title: The utility of the additive EuroSCORE, RIFLE and AKIN staging scores in the prediction and diagnosis of acute kidney injury after cardiac surgery.
abstract: OBJECTIVE
  Acute kidney injury (AKI) following cardiac surgery is a complication associated with high rates of morbidity and mortality. We compared staging systems for the diagnosis of AKI after cardiac surgery, and assessed pre-operative factors predictive of post-operative AKI.
  
  
  METHODS
  Clinical data, surgical risk scores, procedure and clinical outcome were obtained on all 4,651 patients undergoing cardiac surgery to the Royal Infirmary of Edinburgh between April 2006 and March 2011, of whom 4,572 had sufficient measurements of creatinine before and after surgery to permit inclusion and analysis. The presence of AKI was assessed using the AKIN and RIFLE criteria.
  
  
  RESULTS
  By AKIN criteria, 12.4% of the studied population developed AKI versus 6.5% by RIFLE criteria. Any post-operation AKI was associated with increased mortality from 2.2 to 13.5% (relative risk 7.0, p < 0.001), and increased inpatient stay from a median of 7 (IQR 4) to 9 (IQR 11) days (p < 0.05). Patients identified by AKIN, but not RIFLE, had a mean peak creatinine rise of 34% from baseline and had a significantly lower mortality compared to RIFLE-'Risk' AKI (mortality 6.1 vs. 9.7%; p < 0.05). Pre-operative creatinine, diabetes, NYHA Class IV dyspnoea and EuroSCORE-1 (a surgical risk score) all predicted subsequent AKI on multivariate analysis. EuroSCORE-1 outperformed any single demographic factor in predicting post-operative AKI risk, equating to an 8% increase in relative risk for each additional point.
  
  
  CONCLUSIONS
  AKI after cardiac surgery is associated with delayed discharge and high mortality rates. The AKIN and RIFLE criteria identify patients at a range of AKI severity levels suitable for trial recruitment. The utility of EuroSCORE as a risk stratification tool to identify high AKI-risk subjects for prospective intervention merits further study.
authors.affiliation: MRC Centre for Inflammation Research, Queen's Medical Research Institute, Edinburgh, UK.
authors.forename: Fiona A I
authors.initials: FA
authors.lastname: Duthie
authors.forename: Paul
authors.initials: P
authors.lastname: McGeehan
authors.forename: Sharleen
authors.initials: S
authors.lastname: Hill
authors.forename: Richard
authors.initials: R
authors.lastname: Phelps
authors.forename: David C
authors.initials: DC
authors.lastname: Kluth
authors.forename: Vipin
authors.initials: V
authors.lastname: Zamvar
authors.forename: Jeremy
authors.initials: J
authors.lastname: Hughes
authors.forename: David A
authors.initials: DA
authors.lastname: Ferenbach
mesh_terms: D058186:Acute Kidney Injury / Q000175:diagnosis* / Q000209:etiology*; D000368:Aged; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D012306:Risk; D012720:Severity of Illness Index