Representation of women in stroke clinical trials: a review of 281 trials involving over 500,000 participants

Objective: Women have been under-represented in clinical trials areas of
cardiovascular disease but there is less certainty over the level of
disparity specifically in stroke. We examined the participation of women
in trials according to stroke prevalence in the population. Methods:
Published randomized controlled trials with ≥100 participants enrolled
between 1990 and 2020 were identified from ClinicalTrials.gov. To quantify
sex disparites in enrolment we calculated the participation to prevalence
ratio (PPR), defined as the percentage of women participating in a trial
against the prevalence of women in the disease population. Results: There
were 281 stroke trials eligible for analyses with a total of 588,887
participants, of whom 37.4 % were women. Overall, women were represented
at a lower proportion relative to their prevalence in the underlying
population (mean PPR 0.84; 95% confidence interval [CI] (0.81 to 0.87)).
The greatest differences were observed in trials of intracerebral
hemorrhage (PPR 0.73; 95% CI 0.71 to 0.74), trials with a mean
age of participants <70 years (PPR 0.81; 95% CI (0.78 to 0.84)),
non-acute interventions (PPR 0.80; 95% CI (0.76 to 0.84)) and
rehabilitation trials (PPR 0.77; 95% CI 0.71 to 0.83)). These findings did
not significantly change over the period from 1990 to 2020 (p for trend =
0.201). Conclusion: Women are disproportionately represented in stroke
trials relative to the burden of disease in the population. Clear guidance
and effective implementation strategies are required to improve the
inclusion of women and thus broader knowledge of the impact of
interventions in clinical trials.