Background and Objective:
Several studies have shown an increased frequency of cardiovascular and respiratory events, a part of the long COVID presentation. We aimed to describe the incidence of pre-specified cardiovascular and respiratory events after a COVID-19 hospitalisation.

Methods:
We retrospectively collected data from individuals hospitalised due to COVID-19 between March 2020 and March 2021 in six Portuguese hospitals. The cardiovascular events considered were: heart failure, myocarditis, arrhythmia, acute myocardial infarction, deep vein thrombosis, ischemic stroke, and hemorrhagic heart attack; and the respiratory events considered were: pulmonary thromboembolism, pulmonary fibrosis, chronic or prolonged respiratory failure, obstructive/restrictive lung disease, and organising pneumonia. We estimated incidence and 95% confidence intervals.

Results:
Data collection is still ongoing. For this preliminary analysis, 1438 individuals were included. The median age was 70, 53% were male, and 12% died after hospital discharge. Individuals were in the study for a median of 17 months. Most individuals (66%) had moderate COVID-19, corresponding to supplementary oxygen use during hospitalisation, and 14% had severe COVID-19, needing ventilation or admission to ICU. During the study period, 98 cardiovascular and 85 respiratory events were registered, corresponding to an incidence of 3.5 (95% CI: 2.8; 4.3) and 3.9 (95% CI: 3.1; 4.9) cases per 1000 person-years, respectively. Overall, 172 events were registered, corresponding to an incidence of 107.9 (95% CI: 92.4; 125.3) cases per person-years. The incidence of cardiovascular and/or respiratory events increased according to the severity of the COVID-19 episode (mild – 75.7 (95% CI: 48.5; 112.6), moderate – 109.3 (95% CI: 90.1; 131.4) and severe – 143.9 (95% CI: 100.2; 200.1) cases per person-years, respectively).

Conclusion:
Comparisons with the expected incidence rates in the absence of COVID-19 are required; nevertheless, our preliminary results indicate that the frequency of events increases with increasing COVID-19 severity.