Effectiveness and Cost-Effectiveness of Automated External Defibrillators in Private Homes: A Report From the Cardiac Arrest Registry to Enhance Survival.

Importance: Automated external defibrillators (AEDs) have the potential to save lives when used during cardiac arrest. While most cardiac arrests occur at home, there is limited evidence for AED use in private homes. Objective: To determine whether AEDs in private homes are effective and cost-effective. Design, Setting, and Participants: This cohort study used observational data from the Cardiac Arrest Registry to Enhance Survival in the US from January 2017 to December 2024 to determine the effectiveness of AEDs when used for cardiac arrests in private homes. A difference-in-difference approach was used to determine the causal relationship between AED application and survival to hospital discharge. A decision-analytic model was then created to evaluate the cost-effectiveness of purchasing an AED in a private home in the US. Exposure: Application of an AED. Main Outcomes and Measures: Survival to hospital discharge and cost-effectiveness. Results: Of 582 536 included patients, 359 809 (61.8%) were male, and the median (IQR) age was 65 (52-76) years. Survival was better with AED application compared with no AED application in patients with a shockable rhythm (risk ratio, 1.26; 95% CI, 1.01-1.57) but not in those with a nonshockable rhythm (risk ratio, 1.00; 95% CI, 0.68-1.46). Results were consistent in the difference-in-difference analysis. The incremental cost-effectiveness ratio for an AED in a private home was $4 481 659 per quality-adjusted life-year. At a cost-effectiveness threshold of $200 000 per quality-adjusted life-year, AEDs in private homes would be considered cost-effective at a yearly cardiac arrest incidence per person above 1.3% or at an AED cost less than $65 (not including bystander training cost). Conclusions and Relevance: In this study, AEDs in private homes were effective at improving outcomes for patients with cardiac arrest and a shockable rhythm. Given the relative rarity of cardiac arrest at a given home, general purchase of AEDs for individual private homes cannot be considered cost-effective at the current pricing of AEDs.