Inequalities in enrollment of women and racial minorities in trials testing uric acid lowering drugs

We investigated sex and racial inequalities in clinical trials testing serum uric acid (SUA) lowering drugs and analyzed the temporal trends of participation among the pre-specified demographic groups. Data were collected from publications of clinical trials testing SUA-lowering drugs. Linear regression analysis was performed to assess the relation between drug approval year and proportion of women and minorities enrolled in clinical studies.The mean percentage enrollment of women in clinical trials significantly decreased over the time (r = -0.43, P-value = 0.02). Moreover, there was a statistically significant difference in mean percentage enrollment of women among trials testing different SUA-lowering drugs, with the highest representation in rasburicase (71.1%) and the lowest representation of women in dotinurad (0.8%). Over the time, also the mean percentage enrollment of racial minorities decreased, passing from 8.7% to 2.2% in a 10-year period. Women were proportionally underrepresented compared with their share of the population with asymptomatic hyperuricemia, overall (participation-to-prevalence ratio (PPR) = 0.34), in trials testing xanthine oxiase inhibitors (PPR = 0.38) and uricosurics (PPR = 0.29), and in trials with febuxostat, allopurinol, pegloticase, halofenate/arhalofenate, verinurad, lesinurad and dotinurad. Women were proportionally underreppresented also compared with their share of the population with gout, overall (PPR = 0.69) and in trials testing XOIs (PPR = 0.69), uricosurics (PPR = 0.68), and all SUA-lowering drugs excepted for rasburicase, pegloticase and topiroxostat.Our analysis shows that women and racial and ethnical minorities are underrepresented in controlled clinical trials testing SUA-lowering drugs, with similar pattern across drug classes.