Prevalence of diabetic retinopathy in self-reported diabetics among various ethnic groups and associated risk factors in North-East India: A hospital-based study

PURPOSE: To describe the prevalence and severity of diabetic retinopathy (DR) among different ethnic groups of North-East India and to study the associated risk factors. METHODS: In this hospital based cross sectional study 7,133 individuals among the age group of 20-79 years, attending the OPD, were screened for presence of Diabetes Mellitus (DM) (HbA1c >7% or previously diagnosed). Among them, 780 (10.94%) had diabetes; they were evaluated for presence of any retinopathy (based on fundus photograph and fluorescein angiography), its grade (based on International DR severity scale), and risk factors. DR patients were further grouped into different ethnicities (Assamese, Bengali, minor tribes, and other immigrants). RESULTS: Of the 780 patients with diabetes, 58 patients had type 1 DM and 722 patients had type 2 DM. The overall prevalence of DR was 30.0% with vision-threatening retinopathy and maculopathy being 10.00% and 4.49%, respectively. The prevalence of retinopathy range was the highest in the immigrants’ group (50.00% among type 1 DM and 44.93% among type 2 DM) and lowest in the tribal's groups (16.67% among type 1 DM and 22.35% among type 2 DM). The risk factors showing significant association with DR were longer diabetes duration, older age, family history of diabetes, higher HbA1c level, associated hypertension, hypertriglyceridemia, and pregnancy state (P value <0.05). CONCLUSION: Every third patient with diabetes had some form of DR with Vision Threatening DR (VTDR) affecting every tenth patient. There was also a wide variation in the prevalence of DR among ethnic groups and this difference could not be attributed to variation in the known measurable risk factors among different ethnic groups, thus signifying the role of ethnicity in occurrence and severity of DR.