Adverse Drug Events in Patients on Oral Anticoagulation in the Emergency Department

Rationale: According to the latest National Survey on Care-Related Adverse Events, anticoagulants, including vitamin K antagonists (VKAs), rank first among medications responsible for serious iatrogenic accidents (37% in 2004, 31% in 2009). The EMIR study (2007) showed that VKAs were the leading cause of hospitalization for adverse effects (12.3%), with approximately 5,000 fatal hemorrhage-related accidents annually. Treatment and prevention of thromboembolic events represent a major public health challenge due to increased mortality, severity of functional sequelae, growing number of patients requiring treatment, and medical, social, and economic consequences. In 2013, an estimated 3.12 million patients received anticoagulation (4-5% of the French population). Several types of adverse events under oral anticoagulation appear to have high incidence in emergency settings: traumatic hemorrhage, spontaneous hemorrhage, asymptomatic overdose, and thrombosis. Different variables are associated with these events in patients admitted to emergency departments under oral anticoagulant treatment, but few studies have been conducted in real-world settings with large patient samples. Hypothesis: Iatrogenic events have a high incidence in patients admitted to emergency departments under oral anticoagulants and are a factor in early and late morbidity and mortality. Primary 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