Macular Edema Trials Underrepresent Patients From Minority Groups

A discrepancy exists between racial and ethnic demographic data in randomized clinical trials (RCTs) of diabetic macular edema (DME) and retinal vein occlusion (RVO) and the US population recorded by the 2010 census, according to a study published in JAMA Ophthalmology. Resolving this discrepancy could improve the external validity of trial findings, according to researchers.

The cross-sectional retrospective analysis compares the distribution of race and ethnicity in RCTs of DME and macular edema from RVO to that of US census data. The researchers analyzed demographic characteristics from RCTs between 2004 and 2020, searching PubMed and clinicaltrials.gov to screen for completed phase 3 RCTs with published results. 

Of 169 trials screened, 23 trials were included (15 DME and 8 macular edema from RVO). Each RCT had recorded the number and percentage of American Indian or Alaska Native, Asian, Black, Hispanic, Native Hawaiian or Other Pacific Islander, and White participants. The researchers compared the demographic distribution and proportion of the RCTs to the reported distribution and proportion in the 2010 US Census using the χ2 test.

The study found that American Indian or Alaska Native and Hawaiian or Other Pacific Islander participants were underrepresented in 2 trials. Asian participants were underrepresented in 10 trials and overrepresented in 4 trials. Black participants were underrepresented in 9 trials and overrepresented in 2 trials, and Hispanic participants were underrepresented in 15 trials and overrepresented in 2 trials. Finally, White participants were underrepresented in 2 trials and overrepresented in 14. There was a significant difference observed in the χ2 values comparing RCT demographic distribution to US Census data in 22 of 23 included RCTs.

The researchers explained that recruitment and representation in RCTs relating to DME and RVO largely fails to reflect the reality of U.S. racial and ethnic demographics, especially as the country’s diversity has increased by a great amount in recent years.

“Although the chance that in the US, 2 individuals chosen at random are 6.2% more likely to be from different racial or ethnic backgrounds in 2020 than in 2010, clinical trials continue to underrepresent minorities and possibly contribute to continued health care disparities,” the study authors explain.

Study limitations include its use of 2010 Census data for analysis of studies conducted between 2004 and 2020, leading to possible confounding of the determination of underrepresentation or overrepresentation of racial and ethnic groups.