Gender Disparities in Nephrology Trials: A Meta-Analysis of Enrollment Trends between 2000 and 2021

KEY POINTS: Women are under-represented in high-impact nephrology trials. Trends remain consistent over the past 20 years and on the basis of target condition. Addressing the imbalanced enrollment of women in trials could improve disparities in care and outcomes of kidney disease. BACKGROUND: Gender disparities in the incidence and complications of kidney diseases are well described. However, analysis to elucidate gender disparities in enrollment in nephrology randomized clinical trials (RCTs) has not been performed. METHODS: We performed a systematic review and meta-analysis of high-impact nephrology RCTs published between 2000 and 2021. We included RCTs enrolling participants aged 18 years and older in the following categories: (1) CKD, (2) AKI, (3) GN, (4) maintenance dialysis, and (5) kidney transplantation. We summarized trial characteristics according to reporting and enrollment of participants, enrollment site, publication year, trial category, and intervention type. Outcomes of interest include the proportion of enrolled male and female participants overall and according to trial category. In addition, we compared enrollment trends in the United States and globally to estimates of kidney disease prevalence. RESULTS: Most qualifying trials (373/380, 98%) reported the distribution of male and female participants. Enrollment was imbalanced overall with male participants accounting for 62% (n=215,850) of the enrolled participants and female participants for just 38% (n=133,082). Male participants formed most of trial cohorts in AKI (65%), CKD (62%), dialysis (55%), and transplant trials (65%), whereas women were majority enrollees in GN trials (61%). CKD trials under-represented women in both US trials and worldwide. CONCLUSIONS: Women are under-represented in high-impact nephrology trials with the exception of GN trials. This imbalance may contribute to disparities in outcomes and gaps in the care of women with kidney disease.