Objective: To compare the efficacy of metformin with glyburide for glycemic control in gestational diabetes.
Methods: Patients with gestational diabetes who did not achieve glycemic control on diet were randomly assigned to metformin (n=75) or glyburide (n=74) as single agents. The primary outcome was glycemic control. Secondary outcomes were drug failure rate and neonatal and obstetric complications.
Results: In the patients who achieved adequate glycemic control, the mean fasting and 2-hour postprandial blood glucose levels were not statistically different between the two groups. However, 26 patients in the metformin group (34.7%) and 12 patients in the glyburide group (16.2%) did not achieve adequate glycemic control and required insulin therapy (P=.01).
Conclusion: 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 1.2-3.9).
Clinical trial registration: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00965991.
Level of evidence: I.