External validation of a risk assessment model to adjust the frequency of eye-screening visits in patients with diabetes mellitus

Aims: To validate a sight-threatening diabetic retinopathy (STDR) risk assessment model to adjust the frequency of eye-screening visits in patients with diabetes mellitus. Methods: Retrospective follow-up study of patients with diabetes mellitus attending a diabetes center. Anonimyzed data on gender, type and duration of diabetes, HbA1c, blood pressure and the presence and grade of diabetic retinopathy were gathered to estimate risk for STDR for each individual's worse eye over time by means of a prediction model. Receiver operating characteristics (ROC) analysis was performed to determine the diagnostic ability of the model, and a calibration graph was done to see the model fit. Results: 508 screening intervals were analyzed, median diabetes duration was 10 years, 87% were type 2 diabetes mellitus, and 3.1% developed STDR before the next screening visit. The area under the ROC curve was 0.74, and the calibration graph showed that model had a good fit. The reduction in screening frequency was 40% compared with fixed annual screening. Conclusions: Current prediction model used to estimate the risk of developing STDR in patients with diabetes performed well. A personalized screening frequency for diabetic retinopathy could be implemented in practice. (C) 2015 Elsevier Inc. All rights reserved.