Non-valvular Atrial FibrillationNCT05438888

Safety and Effectiveness of Apixaban in Very Elderly Patients With Non-valvular Atrial Fibrillation (NVAF) Compared to Warfarin Using Administrative Claims Data

An observational study of Non-valvular Atrial Fibrillation, run by Pfizer at 1 site in Japan.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Trial summary

The objective of this study is to investigate safety and effectiveness of apixaban compared to warfarin in very elderly patients with Non-valvular atrial fibrillation (NVAF). In addition to the absolute age, effects on higher age-related risk factors on relative risk of apixaban to warfarin is also investigated… Read more about this study

Who is it for?: Ages 80 years and older
Conditions the study is for: Non-valvular Atrial Fibrillation
What is being tested?: Warfarin and Apixaban
How many people: 77,814 participants
Where: 1 siteJapan
Study dates: 1 Jul 2022to 19 Oct 2022
Phase: Observational
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 80 years and older
All sexes
No healthy volunteers
Older adult

Study population: Patients aged 80 years or older who are newly diagnosed with non-valvular atrial fibrillation (NVAF) and initiate anticoagulation therapy with warfarin or apixaban.

Who may be able to join

Patients must meet all the following inclusion criteria to be eligible for inclusion in the study.
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 (OAC)s during the baseline period (the 180 days before the index date)
Age of 18 years or older on the index date.
Index date is at age 80 or older

Who cannot join

Patients meeting any of the following criteria will not be included in the study:
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 cardiac surgery procedure record during the baseline period
Having a joint replacement procedure record during the baseline period
Having a procedure of prosthetic heart valve during the baseline period
Having a diagnosis of venous thromboembolism during the baseline period
Female patients with pregnancy during the follow-up period
Patients prescribed "off-label" doses of OACs (per Japanese package insert of each OAC) or patients treated with OAC but in "off-label" or "contraindicated" manners.

Trial locations and contacts

1 site in 1 country.

Japan1 site

Pfizer Site
Tokyo

Other trials in Japan

About this study

Official title: Safety and Effectiveness of Apixaban in Very Elderly Patients With NVAF Compared to Warfarin Using Administrative Claims Data

Read the detailed description

This is a retrospective non-intervention observational study to evaluate the difference in safety and effectiveness between apixaban and warfarin using a database provided by Medical Data Vision Co. Ltd. (MDV Co. Ltd.). Eligible patients will be extracted from the database and allocated to the pre-defined cohorts based on the actual age, age of NVAF diagnosis and types of anticoagulant therapy.

Patient characteristics will be balanced by an Inverse probability of treatment weighting (IPTW) method, and risk of stroke/SE (primary effectiveness endpoint) and major bleeding (primary safety endpoint) will be compared.

Conditions: Non-valvular Atrial Fibrillation
Being tested: Warfarin, Apixaban
Keywords: Stroke, Apixaban, Warfarin
Medical subject headings: Stroke

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

WarfarinDrug
This is observational study and the patients in the warfarin cohort include those who are exposed to warfarin in the real world settings.
ApixabanDrug
This is observational study and the patients in the apixaban cohort include those who are exposed to apixaban in the real world settings.

Study groups in NCT05438888
Study group	Role	What they receive
Warfarin cohort (Reference)		Patients with NVAF treated with warfarin Receives: Drug: Warfarin
Apixaban cohort		Patients with NVAF treated with apixaban Receives: Drug: Apixaban

What is being measured

The primary outcome is the main question the study is designed to answer.

Incidence Rate (Per 1,000 Participant-Year) of Composite of Stroke and Systemic Embolism (SE): Balanced Cohorts
Incidence rate per 1000 participant-years for the first occurrence of composite stroke and SE events after index date was reported. Stroke events included ischemic and hemorrhagic stroke. International Classification of Diseases 10th Revision (ICD-10) diagnosis code was used to label the events. Index date was defined as a date when participants initiated warfarin or apixaban. Follow-up period: the next day of the index date till occurrence of target outcome, discontinuation of the warfarin or apixaban, switching from the warfarin or apixaban, withdrawal from the database, whichever observed first.
Measured: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study
Incidence Rate (Per 1,000 Participant-Year) of Major Bleeding: Balanced Cohorts
Incidence rate per 1000 participant-years for the first occurrence of major bleeding event after index date was reported. Major bleeding was defined as any bleeding that required hospitalization for treatment. ICD-10 diagnosis code was used to label the events. Index date was defined as a date when participants initiated warfarin or apixaban. Follow-up period: the next day of the index date till occurrence of target outcome, discontinuation of the warfarin or apixaban, switching from the warfarin or apixaban, withdrawal from the database, whichever observed first.
Measured: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study

