Negative pressure wound therapy in patients with wounds healing by secondary intention: a systematic review and meta-analysis of randomised controlled trials.

Background: Negative pressure wound therapy (NPWT) is a widely used method of wound treatment. We performed a systematic review of randomised controlled trials (RCTs) comparing the patient-relevant benefits and harms of NPWT with standard wound therapy (SWT) in patients with wounds healing by secondary intention.

Methods: We searched for RCTs in MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, and study registries (last search: July 2018) and screened reference lists of relevant systematic reviews and health technology assessments. Manufacturers and investigators were asked to provide unpublished data. Eligible studies investigated at least one patient-relevant outcome (e.g. wound closure). We assessed publication bias and, if feasible, performed meta-analyses, grading the results into different categories (hint, indication or proof of a greater benefit or harm).

Results: We identified 48 eligible studies of generally low quality with evaluable data for 4315 patients and 30 eligible studies with missing data for at least 1386 patients. Due to potential publication bias (proportion of inaccessible data, 24%), we downgraded our conclusions. A meta-analysis of all wound healing data showed a significant effect in favour of NPWT (OR 1.56, 95% CI 1.15 to 2.13, p = 0.008). As further analyses of different definitions of wound closure did not contradict that analysis, we inferred an indication of a greater benefit of NPWT. A meta-analysis of hospital stay (in days) showed a significant difference in favour of NPWT (MD - 4.78, 95% CI - 7.79 to - 1.76, p = 0.005). As further analyses of different definitions of hospital stay/readmission did not contradict that analysis, we inferred an indication of a greater benefit of NPWT. There was neither proof (nor indication nor hint) of greater benefit or harm of NPWT for other patient-relevant outcomes such as mortality and adverse events.

Conclusions: In summary, low-quality data indicate a greater benefit of NPWT versus SWT for wound closure in patients with wounds healing by secondary intention. The length of hospital stay is also shortened. The data show no advantages or disadvantages of NPWT for other patient-relevant outcomes. Publication bias is an important problem in studies on NPWT, underlining that all clinical studies need to be fully reported.