Association between distance to nearest automated external defibrillator and socioeconomic deprivation in Great Britain
Authors: Wilkinson C , Austin D , Wu J , Gale C P , Quinn T , Burgoine T 
Published: November 2023

Abstract

Background
Disparities in socioeconomic status manifest in death from out of hospital cardiac arrest (OHCA). Inequalities in access to automated external defibrillators (AED) due to socioeconomically determined location of AEDs may be associated with OHCA survival.

Purpose
To investigate distances between nearest AED location and postcode by socioeconomic deprivation for the population of Great Britain (GB).

Methods
AED location data for 2022 were drawn from the British Heart Foundation The Circuit registry. All 1,677,466 unit postcodes in Great Britain were linked to the Index of Deprivation for the corresponding Lower Layer Super Output Area using the 2019 Ministry of Housing Communities and Local Government tool. The median distance by road from the centre of each postcode to the nearest AED was calculated using geographic information systems. The proportion available 24/7 was also reported. Multilevel linear mixed regression models fit by country and adjusted for urban/rural status and clustering to calculate predicted marginal mean distances to the nearest active AED, and nearest AED accessible 24/7 by deprivation decile.

Results
78,425 unique AED locations were included in the analysis (Table 1). The median distance to nearest AED was 762.1m (IQR 410.8 - 1221.0) in GB; 742.7m (407.2 - 1340.7) in Scotland, 738.8m (422.6 - 1223.5) in England, and 511.5m (282.9 - 937.3) in Wales. For 24/7 access AEDs, median distances were greater: 964.0m (524.7 - 1667.5), 994.1m (538.5 – 1832.3), 990.8m (544.9 - 1683.3), and 569.7m (316.8 - 1033.4), respectively.
Overall, there was little evidence of a trend in nearest AED distance by deprivation (fig 1). In Scotland the nearest AED was, on average, 108m further away in the most compared with the least deprived areas. In England, the nearest AED was closer to postcodes in the least deprived areas of England (predicted mean 20m) and Wales (predicted mean 95m). In England, AEDs with 24/7 access were further from postcodes with increasing deprivation (predicted mean 99m further than least deprived areas). In Scotland, nearest 24/7 access AEDs were 317m further away in the most deprived areas, and 62m closer in Wales, but with no evidence of a linear trend.
At a typical walking speed (1.31m/sec), on average in GB it would take 17 minutes to retrieve an AED and 21 minutes out of hours. In England and Scotland out of hours, those in the most deprived areas would be delayed access to an AED by 2.5 and 8 minutes respectively compared the least deprived.

Conclusions
Overall, the median distance to nearest AED across postcodes in GB is at odds with the likelihood of successful resuscitation. Graded social inequalities were not observed in AED access across GB. However, substantive differences were observed in 24/7 AED access between most and least deprived areas of England and Scotland. Greater and more equitable access to AEDs has the potential to save lives and improve outcomes for people with OHCA.