A four-year follow-up study on the incidence of diabetic retinopathy in older onset diabetes mellitus.

Out of 369 diabetic patients with an age at onset of diabetes > or = 30 years previously studied, 325 (88%) were included in an ophthalmological follow-up examination 4 years later. In patients treated with oral drugs at baseline, the incidence of any type of retinopathy was 30.8% and of severe retinopathy 5.7%. All patients who developed severe retinopathy received insulin during the follow-up period. At baseline, duration of diabetes, diastolic blood pressure, and signs of nephropathy (p < 0.05 in all cases) as well as degree of metabolic control (p < 0.01) differed between patients who developed retinopathy and those who did not. At follow-up, there were no longer any differences regarding degree of metabolic control and diastolic blood pressure. In patients treated with insulin at baseline, the incidence of any type of retinopathy was 41.0% and of severe retinopathy 16.1%. At baseline, duration of diabetes (p < 0.01), degree of metabolic control, and insulin dosage (p < 0.05 in both cases) differed between patients who developed retinopathy and those who did not. At follow-up, there was no longer any difference in insulin dosage.