Sex, racial, and ethnic disparities in United States liver transplantation clinical trials.

Background: Regulatory agencies are increasingly recognizing that minority trial representation is inadequate, contributing to healthcare disparities. The scope of minority population disparities in clinical trial participation remains unclear, as previous studies have compiled enrollment data from published trials, which frequently do not report participant race and ethnicity.

Aim: To evaluate sex, racial and ethnic inequities in liver transplantation (LT) trials participation in the United States.

Methods: We used data from completed United States liver transplant clinical trials registered and reported on the National Institute of Health (NIH) website (clincaltrials.gov). Demographic data, including race, ethnicity, sex, and age were collected. To make inferences to a larger population, 95%CIs were computed for estimates in each demographic group using the Wilson method for binomial proportions. We also computed the simultaneous 95%CIs by applying a Bonferroni correction to reflect the multinomial distribution of race proportions. The numbers and percentages of racial/ethnic minority and female individuals compared with United States census data from 2010 and 2018. Secondary outcome measures were inclusion by trial funding source and year of completion.

Results: A total of 69 United States based clinical trials involving 6990 participants were included in the analysis. Of these, 35 trials (51%) were randomized, and 26 (38%) were conducted across multiple United States regions. All trials reported sex, while 42 (61%) reported race and 27 (39%) reported ethnicity. Compared to United States census data, Asian individuals were overrepresented (9.3%; 95%CI: 8.1%-10.5%), whereas African American (7.8%; 95%CI: 6.7%-8.9%) and American Indian or Alaska Native individuals (0.4%; 95%CI: 0.1%-0.6%) were underrepresented. The proportion of White participants (75.9%; 95%CI: 74.1%-77.7%) was consistent with census estimates. Hispanic participants were underrepresented (13.3%; 95%CI: 12.2%-14.5%) regardless of the census year referenced. In industry-sponsored trials, Asian representation was three times higher than in the general population (15%). NIH funded trials showed overrepresentation of White participants (83.8%) and underrepresentation of Black participants (4.1%) relative to census data. Women comprised 31.1% of all participants (95%CI: 30.0%-32.2%), indicating underrepresentation. Among trials that reported racial data, 62 (90%) did not include participants of American Indian or Alaska Native, Native Hawaiian, or Pacific Islander descent.

Conclusion: Our analysis indicates that women, African Americans, and Hispanic individuals are underrepresented in LT clinical trials compared to the general United States population. These results highlight the need for regulatory initiatives aimed at enhancing the inclusion of historically marginalized racial and ethnic groups in clinical research.