The association between normal 50-gram Glucose Challenge Test results and risk for cardio-metabolic morbidities

Objective
To address the association between 50-gram Glucose Challenge Test (GCT) results within the normal range of 120-139 mg/dL and the incidence of future endo-metabolic (EM) and cardio-vascular (CV) morbidities.
Study Design
This was a population-based retrospective cohort study including all pregnant women aged 17-55 who underwent GCT between the years 2005 and 2020 at the Central District of Clalit Health Services, the largest Health Maintenance Organization in Israel. GCT results were categorized as normal-low (< 120 mg/dL); intermediate (120-129 mg/dL); normal-high (130-139 mg/dL). EM morbidities were defined as pre-diabetes, type 2 diabetes mellitus or impaired lipid profile and CV morbidities as hypertensive disease, ischemic heart disease or vascular diseases. Cox proportional survival analysis models were used to calculate the Hazard Ratios for EM and CV morbidities among women with intermediate and normal-high versus normal-low GCT results. Both models adjusted for clinical and demographic characteristics.
Results
During the study period 77,568 women met the inclusion criteria, of them 53%, 12.3% and 10.3% had normal-low, intermediate, and normal-high GCT results, respectively. Mean follow-up periods were 6.07 and 6.73 years, for EM and CV morbidities, respectively. Intermediate and normal-high GCT results were significantly associated with increased risk for future EM morbidity, compared to normal-low results (Figure). This risk increased as the GCT result was higher, with adjusted HR=1.15 and 1.32 for intermediate and normal-high GCT results, respectively (P< 0.001) (Table). Among women < 35 years old, normal-high GCT results were associated with significant increased risk for future hypertensive disease (adjusted HR=1.23, 95% CI 1.001-1.511).
Conclusion
Women with GCT results ranging between 120-139 mg/dL are at increased risk for EM and CV morbidities compared to women with normal-low GCT results. Closer follow-up and early interventions in low-risk women with intermediate or normal-high GCT results may prevent EM disorders and hypertensive diseases later in life.