Enrolment characteristics in age-related macular degeneration clinical trials: a cross-sectional study

To investigate demographic enrolment characteristics in age-related macular degeneration (AMD) trials.

Clinicaltrials.gov was searched with "age-related macular degeneration" to identify RCTs with double, triple, or quadruple masking. Trial (e.g., study location, phase, masking, trial initiation year, and sponsor origin) and patient demographic data were collected. Sex-based AMD disease burdens were retrieved from the Global Burden of Disease database to calculate pooled female population-to-prevalence ratios (PPRs). Equitable trial enrolment was defined as PPR between 0.8-1.2. Demographic proportions were evaluated across trial characteristics using the Kruskal-Wallis test (alpha = 0.05) followed by post hoc comparisons. Secondary outcomes included absolute number of enrolled female, racial, and ethnic groups, and the association of trial characteristics with these demographics.

We included 106 trials (77,939 patients; 46.3% female), spanning 1990-2020. The pooled female PRR was 0.88 (95% confidence interval [CI]: 0.82, 0.94). PPR values were inconclusive studies with quadruple blinding; phase I, III, IV, or not applicable status; foreign (non-US) site; US-only and foreign-only sponsor; and an initiation year before 2010. There was no significant difference in PPR between sublevels of analysed trial characteristics. Of the 74 (69.8%) trials that adequately detailed race, White participants comprised the largest group (N = 57,917; 82% of total participants). Thirty-seven (34.9%) trials adequately detailed ethnicity. The absolute enrolment of race and ethnic groups did not generally exhibit significant difference between sublevels of analysed trial characteristics.

Female enrolment was commensurate to their disease burden across all trial characteristics. Race and ethnicity were under-reported. Future trials should prioritise equitable study enrolment strategies.