Elevated Serum Amyloid P Component Identified as a Promising Biomarker for Gestational Diabetes Mellitus
核心洞察
A retrospective study of 111 pregnant women found serum amyloid P (SAP) levels were significantly elevated in gestational diabetes mellitus (搜索) (GDM) patients compared to those with normal glucose tolerance.
Serum SAP demonstrated strong predictive performance for GDM, with an area under the ROC curve of 0.929 (95% CI: 0.884–0.974) and a cutoff of 386.88 ng/mL yielding 75.5% sensitivity and 95.2% specificity.
In contrast, serum proteoglycan 4 (搜索) (PRG4) showed no significant difference between groups and lacked predictive value for GDM.
Elevated serum levels of serum amyloid P component (搜索) (SAP) are significantly and independently associated with gestational diabetes mellitus (搜索) (GDM), while serum proteoglycan 4 (搜索) (PRG4) shows no meaningful correlation with the condition, according to a retrospective observational study of 111 pregnant women conducted at Meizhou People's Hospital (搜索).
The study, which enrolled women undergoing routine prenatal examination and glucose tolerance testing between April 2024 and October 2025, compared serum SAP and PRG4 levels between 62 women with normal glucose tolerance (NGT) and 49 women diagnosed with GDM. GDM was diagnosed according to the International Association for Diabetes in Pregnancy Society Group (IADPSG) criteria using a 75 g oral glucose tolerance test performed between 24 and 28 weeks of gestation.
Divergent Biomarker Associations with GDM
The core finding was a highly significant elevation of serum SAP in the GDM group. The median serum SAP level in women with GDM was 437.66 (366.69, 543.72) ng/mL, compared with 232.22 (203.12, 295.86) ng/mL in the NGT group (Z=−7.744, p<0.001).
By contrast, serum PRG4 levels did not differ significantly between groups. The median PRG4 level was 2.09 (1.36, 2.78) ng/mL in the GDM group versus 1.61 (0.98, 2.55) ng/mL in the NGT group (Z=−1.595, p=0.111).
Predictive Performance
Receiver operating characteristic (ROC) curve analysis revealed that serum SAP had strong predictive value for GDM, with an area under the curve (AUC) of 0.929 (95% CI: 0.884–0.974, p<0.001). The optimal cutoff value, determined by the Youden index, was 386.88 ng/mL, yielding a sensitivity of 75.5% and a specificity of 95.2%.
In contrast, serum PRG4 demonstrated no predictive value, with an AUC of 0.588 (95% CI: 0.483–0.694, p=0.111). Its optimal cutoff of 1.36 ng/mL produced a sensitivity of 75.5% but a specificity of only 43.5%, confirming that PRG4 cannot effectively distinguish women with GDM from those with NGT.
Independent Risk Factors
Multivariate logistic regression analysis identified several independent correlates of GDM after adjusting for potential confounders. Advanced maternal age (≥30 years) was associated with a markedly elevated risk (OR=6.071, 95% CI: 1.248–29.536, p=0.025), as was a history of induced abortion (OR=5.063, 95% CI: 1.007–25.441, p=0.049). Serum SAP level ≥386.88 ng/mL remained independently associated with GDM (OR=3.292, 95% CI: 1.270–8.528, p=0.014). Notably, a history of adverse pregnancy showed an inverse association (OR=0.074, 95% CI: 0.007–0.842, p=0.036).
Mechanistic Context
SAP is a member of the pentraxin family and functions as an acute-phase reactant closely linked to inflammatory responses. The authors note that elevated SAP may contribute to GDM through multiple pathways, including amplification of systemic inflammatory signaling that induces peripheral insulin resistance, and interference with placental hormone secretion and nutrient transport. Specifically, elevated SAP is proposed to facilitate overactivated NF-κB inflammatory signaling and excess release of TNF-α and IL-6, which collectively impair peripheral insulin signal transduction and trigger insulin resistance—the core metabolic defect of GDM.
The findings are consistent with prior work, including a proteomics-based analysis by Ravnsborg et al that identified elevated SAP in early pregnancy among women with GDM, and a report by Can et al showing higher SAP levels in patients with metabolic syndrome.
Study Limitations
The authors acknowledge several important limitations. The study was a single-center, retrospective exploratory investigation with a moderate sample size (n=111), which may introduce selection bias and limit generalizability. Because of its cross-sectional and observational design, the study can only identify statistical associations rather than establish causal relationships between serum SAP levels and GDM pathogenesis.
Additional limitations include the absence of complete unified serum lipid profiles for all participants, single-time-point biomarker measurement at 24–28 weeks of gestation, lack of detailed lifestyle covariates and genetic susceptibility factors, and absence of postpartum metabolic follow-up data. The authors also caution that SAP, as an acute-phase reactant, may increase under diverse inflammatory stimuli, and therefore cannot yet be confirmed as a GDM-specific biomarker.
The researchers conclude that future multicenter, large-sample prospective investigations and mechanistic research are required to further validate these findings and facilitate the development of more effective strategies for the prevention and management of GDM.