Trends in Sudden Unexpected Deaths in an Australian Population: Impact of the COVID-19 Pandemic

Background & aim: SARS-CoV-2 infection is associated with increased cardiovascular (CV) morbidity and mortality, manifesting as increased adverse outcomes in the first 30 days, extending to 12 months. This study aimed to investigate trends in sudden unexpected deaths between 2018 and 2022, with a focus on CV deaths.

Method: A retrospective analysis was performed on autopsy reports (n=9,330) obtained from New South Wales Coroners Court, Australia, specifically targeting cases of unexplained deaths that occurred between 2018 and 2022. Statistical analysis was conducted using chi-square tests and a post hoc analysis with Bonferroni correction, as well as analysis of variance with multiple comparisons.

Results: There were 349 (18.3%) CV deaths in 2018, 346 (18.0%) in 2019, 338 (17.5%) in 2020, 395 (21.9%) in 2021, and (23.4%) 413 in 2022 (p=0.0002). Among CV deaths, the number of deaths from sudden arrhythmic death syndrome were 25 (7.2%) in 2018, 26 (7.5%) in 2019, 18 (5.3%) in 2020, 52 (13.2%) in 2021, and 80 (19.4%) in 2022 (p=0.0001). Atherosclerosis was the most common cause of death among all CV categories; there were 196 (56.2%) atherosclerosis deaths in 2018, 207 (59.8%) in 2019, 192 (56.8%) in 2020, 221 (56.0%) in 2021, and 197 (47.7%) in 2022 (p=0.43). The average age of death from sudden arrhythmic death syndrome (42.8±19.1 years) across 2018-2022 was younger than atherosclerosis (56.2±12.4 years) and total groups (53.1±15.1 years) (p<0.001). Males comprised 76% of all CV deaths from 2018 to 2022 (p<0.0001).

Conclusions: Compared with pre-pandemic data, a noteworthy increase in CV deaths was observed in occurrence with the escalation in COVID-19 cases in Australia. This may be attributed to direct or indirect factors, such as lifestyle modifications, disrupted access to routine cardiac care, or COVID-19 infection-triggered CV deaths.