Objective: We aimed to compare the discriminative power of prognostic models for early prediction of women at risk for the development of gestational diabetes mellitus (GDM) using four currently recommended diagnostic criteria based on the 75-g oral glucose tolerance test (OGTT). We also described the potential effect of application of the models into clinical practice.
Research design and methods: A prospective cross-sectional study of 2,772 pregnant women was conducted at a referral maternity center in Vietnam. GDM was determined by the American Diabetes Association (ADA), International Association of the Diabetes and Pregnancy Study Groups (IADPSG), Australasian Diabetes in Pregnancy Society (ADIPS), and World Health Organization (WHO) criteria. Prognostic models were developed using the Bayesian model averaging approach, and discriminative power was assessed by area under the curve. Different thresholds of predicted risk of developing GDM were applied to describe the clinical impact of the diagnostic criteria.
Results: The magnitude of GDM varied substantially by the diagnostic criteria: 5.9% (ADA), 20.4% (IADPSG), 20.8% (ADIPS), and 24.3% (WHO). The ADA prognostic model, consisting of age and BMI at booking, had the best discriminative power (area under the curve of 0.71) and the most favorable cost-effective ratio if implemented in clinical practice. Selective screening of women for GDM using the ADA model with a risk threshold of 3% gave 93% sensitivity for identification of women with GDM with a 27% reduction in the number of OGTTs required.
Conclusions: A simple prognostic model using age and BMI at booking could be used for selective screening of GDM in Vietnam and in other low- and middle-income settings.