Racial and Ethnic Distribution in Diabetic Macular Edema Clinical Trials in the United States (2002-2021)

Diabetic macular edema (DME), the leading cause of vision loss among patients with diabetes mellitus, disproportionately affects Black and Hispanic patients. Currently, non-White racial and ethnic subgroups are frequently underrepresented in clinical trials, limiting the application of results to the most pertinent patient populations. Thus, we aimed to characterize the trajectory of racial reporting as well as changes and disparities in racial and ethnic distribution among participants of DME clinical trials.

This is a cross-sectional retrospective study.

Patients enrolled in United States (US)-based clinical trials for DME.

We examined the racial and ethnic demographic distribution of participants in clinical trials related to DME across a 20-year period from 2002 to 2021. Clinical trials were screened from ClinicalTrials.gov for DME, US trial location, study completion, and > 50 patient enrollment. Descriptive statistics, proportions, odds ratios (ORs), and chi-square tests were reported and compared with 2021 US Census demographic data and diagnosed patients with diabetes demographic data.

Change in racial reporting and race/ethnicity across 2 decades and comparison of racial/ethnic distribution with 2021 US Census demographics and diagnosed patients with diabetes.

There was an increase in race reporting from January 2002 to December 2011 (8 trials [40%]) versus January 2012 to December 2021 (20 trials [87%]; OR, 10.00; 95% confidence interval [CI], 2.21-45.16; P = 0.0032). Across the 2 decades, the proportion of Asian patients enrolled increased from 2.4% to 8.0% (OR, 3.47; 95% CI, 2.64-4.56; P < 0.0001). Similarly, the proportion of enrolled Hispanic patients increased from 13.4% to 19.5% (OR, 1.56; 95% CI, 1.37-1.78; P < 0.0001). Compared with diabetes prevalence, many minority groups are underrepresented in the total enrollment of DME clinical trial patients (Black [z = -18.51, P < 0.001]; Asian [z = -5.11, P < 0.0001]; Hispanic [chi-square = 274.7, df = 1, P < 0.0001]).

In the past 2 decades, there has been a trend of increased racial reporting and minority patient enrollment in DME clinical trials. However, Black, Asian, and Hispanic patients remain significantly underrepresented among the DME clinical trial patient population based on diabetes prevalence.

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.