title: Impact of patient volume on the mortality rate of adult intensive care unit patients.
abstract: OBJECTIVE
  Expert task forces have proposed that adult critical care medicine services should be regionalized in order to improve outcomes. However, it is currently unknown if high intensive care unit (ICU) patient volumes are associated with reduced mortality rate. The objective was to investigate whether high-volume ICUs have better mortality outcomes than low-volume ICUs.
  
  
  METHODS
  Retrospective cohort study analyzing the association between ICU volume and in-hospital mortality using Project IMPACT (a clinical outcomes database created by the Society of Critical Care Medicine).
  
  
  METHODS
  The analyses were based on 70,757 patients admitted to 92 ICUs between 2001 and 2003.
  
  
  METHODS
  None.
  
  
  RESULTS
  The main outcome measure was in-hospital mortality. Hierarchical logistic regression modeling was used to examine the volume-outcome association. The median (interquartile range) ICU volume was 827 (631-1,234) patient admissions per year. The overall mortality rate was 14.6%. After controlling for patient risk factors and ICU characteristics, and clustering, there was evidence that patients admitted to high-volume ICUs had improved outcomes (p = .025). However, this mortality benefit was seen only in high-risk patients treated at ICUs treating high volumes of high-risk patients.
  
  
  CONCLUSIONS
  There is evidence that high ICU patient volumes are associated with lower mortality rates in high-risk critically ill adults.
authors.affiliation: University of Rochester School of Medicine and Dentistry, USA.
authors.forename: Laurent G
authors.initials: LG
authors.lastname: Glance
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.forename: Turner M
authors.initials: TM
authors.lastname: Osler
authors.forename: Andrew
authors.initials: A
authors.lastname: Dick
authors.forename: Dana B
authors.initials: DB
authors.lastname: Mukamel
mesh_terms: D016638:Critical Illness / Q000401:mortality*; D005260:Female; D017052:Hospital Mortality / Q000639:trends*; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D014481:United States / Q000453:epidemiology; D016526:Workload