Prevalence and risk factors for Diabetic Retinopathy In an Urban Chinese population: The Singapore Chinese Eye Study

Abstract

Purpose: To describe the prevalence and risk factors for diabetic retinopathy (DR) in an urban Chinese population in Singapore

Methods: A population-based study was conducted in 3,353 (response rate: 72.8%) Chinese, aged 40-80+ years, living in Singapore. Participants underwent a comprehensive ocular examination. Diabetes was defined in persons with random plasma glucose ≥200mg/dl (11.1mmol/l), hemoglobin A1c[hbA1c] ≥6.5%, self-reported physician-diagnosed diabetes, or the use of glucose lowering medication. Retinal photographs, taken from both eyes, were graded for the presence and severity of DR using the modified Airlie House classification system. Vision-threatening diabetic retinopathy (VTDR) was defined as severe non-proliferative DR, proliferative DR or clinically significant macular edema. Age-standardized prevalence estimates were calculated using the 2010 Singapore adult population.

Results: The age-standardized prevalence of diabetes was 16.3% (95% confidence interval [CI] 14.9,17.8), with 581 persons who had diabetes and gradable photos for analysis of DR. The age-standardized prevalence was 26.1% (95% CI 20.8, 32.7) for any DR, 6.0% (95% CI 3.7, 9.8) for any macular edema and 7.0% (95% CI 4.5, 10.9) for VTDR. The age-standardized prevalence for minimal DR, mild DR, moderate DR and severe or worse DR was 8.6%, 5.9%, 7.3% and 4.2% respectively. In multivariate analysis, independent risk factors for any DR were, longer diabetes duration (odds ratio [OR] 2.38, 95% CI 1.83, 3.09; per decade increase), higher hbA1c (OR 1.22, 95% CI 1.04, 1.42 per % increase), higher systolic blood pressure (OR 1.25, 95% CI 1.11, 1.41; per 10mmHg increase), chronic kidney disease (OR 2.36, 95% CI 1.22, 4.56), lower education (OR 2.47, 95% CI 1.42, 4.29; elementary school or lower). Age (OR 0.59, 95% CI 0.44, 0.79; per decade increase) and axial length (OR 0.79, 95% CI 0.65, 0.95 per mm increase) were protective against any DR. Both VTDR and macular edema were associated with longer diabetes duration, higher hbA1c and higher systolic blood pressure. Older age was protective in macular edema.

Conclusions: One quarter of Chinese persons with diabetes in Singapore have DR and 1 in 14 have vision-threatening stages of retinopathy. Similar to other studies, classic risk factors explain the majority of risk of DR and axial length was found to be protective.

Keywords: 499 diabetic retinopathy • 463 clinical (human) or epidemiologic studies: prevalence/incidence • 464 clinical (human) or epidemiologic studies: risk factor assessment