Prevalence and associated factors of diabetic retinopathy. The Beijing Eye Study 2006

Background To evaluate the prevalence and associated factors of diabetic retinopathy in adult Chinese with diabetes mellitus. Methods The Beijing Eye Study 2006 is a population-based cross-sectional study that included 3,251 (73.2%) subjects (aged 45+ years) out of 4,439 subjects originally participating in the Beijing Eye Study 2001. Diabetes defined as fasting glucose concentrations >= 7.0 mmol/L or self-reported diagnosis of diabetes was detected in 381/3,251 (12.9%) subjects. Diabetic retinopathy was defined by the presence of at least one microaneurysm in the diabetic subjects according to the Early Treatment of Diabetic Retinopathy Study (ETDRS). Results Gradable fundus photographs were available for 362 (95.0%) subjects. Diabetic retinopathy was detected in 101 subjects (27.9%). Most of the diabetic retinopathy was of the mild type (74/101; 73%). Severe non-proliferative or proliferative diabetic retinopathy was present in 16 (16%) subjects, and clinically significant macular edema in four (4%) subjects. Presence of diabetic retinopathy was significantly associated with rural region (Odds ratio (OR): 3.52), duration of diabetes mellitus (OR: 1.08), fasting plasma glucose concentration (OR: 1.14), type of diabetes treatment (OR: 2.09), and marginally significantly, with hyperopic refractive error (OR: 1.13; P=0.08). The stage of diabetic retinopathy was associated with rural region (P < 0.001), known duration of diabetes (P=0.001), type of diabetes treatment (P=0.001), concentrations of high-density lipoproteins (P=0.004), and fasting glucose concentrations (P=0.002). Conclusions Prevalence of diabetic retinopathy among adult diabetic Chinese was about 27.9%. The stage of retinopathy was mild in 75% of the subjects with diabetic retinopathy. Associated factors were diabetes duration, diabetic treatment type, low metabolic control, rural region, and marginally hyperopia.