title: Comparison of medical admissions to intensive care units in the United States and United Kingdom.
abstract: BACKGROUND
  The United States has seven times as many intensive care unit (ICU) beds per capita as the United Kingdom; the effect on care of critically ill patients is unknown.
  
  
  OBJECTIVE
  To compare medical ICU admissions in the United States and United Kingdom.
  
  
  METHODS
  Retrospective (2002-2004) cohort study of 172,785 ICU admissions (137 United States ICUs, Project IMPACT database; 160 United Kingdom ICUs, Case Mix Program) with patients followed until initial hospital discharge.
  
  
  RESULTS
  United Kingdom (vs. United States) admissions were less likely to be admitted directly from the emergency room (ER) (33.4% vs. 58%); had longer hospital stays before ICU admission (mean days 2.6 ± 8.2 vs. 1 ± 3.6); and fewer were greater than or equal to 85 years (3.2% vs. 7.8%). United Kingdom patients were more frequently mechanically ventilated within 24 hours after ICU admission (68% vs. 27.4%); were sicker (mean Acute Physiology Score 16.7 ± 7.6 vs. 10.6 ± 6.8); and had higher primary hospital mortality (38% vs. 15.9%; adjusted odds ratio, 1.73; 95% confidence interval, 1.50-1.99). There was no mortality difference for mechanically ventilated patients admitted from the ER (adjusted odds ratio, 1.09; 95% confidence interval, 0.89-1.33). Comparisons of hospital mortality were confounded by differences in case mix; hospital length of stay (United Kingdom median 10 d [interquartile range {IQR}, 3-24] vs. United States 6 d [IQR, 3-11]; and discharge practices (more United States patients were discharged to skilled care facilities [29% of survivors vs. 6% in the United Kingdom]).
  
  
  CONCLUSIONS
  Lower United Kingdom ICU bed availability is associated with fewer direct admissions from the ER, longer hospital stays before ICU admission, and higher severity of illness. Interpretation of between-country hospital outcomes is confounded by differences in case mix, processes of care, and discharge practices.
authors.affiliation: Department of Anesthesiology, Columbia University, New York, New York, USA.
authors.forename: Hannah
authors.initials: H
authors.lastname: Wunsch
authors.forename: Derek C
authors.initials: DC
authors.lastname: Angus
authors.forename: David A
authors.initials: DA
authors.lastname: Harrison
authors.forename: Walter T
authors.initials: WT
authors.lastname: Linde-Zwirble
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Rowan
mesh_terms: D000367:Age Factors; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009026:Mortality; D010343:Patient Admission / Q000706:statistics & numerical data; D005791:Patient Care / Q000592:standards; D012121:Respiration, Artificial; D012189:Retrospective Studies; D012720:Severity of Illness Index; D006113:United Kingdom; D014481:United States