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, Chetter I, SWHSI-2 Trial Investigators
- DOI
- 10.1016/S0140-6736(25)00143-6
- Record issued
- 2026-08-10
- Engine
- 7.29.0
- Exported
- 2026-09-22
Prepared by Alpha1. This document is confidential: it is intended for the recipient it was shared with and must not be redistributed. The live record at alpha1science.com/verify/e0f6d222-db6b-4e43-95cc-da8c51c71781 is authoritative.
How this rating was calculated
- IntegrityIntegrity concern ×5−2.5★
- ReportingEthical approvals partially met−0.25★
- ReportingKey resources partially met−0.25★
- ReportingData & code availability partially met−0.25★
- The numeric-impossibility checks (GRIM/GRIMMER/DEBIT/SPRITE) did not run: 8 reported means were read, and their group size is not stated where the values are printed (this source has no machine-readable table structure). These checks need the count the mean was averaged over, so none was performed.
- 01Internal contradictions in the reported numbers
Comorbidity percentages in Table 1 use inconsistent denominators; e.g., for NPWT cardiovascular disease, 218/329=66.3%, 111/349=31.8%, and 20/349=5.7% cannot all be true percentages of the same group.
Yes | 218 (66·3%) | 228 (71·9%) | No | 111 (31·8%) | 89 (26·4%) | Missing | 20 (5·7%) | 20 (5·9%)
Table 1reviewer’s wording - 02Internal contradictions in the reported numbers
The abstract reports five usual-care participants with serious adverse events, but Table 3 reports four (1.2%).
“14 were serious (nine participants in the NPWT group and five participants in the usual care group)”
Table 3Find in source
This Kaimen Rigor review uses Kaimen Rigor reviewers trained on a curated corpus of high-fidelity and retracted papers, with expert supervision and curation. It can still make mistakes; verify each finding against the source before relying on it.
The SWHSI-2 trial is a well-designed and largely well-reported pragmatic RCT with a strong scientific premise, rigorous randomisation, pre-specified power calculation, and transparent reporting of a null primary result; the independent statistics verification found all 18 checked reported tests consistent. The main weaknesses are reporting gaps rather than validity threats: no explicit statement of a named regulatory framework, non-specific identification of the NPWT device and usual-care dressings, data only promised (not yet deposited) with no shared code, and no CONSORT checklist citation. Several internal inconsistencies (serious-adverse-event counts, Table 1 denominator mismatches, censoring accounting) warrant correction.
Three independent reviewer runs of the same model were synthesised; reviewers split on ethical approvals (warn vs pass) and data code availability (pass vs warn), resolved by the strict scoring rule and majority evidence. Specialised verification: 18/18 statistics consistent, 0 retracted/not-found references, 2/2 reproducibility links live, preregistration confirmed (ISRCTN26277546). Caveat: the statistics check covers only a subset of reported tests (those with test statistic+df or effect+CI); the remainder is unverified, not confirmed.
Numerical inconsistencies
1 finding · worst mediumValues that contradict each other or are impossible for the stated sample: recomputed p-values and test statistics, GRIM/GRIMMER checks on summary numbers, percentages against their own counts, totals against their parts, and estimates against their own confidence intervals.
- Internal contradictions in the reported numbersAssessed
Recomputed 18 tests: 18 consistent, 0 inconsistent; 2 recomputed directly from the reported test statistics, 16 via agent-written checks.
- CONSISTENTreported p = .470 · recomputed p = .457Recomputed hazard ratio 1.08 (95% CI 0.88–1.32), reported p=0.47
“hazard ratio 1.08 [95% CI 0.88–1.32], p=0.47”
Taken as given: 0.88–1.32 is a two-sided 95% confidence interval for the hazard ratio of 1.08, not a range, an IQR, or a different interval level; the hazard ratio is a RATIO measure, so the interval is symmetric on the log scale; p=0.47 is the p for THIS estimate, not for another comparison in the same sentenceMethod: back the two-tailed p out of the log-scale CI width and compare it against the printed pHow we recomputed it: pCI(1.08, 0.88, 1.32, 1) - CONSISTENTreported p = .008 · recomputed p = .005Recomputed OR 1.56 (95% CI 1.15–2.13), reported p=0.008
“OR 1.56 [95% CI 1.15–2.13]; p=0.008”
Taken as given: 1.15–2.13 is a two-sided 95% confidence interval for the OR of 1.56, not a range, an IQR, or a different interval level; the OR is a RATIO measure, so the interval is symmetric on the log scale; p=0.008 is the p for THIS estimate, not for another comparison in the same sentenceMethod: back the two-tailed p out of the log-scale CI width and compare it against the printed pHow we recomputed it: pCI(1.56, 1.15, 2.13, 1) - CONSISTENTreported p = .360 · recomputed p = .361Reviewer 1Masked outcome assessment hazard ratio p-value.
“HR 1·13 (0·87 to 1·47) | 0·36”
Taken as given: Table 2 reports HR 1.13 with 95% CI 0.87–1.47 and p=0.36 for the masked assessment.; The CI is two-sided at 95%.; pCI computes the Wald-type two-tailed p from the log-HR and CI-derived SE.Method: Normal-approximation Wald p from log(HR) and CI-derived SE (two-tailed).How we recomputed it: pCI(1.13, 0.87, 1.47, 1) - CONSISTENTreported p = .540 · recomputed p = .549Reviewers 1, 2, 3Hospital admission odds ratio p-value.
