A disparity in outcomes of out-of-hospital cardiac arrest by community socioeconomic status: A ten-year observational study

Background: The objective of this study was to compare the temporal trends in good neurologic outcome after out-of-hospital cardiac arrest (OHCA) between communities with different socioeconomic status (SES). Methods: A nationwide, population-based observational study was conducted in adult patients with OHCA of cardiac etiology from 2006 to 2015. Community SES was defined using the Carstairs index categorized into 5 groups, from Q1 (the least deprived) to Q5 (the most deprived). Outcomes included good neurologic outcome, survival to hospital discharge and rate of bystander cardiopulmonary resuscitation (CPR). Using multivariable logistic regression, we examined temporal trends in risk-adjusted outcome rates according to community SES and estimated a difference-in-differences model between 2006 and 2015 to compare the changes over time in communities with different SES. Results: A total of 120,365 OHCAs met inclusion criteria. Risk-adjusted rates increased from 2006 to 2015 for bystander CPR (1.2%-23.2%), survival to discharge (3.0%-8.0%), and good neurological outcome (0.9%-5.8%). However, the degree of improvement in each risk-adjusted rate among SES groups were different. The communities with highest SES showed much greater improvement (bystander CPR 1.6%-34.6%; survival to discharge 3.5%-9.9%; and good neurological outcome 1.6%-7.4%) while less improvement in lower SES communities (1.6%-15.5%; 2.3%-6.2%; and 0.5%-4.2%, respectively). For rates of bystander CPR, the adjusted difference-in-differences value was statistically significant in highest SES communities, showing gradient from 11.48% increase in the lowest SES to 22.39% increase in the highest SES. Conclusion: In Korea, both survival to hospital discharge and good neurologic outcomes after OHCA have improved during the past decade. However, disparity in outcomes was observed based on community socioeconomic status. Outcome improvements were greatest in communities with higher SES but relatively less in lower SES communities.