BRAVO - Betrixaban Registry Using Real Time Observations in Acute Medical Illness to Assess Venous Thrombosis and Bleeding Outcomes

Inclusion Criteria: -Part 1 - 1. Hospitalized acutely ill medical patient 2. Patient prescribed betrixaban 3. Signed informed consent Part 2 - 1. Hospitalized acutely ill medical patient 2. Patient prescribed betrixaban OR must satisfy criteria a and b: 1. Moderately or severely restricted immobility: patient restricted to bed for at least 24 hours (severe) or restricted to bed for at least 12 hours (moderate) during their hospitalization 2. At least One additional risk factor: Age \> 70 years D-dimer \> 2x institutional Upper Limit of Normal (ULN) Obesity: Body mass index (BMI) \> 30 kg/m2) History of pulmonary embolism (PE) or deep venous thrombosis (DVT) Active cancer (diagnosed, treated, or progressing in the past 6 months) History of thrombophilia Recent trauma or surgery (within 30 days prior to admission) Ongoing hormonal treatment ICU stay 3. Signed informed consent Exclusion Criteria: * Part 1 - 1. High bleeding risk - any of the following: 1. Patient on dialysis 2. Low platelet count (\<50 per 109/L) 3. Known bleeding disorder (congenital or acquired) 4. Liver disease prohibitive to anticoagulation 5. Bleeding within last 30 days 6. Use of Dual Anti-Platelet Therapy (DAPT) Part 2 1. Patients who are on another oral anticoagulant (OAC) for any reason at the time of hospitalization and will remain on it 2. Condition requiring use of OAC at admission, other than VTE prophylaxis (eg, acute VTE at admission) 3. High bleeding risk any of the following: 1. Patient on dialysis 2. Low platelet count (\<50 per 109/L) 3. Known bleeding disorder (congenital or acquired) 4. Liver disease prohibitive to anticoagulation 5. Bleeding within last 30 days 6. Use of Dual Anti-Platelet Therapy (DAPT)