Comparing Oral Glucose-Lowering Agents and Insulin in Gestational Diabetes
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Reviewed by Dat Tien Nguyen, B.A, ScM.
Translated by Nhi Phuong Quynh Le, B.A |
Posted on April 23rd, 2025
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Insulin has long been the standard therapy for controlling blood glucose in women with gestational diabetes. While oral agents like metformin and glyburide offer a more convenient alternative due to their ease of administration, the American Diabetes Association has advised against their use because of limited data on the long-term safety for offspring. To address this issue, the Australian National Health and Medical Research Council sponsored a study comparing the effectiveness of oral glucose-lowering agents with insulin for managing gestational diabetes.
The study was conducted in the Netherlands and included 820 pregnant women with an average age of 33.2 years who had difficulty achieving glycemic control. Gestational diabetes was diagnosed using either an oral glucose tolerance test or a daily glucose curve. At baseline, the participants had a fasting plasma glucose level of approximately 101 mg/dL and a two-hour post-challenge glucose level of 167 mg/dL following a 75-g glucose load. In this open-label trial, participants were randomly assigned to receive either insulin, administered according to local practice guidelines, or metformin as the initial treatment. Metformin was started at 500 mg per day and could be increased to 1000 mg three times daily if glycemic control was not attained. For those who did not achieve control on the highest dose of metformin, 2.5 mg of glyburide was added before each meal.
After delivery, researchers noted no significant differences between the two groups in terms of neonatal size, weight, APGAR scores, or other complications. However, the oral glucose-lowering treatment group experienced a higher incidence of hypoglycemia, likely due to glyburide's action in boosting pancreatic insulin secretion. Furthermore, the authors observed that up to 26% of patients receiving metformin and glyburide required additional insulin to achieve proper blood glucose control. The study had several limitations, including an open-label design that increases the risk of bias and limited generalizability because it was conducted solely in the Netherlands. Future research should address these limitations.
The study was conducted in the Netherlands and included 820 pregnant women with an average age of 33.2 years who had difficulty achieving glycemic control. Gestational diabetes was diagnosed using either an oral glucose tolerance test or a daily glucose curve. At baseline, the participants had a fasting plasma glucose level of approximately 101 mg/dL and a two-hour post-challenge glucose level of 167 mg/dL following a 75-g glucose load. In this open-label trial, participants were randomly assigned to receive either insulin, administered according to local practice guidelines, or metformin as the initial treatment. Metformin was started at 500 mg per day and could be increased to 1000 mg three times daily if glycemic control was not attained. For those who did not achieve control on the highest dose of metformin, 2.5 mg of glyburide was added before each meal.
After delivery, researchers noted no significant differences between the two groups in terms of neonatal size, weight, APGAR scores, or other complications. However, the oral glucose-lowering treatment group experienced a higher incidence of hypoglycemia, likely due to glyburide's action in boosting pancreatic insulin secretion. Furthermore, the authors observed that up to 26% of patients receiving metformin and glyburide required additional insulin to achieve proper blood glucose control. The study had several limitations, including an open-label design that increases the risk of bias and limited generalizability because it was conducted solely in the Netherlands. Future research should address these limitations.