“Hospital admission | n=320; 63 (19·7%) | n=320; 58 (18·1%) | OR 1·13 (0·76 to 1·69) | 0·54”
Taken as given: Table 2 reports OR 1.13 with 95% CI 0.76–1.69 and p=0.54.; The CI is two-sided at 95%.; pCI computes the Wald-type two-tailed p from the log-OR and CI-derived SE.Method: Normal-approximation Wald p from log(OR) and CI-derived SE (two-tailed).How we recomputed it: pCI(1.13, 0.76, 1.69, 1) - CONSISTENTreported p = .950 · recomputed p = .936Reviewers 1, 2Amputation odds ratio p-value.
“Amputation | n=320; 35 (10·9%) | n=320; 36 (11·2%) | OR 0·98 (0·60 to 1·62) | 0·95”
Taken as given: Table 2 reports OR 0.98 with 95% CI 0.60–1.62 and p=0.95.; The CI is two-sided at 95%.; pCI computes the Wald-type two-tailed p from the log-OR and CI-derived SE.Method: Normal-approximation Wald p from log(OR) and CI-derived SE (two-tailed).How we recomputed it: pCI(0.98, 0.60, 1.62, 1) - CONSISTENTreported p = .610 · recomputed p = .621Reviewers 1, 2, 3Death odds ratio p-value.
“Death | n=349; 40 (11·5%) | n=337; 43 (12·8%) | OR 0·89 (0·56 to 1·41) | 0·61”
Taken as given: Table 2 reports OR 0.89 with 95% CI 0.56–1.41 and p=0.61.; The CI is two-sided at 95%.; pCI computes the Wald-type two-tailed p from the log-OR and CI-derived SE.Method: Normal-approximation Wald p from log(OR) and CI-derived SE (two-tailed).How we recomputed it: pCI(0.89, 0.56, 1.41, 1) - CONSISTENTreported p = .660 · recomputed p = .661Reviewer 1WHQ at 3 months mean-adjusted-difference p-value.
“WHQ at 3 months | n=195; mean 7·01 (5·08) | n=190; mean 7·15 (5·72) | Mean adjusted difference 0·29 (−1·01 to 1·58) | 0·66”
Taken as given: Table 2 reports a mean adjusted difference of 0.29 with 95% CI −1.01 to 1.58 and p=0.66.; The CI is two-sided at 95%.; pCI computes the Wald-type two-tailed p from the difference and CI-derived SE.Method: Normal-approximation Wald p from the mean difference and CI-derived SE (two-tailed).How we recomputed it: pCI(0.29, -1.01, 1.58, 0) - CONSISTENTreported p = .470 · recomputed p = .457Reviewer 2Primary HR for time to healing (NPWT vs usual care)
“HR 1·08 (0·88 to 1·32) | 0·47”
Taken as given: The 95% CI is on the hazard-ratio scale and is two-sided; The p-value is two-sided from a Cox model using a normal approximation for log(HR)Method: Two-sided p derived from the reported HR and 95% CI using pCI with log=1.How we recomputed it: pCI(1.08,0.88,1.32,1) - CONSISTENTreported p = .360 · recomputed p = .361Reviewer 2Masked-assessment HR for time to healing
“HR 1·13 (0·87 to 1·47) | 0·36”
Taken as given: The 95% CI is on the hazard-ratio scale and is two-sided; The p-value is two-sided from the same Cox-model approachMethod: Two-sided p from reported HR and 95% CI using pCI with log=1.How we recomputed it: pCI(1.13,0.87,1.47,1) - CONSISTENTreported p = .350 · recomputed p = .342Reviewer 2OR for reoperation
“OR 1·20 (0·82 to 1·74) | 0·35”
Taken as given: The 95% CI is on the odds-ratio scale and is two-sided; The p-value is two-sided from logistic regression using a normal approximation for log(OR)Method: Two-sided p from reported OR and 95% CI using pCI with log=1.How we recomputed it: pCI(1.20,0.82,1.74,1) - CONSISTENTreported p = .770 · recomputed p = .778Reviewer 2OR for wound infection
“OR 1·05 (0·75 to 1·48) | 0·77”
Taken as given: The 95% CI is on the odds-ratio scale and is two-sided; The p-value is two-sided from logistic regression using a normal approximation for log(OR)Method: Two-sided p from reported OR and 95% CI using pCI with log=1.How we recomputed it: pCI(1.05,0.75,1.48,1) - CONSISTENTreported p = .960 · recomputed p = .957Reviewer 2OR for antibiotic use
“OR 1·01 (0·70 to 1·45) | 0·96”
Taken as given: The 95% CI is on the odds-ratio scale and is two-sided; The p-value is two-sided from logistic regression using a normal approximation for log(OR)Method: Two-sided p from reported OR and 95% CI using pCI with log=1.How we recomputed it: pCI(1.01,0.70,1.45,1) - CONSISTENTreported p = .660 · recomputed p = .661Reviewer 2Adjusted mean difference in WHQ at 3 months
“Mean adjusted difference 0·29 (−1·01 to 1·58) | 0·66”
Taken as given: The 95% CI is for a mean difference and is two-sided; The p-value is two-sided from a mixed model using a normal approximationMethod: Two-sided p from reported mean difference and 95% CI using pCI with log=0.How we recomputed it: pCI(0.29,-1.01,1.58,0) - CONSISTENTreported p = .700 · recomputed p = .701Reviewer 2Adjusted mean difference in WHQ at 6 months
