UKPDS 50: Risk factors for incidence and progression of retinopathy in Type II diabetes over 6 years from diagnosis

Aims/hypothesis. To determine risk factors related to the incidence and pro gression of diabetic retinopathy over 6 years from diagnosis of Type II (no n-insulin-dependent) diabetes mellitus. Methods. This report describes 1919 patients from within the United Kingdom Prospective Diabetes Study (UKPDS), with retinal photographs taken at diag nosis and 6 years later and with complete data available. Photographs were centrally graded for lesions of diabetic retinopathy using the modified Ear ly Treatment of Diabetic Retinopathy Study Final scale. Risk factors were a ssessed after 3 months diet from the time of diagnosis of diabetes. Patient s were seen every 3 months in a hospital setting. Biochemical measurements were done by a central laboratory. End points of vitreous haemorrhage and p hotocagulation were confirmed by independent adjudication of systematically collected clinical data. The main outcome measures were incidence and prog ression of retinopathy defined as a two-step Early Treatment of Diabetic Re tinopathy Study (ETDRS) final scale change. Results. Of the 1919 patients, 1216 (63%) had no retinopathy at diagnosis. By 6 years, 22% of these had developed retinopathy, that is microaneurysms in both eyes or worse. In the 703 (37%) patients with retinopathy at diagno sis, 29% progressed by two scale steps or more. Development of retinopathy (incidence) was strongly associated with baseline glycaemia, glycaemic expo sure over 6 years, higher blood pressure and with not smoking. In those who already had retinopathy, progression was associated with older age, male s ex, hyperglycaemia las evidenced by a higher HbA(1c)) and with not smoking. Conclusion/interpretation. The findings re-emphasise the need for good glyc aemic control and assiduous treatment of hypertension if diabetic retinopat hy is to be minimised.