Association of socioeconomic status with 30-day survival following out-of-hospital cardiac arrest in Scotland, 2011-2020

BACKGROUND AND AIMS: The aim of this study was to investigate the crude and adjusted association of socioeconomic status with 30-day survival after out-of-hospital cardiac arrest (OHCA) in Scotland and to assess whether the effect of this association differs by sex or age.

METHODS: This is a population-based, retrospective cohort study, including non-traumatic, non-Emergency Medical Services witnessed patients with OHCA where resuscitation was attempted by the Scottish Ambulance Service, between April 1, 2011 and March 1, 2020. Socioeconomic status was defined using the Scottish Index of Multiple Deprivation (SIMD). The primary outcome was 30-day survival after OHCA. Crude and adjusted associations of SIMD quintile with 30-day survival after OHCA were estimated using logistic regression. Effect modification by age and sex was assessed by stratification.

RESULTS: Crude analysis showed lower odds of 30-day survival in the most deprived quintile relative to least deprived (OR 0.74, 95%CI 0.63-0.88). Adjustment for age, sex and urban/rural residency decreased the relative odds of survival further (OR 0.56, 95%CI 0.47-0.67). The strongest association was observed in males < 45 years old. Across quintiles of increasing deprivation, evidence of decreasing trends in the proportion of those presenting with shockable initial cardiac rhythm, those receiving bystander cardiopulmonary resuscitation and 30-day survival after OHCA were found.

CONCLUSIONS: Socioeconomic status is associated with 30-day survival after OHCA in Scotland, favouring people living in the least deprived areas. This was not explained by confounding due to age, sex or urban/rural residency. The strongest association was observed in males < 45 years old.