Risk Factors for Renal Survival in Chinese Patients with Myeloperoxidase-ANCA-Associated GN

Abstract

Background and objectives: Our study explored the association of histopathologic classification of ANCA-associated GN with renal survival in Chinese patients with myeloperoxidase-ANCA-associated GN.

Design, setting, participants, & measurements: Two hundred fifteen patients with biopsy-proven myeloperoxidase-ANCA-associated GN were included from January of 1996 to December of 2014. The biopsies included focal (n=27), mixed (n=82), crescentic (n=47), and sclerotic (n=59) classes. The long-term renal outcome and risk factors of myeloperoxidase-ANCA-associated GN for different histopathologic classes were retrospectively analyzed.

Results: During a median follow-up time of 22 (9-51) months, 88 (40.9%) patients reached ESRD. The 5-year renal survival (overall 58.7%) was highest in the focal class (100.0%) and lowest in the sclerotic class (20.7%), with no difference between the mixed (58.9%) and crescentic (67.4%) classes. Patients in the mixed (hazard ratio, 0.34; 95% confidence interval, 0.20 to 0.57; P<0.001) and crescentic (hazard ratio, 0.31; 95% confidence interval, 0.16 to 0.59; P<0.001) classes were at lower risk for ESRD compared with patients in the sclerotic class, as were patients who received glucocorticoids plus mycophenolate mofetil (hazard ratio, 0.32; 95% confidence interval, 0.18 to 0.60; P<0.001) compared with those receiving glucocorticoids alone. In addition, patients with a serum creatinine level ≥4 mg/dl (hazard ratio, 2.93; 95% confidence interval, 1.77 to 4.85; P<0.001) or hypoalbuminemia (hazard ratio, 2.11; 95% confidence interval, 1.32 to 3.34; P=0.002) were at higher risk for ESRD. A serum creatinine level ≥4 mg/dl and a percentage of global sclerotic glomeruli ≥60% were the two independent risk factors for ESRD in the sclerotic class.

Conclusions: The histopathologic classification of ANCA-associated GN in combination with serum creatinine and serum albumin levels and treatment regimen is associated with renal outcome in myeloperoxidase-ANCA-associated GN. The evaluation of serum creatinine level and percentage of global sclerotic glomeruli provides additional information on the risk of renal survival in the sclerotic class of myeloperoxidase-ANCA-associated GN.

Keywords: ANCA; Antibodies, Antineutrophil Cytoplasmic; Biopsy; Confidence Intervals; Follow-Up Studies; Glucocorticoids; Humans; Kidney Failure, Chronic; Kidney Glomerulus; Mycophenolic Acid; Neutrophils; Peroxidase; Retrospective Studies; Serum Albumin; glomerulonephritis; histopathology; hypoalbuminemia; kidney; mycophenolate mofetil; risk factors; vasculitis.

Figure 1.

Renal survival rates of myeloperoxidase-ANCA–associated GN in different risk factors. (A) histopathologic class, (B) serum creatinine (SCr) level, (C) serum albumin (S-Alb) level, and (D) treatment regimen. GC, glucocorticoid; IV-CTX, intravenous cyclophosphamide pulse therapy; MMF, mycophenolate mofetil.