Socioeconomic status and survival from out-of-hospital cardiac arrest

Background: Socioeconomic status (SES) has been linked to heart disease, but its influence on outcome from out-of-hospital cardiac arrest (OHCA) is not well understood. Objectives: The authors hypothesized that higher levels of SES would be associated with better survival, potentially through demographic, circumstance, or care factors. Methods: A cohort investigation of OHCA due to heart disease treated by emergency medical services between January 1, 1999, and December 31, 2003, was conducted in the study county. Socioeconomic status was assessed using two different measures: an individual-level measure, tax-assessed property value per unit, and a geography-based measure, median household income from the 2000 Census. The authors used logistic regression to evaluate the association between survival to hospital discharge and quartile of SES. Models systematically adjusted for demographic, circumstance, and care factors that could potentially confound the association. Results: Socioeconomic status as measured by value per unit was associated with survival in unadjusted models (odds ratio [OR] = 1.21; 95% confidence interval [95% CI] = 1.05 to 1.36, for each successive increase in value-per-unit quartile). Adjustment for demographic, circumstance, and care factors altered the association only slightly (fully adjusted OR = 1.23; 95% CI = 1.08 to 1.39). In contrast, SES as measured by median household income was not associated with survival. The study could not investigate all potentially explanatory factors. The findings may not be generalizable to persons or communities that differ from the current investigation. Conclusions: An individual-level, but not an area-level, measure of SES predicted survival following OHCA independent of demographic, circumstance, or care factors. Future research should continue to investigate mechanisms through which SES is associated with OHCA survival.