Hyperglycaemia and diabetic eye complications - a clinical and epidemiological study

Sammanfattning: Aim: To study the relationship between hyperglycaemia and the onset/progression of retinopathy, blindness/moderate visual impairment or death, as well as the impact of improved glycaemic control on retinopathy in patients with non-insulin-dependent diabetes mellitus (NIDDM). Methods: Between January 1990 and October 1995 a total of 3,220 diabetic patients were enrolled in a programme for control and screening for retinopathy. Of them 483 (15%) were below 30 years of age, and 2,737 (85%) 30 years or more at diagnosis and were considered representative of patients with insulin-dependent diabetes mellitus (IDDM) and NIDDM, respectively. Retinopathy was graded on fundus photographs using the Wisconsin scale. The time points for detection of blindness (visual acuity 0.1 or less)/ moderate visual impairment (visual acuity 0.2-0.4), progression of retinopathy or death were recorded. The average HbA1c for each patient was used to estimate long-term glycaemic control. Results: Prevalence, development and progression of retinopathy were significantly associated with poor glycaemic control in all diabetic patients. The presence of retinopathy at baseline predicted progression in the NIDDM group. A non-linear relationship was found in NIDDM between mean HbA1c and progression of retinopathy 3 levels or more with a threshold value of about 8.0 %. Patients who changed treatment from oral agents to insulin therapy had an increased risk for progression of retinopathy, which most likely was due to rapid lowering of blood glucose. Poor glycaemic control, severe retinopathy, and blindness were predictors of mortality. Conclusions: Poor glycaemic control and intensified treatment with insulin are risk factors for progression of retinopathy in patients with NIDDM.