Treatment of Type I Diabetes with a Combination of Glyburide and Insulin

Abstract

OBJECTIVE: To assess the ability of a combination of insulin and an oral hypoglycemic agent (glyburide) to improve the overall glycemic control in a population of patients with type I diabetes. DESIGN: Randomized, placebo-controlled, double-blind trial. SETTING: Community-based, university-affiliated, family medicine group. PATIENTS: Men and women between 18 and 68 years of age with type I diabetes. INTERVENTIONS: Subjects were observed and titrated on an insulin only regimen for 12 weeks (phase I). Subjects were then randomized to receive either placebo or glyburide 10 mg/d for an additional 12 weeks (phase II). MAIN OUTCOME MEASURES: Glucose measurements were taken at breakfast, lunch, supper, and bedtime. Each patient also was followed sequentially for serum lipids, glycosylated hemoglobin, (Hb A1c) and daily insulin utilization. RESULTS: Average fasting blood glucose (FBG) measurements were significantly lower in the glyburide-treated group during phase II (9.22 ± 0.55 mmol/L) compared with baseline (10.27 ± 0.93 mmol/L) and phase I (10.41 ± 0.55 mmol/L). A decrease in the average Hb A1c concentration in the glyburide group was evident by week 4 and was sustained for the duration of the study. The average daily insulin dose rose significantly in the glyburide but not the placebo group compared with baseline. Total cholesterol, triglycerides, and low-density lipoprotein cholesterol did not change significantly in either group over the course of the study. High-density lipoprotein cholesterol increased significantly over baseline in the glyburide group during phase II. Several patients experienced dramatic improvements in glycemic parameters after the addition of glyburide to their insulin regimens. CONCLUSIONS: Improvements were observed in the FBG and Hb A1c measurements of this heterogeneous population of patients with type I diabetes after the addition of glyburide to their insulin regimens. The study failed to find consistent trends in glycemic control when evaluating mean changes in FBG measurements.