“Mean adjusted difference 0·29 (−1·19 to 1·77) | 0·70”
Taken as given: The 95% CI is for a mean difference and is two-sided; The p-value is two-sided from a mixed model using a normal approximationMethod: Two-sided p from reported mean difference and 95% CI using pCI with log=0.How we recomputed it: pCI(0.29,-1.19,1.77,0) - CONSISTENTreported p = .220 · recomputed p = .220Reviewer 2Adjusted mean difference in WHQ at 12 months
“Mean adjusted difference 1·09 (−0·65 to 2·83) | 0·22”
Taken as given: The 95% CI is for a mean difference and is two-sided; The p-value is two-sided from a mixed model using a normal approximationMethod: Two-sided p from reported mean difference and 95% CI using pCI with log=0.How we recomputed it: pCI(1.09,-0.65,2.83,0) - CONSISTENTreported p = .850 · recomputed p = .847Reviewer 2Adjusted mean difference in wound pain at 3 months
“Mean adjusted difference −0·58 (−6·45 to 5·30) | 0·85”
Taken as given: The 95% CI is for a mean difference and is two-sided; The p-value is two-sided from a mixed model using a normal approximationMethod: Two-sided p from reported mean difference and 95% CI using pCI with log=0.How we recomputed it: pCI(-0.58,-6.45,5.30,0) - CONSISTENTreported p = .940 · recomputed p = .936Reviewer 2Adjusted mean difference in wound pain at 6 months
“Mean adjusted difference −0·28 (−7·11 to 6·54) | 0·94”
Taken as given: The 95% CI is for a mean difference and is two-sided; The p-value is two-sided from a mixed model using a normal approximationMethod: Two-sided p from reported mean difference and 95% CI using pCI with log=0.How we recomputed it: pCI(-0.28,-7.11,6.54,0) - CONSISTENTreported p = .800 · recomputed p = .802Reviewer 2Adjusted mean difference in wound pain at 12 months
“Mean adjusted difference 1·03 (−7·02 to 9·08) | 0·80”
Taken as given: The 95% CI is for a mean difference and is two-sided; The p-value is two-sided from a mixed model using a normal approximationMethod: Two-sided p from reported mean difference and 95% CI using pCI with log=0.How we recomputed it: pCI(1.03,-7.02,9.08,0)
- mediuminternal contradictionComorbidity percentages in Table 1 use inconsistent denominators; e.g., for NPWT cardiovascular disease, 218/329=66.3%, 111/349=31.8%, and 20/349=5.7% cannot all be true percentages of the same group.
Yes | 218 (66·3%) | 228 (71·9%) | No | 111 (31·8%) | 89 (26·4%) | Missing | 20 (5·7%) | 20 (5·9%)
Table 1reviewer’s wording - mediuminternal contradictionThe abstract reports five usual-care participants with serious adverse events, but Table 3 reports four (1.2%).
“14 were serious (nine participants in the NPWT group and five participants in the usual care group)”
Table 3Find in source - lowinternal contradictionThe numbers of healed and censored participants do not account for all 686 participants: 202+196 healed and 159 censored sum to 557, leaving 129 participants unaccounted for unless they were censored at 12 months without being reported in the censoring sentence.
“wound healing occurred in 202 (57·9%) participants allocated to NPWT, and 196 (58·2%) participants allocated to usual care. 159 (23·2%) participants were censored (83 [23·8%] in the NPWT group and 76 [22·6%] in the usual care group) due to death, amputation, withdrawal, and loss to follow-up”
Results ¶1Find in source - lowinternal contradictionThe text states 14 serious adverse events were reported in nine NPWT and five usual-care participants (summing to 14 participants), but Table 3 reports 9 (2.6%) and 4 (1.2%) participants with at least one serious adverse event (summing to 13).
“14 serious adverse events were reported (nine participants in the NPWT group and five participants in the usual care group)”
Table 3Find in source
Overstated conclusions
None foundConclusions that reach past what the paper's own results support — including a significance claim that no longer holds when the statistic is recomputed, and efficacy resting on an unvalidated surrogate endpoint.
Checked — nothing surfaced.
8 major claims checked against the paper's own evidence: all adequately supported.
- supportedReviewers 1, 2, 3There was no clear evidence that NPWT reduced time to wound healing compared with usual care.The primary analysis directly supports this claim: HR 1.08 (95% CI 0.88–1.32, p=0.47) with overlapping confidence intervals.Evidence: Primary outcome HR 1.08 (95% CI 0.88–1.32), p=0.47; median time 187 vs 195 days.
