ANCA-associated vasculitis with renal involvement: an outcome analysis.

BACKGROUND: The anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides are a group of heterogeneous diseases. This study was undertaken to investigate the outcome of Wegener's granulomatosis (WG), microscopic polyangiitis (MPA) and renal-limited vasculitis (RLV). Furthermore, we analysed the differences in patients with proteinase 3-ANCA (PR3-ANCA) and those with myeloperoxidase-ANCA (MPO-ANCA), which have not been assessed in a homogeneously treated group of patients with renal involvement.

METHODS: In this retrospective analysis, 80 patients with a new diagnosis of WG, MPA or RLV with biopsy-proven renal involvement were followed over a median of 46.7 months (range: 0.8-181.9 months). All patients had induction treatment with cyclophosphamide and oral corticosteroids.

RESULTS: At the end of follow-up, 23% were dependent on dialysis. Renal survival was significantly worse in patients with WG compared with patients with MPA or RLV (P = 0.04). A higher rate of end-stage renal disease (ESRD) was noticed in PR3-ANCA- vs MPO-ANCA-positive patients. A total of 21 patients (26%) died. Predictors of patient mortality were development of ESRD, older age and the maximum creatinine in the first month. Mortality was found to be higher in patients with WG and was significantly higher in PR3-ANCA-positive cases (P = 0.02). The relative risk of death was 9.32 times higher in PR3-ANCA- vs MPO-ANCA-positive patients.

CONCLUSIONS: Our data underscore the pathogenetic potential of ANCA by demonstrating a more aggressive disease state and a poorer outcome in patients with PR3-ANCA.