Poor reporting and inadequate searches were apparent in systematic reviews of adverse effects

Objective: Systematic reviews incorporating adverse effects are assuming increasing importance as questions raised extend beyond clinical effectiveness to all effects (beneficial and harmful). The aim of this study was to survey the methods used to identify relevant studies for systematic reviews of adverse effects. Study Design and Setting: All records within the Database of Abstracts of Reviews of Effects and the Cochrane Database of Systematic Reviews were scanned for systematic reviews in which the primary outcomes were adverse effects. Two information professionals independently assessed the methods used to identify relevant research as reported in the 277 reviews that met the inclusion criteria. Results: A major weakness of the reviews was inadequate reporting of the search strategies used. In addition, of the reviews that did report a search strategy, few used the sensitive search strategies recommended for systematic reviews. The majority of reviews did not search more than one or two databases, and few other methods of identifying information were used. Conclusion: This investigation shows the variation in the searching element of systematic reviews of adverse effects and demonstrates that the reporting of the methods used to identify research in such reviews could be vastly improved. (c) 2008 Elsevier Inc. All rights reserved.