Glycosylated haemoglobin levels in patients with diabetes mellitus.

Glycosylated haemoglobin A1 levels were measured in 186 patients with diabetes mellitus and 108 non-diabetic controls. Forty-nine diabetics were considered well controlled with at least three blood glucose levels below 10 mmol/L, while 50 diabetic patients were poorly controlled with at least three blood glucose levels above 15 mmol/L. Mean glycosylated haemoglobin A1 levels for the 108 normal controls was 7.45% +/- 0.73%, for the well controlled diabetics, 10.7% +/- 2%, and for poorly controlled diabetics, 15.0% +/- 2.5% of total haemoglobin. In patients with the onset of diabetes after the age of 40 years, there was a significant difference between the haemoglobin A1 levels in those with diabetic retinopathy and those without complications. There was a significant association between haemoglobin A1 levels and the duration of the disease in diabetics controlled with insulin.