A Study of the Correlation Between the Inflammatory Index and Disease Activity in Ulcerative Colitis

To analyze the level of systemic immune-inflammatory index (SII) in patients with ulcerative colitis (UC) and assess its relationship with disease activity.

This study included 616 UC patients and 211 healthy controls. Disease activity was assessed using the modified Mayo score, categorizing patients into remission (n=115) and active (n=501) groups, with the latter further stratified into mild, moderate, and severe activity. We compared multiple inflammatory indices-including SII, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), neutrophil percentage-albumin ratio (NPAR), and others-between groups. Spearman correlation and ROC curve analyses were used to evaluate their associations with disease activity and predictive value for active and severe UC.

SII, NLR, PLR, NPAR, and several other indices were significantly higher in the UC group than controls, while lymphocyte-to-monocyte ratio (LMR) and LHR were lower (all P<0.05). Most indices were also elevated in active versus remission UC (P<0.05), and showed significant differences across severity subgroups (P<0.05), with SII, NLR, NPAR, NHR, and MHR increasing with severity. Spearman analysis revealed positive correlations between these markers and disease activity/severity (P<0.001). ROC analysis demonstrated significant predictive value for active and severe UC (AUC>0.60, P<0.001), with NPAR exhibiting the highest efficacy (AUC=0.854).

SII, NLR, PLR, NPAR, and other inflammatory indices are useful non-invasive biomarkers for assessing UC disease activity and severity, with NPAR showing the strongest predictive performance.