Thailand Diabetes Registry Project: Prevalence of diabetic retinopathy and associated factors in type 2 diabetes mellitus

Abstract

Objective: To determine the prevalence of and factors associated with Diabetic Retinopathy (DR) in type 2 diabetes in Thailand. Material and Method: A cross-sectional, multicenter, hospital-based study was carried out between April and December 2003. Diabetic patients in diabetic clinics of 11 tertiary centers in Thailand were registered. Retinal examination of the participants was performed by ophthalmologists. Results: 7,119 of 9,419 (75.6%) diabetic patients received retinal examination using direct ophthalmoscopy after full dilatation of pupils. 6,707 cases were type 2 diabetic patients. The prevalence of DR was 31.4% (N = 2105) which consisted of Non-Proliferative DR (NPDR) 22% (N = 1475), Proliferative DR (PDR) 9.4% (N = 630). Patients with DR were significantly older, had longer duration of diabetes, and higher Fasting Plasma Glucose (FPG), HbA1c, serum LDL, serum Tri Glyceride (TG) and systolic Blood Pressure (BP) levels than those without DR. Nephropathy (which consisted of positive microalbuminuria, proteinuria or renal insufficiency). The patients with DR presented in a significantly higher number of than those without DR. A. The factors associated with DR (adjusted Odds Ratio (OR) [95% CI]) were 1) duration of diabetes 1.4 [1.04-1.82] for duration of 5-9.9 years, 1.9 [1.47-2.58] for duration of 10-14.9 years, 2.9 [2.11-3.95] for duration of 15-19.9 years, 3.5 [2.58-4.79] for duration of ≥ 20 years when compared with duration of diabetes of less than 5 years, 2) latest HbA1c > 7% (1.5 [1.24-1.88]) when compared with HbA1c ≤ 7%, 3) systolic BP > 140 mmHg (1.4 [1.18-1.71]) when compared with systolic BP ≤ 140 mmHg, 4) nephropathy status i.e. positive microalbuminuria (1.5 [1.21-1.93]), positive proteinuria (1.9 [1.45-2.35]) and renal insufficiency (3.3 [2.29-4.70]) when compared with no nephropathy. Conclusion: Diabetic retinopathy was present in about one third of type 2 diabetic patients in Thailand. The authors found the factors associated with DR were duration of diabetes, latest HbA1c level, systolic BP and diabetic nephropathy. Regular screening for DR and more aggressive management of associated factors should be done to reduce the prevalence of DR.