To investigate the systemic immune-inflammation index (SII) as a potential adjunctive biomarker in rheumatic diseases (RDs).
Approach:
Data Sources: Search conducted in PubMed, Web of Science, and Scopus up to May 27, 2023.
Key Findings:
Patients with RDs had significantly higher SII values compared to healthy controls (SMD = 0.83, 95% CI 0.69 to 0.97; p<0.001).
No significant associations were found between effect size and demographic or clinical characteristics.
Subgroup analysis showed significant SII differences in studies from Asia, Africa, and Europe, with lower heterogeneity in European studies.
Significant SII differences were observed across most RD categories, except fibromyalgia and connective tissue disease.
Interpretation:
The SII is higher in RD patients than in healthy controls, suggesting its potential as an adjunctive biomarker for diagnosis and monitoring.
Limitations:
Very low certainty of evidence due to high heterogeneity among studies.
Lack of significant associations in meta-regression analysis.
Conclusion:
Further evaluation of the SII in diverse RD populations is warranted to establish clinically useful thresholds and assess its diagnostic or prognostic performance.
