Negative Pressure Wound Therapy vs Conventional Wound Treatment in Subcutaneous Abdominal Wound Healing Impairment: The SAWHI Randomized Clinical Trial

Abstract

Importance: Negative pressure wound therapy (NPWT) is an established treatment option, but there is no evidence of benefit for subcutaneous abdominal wound healing impairment (SAWHI).

Objective: To evaluate the effectiveness and safety of NPWT for SAWHI after surgery in clinical practice.

Design, setting, and participants: The multicenter, multinational, observer-blinded, randomized clinical SAWHI study enrolled patients between August 2, 2011, and January 31, 2018. The last follow-up date was June 11, 2018. The trial included 34 abdominal surgical departments of hospitals in Germany, Belgium, and the Netherlands, and 539 consecutive, compliant adult patients with SAWHI after surgery without fascia dehiscence were randomly assigned to the treatment arms in a 1:1 ratio stratified by study site and wound size using a centralized web-based tool. A total of 507 study participants (NPWT, 256; CWT, 251) were assessed for the primary end point in the modified intention-to-treat (ITT) population.

Interventions: Negative pressure wound therapy and conventional wound treatment (CWT).

Main outcomes and measures: The primary outcome was time until wound closure (delayed primary closure or by secondary intention) within 42 days. Safety analysis comprised the adverse events (AEs). Secondary outcomes included wound closure rate, quality of life (SF-36), pain, and patient satisfaction.

Results: Of the 507 study participants included in the modified ITT population, 287 were men (56.6%) (NPWT, 155 [60.5%] and CWT, 132 [52.6%]) and 220 were women (43.4%) (NPWT, 101 [39.5%] and CWT 119 [47.4%]). The median (IQR) age of the participants was 66 (18) years in the NPWT arm and 66 (20) years in the CWT arm. Mean time to wound closure was significantly shorter in the NPWT arm (36.1 days) than in the CWT arm (39.1 days) (difference, 3.0 days; 95% CI 1.6-4.4; P < .001). Wound closure rate within 42 days was significantly higher with NPWT (35.9%) than with CWT (21.5%) (difference, 14.4%; 95% CI, 6.6%-22.2%; P < .001). In the therapy-compliant population, excluding study participants with unauthorized treatment changes (NPWT, 22; CWT, 50), the risk for wound-related AEs was higher in the NPWT arm (risk ratio, 1.51; 95% CI, 0.99-2.35).

Conclusions and relevance: Negative pressure wound therapy is an effective treatment option for SAWHI after surgery; however, it causes more wound-related AEs.

Trial registration: ClinicalTrials.gov Identifier: NCT01528033.

Conflict of interest statement

Conflict of Interest Disclosures: Ms Seidel reported grants from Kinetic Concepts Incorporated (KCI), an Acelity company, during the conduct of the study; other support from Smith & Nephew Honoraria for lectures, grants from Smith & Nephew, KCI, and from German statutory health insurance funds (AOK-Bundesverband, Verband der Ersatzkrankenkassen (vdek), Knappschaft) outside the submitted work. Drs Diedrich, Herrle, Thielmann, Marusch, Schirren, Talaulicar, Gehrig, Tyquschik, Glanemann, Bunse, Hüttemann, Heizmann Miserez, Gretschel, Lefering, reported grants from the Institute for Research in Operative Medicine (Witten/Herdecke University) and received compensation for traveling to investigator meetings during the conduct of the study. Prof Marusch reported personal fees from Coloplast Lectures outside the submitted work. Dr Schirren reported other support from KCI (an Acelity company) outside the submitted work. Dr Bunse reported other financial support from Acelity outside the submitted work; and membership in the German Wound Healing Society. Dr Braumann reported personal fees from KCI (an Acelity company) outside the submitted work. Dr Kroenert reported grants from Institute for Research in Operative Medicine (Witten/Herdecke University) during the conduct of the study. Dr Lefering reported grants from KCI (an Acelity company) and grants from Smith & Nephew and German statutory health insurance funds (AOK-Bundesverband, Verband der Ersatzkassen [vdek]) outside the submitted work.

Figures

Figure 1.. Study Participant Flow in the Subcutaneous Abdominal Wound Healing Impairment (SAWHI) Randomized Clinical Trial

Patient flow according to Consolidated Standards of Reporting Trials (CONSORT), including all reasons for exclusions from the intention-to-treat (ITT) and the per protocol (PP) population. CWT indicates conventional wound treatment; EOMTT, end of maximum treatment time; NPWT indicates negative pressure wound therapy; WC, wound closure.

Figure 2.. Time to Wound Closure in the Intention-to-Treat (ITT) Population

Starting point of the presentation are 100% open wounds on the day of randomization/initiation of the study therapy (negative pressure wound therapy [NPWT] or conventional wound treatmen [CWT]). Kaplan-Meier curves are used to show the decrease in the number of open wounds within the study treatment/observation period of 42 days. The number of study participants at risk (with open wounds) is shown below the diagram for each survey time (randomization/initiation of therapy and weekly study visits) and the end of the maximum treatment time after 42 days. The course was censored for each study participant if this participant achieved the study goal complete, verified, and sustained wound closure. Mean time to wound closure is shown in days for each treatment arms and as difference between the treatment arms together with 95% CI. Mean time to wound closure was compared between the treatment arms using the log-rank test.