Metformin May Have Higher Failure Rate Than Glyburide for Gestational Diabetes
By Laurie Barclay, MD
Medscape Medical News
January 7, 2010 — The failure rate of metformin was approximately twice that of glyburide when used in the management of gestational diabetes mellitus (GDM), according to the results of a randomized trial reported in the January 2010 issue of Obstetrics Gynecology.
"The goal of this study was to compare blood glucose levels in patients taking metformin to blood glucose levels in patients taking glyburide for management of gestational diabetes," write Lisa E. Moore, MD, from the University of New Mexico School of Medicine in Albuquerque, and colleagues. "We hypothesized that metformin and glyburide would show equivalent efficacy in controlling blood glucose in a head-to-head comparison."
Women with GDM who did not achieve glycemic control with diet were randomly assigned to receive monotherapy with metformin (n = 75) or glyburide (n = 74). The main endpoint of the study was glycemic control, and secondary endpoints were rate of drug failure and neonatal and obstetric complications.
Mean fasting and 2-hour postprandial blood glucose levels were not statistically different between the 2 groups for those patients who achieved adequate glycemic control. However, insulin treatment was required for inadequate glycemic control in 26 patients in the metformin group (34.7%) vs 12 patients in the glyburide group (16.2%; P = .01).
"In this study, the failure rate of metformin was 2.1 times higher than the failure rate of glyburide when used in the management of gestational diabetes (95% confidence interval [CI], 1.2–3.9)," the study authors write.
Limitations of this study include small size and insufficient power to address secondary outcomes.
"This study addressed the use of glyburide and metformin as single-agent therapies," the study authors conclude. "Future studies are needed to determine whether there is a benefit in continuing these agents as adjuvant therapies in patients requiring insulin. In addition, the role of oral agents in patients with pregestational diabetes either as single agents or in combination with insulin needs to be addressed in future studies."
The study authors have disclosed no relevant financial relationships.
