Study to Gain Information on the Drug Xarelto for the Prevention of Brain Attack and Blockage of an Artery in the Non-central Nervous System Due to Irregular Heartbeat in Taiwanese Patients Suffering From Decreased Renal Function

Inclusion Criteria: * Female and male patients ≥ 20 years of age * Diagnosis of non-valvular atrial fibrillation (NVAF) * Patients for whom the decision to initiate treatment with rivaroxaban is made as per physician's routine treatment practice * Previously documented CrCl of 15-50 mL/min within 6 months before enrollment (last available value) Exclusion Criteria: * Contraindications for rivaroxaban according to the local market authorization/ Summary of Product Characteristics * Patients participating in an investigational program with interventions outside of routine clinical practice. * Planned treatment with other anticoagulants * Expected renal-replacement therapy within the next 3 months