title: Intensive Care Society's APACHE II study in Britain and Ireland--I: Variations in case mix of adult admissions to general intensive care units and impact on outcome.
abstract: OBJECTIVE
  To describe the extent of variation in the case mix of adult admissions to general intensive care units in Britain and Ireland and investigate the impact of such variation on outcome.
  
  
  METHODS
  Prospective, cohort study of consecutive admissions to intensive care units.
  
  
  METHODS
  26 general intensive care units in Britain and Ireland.
  
  
  METHODS
  9099 admissions to the intensive care units studied.
  
  
  METHODS
  Death or survival at discharge before and after adjustment of case mix (age, history of chronic conditions, surgical status, diagnosis, and severity of illness) according to the APACHE II method.
  
  
  RESULTS
  Important differences in case mix were found, with large variations between the units. Hospital mortality was significantly associated with most of the case mix factors investigated.
  
  
  CONCLUSIONS
  Comparing crude death rates in hospital between intensive care units may be misleading indicators of performance. The collection of data on case mix needs to be standardised and differences in case mix adjusted for when comparing outcome between different intensive care units.
authors.affiliation: Department of Public Health and Primary Care, University of Oxford, Radcliffe Infirmary.
authors.forename: K M
authors.initials: KM
authors.lastname: Rowan
authors.forename: J H
authors.initials: JH
authors.lastname: Kerr
authors.forename: E
authors.initials: E
authors.lastname: Major
authors.forename: K
authors.initials: K
authors.lastname: McPherson
authors.forename: A
authors.initials: A
authors.lastname: Short
authors.forename: M P
authors.initials: MP
authors.lastname: Vessey
mesh_terms: D000367:Age Factors; D015331:Cohort Studies; D003953:Diagnosis-Related Groups / Q000145:classification; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units / Q000592:standards / Q000706:statistics & numerical data*; D007494:Ireland / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010343:Patient Admission / Q000706:statistics & numerical data*; D011446:Prospective Studies; D012720:Severity of Illness Index; D006113:United Kingdom / Q000453:epidemiology