Based on available clinical trial data, black patients show less improvement in visual acuity than white patients when treated with ranibizumab for diabetic macular edema.
The racial difference disappears when the statistics are adjusted for factors such as HbA1c levels. However, the results raise questions that highlight the lack of ethnicity data in clinical trials of retinal treatments, said M. Ali Khan, MD, assistant professor of ophthalmology at Thomas Jefferson University in Philadelphia.
“The ultimate message of the project is that we need to do better at recruiting patients from different backgrounds,” he told Medscape Medical News.
Khan presented his findings at the American Society of Retina Specialists (ASRS) annual meeting in 2021.
Few researchers have reported racial or ethnic differences in response to treatments for retinal disease. “And I think that with the George Floyd protests, people were obviously a little more interested in making sure we got things right about diversity and inclusion,” said Khan.
Khan and his colleagues therefore examined data from Protocols I, S, and T of the Diabetic Retinopathy Clinical Research Network (DRCR) and the Genentech-funded RISE and RIDE studies of ranibizumab.
They counted a total of 928 white and 181 black patients in the five studies. They found that white patients started with an observed mean best corrected visual acuity (BCVA) of 62.0 ETDRS letters, which increased to 72.2 at 24 months, an improvement from baseline of 10.0 letters. Black patients started with a mean of 66.7 letters that rose to 72.8, an improvement of 7.8 letters. The difference in the improvement letters was statistically significant (P = .04).
At the same time, 27.6% of the black patients and 35.0% of the white patients had an increase of at least 15 letters, which was just below statistical significance (P = .05).
The differences between the two races resulted from the RISE and RIDE data; Differences in the other studies were not statistically different.
And those differences disappeared when the researchers matched the black patients with white patients of similar age, gender, HbA1c, central subfield, and BCVA at baseline and a similar number of ranibizumab injections and visits at 24 months.
The same was true when the patients were matched for all of these characteristics except HbA1c and also when only the baseline characteristics were considered.
The researchers would have liked to include more factors such as kidney function and socio-economics in their analysis, but limited themselves to what was collected in these studies, Khan said.
Likewise, they were unable to analyze differences between Asian, Latin American, and other ethnic and racial groups because these studies did not include enough patients from these groups.
It might be useful to divide up some of these races and ethnic groups, for example by distinguishing between people with ancestors from different parts of Asia or Latin America, he said.
Under-representation of colored people is common in other medical specialties, Khan said. “It just means we need to better enroll these patients in clinical trials, and how to do that is the harder question,” he said.
Hiring more principal color researchers could help, he said, adding that researchers should work to break down any language barriers.
Research in other medical specialties has identified socioeconomic factors and distrust of medical professionals as factors limiting recruitment of underrepresented groups, Abdul-Hadi Kaakour, MD, MS, a fellow at the Cleveland Clinic, said in an email.
In a related study presented by Kaakour at ASRS, he and his colleagues compared the representation of ethnic and racial groups in 15 randomized controlled trials of diabetic macular edema. You have found that:
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the white patient cohort was underrepresented in two and overrepresented in 10
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the black patient cohort was underrepresented in six and overrepresented in three
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the Hispanic patient cohort was underrepresented in nine and overrepresented in three
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the Asian patient cohort was underrepresented in eight and overrepresented in three
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the Indian / Alaskan and Hawaiian / Pacific Islander patient cohort was underrepresented in four cases.
“Each person’s barriers will also be unique. Therefore, it will at least allow the clinician to spend additional time with patients who identify as underrepresented minorities, understand their particular barriers, and find constructive ways to overcome them, ”Kaakour told Medscape Medical News.
Neither Kaakour nor Khan reported any relevant financial interests. The study presented by Khan was funded by Genentech.
American Society of Retina Specialists (ASRS) annual meeting 2021. Presented on October 9, 2021.
Laird Harrison writes about science, health and culture. His work has appeared in national magazines, newspapers, public radio and websites. He is working on a novel about alternative realities in physics. Harrison teaches writing at the Writers Grotto. Visit him at lairdharrison.com and follow him on Twitter: @LairdH
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