Pathologic Predictors of Renal Outcome and Therapeutic Efficacy in IgA Nephropathy: Validation of the Oxford Classification

Background and objectives The Oxford classification of IgA nephropathy (IgAN) may aid in predicting prognosis and providing therapeutic strategy but must be validated in different ancestry. Design, setting, participants, & measurements A total of 410 patients with IgAN, enrolled from one of the largest renal centers in China, were evaluated for the predictive value of the Oxford classification to prognosis defined as end stage renal disease. A total of 294 of these patients were prospectively treated with renin-angiotensin system blockade and immunosuppressants sequentially and were evaluated separately to assess the predictive value to therapeutic efficacy (defined as time-averaged proteinuria <1 g/d). Three pathologists reviewed specimens independently according to the Oxford classification and were blinded to clinical data. Results Segmental glomerulosclerosis and tubular atrophy and interstitial fibrosis were independent predictive factors of end stage renal disease. Patients who had >25% of glomeruli with endocapillary hypercellularity showed higher proteinuria, lower estimated GFR, and higher mean BP than patients with less endocapillary hypercellularity. Immunosuppressive therapy showed a protective effect to prognosis of endocapillary hypercellularity in patients with endoncapillary hypercellularity could benefit from immunosuppressive therapy. Mesangial hypercellularity and tubular atrophy and interstitial fibrosis were independent factors of inefficiency of renin-angiotensin system blockade alone. Crescents were not significant in predicting prognosis or in therapeutic efficacy. Conclusions The Oxford classification may aid in predicting prognosis and providing a therapeutic strategy in Chinese patients with IgAN. Clin j Am Soc Nephrol 6: 2175-2184, 2011. doi:10.2215/CJN.11521210