In a meta-analysis of five randomized clinical trials, researchers investigated whether race influenced visual outcomes in patients with diabetic macular edema who were treated with ranibizumab.

In the study, published in JAMA Ophthalmology, the researchers compared long-term best-corrected visual acuity (BCVA) results between Black and White participants and found no statistically significant differences in outcomes at 24 months after adjusting for baseline variables.

Lead study author M. Ali Khan, MD, of the Wills Eye Hospital in Philadelphia, and colleagues included data from five landmark trials in their analysis: RIDE, RISE, DRCR.net Protocol I, Protocol S, and Protocol T. A total of 1,109 participants who received ranibizumab (0.3 mg or 0.5 mg) and had both baseline and 24-month BCVA data were included. Most of the participants were White (n = 928), whereas the other 181 participants were Black. Participants who identified as other races (n = 99) were excluded because of the small sample size.

The participants’ mean ages were 57.9 years (Black participants) and 60.4 years (White participants). At baseline, mean HbA1c was higher in Black participants (8.4%) vs White participants (7.9%, P < .001), but BCVA was greater in Black participants compared with White participants (mean Early Treatment Diabetic Retinopathy Study [ETDRS] score = 66.7 vs 62, respectively; P = .01). Almost half (47.5%) of Black participants had 20/40 or better vision at baseline vs 30% of White participants.

At the 24-month primary endpoint, the mean BCVA was similar between the groups (Black = 72.8, White = 72.2). Black participants gained a mean of 6.1 ETDRS letters (unadjusted; + 7.7 adjusted) compared with White participants who gained a mean of 10.2 ETDRS letters (unadjusted; + 9.9 adjusted). A higher number of White participants also gained more than 15 letters compared with Black participants (35% vs 27.6%, respectively; P = .05), though the number of participants who lost at least 15 letters was similar between the groups.  

To account for baseline and on-study differences, a propensity score–matched subgroup was created using RIDE and RISE trial data:

• Matched participants: 39 Black and 39 White
• Mean BCVA gain: Black: + 10.6 letters, White: + 10.1 letters (P = .83)
• Sensitivity analyses that removed HbA1c or visit frequency from models yielded similar results.

In subgroup analyses of participants with worse than 20/50 vision at baseline, the researchers found no statistically significant difference in 24-month BCVA gains: Black participants in this group gained 11.8 letters, whereas White participants gained 15 letters (P = .07). Among participants with at least 20/40 vision at month 24, the researchers found that vision gains were lower in Black vs White participants (10.9 vs 13.8 letters, P < .001), and fewer Black participants achieved a 15-letter gain or more (30.6% vs 42.5%, P = .01).

The researchers acknowledged limitations, including the small numbers of non-Black and non-White participants that precluded analysis of other racial or ethnic subgroups, as well as the relative sample size of Black vs White participants. The study was also limited to ranibizumab-treated arms only, and only BCVA at 24 months was analyzed; anatomical outcomes and other clinical endpoints were not included.

“The prevalence of diabetic retinopathy and diabetic macular edema (DME) are higher in Black and Hispanic participants in the [United States], and the likelihood of developing DME may be higher in Black participants. Furthermore, the risk of sustained blindness may be higher in Black and Asian than White participants,” the study authors wrote. “These findings suggest that more robust data are required to determine the impact of race on DME outcomes in response to ranibizumab therapy,” they added.

Steps such as increased enrollment of underrepresented racial subgroups in future clinical trials and greater characterization of race and ethnicity beyond traditional categories, along with information on social determinants of health “will better allow for comprehensive evaluation of the effects of race on treatment outcomes,” the study authors concluded.

Disclosures can be found in the published study.