Prevalence and progression rate of diabetic retinopathy in type 1 diabetes patients in correlation with the duration of diabetes

AIMS We examined prevalence and progression of retinopathy in dependence on diabetes duration in order to estimate the probability of progression. PATIENTS/METHODS In a retrospective cohort-analysis from an academic outpatient department of endocrinology and metabolic diseases we analyzed 17461 consultations of 4513 patients with DM2 from 1987 to 2014. 50.3% of the patients (n=2272) had at least one documented result of funduscopy. RESULTS 25.8% of the patients had retinopathy (20.2% non-proliferative, 4.7% proliferative, 0.7% were not classified, 0.1% blindness). The prevalence of retinopathy in dependence on diabetes duration was 1.1% at diagnosis, 6.6% after 0<5 years, 12% after 5<10 years, 24% after 10<15 years, 39.9% after 15<20 years, 52.7% after 20<25 years, 58.7% after 25<30 years and 63% after ≥30 years. In a subset of 586 (25.7%) patients with retinal photography of 3 consecutive years 7.0% showed deterioration after one and 12.2% after two years; 2.6% improved after one and 2.8% after two years. 201 (34.3%) of this group had<10 years diabetes and lower deterioration (4.5% worsened after one and 9.5% after two years). Their retinopathy mainly transformed from no retinopathy to non-proliferative. Four patients (2.0%) developed proliferative retinopathy. CONCLUSIONS/INTERPRETATIONS Within the first 10 years of diabetes duration, the prevalence of retinopathy is low and the progression infrequent. Most patients have a non-proliferative form which can be reversible and rarely requires interventions. Patients with DM2 without retinopathy and good glycaemic control do not run into additional risk from expanding funduscopy intervals to biennial.