Diabetic retinopathy in Nigerians: relation to duration of diabetes, type of treatment and degree of control.

The results of a prospective study of the prevalence of diabetic retinopathy among Nigerian diabetics attending a Nigerian Teaching Hospital over a one and a half-year period are presented. Diabetics with mature cataracts whose fundi could not be visualised were excluded from the study. 15.1% of the 377 diabetic patients included in the study group had changes consistent with diabetic retinopathy. The prevalence was found to increase with increasing duration of disease, being 12.7%, 16.8% and 20.0% in patients with duration less than 5 years, between 5 and 10 years and greater than 10 years respectively. A considerably higher prevalence was also found in the insulin treated diabetics compared to the non insulin treated group (P less than 0.05). The degree of glycaemic control appeared to be poorer in the diabetics with retinopathy compared to those without, even though the differences between the mean fasting plasma glucose concentrations between the two groups did not reach statistical significance. Proteinuria was found to be significantly commoner in diabetics with retinopathy (P less than 0.025). It was concluded that diabetic retinopathy is on the increase among Nigerians and that efforts should be directed at evolving preventive measures and early identification of high risk patients.