Systemic immune-inflammation index and systemic inflammation response index correlate with disease activity in systemic lupus erythematosus

OBJECTIVE: The objective of this meta-analysis was to assess the relationships of the systemic immune-inflammation index (SII) and the systemic inflammation response index (SIRI) with systemic lupus erythematosus (SLE) and to determine the correlation of these indices with disease activity as measured by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). METHODS: We performed a systematic search of Medline, Embase, and the Web of Science databases to identify eligible studies. Standardized mean differences (SMDs) were calculated to compare SII and SIRI between individuals with SLE and healthy controls. Pooled correlation coefficients were used to estimate the strength of the associations between SII, SIRI, and SLEDAI scores. RESULTS: Eleven studies qualified for inclusion in the meta-analysis. The aggregated analyses indicated that SII was markedly higher in SLE patients than in healthy controls (SMD 0.961; 95% CI 0.632-1.291; p < 0.001), a finding that remained consistent irrespective of data type, study sample size, or lupus nephritis status. Similarly, SIRI was elevated in those with SLE (SMD 0.761; 95% CI 0.320-1.203; p = 0.001). Analysis of correlation revealed that SII had a statistically significant positive association with SLEDAI scores (correlation coefficient 0.322; 95% CI 0.146-0.478; p < 0.001), supporting its value as a marker of increased disease activity. In contrast, SIRI did not present a significant association with SLEDAI (correlation coefficient 0.133; 95% CI -0.119 to 0.369; p = 0.302). CONCLUSION: This meta-analysis provides evidence that both SII and SIRI are significantly increased in patients with SLE compared to healthy controls, supporting their utility as inflammatory biomarkers in SLE. Additionally, SII demonstrated a moderate positive correlation with disease activity, emphasizing its relevance for evaluating SLE severity.