title: Estimating renal survival using the ANCA-associated GN classification.
abstract: A histopathological classification system for ANCA-associated vasculitis was recently published, but whether this system predicts renal outcome requires validation. Here, we analyzed data from 164 consecutive patients with biopsy-proven renal involvement of ANCA-associated vasculitis. The ANCA-associated GN (AGN) classification categorizes patients as having focal, mixed, crescentic, or sclerotic GN. Five-year renal survival rates by categories of the AGN classification scheme were 91% for focal, 69% for mixed, and 64% for crescentic (log-rank P<0.0001). Only one patient was classified as sclerotic. Furthermore, the percentage of normal glomeruli found on biopsy estimated renal survival with the same precision as did the AGN classification scheme. Patients classified as crescentic or mixed, however, had worse survival when the percentage of normal glomeruli was <25%. In conclusion, the AGN classification for renal biopsy specimens is a practical and informative scheme with which to categorize patients with ANCA-associated vasculitis, but adding the percentage of normal glomeruli to the system seems to improve its predictive value.
authors.affiliation: Department of Internal Medicine, Division of Clinical and Experimental Immunology, Maastricht University Medical Centre, The Netherlands.
authors.forename: Marc
authors.initials: M
authors.lastname: Hilhorst
authors.forename: Benjamin
authors.initials: B
authors.lastname: Wilde
authors.forename: Peter
authors.initials: P
authors.lastname: van Breda Vriesman
authors.forename: Pieter
authors.initials: P
authors.lastname: van Paassen
authors.forename: Jan Willem
authors.initials: JW
authors.lastname: Cohen Tervaert
mesh_terms: D000368:Aged; D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000453:epidemiology*; D001706:Biopsy; D015897:Comorbidity; D005260:Female; D005921:Glomerulonephritis / Q000145:classification* / Q000453:epidemiology*; D006801:Humans; D007668:Kidney / Q000473:pathology / Q000503:physiopathology*; D007678:Kidney Glomerulus / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies