Women have been under-represented in stroke clinical trials for the past 30 years, new research has found, making it harder to interpret what the findings really mean for them.
The study found that more than three quarters of the trials enrolled less women than the expected proportion that experience stroke in the community.
George Institute researchers looked at 281 stroke trials that had at least 100 participants and were conducted between 1990 and 2020.
The total number of participants was 588,887, of whom 37.4 per cent were women, but the average prevalence of stroke in women across the countries included was 48 per cent.
“It’s now time to put policy into practice so that future research can address our knowledge gaps in the understanding and treatment of stroke in women,” said study co-author Dr Katie Harris.
While there have been studies showing varying degrees of representation of women in cardiovascular trials, this issue has only recently started to be examined in relation to stroke trials.
The greatest differences were seen in trials involving a particular type of stroke known as intracerebral haemorrhage, those where the mean age of participants was less than 70.
Lead author Dr Cheryl Carcel, from The George Institute for Global Health and a Heart Foundation Fellow, said that while both women and men had the same one-in-four risk of experiencing a stroke in their lifetime, women were much older and in worse health at the time they have a stroke.
“These 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,” said Dr Carcel.
Dr Carcel said the reasons for this under-representation were complex and most likely due to a number of factors, including recruitment criteria that unintentionally exclude women like age and having other health conditions.
“Patient attitudes and beliefs can also be a factor, and there can even be a potential bias among the clinical staff conducting the study,” she said.
“Our previous research indicated that how women were treated in hospital and whether they had been on the right medications before their stroke, could be responsible for their poorer outcomes.”
Dr Harris said that barriers and facilitators to women’s participation in stroke trials needed to be explored both at the trial and patient level to help redress the balance.
“Achieving a better gender representation in stroke trials can provide a more reliable assessment of the treatment benefits and harms, and inform treatment guideline recommendations for women affected by this serious condition,” she said.
While the United States, Canada and some European countries, adopted policies to boost the number of women in clinical trials over the course of the study, the results showed no change over this time.
“Our study suggests those efforts have clearly not translated into action,” Dr Harris added.
