title: Regional variation in out-of-hospital cardiac arrest incidence and outcome.
abstract: BACKGROUND
  The health and policy implications of regional variation in incidence and outcome of out-of-hospital cardiac arrest remain to be determined.
  
  
  OBJECTIVE
  To evaluate whether cardiac arrest incidence and outcome differ across geographic regions.
  
  
  METHODS
  Prospective observational study (the Resuscitation Outcomes Consortium) of all out-of-hospital cardiac arrests in 10 North American sites (8 US and 2 Canadian) from May 1, 2006, to April 30, 2007, followed up to hospital discharge, and including data available as of June 28, 2008. Cases (aged 0-108 years) were assessed by organized emergency medical services (EMS) personnel, did not have traumatic injury, and received attempts at external defibrillation or chest compressions or resuscitation was not attempted. Census data were used to determine rates adjusted for age and sex.
  
  
  METHODS
  Incidence rate, mortality rate, case-fatality rate, and survival to discharge for patients assessed or treated by EMS personnel or with an initial rhythm of ventricular fibrillation.
  
  
  RESULTS
  Among the 10 sites, the total catchment population was 21.4 million, and there were 20,520 cardiac arrests. A total of 11,898 (58.0%) had resuscitation attempted; 2729 (22.9% of treated) had initial rhythm of ventricular fibrillation or ventricular tachycardia or rhythms that were shockable by an automated external defibrillator; and 954 (4.6% of total) were discharged alive. The median incidence of EMS-treated cardiac arrest across sites was 52.1 (interquartile range [IQR], 48.0-70.1) per 100,000 population; survival ranged from 3.0% to 16.3%, with a median of 8.4% (IQR, 5.4%-10.4%). Median ventricular fibrillation incidence was 12.6 (IQR, 10.6-5.2) per 100,000 population; survival ranged from 7.7% to 39.9%, with a median of 22.0% (IQR, 15.0%-24.4%), with significant differences across sites for incidence and survival (P<.001).
  
  
  CONCLUSIONS
  In this study involving 10 geographic regions in North America, there were significant and important regional differences in out-of-hospital cardiac arrest incidence and outcome.
authors.affiliation: Department of Biostatistics, University of Washington Clinical Trial Center, Seattle, WA, USA. nichol@u.washington.edu
authors.forename: Graham
authors.initials: G
authors.lastname: Nichol
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Thomas
authors.forename: Clifton W
authors.initials: CW
authors.lastname: Callaway
authors.forename: Jerris
authors.initials: J
authors.lastname: Hedges
authors.forename: Judy L
authors.initials: JL
authors.lastname: Powell
authors.forename: Tom P
authors.initials: TP
authors.lastname: Aufderheide
authors.forename: Tom
authors.initials: T
authors.lastname: Rea
authors.forename: Robert
authors.initials: R
authors.lastname: Lowe
authors.forename: Todd
authors.initials: T
authors.lastname: Brown
authors.forename: John
authors.initials: J
authors.lastname: Dreyer
authors.forename: Dan
authors.initials: D
authors.lastname: Davis
authors.forename: Ahamed
authors.initials: A
authors.lastname: Idris
authors.forename: Ian
authors.initials: I
authors.lastname: Stiell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002170:Canada; D003710:Demography; D004632:Emergency Medical Services; D005260:Female; D006323:Heart Arrest / Q000150:complications / Q000453:epidemiology / Q000401:mortality* / Q000628:therapy*; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D012151:Resuscitation; D016019:Survival Analysis; D014481:United States; D014693:Ventricular Fibrillation / Q000150:complications