Article type
Year
Abstract
Background: Systematic reviews on similar topics may be based on data from different primary studies. The German Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen; IQWiG) conducted a systematic review on negative pressure wound therapy (NPWT).
Objectives: The aim of this analysis was to compare retrospectively the practice of study classification and study inclusion in different systematic reviews on NPWT.
Methods: A multi-source literature search to identify primary studies and systematic reviews on NPWT was performed in the bibliographic databases MEDLINE, EMBASE, The Cochrane Library, and CINAHL. All databases were searched from inception to May 2005. Only publicly accessible full-text publications were considered. Eligible systematic reviews had to include data from completed primary studies on NPWT. In order to ensure an identical study pool and comparability between reviews, reviews published before December 2003 were excluded. Furthermore, only primary studies published before June 2003 (at least 6 months before publication of the oldest systematic review in the analysis) were considered.
Results: A total of 5 systematic reviews (including the IQWiG review) were identified and analysed. Two reviews only considered randomised controlled trials (RCTs). Three reviews (including the IQWiG review) considered both RCTs and non-randomised studies (NRSs) but the IQWiG review only included NRSs with a concurrent control group. The 5 reviews identified a total of 11 primary studies. However, only 3 studies were identified by all reviews. The design of 2 studies was classified differently (either as a RCT or a NRS). One Russian study was classified as an RCT on NPWT by one systematic review. However, a translation of the full text by IQWiG showed that the intervention was not a technique comparable to NPWT; IQWiG therefore did not include this study in its review.
Conclusions: Systematic reviews do not consistently identify the available study pool on NPWT. Furthermore, the practice of study classification and study inclusion varies considerably between reviews. Harmonisation of search strategies and inclusion criteria for studies, as well as adherence to methodological standards, are necessary to decrease variability between systematic reviews.
Objectives: The aim of this analysis was to compare retrospectively the practice of study classification and study inclusion in different systematic reviews on NPWT.
Methods: A multi-source literature search to identify primary studies and systematic reviews on NPWT was performed in the bibliographic databases MEDLINE, EMBASE, The Cochrane Library, and CINAHL. All databases were searched from inception to May 2005. Only publicly accessible full-text publications were considered. Eligible systematic reviews had to include data from completed primary studies on NPWT. In order to ensure an identical study pool and comparability between reviews, reviews published before December 2003 were excluded. Furthermore, only primary studies published before June 2003 (at least 6 months before publication of the oldest systematic review in the analysis) were considered.
Results: A total of 5 systematic reviews (including the IQWiG review) were identified and analysed. Two reviews only considered randomised controlled trials (RCTs). Three reviews (including the IQWiG review) considered both RCTs and non-randomised studies (NRSs) but the IQWiG review only included NRSs with a concurrent control group. The 5 reviews identified a total of 11 primary studies. However, only 3 studies were identified by all reviews. The design of 2 studies was classified differently (either as a RCT or a NRS). One Russian study was classified as an RCT on NPWT by one systematic review. However, a translation of the full text by IQWiG showed that the intervention was not a technique comparable to NPWT; IQWiG therefore did not include this study in its review.
Conclusions: Systematic reviews do not consistently identify the available study pool on NPWT. Furthermore, the practice of study classification and study inclusion varies considerably between reviews. Harmonisation of search strategies and inclusion criteria for studies, as well as adherence to methodological standards, are necessary to decrease variability between systematic reviews.