Researchers from the Diabetes Control and Complications Trial (DCCT), and the Epidemiology of Diabetes Interventions and Complications (EDIC) Research Group, have published comprehensive findings indicating that individualized retinal screening could save significant resources by reducing the frequency of eye exams without delaying diagnosis. The research, published in the New England Journal of Medicine (N Engl J Med 376; 16, April 20, 2017), claims that scheduling retinal examinations in relation to the stage of retinopathy, and the mean glycated hemoglobin levels, result in an average decrease of 10.7 clinical visits, a 58% reduction in the number of visits compared to an annual screening protocol. Based on such metrics, the authors estimated the cost savings for eye screening would be approximately $1 billion over 20 years, representing a 43.4% reduction when compared to routine screening strategies.
The research group had followed a type 1 diabetes cohort of patients for more than 30 years, facilitating the collection of significant fundus photography data, including the time intervals between diabetes diagnosis and stages of diabetic retinopathy and disease progression. Analyzing the substantial data sets allowed the researchers to establish an evidence-based screening schedule that could detect vision-threatening changes by matching the stage of disease to the probability of progression over time. The goal of the research was to identify a schedule of screening that permitted timely detection of retinopathy and progression, with a more efficient use of resources. Analysis of 23,961 retinopathy examinations showed that the probability of progression to proliferative diabetic retinopathy (PDR), or clinically significant macular edema (CSME) was limited to approximately 5% between retinal screening examinations at 4 years among patients who had no retinopathy, 3 years among those with mild retinopathy, 6 months among those with moderate retinopathy, and 3 months among those with severe non-proliferative diabetic retinopathy. The researchers additionally found that the risk of progression was closely related to mean glycated hemoglobin levels. The risk of progression from no retinopathy to PDR, or CSME, was 1.0% over 5 years among patients with a glycated hemoglobin level of 6%, compared with 4.3% over 3 years for patients with a glycated hemoglobin level of 10%.
To encourage practical uptake of the findings and extend the proposal into clinical practice, the authors created a web application, the “Optimal Frequency Retinopathy” tool (https:/ /extapps.bsc.gwu.edu/shinypub/edic/retinopathy/) which provides a simple algorithm showing the cumulative incidence of a late-stage retinopathy for a patient on the basis of their current disease state and average glycated hemoglobin level. Using the proposed system the authors suggest that, on average, the time during which a severe late stage retinopathy would go undetected would be 2.3 months shorter using the evidence- based schedule instead of yearly screening. Commenting on the study, the authors concluded their publication stating that that a “practical, evidence based, individualized screening schedule would provide a shorter time during which proliferative retinopathy or macular edema would go undetected and would require substantially fewer examinations than the currently recommended annual screening.”