Effect of Baseline Dialysis and Plasma Exchange on Renal Prognosis in Patients With Antineutrophil Cytoplasmic Autoantibody-Associated Vasculitis.

Introduction: The identification of prognostic factors for renal failure in antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) remains a challenge. The benefit of plasma exchange (PLEX) has been questioned, and the target population remains to be defined. We investigated the outcome of patients requiring renal replacement therapy (RRT) at baseline and factors associated with their prognosis at 1 year. Methods: This retrospective multicenter study evaluated the 1-year composite end point of death or end-stage kidney disease (ESKD) in patients with biopsy-proven renal AAV involvement. Results: Of the 394 patients included, 105 (26.6%) were on dialysis at baseline. Of these, 60 (57.1%) reached the composite end point compared with 29 patients (10.0%) who were not on RRT at baseline (P < 0.001). On multivariate analysis, age and sex were not associated with the composite outcome (P = 0.945 and P = 0.154, respectively); however, myeloperoxidase (MPO)-ANCA was (odds ratio [OR]: 3.60; 95% confidence interval [CI]: 1.79-7.60), as was a high baseline histologic renal risk score (OR: 1.29; 95% CI 1.17-1.44). The most strongly associated factor remained the need for dialysis at baseline (OR: 10.91; 95% CI: 5.52-22.70). Of the 91 patients surviving after requiring dialysis at baseline, 45 were weaned from RRT (49.5%) at 1 year, and PLEX was independently associated with a reduced risk of the composite outcome (OR: 0.23, 95% CI: 0.05-0.80). Conclusion: MPO-ANCA, need for dialysis, and high histological renal risk score at baseline were associated with the 1-year composite end point of death or ESKD. Almost half of the patients on dialysis at baseline were off dialysis at 1 year, with a better prognosis in those who had received PLEX.