Trefoil Factor 3 as a Biomarker for Peripheral Artery Disease

Background: While trefoil factor 3 (TFF3) has been linked to cardiovascular disease, its role in peripheral artery disease (PAD) remains largely unexplored. In this prospective study, we assessed three pre-selected circulating biomarkers and found that TFF3 demonstrated the strongest association with the presence of PAD. Building on this finding, we integrated plasma TFF3 concentrations with clinical characteristics to construct predictive models aimed at identifying individuals with PAD and estimating their risk of major adverse limb events (MALE) over a two-year follow-up period. Methods: A total of 476 individuals were prospectively recruited, including 312 patients with PAD and 164 controls without PAD. At study entry, circulating concentrations of TFF3, oncostatin M (OSM), and brain-derived neurotrophic factor (BDNF) were quantified, and all participants were subsequently monitored for a two-year period. The primary endpoint was the occurrence of MALE within two years, comprising acute limb ischemia, major amputation, or lower extremity revascularization by either open surgical or endovascular approaches. PAD diagnosis served as the secondary outcome and was established by an ankle–brachial index (ABI) ≤ 0.9 or toe–brachial index (TBI) ≤ 0.67 in the presence of reduced or absent pedal pulses. For predictive model development, the cohort was randomly divided into training (70%) and testing (30%) sets. A random forest algorithm incorporating clinical variables and plasma TFF3 levels was developed and optimized using 10-fold cross-validation. Model discrimination was quantified using the area under the receiver operating characteristic curve (AUROC). For prognostic evaluation, patients were classified into low- and high-risk groups based on the optimal ROC-derived probability threshold of 0.60, and MALE-free survival between groups was assessed using Cox proportional hazards regression. Results: Among the three candidate biomarkers evaluated, only TFF3 demonstrated a significant association with PAD. Patients with PAD exhibited higher circulating TFF3 concentrations than those without PAD (7.27 ± 3.36 vs. 5.89 ± 2.67 pg/mL; p < 0.001), whereas OSM and BDNF showed no significant differences between groups. Over the two-year follow-up period, MALE occurred in 28 patients (9%). Predictive models combining plasma TFF3 measurements with clinical variables achieved strong performance for both PAD detection and 2-year MALE risk estimation, yielding AUROCs of 0.79 and 0.85, respectively. Furthermore, patients classified as high risk by the model experienced a significantly increased hazard of MALE during follow-up (HR 1.12, 95% CI 1.10–1.19; p = 0.003). Variable importance analysis revealed that TFF3 was the most influential predictor of MALE, followed by age and smoking history. Conclusions: Combining plasma TFF3 levels with readily available clinical characteristics enabled the development of a predictive model with good discriminatory ability for both PAD diagnosis and estimation of 2-year MALE risk. Such an approach may enhance risk stratification by identifying patients at elevated risk earlier in their disease course, thereby informing decisions related to vascular testing, referral for specialist evaluation, and implementation of targeted treatment strategies.