C-peptide levels during oral glucose tolerance test may be a useful biomarker for early detection of gestational diabetes mellitus

1. 30- and 60-minute C-peptide levels during an oral glucose tolerance test (OGTT) at 16–18 weeks gestation were significantly elevated in women who later developed GDM, suggesting it may be a useful early biomarker for risk stratification.

Evidence Rating Level: 2 (Good)

This prospective longitudinal cohort study investigated whether pancreatic beta-cell secretory products (proinsulin, insulin, C-peptide) measured at 16–18 weeks gestation could serve as early biomarkers to diagnose and risk-stratify gestational diabetes mellitus (GDM) in high-risk pregnant women. Eighty-three women with at least one GDM risk factor underwent a 75g OGTT at 16–18 and 24–28 weeks; 66 were analyzed after exclusions. The study, limited by a small sample size due to the COVID-19 pandemic, found that early concentrations of total proinsulin, intact proinsulin, and insulin were not significantly different between women who remained normoglycemic and those who progressed to GDM. However, C-peptide levels at 30 and 60 minutes post-glucose load showed significant discriminatory power (AUC 0.661, p=0.041 and AUC 0.744, p=0.003, respectively). The authors conclude that while proinsulin was not a useful early marker, C-peptide shows promise for early GDM identification in high-risk women, though these findings require validation in a larger cohort.

Click here to read the study in BMJ Open

Image: PD

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