title: Does location matter? A proposed methodology to evaluate neighbourhood effects on cardiac arrest survival and bystander CPR.
abstract: BACKGROUND
  Traditional variables used to explain survival following out-of-hospital cardiac arrest (OHCA) account for only 72% of survival, suggesting that other unknown factors may influence outcomes. Research on other diseases suggests that neighbourhood factors may partly determine health outcomes. Yet, this approach has rarely been used for OHCA. This work outlines a methodology to investigate multiple neighbourhood factors as determinants of OHCA outcomes.
  
  
  METHODS
  A retrospective, observational cohort study design will be used. All adult non-emergency medical service witnessed OHCAs of cardiac etiology within the city of Toronto between 2006 and 2010 will be included. Event details will be extracted from the Toronto site of the Resuscitation Outcomes Consortium Epistry-Cardiac Arrest, an existing population-based dataset of consecutive OHCA patients. Geographic information systems technology will be used to assign patients to census tracts. Neighbourhood variables to be explored include the Ontario Marginalization Index (deprivation, dependency, ethnicity, and instability), crime rate, and density of family physicians. Hierarchical logistic regression analysis will be used to explore the association between neighbourhood characteristics and 1) survival-to-hospital discharge, 2) return-of-spontaneous circulation at hospital arrival, and 3) provision of bystander cardiopulmonary resuscitation (CPR). Receiver operating characteristics curves will evaluate each model's ability to discriminate between those with and without each outcome. Discussion This study will determine the role of neighbourhood characteristics in OHCA and their association with clinical outcomes. The results can be used as the basis to focus on specific neighbourhoods for facilitating educational interventions, CPR awareness programs, and higher utilization of automatic defibrillation devices.
authors.affiliation: *Rescu,Li Ka Shing Knowledge Institute,St. Michael's Hospital,Toronto,ON.
authors.forename: Jason E
authors.initials: JE
authors.lastname: Buick
authors.affiliation: ‡Institute of Medical Science, Faculty of Medicine,University of Toronto,ON.
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Allan
authors.affiliation: †Institute of Health Policy,Management and Evaluation, Faculty of Medicine,University of Toronto,ON.
authors.forename: Joel G
authors.initials: JG
authors.lastname: Ray
authors.affiliation: †Institute of Health Policy,Management and Evaluation, Faculty of Medicine,University of Toronto,ON.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kiss
authors.affiliation: *Rescu,Li Ka Shing Knowledge Institute,St. Michael's Hospital,Toronto,ON.
authors.forename: Paul
authors.initials: P
authors.lastname: Dorian
authors.affiliation: ¶Li Ka Shing Knowledge Institute,St. Michael's Hospital,Toronto,ON.
authors.forename: Peter
authors.initials: P
authors.lastname: Gozdyra
authors.affiliation: *Rescu,Li Ka Shing Knowledge Institute,St. Michael's Hospital,Toronto,ON.
authors.forename: Laurie J
authors.initials: LJ
authors.lastname: Morrison
mesh_terms: D000328:Adult; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D004632:Emergency Medical Services / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009864:Ontario; D058687:Out-of-Hospital Cardiac Arrest / Q000628:therapy*; D010351:Patient Discharge; D012042:Registries; D012189:Retrospective Studies; D013997:Time Factors
keywords: cardiopulmonary resuscitation; emergency medical services; geographic information systems; out-of-hospital cardiac arrest; residence characteristics