Predicting Progression from Gestational Diabetes to Impaired Glucose Tolerance Using Peridelivery Data: An Observational Study

Abstract

Objective: To develop a predictive model to identify persons with recent gestational diabetes (GDM) most likely to progress to impaired glucose tolerance postpartum. Study Design: We conducted an observational study among persons with GDM in their most recent pregnancy, defined by Carpenter-Coustan criteria. Participants were followed from delivery through 1-year postpartum. We used lasso regression with k-fold cross validation to develop a multivariable model to predict progression to impaired glucose tolerance, defined as HbA1c ≥ 5.7%, at 1 year postpartum. Predictive ability was assessed by the area under the curve (AUC), sensitivity, specificity, positive and negative predictive values. Results: Of 203 participants, 71(35%) had impaired glucose tolerance at 1 year postpartum. The final model had an AUC of 0.79 (95% CI 0.72, 0.85) and included eight indicators of weight, body mass index, family history of type 2 diabetes, GDM in a prior pregnancy, GDM diagnosis < 24 weeks’ gestation, and fasting and 2-hour plasma glucose at 2 days postpartum. A cut-point of ≥ 0.25 predicted probability had sensitivity 80% (95% CI 69, 89), specificity 58% (95% CI 49, 67), PPV 51% (95% CI 41, 61) and NPV 85% (95% CI 76, 91) to identify women with impaired glucose tolerance at 1 year postpartum. Conclusion: Our predictive model had reasonable ability to predict impaired glucose tolerance around delivery for persons with recent GDM.