“There was no clear evidence that NPWT reduced the time to wound healing compared with usual care (hazard ratio 1·08 [95% CI 0·88–1·32], p=0·47).”
AbstractFind in source - supportedReviewers 1, 2, 3These findings do not support the use of NPWT to augment SWHSI healing.The null primary result and consistent secondary outcomes adequately back the conclusion that NPWT offers no healing advantage.Evidence: Null primary outcome plus no statistically significant differences in clinical, patient-reported, or masked-assessment secondary outcomes.
“These findings do not support the use of NPWT to augment SWHSI healing.”
DiscussionFind in source - supportedReviewers 1, 2, 3NPWT was found not to be cost-effective compared with usual care.The within-trial cost-utility analysis reports negative incremental net monetary benefit and <50% probability of cost-effectiveness, supporting the claim despite non-significant QALY/cost increments.Evidence: INMB −£93.22 at £20,000 and −£18.65 at £30,000 thresholds; probability of cost-effectiveness 47.2% and 49.7%.
“NPWT was found not to be cost-effective compared with usual care.”
ResultsFind in source - supportedReviewers 1, 2NPWT should not be considered as a first-line treatment for such patients in relation to wound healing.A reasonable clinical inference from a large, well-powered null trial; the wording is appropriately hedged ('in relation to wound healing').Evidence: Null primary outcome and consistent secondary outcomes in a predominantly lower-limb/diabetic population.
“This finding suggests that NPWT should not be considered as a first-line treatment for such patients in relation to wound healing.”
DiscussionFind in source - supportedReviewer 1The SWHSI-2 trial provides the first robust evaluation of the effectiveness of NPWT, in terms of time to healing, for patients with an SWHSI.The paper documents that prior evidence comprised two small low-quality trials and a meta-analysis of low-quality studies, supporting the claim that this is the first robust evaluation.Evidence: Cited Cochrane review (two small low-quality RCTs) and meta-analysis of 48 low-quality studies.
“the SWHSI-2 trial provides the first robust evaluation of the effectiveness of NPWT as a treatment, in terms of time to healing, for patients with an SWHSI.”
DiscussionFind in source - supportedReviewer 1Despite manufacturers' claims that NPWT promotes wound healing, the findings in our large study do not support this claim.The null primary and secondary results directly contradict the promotional claim and support the authors' conclusion.Evidence: Null primary outcome and consistent secondary outcomes across clinical, patient-reported, and economic endpoints.
“Despite manufacturers' claims that NPWT promotes wound healing, the findings in our large study do not support this claim.”
DiscussionFind in source - supportedReviewer 2SWHSI-2 provides the first robust evaluation of NPWT effectiveness in terms of time to healing for patients with SWHSI.The paper's own account of the prior evidence (two small, low-quality RCTs in a Cochrane review) supports the novelty claim.Evidence: Prior Cochrane review identified only two small, low-quality RCTs; this trial enrolled 686 participants across 29 centres with ITT analysis.
“the SWHSI-2 trial provides the first robust evaluation of the effectiveness of NPWT as a treatment, in terms of time to healing, for patients with an SWHSI”
DiscussionFind in source - supportedReviewer 3The scarcity of previous randomised controlled trial evidence to support NPWT effectiveness has resulted in an ineffective and costly intervention being used in routine care for a considerable period.The paper cites a Cochrane review identifying only two small trials, and the current trial shows no benefit, supporting the claim that prior evidence was insufficient.Evidence: Cochrane review and current trial results.
“The scarcity of previous randomised controlled trial evidence to support NPWT effectiveness has resulted in an ineffective and costly intervention being used in routine care for a considerable period.”
Discussion ¶4Find in source
Data authenticity concerns
1 finding · worst lowAn adversarial read for patterns associated with data that may not be genuine: results that look too clean, implausibly large effects, duplicated data or images, and methods that do not match the results reported.
- Other integrity concernAssessed
5 integrity concerns flagged (0 high).
- lowotherThe Data Availability Statement cites a DOI (10.1016/j.jvs.2013.06.073) that corresponds to a 2013 Journal of Vascular Surgery article, not this trial's repository, and the same erroneous DOI appears in the Associated Data section; the correct repository URL (https://osf.io/echxv) is given elsewhere.
“stored in a publicly available open research repository (10.1016/j.jvs.2013.06.073)”
Data availabilityFind in source
Reporting gaps
3 findings · worst mediumRequired detail the manuscript never states — study design, biological variables, ethics approval and consent, key resources, statistical reporting, data and code availability, and overall transparency.
- Data/code availability incompleteAssessed
- Ethics/consent reporting incompleteAssessed
- Key resources under-identified (antibodies, cell lines, RRIDs)Assessed
The introduction and 'Research in context' cite UK prevalence and cost estimates, document a 23% increase in NPWT use between 2012 and 2014, and cite a Cochrane review that identified only two small, low-quality RCTs. The strengths and weaknesses of prior evidence are acknowledged, and the trial is positioned to address the identified evidence gap.
