I wrote in the Guardian about the shocking (not) discovery that clinical trials in the UK featured nearly twice as many all-male trials as all-female trials. In response to this finding, the Guardian editorial board wrote, “It is shocking that while illnesses specific to men are studied, those affecting women are ignored“
“The first step, they say, is admitting you have a problem, and on that front the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) has made some much-needed progress. The agency, which is responsible for approving all clinical trials in the UK, has identified a “notable imbalance” in trials conducted between 2019 and 2023: there were nearly twice as many all-male trials as all-female trials.
This imbalance is hardly surprising: as I documented in Invisible Women, my book on the female data gap, the failure to adequately represent women in clinical trials is a longstanding and global problem. The MHRA’s figures are also in line with a recent US analysis that found male-prevalent diseases receive nearly twice as much funding as female-prevalent diseases, both absolutely and relative to disease burden. So far, so disappointingly standard.
Still, it’s not all bad news. When I originally looked into the clinical trial landscape in the UK back in 2018, I was shocked to find that we were something of an outlier when it came to tackling the data gap in women’s health – and not in a good way. Unlike the EU, the US, Canada and Australia, the UK stood out for its failure to say anything at all on the subject. There were no funding requirements, no approval requirements. We didn’t even collect any data to track the problem. In this context (not to mention the backdrop of the Trump administration’s swerve away from evidence-based research), the fact that the MHRA has – for the first time ever – conducted this research is extremely welcome.
The analysis also found that 90% of trials included both sexes, which might on the face of it seem to be more good news . But here’s where it gets more complicated: the inclusion of both sexes in a trial by no means guarantees that researchers will consider any differences between the sexes. An analysis of 10 years of preclinical trials in the US showed that, although there was an increase in the number of studies that included both sexes, there was no proportional increase in analysis and reporting by sex. Meanwhile, across a range of disciplines, only 5-14% of studies examine outcomes by sex, and fewer than a third of the results from phase three trials are reported by sex in medical journals.”