Systemic Immune Inflammation Index in Ankylosing Spondylitis Patients

Abstract

Objective: Our objective was to assess the relationship between disease activity and the systemic immune-inflammation index [SII; (platelet count × neutrophil count / lymphocyte count)] in individuals with ankylosing spondylitis (AS). Materials and Methods: A total of 201 participants (130 AS patients and 71 healthy volunteers) aged 18-65 years were included in this single center cross-sectional study. Based on their ratings on the Bath Ankylosing Spondylitis Disease Activity index (BASDAI), patients with AS were split into two groups: remission (n=90, those with BASDAI 4). The study employed Spearman correlation analysis to assess the relationship between SII and C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), BASDAI, Ankylosing Spondylitis Disease Activity score-ESR (ASDAS-ESR), and ASDAS-CRP. The effectiveness of SII and other measures in evaluating the disease activity in the active AS and remission AS groups was ascertained using receiver operating characteristic curve analysis. Results: SII values were significantly higher in the AS group than healthy controls, as well as in the active AS group than AS patients in remission (p<0.001 for each). SII values were positively correlated with CRP [Spearman correlation coefficient (rs): 0.384, p<0.001], ESR (rs: 0.243, p=0.005), BASDAI (rs: 0.668, p<0.001), ASDAS-ESR (rs: 0.619, p<0.001) and ASDAS-CRP (rs: 0.700, p<0.001) values. The optimal cut-off value for the determination of AS disease activity was found to be 530.22x109/L (area under the curve: 0.902, 95% confidence interval: 0.838-0.947, sensitivity: 72.50% and specificity: 92.22%). Conclusion: When assessing the activity of AS disease, SII appears to be a useful biomarker.

Keywords

• ankylosing spondylitis
• c-reactive protein
• neutrophil to lymphocyte ratio
• systemic immune-inflammation index