title: Validation of the Oxford classification of IgA nephropathy.
abstract: The Oxford classification of IgA nephropathy (IgAN) identified four pathological elements that were of prognostic value and additive to known clinical and laboratory variables in predicting patient outcome. These features are segmental glomerulosclerosis/adhesion, mesangial hypercellularity, endocapillary proliferation, and tubular atrophy/interstitial fibrosis. Here, we tested the Oxford results using an independent cohort of 187 adults and children with IgAN from 4 centers in North America by comparing the performance of the logistic regression model and the predictive value of each of the four lesions in both data sets. The cohorts had similar clinical and histological findings, presentations, and clinicopathological correlations. During follow-up, however, the North American cohort received more immunosuppressive and antihypertensive therapies. Identifying patients with a rapid decline in the rate of renal function using the logistic model from the original study in the validation data set was good (c-statistic 0.75), although less precise than in the original study (0.82). Individually, each pathological variable offered the same predictive value in both cohorts except mesangial hypercellularity, which was a weaker predictor. Thus, this North American cohort validated the Oxford IgAN classification and supports its utilization. Further studies are needed to determine the relationship to the impact of treatment and to define the value of the mesangial hypercellularity score.
authors.affiliation: Division of Nephrology, Toronto General Hospital, University of Toronto, Ontario, Canada.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Herzenberg
authors.forename: Agnes B
authors.initials: AB
authors.lastname: Fogo
authors.forename: Heather N
authors.initials: HN
authors.lastname: Reich
authors.forename: Stéphan
authors.initials: S
authors.lastname: Troyanov
authors.forename: Nuket
authors.initials: N
authors.lastname: Bavbek
authors.forename: Alfonso E
authors.initials: AE
authors.lastname: Massat
authors.forename: Tracy E
authors.initials: TE
authors.lastname: Hunley
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Hladunewich
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Julian
authors.forename: Fernando C
authors.initials: FC
authors.lastname: Fervenza
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Cattran
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001284:Atrophy; D001706:Biopsy; D002170:Canada; D002196:Capillaries / Q000473:pathology; D016009:Chi-Square Distribution; D005260:Female; D005355:Fibrosis; D005919:Glomerular Filtration Rate; D005922:Glomerulonephritis, IGA / Q000145:classification* / Q000175:diagnosis* / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D005923:Glomerulosclerosis, Focal Segmental / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007668:Kidney / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology; D016018:Least-Squares Analysis; D016015:Logistic Models; D008297:Male; D050527:Mesangial Cells / Q000473:pathology; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D009626:Terminology as Topic; D013997:Time Factors; D014481:United States; D055815:Young Adult
chemical_list: D000959:Antihypertensive Agents; D007166:Immunosuppressive Agents