Inclusion Criteria:  Be ≥20 years of age (legal age in Korea) at the time of anticoagulation initiation Have a diagnosis of NVAF (in the 24-months prior to index date) Have no record of OAC use (in the 24-months prior to index date) Newly initiated on rivaroxaban or warfarin (index date)  Exclusion Criteria:  Who have end-stage renal disease or are on dialysis (in the 12-months prior to index date) With evidence of valvular heart disease (in the 12-months prior to index date) With pulmonary embolism or deep vein thrombosis (within 6 months before index date) Who received joint replacement (within 6 months before diagnosis) Patients who had previous OAC prescription between 2013 and 2014 With rivaroxaban doses other than 15 or 20 mg once daily