Clinicopathologic predictors of death and ESRD in patients with pauci-immune necrotizing glomerulonephritis

Background: Pauci-immune necrotizing glomerulonephritis (PING) occurs in various settings and has a very variable prognosis. We investigated whether clinicopathologic findings at the time of renal biopsy may predict major disease outcomes. Methods: We evaluated 72 consecutive patients with biopsy-documented PING. Kaplan-Meier curves and Cox models assessed event rates and risk factors for death, end-stage renal disease (ESRD), and death or new ESRD (after the renal biopsy). Results: During a follow-up of 305 person-years, 11 patients died, 13 patients developed ESRD, and 16 patients died or developed new ESRD. Among patients first seen within 3 months of renal biopsy (incident cases), the 5-year mortality rate was 20%, whereas the death or new ESRD rate was 34%. In univariate analyses, older age, lower creatinine clearance, erythrocyte sedimentation rate, and percentages of abnormal glomeruli, glomeruli with fibrous crescents, and glomeruli with global sclerosis were significant predictors of mortality, whereas antineutrophil cytoplasmic autoantibodies with cytoplasmic staining conferred borderline protection. For ESRD, significant predictors included a greater creatinine level, lower hematocrit, interstitial fibrosis, tubular necrosis, greater C-reactive protein level, and percentages of abnormal glomeruli, glomeruli with extracapillary proliferation, cellular crescents, and global glomerulosclerosis. For death or new ESRD, predictors were fairly similar. Adjusting for baseline creatinine level, the risk for ESRD increased 1.78-fold (95% confidence interval [CI], 1.23 to 2.58) per each 10% increase in global sclerosis and 1.47-fold (95% CI, 1.05 to 2.07) per each 10% increase in glomeruli with cellular crescents. Conclusion: Global glomerulosclerosis and crescents in a renal biopsy are strong predictors of the long-term outcome of PING.