Representation of Race and Ethnicity in Randomized Clinical Trials of Diabetic Macular Edema and Retinal Vein Occlusion Compared to 2010 US Census Data
Authors: Kaakour Abdul-Hadi , Hua Hong-Uyen , Rachitskaya Aleksandra 
Published: October 2022

Importance

Diverse enrollment and adequate representation of racial and ethnic minority groups in randomized clinical trials (RCTs) are valuable to ensure external validity and applicability of results.

Objective

To compare the distribution of race and ethnicity in RCTs of diabetic macular edema (DME) and macular edema from retinal vein occlusion (RVO) to that of US Census data.

Design, Setting, and Participants

This was a cross-sectional retrospective analysis comparing racial and ethnic demographic characteristics of US-based RCTs of DME and RVO between 2004 and 2020 with 2010 US Census data. PubMed and ClinicalTrials.gov were searched to screen for completed phase 3 RCTs with published results. Of 169 trials screened, 146 were excluded because they were incomplete, did not report race and ethnicity, or were not based in the US, and 23 trials were included (15 DME and 8 RVO). The number and percentage of American Indian or Alaska Native, Asian, Black, Hispanic, Native Hawaiian or Other Pacific Islander, and White participants was recorded in each RCT. The demographic distribution and proportion was compared to the reported distribution and proportion in the 2010 US Census using the χ2 test.

Main Outcomes and Measures

Overrepresentation, underrepresentation, or representation commensurate with 2010 US Census data in the racial and ethnic populations of RCTs of retinal vascular disease.

Results

In 23 included RCTs of DME and RVO, there were a total of 38 participants (0.4%) who identified as American Indian or Alaska Native and Native Hawaiian or Other Pacific Islander (groups combined owing to small numbers), 415 Asian participants (4.4%), 904 Black participants (9.6%), 954 Hispanic participants (10.1%), and 7613 White participants (80.4%). By comparison, the 2010 US Census data indicated that 1.1% of the US population self-reported as American Indian or Alaska Native and Native Hawaiian or Other Pacific Islander (groups combined for comparison in this study), 4.8% self-reported as Asian, 12.6% as Black or African American, 16.3% as Hispanic, and 63.7% as White. American Indian or Alaska Native and Hawaiian or Other Pacific Islander participants were underrepresented in 2 trials, neither overrepresented nor underrepresented in 20, and not overrepresented in any of the included trials. Asian participants were underrepresented in 10 trials, overrepresented in 4, and neither overrepresented nor underrepresented in 8. Black participants were underrepresented in 9 trials, overrepresented in 2, and neither overrepresented nor underrepresented in 11. Hispanic participants were underrepresented in 15 trials, overrepresented in 2, and neither overrepresented nor underrepresented in 5. White participants were underrepresented in 2 trials, overrepresented in 14, and neither overrepresented nor underrepresented in 7. The χ2 values comparing RCT demographic distribution to US 2010 Census data were significantly different in 22 of 23 included RCTs.

Conclusions and Relevance

The findings in this study indicated a discrepancy between racial and ethnic demographic data in RCTs of DME and RVO and the US population according to the 2010 Census. White study participants were most frequently overrepresented, and Hispanic study participants were most frequently underrepresented. These findings support the need for more efforts to recruit underrepresented racial and ethnic minorities to improve external validity in trial findings.