Metabolic and immunologic effects of insulin lispro in gestational diabetes.

OBJECTIVE: To compare the immunologic response to insulin lispro with that to regular human insulin, thereby assuring its safety for use in women with gestational diabetes, and to verify that it is effective. RESEARCH DESIGN AND METHODS: We compared the metabolic and immunologic effects of insulin lispro and regular human insulin in 42 women >18 years of age diagnosed with gestational diabetes by oral glucose tolerance testing at 14-32 weeks of gestation. Patients were randomized to receive regular human insulin or insulin lispro before consuming a test meal. Serum insulin, blood glucose, and C-peptide concentrations were measured. Throughout the remainder of gestation, patients received premeal insulin lispro or regular human insulin combined with basal insulin and performed blood glucose self-monitoring before and after each meal. Insulin antibodies and HbA1c were determined at enrollment and 6 weeks later. In addition, 10 patients received continuous intravenous insulin (4 lispro, 6 regular human insulin) and dextrose infusions intrapartum to assess placental insulin transfer. RESULTS: Anti-insulin antibody levels were similar in the two groups. Insulin lispro was not detectable in the cord blood. During a meal test, areas under the curve for glucose, insulin, and C-peptide were significantly lower in the lispro group. Mean fasting and postprandial glucose concentrations and end point HbA1c were similar in the two groups. The lispro group demonstrated fewer hypoglycemic episodes (symptoms and blood glucose concentrations <55 mg/dl). No fetal or neonatal abnormalities were noted in either treatment group. CONCLUSIONS: Insulin lispro may be considered a treatment option for women with gestational diabetes.