Objective: To describe the characteristics of patients admitted to the emergency department on oral anticoagulant therapy, with a particular focus on characterizing those presenting with Adverse Drug Events (ADEOA). Study

Design: * Type: Observational, descriptive study * Duration: 36 months total (24 months for data collection, 12 months for analysis) * Sample Size: Estimated 2,080 patients (approximately 20 patients/week over 2 years) Inclusion Criteria: * Age ≥18 years * Admission to adult emergency department * Study period: January 1, 2018 to December 31, 2019 * Current oral anticoagulation therapy with: * Acenocoumarol (Sintrom®/Minisintrom®) * Apixaban (Eliquis®) * Dabigatran (Pradaxa®) * Fluindione (Previscan®) * Rivaroxaban (Xarelto®) * Warfarin (Coumadine®) Exclusion Criterion: \- Discontinuation of anticoagulant therapy for more than 24 hours Primary Outcome Measures: 1. Description of oral anticoagulant groups based on medication type 2. Characterization of Adverse Drug Events in Patients on Oral Anticoagulation in the Emergency Department (ADEOA): 1. Presence of ADEOA: * Traumatic hemorrhage: acute bleeding following recent trauma * Spontaneous hemorrhage: acute bleeding unrelated to recent trauma * Asymptomatic overdose: INR \>3 for vitamin K antagonist patients * Thrombosis: new arterial or venous thrombosis despite ongoing anticoagulation 2. Absence of ADEOA Secondary Outcome Measures: 1. Assessment of adherence to oral anticoagulant prescribing guidelines 2. Identification of etiological factors for anticoagulation-related adverse events 3. Identification of early morbidity and mortality risk factors 4. Evaluation of medical-economic impact of adverse events and cost-effectiveness analysis of adverse events 5. Quality of life assessment