Pre-hospital outcomes of adult out-of-hospital cardiac arrest of presumed cardiac aetiology in Queensland, Australia (2002-2014): Trends over time

Objective: To describe temporal trends in incidence of pre-hospital outcomes from 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: Cases included in this retrospective cohort study were identified from the QAS OHCA Registry. Included cases were linked with Queensland Hospital Admitted Patient Data Collection and Queensland Death Registry. Population data were obtained from the Australian Bureau of Statistics to calculate incidence rates for each year. Analyses were undertaken by four mutually exclusive pre-hospital outcomes: (i) no resuscitation (No-Resus); (ii) resuscitation, no pre-hospital return of spontaneous circulation (No-ROSC); (iii) resuscitation, prehospital return of spontaneous circulation not sustained to hospital (Unsustained-ROSC); and (iv) resuscitation, pre-hospital return of spontaneous circulation sustained to hospital (Sustained-ROSC). Trends over time were analysed for crude and specific rates for total OHCA events and for each outcome. Results: Between 2002 and 2014, there were 30 560 OHCA cases. Crude incidence significantly increased over time for No-Resus and Sustained-ROSC, and significantly decreased for No-ROSC. These trends were reflected in major cities, inner and outer regional areas. There was a significant increase in Sustained-ROSC in remote areas, and no significant trends in very remote areas. Conclusion: Incidence of with holding resuscitation and ROSC sustained to hospital have independently increased over time. Factors of middle age, more rural location and lower socio-economic status should all be targeted in the development and implementation of future strategies.