Inclusion Criteria:  is 18 years or older at the index date. had ≥1 apixaban prescription during the study period from January 1st, 2015 to December 31, 2019. had ≥1 medical diagnosis for Atrial Fibrillation, AF (International Classification of Diseases, 10th Revision, Clinical Modification [ICD-10-CM]10 diagnosis codes I48.0, I48.1X, I48.11, I48.19, I48.2X, I48.20, I48.21, I48.9X, I48.91, I49.1) any time before or on index date had >1 encounter (visits, prescriptions, etc) within the EHRs.  Exclusion Criteria:  Medical EHRs indicating a diagnosis code indicative of rheumatic mitral valvular heart disease, mitral valve stenosis (ICD-10-CM diagnosis codes I05.x, I06.x, I07.x, I08.x, I34.x, I35.x, I36.x, I37.x, I38.x, I39.x, I37.x, Q23.x) during the 12-month baseline period, Medical EHRs indicating a diagnosis code of VTE (DVT: ICD-10-CM codes: I80.xx, I81.xx, I82.xx, I82.40x, I82.41x, I82.42x, I82.43x, I82.44x, I82.49x, I82.4Yx, I82.4Zx, I82.5xx, I82.51x, I82.52x, I82.53x, I82.54x, I82.55x, I82.56x, I82.59x, I82.5Yx, I82.5Zx, I82.62x, I82.72x, O22.0x, O22.2x, O22.3x; or PE: ICD-10-CM codes I26.01, I26.02, I26.09, I26.90, I26.92, I26.93, I26.94, I26.99) during the 12-month baseline period, Medical EHRs indicating a diagnosis (ICD-10-CM) or procedure code (International Classification of Diseases, 10th Revision, Procedure Coding System [ICD-10-PCS]10) of transient AF, or cardiac surgery: Heart valve replacement/transplant: 02YA0Zxx, 02RF0xx, 02RJ0xx, 02RG0xx, 02RH0xx, Z95.2, Z95.3, Z95.4; Pericarditis: I00, I01, I02, I24.1, I30.x, I31.x, I32*coding first the associated cause/etiology; Hyperthyroidism and Thyrotoxicity: E05.0, E05.1, E05.2, E05.3, E05.4, E05.8, E05.9) during the 12-month baseline period; Medical EHRs indicating pregnancy during the study period (ICD-10-CM diagnosis codes O00-O9A, Z31, Z32, Z33, Z34, Z36, Z37, Z38, O20-O29, ICD-10 CPS code 109xxx, 10Axxx, 10Dxxx, 10Exxx, 10Hxxx, 10Pxxx, 10Sxxx); Medical EHRs indicating diagnosis or procedure for hip/knee replacement surgery within 6 weeks prior to index date (0SR90xx, 0SRA0xx, 0SRB0xx, 0SRC0xx, 0SRD0xx, 0SRE0xx, 0SQ0xx, 0SQB0xx, 0SQB0xx, 0SQB0xx) Patients with a prescription for >1 anticoagulants at index date.