title: Evaluation of APACHE-IV Predictive Scoring in Surgical Abdominal Sepsis: A Retrospective Cohort Study.
abstract: BACKGROUND
  Evaluation of the effectiveness of care and clinical outcomes in critically ill patients is dependent on predictive scoring models that calculate measures of disease severity and an associated likelihood of mortality. The APACHE scoring system is a logistic regression model incorporating physiologic and laboratory parameters. APACHE-IV is the most updated scoring system for ICU mortality prediction. However, APACHE scores may not accurately predict mortality in patients who require surgery for abdominal sepsis, whose trajectory is modulated by source control procedures.
  
  
  OBJECTIVE
  To evaluate the accuracy of APACHE-IV mortality prediction in a cohort of ICU patients with surgical abdominal sepsis (SABS) requiring emergent laparotomy for source control.
  
  
  METHODS
  The study was conducted in a combined medical and surgical intensive care unit in a large urban Canadian tertiary care hospital. Retrospective review of 211 consecutive adult ICU admissions that fulfilled the 2012 ACCP/SCCM criteria for severe sepsis/septic shock due to abdominal source was performed. APACHE-IV score and predicted mortality rate (PMR) were calculated and evaluated using area under the ROC curve (AUROC).
  
  
  RESULTS
  Overall in-hospital mortality was 28.4%. There was overestimation of PMR by the APACHE-IV model in the overall cohort with an absolute difference of 16.6% (relative difference 36.9%). APACHE-IV crudely distinguished between survivors and non-survivors, with a PMR of 40% vs. 59% (p<0.001). AUROC of the APACHE-IV score was 0.67, 95% CI (0.58, 0.76) while the AUROC for the PMR was 0.72, 95% CI (0.64, 0.80), indicating poor performance in this cohort.
  
  
  CONCLUSIONS
  APACHE-IV has poor discrimination in SABS. Future research should explore disease-specific prediction models.
authors.affiliation: Resident, Department of General Surgery, University of British Columbia , Vancouver, Canada .
authors.forename: Tiffany
authors.initials: T
authors.lastname: Chan
authors.affiliation: Resident, Department of General Surgery, University of British Columbia , Vancouver, Canada .
authors.forename: Michael S
authors.initials: MS
authors.lastname: Bleszynski
authors.affiliation: Clinical Professor, Department of Surgery, Division of General Surgery, University of British Columbia , Vancouver, Canada .
authors.forename: Andrzej K
authors.initials: AK
authors.lastname: Buczkowski
keywords: Critical care; Infection; Outcomes; Prognostic scoring; Surgery