Characteristics of Ophthalmology Trials Registered in ClinicalTrials.gov, 2007-2018

Abstract

To perform a comprehensive analysis of characteristics of ophthalmology trials registered in ClinicalTrials.gov. Cross-sectional study. All 4,203 ophthalmologic clinical trials registered on ClinicalTrials.gov between October 1, 2007, and April 30, 2018, were identified by using medical subject headings (MeSH). Disease condition terms were verified by manual review. Trial characteristics were assessed through frequency calculations. Hazard ratios and 95% confidence intervals were determined for characteristics associated with early discontinuation. The majority of trials were multiarmed (73.6%), single-site (69.4%), randomized (64.8%), and had <100 enrollees (66.3%). A total of 33% used a data-monitoring committee (DMC), and 50.6% incorporated blinding. Other groups (51.6%) were funded by industry, whereas 2.6% were funded by the US National Institutes of Health (NIH). NIH trials were significantly more likely to address oncologic (NIH= 15.5%, Other= 3%, Industry= 1.5%; P < 0.001) or pediatric disease (NIH= 20.9%, Other= 5.9%, Industry= 1.4%; P < 0.001). Industry-sponsored trials (69.6% of phase 3 trials) were significantly more likely to be randomized (Industry= 68.7%, NIH= 58.9%, Other= 60.8%; P < 0.001) and blinded (Industry= 57.2%, NIH= 42.7%, Other= 43.5%; P < 0.001). A total of 359 trials (8.5%) were discontinued early, and 530 trials (12.6%) had unknown status. Trials were less likely to be discontinued if funded by sources other than industry (hazard ratio [HR], 0.72; 95% confidence interval [CI], 0.55-0.95; P= 0.021) and/or had a DMC (HR, 0.71; 95% CI, 0.55-0.92; P= 0.010). Ophthalmology trials in the past decade reveal heterogeneity across study funding sources. NIH trials were more likely to support historically underfunded subspecialties, whereas Industry trials were more likely to face early discontinuation. These trends emphasize the importance of carefully monitored and methodologically sound trials with deliberate funding allocation.