Comparison of glyburide and insulin for the management of gestational diabetics with markedly elevated oral glucose challenge test and fasting hyperglycemia

Objective: To compare the effectiveness of glyburide and insulin for the treatment of Gestational diabetes mellitus (GDM) in women who had OGCT >= 200 mg/dl and fasting hyperglycemia. Study design: A retrospective study was performed among a subset of women treated with glyburide or insulin for GDM from 1999 to 2002 with an OGCT >='200 mg/dl and pretreatment fasting plasma glucose >= 105 mg/dl. Exclusion criteria included pretreatment fasting >= 140 mg/dl, gestational age >= 34 weeks and multiple gestation. Maternal and neonatal outcomes were assessed. Statistical methods included bivariate and multivariable logistic regression analyses. Results: In 1999 to 2000, 78 women were treated with insulin; in 2001 to 2002, 44 of 69 (64%) received glyburide. There were no statistically significant differences between the two groups with regards to mean OGCT (230 +/- 25 vs 223 +/- 23 mg/dl, P = 0.07) and mean pretreatment fasting (120 +/- 10 vs 119 +/- 11 mg/dl, P = 0.45). Seven women (16%) failed glyburide. Women in the insulin group were younger (31.5 +/- 5.8 vs 35.2 +/- 4.7 years, P < 0.001) and had a higher mean BMI (32.4 +/- 6.4 vs 29.1 +/- 5.8 kg/m(2), P = 0.003) compared to glyburide group. There were no significant differences in birth weight (3524 +/- 548 vs 3420 +/- 786 g, P = 0.65), macrosomia (19 vs 23%, P = 0.65), pre-eclampsia (12 vs 11%, P = 0.98) or cesarean delivery (39 vs 46%, P = 0.45). Neonates in the glyburide group were diagnosed more frequently with hypoglycemia (34 vs 14%, P = 0.01). When controlled for confounders, macrosomia was found to be associated with glyburide treatment (OR 3.5, 95% CI 1.1 to 11.4). Conclusion: In women with GDM who had a markedly elevated OGCT and fasting hyperglycemia, glyburide achieved similar birth weights and delivery outcomes but was associated with an increased risk of macrosomia. The possible increased risk of neonatal hypoglycemia in the glyburide group warrants further investigation.