Kidney biopsy chronicity grading in antineutrophil cytoplasmic antibody-associated vasculitis

Marta Casal Moura, Fernando C. Fervenza, Ulrich Specks, Sanjeev M Sethi

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND: Kidney biopsy is valuable for prognostic assessment of renal outcomes in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) with glomerulonephritis (AAV-GN) but the impact of chronic changes is not determined. METHODS: We conducted a retrospective cohort study of myeloperoxidase (MPO)- or proteinase 3 (PR3)-ANCA-positive patients with AAV and active renal disease. We applied the Mayo Clinic Chronicity Score (MCCS) and validated and evaluated its implications on outcome prediction in AAV-GN. RESULTS: We analyzed 329 patients with kidney biopsies available to score. The extent of chronicity was graded by MCCS as minimal [102 (31.0%)], mild [106 (32.2%)], moderate [86 (26.1%)] and severe [35 (10.6%)]. The MCCS grades correlated with the degree of renal function impairment at presentation [mean estimated glomerular filtration rate (eGFR) 48.3 versus 29.2 versus 23.7 versus 18.5 mL/min/1.73 m2, respectively; P < 0.0001]. Higher degrees of the individual components of the MCCS (glomerulosclerosis, interstitial fibrosis, tubular atrophy and arteriosclerosis) were associated with lower median eGFR (P < 0.0001) and decreased event-free [kidney failure (KF) and death] survival (P = 0.002, P < 0.0001, P < 0.0001 and P = 0.017, respectively). Patients with lower MCCS grades recovered renal function more frequently (P < 0.0001). Increasing MCCS grades were associated with decreased renal recovery (P = 0.001), more frequent events and shorter time to KF (P < 0.0001), KF and death (P < 0.0001) and death (P = 0.042), independent of the remission induction treatment used (cyclophosphamide or rituximab). The MCCS stratified renal outcomes for each MCCS grade and can be used in clinical practice as a cutoff for KF prediction (MCCS ≥4). CONCLUSIONS: Chronic changes on kidney histology independently predict renal function, outcomes and response to treatment in AAV-GN.

Original languageEnglish (US)
Pages (from-to)1710-1721
Number of pages12
JournalNephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association
Volume37
Issue number9
DOIs
StatePublished - Aug 22 2022

Keywords

  • ANCA
  • glomerulonephritis
  • kidney biopsy
  • Mayo Clinic Chronicity Score

ASJC Scopus subject areas

  • Nephrology
  • Transplantation

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