title: The effect of emergency department crowding on clinically oriented outcomes.
abstract: BACKGROUND
  An Institute of Medicine (IOM) report defines six domains of quality of care: safety, patient-centeredness, timeliness, efficiency, effectiveness, and equity. The effect of emergency department (ED) crowding on these domains of quality has not been comprehensively evaluated.
  
  
  OBJECTIVE
  The objective was to review the medical literature addressing the effects of ED crowding on clinically oriented outcomes (COOs).
  
  
  METHODS
  We reviewed the English-language literature for the years 1989-2007 for case series, cohort studies, and clinical trials addressing crowding's effects on COOs. Keywords searched included "ED crowding,""ED overcrowding,""mortality,""time to treatment,""patient satisfaction,""quality of care," and others.
  
  
  RESULTS
  A total of 369 articles were identified, of which 41 were kept for inclusion. Study quality was modest; most articles reflected observational work performed at a single institution. There were no randomized controlled trials. ED crowding is associated with an increased risk of in-hospital mortality, longer times to treatment for patients with pneumonia or acute pain, and a higher probability of leaving the ED against medical advice or without being seen. Crowding is not associated with delays in reperfusion for patients with ST-elevation myocardial infarction. Insufficient data were available to draw conclusions on crowding's effects on patient satisfaction and other quality endpoints.
  
  
  CONCLUSIONS
  A growing body of data suggests that ED crowding is associated both with objective clinical endpoints, such as mortality, as well as clinically important processes of care, such as time to treatment for patients with time-sensitive conditions such as pneumonia. At least two domains of quality of care, safety and timeliness, are compromised by ED crowding.
authors.affiliation: Department of Emergency Medicine, Albert Einstein College of Medicine, Bronx, NY, USA. sbernste@montefiore.org
authors.forename: Steven L
authors.initials: SL
authors.lastname: Bernstein
authors.forename: Dominik
authors.initials: D
authors.lastname: Aronsky
authors.forename: Reena
authors.initials: R
authors.lastname: Duseja
authors.forename: Stephen
authors.initials: S
authors.lastname: Epstein
authors.forename: Dan
authors.initials: D
authors.lastname: Handel
authors.forename: Ula
authors.initials: U
authors.lastname: Hwang
authors.forename: Melissa
authors.initials: M
authors.lastname: McCarthy
authors.forename: K
authors.initials: K
authors.lastname: John McConnell
authors.forename: Jesse M
authors.initials: JM
authors.lastname: Pines
authors.forename: Niels
authors.initials: N
authors.lastname: Rathlev
authors.forename: Robert
authors.initials: R
authors.lastname: Schafermeyer
authors.forename: Frank
authors.initials: F
authors.lastname: Zwemer
authors.forename: Michael
authors.initials: M
authors.lastname: Schull
authors.forename: Brent R
authors.initials: BR
authors.lastname: Asplin
mesh_terms: D000700:Analgesics / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015331:Cohort Studies; D003441:Crowding; D004636:Emergency Service, Hospital / Q000458:organization & administration* / Q000592:standards; D006297:Health Services Accessibility; D017052:Hospital Mortality; D006801:Humans; D009203:Myocardial Infarction / Q000628:therapy; D011014:Pneumonia / Q000188:drug therapy; D011787:Quality of Health Care; D015912:Thrombolytic Therapy; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000700:Analgesics; D000900:Anti-Bacterial Agents