Sex and Gender in Randomized Clinical Trials of Adults Receiving Maintenance Dialysis

It is important to account for sex and gender in randomized clinical trials (RCTs), as these factors can directly impact how individuals experience health conditions and respond to treatment. Sex is defined by biological characteristics, such as hormones, gene expression, and anatomy, whereas gender is a construct based on the social, environmental, cultural, and behavioral factors that influence personal identity, and can exist on a spectrum.

At present, it is largely unknown how sex and gender concepts are incorporated into RCTs of adults with kidney failure who receive maintenance dialysis. In a recent publication in The American Journal of Kidney Disease, Dr. David Collister (CVC Associate Faculty Member) and fellow co-authors examined published articles from high-impact journals between 2000-2020 in order to better understand how sex and gender concepts are incorporated in these studies, and to determine the percentage of women and female participants.

The researchers identified a total of 561 RCTs from high-impact general medicine, nephrology, and cardiology journals, and determined that approximately 40% of participants were female or women. Although the maintenance dialysis RCTs from this study appear to have a more representative proportion of female or women participants, particularly when compared with other disciplines, they found that sex and gender were poorly distinguished, reported inconsistently and/or incompletely, and typically not factored into either the study design or analysis stage.

“This study is important because it showed that females/women are appropriately represented in dialysis RCTs, unlike many other chronic diseases, but the reason for why this is remains unknown. However, we still have a lot of work to do as a nephrology community to properly distinguish between sex and gender in clinical trials starting with adequate reporting and nomenclature,” says Dr. David Collister. “Our research team is looking forward to completing similar meta-epidemiologic work in chronic kidney disease and acute kidney injury clinical trials.”