The prognostic value of the CRP-albumin ratio for peripheral artery disease: A cross-sectional study from the National Health and Nutrition Examination Survey

The CRP-to-albumin ratio (CAR) has emerged as a composite inflammatory-nutritional biomarker with prognostic value in various cardiovascular conditions, yet its association with peripheral artery disease (PAD) in the general population remains underexplored. This study aimed to investigate the association between CAR and PAD in a nationally representative sample of US adults. We conducted a cross-sectional analysis of 6128 participants aged ≥40 years from the National Health and Nutrition Examination Survey (NHANES, 1999-2004). PAD was defined as an ankle-brachial index ≤0.90. Multivariable logistic regression models were used to evaluate the independent association between CAR and PAD, with progressive adjustment for demographic, behavioral, metabolic, and clinical covariates. A significant dose-response relationship was observed between CAR quartiles and PAD prevalence (P-trend < .001). After full adjustment, participants in the highest CAR quartile had more than twice the odds of PAD compared to the lowest quartile (odds ratios [OR]: 2.11, 95% confidence interval [CI]: 1.46-3.06). Subgroup analysis revealed a stronger association in individuals aged <65 years (P-interaction = .029). CAR is independently associated with PAD and may serve as an accessible biomarker for improving risk stratification and early detection, particularly in younger adults.