98-OR: Gestational Glucose Intolerance without Gestational Diabetes Is a Risk Factor for Type 2 Diabetes

Abstract

Background: Women with gestational diabetes (GDM) have an increased risk of adverse perinatal outcomes and future type 2 diabetes (T2D). Gestational glucose intolerance (GGI, abnormal initial GDM screen) without GDM has been linked to adverse perinatal outcomes but is not a recognized T2D risk factor. We tested whether GGI without GDM is associated with incident T2D. Methods: Using clinical data from women seen at our US medical center for prenatal and primary care (1998-2018), we assessed risk of T2D (defined using validated laboratory and outpatient diagnoses) according to GGI/GDM status during pregnancy. We defined GGI as 1-hr glucose loading test (GLT) ≥ 140 mg/dl at ≥ 24 weeks gestation. We subcategorized GGI by 3-hr oral glucose tolerance test (OGTT) result. We used Cox proportional-hazard models with time-varying exposures/covariates to assess T2D risk after delivery, adjusting for age, race/ethnicity, parity, insurance type, marital status, BMI, and blood pressure. Women were followed from 1st delivery until diagnosed with T2D or censored at time of last primary care visit. Results: Among 13988 women, 17109 pregnancies had normal glucose tolerance (NGT, GLT < 140mg/dL). Among 3619 GGI pregnancies (GLT ≥ 140 mg/dl), 2076 had a normal OGTT, 699 had 1 abnormal OGTT value, and 844 had GDM (≥ 2 abnormal OGTT values). Over a median of 8.3 years of follow-up, 2.2% (N=304 women) developed T2D. In our primary comparison, women with GGI without GDM (16% of pregnancies) had increased T2D risk compared to women with NGT (HR 2.1 [1.5-2.9], p<0.001). Among women with GGI, T2D risk increased with the number of abnormal OGTT values (normal OGTT: HR 1.8; 1 abnormal OGTT value: HR 2.8; GDM: HR 11.7; p≤0.01 for all compared to NGT). Conclusions: Pregnant women with GGI without GDM have a two-fold increased risk of future T2D compared to those with NGT. Clinical data universally available during pregnancy identifies a large, previously unrecognized group of women who may benefit from T2D screening and prevention. Disclosure D. J. Selen: None. T. Thaweethai: None. S. Hsu: None. K. James: None. A. Kaimal: None. J. B. Meigs: Consultant; Self; Quest Diagnostics. C. E. Powe: None. Funding National Institutes of Health (2T32DK007028-46, K23DK113218); Robert Wood Johnson Foundation; Massachusetts General Hospital