“median time to healing for these wounds is prolonged at 86 days (95% CI 75–130)”
“A Cochrane systematic review of NPWT for SWHSI identified two small, low-quality randomised controlled trials”
“we aimed to undertake the first robust evaluation of the clinical and cost-effectiveness of NPWT compared with usual care”
“The use of NPWT for SWHSI has increased rapidly in recent years, with a 23% increase in use reported between 2012 and 2014; however, there is absence of robust supporting evidence regarding its clinical effectiveness and cost-effectiveness.”
“The SWHSI-2 trial therefore sought to assess the clinical effectiveness and cost-effectiveness of NPWT compared with usual care (no NPWT) in treating SWHSI.”
“A Cochrane systematic review of NPWT for SWHSI identified two small, low-quality randomised controlled trials”
“The SWHSI-2 trial therefore sought to assess the clinical effectiveness and cost-effectiveness of NPWT compared with usual care (no NPWT) in treating SWHSI.”
Applicable design elements for a human RCT are all adequate: randomisation method and unit are clearly described, open-label design is stated with masked photographic outcome assessment, the sample size calculation is fully specified, and eligibility criteria are detailed. The pre-specified ITT analysis, mean imputation of missing baseline covariates, and right-censoring delimit the analysis population; biological replicate, wet-lab control, and independent replication criteria are not applicable to a human trial.
“Participants and the clinical and research teams were unmasked to treatment allocation. However, to minimise bias, masked assessment of wound healing photographs was completed by clinically experienced independent observers”
“Randomisation to NPWT or usual care (1:1) was stratified by wound location (foot and ankle, leg, abdomen, or other), wound area (<28 cm 2 or ≥28 cm 2 , calculated as the measurement arising from the longest part of the wound multiplied by the measurement for the widest part of the wound), and study centre, using variable block sizes (two, four, six, and eight).”
“Participants and the clinical and research teams were unmasked to treatment allocation. However, to minimise bias, masked assessment of wound healing photographs was completed by clinically experienced independent observers and analysis of this was included as a secondary outcome.”
“Participants and the clinical and research teams were unmasked to treatment allocation. However, to minimise bias, masked assessment of wound healing photographs was completed by clinically experienced independent observers”
Table 1 reports age, gender, ethnicity, smoking status, alcohol consumption, comorbidities, surgical details, wound area, wound location, and number of SWHSIs. Both sexes are represented (76.5% male NPWT, 73.0% male usual care). Species, strain, and housing criteria are not applicable to a human trial.
“Male | 267 (76·5%) | 246 (73·0%)”
“The median participant age was 63 years (IQR 55–72), most participants were male (n=513, 74·8%), and of White ethnicity (n=630, 91·8%).”
“The median participant age was 63 years (IQR 55–72), most participants were male (n=513, 74·8%), and of White ethnicity (n=630, 91·8%).”
“Data are n (%), mean (SD), or median (IQR). NPWT=negative pressure wound therapy. SWHSI=surgical wound healing by secondary intention. WHQ=Bluebelle Wound Healing Questionnaire.”
“most participants were male (n=513, 74·8%)”
“The median participant age was 63 years (IQR 55–72)”
The paper names the ethics committee (Yorkshire and Humber Leeds East Research Ethics Committee) and provides a reference number. Written informed consent is described. However, the paper does not mention adherence to the Declaration of Helsinki or ICH-GCP, which is a minor omission for a clinical trial. Regulatory compliance is therefore considered inadequate.
“The Yorkshire and Humber Leeds East Research Ethics Committee and UK Health Research Authority granted ethical approval (reference 19/YH/0054).”
“Eligible participants were required to give written informed consent.”
“The Yorkshire and Humber Leeds East Research Ethics Committee and UK Health Research Authority granted ethical approval (reference 19/YH/0054).”
“Eligible participants were required to give written informed consent.”
“The trial was registered with ISRCTN, ISRCTN26277546.”
“The Yorkshire and Humber Leeds East Research Ethics Committee and UK Health Research Authority granted ethical approval (reference 19/YH/0054).”
“Eligible participants were required to give written informed consent.”
The paper describes NPWT as a treatment but does not name the manufacturer or specific model used; only that it must be CE-marked and provide 60-150 mm Hg pressure. This is inadequate for reproducibility. Statistical software (R and Stata) is identified with version numbers. Other resource criteria are not applicable for a human trial.
“A specific NPWT model was not prescribed; however, the device was required to be CE marked (ie, meeting legislative requirements for use in the UK and Europe) and to provide 60–150 mm Hg pressure.”
“Statistical analysis was conducted in R (version 4.4.0) and Stata (version 18)”
“A specific NPWT model was not prescribed; however, the device was required to be CE marked (ie, meeting legislative requirements for use in the UK and Europe) and to provide 60–150 mm Hg pressure.”
“Control group participants were randomly assigned to receive routine wound care dressings without NPWT. There is no evidence of any one dressing type or brand being more clinically effective or cost-effective; therefore, primary and secondary dressings, and frequency of change, were determined by the clinical care team.”
“Statistical analysis was conducted in R (version 4.4.0) and Stata (version 18) using two-sided significance tests at the 5% significance level, with parameter estimates presented with associated 95% CI and p values as appropriate.”
“A specific NPWT model was not prescribed; however, the device was required to be CE marked (ie, meeting legislative requirements for use in the UK and Europe) and to provide 60–150 mm Hg pressure.”
