Access to automated external defibrillators and first responders: Associations with socioeconomic factors and income inequality at small spatial scales.

Aim: The 2021 European Resuscitation Council (ERC) guidelines recommend two automated external defibrillators (AEDs)/km Method: We considered data on 776 AEDs in February 2022 and 1,173 out-of-hospital cardiac arrests (OHCAs) including 713 OHCA with app-alerted volunteer first responders from February to September 2022 in Berlin. We fit multilevel models to analyse AED area coverage and Poisson models to examine first responder availability across 12 districts and 536 neighbourhoods. Results: Median AED area coverage according to the 2021 ERC guidelines was 43.1% (interquartile range (IQR) 2.3-87.2) at the neighbourhood level and median number of available first responders per OHCA case was one (IQR 0.0-1.0). AED area coverage showed a positive association with average income tax per capita, with better coverage in the highest compared to the lowest quartile neighbourhoods (coefficient: 0.13, 95% confidence interval (CI): 0.01-0.25). First responder availability was not associated with income tax. AED area coverage and first responder availability were positively associated with income inequality, with better coverage (coefficient: 0.13, 95% CI: 0.04-0.23) and availability (rate ratio: 1.31, 95% CI: 1.03-1.67) in quartiles of highest as compared to lowest inequality. Conclusion: Access to resuscitation resources is neither equitable nor in accordance with the 2021 ERC guidelines. Ensuring better access necessitates understanding of socioeconomic factors and income inequality at small spatial scales.