Background:

The use of unpublished data and abstract publications in decision-making procedures in health care is inconsistent. The German Institute for Quality and Efficiency in Health Care (IQWiG) conducted a systematic review on negative pressure wound therapy (NPWT).

Objectives:

In the context of this review, our objective was to obtain a comprehensive overview of studies on NPWT.

Methods:

A database search was performed in MEDLINE, EMBASE, CINAHL and the Cochrane Central Register of Controlled Trials
(CENTRAL). In this primary search, only six small randomized controlled trials (RCTs) of poor quality were identified. An additional search was therefore conducted to find unpublished studies. Publications identified in the primary search, such as congress abstracts, online trial registers, and systematic reviews, were further analysed. Authors and sponsors were asked to supply additional details on the studies.

Results:

Nineteen unpublished studies including a planned number of 1834 patients were identified and analysed; 11 of these trials were sponsored by a manufacturer. Overview of studies - Study status: No. of trials (No. sponsored by a manufacturer) / No. of planned patients. I: Completed 3 (1) / n = 108. II: Ongoing 7 (5) / n = 900. III: Unclear 4 (0) / n = not specified. IV: Discontinued: 5 (5) / n = 826. In general, replies raised new unanswered questions rather than resolving the original issues. One ongoing relevant RCT was identified, and after completion of the trial the results were added to the body of evidence.

Conclusions:

An additional search for unpublished studies may identify recently completed trials. The large number of unpublished trials on NPWT raises doubts about the overall validity of published results.