Estimated Treatment Effects of Tight Glycaemic Targets in Mild Gestational Diabetes Mellitus: A Multiple Cut-Off Regression Discontinuity Study Design

Abstract

Background: We investigated the treatment effects of tight glycaemic targets in a population universally screened according to the International Association of Diabetes and Pregnant Study Groups (IADPSG)/World Health Organisation (WHO) gestational diabetes mellitus (GDM) guidelines. As yet there, have been no randomized control trials evaluating the effectiveness of treatment of mild GDM diagnosed under the IADPSG/WHO diagnostic thresholds. We hypothesize that tight glycaemic control in pregnant women diagnosed with GDM will result in similar clinical outcomes to women just below the diagnostic thresholds. Methods: A multiple cut-off regression discontinuity study design in a retrospective observational cohort undergoing oral glucose tolerance tests (OGTT) (n = 1178). Treatment targets for women with GDM were: fasting capillary blood glucose (CBG) of ≤5.0 mmol/L and the 2-h post-prandial CBG of ≤6.7 mmol/L. Regression discontinuity study designs estimate treatment effects by comparing outcomes between a treated group to a counterfactual group just below the diagnostic thresholds with the assumption that covariates are similar. The counterfactual group was selected based on a composite score based on OGTT plasma glucose categories. Results: Women treated for GDM had lower rates of newborns large for gestational age (LGA), 4.6% versus those just below diagnostic thresholds 12.6%, relative risk 0.37 (95% CI, 0.16–0.85); and reduced caesarean section rates, 32.2% versus 43.0%, relative risk 0.75 (95% CI, 0.56–1.01). This was at the expense of increases in induced deliveries, 61.8% versus 39.3%, relative risk 1.57 (95% CI, 1.18–1.9); notations of neonatal hypoglycaemia, 15.8% versus 5.9%, relative risk 2.66 (95% CI, 1.23–5.73); and high insulin usage 61.1%. The subgroup analysis suggested that treatment of women with GDM with BMI ≥30 kg/m2 drove the reduction in caesarean section rates: 32.9% versus 55.9%, relative risk 0.59 (95%CI, 0.4–0.87). Linear regression interaction term effects between non-GDM and treated GDM were significant for LGA newborns (p = 0.001) and caesarean sections (p = 0.015). Conclusions: Tight glycaemic targets reduced rates of LGA newborns and caesarean sections compared to a counterfactual group just below the diagnostic thresholds albeit at the expense of increased rates of neonatal hypoglycaemia, induced deliveries, and high insulin usage.

Association between gestational abnormal glucose tolerance and maternal‐fetal outcomes

“…34 Song et al found that women treated for GDM by using tight glycemic targets had significant lower rates of newborn LGA and cesarean section. 35 A systematic review and meta-analysis of randomized trials for the United States Preventive Services Task Force demonstrated that appropriate management of gestational diabetes-including nutritional therapy, self-blood glucose monitoring, and administration of insulin if target blood glucose concentrations are not met-resulted in less preeclampsia, shoulder dystocia, and macrosomia. 36 Two previous studies have demonstrated that diet and insulin treatment of women with abnormal GCT results decreased adverse maternal and perinatal outcomes, including neonatal birth weight and cesarean deliveries.…”

“…Landon et al demonstrated that women diagnosed with GDM and treated with education, diet, and insulin had significantly lower rates of macrosomia and preeclampsia, relative to the control group 34 . Song et al found that women treated for GDM by using tight glycemic targets had significant lower rates of newborn LGA and cesarean section 35 . A systematic review and meta‐analysis of randomized trials for the United States Preventive Services Task Force demonstrated that appropriate management of gestational diabetes—including nutritional therapy, self‐blood glucose monitoring, and administration of insulin if target blood glucose concentrations are not met—resulted in less preeclampsia, shoulder dystocia, and macrosomia 36 .…”

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

“…Analysis of overlap of glycaemic data by combining fasting and postprandial blood glucose levels was not found to be useful in creating models for different glycaemic thresholds in our group of patients. We acknowledge however, that application of statistical data can be useful in determining the effect of treatment in observational studies and has been used to assess outcomes related to tight glycaemic control in GDM [295]. Future studies should aim to capitalise on statistical models for interpretation of glycaemic data.…”

“…Achievability of set goals is of immense importance in sustaining the required dietary and lifestyle amendments mandated by a diagnosis of gestational diabetes. In fact, in their study of tight glycaemic targets, Song et al have included women's preferences in their protocol for therapy intensification [295].…”

Impact of Changes to Procedures on the Evaluation of the Effectiveness of Forms of Professional Activation in Poland

“…It began to be used increasingly in socio-economic analysis from the late 1990s onwards. Since then, there have been many articles in the fields of education, the labour market, forensics, environmental protection, and health care, on the economic impact of regulatory change (Lee and Munk 2008;Lee and Lemieux 2010;Dong et al 2019;Lotsu et al 2019;Wang et al 2019Wang et al , 2021Ogunmodede et al 2020;Song et al 2020;Zhao et al 2021).…”