On-admission versus in-hospital thromboembolism due to COVID-19 infection. What is the particular characteristic of those with early thrombotic events?

Introduction: Increasing evidence has declared a hypercoagulable state in the coronavirus 2019 infection (COVID-19), while the etiology has remained a question. For the first time, the current study has aimed to compare the contributors of thromboembolism among those whose primary manifestations of COVID-19 were thrombosis vs the patients with a thrombotic event during the period of hospitalization.Material and methods: This case-control study has been conducted on 267 COVID-19 patients, including 59, 48, and 160 ones with an on-admission, in-hospital, and without a thrombotic event, respectively. The events were defined as deep vein thrombosis (DVT), ischemic cerebrovascular accidents (CVA), pulmonary thromboembolism (PTE), or acute myocardial infarction (AMI). The demographic, physical examination, clinical and laboratory assessments of the groups were compared.Results: The DVT (OR: 5.18; 95% CI: 1.01–26.7), AMI (OR: 11.1; 95% CI: 2.36–52.3), and arterial thrombosis (OR: 5.93; 95% CI: 0.63–55.8) were significantly associated with an on-admission thrombosis compared to those who presented in-hospital events. Lower levels of oxygen saturation were the only significant predictor index inversely associated with on-admission thrombosis compared to those with an event during the hospital admission period.Conclusion: PTE development was the most common in-hospital thrombotic event, whereas other thromboembolism types were remarkably more often among cases with on-admission events. Oxygen saturation was the only predictor of premature thrombosis that was inversely associated with outpatient events