Risk Factor Analysis of Diabetic Retinopathy Diagnosed with Non-mydriatic Fundus Camera: KNHANES V

Purpose: To clarify the relationship between various factors (sociodemographic factors, health behavioral risk factors and health status, and diabetic factors) related to diabetic retinopathy and to suggest improvements regarding the associated medical examination. Methods: The subjects were 1,444 diabetic patients diagnosed in the 5th Korean National Health and Nutrition Examination Survey (KNHANES), aged 19 years or older, who underwent non-mydriatic fundus photography. The criteria for diagnosing diabetes were a fasting glucose level >= 126 mg/dL and a previous diagnosis of diabetes or currently undergoing treatment. The diagnosis of diabetic retinopathy followed the modified Airlie House classification. Univariate and multivariate analyses of diabetic retinopathy were performed. Results: Among the 1,444 patients who were diagnosed with diabetes, 277 had diabetic retinopathy; the prevalence rate was 19.18%. The higher the body mass index, the lower the risk of diabetic retinopathy by 0.924 times (p = 0.001; 95% confidence interval [CI], 0.883-0.966). The longer the duration of diabetes, the greater the risk of diabetic retinopathy; the prevalence period group of more than 11 years had a 26.025-fold higher risk than the newly diagnosed group (p < 0.001; 95% CI, 10.840-62.482). The risk of diabetic retinopathy increased with the hemoglobin A1c (HbA1c) level; the risk was 5.973-fold higher in the group with HbA1c above 11.0% (p < 0.001; 95% CI, 2.984-11.956) compared with the group with HbA1c < 6.0%. The risk of diabetic retinopathy was 2.050-fold greater with insulin injections (p = 0.003; 95% CI, 1.284-3.275). Conclusions: The risk of diabetic retinopathy was higher in patients with a longer duration of diabetes, a high HbA1c level, and in those using insulin. These findings highlight the need for early education and ophthalmologic examinations for at-risk patients.