245Comparison of methods for classifying heterogeneity in gestational diabetes (GDM) and association with outcomes. (2nd September 2021) - Gibbons, Kristen
Abstract: Background: Clinical experience suggests that diverse clinical subtypes exist within the broader diagnosis of GDM. Analysis from a single centre recently outlined heterogeneity in GDM with respect to insulin secretion and sensitivity, defining four GDM subtypes: 1) GDMsecr (<25 th centile HOMA-β (Hb) for non-GDM); 2) GDMsens (<25 th centile Matsuda Index for non-GDM); 3) GDMmixed (both GDMsecr and GDMsens ); 4) GDMND, no defect (neither GDMsecr and GDMsens ). Classification using these subtypes is associated with adverse outcomes. Methods: Following similar methodology, women with GDM were classified into four subtypes including comparison of Hb, insulinogenic index (II) and Stumvoll first-phase estimate (SV) for defining GDMsecr . Analyses compared neonatal outcomes with non-GDM women and between GDM groups using c 2 tests and regression analyses adjusted for multiple confounders including maternal age, BMI and HAPO study centre. Results: Hb, II and SV gave divergent results for GDMsecr, with only 19% concordance. In all analyses, GDMND (10% by Hb, 6% by II, 6% by SV) showed outcome frequencies similar to those of non-GDM women; groups 1-3 showed higher risks (p < 0.01 vs non GDM). These results persisted in the fully adjusted model (aOR generally >2.0). Conclusions: Different clinical subtypes in GDM are associated with differing risks of adverse outcome. Key messages: Determination of GDM subtype can assist in assessing GDM women at higher risk of adverse clinical outcome and help guide clinical practice.