Association Between Neutrophil Percentage to Albumin Ratio and Disease Activity in Hospitalized Patients with Rheumatoid Arthritis: A Cross-Sectional Study.

PURPOSE: The neutrophil percentage-to-albumin ratio (NPAR) is a readily accessible yet underexplored inflammatory marker in rheumatoid arthritis (RA). This study aimed to explore the association of NPAR with disease activity and to evaluate its performance in identifying high disease activity.

PATIENTS AND

METHODS

A cross-sectional analysis was performed among 1,191 hospitalized RA patients admitted to Xingtai People's Hospital between March 2022 and December 2024. NPAR was computed as (neutrophil percentage × 100) divided by serum albumin (g/dL). Disease activity was quantified using the 28-joint Disease Activity Score (DAS28) by erythrocyte sedimentation rate (DAS28-ESR) and C-reactive protein (DAS28-CRP). Multiple linear regression models were applied to determine the independent association between NPAR and disease activity, and receiver operating characteristic curve analyses were conducted to examine the ability of NPAR to identify high disease activity.

RESULTS

989 patients met the inclusion criteria for final analysis (average age 57.6 years; 78.0% women), 95.6% exhibited moderate-to-high disease activity. After fully adjusting for variables, NPAR remained independently and positively associated with disease activity. Each standard deviation increase in NPAR was associated with an increase of 0.37 in DAS28-CRP and 0.34 in DAS28-ESR. A clear dose-response relationship was observed across increasing NPAR tertiles. In addition, NPAR demonstrated moderate discriminatory performance for distinguishing high from moderate disease activity, with areas under the ROC curve of 0.75 (95% CI, 0.72-0.79) for DAS28-CRP and 0.71 (95% CI, 0.68-0.75) for DAS28-ESR. Notably, NPAR showed better discriminatory ability than other conventional complete blood count-derived indices, including the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), platelet-to-albumin ratio (PAR), and neutrophil-to-albumin ratio (NAR).

CONCLUSION

In hospitalized patients with moderate-to-high disease activity, NPAR was positively associated with RA disease activity and showed meaningful discriminatory performance for identifying high disease states.