Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) comprises a group of necrotizing vasculitis, primarily including microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA) and eosinophilic granulomatosis with polyangiitis (EGPA). Infections are a leading cause of mortality in AAV. While previous studies have explored infection risks in Western cohorts, significant geographic and genetic heterogeneity in AAV manifestations necessitates region-specific investigations, particularly in Asian populations where data remain sparse. This study aimed to identify clinical characteristics and independent predictors of infections in a Chinese AAV cohort.

A retrospective cohort study included 105 AAV patients admitted to a tertiary center in Southeast China. Clinical, laboratory and immunosuppressive therapy data were analyzed. Univariate and least absolute shrinkage and selection operator (LASSO) regression identified candidate predictors, followed by multivariable logistic regression to determine independent risk factors. Model performance was assessed using receiver operating characteristic (ROC) curves and the area under the curve (AUC).

Among 105 AAV patients, 57 (54.3%) developed infections. Infected patients exhibited higher disease activity (BVAS: 15.0 vs. 11.0, P<0.001), longer hospital stays (17.4 vs. 7.9 days, P<0.001), and greater cardiac (43.9% vs. 10.4%, P<0.001) and pulmonary involvements (54.4% vs. 20.8%, P<0.001). Elevated C-reactive protein (CRP) (44.7 vs. 3.7 mg/L), neutrophil-to-lymphocyte ratio (NLR) (0.68 vs. 0.23, P<0.001) and hypoalbuminemia (31.5 vs. 36.4 g/L, P<0.001) were found in AAV patients with infection. Multivariable analysis identified CRP (aOR=1.08, 95% CI: 1.04-1.13), NLR (aOR=8.34, 95% CI: 2.02-34.41), and cardiac involvement (aOR=5.88, 95% CI:1.09-31.67) as variables independently associated with infection. The composite model achieved an AUC of 0.93 (95% CI:0.88-0.97), outperforming individual biomarkers.

 Elevated CRP, NLR, and cardiac involvement were independent risks for predicting infection identified at admission in Chinese AAV patients. The integration of these markers into clinical practice may improve risk stratification and inform prophylactic strategies, thereby reducing infection-related morbidity. However, the limitations of this study lie in its retrospective design and limited sample size, which restrict the generalizability of the research findings. More clinical data is needed for future verification.