Secondary outcomes (5)

Incidence Rate (Per 1,000 Participant-Year) of Cardiogenic Cerebral Embolism: Balanced Cohorts
Incidence rate per 1000 participant-years for the first occurrence of cardiogenic cerebral embolism events after index date was reported. ICD-10 diagnosis code was used to label the events. Index date was defined as a date when participants initiated warfarin or apixaban. Follow-up period: the next day of the index date till occurrence of target outcome, discontinuation of the warfarin or apixaban, switching from warfarin or apixaban, withdrawal from the database, whichever observed first.
Measured: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study
Incidence Rate (Per 1,000 Participant-Year) of Ischemic Stroke (Cerebral Infarction): Balanced Cohorts
Incidence rate per 1000 participant-years for the first occurrence of ischemic stroke event after index date was reported. ICD-10 diagnosis code was used to label the events. Index date was defined as a date when participants initiated warfarin or apixaban. Follow-up period: the next day of the index date till occurrence of target outcome, discontinuation of the warfarin or apixaban, switching from warfarin or apixaban, withdrawal from the database, whichever observed first.
Measured: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study
Incidence Rate (Per 1,000 Participant-Year) of Intracranial Hemorrhage: Balanced Cohorts
Incidence rate per 1000 participant-years for the first occurrence of intracranial hemorrhage event after index date was reported. ICD-10 diagnosis code was used to label the events. Index date was defined as a date when participants initiated warfarin or apixaban. Follow-up period: the next day of the index date till occurrence of target outcome, discontinuation of the warfarin or apixaban, switching from warfarin or apixaban, withdrawal from the database, whichever observed first.
Measured: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study
Incidence Rate (Per 1,000 Participant-Year) of Gastrointestinal Bleeding: Balanced Cohorts
Incidence rate per 1000 participant-years for the first occurrence of major GI bleeding event after index date was reported. ICD-10 diagnosis code was used to label the events. Index date was defined as a date when participants initiated warfarin or apixaban. Follow-up period: the next day of the index date till occurrence of target outcome, discontinuation of the warfarin or apixaban, switching from warfarin or apixaban, withdrawal from the database, whichever observed first.
Measured: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study
Incidence Rate (Per 1,000 Participant-Year) of Intraocular Bleeding: Balanced Cohorts
Incidence rate per 1000 participant-years for the first occurrence of intraocular bleeding event after index date was reported. ICD-10 diagnosis code was used to label the events. Index date was defined as a date when participants initiated warfarin or apixaban. Follow-up period: the next day of the index date till occurrence of target outcome, discontinuation of the warfarin or apixaban, switching from warfarin or apixaban, withdrawal from the database, whichever observed first.
Measured: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

1 Jul 202219 Oct 2022

First posted30 Jun 2022
Study start1 Jul 2022
Primary completion19 Oct 2022
Study completion19 Oct 2022

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (1)Papers the sponsor has linked to this study.
Other trials for Non-valvular Atrial FibrillationStudies of the same condition, open and under way.
More trials run by PfizerThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Observational
Observational model: Cohort
Time perspective: Retrospective
Enrolment: 77,814 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05438888
Sponsor's protocol ID: B0661181
Status last verified: Oct 2023
First submitted: 25 Jun 2022
Last updated: 20 May 2024
Results posted: Yes, on ClinicalTrials.gov
Individual data sharing: No: 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.

