Association of retinopathy and glycosylated haemoglobin levels in diabetes mellitus.

One hundred and forty patients with diabetes mellitus were examined in the small mining town of Kalgoorlie, Western Australia. The primary object was to determine the incidence of retinopathy in the diabetic community. One hundred and thirty-eight sets of data were obtained. There were 69 males and 69 females. The diabetes was controlled with orally administered hypoglycaemic agents in 62 patients, in 58 patients with insulin, and in 18 by diet alone. Forty-six of the 138 volunteers (33%), were found to have retinopathy and this included eight of the 14 Aboriginals taking part in the survey. Glycosylated haemoglobin levels ranged from 8.1% to 18.8% (mean 11.7%; SD; 2.28%) of total haemoglobin concentration, and plasma glucose levels from 1.2 mmol/L to 27.3 mmol/L (mean, 9.5 mmol/L, SD, 5.06 mmol/L); there was a positive correlation between levels of glycosylated haemoglobin and plasma glucose (r = 0.63; P less than 0.001). Diabetics with retinopathy had a mean glycosylated haemoglobin level of 12.5% compared with 11.3% in those without this complication. Examination by treatment groups showed that patients with retinopathy whose disease was controlled with insulin had significantly higher levels of glycosylated haemoglobin compared with those without this complication (0.01 greater than P greater than 0.001). Patients whose disease was controlled with orally administered hypoglycaemic agents did not show this difference.