The relationship between fibrinogen-to-albumin ratio and peripheral arterial disease: A cross-sectional study

Early detection of peripheral arterial disease (PAD) is challenging due to its frequently asymptomatic nature, underscoring the need for accessible biomarkers to enhance risk stratification. This study aimed to investigate the relationship between the fibrinogen-to-albumin ratio (FAR), a marker indicative of both inflammatory and anti-inflammatory states, and the prevalence of PAD. Additionally, we assessed its diagnostic performance in comparison with established inflammatory indices. This cross-sectional analysis included 4234 participants from the National Health and Nutrition Examination Survey conducted between 1999 and 2002. PAD was defined as an ankle-brachial index of <0.9. We examined the relationship between FAR and PAD using multiple logistic regression, restricted cubic splines, and subgroup analyses. The predictive performance of FAR was evaluated using the area under the receiver operating characteristic curve (AUC) and compared with that of other inflammatory indices. After adjusting for covariates, a significant positive correlation was found between FAR and PAD prevalence (odds ratio, 1.01; 95% confidence interval, 1.00-1.02; P = .003). A clear dose-response relationship was observed, with a strong trend (P for trend < .05) across the FAR quartiles. Restricted cubic spline analysis confirmed a linear association between FAR and the risk of PAD (P for overall < .001; P for nonlinear = .208). The association remained robust across various subgroups, particularly among former smokers, individuals without renal impairment, and those in partnered relationships. Receiver operating characteristic analysis revealed that FAR achieved an AUC of 0.695 (95% confidence interval, 0.663-0.726), with an optimal cutoff of 8.818% (sensitivity, 67.7%; specificity, 64.2%), significantly surpassing the AUCs of the neutrophil-to-lymphocyte ratio (0.561; P < .001), C-reactive protein-to-albumin ratio (0.558; P < .001), platelet-to-lymphocyte ratio (0.521; P < .001), and systemic immune-inflammation index (0.534; P < .001). FAR is independently associated with PAD and demonstrates superior discriminatory performance over conventional inflammatory markers. These findings suggest that FAR may serve as a cost-effective screening tool for identifying high-risk individuals, enabling timely vascular assessment in primary care settings.