title: Greater increase in urinary hepcidin predicts protection from acute kidney injury after cardiopulmonary bypass.
abstract: BACKGROUND
  Acute kidney injury (AKI) is a common and serious complication of cardiopulmonary bypass (CPB) surgery. Hepcidin, a peptide hormone that regulates iron homeostasis, is a potential biomarker of AKI following CPB.
  
  
  METHODS
  We investigated the association between post-operative changes in serum and urinary hepcidin and AKI in 93 patients undergoing CPB.
  
  
  RESULTS
  Twenty-five patients developed AKI based on the Risk, Injury, Failure, Loss, End-stage kidney disease (RIFLE) criteria in the first 5 days. Serum hepcidin, urine hepcidin concentration, the urinary hepcidin:creatinine ratio and fractional excretion of hepcidin in urine rose significantly after surgery. However, urine hepcidin concentration and urinary hepcidin:creatinine ratio were significantly lower at 24 h in patients with RIFLE-Risk, Injury or Failure compared to those without AKI (P = 0.0009 and P < 0.0001, respectively). Receiver operator characteristic analysis showed that lower 24-h urine hepcidin concentration and urinary hepcidin:creatinine ratio were sensitive and specific predictors of AKI. The urinary hepcidin:creatinine ratio had an area under the curve for the diagnosis of RIFLE ≥ risk at 24 h of 0.77 and of 0.84 for RIFLE ≥ injury. Urinary hepcidin had similar predictive accuracy. Such predictive ability remained when patients with early creatinine increases were excluded.
  
  
  CONCLUSIONS
  Urinary hepcidin and hepcidin:creatinine ratio are biomarkers of AKI after CPB, with an inverse association between its increase at 24 h and risk of AKI in the first five post-operative days. Measuring hepcidin in the urine on the first day following surgery may deliver earlier diagnosis and interventions.
authors.affiliation: Department of Intensive Care, Austin Hospital, Melbourne, Victoria, Australia.
authors.forename: John R
authors.initials: JR
authors.lastname: Prowle
authors.forename: Vaughn
authors.initials: V
authors.lastname: Ostland
authors.forename: Paolo
authors.initials: P
authors.lastname: Calzavacca
authors.forename: Elisa
authors.initials: E
authors.lastname: Licari
authors.forename: E Valentina
authors.initials: EV
authors.lastname: Ligabo
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Echeverri
authors.forename: Sean M
authors.initials: SM
authors.lastname: Bagshaw
authors.forename: Anja
authors.initials: A
authors.lastname: Haase-Fielitz
authors.forename: Michael
authors.initials: M
authors.lastname: Haase
authors.forename: Mark
authors.initials: M
authors.lastname: Westerman
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Bellomo
mesh_terms: D058186:Acute Kidney Injury / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality; D000368:Aged; D023181:Antimicrobial Cationic Peptides / Q000097:blood / Q000652:urine*; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015331:Cohort Studies; D001026:Coronary Artery Bypass / Q000009:adverse effects* / Q000379:methods; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D003404:Creatinine / Q000032:analysis / Q000378:metabolism; D017558:Elective Surgical Procedures / Q000009:adverse effects / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D064451:Hepcidins; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods; D011183:Postoperative Complications / Q000175:diagnosis / Q000401:mortality; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods; D012372:ROC Curve; D011859:Radiography; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome; D014739:Victoria
chemical_list: D023181:Antimicrobial Cationic Peptides; D015415:Biomarkers; C578702:HAMP protein, human; D064451:Hepcidins; D003404:Creatinine