Why is this study important?

Outpatients with Covid-19 infection during the pandemic were suspected to be at increased risk for venous and arterial thrombotic events. In fact, histopathological evidence suggests that part of the worsening of lung function in these patients leading to their hospitalization is due to microvascular and macrovascular vascular thrombosis. Thus, there has been a suggestion that the prophylactic use of anticoagulants in such patients can be beneficial. 

What question was this study supposed to answer?

Does the early initiation of thromboprophylaxis with rivaroxaban in higher risk symptomatic outpatients with Covid-19 lower their risk of having venous and arterial thrombotic events, reduce the in situ pulmonary thrombosis and worsening of pulmonary function leading to hospitalization and reduce all-cause mortality? 

What did the study show?

This was a relatively large randomized, double-blind, placebo controlled, event-driven study performed on 1,284 patients ≥ 18 years over a period of 49 (± 7) days. 

The study showed that rivaroxaban when prescribed for 35 (± 6) days in non-hospitalized patients with symptomatic Covid-19 who were at high risk for thrombosis did not reduce the composite endpoint of venous and arterial thrombotic events, hospitalization, and death (3.4% vs. 3.0%, p=0.626). However, a post hoc analysis showed a significant reduction in venous and arterial thrombotic events (p=0.025). There was also an overall low incidence of bleeding events in the study.

Key Takeaways

• The study is underpowered to provide a definitive conclusion. 
• However, it appears that the findings presented do not support the routine use of antithrombotic prophylaxis in non-hospitalized patients with symptomatic Covid-19.