Predictors of glyburide failure in the treatment of gestational diabetes

OBJECTIVE: Our objective was to identify among women with gestational diabetes mellitus (GDM) the patient characteristics that predict treatment failure with glyburicle. METHODS: Historical cohort of 95 GDM women offered glyburide after dietary failure with defined entry criteria. RESULTS: From November 2000 to May 2005, 118 women had 124 pregnancies and were offered glyburide therapy by the 2 codirectors of our Diabetes Clinic. All but 2 women elected glyburide, and 27 pregnancies were excluded due to criteria defined a priori to the study. A cohort of 95 women with 95 pregnancies were included for analysis. Nineteen percent failed glyburide. Significant predictors of failure were maternal age (34 years compared with 29 years, P =.001), earlier diagnosis of GDM (23 weeks compared with 28 weeks, P =.002), higher gravidity (P =.01) and parity (P =.03), and a higher mean fasting blood glucose (112 compared with 100 mg/dL; P =.045) compared with those successfully treated. After adjustment in the multivariable logistic regression analysis, GDM women diagnosed at a gestational age less than 25 weeks were 8.3 times more likely to fail glyburide compared with those diagnosed after 25 weeks. Maternal and fetal outcomes were favorable with a cesarean delivery rate of 25% and macrosomia rate of 7%. CONCLUSION: Glyburide was more likely to fail in women diagnosed earlier in pregnancy, of older age and multiparity, and with higher fasting glucoses, suggesting that earlier glucose intolerance and a reduced capacity to respond to an insulin secretagogue may distinguish this group. The time for glyburide as an alternative treatment has come; however, it should be prescribed after careful consideration of these patient characteristics to minimize the likelihood of failure.