ORIGINAL RESEARCH article
Front. Med.
Sec. Rheumatology
Volume 12 - 2025 | doi: 10.3389/fmed.2025.1624527
The C-Reactive Protein-to-Albumin Ratio as a Diagnostic Biomarker for Rheumatoid Arthritis: A Cross-Sectional NHANES Analysis
Provisionally accepted
- Cangzhou Central Hospital, Cangzhou, China
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Background:Rheumatoid arthritis (RA) is a chronic inflammatory disorder that leads to joint damage, cartilage and bone destruction, and functional disability. The C-Reactive Protein to Albumin Ratio (CAR), an emerging biomarker reflecting systemic inflammation and nutritional status, has demonstrated prognostic value in various diseases. However, its utility in predicting clinical outcomes in RA patients remains underexplored, warranting further investigation to assess its potential role in disease management and prognosis.This cross-sectional study investigates the potential relationship between CAR and RA in US adults, develops a clinical prediction model, and validates its effectiveness.Objective: To investigate the association between the C-reactive protein to albumin ratio (CAR) and rheumatoid arthritis (RA) using data from the National Health and Nutrition Examination Survey (NHANES) Methods: This large-scale, cross-sectional study analyzed data from the National Health and Nutrition Examination Survey (NHANES) database between 1999 and 2018 (excluding 2011-2014). The C-reactive protein to albumin ratio (CAR) was calculated as the ratio of C-reactive protein (CRP) to albumin (ALB) levels. Rheumatoid arthritis (RA) status was identified through self-reported questionnaire data. Weighted multivariate regression models and subgroup analyses were used to examine the association between CAR and RA. Restricted cubic splines (RCS) were employed to evaluate potential non-linear relationships, and sensitivity analyses were conducted to assess the robustness of the results. Least absolute shrinkage and selection operator (LASSO) were utilized for variable selection in the prediction model. Decision curve analysis (DCA) and receiver operating characteristic (ROC) curve analysis were applied to assess the predictive performance of the models.Results:This study included a total of 20,733 patients, among whom 1,744 individuals (4.95%) were diagnosed with rheumatoid arthritis (RA). After controlling for all covariates, the results of multivariate logistic regression analysis indicated a statistically significant correlation between higher Ln(CAR) levels and the increased incidence of RA (OR:1.77(95% CI,1.39-2.25); p < 0.001). The interaction test results showed that there was no statistically significant influence in this specific association. RCS regression modeling demonstrated a linear relationship between Ln-CAR and RA risk.After variable screening, we constructed an RA prediction model incorporating CAR, and the results were visualized using a nomogram.
Keywords: C-reactive protein to albumin ratio, Rheumatoid arthritis, NHANES, systemic inflammation, prognostic biomarker
Received: 07 May 2025; Accepted: 16 Jun 2025.
Copyright: © 2025 Yang, Sang, Liu and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Fan Yang, Cangzhou Central Hospital, Cangzhou, China
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