Racial and Sex Disparities in US Kidney Transplant Clinical Trials: A Comparative Analysis With National Transplant Registry Data.

Introduction: Chronic kidney disease and kidney failure disproportionately affect racial and ethnic minorities in the United States, yet these populations remain underrepresented in clinical trials, especially in kidney transplantation research. The objective of this study was to analyze the representation of racial, ethnic, and sex groups in US-based kidney transplant clinical trials and assess whether participant demographics reflect the population receiving transplants, using national registry data.

Methods: A total of 188 completed interventional trials related to kidney transplantation (1995-2022) were extracted from clinicaltrials.gov. Demographic data-including race, ethnicity, and sex-were compared against national data from the Organ Procurement and Transplantation Network. Chi-square tests and logistic regressions were performed to assess representation trends and predictors of demographic data reporting.

Results: Only 58.51% of trials reported race or ethnicity (P < 0.01). White participants were consistently overrepresented across all time periods, while Black, Asian, multiracial, and Indigenous participants were underrepresented, despite elevated disease burdens (P < 0.0001). From 2011 to 2015 to 2016-2020, Black representation increased significantly (P < 0.001), though still fell short of parity. Multiracial and Asian participants remain markedly underrepresented. Trials with pharmaceutical sponsorship were significantly less likely to report racial or ethnic data (P = 0.008). Females were also underrepresented, comprising only 35.88% of trial participants (P < 0.0001).

Conclusions: The persistent underrepresentation of minority groups and females in kidney transplant trials undermines the generalizability of findings and perpetuates inequities in care. Comprehensive and intersectional demographic reporting should be mandated, and recruitment strategies must prioritize inclusivity to ensure that clinical research equitably serves all affected populations.