title: The level of the biomarkers at the time of nephrology consultation might predict the prognosis of acute kidney injury in hospitalized patients.
abstract: BACKGROUND
  The value of biomarkers at the time of nephrology consultation in predicting the prognosis of acute kidney injury (AKI) in hospitalized patients has not been well described. This study aimed to evaluate the possibility of biomarkers at the time of nephrology consultation in predicting the prognosis of AKI.
  
  
  METHODS
  We prospectively enrolled 103 hospitalized patients who developed AKI. Urinary Neutrophil Gelatinase Associated Lipocalin (NGAL), IL-6, IL-18, N-Acetyl-β-D-Glucosaminidase (NAG), and serum Cystatin C (CysC) were measured at the time of nephrology consultation. Baseline values of serum creatinine (bScr), serum creatinine on consultation (cScr) and the peak level of serum creatinine (pScr) were recorded. All the patients were followed-up till 28 days since consultation. Serum and urinary levels of the biomarkers were compared according to the patient or kidney prognosis. Each marker was assessed for its predictive value using receiver operator characteristic (ROC) curves to predict AKI prognosis.
  
  
  RESULTS
  Patients were aged 54.28 ± 19.05. Male patients constituted 65% of the study group and baseline Scr was 93.54 ± 35.98 μmol/l. The mortality rate of the patients was 25.2% and kidney loss rate was 18.8% at 28 days after consultation. The level of urinary NGAL was significantly higher in death patients than that in survival patients [147.00 (31.59, 221.87) μg/ml vs. 22.43 (6.48, 89.77) μg/ml, p = 0.001], while the level of bScr, cScr, pScr, urinary IL-6 and NAG were similar in both these groups. The AUC of urinary NGAL for predicting patients' death was 0.723 (p = 0.001). Serum CysC and urinary IL-18 concentration was higher in the death patients with a marginal p value (p = 0.065 and 0.059 respectively). All the urinary markers, including NAG, NGAL, IL-6 and IL-18 were significantly higher in patients with kidney loss than in those with kidney survival, while no difference was found in Scr and serum CysC levels. The AUCs of these urinary biomarkers for predicting kidney survival were 0.663, 0.655, 0.705 and 0.663 respectively (p < 0.05). The concentrations of cScr, pScr, serum CysC, urinary IL-6 and NGAL were significantly higher in RRT patients (p < 0.05). The AUCs for predicting RRT were 0.628, 0.781, 0.768, 0.672 and 0.775 respectively.
  
  
  CONCLUSIONS
  The level of biomarkers at the time of nephrology consultation might predict the prognosis of AKI in hospitalized patients. Further studies should be done to understand the role of the serum and urinary markers in the prognosis of AKI.
authors.affiliation: Department of Nephrology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Renhua
authors.forename: Che
authors.initials: C
authors.lastname: Miaolin
authors.forename: Wang
authors.initials: W
authors.lastname: Junlin
authors.forename: Wu
authors.initials: W
authors.lastname: Qingwei
authors.forename: Xu
authors.initials: X
authors.lastname: Xiaoping
authors.forename: Dai
authors.initials: D
authors.lastname: Huili
authors.forename: Zhang
authors.initials: Z
authors.lastname: Weiming
authors.forename: Ni
authors.initials: N
authors.lastname: Zhaohui
authors.forename: Qian
authors.initials: Q
authors.lastname: Jiaqi
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Yan
mesh_terms: D000118:Acetylglucosaminidase / Q000652:urine*; D058186:Acute Kidney Injury / Q000097:blood / Q000175:diagnosis* / Q000401:mortality / Q000652:urine; D000209:Acute-Phase Proteins / Q000652:urine*; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000652:urine; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood*; D005260:Female; D006801:Humans; D007297:Inpatients; D020382:Interleukin-18 / Q000652:urine*; D015850:Interleukin-6 / Q000652:urine*; D000071068:Lipocalin-2; D054834:Lipocalins / Q000652:urine*; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000652:urine*; D011379:Prognosis; D011446:Prospective Studies; D011518:Proto-Oncogene Proteins / Q000652:urine*; D012372:ROC Curve; D012017:Referral and Consultation; D016019:Survival Analysis
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; C000589760:IL18 protein, human; C508600:IL6 protein, human; D020382:Interleukin-18; D015850:Interleukin-6; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; C117339:NBAS protein, human; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D003404:Creatinine; D000118:Acetylglucosaminidase