Pathological classification and prognosis of renal damage caused by antineutrophil cytoplasmic antibody associated vasculitis

Abstract

Objective To analyze the pathological characteristics and prognostic factors of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Methods A retrospective analysis of AAV patients with renal biopsy results admitted to Kidney Disease Center of the First Affiliated Hospital from January 2004 to February 2017 was performed. The patients were divided into 4 types according to Berden classification, and their clinical, pathological characteristics and prognosis were compared. The survival curves of each type of patients were plotted by Kaplan-Meier method, and the difference of survival curves was compared using Log-rank test. With entering the maintenance dialysis as the endpoint, Cox regression was used to analyze the prognostic factors. Results A total of 175 patients with AAV, including 59 cases (33.7%) of focal type, 39 cases (22.3%) of crescent type, 32 cases (18.3%) of sclerosis type, 45 cases (25.7%) of mixed type. The basal serum creatinine levels in crescent type group and sclerosis type group were significantly higher than those in the focal type group or mixed type group (all P<0.05), and loop necrosis rate in sclerosis type group was significantly lower than chat in the focal type group or crescent type group (both P<0.05). The median follow-up period was 11.8 (0.5-86.7) months. The event-free survival rates were 83.1%, 77.8%, 64.1% and 50.0% in the focal type, mixed type, crescent type and sclerotic type groups (Log-rank χ2=11.537, P=0.009). Cox regression analysis showed higher parathyroid hormone (HR=1.013, 95% CI 1.007-1.019, P<0.001), glomerular sclerosis ≥50% (HR=10.532, 95% CI 2.903-38.203, P<0.001) were independent risk factors for AAV patients entering maintenance dialysis, and higher estimated glomerular filtration rate (HR=0.943, 95% CI 0.896-0.993, P=0.025) was protective factor. Conclusion The prognosis of AAV renal damage is worsened according to focal, mixed, crescent and sclerosis types. Lower estimated glomerular filtration rate, higher parathyroid hormone and glomerular sclerosis ≥50% are independent risk factors for AAV patients entering maintenance dialysis. Key words: Antibodies, antineutrophil cytoplasmic; Vasculitis; Prognosis; Renal damage; Blood purification