Cardiovascular outcomes for people hospitalised with COVID-19 in Australia, and the effect of vaccination: an observational cohort study.

Objectives: To assess the frequency of clinical cardiovascular outcomes for people hospitalised with coronavirus disease 2019 (COVID-19), and the impact of vaccination.

Study Design: Observational cohort study.

Setting, Participants: All index admissions of adults with laboratory-confirmed COVID-19 to 21 hospitals participating in the Australian Cardiovascular COVID-19 Registry (AUS-COVID), 4 September 2020 - 11 July 2022.

Main Outcome Measures: Frequency of elevated troponin levels, new arrhythmia, new or deteriorating heart failure or cardiomyopathy, new pericarditis or myocarditis, new permanent pacemaker or implantable cardioverter-defibrillator, and pulmonary embolism.

Secondary Outcomes: impact of COVID-19 vaccination on likelihood of in-hospital death, intubation, troponin elevation, and clinical cardiovascular events.

Results: The mean age of the 1714 people admitted to hospital with COVID-19 was 60.1 years (standard deviation, 20.6 years); 926 were men (54.0%), 181 patients died during their index admissions (10.6%), 299 required intensive care (17.4%). Thirty-eight patients (2.6%) developed new atrial fibrillation or flutter, 27 (2.6%) had pulmonary embolisms, new heart failure or cardiomyopathy was identified in 13 (0.9%), and pre-existing cardiomyopathy or heart failure was exacerbated in 21 of 110 patients (19%). Troponin was elevated in 369 of the 986 patients for whom it was assessed (37.4%); in-hospital mortality was higher for people with elevated troponin levels (86, 23% v 23, 3.7%; P < 0.001). The COVID-19 vaccination status of 580 patients was known (no doses, 232; at least one dose, 348). The likelihood of in-hospital death (adjusted odds ratio [aOR], 0.38; 95% confidence interval [CI], 0.18-0.79) and intubation (aOR, 0.30; 95% CI, 0.15-0.61) were lower for people who had received at least one vaccine dose, but not the likelihood of troponin elevation (aOR, 1.44; 95% CI, 0.80-2.58) or clinical cardiovascular events (aOR, 1.56; 95% CI, 0.59-4.16).

Conclusions: Although troponin levels were elevated in a considerable proportion of people hospitalised with COVID-19, clinical cardiovascular events were infrequent, and their likelihood was not influenced by vaccination. COVID-19 vaccination, however, was associated with reduced likelihood of in-hospital death and intubation.

Trial Registration: Australian and New Zealand Clinical Trials Registry, ACTRN12620000486921 (prospective).