Diabetic Retinopathy in 2011: Further Insights From New Epidemiological Studies and Clinical Trials

Diabetic retinopathy (DR) is a common and specific microvascular complication of diabetes and one of the leading global causes of preventable blindness. Population-based studies suggest that about one-third of the diabetic population have signs of DR and approximately one-tenth have vision-threatening stages of retinopathy, such as diabetic macular edema and proliferative retinopathy (1,2). Notwithstanding its effects on vision, DR is costly (3), substantially impacts on the patient's quality of life (4), and is linked with a greater risk of life-threatening systemic vascular complications (5). Because blindness from DR is preventable from both public health screening and clinical management perspectives, it is important to precisely identify persons at risk for developing DR and those most likely to progress to severe vision-threatening stages. In this issue of Diabetes Care , Zavrelova et al. (6) present a fascinating and informative article that discusses people with diabetes having distinct developmental patterns of DR and that there may be specific risk factors associated with different patterns of progression. From a large group of patients with type 2 diabetes ( N = 3,343), the authors identified five clusters of developmental patterns of DR. The largest (cluster A) included patients who did not develop any form of DR over a 6-year period (“persistent no retinopathy”). Cluster B included patients with a high probability of a mild form of DR, which disappeared over time and thus are not at risk for vision loss. Two progressive clusters (C and D) were identified and differed from each other in severity and in speed of developing retinopathy. Finally, a fifth cluster (E) consisted of patients who had persistent proliferative DR, including previous laser treatment. Perhaps the most important finding was that almost 90% of this population (cluster A) were …