Female participation, and sex-specific reporting practices, in polypill randomized controlled trials in the prevention of atherosclerotic cardiovascular disease: a secondary analysis of a systematic review

Aims The polypill is an emerging strategy for the prevention and management of cardiovascular disease (CVD). We assessed the participation of females in randomized controlled trials evaluating polypills for prevention of CVD and subsequent sex-specific analyses and reporting. Methods and results Cardiovascular polypill trials were identified through a systematic review. Data were extracted on the use of sex-specific eligibility criteria, female participation, and the conduct, findings, and interpretation of sex-specific analyses. Of 26 trials included, 12 (46%) excluded groups of females, mainly if pregnant or lactating or of childbearing potential. Female participation ranged from 10% to 73% across trials. Overall, 42% of included participants were female. Of 18 trials conducted in a mostly primary prevention population, females represented 49% of trial participants. In mixed or exclusively secondary prevention trials (n = 8), females represented 26% of trial participants. Females represented 46% of trial participants in trials that excluded groups of females (n = 12). In trials without explicit exclusion criteria (n = 13), females represented 32% of trial participants. Nine out of 26 trials reported sex-stratified analyses (35% of trials; 70% of all participants). Of these, two found some evidence for possible sex differences, both reporting larger blood pressure effects in females than males. Four trials provided sex considerations in the discussion section of the report. Conclusion The participation of females in cardiovascular polypill trials is substantially higher in primary prevention trials as compared with trials conducted in mixed or exclusively secondary prevention populations. The use of sex-specific eligibility criteria was not linked to lower female participation. Sex-specific reporting is sparsely conducted, although most frequent in larger trials.