Comment on Nachum et al. Glyburide Versus Metformin and Their Combination for the Treatment of Gestational Diabetes Mellitus: A Randomized Controlled Study. Diabetes Care 2017;40:332–337

Given the increasing popularity of oral agents, we commend Nachum et al. (1) on their randomized controlled trial examining metformin or glyburide as a first-line agent to treat gestational diabetes mellitus (GDM) and adding or switching to the alternate agent for adverse events or failures. However, we question whether the study design and conclusions can be generalized to many GDM populations. First, a GDM diagnosis was made at <24 weeks in 27 of 104 patients, suggesting impaired glucose tolerance predating the pregnancy in ∼25%. An early GDM diagnosis increased the risk of failing glyburide by about eightfold in our series (2). A recent cohort also demonstrated that pregnancies with GDM diagnosed …