Socioeconomic disparities in Rapid ambulance response for out-of-hospital cardiac arrest in a public emergency medical service system: A nationwide observational study

Abstract

Objectives: This study aimed to examine whether county socioeconomic status (SES) is associated with emergency medical service (EMS) response time and dual dispatch response of out-of-hospital cardiac arrest (OHCA) patients using county property tax per capita in Korea.

Methods: All EMS-treated adults who suffered OHCAs were enrolled between 2015 and 2017, excluding cases witnessed by EMS providers. The main exposure was property tax per capita in the county where the OHCA occurred. The primary outcome was response time interval, with a secondary outcome of dual dispatch response. Negative binomial regression analysis to calculate incidence rate ratio (IRR) with a 95% confidence interval (CI) was conducted for EMS response time. A multivariable logistic regression analysis for response time interval (<8 min) and dual dispatch response was also conducted.

Results: A total of 71,326 patients in 228 counties were enrolled. Compared to the lowest SES quartile, OHCA patients in the highest SES quartile had shorter median (interquartile range [IQR]) response time intervals (9.5 [5.9] minutes vs. 7.6 [4.2] minutes, IRR [95% CI] 0.95 [0.94-0.96], respectively). The AOR (95% CI) for response time within 8 min was 1.07 (1.01-1.13) for the highest SES quartile compared to the lowest SES quartile. Those in the highest SES quartile also had higher rates of dual dispatch response compared to those in the lowest quantile (50.9% vs 26.6%; AOR [95% CI]: 2.16 [2.03-2.30]).

Conclusion: In OHCA patients, those in a lower SES are associated with longer response times and lower dual dispatch response.

Keywords: Emergency medical services; Out-of-Hospital cardiac arrest; Socioeconomic factors.