The study highlights the need for increased efforts to promote diversity and inclusivity in ophthalmology clinical trials. Photo: Getty Images.

Efforts have been made over the years to address the disproportionate enrollment of racial and ethnic groups in medical trials so that findings could be more accurately representative of disease rates within specific cohorts, but it’s unclear how effective such efforts have been. In a new study, researchers investigated the representation of different gender, racial and ethnic groups in three ophthalmology clinical trials conducted in the United States between 1997 and 2022 and found that Asian and Hispanic groups were underrepresented, white populations were overrepresented, while Black subjects were found to be comparable to US population estimates.

Of the total clinical trials included in the study, less than half (43.6%) provided information about the racial or ethnic backgrounds of their participants. The majority of the enrollees in trials were female (median 57.5%). White populations were overrepresented and minorities, including Asian, Hispanic and ‘other’ categories, were underrepresented compared to the 2010 US Census. The enrollment of Black individuals, however, was found to be comparable to the US population estimates.

“Our findings suggest that the phase of study, the primary condition and number of participants are associated with rate of reporting, with higher reporting observed in earlier phases of studies and trials with larger participants,” the authors explained in their article for Ophthalmology Science. “Lower reporting rates were observed in cornea trials and in studies with a smaller number of participants.” This is consistent with earlier research on US clinical trials, which have confirmed higher reporting rates in Phases I through III trials compared to Phase IV ones, they continued. “The higher reporting rates in the initial phases are likely due to the heightened surveillance and oversight of these trials as success.”

The trials analyzed also had a higher enrollment of female subjects compared to the Census data, and the numbers have increased over time; this can be attributed to the impact of biological sex on the prevalence of certain ophthalmic conditions such as autoimmune disease, uveitis and dry eye, or the higher usage of preventive services and public healthcare by women, previous studies show, the researchers note.

The authors found it interesting that the enrollment of Black individuals was comparable to the US population estimates. They explained that it could be due to increased awareness among study teams and the implementation of targeted strategies to improve access to advanced healthcare services for Black citizens, but further research is necessary to determine and compare the prevalence rates of various eye disorders among Black individuals to their enrollment rates in trials.

“For example, conditions like glaucoma and diabetic retinopathy are known to be more prevalent among this population. This aligns with our data, which showed a higher recruitment of Black individuals in glaucoma studies,” the authors wrote. “On the other hand, studies have shown a higher prevalence and severity of dry eye disease among Asian populations, yet they were notably underrepresented in cornea trials. Lower participation of minorities may also reflect structural distrust of these groups towards the healthcare system, cultural and linguistic barriers and difficulties accessing healthcare services.”

For individuals living in remote areas or those with limited financial resources, this hinders their participation in trials. Bridging the accessibility gap is possible by establishing local centers with healthcare professionals from the same communities, the authors suggested.

In addition to the low trial enrollment rates of Asian and Hispanic subjects, their representation did not improve substantially over time. “As the population becomes more diverse, underrepresentation of minorities in research will become an increasingly pressing issue, raising concerns about safety, efficacy and generalizability of medical interventions,” the authors explained. “A holistic approach is needed to diversify clinical trial participants to reflect the changing racial/ethnic composition of target populations.

“Ensuring equitable inclusion of different gender, racial and ethnic groups in these trials is essential for minimizing disparities and producing unbiased scientific findings generalizable to the entire population,” the authors concluded.

Montazeri F, Wang M, Atkuru A, et al. Racial/ethnic and gender diversity in the United States ophthalmology clinical trials. Ophthalmol Sci. September 11, 2023. [Epub ahead of print,]