title: Comparison of mortality prediction models after open abdominal aortic aneurysm repair.
abstract: OBJECTIVE
  Comparison of the accuracy of prediction of contemporary mortality prediction models after open Abdominal Aortic Aneurysm (AAA) surgery.
  
  
  METHODS
  Post-operative data were collected from AAA patients from 2 UK Intensive Care Units (ICU). POSSUM and VBHOM based models were compared to the APACHE-AAA model which was able to adjust for the hospital-related effect on outcome. Model performance was assessed using measures of calibration, discrimination and subgroup analysis.
  
  
  RESULTS
  541 patients were studied. The in-hospital mortality rate for elective AAA repair (325 patients) was: 6.2% (95% confidence interval (c.i.) 3.5 to 8.8) and for emergency repair (216 patients) was: 28.7% (95% c.i. 22.5-34.9). The APACHE-based model had the best overall fit to the whole population of AAA patients, and also separately in elective and emergency patients. The V-POSSUM physiology-only (p<0.001) and VBHOM (p=0.011) models had a poor fit in elective patients. The RAAA-POSSUM physiology-only (p<0.001) and VBHOM models (p=0.010) had a poor fit in emergency patients.
  
  
  CONCLUSIONS
  The APACHE-AAA model with its ability to adjust for both the hospital-related "effect" as well as the patient case-mix, was a more accurate risk stratification model than other contemporary models, in the post-operative AAA patient managed in ICU.
authors.affiliation: Department of Vascular Surgery, 1st Floor, North Wing, St. Thomas' Hospital, Lambeth Palace Road, London SE1 7EH. vassilis@doctors.org.uk
authors.forename: V G
authors.initials: VG
authors.lastname: Hadjianastassiou
authors.forename: P P
authors.initials: PP
authors.lastname: Tekkis
authors.forename: T
authors.initials: T
authors.lastname: Athanasiou
authors.forename: A
authors.initials: A
authors.lastname: Muktadir
authors.forename: J D
authors.initials: JD
authors.lastname: Young
authors.forename: L J
authors.initials: LJ
authors.lastname: Hands
mesh_terms: D018806:APACHE; D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000401:mortality* / Q000601:surgery*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011379:Prognosis; D018570:Risk Assessment; D012720:Severity of Illness Index; D016019:Survival Analysis; D014656:Vascular Surgical Procedures