“Statistical analysis was conducted in R (version 4.4.0) and Stata (version 18)”
All statistical tests are named (e.g., Cox proportional hazards, mixed-effect logistic regression). Exact p-values are reported for primary and secondary outcomes. Effect sizes are presented with 95% confidence intervals. Software versions are specified. Data presentation includes Kaplan-Meier curves, tables with n and percentages, and appropriate error bars. No arithmetic contradictions were found.
“hazard ratio 1·08 [95% CI 0·88–1·32], p=0·47”
“Statistical analysis was conducted in R (version 4.4.0) and Stata (version 18) using two-sided significance tests at the 5% significance level”
“OR 1·13 (0·76 to 1·69) | 0·54”
“The primary outcome (time to healing of the reference wound) was assessed using a Kaplan–Meier curve by group and the median time to healing and HR with 95% CIs was calculated using a proportional hazards Cox regression model in the coxme package.”
“HR 1·08 (0·88 to 1·32) | 0·47”
“Mean imputation was used to impute 19 (2·8%) missing baseline values for wound area (within the same stratification factor) and three (0·4%) for wound duration (overall mean).”
“The primary outcome (time to healing of the reference wound) was assessed using a Kaplan–Meier curve by group and the median time to healing and HR with 95% CIs was calculated using a proportional hazards Cox regression model”
“OR 1·13 (0·76 to 1·69)”
A data availability statement is present, stating that anonymised data will be stored in an OSF repository (https://osf.io/echxv). This is a concrete repository. However, the data are not yet deposited (only promised), and no code is provided for the statistical analyses. The code sharing is not applicable? The paper uses custom analysis code in R and Stata, but no code is shared. This is a common omission.
“Sharing of this anonymised data is covered by original participant consent for the SWHSI-2 trial, which permits sharing of data to support future research via sharing anonymously.”
“Anonymised datasets generated and analysed during the current study will be stored in a publicly available open research repository (https://osf.io/echxv) .”
“Data will be made available via this repository after completion of analysis and subsequent publication.”
“Anonymised datasets generated and analysed during the current study will be stored in a publicly available open research repository (https://osf.io/echxv) . Data will be made available via this repository after completion of analysis and subsequent publication.”
The methods are comprehensive and reproducible. The trial is registered (ISRCTN26277546). All pre-specified primary and secondary outcomes are reported, including non-significant results. Limitations are discussed in detail. Conclusions are consistent with the null results. Funding and conflicts of interest are stated. The paper does not explicitly cite a reporting guideline, but the structure follows CONSORT (e.g., flow diagram).
“The trial was registered with ISRCTN, ISRCTN26277546.”
“This study was funded by the National Institute for Health Research Health Technology Assessment Programme (project reference 17/42/94).”
“Consideration should also be given to the way in which NPWT use differs between surgical specialities and caution in interpretation of the results might be required when applying these findings to SWHSI not located on the lower limb.”
“The trial was registered with ISRCTN, ISRCTN26277546.”
“This study was funded by the National Institute for Health Research Health Technology Assessment Programme (project reference 17/42/94).”
“Consideration should also be given to the way in which NPWT use differs between surgical specialities and caution in interpretation of the results might be required when applying these findings to SWHSI not located on the lower limb.”
“The trial was registered with ISRCTN, ISRCTN26277546.”
“Consideration should also be given to the way in which NPWT use differs between surgical specialities and caution in interpretation of the results might be required when applying these findings to SWHSI not located on the lower limb.”
“This study was funded by the National Institute for Health Research Health Technology Assessment Programme (project reference 17/42/94).”
Registered (1 ID: ISRCTN). No reporting guideline cited.
Broken references and links
None foundReferences checked against Crossref, OpenAlex and Retraction Watch for retractions and resolvability, plus declared data and code links probed for whether they resolve to content matching the paper.
Checked — nothing surfaced.
Checked 27 references by DOI: 16 verified — 11 no DOI (shown, not verified).
- NO DOIBayesian econometric modelling of observational data for cost-effectiveness analysis: establishing the value of negative pressure wound therapy in the healing of open surgical woundsNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIThe epidemiology, management and impact of surgical wounds healing by secondary intention: a research programme including the SWHSI feasibility RCTNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIUse of vacuum assisted closure therapy in the treatment of diabetic foot woundsNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIThe MUST report: nutritional screening of adults a multidisciplinary responsibility. Development and use of the 'Malnutrition Universal Screening Tool' ('MUST') for adultsNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOINutrition support for adults: oral nutrition support, enteral tube feeding and parenteral nutrition (CG32)No DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIThe measurement and valuation of health status using EQ-5D: a European perspectiveNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIA retrospective study of pilonidal sinus healing by secondary intention using negative pressure wound therapy versus alginate or gauze dressingsNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIcoxme: mixed effects Cox models. R package version 2.2–20No DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIA proportional hazards model for the subdistribution of a competing riskNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIBounds on treatment effects from studies with imperfect complianceNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIHealth technology evaluations: the manual. NICE process and methods (PMG36)No DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
2 data/code links checked; 2 live.
