title: Urinary angiotensinogen and risk of severe AKI.
abstract: BACKGROUND
  Biomarkers of AKI that can predict which patients will develop severe renal disease at the time of diagnosis will facilitate timely intervention in populations at risk of adverse outcomes.
  
  
  METHODS
  Liquid chromatography/tandem mass spectrometry was used to identify 30 potential prognostic urinary biomarkers of severe AKI in a group of patients that developed AKI after cardiac surgery. Angiotensinogen had the best discriminative characteristics. Urinary angiotensinogen was subsequently measured by ELISA and its prognostic predictive power was verified in 97 patients who underwent cardiac surgery between August 1, 2008 and October 6, 2011.
  
  
  RESULTS
  The urine angiotensinogen/creatinine ratio (uAnCR) predicted worsening of AKI, Acute Kidney Injury Network (AKIN) stage 3, need for renal replacement therapy, discharge >7 days from sample collection, and composite outcomes of AKIN stage 2 or 3, AKIN stage 3 or death, and renal replacement therapy or death. The prognostic predictive power of uAnCR was improved when only patients classified as AKIN stage 1 at the time of urine sample collection (n=79) were used in the analysis, among whom it predicted development of stage 3 AKI or death with an area under the curve of 0.81. Finally, category free net reclassification improvement showed that the addition of uAnCR to a clinical model to predict worsening of AKI improved the predictive power.
  
  
  CONCLUSIONS
  Elevated uAnCR is associated with adverse outcomes in patients with AKI. These data are the first to demonstrate the utility of angiotensinogen as a prognostic biomarker of AKI after cardiac surgery.
authors.affiliation: Medical University of South Carolina, Charleston, SC 29425, USA.
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Alge
authors.forename: Nithin
authors.initials: N
authors.lastname: Karakala
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Neely
authors.forename: Michael G
authors.initials: MG
authors.lastname: Janech
authors.forename: James A
authors.initials: JA
authors.lastname: Tumlin
authors.forename: Lakhmir S
authors.initials: LS
authors.lastname: Chawla
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Shaw
authors.forename: John M
authors.initials: JM
authors.lastname: Arthur
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology / Q000652:urine*; D000368:Aged; D000808:Angiotensinogen / Q000652:urine*; D015415:Biomarkers / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012306:Risk; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D000808:Angiotensinogen