Objective: Fasting hyperglycemia is common in patients with insulin-dependent diabetes mellitus (IDDM) treated with twice-daily subcutaneous insulin regimens. We postulated that substituting human ultralente insulin for the presupper dose of intermediate-acting insulin would improve overnight glycemic control in children and adolescents with IDDM.
Research design and methods: This 6-mo double-blind crossover study compared a conventional insulin regimen, a mixture of human NPH and regular given before both breakfast and supper (NPH), with a novel twice-daily regimen in which human ultralente replaced NPH before the evening meal (ultralente). This study was comprised of 20 children and adolescents (mean age and duration of IDDM 11.3 +/- 2.9 and 2.4 +/- 1.3 yr, respectively) from the Youth Clinic of the Joslin Diabetes Center, all of whom regularly performed self-monitoring of blood glucose (SMBG) and had been treated exclusively with human insulin (mean daily dose 0.75 +/- 0.22 U/kg). Subjects performed SMBG on a prescribed schedule with a glucose meter with an electronic memory, and recorded results of blood glucose measurements, insulin dosages, and episodes of hypoglycemia. Monthly measurements were obtained for height, weight, and HbA1, and mean daily insulin dosages and average blood glucose level before breakfast, lunch, supper, bedtime snack, and between 0200 and 0300 were calculated. Nonfasting serum lipids were measured at entry, crossover, and the end of the study.
Results: After 3 mo, mean HbA, did not differ significantly (9.1 +/- 1.7 vs. 9.5 +/- 1.4%, NPH and ultralente, respectively). Mean fasting blood glucose was significantly lower on ultralente (9.6 +/- 1.9 vs. 10.3 +/- 2.2 mM, P less than 0.05, and blood glucose showed a similar trend (0.05 less than P less than 0.1) before lunch (8.9 +/- 1.7 vs. 9.8 +/- 2.6 mM. Mean blood glucose before bedtime snack was significantly lower (P less than 0.01) on NPH (8.4 +/- 1.9 vs. 10.0 +/- 2.1 mM) but did not differ significantly before supper or between 0200 and 0300. On the two regimens, growth and serum lipids were normal and similar, and no differences were observed in the incidence or severity of hypoglycemia.
Conclusions: Compared with a mixed dose of regular and NPH, a similar dose of a mixture of regular and human ultralente insulin before supper caused a modest reduction in fasting blood glucose levels but was associated with higher blood glucose levels before the bedtime snack. Overall glycemic control, reflected in HbA1 values, was not significantly improved.