Determination of diabetic retinopathy prevalence and associated risk factors in Chinese diabetic and pre-diabetic subjects: Shanghai diabetic complications study.

BACKGROUND: The prevalence of diabetic retinopathy is not well studied in the Chinese pre-diabetic population, also known as impaired glucose regulation. Hence, we investigated the prevalence of and risk factors associated with retinopathy in diabetic and pre-diabetic subjects from Chinese communities.
METHODS: A total of 3736 Chinese subjects were recruited from urban communities in Shanghai. The participants were classified as normal glucose tolerance, impaired glucose regulation (IGR) and diabetes based on the 75 g oral glucose tolerance test. The levels of diabetic retinopathy (DR) were assessed with non-mydriatic retinal photographs according to the Diabetic Retinopathy Disease Severity Scale.
RESULTS: The prevalence of diabetic retinopathy in patients with diabetes and impaired glucose regulation subjects was 9.4% and 2.5%, respectively. In subjects with IGR, hypertension (odds ratio: 3.54, p = 0.028), including elevated systolic and diastolic blood pressure and obesity (odds ratio: 3.53, p = 0.028) were significantly associated with diabetic retinopathy after age and sex adjustments. The factors associated with retinopathy in diabetes included diabetes duration, blood glucose levels, glycated hemoglobin levels, and the presence of albuminuria. Diabetic retinopathy was significantly associated with fasting plasma glucose in known diabetes, whereas in newly-diagnosed subjects, diabetic neuropathy was closely correlated to postprandial plasma glucose.
CONCLUSIONS: Hyperglycemia was a strong risk factor for diabetic retinopathy. In pre-diabetic subjects, diabetic retinopathy was also associated with hypertension and obesity.