ORIGINAL RESEARCH article
Front. Med.
Sec. Hematology
This article is part of the Research TopicNew Insights in Pediatric Rheumatology: Advances in Diagnosis and TreatmentView all 4 articles
The role of systemic immune-inflammation index in differentiation of juvenile idiopathic arthritis from reactive arthritis among Chinese children
Provisionally accepted
- Capital Medical University, Beijing, China
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Objective The study aims to evaluate the diagnostic value and clinical significance of the Systemic Immune-Inflammation Index (SII) in differentiating juvenile idiopathic arthritis (JIA) from reactive arthritis (ReA) in Chinese children aged under 18. Methods This study conducted a retrospective analysis of 865 arthritis patients treated at Capital Children's Medical Center Affiliated to Capital Medical University between January 2020 and January 2025. Spearman correlation analysis was used to assess the relationship between SII and inflammatory biomarkers. Logistic regression analysis was performed to assess the independence of SII in JIA diagnosis, and the diagnostic performance was evaluated using receiver operating characteristic (ROC) curves. Results The diagnostic performance for differentiating JIA from ReA was evaluated using ROC curves. The area under the curve (AUC) values were as follows: SII (AUC=0.83), c-reactive protein (CRP) (AUC=0.81), erythrocyte sedimentation rate (ESR) (AUC=0.78), hemoglobin (Hb) (AUC=0.75). To statistically compare these AUC values, we implemented the DeLong test. The DeLong test results showed that the AUC of SII was significantly higher than that of CRP (P=0.045), ESR (P=0.012), and Hb (P=0.003), indicating that SII is a superior predictor for differentiating JIA from ReA. Eleven biomarkers are associated with disease status, among which joint type, red cell distribution width (RDW), neutrophil count (N), platelet count (PLT),, SII, platelet-to-lymphocyte ratio (PLR), and neutrophil-to-lymphocyte ratio (NLR) are identified as independent risk factors, while Hb, lymphocyte count (L), and platelet width-to-lymphocyte ratio (PWR)[platelet count ÷ white blood cell count] serve as protective factors. SII exhibits correlations with N, PLT, and L, with stronger associations observed in the JIA cohort. Conclusion The SII values in JIA patients are higher than those in ReA and are associated with disease activity. This suggests that SII is applicable for early differential diagnosis between these two types of arthritis.
Keywords: Routine blood test, Inflammation, juvenile idiopathic arthritis, reactive arthritis, systemic immune-inflammation index
Received: 07 Sep 2025; Accepted: 24 Nov 2025.
Copyright: © 2025 Ren, Wang and Liu. 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: Zhenjiang Liu
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