Reporting adverse events in randomized controlled trials

Purpose How randomized controlled trial results are reported may minimize concerns and detection of adverse side effects. We aimed to describe the methods of reporting adverse events in these published trials. Methods Five frequently cited journals were investigated: Annals of Internal Medicine, British Medical Journal, JAMA, The Lancet, and the New England Journal of Medicine. For each journal, all randomized controlled trials conducted on the use of a medication were selected from January 2000 through June 2003. All issues of each journal were reviewed manually. Information retrieved included any mention of adverse events in the abstract, methods, results, or discussion section of the article; or inclusion of adverse events data in tables or figures. We also cataloged whether there was a separate subheading in the results section for reporting adverse events. Reports of trials that referred to methods described in a previous report were excluded. Results There were 521 eligible articles. Explicit mention of adverse events was in 328 (63%) of abstracts (range 47-66%), 380 (73%) of methods (range 51-81%), 464 (89%) of results (range 80-95%), and 250 (48%) of tables (range 31-49%). There was a separate subheading for adverse events in 240 (46%) (range 22-64%) of the eligible articles. Conclusion There is variation among authors and journals as to the location of reporting adverse events and the means by which it is done. Authors and editors should include specific information on adverse events when reporting the results of randomized controlled trials. It would be ideal if there was more consistency among authors and journals as to how these adverse events are described. Copyright (c) 2006 John Wiley & Sons, Ltd.