Screening of postpartum diabetes in women with gestational diabetes: high-risk subgroups and areas for improvements-the STRONG observational study

Abstract

Aims: To assess the proportion of women with gestational diabetes (GDM) by performing postpartum Oral Glucose Tolerance Test (OGTT) and to identify GDM phenotypes at high-risk of postpartum dysglycemia (PPD).

Methods: Observational, retrospective, multicenter study involving consecutive GDM women. Recursive partitioning (RECPAM) analysis was used to identify distinct and homogeneous subgroups of women at different PPD risk.

Results: From a sample of 2,736 women, OGTT was performed in 941 (34.4%) women, of whom 217 (23.0%) developed PPD. Insulin-treated women having family history of diabetes represented the subgroup with the highest PPD risk (OR 5.57, 95% CI 3.60-8.63) compared to the reference class (women on diet with pre-pregnancy BMI < = 28.1 kg/m²). Insulin-treated women without family diabetes history and women on diet with pre-pregnancy BMI > 28.1 kg/m² showed a two-fold PPD risk. Previous GDM and socioeconomic status represent additional predictors. Fasting more than post-prandial glycemia plays a predictive role, with values of 81-87 mg/dl (4.5-4.8 mmol/l) (lower than the current diagnostic GDM threshold) being associated with PPD risk.

Conclusions: Increasing compliance to postpartum OGTT to prevent/delay PPD is a priority. Easily available characteristics identify subgroups of women more likely to benefit from preventive strategies. Fasting BG values during pregnancy lower than those usually considered deserve attention.

Keywords: Gestational diabetes; Obesity; Postpartum dysglycemia; Risk factors; Type 2 diabetes.

Fig. 1

Distribution by development and type of postpartum dysglycemia. GDM gestational diabetes mellitus, IFG impaired fasting glucose, IGT impaired glucose tolerance, T2DM type 2 diabetes

Fig. 2

Results of the RECPAM analysis: identification of subgroups at different risks of developing postpartum dysglycemia. The tree-growing algorithm modeled odds ratios (ORs) following a logistic regression model with age, education, occupation, ethnicity, previous GDM, pre-pregnancy BMI, family history of diabetes, first pregnancy, physical activity before pregnancy, smoke, treatment, total cholesterol, HDL, LDL, triglycerides, systolic blood pressure, diastolic blood pressure and composite of adverse neonatal outcomes as covariates. Splitting variables are shown between branches, whereas the condition sending patients to the left or right sibling is on the relative branch. Circles indicate subgroups of patients, squares indicate the final RECPAM classes. Numbers inside circles and squares represent the number of events (top) and the number of nonevents (bottom), respectively. An OR with the corresponding 95% CI (in parentheses) is shown for each class. Class 4, with the lowest risk of developing dysglycemia, is placed at the extreme right and is the reference category (OR = 1)

Fig. 3

Additional exploratory RECPAM analyses on the subgroups of women with available data on FBG at first trimester and OGTT 24–28 weeks. a Identification of subgroups at different risks of developing postpartum dysglycemia including FBG (mg/dl) at first trimester of pregnancy as additional covariate (N = 423). b Identification of subgroups at different risks of developing postpartum dysglycemia including OGTT at 24–28 weeks (mg/dl) as additional covariate (N = 513)