Prognostic factors and retinopathy in type 1 diabetics in Iceland.

Prognostic factors, particularly those related to metabolic control, were analysed individually over a period of 12 months prior to fundus photography in 149 type 1 (insulin-dependent, ketosis-prone) diabetics in Iceland. Patients without retinopathy in their first 20 years of diabetes visited the Diabetic Clinic significantly more frequently than those with retinopathy (p less than 0.05). Mean blood sugar values and mean per cent body weight did not differ between patients with or without retinopathy. Few between patients with or without retinopathy. Few patients were obese. In patients with 5-9 years' duration of diabetes, retinopathy was first seen after 7.7 +/- 0.3 years (mean +/- SEM). Those with retinopathy were significantly older at the time of the diagnosis of diabetes than those without eye lesions (p less than 0.025), a tendency also noted in those with 10-19 years' duration (p less than 0.10). Conversely, patients without retinopathy after diabetes for 20 years or more were significantly older at the time of diagnosis (p less than 0.02). They used significantly less insulin daily than those with retinal lesions (p less than 0.005) and 70% were females. Subsequently, a significant (p less than 0.047) male excess was found to characterize a group of patients with proliferative retinopathy.