Article type
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Abstract
Background: Systematic reviews seek to minimize bias in assessing the effects (intended and unintended) of interventions, to provide people making healthcare decisions with a balanced account of the likely outcomes.
Objectives: To assess how information about adverse events is included in systematic reviews.
Methods: We used Issue 1, 2005 of The Cochrane Library to assess all 79 new Cochrane reviews in that issue of The Cochrane Database of Systematic Reviews (CDSR) and all 89 reviews from 2003-2004 in the Database of Abstracts of Reviews of Effects (DARE). Data were extracted on: area of health care; type of intervention; study design; type of search; study quality; method of analysis. We excluded reviews published in a language other than English (DARE (4)) and those of screening or diagnostic test accuracy (CDSR (1)); (DARE (6)).
Results: Fifty-nine percent of both Cochrane (46/78) and DARE (47/79) reviews assessed drug interventions. The rest assessed: surgery (Cochrane (10); DARE (10)); psychosocial / education (9;14); physiotherapy (5;1); and other (8;7). Seventy-six percent (59/78) of Cochrane reviews mentioned adverse events as an outcome compared with 48% (38/79) of DARE reviews. Most were of drug interventions (Cochrane (43/59); DARE (29/38)). For the reviews which mentioned adverse events, 93% (55/59) of Cochrane reviews included only randomized trials and 73% (43/59) included an analysis of adverse events. For 10 Cochrane reviews, adverse events had not been reported by the included trials, and no trials were included for six. In contrast, 58% (22/38) of DARE reviews included only randomized trials, the rest included both randomized and non-randomized studies. All but one of these included analysis of adverse events.
Conclusions: Most Cochrane reviews of drug interventions considered adverse events. This was not the case for DARE reviews and Cochrane reviews of non-drug interventions and could be improved.
Objectives: To assess how information about adverse events is included in systematic reviews.
Methods: We used Issue 1, 2005 of The Cochrane Library to assess all 79 new Cochrane reviews in that issue of The Cochrane Database of Systematic Reviews (CDSR) and all 89 reviews from 2003-2004 in the Database of Abstracts of Reviews of Effects (DARE). Data were extracted on: area of health care; type of intervention; study design; type of search; study quality; method of analysis. We excluded reviews published in a language other than English (DARE (4)) and those of screening or diagnostic test accuracy (CDSR (1)); (DARE (6)).
Results: Fifty-nine percent of both Cochrane (46/78) and DARE (47/79) reviews assessed drug interventions. The rest assessed: surgery (Cochrane (10); DARE (10)); psychosocial / education (9;14); physiotherapy (5;1); and other (8;7). Seventy-six percent (59/78) of Cochrane reviews mentioned adverse events as an outcome compared with 48% (38/79) of DARE reviews. Most were of drug interventions (Cochrane (43/59); DARE (29/38)). For the reviews which mentioned adverse events, 93% (55/59) of Cochrane reviews included only randomized trials and 73% (43/59) included an analysis of adverse events. For 10 Cochrane reviews, adverse events had not been reported by the included trials, and no trials were included for six. In contrast, 58% (22/38) of DARE reviews included only randomized trials, the rest included both randomized and non-randomized studies. All but one of these included analysis of adverse events.
Conclusions: Most Cochrane reviews of drug interventions considered adverse events. This was not the case for DARE reviews and Cochrane reviews of non-drug interventions and could be improved.
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