Ethnoracial and Geographic Representation in United States Glaucoma Clinical Trials (2004-2023)

Abstract

Ethics statement: The Albert Einstein College of Medicine Institutional Review Board deemed this study to be exempt from formal review because it used only publicly available, de-identified data from ClinicalTrials.gov. The requirement for informed consent was waived and not applicable, as no patient level data was collected or analyzed. All analyses were conducted in accordance with the Declaration of Helsinki and STROBE guidelines.

Purpose: Glaucoma disproportionately affects racial and ethnic minority populations and individuals in medically underserved regions. However, clinical trial data may not reflect this epidemiologic burden. We aimed to characterize trends in race/ethnicity and geographic reporting in U.S.-based glaucoma clinical trials over two decades and to evaluate disparities in participant representation relative to national demographics and disease prevalence.

Design: Retrospective cross-sectional study.

Subjects: Patients enrolled in U.S.-based Phase II-IV clinical trials for glaucoma conducted between 2004 and 2023.

Methods: Trials were identified from ClinicalTrials.gov using all glaucoma-related keywords and filtered for U.S. location, completion status, and ≥50 enrolled participants. Trials were stratified by enrollment period: Decade 1 (2004-2013) and Decade 2 (2014-2023). Demographic distributions were compared with 2010 and 2020 U.S. Census data. Geographic representation was evaluated against regional glaucoma prevalence estimates from the CDC Vision and Eye Health Surveillance System (VEHSS). Descriptive statistics, odds ratios (ORs), and multinomial chi-square tests were used to assess trends in reporting and representation.

Main outcome measures: Change in reporting of race/ethnicity and geography over time; participant race/ethnicity and trial location distribution compared to national Census and glaucoma prevalence data.

Results: Among 95 trials, the proportion reporting race/ethnicity increased from 27.1% in Decade 1 to 72.3% in Decade 2 (OR: 0.14; 95% CI: 0.06-0.35; p < 0.001). Geographic reporting remained unchanged (58.3% vs. 51.1%; OR: 1.34; 95% CI: 0.60-3.02; p = 0.539). Across 13,744 participants in 47 trials reporting race/ethnicity, Black patients were overrepresented in both decades (p < 0.001). Hispanic and Asian participants were persistently underrepresented (p < 0.001). In 52 trials with 14,997 participants, the Northeast was overrepresented (36.2% of trials vs. 18.1% of disease burden; p = 0.002), while the Midwest had lower enrollment (6.4% vs. 20.4%; p = 0.03), though this was not statistically significant after Bonferroni correction. The South and West were proportionally represented.

Conclusions: Although racial/ethnic reporting has improved, U.S.-based glaucoma trials continue to underrepresent Hispanic, Asian, and Midwestern populations. These disparities may limit the generalizability of trial findings and access to emerging therapies for high-risk groups.

Keywords: Glaucoma; disparities; health equity; healthcare access; social determinants of health.