Impact of age-related macular degeneration on diabetic retinopathy: An electronic health record based big data analysis from a tertiary eye centre in South India

PURPOSE: To determine whether the presence of age-related macular degeneration (AMD) decreases the risk of diabetic retinopathy. METHODS: This was a retrospective, case-cohort study performed in patients with a systemic diagnosis of diabetes at a tertiary health care center from May 2011 to April 2020. A total of 43,153 patients (1,024 AMD patients and 42,129 non-AMD patients) were included in the analysis. A total of 1,024 age and diabetes mellitus (DM) duration-matched controls were chosen from the non-AMD group for risk factor analysis. The severity of diabetic retinopathy was compared between the patients with AMD and the patients without AMD. RESULTS: Out of the enrolled 43,153 diabetic patients, 26,906 were males and 16,247 were females. A total of 1,024 patients had AMD and 42,129 had no AMD. The mean age of the cohort was 58.60 ± 0.09 years. The overall prevalence of DR was noted to be 22.8% (9,825 out of 43,153 eyes). A significantly lower prevalence of diabetic retinopathy (DR) (23% in non-AMD, 11.4% in AMD, OR = −0.43, P < 0.001), non-proliferative diabetic retinopathy (NPDR) (12% in non-AMD, 8.2% in AMD, OR = −0.66, P < 0.001), and proliferative diabetic retinopathy (PDR) (11% in non-AMD, 3.2% in AMD, OR = −0.27, P < 0.001) was seen in the AMD patients. No significant difference was seen between the dry and wet AMD. On multivariate logistic regression analysis, the lower age, absence of AMD, and male gender were associated with a higher risk of PDR. CONCLUSION: The presence of AMD was noted to statistically reduce the risk of DR. Our results may be useful in the field of resource allocation and awareness of DR.