Systemic Immune-Inflammation Index Predicts A Reduced Risk Of End-Stage Renal Disease In Chinese Patients With Myeloperoxidase-Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis: A Retrospective Observational Study

Chronic inflammation has been indicated to be important in the pathogenesis of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). The systemic immune-inflammation index (SII) is a novel marker of inflammation. The present study was thus performed to explore the association between the SII at diagnosis and inflammatory response and disease activity in Chinese patients with myeloperoxidase (MPO)-AAV. Furthermore, it was evaluated whether the SII is able to predict the progression to end-stage renal disease (ESRD) and patient survival. A total of 190 patients with MPO-AAV were included in the present study. The baseline SII was positively correlated with C-reactive protein (CRP; r=0.274, P<0.0001) and the erythrocyte sedimentation rate (ESR; r=0.481, P<0.0001). However, the SII had no obvious correlation with the Birmingham vasculitis activity score. Patients with SII >= 2,136.45 exhibited better cumulative renal survival rates than those with SII<2,136.45 (P=0.001). However, no significant difference in patient survival was indicated between patients with SII >= 2,136.45 and those with SII<2,136.45 at diagnosis. In conclusion, the SII was positively correlated with CRP and ESR in Chinese patients with MPO-AAV. Furthermore, the SII may be an independent factor associated with a reduced risk of ESRD.