No apparent effect of the COVID-19 pandemic on out-of-hospital cardiac arrest incidence and outcome in Western Australia

Background: We examined the incidence, patient and arrest characteristics, and survival outcomes of out-of-hospital cardiac arrest (OHCA) in Western Australia (WA) in the first wave of the COVID-19 pandemic. Methods: Adult OHCA cases attended by St John WA Emergency Medical Service (EMS) between 16th March and 17th May 2020 (‘COVID-19 period’) were compared with those for the same period in 2017-9. We calculated crude OHCA incidence for all OHCA cases and modelled the effect of the ‘COVID-19 period’ on 30-day survival for OHCA cases with EMS attempted resuscitation; comparing our results with those published for Victoria (Australia), which had a higher incidence of COVID-19. Results: In WA there was no significant difference between the 2020 ‘COVID-19 period’ (n = 423) and the same period in 2017-9 (n = 1,334) in the OHCA incidence in adults (117.9 vs 126.1 per 100,000 person-years, p = 0.23). In OHCA cases with EMS-resuscitation attempted, there was no change in bystander cardiopulmonary resuscitation rates. Despite an increase in EMS response time, neither the crude nor risk-adjusted odds ratio (aOR) for 30-day survival in 2020 was significantly different to 2017-9 (11.7% vs 9.6%; p = 0.45) (aOR = 1.19, 95% confidence interval 0.57-2.51, p = 0.65). This contrasts with a significant reduction in survival to hospital discharge reported in Victoria. Conclusion: In WA, with a relatively low incidence of COVID-19, OHCA incidence and survival was not significantly different during the initial wave of the COVID-19 pandemic compared to the three previous years. Our study suggests that OHCA survival may be more closely related to the incidence of COVID-19 in the community, rather than COVID-19 restrictions per se.