Some improvements are apparent in identifying adverse effects in systematic reviews from 1994 to 2011

Abstract

Objective: An increasing amount of research and guidelines has been published on search methodology and the reporting of search strategies in systematic reviews. This research assessed whether this has lead to any improvements in the reporting and quality of searching in systematic reviews of adverse effects.

Study design and setting: All records within Cochrane Database of Systematic Reviews and Database of Abstracts of Reviews of Effects were scanned for systematic reviews of adverse effects. Data were then extracted on the methods used for information retrieval in these reviews and a descriptive analysis conducted by publication year.

Results: A total of 849 reviews published from 1994 to 2011 met the inclusion criteria. There has been a significant increase (P<0.001) in the number of adverse effects reviews per year from 1994 (n=5) to 2010 (n=104). Some improvements were apparent, such as an increase in the number of databases searched and fewer date and language restrictions applied. However, there has been an increase in reviews limited to data from randomized controlled trials, whereas the reporting of search strategies could still be improved further, with only 9% (74/849) of the reviews reporting reproducible searches.

Conclusion: Some improvements in searching systematic reviews of adverse effects are apparent; however, poor reporting of search strategies remains a great obstacle to readers.