Re-evaluation of the histopathologic classification of ANCA-associated glomerulonephritis: a study of 121 patients in a single center.

BACKGROUND The recently published histopathologic classification of antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis might greatly aid in the prognostication of patients at the time of diagnosis. This study aims to re-evaluate the new classification for its prognostic capacity in an independent Chinese series. METHODS One hundred and twenty-one consecutive patients with ANCA-associated glomerulonephritis, diagnosed in our center from 1997 to 2010, were included in this retrospective study. The renal specimens were reviewed according to the proposed histopathologic classification. The predictive value of the classification for renal outcome and renal response to treatment was analyzed. RESULTS Thirty-three (27.3%), 24 (19.8%), 53 (43.8%) and 11 (9.1%) patients were classified as focal, mixed, crescentic and sclerotic ANCA-associated glomerulonephritis, respectively. The renal biopsy categories correlated with initial serum creatinine and the renal response to treatment (P < 0.001, P < 0.01, respectively). The probability of progressing to end-stage renal disease (ESRD) increased with ascending categories of focal, mixed, crescentic and sclerotic glomerulonephritis (P < 0.01). The patients with focal, mixed and crescentic ANCA-associated glomerulonephritis were all at decreased risk for developing ESRD compared with the patients with in the sclerotic category (P < 0.05). CONCLUSIONS The proposed classification system was re-evaluated for the first time in a relatively large and independent series of patients. This system reflects the severity of the initial renal impairment and can predict, at least to some extent, the renal response to treatment. More importantly, it can independently predict renal outcome, in particular development of ESRD.