Real-world Comparative Effectiveness of Dabigatran Versus Vitamin K Antagonist

Inclusion Criteria: * Non-valvular atrial fibrillation will be defined as the occurrence of 2 or more inpatient or outpatient claims with ICD-9 427.31 (International Classification of Disease, Ninth Revision, Clinical Modification) as the diagnosis code at any time in the patient's data history prior to inclusion * Patients will be required to have 180 days of enrollment for the assessment of baseline characteristics * CHA2DS2-Vasc (Diabetes mellitus; S2: prior Stroke or TIA or Thromboembolism; V: Vascular disease; A: Age 65-74 years; Sc: Sex category ) score ≥2 during the 180 days prior to index dabigatran use baseline period Exclusion Criteria: * Patients \<18 years of age * Patients with valvular Atrial fibrillation * Pregnancy * Malignant cancers * Transient cause of Atrial fibrillation * Patients with Venous thromboembolism (pulmonary embolism or Deep Vein Thrombosis) * Patients with major surgery defined as hip or knee replacement * Prescriptions of Oral anticoagulants (OACs) {apixaban, warfarin, dabigatran, rivaroxaban} before index date * Prescription of more than one OAC on the index date * Patient with any of the events defined in the composite endpoint