2156-P: Early Insulin Resistance Is a Stronger Predictor of Early than Late Gestational Diabetes

Introduction and Objective: Early pregnancy insulin resistance (eIR) increases risk of gestational diabetes (GDM). We compared early (eGDM) and late GDM (lGDM) in their relationship with eIR. Methods: Pregnant women with GDM risk factors enrolled in a multicenter RCT had a 75g OGTT before 20w using IADPSG criteria, with fasting serum insulin measured. Repeat OGTT occurred at 24-28w if OGTT was normal and in 50% of those with eGDM. Homeostatic Model Assessment (HOMA)-IR (Glucose x Insulin)/22.5) values were log-transformed and standardized to a z score to estimate odds ratios (OR(95% CI)) per 1-SD increase in log-HOMA. Logistic binomial regression was used to adjust the OR of GDM for confounders. A non-linear association between HOMA-IR and GDM was assessed by adding a squared term for HOMA-IR. Area under the receiver operator curve (AUROC) with 95% CI was used for eGDM and lGDM prediction. Results: Among 1225 women (mean age 32±5y, BMI 29.6±7.8 kg/m2, OGTT gestation 15±2w, 43.3% European), mean HOMA-IR (1.44±1.86 for no-GDM) was 2.44±2.08 for eGDM and 1.58±1.85 for lGDM (p0.001). The OR for eGDM and lGDM were 2.09 (1.82-2.40) and 1.39 (1.17-1.65) per 1-SD increase in HOMA-IR respectively with adjusted OR 2.03(1.69-2.42) and 1.45 (1.15-1.82). The association was nonlinear for eGDM (p=0.002) but linear for lGDM (fig 1). The AUROC was significantly higher for eGDM than lGDM (0.71 (95% CI 0.68-0.74) vs 0.60(0.56-0.64)). Conclusion: Early pregnancy insulin resistance is a stronger predictor of eGDM than lGDM. Disclosure D. Simmons: Speaker's Bureau; Ended; Novo Nordisk. Other - Educational grant; Ended; Abbott Diabetes. Research Support; Current; Novo Nordisk. Consultant; Ended; Dexcom, Inc. A. Sweeting: None. J. Immanuel: None. M. Hivert: None. V.W. Wong: None. J. Harreiter: None. W.M. Hague: None. N. Pham: None. C. Nolan: None. N. Cheung: Other - honorarium for speakership; Ended; AstraZeneca. V. Mohan: None. A. Kautzky-Willer: None. M.J. Peek: None. E. Gianatti: None. A.A. Hardikar: None. M.V. Joglekar: None. H.E. Backman: None. Funding NHMRC (grants 1104231 and 2009326); Region Örebro Research Committee DnrOLL-970566, OLL-942177; Medical Scientific Fund of the Mayor of Vienna, project 15205; SouthWestern Sydney Local Health District Academic Unit grant 2016; Western Sydney University AinsworthTrust grant 2019