title: Regional incidence and outcome of out-of-hospital cardiac arrest associated with overdose.
abstract: BACKGROUND
  The frequency of lethal overdose due to prescription and non-prescription drugs is increasing in North America. The aim of this study was to estimate overall and regional variation in incidence and outcomes of out-of-hospital cardiac arrest due to overdose across North America.
  
  
  METHODS
  We conducted a retrospective cohort study using case data for the period 2006-2010 from the Resuscitation Outcomes Consortium, a clinical research network with 10 regional clinical centers in United States and Canada. Cases of out-of-hospital cardiac arrest due to drug overdose were identified through review of data derived from prehospital clinical records. We calculated incidence of out-of-hospital cardiac arrest due to overdose per 100,000 person-years and proportion of the same among all out-of-hospital cardiac arrests. We analyzed the association between overdose cardiac arrest etiology and resuscitation outcomes.
  
  
  RESULTS
  Included were 56,272 cases, of which 1351 were due to overdose. Regional incidence of out-of-hospital cardiac arrest due to overdose varied between 0.5 and 2.7 per 100,000 person years (p<0.001), and proportion of the same among all treated out-of-hospital cardiac arrests ranged from 0.8% to 4.0%. Overdose cases were younger, less likely to be witnessed, and less likely to present with a shockable rhythm. Compared to non-overdose, overdose was directly associated with return of spontaneous circulation (OR: 1.55; 95% CI: 1.35-1.78) and survival (OR: 2.14; 95% CI: 1.72-2.65).
  
  
  CONCLUSIONS
  Overdose made up 2.4% of all out-of-hospital cardiac arrest, although incidence varied up to 5-fold across regions. Overdose cases were more likely to survive than non-overdose cases.
authors.affiliation: University of Pittsburgh School of Medicine, Pittsburgh, PA, United States. Electronic address: salcidodd@upmc.edu.
authors.forename: David D
authors.initials: DD
authors.lastname: Salcido
authors.affiliation: University of Washington, Seattle, WA, United States.
authors.forename: Cesar
authors.initials: C
authors.lastname: Torres
authors.affiliation: University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
authors.forename: Allison C
authors.initials: AC
authors.lastname: Koller
authors.affiliation: University of Toronto, Toronto, Ontario, Canada.
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Orkin
authors.affiliation: University of Washington, Seattle, WA, United States.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Schmicker
authors.affiliation: University of Toronto, Toronto, Ontario, Canada.
authors.forename: Laurie J
authors.initials: LJ
authors.lastname: Morrison
authors.affiliation: University of Washington, Seattle, WA, United States.
authors.forename: Graham
authors.initials: G
authors.lastname: Nichol
authors.affiliation: University of Alabama, Birmingham, AL, United States.
authors.forename: Shannon
authors.initials: S
authors.lastname: Stephens
authors.affiliation: University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
authors.forename: James J
authors.initials: JJ
authors.lastname: Menegazzi
mesh_terms: D000328:Adult; D000368:Aged; D002170:Canada / Q000453:epidemiology; D016887:Cardiopulmonary Resuscitation; D015331:Cohort Studies; D062787:Drug Overdose / Q000150:complications*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D058687:Out-of-Hospital Cardiac Arrest / Q000139:chemically induced* / Q000453:epidemiology* / Q000628:therapy; D012189:Retrospective Studies; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology
keywords: Drug overdose; Epidemiology; Non-cardiac etiology