Prevalence and predictors of postpartum glucose intolerance in Italian women with gestational diabetes mellitus

Abstract Aims To determine the prevalence of both prediabetes and type 2 diabetes mellitus (T2DM) by postpartum oral glucose tolerance test (ppOGTT) in Italian women diagnosed with gestational diabetes mellitus (GDM), and identify antepartum predictors of glucose intolerance. Methods Retrospective study of 454 Caucasian women that underwent a 75 g OGTT between 6 and 12 weeks postpartum in Calabria (Southern Italy) between 2004 and 2012. Prediabetes and T2DM were diagnosed according to the American Diabetes Association (ADA) criteria. Data were examined by univariate analysis and multiple regression analysis. Results 290 women (63.9%) were normal, 146 (32.1%) had prediabetes (85 impaired fasting glycemia; 61 impaired glucose tolerance), and 18 (4.0%) had T2DM. Of the continuous variables, pre-pregnancy body mass index (BMI), age at pregnancy, fasting plasma glucose (FPG) at gravid OGTT, and week at diagnosis of GDM were associated with prediabetes and T2DM, whereas the parity was associated with T2DM only. For categorical traits, pre-pregnancy BMI ≥25 and previous diagnosis of polycystic ovary syndrome (PCOS) emerged as the strongest predictors of prediabetes whereas the strongest predictors of T2DM were FPG ≥100 mg/dl (5.6 mmol/l) at GDM diagnosis and pre-pregnancy BMI ≥25. Moreover, FPG at GDM screening was a good predictor of T2DM after receiver-operating-characteristic analysis. Conclusions Our findings confirm the high prevalence of glucose intolerance in the early postpartum period in women with previous GDM. PCOS emerges as a new strong antepartum predictor of prediabetes.