- dataOSFLIVEHTTP 200https://osf.io/echxvResolves to OSF (data repository).
- datahttps://www.isrctn.com/ISRCTN26277546LIVEHTTP 200Resolved page looks like data.
Copyediting
1 finding · worst lowWording, consistency and formatting errors that need correcting before submission.
- Wording or formatting errors that need correctingAssessed
11 copyedit issues flagged (4 major): mostly consistency, other, clarity.
- MAJORconsistencyResults, Adverse events vs Table 3“14 serious adverse events were reported (nine participants in the NPWT group and five participants in the usual care group)”→ Align the text with Table 3, which reports 9 and 4 participants with at least one serious adverse event; clarify the number of events versus participants.Text implies 14 participants (9+5) while the table sums to 13 participants with at least one SAE.
- MAJORconsistencyAbstract vs Table 3“14 were serious (nine participants in the NPWT group and five participants in the usual care group)”→ Reconcile the number of usual-care participants with serious adverse events: Table 3 reports 4 (1.2%).Abstract and Table 3 disagree on the number of usual-care participants with at least one serious adverse event.
- MAJORconsistencyTable 1, Comorbidities“Yes | 218 (66·3%) | 228 (71·9%) | No | 111 (31·8%) | 89 (26·4%) | Missing | 20 (5·7%) | 20 (5·9%)”→ Recalculate percentages with a single denominator per group; the current values mix denominators (e.g., 218/329=66.3% but 111/349=31.8%).Yes/No/Missing percentages do not share a consistent denominator and do not sum to 100%.
- MAJORconsistencyAssociated Data / Data Availability Statement“Anonymised datasets ... repository (10.1016/j.jvs.2013.06.073)”→ Replace the unrelated JVS DOI with the correct OSF repository URL (https://osf.io/echxv) or a proper dataset DOI.The DOI listed in the Associated Data section appears to be from a journal article, not the OSF repository.
- MINORconsistencyData Availability Statement / Associated Data“stored in a publicly available open research repository (10.1016/j.jvs.2013.06.073)”→ Replace the journal-article DOI with the OSF repository identifier (https://osf.io/echxv) or the dataset's own DOI.DOI 10.1016/j.jvs.2013.06.073 is a 2013 Journal of Vascular Surgery article, not this trial's dataset.
- MINORotherEnd of Article / Acknowledgments“Contribu”→ Complete the truncated contributor/CRediT text.The manuscript ends abruptly with 'Contribu' and has a duplicated 'Acknowledgments' heading.
- MINORclarityResults, paragraph 2“The primary analysis found a small non-statistically significant reduction (8%) in the time to healing in the NPWT group”→ Clarify that an HR of 1.08 corresponds to an 8% higher healing hazard (shorter time) and that the difference in median time was 8 days.The '8%' figure is ambiguous without reference to the HR being above 1.0.
- MINORclarityResults, censoring sentence“159 (23·2%) participants were censored (83 [23·8%] in the NPWT group and 76 [22·6%] in the usual care group) due to death, amputation, withdrawal, and loss to follow-up”→ State the number of participants unhealed at 12 months and whether they are included in the censoring count.398 healed + 159 censored = 557, leaving 129 participants unaccounted for unless they were censored at 12 months without being mentioned.
- MINORtypoResearch in context / Evidence before this study“identified two, small, low-quality randomised controlled trials, , , , , and recommended caution”→ Insert the missing citation numbers in place of the empty commas.Empty reference placeholders appear in the Research in context panel.
- MINORotherAuthor list“SWHSI-2 Trial Investigators on behalf of the a York Trials Unit”→ Remove the extra 'a' before 'York Trials Unit'.
- MINORconsistencyResearch in context“The text in 'Evidence before this study' largely repeats the Introduction.”→ Consider condensing the 'Research in context' section to avoid redundancy with the Introduction.This may be a requirement of the journal format.
Post-publication, the trial's core methodology and null conclusion are robust and supported by consistent verified statistics; the primary findings should be trusted. However, an informed reader should weigh the reporting gaps (no named regulatory-framework statement, generically identified NPWT device, data not yet deposited and no shared code) and the internal inconsistencies in SAE counts, Table 1 percentages, and censoring accounting, which are appropriate subjects for an erratum or author clarification rather than a fundamental re-analysis.
- 1.HIGHstatisticsReconcile the serious adverse event counts: the Abstract and Results state nine NPWT and five usual-care participants (14 total) while Table 3 reports 9 (2.6%) and 4 (1.2%) (13 total); correct the text, abstract, and table to agree and clarify events vs participants.This is a verifiable internal contradiction that a reader will flag and that should be corrected via erratum.
- 2.HIGHstatisticsRecalculate the Table 1 comorbidity percentages with a single consistent denominator per group (e.g., full group N), fixing entries such as NPWT cardiovascular-disease 'Yes 218 (66·3%) / No 111 (31·8%) / Missing 20 (5·7%)' that mix denominators and do not sum to 100%.Inconsistent denominators in baseline tables are an internal contradiction that undermines the reliability of reported baseline data.
