Oral Presentation Australian Diabetes in Pregnancy Society 2018

Some International perspectives regarding changing the criteria for GDM (#17)

David Simmons 1
  1. Western Sydney University, Campbelltown, NSW, Australia

The IADPSG/WHO criteria were intended to move a plethora of diagnostic approaches to gestational diabetes (GDM) to a common pregnancy outcome based set of diagnostic criteria.  However, the adoption of these epidemiologically based criteria increases workload (costs) for the diabetes/antenatal services, with a reduction in birth and possibly longer term complications.  While many countries have moved to the new criteria (including Australia), others have either remained unchanged (eg New Zealand), moved to other criteria based upon the Hyperglycaemia And Pregnancy Outcomes (HAPO) risk thresholds (eg Canada, India) or manufactured other criteria (eg the UK).  There have now been several studies describing how the shift (with no other service changes) from old to the new criteria (Spain, Taiwan) were associated with a reduction in adverse pregnancy outcomes.  Other studies have shown that those untreated yet fulfilling IADPSG/WHO criteria have poor outcomes with both untreated fasting (eg UK odds ratio (95%CI) 5.1-5.5 mmol/l vs background: LGA-4.47(3.15-6.33), emergency caesarean section 1.66 (1.13-2.43), polyhydramnios (4.67 (1.83-11.89)) and untreated 1 hour (eg UK odds ratio (95%CI) ≥10.0 mmol/l vs background: LGA-2.58 (1.93-3.46), emergency caesarean section 1.49 (1.10-2.21), polyhydramnios (7.46 (4.06-13.72)) post glucose load results.  In Canada, where the criteria are at a higher HAPO threshold (odds ratio 2.0), the risk of adverse neonatal outcomes in those with untreated GDM by IADPSG/WHO criteria are 1.4(1.1-1.9) fold that of the background population.  Sweden has elected to address the uncertainty behind the costs and benefits of introducing the new IADPSG/WHO criteria, by rolling them out through a nationwide step wedge cluster randomised controlled trial (the CDC4G trial).    The new criteria clearly target a group of women at substantially increased risk of adverse pregnancy outcomes.  International experience can inform the Australian/New Zealand debate on which criteria will yield the best balance of costs and benefits.