Reporting of adverse events, conflict of interest and funding in randomised controlled trials of antibiotics: a secondary analysis

OBJECTIVES: Transparent reporting of trials is necessary to assess their internal and external validity. Currently, little is known about the quality of reporting in antibiotics trials. Our study investigates the reporting of adverse events, conflicts of interest and funding information in trials of penicillins, cephalosporins and macrolides. DESIGN: A secondary analysis of trials included in a convenience sample of three systematic reviews. METHODS: All randomised controlled trials included in the systematic reviews were included, although duplicates were removed. Eligible trials compared the specified antibiotics to placebo, for any indication. Author pairs independently extracted the data on reporting of adverse events from parent reviews, and data on funding and conflict of interest information from the trial reports. We calculated the overall proportion of trials reporting adverse events, conflict of interest information and funding information, and their proportion before and after the publication of the Consolidated Standards of Reporting Trials (CONSORT) 2001 Statement. RESULTS: We included 432 trials. Overall, 62% of trials reported adverse events of any kind, although reporting of deaths or antibiotic resistance was less frequent (20% and 37%, respectively). Conflict-of-interest information was provided in 26% of the trials, and funding information was provided in 66% of the trials. There was no significant difference in reporting of adverse events before and after the publication of CONSORT 2001 Statement (62% vs 62%, p=0.92). Conflict of interest statements were provided more frequently (2% vs 55%, p<0.001) and conflict was present more often (0% vs 14%, p<0.001). There was no difference in the provision of the information about trial funding before (62%) and after (70%) CONSORT 2001 publication. CONCLUSIONS: Information about adverse events, conflict of interest and funding, remains under-reported in trials of antibiotics.