For the new study, investigators analyzed 281 stroke trials that included at least 100 patients each and were conducted between 1990 and 2020.
Of the nearly 590,000 total participants, 37.4% were women. However, the average rate of stroke among women in the countries where the studies were conducted was 48%, according to the report published online Oct. 13 in the journal Neurology.
"Making sure there are enough women in clinical studies to accurately reflect the proportion of women who have strokes may have implications for future treatment recommendations for women affected by this serious condition," said study author Dr. Cheryl Carcel, from the George Institute for Global Health, in Sydney, Australia.
"When one sex is underrepresented in clinical trials, it limits the way you can apply the results to the general public and can possibly limit access to new therapies," Carcel explained in a journal news release.
The overall 0.84 ratio of women in stroke trials did not change over the study period. A ratio of one would mean that the percentage of women in stroke trials matched the percentage of women with stroke in the general population.
The lowest ratios were in: trials of a type of bleeding stroke called intracerebral hemorrhage (0.73); trials in which the average patient was younger than 70 (0.81); trials of non-acute interventions (0.80); and rehabilitation trials (0.77).
"Our findings have implications for how women with stroke may be treated in the future, as women typically have worse functional outcomes after stroke and require more supportive care," Carcel said.
"We will only achieve more equitable representation of women in clinical trials when researchers look at the barriers that are keeping women from enrolling in studies and actively recruit more women," she added. "People who fund the research also need to demand more reliable, sex-balanced evidence."
The researchers noted that because the study included only clinical trials registered on a U.S. government website, it may not have included all stroke trials.
The U.S. Office on Women's Health has more about stroke.
SOURCE: Neurology, news release, Oct. 13, 2021