The Utility of Lower Glycemic Targets for Treating Gestational Diabetes: A Retrospective Study

Abstract

Objective In vivo study of glucose homeostasis in pregnancy suggests normal glucose levels are lower than current glycemic targets used in gestational diabetes. After the HAPO study results, our institution began using glycemic targets of fasting 85 mg/dL and 2-hour postprandial of 110 mg/dL. We reviewed our results. Methods A retrospective cohort of GDM patients that delivered at KUMC from January 2007 to May 2017 was reviewed. All patients were diagnosed with the 2-step Carpenter-Coustan thresholds. High targets were compared with low targets. The primary outcome investigated was birthweight > 90% (large for gestational age, LGA). Results 604 patients were studied, and 34% were treated with low glycemic targets. Our unadjusted results showed that the low-target group had a lower incidence of LGA infants (24.0 vs. 31.8%), higher incidence of neonatal hypoglycemia (20.7 vs. 11.6%), and inductions (39.4 vs. 20.5%). After adjustment for demographic variables, only a higher risk of inductions remained (aOR 2.54 (1.44, 4.49)). Conclusion Lower glycemic targets did not produce large reductions in fetal overgrowth, but they were associated with a higher rate of inductions. As there were no observed differences in maternal or neonatal outcomes otherwise, aiming for lower glycemic targets in GDM is likely not cost-effective.

Single site pilot clinical investigation of a novel app-assisted self-management programme for gestational diabetes

“…Two published studies have compared the effect of higher treatment targets with lower treatment targets. The first, a retrospective cohort by Hagen et al, examined the effect of introduction of tighter treatment targets in their own institution by comparing this group with a historical cohort where higher targets were set [290].…”

“…However, this has not been upheld by the majority of studies interrogating this hypothesis. In fact, tighter treatment targets have been found to be associated with increased rates of intervention and induction of labour suggesting that lower glycaemic thresholds are not cost effective [289,290].…”

“…Increased insulin usage as a consequence of tighter targets might explain the higher rates of induction among services adopting these more stringent glycaemic thresholds. Selective application of lower targets may only be beneficial for GDM affected pregnancies where a third trimester fetal ultrasound scan suggests an increased risk for macrosomia [288,290,291]. Tight treatment targets have variously been defined as fasting capillary blood glucose levels < 4.7 mmol/l and < 5.0 mmol/l with 2-hour postprandial capillary blood glucose levels of 6.1 mmol/l and 6.7 mmol/l [289,290].…”

“…Selective application of lower targets may only be beneficial for GDM affected pregnancies where a third trimester fetal ultrasound scan suggests an increased risk for macrosomia [288,290,291]. Tight treatment targets have variously been defined as fasting capillary blood glucose levels < 4.7 mmol/l and < 5.0 mmol/l with 2-hour postprandial capillary blood glucose levels of 6.1 mmol/l and 6.7 mmol/l [289,290]. Interestingly, a 1-hour postprandial level of 7.8mmol/l appears to be consistent across studies [292].…”