Microalbuminuria and low hemoglobin as risk factors for the occurrence and increasing severity of diabetic retinopathy

AIM To assess the influence of urinary microalbuminuria and hemoglobin concentration on the occurrence and severity of diabetic retinopathy (DR), clinically significant macular edema (CSME) and hard exudate formation. MATERIALS AND METHODS In this prospective cross-sectional study carried out over a period of 2 years, type 2 diabetic patients seeking ocular evaluation for DR were assessed for presence and severity of DR, presence of hard exudates and CSME. Retinal findings were correlated to severity of microalbuminuria, hemoglobin concentration and other systemic risk factors using linear regression analysis. RESULTS Three hundred and six patients were included in the study. DR of any grade was seen in 132 (43%) patients, hard exudate formation in 93/306 (30.4%) patients, CSME in 50/306 (16.3%) patients and proliferative DR in 26/306 (8.5%) patients. Duration of diabetes (P < 0.001), microalbuminuria (P < 0.001) and low hemoglobin (P = 0.001) were found to be highly significant risk factors for the development and increasing severity of DR as well as for CSME and hard exudate formation. CONCLUSION Microalbuminuria and low hemoglobin are strong predictors for DR, CSME and hard exudate formation in type 2 diabetics even after correcting for duration of diabetes and other systemic risk factors. Although not directly involved in the pathogenesis, microalbuminuria can help in identifying patients at risk for more severe diabetic eye disease. Microalbuminuria warrants intensive monitoring of both retinal and renal status. The hemoglobin levels should be monitored regularly in diabetic patients to detect and treat anemia, thereby reducing one risk factor for DR.