A new analysis published in RMD Open reports that the neutrophil percentage to albumin ratio (NPAR) is significantly associated with increased osteoarthritis risk, with diagnostic performance in men comparable to that of C-reactive protein (CRP). The findings highlight the growing relevance of inflammatory composite markers in understanding musculoskeletal disease burden.
NPAR combines two widely available laboratory parameters: neutrophil percentage, a sensitive indicator of systemic inflammation, and serum albumin, a key protein involved in maintaining physiologic homeostasis and commonly used as a marker of nutritional and inflammatory status. Previous studies have linked NPAR to outcomes in conditions such as acute kidney injury, septic shock, and various malignancies, underscoring its value as a simple and cost-effective measure of inflammatory stress.
The study examined data from 38,302 participants in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2020, including 2,890 individuals with osteoarthritis. After adjusting for demographic and clinical covariates, higher NPAR values were significantly associated with increased osteoarthritis risk. Subgroup analyses showed particularly strong associations among men, adults aged 20–49 years and 60–69 years, non Hispanic whites, and moderate alcohol consumers.
Receiver operating characteristic curve analysis showed that while NPAR had lower overall diagnostic accuracy than CRP in the general population, its performance in men was comparable to CRP. This suggests that NPAR may offer additive diagnostic value in subgroups where CRP is less sensitive.
NPAR reflects the combined influence of elevated neutrophils, which rise in response to inflammation, and reduced albumin levels, which often accompany systemic stress, chronic disease, and malnutrition. As a result, higher NPAR values generally correlate with more severe disease activity and worse clinical outcomes. Despite its utility, clinicians must interpret NPAR cautiously, as levels may be influenced by liver dysfunction, nephrotic syndrome, malnutrition, or medication-related changes in neutrophil counts.
Overall, the study supports the role of NPAR as a promising inflammatory biomarker in osteoarthritis and highlights its potential clinical relevance, particularly for identifying at risk individuals in whom traditional markers may be less informative.
References
- Lian Q, Liu Y, Tian F, Hu Y, Li H, Ding H, Zhang L. Assessment of neutrophil percentage to albumin ratio as a diagnostic biomarker for osteoarthritis: A cross-sectional study utilizing NHANES data. Medicine (Baltimore). 2025 Nov 7;104(45):e45681.
- Ding W, La R, Wang S, He Z, Jiang D, Zhang Z, Ni H, Xu W, Huang L, Wu Q. Associations between neutrophil percentage to albumin ratio and rheumatoid arthritis versus osteoarthritis: a comprehensive analysis utilizing the NHANES database. Front Immunol. 2025 Jan 23;16:1436311.