Validation Study of Oxford Classification of IgA Nephropathy in a Chinese Cohort.
Shaoshan Liang, Caihong Zeng, Sharon Phillips, Yu Shyr, Stephan Troyanov, Zhi-Hong Liu, Agnes B Fogo. Nanjing Research Institute of Nephrology, Jiangsu, China; Vanderbilt Unversity, Nashville, TN; Hôpital du Sacré-Coeur de Montréal, University of Montreal, QC, Canada
Background: The Oxford Classification of IgA Nephropathy (IgAN) identified four renal biopsy lesions of prognostic significance, namely mesangial hypercellularity, segmental glomerulosclerosis/adhesion, endocapillary proliferation and significant tubular atrophy/interstitial fibrosis. We now sought to validate whether these results were applicable in a Chinese cohort of patients.
Design: 213 adult Chinese patients from a single center, Nanjing Research Institute of Nephrology were studied. Inclusion criteria were as in the original Oxford cohort, with eGFR ≥ 30 ml/min and minimum of one year follow up, excluding patients with rapid progression in less than a year, or with no or minimal proteinuria, diabetes or other glomerulonephritis. Renal biopsies included at least 10 glomeruli.
Results: Patients were on average age 34 years (range 18-65), 46.5% female. MAP was higher than in the Oxford cohort (102 ± 22 mm Hg) at time of biopsy. RAS blockade at time of biopsy, and during followup were similar to the Oxford cohort. Follow up was on average 81 months (range 30-157 months). 21.1% received immunosuppression, 14.6% prednisone and 7.5% cyclophosphamide, all slightly less than the Oxford cohort. Rate of renal function decline was -2.2 ± 4.2 ml/min per 1.73 m2 per year, with 20.2% reaching 50% decline in renal function and 14.1% reaching ESRD, all similar to the original Oxford cohort. On average, 22.7 ± 8.8 (range 8-61) glomeruli were available. All Oxford classification variables were scored independently by two pathologists. Global sclerosis/advanced segmental sclerosis was present in 19.8% of glomeruli. Segmental sclerosis was present in 85% of biopsies. Significant mesangial hypercellularity, endocapillary proliferation, segmental sclerosis were present in, on average, 65, 22 and 85% of biopsies. Significant tubulointerstitial fibrosis (T1 or T2), >25%, was present in 33%. Tubulointerstitial fibrosis correlated with proteinuria and loss of eGFR over time, and endocapillary proliferation (E1) correlated with proteinuria over followup. Mesangial proliferation (M1) and segmental sclerosis/adhesion (S1) did not predict changes in eGFR or proteinuria in this cohort.
Conclusions: In conclusion, application of the Oxford IgAN classification to Chinese patients shows similar trends for prediction of clinical outcome in some, but not all variables, as the previous data set.
Category: Kidney (does not include tumors)
Wednesday, March 2, 2011 1:00 PM
Poster Session VI # 247, Wednesday Afternoon