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

Abstract

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 US-based glaucoma clinical trials over 2 decades and evaluate disparities in participant representation relative to national demographics and disease prevalence.

Design: A retrospective cross-sectional study.

Subjects: Patients enrolled in US-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 US 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 US census data. Geographic representation was evaluated against regional glaucoma prevalence estimates from the Centers for Disease Control and Prevention Vision and Eye Health Surveillance System. 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 with national census and glaucoma prevalence data.

Results: Among 95 trials, the proportion reporting race/ethnicity increased from 27.08% in decade 1 to 72.34% in decade 2 (OR: 0.14; 95% confidence interval [CI]: 0.06-0.35; P < 0.001). Geographic reporting remained unchanged (58.33% vs. 51.06%; 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), whereas the Midwest had lower enrollment (6.4% vs. 20.4%; P = 0.027), although this was not statistically significant after Bonferroni correction. The South and West were proportionally represented.

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

Financial disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Keywords: Disparities; Glaucoma; Health care access; Health equity; Social determinants of health.