Background/Purpose: Renal involvement in ANCA-associated vasculitides (AAV) is an organ- and life-threatening manifestation and therefore an important prognostic factor. However, the identification of predictive factors for renal failure remains a major challenge. Indeed, it may influence the intensity of induction treatment strategies. Furthermore, the benefit of plasma exchange (PLEX) has been questioned in recent years. The aim of this study is to describe the clinical outcome of patients requiring renal replacement therapy (RRT) at baseline and to identify clinical, biological and histological factors at baseline associated with their prognosis at one year.

Methods: This retrospective multicentre study included patients with anti-myeloperoxidase or proteinase 3 AAV with biopsy-proven renal involvement. Characteristics were evaluated stratified by dialysis requirement at baseline to identify determinants of renal prognosis. The primary composite outcome was the occurrence of death or end-stage renal disease at one year. Prognostic outcomes were modelized by generalized linear models to quantify the impact of predictors.

Results: Of the 395 patients enrolled, 106 (26.8%) were on dialysis at baseline. The mean age was 63.1±13.6 years and age was not associated with RRT at baseline (p=0.521). PR3-ANCA was associated to a greater prevalence of renal failure.

Among patients with dialysis at baseline, 61 (57.5%) achieved the one-year composite outcome of death or end-stage kidney disease (ESKD), whereas only 29 (10.0%) patients RRT-free at baseline reached the outcome at one year (p< 0,001). Thirty (28.3%) patients with RRT at baseline had an eGFR at one year superior to 30 mL/min/1,73m², with a null median of eGFR recuperation at one year (0,00 [IQR 0.00-31.5 mL/min/1,73m²]).

Among patients requiring dialysis at baseline, age at diagnosis was not associated with the composite outcome at one year in multivariate analysis (p=0.744). MPO-ANCA were associated with a higher prevalence of RRT or death at one year (OR 3,08; 95%CI 1.21–8.14; p = 0.02). In addition, Brix score at baseline was associated with worse renal prognosis at one year (OR 1.40; 95%CI 1.16–1.73; p=0.001).

Of the patients requiring dialysis at baseline, 80 (75.5%) underwent PLEX. Plasma exchanges were independently associated with a higher estimated glomerular filtration rate (eGFR) at one year of 9.15 mL/min/1.73m² [95%CI 0.26-18.04] (p=0.044). In addition, 41 (91.1%) of the surviving patients who were weaned from RRT at one year had received PLEX, whereas only 39 (63.9%) of the patients with the composite outcome (death or RRT at one year) had received PLEX (p=0.003). Thus, PLEX was associated with a reduced risk of one-year RRT or death in patients receiving dialysis at baseline (OR 0.24, 95%CI 0.06-0.82).

Conclusion: This study describes the clinical evolution of patients with AAV requiring RRT at baseline. It shows a strong association between plasma exchange and improvement in renal function with a higher rate of dialysis weaning. It opens perspectives for further studies in patients who benefit more from PLEX therapy.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/renal-prognosis-of-dialysis-dependent-patients-at-baseline-in-anca-associated-vasculitis/