Publications

Matsuo-Ohsawa A, Katada J, Kohsaka S. Safety and Effectiveness of Apixaban in Very Elderly Patients with Atrial Fibrillation: A Retrospective Analysis of Japanese Administrative Claims Data. Cardiol Ther. 2025 Dec;14(4):565-581. doi: 10.1007/s40119-025-00420-w. Epub 2025 Jul 8.
PubMed 40627071

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

Active, not recruiting
An Early Feasibility Study Evaluating the Safety and Efficacy of the Laminar Left Atrial Appendage Closure System in Subjects With Non-Valvular Atrial Fibrillation
Non-valvular Atrial Fibrillation
Active, not recruiting
CHAMPION-AF Clinical Trial
Atrial Fibrillation, Stroke
Not yet recruitingPhase 2
Vortosiran in Atrial Fibrillation
Non-valvular Atrial Fibrillation (AF)
Active, not recruitingObservational study
WATCHMAN FLX Pro European Registry
Non-valvular Atrial Fibrillation (AF), Left Atrial Appendage Closure
Active, not recruiting
LAmbre™ II Left Atrial Appendage Occluder and Occluder Delivery System for Patients With Non-Valvular Atrial Fibrillation
Non Valvular Atrial Fibrillation

All Non-valvular Atrial Fibrillation trials

Study at a glance

From the registry record, last updated by the sponsor on 20 May 2024. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Safety and Effectiveness of Apixaban in Very Elderly Patients With NVAF Compared to Warfarin Using Administrative Claims Data
ClinicalTrials.gov ID: NCT05438888
Acronym / sponsor ID: B0661181
Conditions: Non-valvular Atrial Fibrillation
Keywords: Stroke, Apixaban, Warfarin
Study type: Observational
Recruitment status: Completed
Enrolment: 77,814 participants (actual)
Lead sponsor: PfizerIndustry (pharma, biotech, devices)
Study start: 1 Jul 2022 (actual)
Primary completion: 19 Oct 2022 (actual)
Study completion: 19 Oct 2022 (actual)
First posted: 30 Jun 2022 (actual)
Results: Posted 20 May 2024

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Observational model: Cohort
Time perspective: Retrospective
Number of arms: 2

Arm	Type	Receives
Warfarin cohort (Reference)	–	Drug: WarfarinPatients with NVAF treated with warfarin
Apixaban cohort	–	Drug: ApixabanPatients with NVAF treated with apixaban

Who may qualify

Ages: 80 years and older
Sex: All
Healthy volunteers: Not accepted
Age groups: Older adult
Study population: Patients aged 80 years or older who are newly diagnosed with non-valvular atrial fibrillation (NVAF) and initiate anticoagulation therapy with warfarin or apixaban.

Key inclusion criteria (6 listed)

Patients must meet all the following inclusion criteria to be eligible for inclusion in the study.

Key exclusion criteria (8 listed)

Patients meeting any of the following criteria will not be included in the study:

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
WarfarinThis is observational study and the patients in the warfarin cohort include those who are exposed to warfarin in the real world settings.	Drug	Warfarin cohort (Reference)
ApixabanThis is observational study and the patients in the apixaban cohort include those who are exposed to apixaban in the real world settings.	Drug	Apixaban cohort

Primary outcome

Incidence Rate (Per 1,000 Participant-Year) of Composite of Stroke and Systemic Embolism (SE): Balanced Cohorts
Time frame: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study
Incidence rate per 1000 participant-years for the first occurrence of composite stroke and SE events after index date was reported. Stroke events included ischemic and hemorrhagic stroke. International Classification of Diseases 10th Revision (ICD-10) diagnosis code was used to label the events. Index date was defined as a date when participants initiated warfarin or apixaban. Follow-up period: the next day of the index date till occurrence of target outcome, discontinuation of the warfarin or apixaban, switching from the warfarin or apixaban, withdrawal from the database, whichever observed first.
Incidence Rate (Per 1,000 Participant-Year) of Major Bleeding: Balanced Cohorts
Time frame: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study
Incidence rate per 1000 participant-years for the first occurrence of major bleeding event after index date was reported. Major bleeding was defined as any bleeding that required hospitalization for treatment. ICD-10 diagnosis code was used to label the events. Index date was defined as a date when participants initiated warfarin or apixaban. Follow-up period: the next day of the index date till occurrence of target outcome, discontinuation of the warfarin or apixaban, switching from the warfarin or apixaban, withdrawal from the database, whichever observed first.

