Comparison of Glyburide with Metformin in Treating Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

Background and Objective Controversy has surrounded the treatment of gestational diabetes mellitus (GDM) for a long time. Although the use of both glyburide and metformin are recommended as an alternate to insulin if dietary therapy fails in GDM patients, it remains unclear whether both drugs are equally safe and efficacious. Therefore, in this review we compared the efficacy and safety of glyburide with metformin in treating GDM. Methods A systematic review and meta-analysis of randomized controlled trials was conducted that compared the efficacy and safety of glyburide with metformin in GDM patients. Electronic databases were used to conduct the literature search for study identification along with a hand search of pertinent journals and conference proceedings. The effect measure used to present the results was risk ratio (RR) with 95 % confidence interval (CI). A fixed-effects model was used to pool the data if no significant heterogeneity was reported and a random-effects model was used in the case of significant heterogeneity being reported for an outcome. Results Three studies involving 508 patients met the inclusion criteria of this review. A significant increase in the risk of the composite outcome, i.e., macrosomia and large for gestational age (LGA) births (RR 1.94; 95 % CI 1.03-3.66, p = 0.04), was observed in the glyburide group, whereas a non-significant increase in the risk of neonatal hypoglycemia (RR 1.92; 95 % CI 0.31-12.02) was also noticed. Results remained statistically non-significant for preterm births (RR 0.65; 95 % CI 0.24-1.77), neonatal birth weight (mean difference (MD) 120.63 g; 95 % CI -62.08 to 303.33), and cesarean section (RR 0.86; 95 % CI 0.55-1.34). A significant decrease in fasting glucose levels (MD -2.40 mg/dL; 95 % CI -4.60 to -0.21; p = 0.03) was noticed in glyburide group while the difference was non-significant for postprandial glucose levels (MD -0.84 mg/dL; 95 % CI -4.03 to 2.35). Conclusion Metformin seems to be a superior choice to glyburide if oral antidiabetic drug therapy is to be initiated in GDM patients.