Early detection of type 2 diabetes mellitus and screening for retinopathy are associated with reduced prevalence and severity of retinopathy.

PURPOSE: To explore whether the prevalence and severity of retinopathy differ in diabetes cohorts diagnosed through screening as compared with conventional health care. METHODS: A total of 257 diabetes patients, 151 detected through screening and 106 through conventional clinical care, were included. Retinopathy was evaluated by fundus photography. The modified Airlie House adaptation of the Early Treatment Retinopathy Study protocol was used to grade the photographs. Averages of clinically collected fasting blood glucose (FBG), blood pressure and body mass index values were compiled from diabetes diagnosis until the eye examination. Blood chemistry, smoking habits and peripheral neuropathy were assessed at the time of the eye examination. RESULTS: Among the screening-detected patients, 22% had retinopathy as compared to 51% among those clinically detected (p < 0.0001). In a multivariate analysis, patients with retinopathy were more likely to have increased average FBG (OR 1.42, 95% CI 1.19-1.70 per mmol/l) and peripheral neuropathy (OR 2.75, 95% CI 1.40-5.43), but less likely to have screening-detected diabetes (OR 0.31, 95% CI 0.17-0.57). Similar results were found using increasing severity grade of retinopathy as outcome. The cumulative retinopathy prevalence for the screening-detected diabetes cohort as compared with the clinically diagnosed cohort was significantly lower from 10 years' follow-up and onwards (p = 0.0002). CONCLUSIONS: Among patients with screening-detected diabetes, the prevalence of retinopathy and increasing severity of retinopathy were significantly lower than among those who had their diabetes diagnosed through conventional care, even when other risk factors for retinopathy such as duration, hyperglycaemia and blood pressure were considered. Early detection of diabetes reduces prediagnostic time spent with hyperglycaemia. In combination with early and regular screening for retinopathy, more effective prevention against retinopathy can be provided.

The prevalence of retinopathy in subjects with and without type 2 diabetes mellitus.

PURPOSE: To evaluate the prevalence of and risk factors for, retinopathy in a geographically defined population with type 2 diabetes mellitus compared with a control group of subjects without diabetes, matched by age, sex and residence in order to find the retinopathy attributable to type 2 diabetes. METHODS: The study populations are, on one hand, a prevalence cohort of subjects with type 2 diabetes resident in the community of Laxå, Sweden, and on the other a control group, matched by age, gender and residence with those with a diagnosis of type 2 diabetes mellitus. Retinopathy was graded from fundus photographs using a modification of the Early Treatment Retinopathy Study (ETDRS) adaptation of the modified Airlie House classification of diabetic retinopathy (DR). RESULTS: Any retinopathy was found in 34.6% in the type 2 diabetes cohort and in 8.8% in the control group without diabetes. Among the diabetic patients, any retinopathy was significantly associated with duration of diabetes (p = 0.0001), HbA1c (p = 0.0056), systolic blood pressure (p = 0.0091) and lower serum cholesterol (p = 0.0197) in multivariate logistic regression analyses. Having retinopathy in the control group was associated only with systolic blood pressure (p = 0.0014) in logistic regression analysis. CONCLUSIONS: The prevalence of retinopathy among patients with type 2 diabetes in Laxå, Sweden, was similar or somewhat lower compared with other studies in the Nordic countries. The prevalence of retinopathy in a control group without diabetes equalled numbers from population studies worldwide. Our study indicates that the retinopathy that can be attributed to hyperglycaemia in the diabetic state is less common than is usually accounted for. A considerable fraction of retinopathy in subjects with diabetes may instead be due to other factors such as hypertension and should thus be treated correspondingly.