Decline in the Cumulative Incidence of Severe Diabetic Retinopathy in Patients With Type 1 Diabetes

OBJECTIVE: To determine if the cumulative incidence of severe retinopathy in patients with type 1 diabetes has changed. RESEARCH DESIGN AND METHODS: The study looked at 3,781 patients diagnosed with type 1 diabetes (1939–2005), median age at onset 13 (interquartile range [IQR] 9–21) years, and duration of diabetes 19 (IQR 13–27) years. The severe retinopathy was based on a history of laser treatment. Patients were divided into <1975, 1975–1979, 1980–1984, and ≥1985 cohorts according to the diagnosis of diabetes. RESULTS: The cumulative incidence of severe retinopathy has declined (P < 0.0001). After 20 years of duration, the cumulative incidence was 23% (95% CI 21–25) and 33 (30–35) in the earliest cohorts, 18 (15–21) in the next cohort, and 6 (4–9) in the recent cohort. After 30 years, the cumulative incidence was 52 and 48% in the earliest cohorts, while it was 62% after 40 years in the earliest cohort. CONCLUSIONS: The cumulative incidence of severe retinopathy has declined in patients with type 1 diabetes.