Progression of Diabetic Retinopathy in Presence of Age-related Macular Degeneration

Abstract

Purpose : To evaluate the association between the presence of age-related macular degeneration (AMD) and progression of diabetic retinopathy (DR).

Methods : We retrospectively identified patients with at least mild nonproliferative diabetic retinopathy (NPDR), with or without AMD at the Joslin Diabetes Center. Inclusion criteria were age >50yrs, baseline visit between 2007-2014, >3 years of follow-up, and ICD-9/10 diagnosis code of mild to severe nonproliferative diabetic retinopathy (NPDR) with or without AMD. Patients were excluded if they had received prior anti-vascular endothelial growth factor (VEGF) injections or had proliferative DR (PDR) or neovascular AMD at baseline. AMD grading used the Age-Related Eye Disease Study classification system. DR progression was defined as >2-step progression in clinical grade or progression to PDR. Multivariable Cox regression analysis and Cox proportional hazards regression model were used to assess factors associated with progression of DR. Mediation analysis was performed in patients who had both baseline hemoglobin A1c (HbA1c) and average HbA1c values to investigate whether average HbA1c mediates the association between the presence of AMD and progression of DR.

Results : After exclusion, there were 223 eyes (138 patients) with DR with AMD and 476 eyes (260 patients) with DR without AMD included in the analysis. A total of 61 eyes (9.87%) had either ≥2-step progression of DR or progression to PDR during the follow up period (50 eyes (7.5%) had ≥2-step progression of DR and 46 eyes (6.6%) progressed to PDR). The rates of ≥ 2-step DR progression (HR 0.34, 95% CI 0.12~0.97, p=0.044) and progression to PDR (HR 0.34, 95% CI 0.13~0.90, p=0.0304) were lower in eyes with AMD compared to eyes without AMD in multivariable Cox regression analysis. Mediation analysis revealed that the association between the presence of AMD and decreased progression of DR was not affected by diabetic control measured by average HbA1c. Subgroup analysis revealed that there is a possible protective effect against ≥2-step DR progression and/or progression to PDR with lower HbA1c at baseline and current smoking status.

Conclusions : There is a lower rate of DR progression in patients with mild to severe NPDR when AMD coexists at baseline compared to those without AMD. The presence of AMD may have a protective effect against DR progression independent of diabetic control measured by HbA1c.

This is a 2021 ARVO Annual Meeting abstract.