title: The Oxford classification of IgA nephropathy: a retrospective analysis.
abstract: OBJECTIVE
  The Oxford classification of IgA nephropathy (IgAN) assesses the presence of mesangial hypercellularity ≥50% (M1 vs. 0), endocapillary proliferation (E1 vs. 0), segmental glomerulosclerosis (S1 vs. 0), tubular atrophy/interstitial fibrosis >25 or 50% (T1 or 2 vs. 0), and has been reported as having prognostic value. We studied the clinical significance of the classification in our adult patients with IgAN.
  
  
  METHODS
  Retrospective study of 54 patients with biopsy-proven IgAN seen from 1983 to 2009. The correlation between the Oxford classification and baseline renal function was assessed. The primary endpoint was a 50% reduction in eGFR or end-stage renal disease. Predictors for progression to the endpoint were determined by multivariate analyses.
  
  
  RESULTS
  Patients were 41 ± 15 years of age with a serum creatinine of 1.5 ± 0.8 mg/dl, eGFR of 61 ± 24 ml/min/1.73 m(2), and proteinuria of 2.0 ± 1.6 g/day. Oxford classifications were as follows: M1 = 72%, E1 = 20%, S1 = 81%, and T1 = 13%/T2 = 22%. During the follow-up of 5.8 ± 4.8 years, 19% of patients reached the primary endpoint. While the Oxford classification was associated with progressive renal disease, only the T score (T0, T1, T2) was predictive of outcome with 6, 29, and 50% of patients (p = 0.002) reaching the primary endpoint. The 10-year renal survival for T0, T1, and T2 was 100, 50, and 17%, respectively (p < 0.001). By multivariate analysis, the hazard ratio for reaching the primary endpoint was 32 for patients with T ≥1 versus T0 (p = 0.01).
  
  
  CONCLUSIONS
  In our experience, the Oxford classification predicts progressive renal disease, but the degree of tubulointerstitial fibrosis was the only feature independently predictive of outcome.
authors.affiliation: Department of Nephrology, Rush University Medical Center, Chicago, IL 60607, USA.
authors.forename: Timothy
authors.initials: T
authors.lastname: Yau
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Korbet
authors.forename: Melvin M
authors.initials: MM
authors.lastname: Schwartz
authors.forename: David J
authors.initials: DJ
authors.lastname: Cimbaluk
mesh_terms: D000328:Adult; D005260:Female; D005922:Glomerulonephritis, IGA / Q000145:classification* / Q000175:diagnosis; D006801:Humans; D008297:Male; D012189:Retrospective Studies