ANCA Associated Vasculitis With AKI:Clinical Analysis

Objective:Kidney involvement is common in antineutrophil cytoplasmic antibody(ANCA)associated vasculitis.It tends to be aggressive,and may reach the criteria of acute kidney injury(AKI).Here we aim to analyze the clinical characteristics of these patients and risk factors for poor outcomes.Methods:Patients diagnosed with ANCA associated vasculitis and reached the criteria of AKI in our hospital from February 2003 to February 2017 were included.Clinical data including serum creatinine(Scr),Birmingham Vasculitis Activity Score(BVAS),age,gender,urine protein,etc.were retrieved through medical records.All patients were graded with KDIGO AKI criteria.According to the change of Scr level at 90 d,patients with AKI were further divided into 2 groups.Renal survival and all-cause mortality were analyzed.And patients diagnosed with ANCA associated vasculitis after November 2011 were further analyzed.Patients in the same period who didn't experience AKI were set as control.Serum and urine NGAL,IL-18,MCP-1 level as well as urine Dkk-3 level were detected through enzyme linked immunosorbent assay(ELISA),and compared.Results:During the median follow-up period of 64.0(IQR34.8,85.4)months,36(25.5%)patients reached renal endpoint,22(15.6%)patients did not survive.The median renal survival time was 35.9(IQR21.3,72.6)months and the median survival time was 48.4(IQR26.8,82.8)months.Multivariate analysis showed that poor recovery of Scr level at 90d(P<0.001,RR=6.1569,95%CI 2.920-12.977),high BVAS score(P=0.025,RR=1.099,95%CI1.012-1.193)and AKI stage 3(P=0.019,RR=2.892,95%CI1.194-7.007)were independent risk factor of renal endpoint;poor recovery of Scr level at 90d(P=0.013,RR=2.728,95%CI1.126-6.613),high BVAS score P=0.015,RR=1.159,95%CI1.029-1.306)and age(P=0.014,RR=1.048,95%CI1.010-1.087)were independent risk factor of death.When compared with non-AKI patients,those combined with AKI have higher serum NGAL level and the level of MCP-1 showed an upward trend but is not statistically significant.The level of serum IL-18 showed no statistical differences.And patients combined with AKI showed an increased urine NGAL,MCP-1,and dkk3 level.Conclusion:The level of serum NGAL level,and urine NGAL,MCP-1,Dkk3 is increased in ANCA patients with AKI.AKI stage is the risk factor of end stage renal disease(ESRD);the BVAS score and level of kidney function recovery at 90 days are the independent risk factor of ESRD and all-cause mortality.