The higher quality, the more convincing: a cross-sectional study of randomized controlled human trials on drug safety

Tags: Poster
Zhang L1, Chen Q2, Zhao P1, Jia P1, Zhang M1
1Chinese Evidence-Based Medicine Centre, West China Hospital, Sichuan University, China, 2West China School of Public Health, Sichuan University , China

Background: Can drug safety analyses in randomized controlled trials answer drug safety issues accurately? Regrettably, for much research the answer is no. Findings from drug safety analyses may be misleading, potentially resulting in clinical threat and health decision making. Few studies have investigated the reporting and conduct of drug safety analyses and a number of important questions remain unanswered.

Objectives: To describe the methodological quality of drug safety research in randomized controlled trials with a modified version of the Cochrane 'Risk of bias' (RoB) tool.

Methods: We conducted a cross-sectional study of 165 eligible randomized controlled human trials on drug safety, which we randomly selected from MEDLINE, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL) in 2014. Teams of two reviewers independently screened full texts of reports for eligibility, and abstracted data, using standardized, pilot-tested extraction forms. We assessed the risk of bias in these studies According to a modified version of the Cochrane RoB tool (we considered random sequence generation; allocation concealment; blinding of participants, caregivers, and outcome assessors; adjudication of adverse events; prognostic balance between treatment groups; and incomplete outcome data). We conducted a statistical analysis to describe current situation about the methodological quality of drug safety research in randomized controlled trials.

Results: Within these studies, only 20% specifically mentioned the randomized method, but 77% mentioned randomization without specifying methods. Similar results appeared for allocation concealment; patients and caregivers were blinded in 48%, but outcome assessors in only 24%. There were few studies that made judgements of adverse events.

Conclusions: Currently, qualities of randomized controlled trials about drug safety research are uneven. Research of high quality with sufficient reports can get more approvals. Our findings will contribute to a set of recommendations to optimize the conduct and reporting of drug safety analysis.