Serum Osteopontin Is Associated with Cardio-Ankle Vascular Index-Defined Arterial Stiffness in Patients with Type 2 Diabetes Mellitus: A Cross-Sectional Study

Background: Peripheral arterial stiffness (PAS) is common in patients with type 2 diabetes mellitus (T2DM). Despite osteopontin (OPN) being linked to structural alterations in the vasculature, its specific association with the cardio-ankle vascular index (CAVI) as an indicator of PAS is still unclear. Methods: A total of 120 patients diagnosed with T2DM were enrolled in this cross-sectional study. Participants were stratified into the PAS group (CAVI ≥ 9.0) and the control group (CAVI < 9.0) based on the diagnostic criterion of CAVI ≥ 9.0. Circulating OPN concentrations were determined via a commercial enzyme-linked immunosorbent assay kit. Results: PAS was present in 72 (60.0%) participants. Relative to the control group, individuals with PAS were older (p < 0.001) and had higher fasting glucose (p = 0.015), glycated hemoglobin (p = 0.006), urine albumin-to-creatinine ratio (p = 0.007), and OPN (p < 0.001) levels, whereas their high-density lipoprotein cholesterol (HDL-C) concentrations were markedly lower (p = 0.021). Spearman’s rank correlation demonstrated a significant positive association between serum OPN concentrations and bilateral CAVI measurements (both p < 0.001). In multivariable Firth logistic regression, elevated serum OPN concentrations were independently predictive of PAS (adjusted odds ratio [aOR] = 1.035; 95% confidence interval [CI]: 1.012–1.066; p = 0.001), along with older age and lower HDL-C levels. These associations were consistent across conventional and penalized logistic regression analyses. Receiver operating characteristic curve analysis revealed that OPN alone achieved an area under the curve (AUC) of 0.748, whereas the model combining OPN, age, and HDL-C achieved an AUC of 0.831. Conclusions: Higher serum OPN levels were independently associated with PAS in patients with T2DM, particularly when combined with age and HDL-C.