Risk factors of poor outcomes in ANCA-associated vasculitis: a single-center study

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare disease with high rate of end-stage kidney disease (ESKD) and mortality. We aimed to investigate the risk factors for ESKD and/or death in AAV patients.

Seventy-eight AAV patients diagnosed from November 2013 to December 2022 were included. Study endpoints included ESKD or death and composite endpoints. Cox regression models were used to adjust for potential baseline confounders.

Among the 78 cases, there were 16 cases of ESKD, 15 cases of death, and 27 cases of composite endpoint during follow-up. After adjusting for baseline characteristics, baseline blood urea nitrogen (BUN) level (adjusted hazard ratio [HR] 1.07, 95%Cl 1.04-1.10) was an independent risk factor for composite endpoints (ESKD and/or death) in AAV patients. ROC curve analysis showed that the optimal cutoff of BUN level was 19.5 mmol/L for ESKD and death (AUC: 0.760; 95% CI: 0.65-0.87). Baseline BUN levels (HR per 1 mmol/L: 1.09, 95% CI 1.05-1.23) and white blood cell (WBC) counts (HR per 1,000/μL: 1.22, 95% CI 1.07-1.40) were independent risk factors for ESKD in AAV. Cardiovascular involvement (HR 8.74, 95%Cl 2.20-34.73), NLR (HR 1.04, 95%Cl 1.01-1.08), and antiplatelet drug use (HR 6.79, 95%Cl 1.33-34.62) were independent risk factors for death in AAV.

These findings suggest that high baseline BUN level was an independent predictor for ESKD and/or death in AAV patients, even after correction for co-founders including Scr. BUN might constitute an independent, easily available and important parameter for risk stratification in AAV.