To obtain a better understanding on the comparative effectiveness of dabigatran versus Vitamin K antagonist (VKA) for stroke prevention in patients with Non-valvular atrial fibrillation (NVAF) in a real-life setting.

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

Patients with non-valvular atrial fibrillation (NVAF).