Rivaroxaban in Outpatients with Mild or Moderate COVID-19: Rationale and Design of the Study CARE (CARE - Coalition COVID-19 Brazil VIII).

Background: Previous studies have demonstrated a high risk of arterial and venous thromboembolic events as a consequence of direct viral damage to endothelial cells by SARS-CoV-2 and a procoagulant milieu due to increased biomarkers, such as D-dimer, fibrinogen, and factor VIII. Although randomized controlled trials of antithrombotic therapies have been conducted in hospitalized patients, few have evaluated the role of thromboprophylaxis in an outpatient setting.

Objective: To assess whether antithrombotic prophylaxis with rivaroxaban reduces the risk of venous or arterial thrombotic events, invasive ventilatory support, and death in COVID-19 outpatients.

Methods: The COVID Antithrombotic Rivaroxaban Evaluation (CARE) study, a multicenter, randomized, open-label, controlled trial of rivaroxaban 10 mg once daily for 14 days or local standard treatment alone to prevent adverse outcomes, is registered in clinicaltrials.gov (NCT04757857). The inclusion criteria are adults with confirmed or suspected SARS-CoV-2 infection and mild or moderate symptoms without indication for hospitalization, within 7 days of symptom onset, and 1 risk factor for COVID-19 complication (> 65 years, hypertension, diabetes mellitus, asthma, chronic obstructive pulmonary disease or other chronic lung diseases, smoking, immunosuppression, or obesity). The primary composite endpoint, which includes venous thromboembolism, invasive mechanical ventilation, major acute cardiovascular events, and mortality within 30 days of randomization, will be assessed according to the intention-to-treat principle. All patients will provide informed consent. A significance level of 5% will be used for all statistical tests.

Results: Major thrombotic and bleeding outcomes, hospitalizations, and deaths will be centrally adjudicated by an independent clinical events committee blinded to the assigned treatment groups.

Conclusion: The CARE study will provide relevant and contemporary information about the potential role of thromboprophylaxis in outpatients with COVID-19.