Correlation Between Systemic Inflammation Response Index and Systemic Immune-Inflammation Index and Disease Activity of Lupus Nephritis in Children

Objectives: Lupus nephritis (LN) is a severe manifestation of pediatric systemic lupus erythematosus (SLE) requiring accurate disease activity assessment. This study evaluated the association of the Systemic Inflammation Response Index (SIRI) and the Systemic Immune-Inflammation Index (SII) with disease activity in children with LN. Methods: In this cross-sectional study, 52 children with LN aged 1 month to 18 years treated at Dr. Hasan Sadikin General Hospital, Indonesia, were included. SIRI and SII were calculated from complete blood counts, and disease activity was assessed using the Mexican Modification of the SLE Disease Activity Index (Mex-SLEDAI). Correlations were analyzed using Spearman’s test. Results: Median SIRI and SII values were 1511 and 789,544, respectively, with a median Mex-SLEDAI score of 7. SIRI showed a moderate positive correlation with disease activity (r = 0.443; p < 0.001), and SII also showed a significant positive correlation (r = 0.390; p = 0.004). Both indices increased with higher LN activity. Conclusions: SIRI and SII were significantly associated with disease activity in pediatric LN, with SIRI yielding a numerically higher correlation coefficient, though this difference was not formally compared. These indices may serve as simple, non-invasive biomarkers for assessing inflammatory activity in children with lupus nephritis.