5 secondary outcomes

Incidence Rate (Per 1,000 Participant-Year) of Cardiogenic Cerebral Embolism: Balanced Cohorts
Time frame: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study
Incidence Rate (Per 1,000 Participant-Year) of Ischemic Stroke (Cerebral Infarction): Balanced Cohorts
Time frame: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study
Incidence Rate (Per 1,000 Participant-Year) of Intracranial Hemorrhage: Balanced Cohorts
Time frame: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study
Incidence Rate (Per 1,000 Participant-Year) of Gastrointestinal Bleeding: Balanced Cohorts
Time frame: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study
Incidence Rate (Per 1,000 Participant-Year) of Intraocular Bleeding: Balanced Cohorts
Time frame: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study

Results and safety

Results posted to the registry on 20 May 2024, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Warfarin Cohort	39,936	39,936
Apixaban Cohort	37,878	37,878

Primary outcome: Incidence Rate (Per 1,000 Participant-Year) of Composite of Stroke and Systemic Embolism (SE): Balanced Cohorts

Time frame: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study. Number (95% Confidence Interval). Unit: Events Per 1000 Participant-Years

Measure	Warfarin: Balanced Cohort n = 43671	Apixaban: Balanced Cohort n = 33834
Value	75.227 (72.579 to 77.972)	55.801 (53.328 to 58.388)

Warfarin: Balanced Cohort vs Apixaban: Balanced Cohort: Hazard Ratio (HR): 0.753 (95% CI 0.711 to 0.798), p <0.001, Log Rank

Population analysed: Eligible participants registered on MDV database, whose data was observed in the study. Analysis was performed using inverse probability treatment weighting with stabilized weights (s-IPTW) method to balance participant characteristics among reporting groups. Here, "Overall Number of Participants Analyzed" is the number of participants after application of s-IPTW method to raw numbers and is different from the actual participants included in the reporting arm.

Primary outcome: Incidence Rate (Per 1,000 Participant-Year) of Major Bleeding: Balanced Cohorts

Measure	Warfarin: Balanced Cohort n = 43671	Apixaban: Balanced Cohort n = 33834
Value	25.328 (23.836 to 26.914)	17.306 (15.973 to 18.751)

Warfarin: Balanced Cohort vs Apixaban: Balanced Cohort: Hazard Ratio (HR): 0.687 (95% CI 0.622 to 0.760), p <0.001, Log Rank

Population analysed: Eligible participants registered on MDV database, whose data was observed in the study. Analysis was performed using s-IPTW method to balance participant characteristics among reporting groups. Here, "Overall Number of Participants Analyzed" is the number of participants after application of s-IPTW method to raw numbers and is different from the actual participants included in the reporting arm.

5 secondary outcomes are reported in the full results.

Adverse events

Time frame: Not applicable as safety data was not planned to be collected during the study.. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Warfarin Cohort	0 of 0	0 of 0	0
Apixaban Cohort	0 of 0	0 of 0	0

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 20 May 2024.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Derived from this study: PubMed 40627071Matsuo-Ohsawa A, Katada J, Kohsaka S. Safety and Effectiveness of Apixaban in Very Elderly Patients with Atrial Fibrillation: A Retrospective Analysis of Japanese Administrative Claims Data. Cardiol Ther. 2025 Dec;14(4):565-581. doi: 10.1007/s40119-025-00420-w. Epub 2025 Jul 8.
To obtain contact information for a study center near you, click here.Link provided by the sponsor.
Individual participant dataSharing planned: No. 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.

Related trials for Non-valvular Atrial Fibrillation

Active, not recruiting
An Early Feasibility Study Evaluating the Safety and Efficacy of the Laminar Left Atrial Appendage Closure System in Subjects With Non-Valvular Atrial Fibrillation
Non-valvular Atrial Fibrillation
Active, not recruiting
CHAMPION-AF Clinical Trial
Atrial Fibrillation, Stroke
Not yet recruitingPhase 2
Vortosiran in Atrial Fibrillation
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Active, not recruitingObservational study
WATCHMAN FLX Pro European Registry
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Active, not recruiting
LAmbre™ II Left Atrial Appendage Occluder and Occluder Delivery System for Patients With Non-Valvular Atrial Fibrillation
Non Valvular Atrial Fibrillation

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Pfizer CT.gov Call Center study director

Pfizer

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

An observational study of Non-valvular Atrial Fibrillation, run by Pfizer at 1 site in Japan.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 6 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 20 May 2024. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Japan. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 20 May 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Incidence Rate (Per 1,000 Participant-Year) of Composite of Stroke and Systemic Embolism (SE): Balanced Cohorts (time frame: Follow-up period during data observation period from 26-Feb-2013 to 31-Dec-2021 (approximately 8 years 10 months); extracted data evaluated in approximately 3.5 months of this study). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05438888, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 May 2024.