Correlates of Insulin Selection as a First-Line Pharmacological Treatment for Gestational Diabetes

Objective The aim of this study was to investigate prenatal factors associated with insulin prescription as a first-line pharmacotherapy for gestational diabetes mellitus (GDM; compared with oral antidiabetic medication) after failed medical nutrition therapy. Study Design This is a retrospective cohort study of 437 women with a singleton pregnancy and diagnosis of A2GDM (GDM requiring pharmacotherapy), delivering in a university hospital between 2015 and 2019. Maternal sociodemographic and clinical characteristics, as well as GDM-related factors, including provider type that manages GDM, were compared between women who received insulin versus oral antidiabetic medication (metformin or glyburide) as the first-line pharmacotherapy using univariable and multivariable analyses. Results In univariable analysis, maternal age, race and ethnicity, insurance, chronic hypertension, gestational age at GDM diagnosis, glucose level after 50-g glucose loading test, and provider type were associated with insulin prescription. In multivariable analysis, after adjusting for sociodemographic and clinical maternal factors, GDM characteristics and provider type, Hispanic ethnicity (0.26, 95% confidence interval [CI]: 0.09-0.73), and lack of insurance (0.34, 95% CI: 0.13-0.89) remained associated with lower odds of insulin prescription, whereas endocrinology management of GDM (compared with obstetrics and gynecology [OBGYN]) (8.07, 95% CI: 3.27-19.90) remained associated with higher odds of insulin prescription. Conclusion Women of Hispanic ethnicity and women with no insurance were less likely to receive insulin and more likely to receive oral antidiabetic medication for GDM pharmacotherapy, while management by endocrinology was associated with higher odds of insulin prescription. This finding deserves more investigation to understand if differences are due to patient choice or a health disparity in the choice of pharmacologic agent for A2GDM. Key Points Insulin is recommended as a first-line pharmacotherapy for gestational diabetes. Women of Hispanic ethnicity were less likely to receive insulin as first line. Lack of insurance was also associated with lower odds of insulin prescription.