The overall objective of this proposal is to execute a real-world database analysis to evaluate hospital readmissions among hospitalized nonvalvular atrial fibrillation (NVAF) patients in the U.S.

Inclusion Criteria:

• Have a primary or secondary diagnosis of AF identified by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes from the Cerner Health Facts hospital database between January 1, 2012 and August 31, 2014
• Age 18 years or older as of initial hospitalization with AF diagnosis

Exclusion Criteria:

• Have any primary or secondary diagnosis code or procedure code for valvular disease during the study period. This exclusion criterion is consistent with that used in other previous BMS Health Economics and Outcomes Research (HEOR) studies and is used to ensure that the study populations are NVAF patients
• Received multiple types of NOACs during the index hospitalization. Preliminary analysis showed that very few patients receive multiple types of NOACs during the same hospitalization. This exclusion criterion will allow to cleanly group patients into the different New oral anticoagulant (NOAC) usage groups

Patients who received any of the NOACs, dabigatran, rivaroxaban, apixaban, or warfarin during any time of the hospitalization (from admission to discharge)