in healing for SWHSI treated with NPWT (OR 1·56 [95% CI 1·15-2·13]; p=0·008)" (p 1696).
Limitations
  • The assumed control-group healing rate was badly wrong, and this weakens the trial's own power. The sample size assumed a control-group event proportion of 0.95 and a usual-care median healing time of 86 days (p 1693). Observed: 58.2% of usual-care participants healed within 12 months and the observed median was 195 days (p 1695) — more than double the assumption, with 23.2% censored. Fewer healing events than planned means less information than 90% power implies, which is part of why the interval still contains HR 1.32.
  • The primary outcome was unmasked. This is mitigated, not removed, by the masked photographic secondary analysis — which pointed the same way (HR 1.13) but which the authors say overestimated healing time because it censored wounds the masked assessors deemed unhealed, and should be read with caution (p 1697).
  • Substantial crossover in both directions. 42 of 349 NPWT-allocated participants did not receive the intervention, and 45 of 337 usual-care participants received NPWT at some point during the study (figure 1 p 1692). Intention-to-treat with contamination of that size biases toward the null; the CACE analysis was pre-specified to address it and did not change the conclusion (p 1695).
  • The exclusions bound the applicability, and two of them matter most. Of 658 ineligible patients, 249 were excluded because they were already receiving or had previously received NPWT on the SWHSI, and 114 because the wound was contraindicated to NPWT; also excluded were 113 whose wound was not considered ready for NPWT, 47 where a vacuum seal could not be obtained, 44 with active systemic infection, 32 malnourished, 25 with unclear undermining, 25 with tissue or eschar present, 15 with delayed primary closure planned, 10 at risk of bleeding, 8 with exposed vessels or organs and 6 with chronic non-surgical wounds (figure 1 p 1692). The 249 are the important number: patients whose clinicians had already committed them to NPWT were systematically removed, so the trial population is by construction the population in whom clinicians were uncertain. It says nothing about the patient in whom NPWT is already running and working.
  • Two internal inconsistencies, both in the source. (i) The Results text reports "14 serious adverse events were reported (nine participants in the NPWT group and five participants in the usual care group)" (p 1696), but table 3 gives participants with at least one serious adverse event as 9 (2.6%) and 4 (1.2%) — the 9 and 5 are events, not participants, and the arm-level percentages in table 3 confirm 9 and 5 events. (ii) The marginal citation line printed on the first page reads "Lancet 2024; 405: 1689-99" while the running footer of every page reads "Vol 405 May 10, 2025" and the paper was published online 15 April 2025 — the year in that margin is a typesetting error; 2025 is correct.
  • Recruitment ran through the COVID-19 pandemic; study activity was paused by the funder, sponsor and trial management group between March and July 2020, with site capacity effects afterwards, and from March 2020 weekly follow-up calls were made centrally rather than by site research nurses (pp 1691, 1697).
  • Patient-reported outcome response rates were lower than anticipated; the WHQ and pain collection timepoints were revised in October 2022 to reduce participant burden, which helped only slightly (pp 1691, 1697). WHQ denominators fell from 195/190 at 3 months to 86/74 at 12 months (table 2 p 1694).
  • The economic analysis is UK-specific and the authors say so — "the economic analysis conducted is specific to the UK and so the cost-effectiveness findings might not be generalisable to other countries" (p 1697). It cannot be transplanted to a South African scheme without local costing, in either direction.
  • Non-lower-limb recruitment failed, so this is effectively a lower-limb trial despite an all-body protocol (p 1697).
  • Gender and race were recorded by the investigator from medical records or discussion with the patient as necessary (p 1691), and the cohort was 91.8% White — a further limit on transfer to a South African population.
Appraisal and reference

CAT: OCEBM 2 · Start High (rct); no downgrade. RoB 2 overall Some concerns, from one domain only (unmasked primary outcome) — and that domain is mitigated by a pre-specified masked photographic assessment that pointed the same way (HR 1.13, 95% CI 0.87-1.47), while unmasking in an open-label trial biases towards the intervention and therefore cannot manufacture a null. Imprecision was considered and NOT taken: the 95% CI 0.88-1.32 narrowly includes the trial's own pre-specified target HR of 1.32, which is a real borderline, but with 686 randomised, 398 healing events, and concordance across every sensitivity, subgroup, competing-risks, CACE and masked analysis, the benefit-of-the-doubt tie-breaker (Dr Weir, 19 Jul 2026) holds this at High rather than Moderate. A null result from a well-conducted, publicly funded trial is not a weak result.

