Hispanic Ethnicity and OCT-based Biomarkers as Predictive Factors of DME Refractory to Bevacizumab.

Background and objective: While anti-vascular endothelial growth factor (anti-VEGF) therapy has revolutionized treatment for diabetic macular edema, many patients still manifest refractory disease. This study evaluated rates of diabetic macular edema (DME) refractory to intravitreal bevacizumab in a diverse real-world setting, with the aim of studying demographic and optical coherence tomography (OCT)-based morphological factors associated with refractory disease.

Patients and methods: This was a retrospective cohort study of patients receiving treatment. Refractory DME was defined as a gain in visual acuity of < 5 letters after three consecutive injections of bevacizumab or less than 20% reduction in central retinal thickness (CRT) after three consecutive injections of bevacizumab. OCT images from preand post-injection visits were reviewed by two independent image readers. Multivariate logistic regression analysis evaluated for statistical significance between responders and those refractory to bevacizumab, and between Hispanic and non-Hispanic groups.

Results: Ninety-nine patients were included. Of the participants, 42% were Hispanic, 10% were reported as white, 11% were Asian, 11% were Black, and 26% were defined as "not reported." Fifty-four (54.5%) patients were refractory to bevacizumab and 45 were responders. Between responders and refractory patients, race was statistically significant (P = 0.04) with more refractory subjects found to be Hispanic (28/54, 51.9%). OCT morphologic characteristics (CRT, number of hyperreflective foci, disorganization of inner retinal layers, ellipsoid zone discontinuity, and sub-retinal fluid) were not statistically significant between responders and refractory subjects. Multivariate logistic regression demonstrated an odds ratio of 5.7 for refractory disease for Hispanics (CI 1.687 to 19.445, P = 0.01). When comparing Hispanics to non-Hispanics, Hispanics had an average lower baseline visual acuity, lower CSTs, and higher HbA1C.

Conclusions: Our study showed that Hispanics have a nearly 6 times relatively higher likelihood of refractory disease. There is a notable under-representation of these patients in completed clinical trials for diabetic retinopathy and DME. [Ophthalmic Surg Lasers Imaging Retina 2025;56:XX-XX.].