Trends in recruitment of women and reporting of sex differences in large-scale published randomized controlled trials in stroke.

Background: Understanding of sex differences, especially in terms of the influence of sex on therapeutic interventions, can lead to improved treatment and management for all.

Aim: We examined temporal and regional trends in female participation and the reporting of sex differences in stroke randomized controlled trials.

Methods: Randomized controlled trials from 1990 to 2018 were identified from ClinicalTrials.gov, using keywords "stroke" and "cerebrovascular accidents." Studies were selected if they enrolled ≥100 participants, included both sexes and were published trials (identified using PubMed, Google Scholar, and Scopus).

Results: Of 1700 stroke randomized controlled trials identified, 277 were published and eligible for analysis. Overall, these randomized controlled trials enrolled only 40% females, and in the past 10 years, this percentage barely changed, peaking at 41% in 2008-2009 and 2012-2013. North American randomized controlled trials recruited the most women, at 43%, and Asia the lowest, at 40%. Among the 277 randomized controlled trials, 101 (36%) reported results according to sex, of which 91 (33%) were pre-specified analyses. The increasing trend in the number of studies reporting sex-differentiated results from 2008 to 2018 merely paralleled the increase in the number of papers published during the same time period. North American randomized controlled trials most often reported sex-specific results (42%), and Australia and Europe least often (31%).

Conclusion: Little progress has been made in the inclusion of females and the reporting of sex in stroke randomized controlled trials. This highlights the need for key stakeholders, such as funders and journal editors, to provide clear guidance and effective implementation strategies to researchers in the scientific reporting of sex.