Endocrine Abstracts

Background and aims: Gestational diabetes (GDM) is defined as glucose intolerance resulting in hyperglycaemia with onset or first recognition during pregnancy and has a prevalence of 1-28% worldwide. Treatment consists of lifestyle and dietary measures. If this proves insufficient, insulin therapy is initiated. Adequate identification of patients requiring insulin therapy can help decide which patients require more intensive follow-up. The three measurements of the OGTT can be combined rather than being assessed individually. The area under the curve of the OGTT (AUC OGTT) provides an estimate of the overall glucose excursion following a 75g glucose load, while the profile of the OGTT illustrates the change in blood glucose over the course of the two hours following the glucose load.

Methodology: This is a retrospective monocentric study that examined whether the AUC OGTT and/or the profile of the OGTT can predict whether insulin therapy needs to be initiated in patients with GDM. The medical records of all patients with singleton pregnancy and with an abnormal OGTT between 03/2020 to 09/2023 were reviewed. Exclusion criteria were pre-existing diabetes, use of medication that may interfere with glucose metabolism and multiple pregnancy.

Results: A total of 235 patients with GDM were studied. They were on average 32.8 years old (±5.2), had a prepregnancy BMI of 27.1 kg/m² (±5.8), and had mean glycaemia of 89 (±13), 172 (±28), and 158 (±25) mg/dl during the 75g OGTT at 0, 60, and 120 minutes, respectively. Patients who required insulin therapy were older, had a higher weight and BMI before pregnancy, had higher glycaemias during the OGTT with also a higher AUC OGTT. They were also more likely to have an OGTT profile characterized by impaired fasting glycaemia. Insulin therapy had to be initiated in all patients with impaired fasting glucose on all three OGTT points. The predictive model using the profile of the OGTT was superior to the predictive model using the AUC OGTT. Additionally, the former could also differentiate between modality of insulin therapy (basal, prandial and/or basal/prandial) unlike the latter. Factors such as BMI, fasting glycaemia, AUC OGTT and OGTT profile, HbA1c, fructosamine and total daily dose of insulin predict abnormal postpartum OGTT results.

Conclusion: Worldwide, the number of women with gestational diabetes is increasing. Risk stratification is necessary to identify those who need more intensive follow-up. The AUC OGTT is a predictor of whether insulin therapy has to be initiated during pregnancy. However, the profile of the OGTT, especially profiles where fasting glycemia is impaired, seems to be a more important predictor for insulin therapy during GDM pregnancy.