title: Location of cardiac arrest and impact of pre-arrest chronic disease and medication use on survival.
abstract: Cardiac arrest in a private location is associated with a higher mortality when compared to public location. Past studies have not accounted for pre-arrest factors such as chronic disease and medication.
  
  
  
  To investigate whether the association between cardiac arrest in a private location and a higher mortality can be explained by differences in chronic diseases and medication.
  
  
  
  We identified 27,771 out-of-hospital cardiac arrest patients ≥18 years old from the Danish Cardiac Arrest Registry (2001-2012). Using National Registries, we identified pre-arrest chronic disease and medication. To investigate the importance of cardiac arrest related factors and chronic disease and medication use we performed adjusted Cox regression analyses during day 0-7 and day 8-365 following cardiac arrest to calculate hazard ratios (HR) for death.
  
  
  
  Day 0-7: Un-adjusted HR for death day 0-7 was 1.21 (95%CI:1.18-1.25) in private compared to public location. When including cardiac arrest related factors HR for death was 1.09 (95%CI:1.06-1.12). Adding chronic disease and medication to the analysis changed HR for death to 1.08 (95%CI:1.05-1.12). 8-365 day: The un-adjusted HR for death day 8-365 was 1.70 (95% CI: 1.43-2.02) in private compared to public location. When including cardiac arrest related factors the HR decreased to 1.39 (95% CI: 1.14-1.68). Adding chronic disease and medication to the analysis changed HR for death to 1.27 (95% CI:1.04-1.54).
  
  
  
  The higher mortality following cardiac arrest in a private location is partly explained by a higher prevalence of chronic disease and medication use in patients surviving until day 8.
authors.affiliation: Department of Anesthesiology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: granfeldt@gmail.com.
authors.forename: Asger
authors.initials: A
authors.lastname: Granfeldt
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Denmark; Emergency Medical Services Copenhagen, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Mads
authors.initials: M
authors.lastname: Wissenberg
authors.affiliation: Department of Clinical Epidemiology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Steen Møller
authors.initials: SM
authors.lastname: Hansen
authors.affiliation: Emergency Medical Services Copenhagen, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Freddy K
authors.initials: FK
authors.lastname: Lippert
authors.affiliation: Department of Clinical Epidemiology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Torp-Pedersen
authors.affiliation: Prehospital Emergency Services, North Denmark Region, Aalborg, Denmark; Center for Prehospital and Emergency Research, Department of Clinical Medicine, Aalborg University, Aalborg, Denmark; Emergency Clinic, Department of Anaesthesiology and Intensive Care, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Erika Frischknecht
authors.initials: EF
authors.lastname: Christensen
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Christian Fynbo
authors.initials: CF
authors.lastname: Christiansen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016887:Cardiopulmonary Resuscitation; D002908:Chronic Disease / Q000453:epidemiology; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000150:complications / Q000401:mortality*; D011159:Population Surveillance; D016016:Proportional Hazards Models; D012042:Registries; D012307:Risk Factors; D013997:Time Factors
keywords: Cardiac arrest; Cardiopulmonary resuscitation; Chronic disease; Location; Medication use