NCT04650087.

Study name	COVID‐19 thrombosis prevention trials: post‐hospital thromboprophylaxis
Methods	Prospective, double‐blind RCT
Participants	Number of participants: 1223 Age: ≥ 18 years Gender: male or female Inclusion criteria PCR‐positive COVID‐19 infection Hospitalised for 2 or more days Exclusion criteria Pre‐existing indication for anticoagulation (e.g. PE or DVT; atrial fibrillation; mechanical cardiac valve) Contraindication to antithrombotic therapy (e.g. known bleeding within the last 30 days requiring emergency room presentation or hospitalisation; major surgery within 14 days; ischaemic stroke, intracranial bleed, or neurosurgery within 3 months) Platelet count < 50,000/µL Haemoglobin < 8 g/dL Renal insufficiency (GFR < 30 mL/min/1.73 m2) Pregnancy Prison inmate Life expectancy less than 90 days Unwilling or unable to provide informed consent/unwilling or unable to complete the study protocol Dual antiplatelet therapy that cannot be discontinued Concomitant need for strong inducers/inhibitors of P‐gp or CYP3A4
Interventions	Intervention: apixaban 2.5 mg twice a day, once in the morning and once in the evening for 30 days Control: placebo twice a day, once in the morning and once in the evening for 30 days
Outcomes	Primary outcomes Composite outcome of symptomatic DVT, PE, other VTE, ischaemic stroke, MI, other arterial thromboembolism, and all‐cause mortality as measured by hospital records (time frame: 30 days after hospital discharge) Secondary outcomes Composite outcome of all‐cause mortality and the EQ‐5D index score (time frame: 30 days after hospital discharge) Composite outcome of symptomatic DVT, PE, other VTE, ischaemic stroke, MI, other arterial thromboembolism, and all‐cause mortality as measured by hospital records (time frame: 45 days and 90 days after hospital discharge) New, symptomatic VTE for up to 30 days after randomisation as measured by hospital records (time frame: 30 days after randomisation) New, symptomatic arterial thromboembolism (inclusive of ischaemic stroke, MI, or peripheral arterial thromboembolism) for up to 30 days after randomisation as measured by hospital records (time frame: 30 days after randomisation) Other outcomes Incidence of all‐cause mortality (time frame: 30 days after hospital discharge) Incidence of all‐cause rehospitalisation for up to 90 days after randomisation (time frame: 30 days after hospital discharge) Individual domains of EQ‐5D and the EQ‐5D visual analogue scale for 30 and 90 days after randomisation (time frame: 30 and 90 days after hospital discharge)
Starting date	15 February 2021
Contact information	tracy.wang@duke.edu
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