A study published in the New England Journal of Medicine describes a model estimating the probability of progression of diabetic retinopathy, a serious condition that can result in vision loss. New recommendations are based on individualized eye screening schedules and would provide a cheaper and more effective detection approach to reducing incidences of undiagnosed progressive diabetic retinopathy.
Retinopathy is a disease of the retina that is frequently associated with type I diabetes. Diabetic retinopathy is the most common cause of vision loss in adults in the United States. The risk of disease progression can be significantly reduced by proper glycemic management and timely treatment. Therefore, screening is of the highest importance for prevention of diabetes I associated vision loss.
Current recommendations for eye screening in patients with type I diabetes includes annual retina examination 3-5 years after diagnosis of diabetes. In an attempt to establish an evidence-based screening schedule, this study examined retinal photographs gathered over more than 30 years from the Diabetes Control and Complication Trial (DCCT) and the Epidemiology of Diabetes Interventions and Complications (EDIC) study. These studies examined about 1400 diabetic patients for glycemic management related disease complications.
The DCCT conducted from 1983 through 1993 and the follow-up EDIC study (1994 – 2012) followed a cohort of type I diabetic patients with regularly scheduled retina examinations. The DCCT involved 1,441 volunteers, ages 13 to 39, with type 1 diabetes and no, or only early signs of, diabetic eye disease. The trial took place in 29 medical centers in the United States and Canada. The volunteers were randomly assigned to receive intensive glycaemia therapy or conventional diabetes therapy aimed at preventing hyperglycemia and hypoglycemia with no specific glucose targets. The study compared the effects of standard control of blood glucose versus intensive control on the complications of diabetes. Intensive control meant keeping hemoglobin A1C levels as close as possible to the normal value of 6 percent or less. The A1C blood test reflects a person’s average blood glucose over the last 2 to 3 months. Overall, the DCCT study showed that keeping blood glucose levels as close to normal as possible slows the onset and progression of the eye, kidney, and nerve damage caused by diabetes.
The study also analyzed a collection of retina photographs gathered through the DCCT and EDIC studies and calculated the frequency of retina screening required to limit the probability of progression to clinically significant retinopathy to approximately 5%. The model reveals a requirement for screening intervals of 4 years for patients with no baseline retinopathy, 3 years among those with mild retinopathy, 6 months among those with moderate retinopathy, and 3 months among those with severe diabetic retinopathy. This frame of screening reduces the number of required retina examinations, resulting in substantial cost saving and reduces the time period during which the severe retinopathy remains undiagnosed, improving chances to prevent vision loss in diabetes patients.
Written By: Bella Groisman, PhD