ABSTRACT
Introduction: The coronavirus disease 2019 (COVID-19) pandemic has influenced epidemiology through direct and indirect effects, yet the impact on out-of-hospital cardiac arrest (OHCA) is unclear. We aimed to evaluate the impact of the pandemic on the incidence, characteristics, and clinical outcomes of OHCA. Hypothesis: We hypothesized that compared to the pre-pandemic period, the COVID-19 pandemic period was associated with increased incidence and case fatality rate (CFR) of OHCA, as well as decreased rates of intermediate clinical outcomes (termination of resuscitation [TOR], return of spontaneous circulation [ROSC], survival to hospital admission, and survival to hospital discharge). We further postulated that there was a change in the etiologies of OHCA during the pandemic as well as a decline in the rate of shockable rhythm as the initial presenting rhythm. Methods: In this systematic review and meta-analysis, five scientific databases were searched from inception to May 3, 2021. Meta-analyses were performed for the primary outcomes, secondary outcomes, and clinical characteristics. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42021253879). Results: The search yielded 966 articles. 20 articles were included for analysis. The COVID-19 pandemic was associated with a 39.5% increase in pooled annual OHCA incidence (p<0.001). Pooled CFR was increased by 2.65% (p<0.001), with an odds ratio (OR) of 1.95 for mortality (95% confidence interval [95%CI] 1.51-2.51). There was increased field TOR (OR=2.46, 95%CI 1.62- 3.74). There were decreased ROSC (OR=0.65, 95%CI 0.55-0.77), survival to hospital admission (OR=0.65, 95%CI 0.48-0.89), and survival to discharge (OR=0.52, 95%CI 0.40-0.69). There was decreased shockable rhythm (OR=0.73, 95%CI 0.60-0.88) and increased asphyxial etiology of OHCA (OR=1.17, 95%CI 1.02-1.33). There was moderate-to-high statistical heterogeneity. Findings were robust to sensitivity analyses, with no publication bias detected. Conclusions: The COVID-19 pandemic was associated with significant changes in OHCA epidemiology. Compared to the pre-pandemic period, the pandemic period was associated with increased OHCA incidence and worse outcomes.