Location of cardiac arrest and impact of pre-arrest chronic disease and medication use on survival

INTRODUCTION: 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.

AIM: 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.

METHODS: We identified 27,771 out-of-hospital cardiac arrest patients ≥18 years old from the Danish Cardiac Arrest Registry (20012012). 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.

RESULTS: 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).

CONCLUSION: The higher mortality following cardiac arrest in a private location is not fully explained by a higher prevalence of chronic disease and medication use in patients surviving until day 8.