Introduction
Gestational diabetes mellitus (GDM), defined as impaired glucose
metabolism first identified in pregnancy, complicates an estimated
288,000 pregnancies in the United States annually.1,2Without intervention, an estimated 70% of women with GDM progress to
type 2 diabetes within 10 years of delivery.3 Women
with GDM are at higher risk for stroke, cardiovascular and liver disease
during their lifetime.4-7 Current guidelines recommend
that women with recent GDM receive an oral glucose tolerance test (OGTT)
at 4-12 weeks postpartum and annually thereafter.8,9However, postpartum OGTT completion is less than
50%.10-13 Recently, an OGTT at 2 days postpartum,
prior to women being discharged after delivery, was shown to have
comparable predictive ability as an OGTT at 4-12 weeks postpartum, with
superior completion rates.14 Despite this advance, the
sensitivity and positive predictive value of an OGTT at either 2 days or
4-12 weeks postpartum to predict progression to impaired glucose
tolerance post-partum remains at 50% or less. This leads to a missed
opportunity to identify individuals after delivery most likely to
develop type 2 diabetes over their life course.14
Predictive models have been used to develop clinical risk scores, such
as the FINDRISC Diabetes Risk Score, to identify non-pregnant persons at
high risk for progression to types 2 diabetes for follow-up and
intervention.15-18 These risk scores do not account
for glucose metabolism in pregnancy and therefore are not applicable to
women with recent GDM. In women with GDM, age, body mass index (BMI),
race/ ethnicity, family history of type 2 diabetes, and insulin
treatment in pregnancy are all correlated with the risk of progressing
to pre-diabetes and type 2 diabetes postpartum,1,19,20but have not been integrated into a clinically useful prediction model
to identify high risk women at delivery.
To fill this gap, we developed a predictive model using clinical data
available around the time of delivery to identify women with GDM in
their most recent pregnancy who are at high risk for progression to
impaired glucose tolerance by 1 year postpartum.