Table 1.

Domains to be addressed with their respective PICO questions.

Domain	PICO Question
Domain 1: thromboprophylaxis in COVID-19 patients not requiring hospital admission.	PICO 1: Which patients with COVID-19 not requiring hospital admission should receive standard-doses of pharmacological thromboprophylaxis? P: COVID-19 patient without hospital admission criteria I: standard-doses of pharmacological thromboprophylaxis C: recommend mobilization (avoid sedentarism) but without pharmacological thromboprophylaxis O: symptomatic VTE
Domain 2: thromboprophylaxis in hospitalized COVID-19 patients.	PICO 2: In hospitalized patients for COVID-19 who were receiving anticoagulation with oral anticoagulants prior to admission, should we substitute them with LMWH? P: COVID-19 patients admitted in a conventional ward who received previous oral anticoagulant treatment I: LMWH at anticoagulant dose C: the same oral anticoagulant treatment prior to admission O: the same goal of oral anticoagulation (prevent arterial or venous thrombosis)
	PICO 3: What is the optimal dose of LMWH for most COVID-19 patients admitted to a conventional hospital ward? P: COVID-19 patients admitted to a conventional hospital ward I: intermediate or therapeutic doses of LMWH C: standard doses of pharmacological thromboprophylaxis O: symptomatic VTE/need for NIMV-IOT-ECMO/mortality/major bleeding
	PICO 4: What is the optimal dose of LMWH for most COVID-19 patients admitted to an Intensive Care Unit (ICU)? P: COVID-19 patients admitted to an ICU I: intermediate or therapeutic doses of LMWH C: standard-doses of pharmacological thromboprophylaxis O: symptomatic VTE/need for NIMV-IOT-ECMO/mortality/major bleeding
Domain 3: diagnosis and treatment guide of vte in COVID-19 hospitalized patients.	PICO 5: Which is the significance of high D-dimer levels in hospitalized patients for COVID-19? P: patients admitted for COVID-19 I: does the D-dimer have other utilities (diagnostic or therapeutic) in this context? C: continue using D-dimer in the context of low clinical suspicion due to its high negative predictive value O: symptomatic VTE/COVID-19 severity/mortality
Domain 4: follow-up after discharge of patients admitted for COVID-19 with and without a vte event.	PICO 6. Which patients without COVID-19-associated VTE should receive extended standard-doses thromboprophylaxis after hospital discharge? P: patients without VTE during hospitalization for COVID-19 at hospital discharge I: extended thromboprophylaxis after discharge C: thromboprophylaxis during hospitalization O: symptomatic VTE/major bleeding/mortality
	PICO 7. Which is the optimal duration of anticoagulant treatment for patients with COVID-19 associated VTE? P: patient suffering VTE (proximal DVT and/or PE) associated with COVID-19 I: extended anticoagulant treatment (beyond the first 3 months) C: anticoagulant treatment for 3 months O: symptomatic recurrent VTE/major bleeding/clinically relevant non-major bleeding/mortality

Abbreviations. COVID-19: coronavirus disease 2019; PICO: Patient, Intervention, Comparison, Outcomes; VTE: venous thromboembolic disease; LMWH: low molecular weight heparins; NIMV-IOT-ECMO: non-invasive mechanical ventilation-orotracheal intubation-extracorporeal membrane oxygenation; ICU: Intensive Care Units.