Figures: Figures checked

Arundel C, Mandefield L, Fairhurst C, Baird K, Gkekas A, Saramago P, Chetter I, on behalf of the SWHSI-2 Trial Investigators. Negative pressure wound therapy versus usual care in patients with surgical wound healing by secondary intention in the UK (SWHSI-2): an open-label, multicentre, parallel-group, randomised controlled trial. Lancet. 2025;405:1689-99 (Funded by the NIHR Health Technology Assessment Programme (17/42/94); the funder had no role in design, data collection, analysis, interpretation or writing)
PubMedDOIReviewed 2026-07-30
Guideline / consensusGuideline quality 5/72016Supports NPWT

SVS / APMA / SVM clinical practice guideline on the diabetic foot

The management of diabetic foot: a clinical practice guideline by the Society for Vascular Surgery in collaboration with the American Podiatric Medical Association and the Society for Vascular Medicine — Hingorani A, LaMuraglia GM, Henke P, Meissner MH, Loretz L, Zinszer KM, et al · Journal of Vascular Surgery 2016;63(2 Suppl):3S-21S
What it found
  • §4 Wound care, Recommendation 6 (Grade 2B) — the NPWT recommendation, verbatim (the guideline restarts its numbering in each of its five sections, so an unqualified "Recommendation 6" is ambiguous — §1 Recommendation 6 is a different statement, recommending against prophylactic arterial revascularisation. Always cite the section. Verified against the source 2026-07-29): "We suggest the use of negative pressure wound therapy (NPWT) for chronic diabetic foot wounds that do not demonstrate expected healing progression with standard or advanced wound dressings after 4 to 8 weeks of therapy."
  • The supporting evidence cited is the multicentre RCT of 342 patients (Blume — Blume 2007), in which NPWT was as safe as and more efficacious than advanced moist wound therapy: faster healing to closure, significantly fewer secondary amputations, and significantly fewer home-care therapy days.
  • Further cited evidence: reduced time to complete healing and reduced duration and frequency of hospital admission; decreased healing time and improved quality of life; increased rate of granulation tissue appearance; reduced length of hospitalisation with reduced amputation rates and functional residual extremity; and reduced time to granulation with clearing of bacterial infection.
  • Retrospective reimbursement-claims analysis showed reduced amputation numbers in NPWT groups against traditional therapies regardless of wound depth, and decreased resource utilisation through fewer nursing visits.
  • The guideline explicitly qualifies its own recommendation on cost: "Consideration of high cost of NPWT products and access to trained personnel for application of NPWT dressings should be weighed in choosing this treatment modality."
  • §4 Wound care, Recommendation 5 (Grade 1B) — the stronger and, for this unit, the more important one: re-evaluation of vascular status, infection control and off-loading is recommended to ensure optimisation before adjunctive wound therapy is started. Note the asymmetry: the prerequisite is a Grade 1 recommendation while NPWT itself is only Grade 2.
  • Adjunctive therapies are graded comparatively. NPWT and PDGF (becaplermin) both sit at Grade 2B; the guideline states evidence was "most supportive for hyperbaric oxygen therapy". Corrected 2026-07-29: this page previously called HBOT a pharmacological adjunct. The commissioned review covered three adjunctive categories — hyperbaric oxygen, arterial pump devices and pharmacologic agents — and HBOT is not in the pharmacologic group.
Limitations
  • Published 2016 with searches closing earlier; it predates the entire 2020–2025 DFU trial and meta-analytic literature now held here.
  • Grade 2B is a weak recommendation on moderate-quality evidence — do not present it as a mandate.
  • US practice context: reimbursement-claims evidence and care pathways do not transfer to South African funding, and the guideline says nothing about PMB or SA coding.
  • It addresses the diabetic foot only. It is not authority for the infected vascular graft, the groin wound or the open abdomen.
  • Society guidelines of this period did not routinely publish full conflict-of-interest detail per recommendation; the adjunctive-therapy section covers commercially marketed products.
Appraisal and reference

AGREE II: Recommended — Scope 78% · Stakeholders 61% · Rigour 71% · Clarity 100% · Applicability 54% · Independence 25%

Figures: Figures checked

Hingorani A, LaMuraglia GM, Henke P, Meissner MH, Loretz L, Zinszer KM, Driver VR, Frykberg R, Carman TL, Marston W, Mills JL, Murad MH. The management of diabetic foot: a clinical practice guideline by the Society for Vascular Surgery in collaboration with the American Podiatric Medical Association and the Society for Vascular Medicine. J Vasc Surg. 2016;63(2 Suppl):3S–21S.
PubMedDOIReviewed 2026-07-26

Guidance

South African guidance
WHASA 2021 (AGREE II 4/7) — first-line, ischaemia excluded; WHASA 2015 diabetic-foot consensus (AGREE II 4/7)
International guidance
SVS/APMA/SVM 2016 (AGREE II 5/7; Grade 2B); JDA 2026 Japanese dermatology guideline (AGREE II 4/7; weak, certainty C); Ji 2021 consensus (AGREE II 5/7); Vig 2011 international consensus (industry-supported; AGREE II: use with modifications)

Scores are this library's AGREE II appraisal of each guideline (out of 7). About guideline quality.

Coding and funding (South Africa)
A research aid. Verify codes against the current ICD-10 MIT, scheme rules and the PMB regulations before submission.
ICD-10
E11.5, E10.5, E14.5, L97
PMB
915E (diabetic PVD / gangrene); diabetes-with-complications pathway

All wound types: coding and funding

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