Poster Presentation Australasian Diabetes in Pregnancy Society Annual Scientific Meeting 2019

An early pregnancy HbA1c ≥5.9% (41 mmol/mol) is not a valid biomarker for early or late gestational diabetes mellitus and does not predict adverse pregnancy outcomes in obese pregnant women (#72)

Jincy Immanuel 1 , David Simmons 1 , Gernot Desoye 2 , Juan M Adelantado 3 , Rosa Corcoy 3 , Roland Devlieger 4 , Sander Galjaard 4 , Annunziata Lapolla 5 , Maria G Dalfra 5 , Alessandra Bertolotto 6 , Jürgen Harreiter 7 , Ewa Wender-Ozegowska 8 , Agnieszka Zawiejska 8 , Alexandra Kautzky-Willer 7 , Fidelma P Dunne 9 , Peter Damm 10 , Elisabeth R Mathiesen 10 , Dorte M Jensen 11 , Lise Lotte T Andersen 12 , David J Hill 13 , Judith GM Jelsma 14 , Frank J Snoek 15 , Hubert Scharnagl 16 , Mireille NM Poppel 15
  1. School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
  2. Department of Obstetrics and Gynecology, Medizinische Universitaet Graz, Graz, Austria
  3. Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
  4. KU Leuven Department of Development and Regeneration: Pregnancy, Fetus and Neonate, Leuven, Belgium
  5. Universita Degli Studi di Padova, Padua, Italy
  6. Azienda Ospedaliero-Universitaria Pisana, Pisa, Italy
  7. Department of Medicine III, Division of Endocrinology, Gender Medicine Unit Medical University of Vienna , Vienna, Austria
  8. Division of Reproduction, Medical Faculty I, Poznan University of Medical Sciences, Poznan, Poland
  9. National University of Ireland, Galway, Ireland
  10. Center for Pregnant Women with Diabetes, Departments of Endocrinology and Obstetrics, Rigshospitalet, Copenhagen, Denmark
  11. Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
  12. Department of Gynecology and Obstetrics, Odense University Hospital, Odense, Denmark
  13. Recherche en Santé Lawson SA, St. Gallen, Switzerland
  14. Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Public and Occupational Health, Amsterdam Public Health research institute, Amsterdam, The Netherlands
  15. Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Medical Psychology, Amsterdam, The Netherlands
  16. Medical University of Graz, Clinical Inst Medical and Chemical Laboratory Diagnostics, Graz, Austria

Aims: To investigate the performance of early pregnancy HbA1c for predicting gestational diabetes mellitus (GDM) and adverse pregnancy outcomes.

Methods: This is a post hoc analysis of the Vitamin D And Lifestyle Intervention for GDM prevention trial conducted across 9 European countries (2012-2015). Pregnant women (BMI ≥ 29kg/m2) underwent a baseline HbA1c and oral glucose tolerance tests at <20 weeks, 24-28 weeks, and 35-37 weeks. GDM was defined by the International Association of Diabetes in Pregnancy Study Groups criteria. Women with GDM were treated according to local protocols.

Results: Among the 886 women tested, the prevalence of GDM was 26.3% before 20 weeks, with a further 8.5% at 24-28 weeks and 6.7% at 35-37 weeks. An early HbA1c ≥ 5.9% (41 mmol/mol) showed low sensitivity (9%) but reasonable specificity (96.9%) for GDM before 20 weeks, at 24-28 weeks (sensitivity of 1.3% and specificity of 96.9% after excluding early GDM) and throughout gestation (sensitivity of 7.1% and specificity of 97.1%). The areas under the curves at the 3 time points were 0.55 (0.51-0.59), 0.54 (0.47-0.61), and 0.55 (0.51-0.59) respectively. The ≥5.9% (41 mmol/mol) threshold was significantly associated with concurrent GDM before 20 weeks (adjusted OR 2.68 [1.39-5.15]) and throughout gestation (adjusted OR 2.67 [1.24-5.76]), but not adverse pregnancy outcomes. Using higher diagnostic criteria for GDM and fasting ≥6.1mmol/l in the first-trimester showed marginally better characteristics, but still with low sensitivity (<20%).

Conclusions: Early HbA1c was of limited use for predicting either GDM or adverse outcomes in overweight/obese pregnant women.