Hemoglobin A_1c Levels in Children and Adolescents with Diabetes Mellitus

Hemoglobin A_1c (HbA_1c) was measured as an indicator of glucose control in 180 children and adolescents with diabetes mellitus who received two daily injections of insulin as part of a highly structured treatment program. A total of 426 HbA_1c determinations was made in the group of 180 patients. HbA_1c values were elevated in most patients despite the aggressive treatment. The HbA_1c level was very elevated at diagnosis, fell to near normal after 60–90 days of insulin therapy, increased gradually, and reached a plateau after approximately 4 yr duration (at about twice the level in normal subjects) (mean ± SEM, 10.0 ± 0.2% and 5.34 ± 0.07%, respectively). Mean insulin dose (U/kg/24 h) paralleled both HbA_1c and duration of diabetes. The relationship between endogenous insulin secretion and glucose control was examined in those patients with diabetes for longer than 5 yr. Patients were separated into three groups based on HbA_1c levels: those with HbA_1c less than 9% (N = 22), between 9 and 11% (N = 26), and greater than 11% (N = 28). Serum C-peptide and glucose concentrations were measured 2 h after a standard breakfast in those patients in the “low” and “high” HbA_1c groups (mean HbA_1c values 8.2% and 12.7%, respectively). C-peptide was detectable in all patients and the mean C-peptide levels did not differ significantly in the two groups, although postprandial glucose concentrations were significantly lower in the “low” HbA_1c group (means ± SEM, 96 ± 11 and 211 ± 21 mg/dl, respectively; P < 0.001).