Thromboembolic events in COVID-19 ambulatory patients: An observational study about incidence, and thromboprophylaxis outcomes

PLoS One. 2022 Aug 4;17(8):e0270195. doi: 10.1371/journal.pone.0270195. eCollection 2022.


Introduction: There are no clear data about the incidence and the prophylactic strategies of arterial and venous thromboembolic events (TE) in COVID-19 ambulatory patients. Thus, we conducted this study to analyze thromboembolic complications in this setting and to assess thromboprophylaxis management and outcomes in the real life.

Patients and methods: This is an observational study including Covid-19 ambulatory patients. We assessed incidence of venous and arterial TE events as well as thromboprophylaxis outcomes and hemorrhagic complications. We defined high risk thrombo-embolic factor according to the Belgian guidelines which are the only guidelines that described thromboprophylaxis in COVID-19 ambulatory patients.

Results: We included 2089 patients with a mean age of 43±16 years. The incidence of 30 days venous and arterial TE complications in our cohort was 1%. Venous thromboembolic complications occurred in 0.8% and arterial thromboembolic complications occurred in 0.3%.We noted at least one high-risk TE factor in 18.5% of patients but thromboprophylaxis was prescribed in 22.5% of the cases, LMWH in 18.1%, and Rivaroxaban in 3.7%. Hemorrhagic events occurred in eight patients (0.3%): five patients showed minor hemorrhagic events and three patients showed major ones (0.14%).

Conclusions: Our study showed that the incidence of thromboembolic complications is very low in COVID-19 ambulatory patients. Paradoxically, there is an over prescription of thrombo-prophylaxis in this population.

Publication types

  • Observational Study

MeSH terms

  • Adult
  • Anticoagulants / therapeutic use
  • COVID-19* / complications
  • COVID-19* / epidemiology
  • Hemorrhage / chemically induced
  • Hemorrhage / complications
  • Hemorrhage / epidemiology
  • Heparin, Low-Molecular-Weight / therapeutic use
  • Humans
  • Incidence
  • Middle Aged
  • Venous Thromboembolism* / epidemiology
  • Venous Thromboembolism* / etiology
  • Venous Thromboembolism* / prevention & control


  • Anticoagulants
  • Heparin, Low-Molecular-Weight

Grant support

The author(s) received no specific funding for this work.