The 16-year incidence, progression and regression of diabetic retinopathy in a young population-based Danish cohort with type 1 diabetes mellitus: The Danish cohort of pediatric diabetes 1987 (DCPD1987).

The aim was to investigate the long-term incidence of proliferative diabetic retinopathy (PDR), and progression and regression of diabetic retinopathy (DR) and associated risk factors in young Danish patients with Type 1 diabetes mellitus. In 1987-89, a pediatric cohort involving approximately 75 % of all children with Type 1 diabetes in Denmark <19 years of age was identified (n = 720). In 1995, 339 (47.1 %) were re-studied with retinopathy graded and all relevant diabetic parameters assessed. Of those, 185 (54.6 %) were evaluated again in 2011 for the same clinical parameters. All retinal images were graded using modified early treatment of DR study for 1995 and 2011. In 1995, mean age was 21.0 years and mean diabetes duration 13.5 years. The 16-year incidence of proliferative retinopathy, 2-step progression and 2-step regression of DR was 31.0, 64.4 and 0.0 %, respectively, while the incidence of DR was 95.1 %. In a multivariate logistic regression model, progression to PDR was significantly associated with 1995 HbA1c (OR 2.61 per 1 % increase, 95 % CI 1.85-3.68) and 1995 diastolic blood pressure (OR 1.79 per 10 mmHg increase, 95 % CI 1.04-3.07). Two-step progression of DR was associated with male gender (OR 2.37 vs. female, 95 % CI 1.07-5.27), 1995 HbA1c (OR 3.02 per 1 % increase, 95 % CI 2.04-4.48) and 1995 vibration perception threshold (OR 1.19 per 1 Volt increase, 95 % CI 1.02-1.40). In conclusion, one in three progressed to PDR and two in three had 2-step progression despite young age and increased awareness of the importance of metabolic control. After 30 years duration of diabetes, the presence of DR is almost universal.