Clinical Predictors of Outcome in Patients with Anti-neutrophil Cytoplasmic Autoantibody-related Renal Vasculitis: Experiences from a Single-center

Abstract

Background: Primary anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) is a chronic autoimmune disease associated with multisystem dysfunction. Renal involvement is common and closely associated with outcome. The purpose of this study was to investigate the clinical determinants of mortality of patients with AAV-related renal injury in the first 2 years after diagnosis in a single West Chinese center.

Methods: Demographic and laboratory parameters of 123 consecutive patients with AAV-related renal injury diagnosed in Renal Division and Institute of Nephrology, Sichuan Provincial People's Hospital between 2004 and 2012 were collected retrospectively. All patients were followed up for 2 years after diagnosis. Survivors were compared with nonsurvivors to identify the clinical baseline variables associated with mortality. Multivariate Cox regression model was used to determine the independent predictors of mortality.

Results: Of the 123 patients, 46 (37.4%) died by the end of 2 years after diagnosis, with 41 (33.3%) patients dying within the first 12 months. In comparison with the survivors, Birmingham Vasculitis Activity Score (BVAS), the incidence of pulmonary hemorrhage and digestive system (DS) involvement, serum creatinine, and erythrocyte sedimentation rate were significantly higher in nonsurvivors, whereas lymphocyte counts, hemoglobin, and complement 3 (C3) were significantly lower. Renal replacement therapy was more common in nonsurvivors. High BVAS (hazard ratio [HR] = 1.058, 95% confidence interval [CI]: 1.002-1.117; P = 0.042), pulmonary hemorrhage (HR = 1.970, 95% CI: 1.033-3.757; P = 0.04), DS involvement (HR = 2.911, 95% CI: 1.212-6.911; P = 0.017), and serum creatinine >400 μmol/L (HR = 2.910, 95% CI: 1.271-6.664; P = 0.012) were independent predictors of death in patients with AAV-related renal injury.

Conclusions: Patients with AAV-related renal injury have high early mortality. Those with high BVAS (particularly with pulmonary or DS involvement) and serious renal dysfunction should receive aggressive therapy and careful monitoring to reduce the occurrence of adverse events and improve prognosis.

Figure 1

Organ involvement of patients with ANCA-related renal vasculitis at diagnosis. Oph: Ophthalmic and mucocutaneous; ENT: Ear, nose, and throat; PS: Pulmonary system; DS: Digestive system; CVS: Cardiovascular system; NS: Nervous system; ANCA: Anti-neutrophil cytoplasmic autoantibody.

Figure 2

Kaplan-Meier analysis of the probability of Relapse-free survival of patients with ANCA-related renal vasculitis achieving remission. ANCA: Anti-neutrophil cytoplasmic autoantibody.

Figure 3

Kaplan-Meier survival curve of 123 patients with ANCA-related renal vasculitis. ANCA: Anti-neutrophil cytoplasmic autoantibody.