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).