NEW YORK (Reuters Health) - Women with gestational diabetes are more likely to maintain target glucose levels with glyburide than with metformin, a randomized trial has shown.
The researchers who conducted the trial had expected that both agents would be equally effective in these women. Not only was this not the case, but failure rates were high, and many women eventually required insulin.
Recent studies have shown that when gestational diabetes can't be controlled by diet and exercise, oral agents may perform as well as insulin in some patients, according to lead author Dr. Lisa E. Moore and her colleagues at the University of New Mexico in Albuquerque. In their study, women with gestational diabetes received monotherapy with either metformin (n = 75) or glyburide (n = 74).
Glyburide was started at 2.5 mg twice daily, increased as needed to a maximum of 20 mg/d. Metformin was started at 500 mg/d and could be raised up to 2 g/d.
The primary outcome was glycemic control, defined as a fasting blood glucose of 105 mg/dL or less and a 2-hour postprandial blood glucose of 120 mg/dL or less. In the glyburide arm, six patients failed to finish the trial, as did eight patients in the metformin arm. The intent-to-treat analysis is reported in the January issue of Obstetrics and Gynecology.
Twenty-six patients (35%) on metformin and 12 (16%) on glyburide did not meet glycemic goals and were switched to insulin therapy (p = 0.01, adjusted odds ratio 2.7).
There were no significant differences between groups in estimated gestational age at delivery, macrosomia, NICU admission, neonatal or maternal hypoglycemia, preeclampsia, or shoulder dystocia.
However, there were 11 nonelective cesarean deliveries in the metformin group versus two in the glyburide group (p = 0.02). On the other hand, birth weights were significantly higher in the glyburide group (3330 vs 3103 g, p = 0.02).
"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," Dr. Moore's team concludes.
