First trimester fasting plasma glucose screen in advanced maternal age women: a cost-effectiveness analysis

The prevalence of preexisting type 2 diabetes mellitus (T2DM) in the United States is on the rise. Women of advanced maternal age (AMA, ≥35 years) are more likely to have preexisting T2DM in pregnancy because glucose intolerance increases with age. Diabetes in pregnancy is associated with significant maternal and neonatal morbidity and mortality, and earlier treatment initiation improves pregnancy outcomes. However, maternal age is not currently recognized as an independent risk factor that warrants diabetes screening prior to the traditional screen at 24-28 weeks gestation.

To evaluate the cost-effectiveness of screening all AMA women with a first trimester fasting plasma glucose (FPG) test for earlier diagnosis and management of preexisting T2DM.

A decision-analytic model was created to compare pregnancy outcomes in AMA women who undergo a first trimester FPG test vs third trimester oral glucose tolerance test alone. Probabilities were obtained from the literature. Outcomes examined included preeclampsia, preterm delivery, macrosomia, shoulder dystocia, brachial plexus injury (BPI), intrauterine fetal demise (IUFD), cerebral palsy, and neonatal death. The cost, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio of the first trimester screening strategy were examined as well. Sensitivity analyses and a Monte Carlo simulation were performed to test the model's robustness.

In AMA women, screening for preexisting T2DM in the first trimester with an FPG test resulted in fewer cases of preeclampsia, preterm delivery, BPI, IUFD, cerebral palsy, and neonatal death compared to performing a third trimester oral glucose tolerance test alone, and is cost-effective. Monte Carlo analysis incorporating the distribution of all probabilities showed that first trimester FPG screening remained cost-effective as long as the incremental cost of initiating diabetes treatment in the first trimester was less than $150,000 and the cost of the FPG screen was less than $2700.

Compared to third trimester oral glucose tolerance test alone, performing a first trimester FPG screen in AMA women is cost-saving and more effective.