Epidemiological survey of diabetic retinopathy in Shunyi district of Beijing

Abstract

Background There are no noticeable symptoms in early stages of diabetic retinopathy(DR)and the detection of presymptomatic DR remains challenging. Therefore, data on the prevalence and progress of DR will help in prevention and treatment programs in China. Objective This study was to survey the prevalence and risk factors of diabetic retinopathy( DR ) in a population aged 40 years or older in the Shunyi district of Beijing city.Methods A cross-sectional study was designed. Cluster sampling was used to randomly select 4167 (91.6%)individuals aged ≥40 years in 24 clusters in the Shunyi district of Beijing city in China. The Questionnaire data,including general information, living habits, present history, past history, family history, education level etc., were obtained from each subjects. The height, body weight and blood pressure were examined, and slit-lamp examination, direct ophthalmoscopy,indirect ophthalmoscopy and nonmydriatic fundus photography were performed during the study duration. Diabetic mellitus (DM)was diagnosed and graded according to the criteria of Early Treatment Diabetic Retinopathy Study Research Group(ETDRS). The associated factors with DR were analyzed byx2 test,trend x2 test,and multivariate Logistic regression analysis. This protocol was approved by the Ethic Committee of Peking University. Informed consent was obtained from each individual prior to the survey. Results A total of 4167 ( 91.6% )individuals were examined from the 4549 samples with a response rate of 86. 4%. This study showed a prevalence of 29. 2% for DR, 5.4% for sight-threatening diabetic retinopathy ( STDR), and 1.3% for prolifrative retinopathy (PDR) in type 2 DM subjects. Of the type 2 DM subjects,0. 4% (4/445)had social blindness( VA＜0. 1 ) ,and 6. 3% (28/445) presented with visual impairment (VA ＜ 0. 3 )in bilateral eyes. Univariate Logistic regression analysis indicated that insulin therapy ( P = 0.011 ) and lower body mass index ( BMI, kg/m2 ) ( P = 0. 022 ) appeared to be significantly associated with DR, and the multivariate Logistic regression analysis demonstrated that longer duration of diabetes( P＜ 0. 01 ) , increased fasting glucose ( P ＜ 0.01 ) and lower education level ( P = 0. 031 ) were significant independent predictors of DR. Conclusion The prevalence of DR is lower among diabetic Chinese aged ≥ 40 years than those of matched population in Western countries. Lower BMI and insulin therapy were the significantly associated factors of DR, and a longer duration of disease and higher fasting glucose level are independent risk factors of DR. Education attainment is important for the DM patients as a protective factor of DR. Key words: Diabetic retinopathy; Epidemiology; Prevalence; Risk factor; Cross-sectional study