- 3.HIGHdata codeReplace the erroneous DOI '10.1016/j.jvs.2013.06.073' (a 2013 Journal of Vascular Surgery article) in the Data Availability Statement and Associated Data with the correct OSF repository URL (https://osf.io/echxv) or a DOI assigned to the dataset.The current DOI points to an unrelated publication and would misdirect readers seeking the trial data.
- 4.HIGHstatisticsClarify the censoring accounting in Results, paragraph 2: 202+196 healed and 159 censored sum to 557, leaving 129 participants unaccounted for; state how many were unhealed but censored at 12 months and report censoring by reason.The numbers as reported do not sum to the trial population of 686, an internal inconsistency affecting interpretation of the KM analysis.
- 5.HIGHdata codeDeposit the anonymised dataset in the OSF repository (https://osf.io/echxv) now and provide a stable DOI/accession, rather than stating data 'will be made available' after publication.A data availability statement that only promises future deposit and lacks a persistent identifier is not yet a usable data-sharing commitment.
- 6.HIGHdata codeProvide the statistical analysis code (R and Stata scripts) used for the primary and economic analyses in a public repository (or state explicitly why it cannot be shared).Sharing analysis code materially strengthens reproducibility of a published trial and is currently absent.
- 7.HIGHethicsAdd an explicit statement of adherence to a named regulatory framework (Declaration of Helsinki or ICH-GCP) to the ethics/compliance section.The paper names the ethics committee and consent but does not state compliance with a recognised framework, which several reviewers identified as a gap.
- 8.HIGHrigorSpecify the NPWT device model(s) and manufacturer(s) actually used (or, if the pragmatic design intentionally avoids prescribing a model, state this explicitly as a resource-identification rationale in Methods, Procedures) and describe usual-care dressing types and change frequencies.Generic identification of the investigational product and comparator dressing limits reproducibility of the intervention.
- 9.HIGHreportingCite the CONSORT 2010 reporting checklist and note adherence (the trial-profile figure is CONSORT-style but no checklist is referenced).An explicit reporting-guideline citation is a standard transparency expectation for a published RCT.
- 10.MEDIUMcopyeditClarify in Results, paragraph 2 that an HR of 1.08 corresponds to an 8% higher healing hazard (shorter time) and that the difference in median time-to-healing was 8 days, rather than the ambiguous 'small non-statistically significant reduction (8%)'.The current phrasing is ambiguous about the direction and magnitude of the effect.
- 11.MEDIUMcopyeditComplete the truncated 'Contribu' text at the end of the contributors section and remove the duplicated 'Acknowledgments' heading.The manuscript ends abruptly with an incomplete contributor statement and a duplicated heading, visible production defects.
- 12.MEDIUMcopyeditInsert the missing citation numbers in the Research in context / 'Evidence before this study' panel where empty commas appear ('two, small, low-quality randomised controlled trials, , , , ,').Empty reference placeholders are a formatting error that obscures the cited prior work.
- 13.MEDIUMcopyeditRemove the stray 'a' before 'York Trials Unit' in the author affiliation (''SWHSI-2 Trial Investigators on behalf of the a York Trials Unit').The extra article is a typographical error in the author list.
- 14.MEDIUMrigorReport participant weight or BMI if the data are available in the trial dataset.Weight is not a standard variable for this trial but would fully satisfy the age/weight/health reporting criterion flagged by one reviewer.
- 15.LOWdata codeShare the full statistical analysis plan (SAP) alongside the data and code, since it is currently only referenced via the trial registry.Making the SAP directly available with the paper strengthens the audit trail for the pre-specified analysis.
- 16.LOWcopyeditConsider condensing the 'Research in context' section where it largely repeats the Introduction.Redundancy between the two sections is a readability issue (though possibly required by journal format).
The star rating is the report’s one-glance summary. Every paper starts at 5★ and loses stars for the concrete problems the review finds — so a rating is never a vague average, it’s a running total you can read line by line under “How this rating was calculated.”
- Reporting — 8 dimensionseach dimension that fully fails−½★
- each dimension partially met−¼★
- Statistics · Integrity · Claimseach serious problem−1★
- each medium problem−½★
- Citationseach retracted or unverifiable reference−¼★
- Copyeditonly when the manuscript needs a full edit−½★
The rating never drops below 1★, and a demonstrable critical failure (an impossible statistic, a proven ethics violation) caps it at 1★ on its own — so the stars can never look healthy when the verdict is CRITICAL.
The rating draws on a panel of agents. Three independent Kaimen Rigor reviewers grade the eight dimensions below across several independent passes (the shown verdict is their majority vote — steadier than any single run), isolate the paper’s major claims and check its own evidence backs them, and flag integrity concerns. Alongside them, a citation agent resolves every reference against Crossref, OpenAlex, and Retraction Watch; a statistics agent recomputes reported tests; and rule-based checks verify that declared data/code links actually resolve. Full text is required — an abstract-only submission is not analyzed.
Graded against NIH, MDAR, ARRIVE 2.0, CONSORT, EQUATOR, and RRID guidelines. A dimension that doesn’t apply to the study type is skipped, never penalized.
This Kaimen Rigor review is model-assisted and is not a substitute for formal expert review. It complements human evaluation by surfacing potential methodological concerns — verify each finding against the source.