Interaction term analysis result was not significant and thus comparative effectiveness for primary and secondary outcomes could not be considered per protocol.

Old age, less body weight and deteriorated renal function are significant clinical factors for the outcomes of atrial fibrillation- so called 'fragile'- and these are common risk factors in osteoporosis and fracture. Therefore, in real world, these risk factors and co-morbidities are commonly considered when it comes to prescribe anticoagulant in atrial fibrillation patients. Recent study even reported that comorbid atrial fibrillation in patients with osteoporosis might be associated with an increased risk of bone fracture and death after fracture. Because there have been very few data about the effectiveness/safety of anticoagulant among non-valvular atrial fibrillation with prior osteoporosis/fracture, this study is planned to provide real-world evidences for this specific type of non-valvular atrial fibrillation patients.

Inclusion Criteria:

• Patients aged 18 years or older on the index date
• Patients had ≥1 medical claim for atrial fibrillation with at least one hospitalization or at least two outpatient visits during the reference period

Exclusion Criteria:

• Patients with valvular atrial fibrillation or transient atrial fibrillation
• Having ≥ 2 types of oral anticoagulant on the index date
• who have contraindications to oral anticoagulant
• confounder factors related to the outcome (osteoporotic fractures)

Non-valvular atrial fibrillation patients with warfarin or apixaban user

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.