Retrospective review of GCT cutoff value based on pre-pregnancy BMI class in patients with GDM

Area of Science:

• Obstetrics and Gynecology
• Endocrinology
• Public Health

Background:

• Gestational diabetes mellitus (GDM) is a significant pregnancy complication.
• Current screening protocols for GDM often involve a glucose challenge test (GCT).
• The optimal GCT cutoff value for GDM screening may vary based on pre-pregnancy body mass index (BMI).

Purpose of the Study:

• To determine the optimal glucose challenge test (GCT) cutoff value for screening gestational diabetes mellitus (GDM).
• To evaluate if pre-pregnancy BMI influences the optimal GCT cutoff value for GDM prediction.
• To establish a standardized GCT cutoff for GDM screening across diverse BMI categories.

Main Methods:

• Retrospective cohort analysis of singleton pregnancies (2004-2020) at a tertiary healthcare center.
• Utilized the first GCT value obtained between 20-32 weeks gestation.
• Employed receiver operator curve (ROC) analysis and Youden Index to identify optimal GCT cutoff values for each BMI category.

Main Results:

• A total of 23,550 patients were analyzed, with a GDM diagnosis rate of 7.1%.
• Optimal GCT cutoff values ranged from 130 mg/dL to 133 mg/dL across different BMI categories (normal, overweight, and obese classes I-III).
• Area Under the Curve (AUC) values, indicating predictive accuracy, ranged from 0.88 to 0.92 across BMI groups.

Conclusions:

• The study supports a universal GCT cutoff value of 130 mg/dL for GDM screening.
• This cutoff demonstrated high sensitivity (≥93%) across all pre-pregnancy BMI categories.
• A standardized GCT cutoff simplifies GDM screening protocols without compromising diagnostic accuracy.