Geographical disparities in the prevalence of diabetic retinopathy in two contiguous states of South India

This study aims to examine geographic disparities in the prevalence of Diabetic Retinopathy (DR) and Vision-Threatening Diabetic Retinopathy (VTDR) between two neighboring South Indian states—Tamil Nadu (TN) and Kerala (KL). A retrospective cross-sectional analysis was conducted, utilizing medical records from five major tertiary hospitals focusing on Type II Diabetes Mellitus (DM) patients aged over 40, from January 2016 to January 2018. Data from 213,440 patients with Type II DM were analyzed, including variables such as age, sex, duration of diabetes, and distance traveled to healthcare facilities. Propensity score matching (PSM) was employed to adjust for demographic, clinical, and spatial differences. Falsification tests was performed using Age-Related Macular Degeneration (ARMD) and Macular Hole (MH) as control outcomes. The prevalence of DR and VTDR was 21.22 % and 10.87 % in the KL cohort, compared to 8.47 % and 3.26 % in the TN cohort, respectively. Adjusted logistic regression, incorporating demographic, clinical, and spatial factors, showed that the KL cohort had an odds ratio of 1.912 (95 % CI: 1.810–2.020) for DR and 2.073 (95 % CI: 1.922–2.236) for VTDR. After PSM for both individual and spatial factors, the odds ratios for the KL cohort were 1.845 (95 % CI: 1.724–1.977) for DR and 1.917 (95 % CI: 1.746–2.105) for VTDR. This study identifies regional disparities in DR and VTDR between TN and KL. These findings suggest the need for further research and targeted interventions to better understand and address the factors contributing to these disparities. This study investigates the significant geographical disparities in the prevalence of Diabetic Retinopathy (DR) between Tamil Nadu and Kerala, two neighboring South Indian states with similar healthcare infrastructures. Analyzing over 200,000 patient records using robust statistical methods, including propensity score matching, the study reveals stark regional differences in DR prevalence. These findings emphasize the need for tailored public health interventions and further research into genetic, socioeconomic, and environmental determinants of diabetic eye diseases.