Hemoglobin A1 and diabetic retinopathy.

The levels of the minor hemoglobin A1 components were measured in a consecutive series of 102 diabetic patients who were extensively studied for signs of diabetic retinopathy. We found a statistically significant relationship between metabolic control, as reflected by the hemoglobin A1 level, and the severity of diabetic retinopathy in patients with diabetes diagnosed before 30 years of age (P less than or equal to .001). We did not demonstrate a significant correlation between metabolic control and the severity of retinopathy in patients with diabetes diagnosed after the age of 30 years. We found significantly more severe retinopathy among patients with longer duration of the disease, in men, in whites, in diabetics diagnosted before 30 years of age who were treated with lower insulin doses, and in obses patients with the onset of diabetes after the age of 30 years.