title: A risk score for predicting 30-day mortality in heart failure patients undergoing non-cardiac surgery.
abstract: BACKGROUND
  Heart failure is an established risk factor for poor outcomes in patients undergoing non-cardiac surgery, yet risk stratification remains a clinical challenge. We developed an index for 30-day mortality risk prediction in this particular group.
  
  
  RESULTS
  All individuals with heart failure undergoing non-cardiac surgery between October 23 2004 and October 31 2011 were included from Danish administrative registers (n = 16 827). In total, 1787 (10.6%) died within 30 days. In a simple risk score based on the variables from the revised cardiac risk index, plus age, gender, acute surgery, and body mass index category the following variables predicted mortality (points): male gender (1), age 56-65 years (2), age 66-75 years (4), age 76-85 years (5), or age >85 years (7), being underweight (4), normal weight (3), or overweight (1), undergoing acute surgery (5), undergoing high-risk procedures (intra-thoracic, intra-abdominal, or suprainguinal aortic) (3), having renal disease (1), cerebrovascular disease (1), and use of insulin (1). The c-statistic was 0.79 and calibration was good. Mortality risk ranged from <2% for a score <5 to >50% for a score ≥20. Internal validation by bootstrapping (1000 re-samples) provided c-statistic of 0.79. A more complex risk score based on stepwise logistic regression including 24 variables at P < 0.05 performed only slightly better, c-statistic = 0.81, but was limited in use by its complexity.
  
  
  CONCLUSIONS
  For patients with heart failure, this simple index can accurately identify those at low risk for perioperative mortality.
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Gentofte, Niels Andersens vej 65, DK-2900, Hellerup, Denmark.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Andersson
authors.forename: Gunnar H
authors.initials: GH
authors.lastname: Gislason
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hlatky
authors.forename: Kathrine Bach
authors.initials: KB
authors.lastname: Søndergaard
authors.forename: Jannik
authors.initials: J
authors.lastname: Pallisgaard
authors.forename: J Gustav
authors.initials: JG
authors.lastname: Smith
authors.forename: Ramachandran S
authors.initials: RS
authors.lastname: Vasan
authors.forename: Martin G
authors.initials: MG
authors.lastname: Larson
authors.forename: Per Føge
authors.initials: PF
authors.lastname: Jensen
authors.forename: Lars
authors.initials: L
authors.lastname: Køber
authors.forename: Christian
authors.initials: C
authors.lastname: Torp-Pedersen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006305:Health Status Indicators; D006333:Heart Failure / Q000401:mortality* / Q000601:surgery*; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D059035:Perioperative Period / Q000401:mortality; D018570:Risk Assessment; D012307:Risk Factors; D013514:Surgical Procedures, Operative / Q000401:mortality*
keywords: Heart failure; Mortality; Non-cardiac surgery; Risk factors; Risk prediction