Diagnostic Performance of Serum Xenopsin-Related Peptide-1 in Gestational Diabetes Mellitus: A Prospective Observational Study

Background/Objectives: Gestational diabetes mellitus (GDM) is one of the most common metabolic disorders during pregnancy and is associated with adverse maternal and neonatal outcomes. Xenopsin-Related Peptide-1 (XRP-1) has recently emerged as a potential regulator of glucose metabolism and insulin homeostasis. This study evaluated serum XRP-1 levels and assessed their diagnostic performance in women with GDM. Methods: In this prospective observational study, 120 pregnant women between 24 and 28 weeks of gestation were enrolled, including 60 women with GDM and 60 healthy controls. Serum XRP-1 concentrations were measured using an enzyme-linked immunosorbent assay (ELISA). Clinical, biochemical, and obstetric characteristics were compared between groups. Receiver operating characteristic (ROC) curve analysis and multivariable logistic regression were performed to evaluate the diagnostic performance and independent association of XRP-1 with GDM. Results: Serum XRP-1 levels were significantly higher in women with GDM than in healthy controls (3.45 ± 0.47 vs. 2.87 ± 0.46 ng/mL, p = 0.003). ROC analysis demonstrated moderate discriminatory performance for XRP-1 in identifying GDM (AUC = 0.658, 95% CI: 0.560–0.750), with an optimal cut-off value of 3.12 ng/mL, corresponding to 63.3% sensitivity and 61.7% specificity. Multivariable logistic regression demonstrated that serum XRP-1 remained independently associated with GDM after adjustment for maternal age, pre-pregnancy body mass index, gestational weight gain, and parity (adjusted OR 2.74, 95% CI 1.31–5.73; p = 0.007). HbA1c and C-reactive protein levels were also significantly higher in the GDM group. Conclusions: Serum XRP-1 concentrations were independently associated with GDM and demonstrated moderate diagnostic accuracy. Although XRP-1 cannot replace established diagnostic methods, it may represent a complementary biomarker for identifying gestational dysglycemia. Larger multicenter studies are required to validate its clinical utility.