"Changing Patterns in Medication Prescription for Gestational Diabetes During a Time of Guideline Change in the USA: A Cross-sectional Study".

OBJECTIVE To define patterns of prescription and factors associated with choice of pharmacotherapy for gestational diabetes mellitus (GDM), namely metformin, glyburide, and insulin, during a time period of evolving professional guidelines. DESING Cross-sectional study. SETTING U.S. commercial insurance beneficiaries from Market-Scan (late 2015 to 2018) STUDY DESIGN: We included women with GDM, singleton gestations, 15-51 years of age on pharmacotherapy. The exposure was pharmacy claims for metformin, glyburide, and insulin. MAIN OUTCOMES Pharmacotherapy for GDM with either oral agent, metformin or glyburide, compared to insulin as the reference, and secondarily, consequent treatment modification (addition and/or change) to metformin, glyburide, or insulin. RESULTS Among 37,762 women with GDM, we analyzed data from 10,407 (28%) with pharmacotherapy, 21% with metformin (n=2,147), 48% glyburide (n=4,984), and 31% insulin (n=3,276). From late 2015 to 2018, metformin use increased from 17% to 29%, as did insulin use from 26% to 44%, while glyburide use decreased from 58% to 27%. By 2018, insulin was the most common pharmacotherapy for GDM; and metformin was more likely to be prescribed by 9% compared to late 2015-2016, while glyburide was less likely by 45%. Treatment modification occurred in 20% of women prescribed metformin compared to 2% with insulin, and 8% with glyburide. CONCLUSIONS Insulin followed by metformin has replaced glyburide as the most common pharmacotherapy for GDM among a privately insured U.S. population during a time period of evolving professional guidelines. Further evaluation of the relative effectiveness and safety of metformin compared with insulin is needed.