Equity Gaps in Sex, Racial, and Ethnic Inclusion in United States Heart Transplant Trials.

BACKGROUND &

OBJECTIVE

Heart transplantation (HT) remains the definitive therapy for select patients with end-stage heart failure. Equitable representation in clinical trials is essential to ensure that evidence guiding HT practice is generalizable across populations. However, the extent of sex, racial, and ethnic inclusion in U.S. HT clinical trials has not been systematically evaluated at the level of clinical trials.

METHODS

We conducted a cross-sectional analysis of U.S.-based HT clinical trials, with publicly available results, registered on ClinicalTrials.gov between 2000 and 2025. Demographic data on sex, race, and ethnicity were independently extracted and categorized using federal reporting standards. Trial enrollment distributions were compared with 2010 and 2020 U.S. Census data and with the overall HT data. Proportions were estimated with Wilson 95% confidence intervals, and racial distributions were assessed using multinomial confidence intervals with Bonferroni adjustment.

RESULTS

Twenty-seven eligible trials encompassing 2,271 participants were included. Female representation was low at 24.2% (95% CI: 22.5%-26.0%), below both U.S. population benchmarks (∼50%) and HT recipient proportions (27.0% in 2010; 28.4% in 2020). White participants were overrepresented (75.3%) compared with 61.6% in the 2020 U.S. population and 59.3% of HT recipients. Black participants comprised 15.5% (95% CI: 12.2%-19.5%), lower than HT populations (25.0% in 2020). Hispanic/Latino (9.7%) and Asian (1.7%) participants were markedly underrepresented relative to national (18.7%and 6.0%, respectively) populations. Multiracial (0.3%) and Indigenous and Pacific Islander participants (0%) were nearly absent. Race and ethnicity reporting improved over time, with universal reporting in trials conducted after 2020.

CONCLUSION

U.S. HT clinical trials demonstrate persistent and clinically meaningful inequities in sex, racial, and ethnic representation. These gaps may compromise the external validity of trial findings and perpetuate disparities in transplant care. Deliberate efforts to standardize demographic reporting, implement equity-focused enrollment strategies, and align trial populations with the evolving demographics of advanced heart failure are urgently needed.