Safety and Effectiveness of Apixaban Compared to Warfarin in Patients With Non-valvular Atrial Fibrillation (a Type of Irregular Heart Rhythm) at Higher Chance of Bleeding

Study Overview
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Brief Summary
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The purpose of this study is to compare effectiveness and safety of warfarin and apixaban among non-valvular atrial fibrillation (NVAF) patients at higher chance of bleeding using a Japanese nation-wide administrative claims database. Atrial fibrillation (AF) is characterized by a fast, irregular heartbeat which can cause blood to pool in the atria and increase the chance of the formation of blood clots. An anticoagulation therapy is a critical treatment to prevent thromboembolism in NVAF patients. Apixaban was demonstrated superiority compared to warfarin in preventing stroke or systemic embolism, caused less bleeding, and resulted in lower mortality in patients with AF in Phase 3 clinical trial. Previously we have shown that bleeding risks as well as stroke/SE risks are less in real world clinical practice in Japan compared to warfarin. However there are limited apixaban data for Japanese NVAF patients with high bleeding risk(s). This study will evaluate the risk of stroke/systemic embolism as well as the risk of bleeding in the real world settings in Japanese patients with NVAF who has higher chance of bleeding

Official Title
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Safety and Effectiveness of Apixaban Compared to Warfarin in NVAF Patients at Higher Risk of Bleeding.

Conditions
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Non-valvular Atrial Fibrillation

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosed with atrial fibrillation (AF) anytime in the baseline period or on the index date, also have definitive diagnosis of AF anytime in the baseline period, on the index date, or post-index period. Prescribed apixaban or warfarin on or after the day of AF diagnosis. The first observed prescription will be used to identify the patient's index date and treatment cohort No use of the any oral anticoagulants (OACs) during the baseline period (the 180 days before the index date) Age of 18 years or older on the index date Exclusion Criteria: Having a diagnosis of valvular atrial fibrillation, post-operative atrial fibrillation, rheumatic atrial fibrillation or mechanical-valvular atrial fibrillation during the baseline and post-index period Having a procedure of prosthetic heart valve during the baseline period Having a cardiac surgery procedure record during the baseline period Having a diagnosis of venous thromboembolism during the baseline period Having a hemodialysis during the baseline period Female patients with pregnancy during the baseline and follow-up period Patients prescribed apixaban other than approved daily dose (<5 mg or >10 mg) Patients prescribed OACs during baseline period

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to incidence of a composite stroke and systemic embolism |  | Maximum of 14 years (from 2008 to 2021) | 
| Time to incidence of Major bleeding events | Major bleeding is defined as any bleeding requiring hospitalization | Maximum of 14 years (from 2008 to 2021) |