LAUSR

Neutrophil-to-lymphocyte ratio (NLR) has been recently reported to be a promising inflammatory marker to assess systemic inflammation in many disorders. However, there are only a few studies looking at NLR in patients with myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This study was thus undertaken to explore the relationship between NLR at diagnosis with inflammatory response and disease activity among MPO-AAV patients in a single Chinese center. Furthermore, we evaluated whether NLR could predict the renal prognosis and patient outcome. 188 patients with MPO-AAV were included in this study. Baseline NLR was positively correlated with CRP ( r  = 0.404, P  < 0.001) and negatively with serum levels of C3 ( r  =  − 0.163, P  = 0.035), but it had no obvious correlation with Birmingham Vasculitis Activity Score (BVAS). Patients with MPO-AAV having NLR ≥ 9.53 exhibited higher risk for all-cause mortality than those having NLR < 9.53 ( P  < 0.0001). However, no significant difference was found in the kidney survival between patients having NLR ≥ 9.53 and those NLR < 9.53 at diagnosis. In multivariate analysis, NLR was positively associated with all-cause mortality ( P  = 0.037, HR = 1.98, 95% CI 1.04–3.78). There was no association between NLR with ESRD observed using univariate analysis or multivariate analysis. This large retrospective study of MPO-AAV patients in a single Chinese center demonstrates that NLR positively correlates with CRP and negatively correlates with serum levels of C3 in Chinese patients with MPO-AAV. Importantly, higher NLR predicts increased mortality and is, therefore, a useful independent prognostic in MPO-AAV.