Abstract 28: The Representation of Women in Randomized Clinical Trials of Acute Stroke (2010-2020)

Abstract

Introduction: The inadequate enrollment of women in RCTs represents a threat to trial generalizability and potential inequities in access to novel treatments. We sought to determine whether women were under-enrolled in contemporary acute stroke trials. Methods: We searched MEDLINE for completed RCTs published in one of nine major journals between 2010 and 2020. Eligible studies were phase 2 or 3 trials undertaken to test therapeutic interventions within one month of stroke onset. For each trial we calculated the proportion of trial participants that were women (PPW). We used Global Burden of Disease (GBD) data to estimate the expected proportion of strokes occurring in women in the underlying stroke populations (PSW). We matched individual estimates from the GBD data to each trial based on geographic location, year, and stroke type. To quantify disparities, we calculated the enrollment disparity difference (EDD), defined as EDD = PSW - PPW. A positive EDD indicates that women were under-represented in the trial. We used random effects meta-analysis to pool individual EDDs and conducted subgroup analyses. Results: We identified 115 trials that met eligibility criteria. The random effects summary EDD was 0.053 (95% CI = 0.040, 0.053), indicating that women were under-enrolled in acute stroke trials by 5% relative to their representation in the underlying stroke population. However, there was substantial between-trial variability in the EDD (I 2 =84.4%). In subgroup analyses, the EDD was similar across subgroups except for stroke type (figure); trials that only included subarachnoid hemorrhages enrolled women in excess of their representation in the underlying population (summary EDD = -0.117 [95% CI = -0.150, -0.084]). Conclusions: Overall, women were modestly under-represented in contemporary acute stroke trials compared to their representation among all strokes. Further study is needed to elucidate factors driving sex differences in enrollment between RCTs.