Histopathologic and clinical predictors of kidney outcomes in ANCA-associated vasculitis

Sharon Ford, Kevan R Polkinghorne, Anthony Longano, John Dowling, Sukhpal Dayan, Peter Kerr, Stephen Roger Holdsworth, Arthur Richard Kitching, Shaun Andrew Summers

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48 Citations (Scopus)

Abstract

BACKGROUND: A predictive histologic classification recently was proposed to determine the prognostic value of kidney biopsy in patients with antineutrophil cytoplasmic antibody-associated renal vasculitis (AAV). STUDY DESIGN: A dual-purpose retrospective observational cohort study to assess the reproducibility of the new classification and clinical variables that predict outcomes. SETTING PARTICIPANTS: 169 consecutive patients with AAV were identified; 145 were included in the reproducibility study, and 120, in the outcomes study. PREDICTOR: Kidney biopsy specimens were classified according to the predominant glomerular lesion: focal, mixed, crescentic, and sclerotic. An assessment of tubular atrophy also was performed. OUTCOMES: The primary outcome was time to end-stage kidney disease or all-cause mortality, modeled using Cox regression analysis. MEASUREMENTS: Estimated glomerular filtration rate, requirement for renal replacement therapy. RESULTS: For the reproducibility study, the overall inter-rater reliability of the classification demonstrated variability among 3 histopathologists (intraclass correlation coefficient, 0.48; 95 CI, 0.38-0.57; kappa statistic=0.46). Although agreement was high in the sclerotic group (kappa=0.70), it was less consistent in other groups (kappa=0.51, kappa=0.47, and kappa=0.23 for crescentic, focal, and mixed, respectively). For the clinical outcomes study, patients with sclerotic patterns of glomerular injury displayed the worst outcomes. Patients with focal (HR, 0.26; 95 CI, 0.12-0.58; P=0.001), crescentic (HR, 0.33; 95 CI, 0.16-0.69; P=0.003), and mixed (HR, 0.39; 95 CI, 0.18-0.81; P=0.01) patterns of injury had lower risk of the primary outcome. Tubular atrophy correlated with outcome, and advanced injury was associated with worse outcomes (HR, 5.9; 95 CI, 2.25-15.47; P
Original languageEnglish
Pages (from-to)227 - 235
Number of pages9
JournalAmerican Journal of Kidney Diseases
Volume63
Issue number2
DOIs
Publication statusPublished - 2014

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