Assessment of neutrophil percentage to albumin ratio as a diagnostic biomarker for osteoarthritis: A cross-sectional study utilizing NHANES data

Osteoarthritis (OA) is a major global public health issue that significantly impairs patients' quality of life. The neutrophil percentage to albumin ratio (NPAR) has emerged as a promising inflammatory marker for the diagnosis and prognosis of various inflammatory conditions, yet its relationship with OA remains unexplored. This study aimed to examine the association between NPAR and OA and evaluate its diagnostic potential. Using cross-sectional data from the National Health and Nutrition Examination Survey (NHANES, 1999-2020), we analyzed 38,302 participants, including 2890 with OA. Weighted multivariate logistic regression, subgroup analyses, curve fitting, and inflection point analyses were employed, with C-reactive protein as a positive control. Diagnostic performance was assessed via receiver operating characteristic curve analysis. After adjusting for covariates, elevated NPAR was significantly associated with increased OA risk (odds ratio [OR] = 1.045; 95% confidence interval [CI]: 1.016-1.075; P = .0029). Subgroup analyses indicated significant associations in males (OR = 1.071; 95% CI: 1.024-1.121; P = .003), individuals aged 20 to 49 (OR = 1.057; 95% CI: 1.001-1.115; P = .045) and 60 to 69 (OR = 1.064; 95% CI: 1.003-1.130; P = .041), Mexican Americans (OR = 1.115; 95% CI: 1.016-1.223; P = .022), non-Hispanic whites (OR = 1.043; 95% CI: 1.009-1.079; P = .014), and moderate drinkers (OR = 1.117; 95% CI: 1.050-1.189; P < .001). Diagnostic evaluation revealed that NPAR had lower overall accuracy than C-reactive protein; however, among males, its diagnostic performance was comparable. In conclusion, NPAR is positively associated with OA risk and may offer supplementary diagnostic value, particularly in populations where C-reactive protein is less sensitive.