Adjusting for Glycemic Control in Assessing the Relationship Between Age-Related Macular Degeneration and Diabetic Retinopathy.

Purpose Studies regarding the relationship between age-related macular degeneration (AMD) and diabetic retinopathy (DR) conflict: while some support that AMD is protective against DR, others find the opposite. The mechanism by which AMD may protect against DR is unclear. We sought to assess the association between AMD and DR when controlling for glycemic control in patients with diabetes mellitus (DM) type II. Methods We identified 461 unique patients over 55 years old with a diagnosis of DM type II seen in our academic retina clinic in Stony Brook, New York between 12/31/2019 and 12/31/2020. Data were manually extracted and the population was split based on the presence of AMD diagnosis. Multivariate regression analyses were then performed comparing the prevalence of DR between groups while controlling for A1c. Secondary endpoints included demographic differences and smoking status.  Results Among the 461 patients, 118 (25.6%) had a diagnosis of AMD. Compared to patients without AMD, patients with AMD were older (69 vs. 66; OR 1.05; p=0.005) and less likely to have DR (37.3% vs. 59.2%; OR 0.35; p<0.001). There was no difference in average A1c between groups. Conclusion This is the first reported study assessing the relationship between AMD and DR while controlling for A1c. In our population, diagnosis of AMD was associated with significantly reduced odds of having DR. As AMD and DR appear to be related even after holding A1c constant, researchers should use caution when using DR as a surrogate for diabetic control in the context of AMD.