Epidemiology of pre-hospital outcomes of out-of-hospital cardiac arrest in Queensland, Australia

Objective: To describe incidence in pre-hospital outcomes of adult out-of-hospital cardiac arrest (OHCA) of presumed cardiac aetiology, attended by Queensland Ambulance Service (QAS) paramedics between 2002 and 2014, by age, gender, geographical remoteness and socio-economic status. Methods: The QAS OHCA Registry was used to identify cases, which was then linked with Queensland Hospital Admitted Patient Data Collection and Queensland Death Registry. Population data were obtained for each calendar year by age and gender from the Australian Bureau of Statistics in order to calculate incidence rates. Four mutually exclusive pre-hospital outcomes were analysed: (i) no resuscitation (No-Resus); (ii) resuscitation, no pre-hospital return of spontaneous circulation (No-ROSC); (iii) resuscitation, pre-hospital return of spontaneous circulation not sustained to hospital (Unsustained-ROSC); and (iv) resuscitation, pre-hospital return of spontaneous circulation sustained to hospital (Sustained-ROSC). Results: Over the 13 years, there were 30 560 OHCA cases for analyses. Incidence was significantly greater in males than females and incrementally increased with age, for each outcome. Incidence of total OHCA events generally increased as remoteness increased (major cities: 72.39 per 100 000 [95% CI 71.3573.45]; very remote: 87.01 per 100 000 [95% CI 78.03-95.98]). There was an inverse association between incidence of OHCA events and socio-economic status (SEIFA 1 and 2: 81.34 per 100 000 [95% CI 79.28-83.40]; SEIFA 9 and 10: 61.57 per 100 000 [95% CI 59.67-63.46]). Conclusion: Rural-specific strategies should be continued. Prevention and management strategies for OHCA targeting lower socio-economic groups require focus.