Clinicopathologic characteristics and outcomes of renal thrombotic microangiopathy in anti-neutrophil cytoplasmic autoantibody-associated glomerulonephritis.
OBJECTIVE
Thrombotic microangiopathy (TMA) in ANCA-associated vasculitis (AAV) has been mainly reported in isolated case reports. The aim of this study was to analyze clinical and pathologic characteristics and prognosis of patients with renal TMA in ANCA-associated GN in a large cohort of Chinese patients.


METHODS
Clinical and renal histopathologic data of 220 patients with biopsy-proven ANCA-associated GN from 1996 to 2013 were retrospectively analyzed. Patients were followed up for a median period of 32 (interquartile range [IQR], 12-65) months, and outcomes of patients were analyzed.


RESULTS
Among the 220 patients with ANCA-associated GN, 30 were identified having concomitant renal TMA by pathologic evaluation. Compared with the non-TMA group, patients with renal TMA presented with more severe renal injury, as evidenced clinically by a higher level of serum creatinine at diagnosis (5.0 [IQR, 3.5-9.0] versus 3.2 [IQR, 1.7-6.8] mg/dl; P=0.02) and pathologically by a higher percentage of cellular crescents (15.0% [IQR, 6.9%-34.9%] versus 6.9% [IQR, 0%-21.1%]; P=0.04) and more severe interstitial infiltration (2 [IQR, 2-2] versus 2 [IQR, 1-2]; P=0.03) in renal biopsies. Furthermore, multivariate analysis showed that renal TMA was independently associated with mortality of patients with AAV after adjusting for age, sex, initial serum creatinine, tubular atrophy, and interstitial fibrosis (hazard ratio, 1.92; 95% confidence interval, 1.08 to 3.41; P=0.03) or for age, sex, the histopathologic classification scheme proposed by Berden et al. (J Am Soc Nephrol 21: 1628-1636, 2010), tubular atrophy, and interstitial fibrosis (hazard ratio, 1.95; 95% confidence interval, 1.07 to 3.55; P=0.03).


CONCLUSIONS
Renal TMA in ANCA-associated GN is not rare and presents with more severe renal injury. Renal TMA is independently associated with all-cause mortality in patients with AAV.
Renal Division, Department of Medicine, Peking University, First Hospital, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, China; and.
Su-Fang
SF
Chen
Renal Division, Department of Medicine, Peking University, First Hospital, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, China; and.
Huan
H
Wang
Renal Division, Department of Medicine, Peking University, First Hospital, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, China; and.
Yi-Min
YM
Huang
Renal Division, Department of Medicine, Peking University, First Hospital, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, China; and.
Zhi-Ying
ZY
Li
Renal Division, Department of Medicine, Peking University, First Hospital, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, China; and.
Su-Xia
SX
Wang
Renal Division, Department of Medicine, Peking University, First Hospital, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, China; and.
Feng
F
Yu
Renal Division, Department of Medicine, Peking University, First Hospital, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, China; and Peking-Tsinghua Center for Life Sciences, Beijing, China.
Ming-Hui
MH
Zhao
Renal Division, Department of Medicine, Peking University, First Hospital, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing, China; and chenmin74@sina.com.
Min
M
Chen
D051722:ADAM Proteins / Q000097:blood; D000071120:ADAMTS13 Protein; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000150:complications / Q000401:mortality; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000032:analysis; D001379:Azathioprine / Q000627:therapeutic use; D003404:Creatinine / Q000097:blood; D003520:Cyclophosphamide / Q000627:therapeutic use; D005260:Female; D005921:Glomerulonephritis / Q000150:complications* / Q000188:drug therapy / Q000276:immunology / Q000473:pathology*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008297:Male; D008775:Methylprednisolone / Q000627:therapeutic use; D008875:Middle Aged; D011379:Prognosis; D012008:Recurrence; D012189:Retrospective Studies; D012720:Severity of Illness Index; D015996:Survival Rate; D057049:Thrombotic Microangiopathies / Q000150:complications* / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D016896:Treatment Outcome
D000305:Adrenal Cortex Hormones; D000893:Anti-Inflammatory Agents; D019268:Antibodies, Antineutrophil Cytoplasmic; D006454:Hemoglobins; D007166:Immunosuppressive Agents; D003520:Cyclophosphamide; D003404:Creatinine; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human; D001379:Azathioprine; D008775:Methylprednisolone
ANCA; outcomes; thrombosis; vasculitis