Apixaban Safety and Therapy Adherence in Patients With Atrial Fibrillation

Monitoring Safety and Therapeutic Adherence During Anticoagulant Prophylaxis With Apixa® in Patients With Nonvalvular Atrial Fibrillation (Praćenje Sigurnosti i Terapijske Adherence u Toku Antikoagulantne Profilakse Lijekom Apixa® Kod Pacijenata sa Nevalvularnom Atrijalnom Fibrilacijom)

The aim of this observational study is to evaluate safety and therapeutic adherence during anticoagulant prophylaxis with apixaban in patients with nonvalvular atrial fibrillation. The main questions it aims to answer are:

• What is the incidence of major bleeding and clinically relevant non-major bleeding during anticoagulant prophylaxis with apixaban in patients with nonvalvular atrial fibrillation?
• What is therapy adherence during anticoagulant prophylaxis with apixaban in patients with nonvalvular atrial fibrillation?
• What is frequency and types of other adverse reactions, excluding bleeding, during anticoagulant prophylaxis with apixaban in patients with nonvalvular atrial fibrillation? Participants will be followed for six months through four measurements. The first and fourth measurements will be performed in person, while the remaining measurements can also be recorded by telephone, if the patient's condition allows. Any bleeding or serious adverse reactions to the medication being administered will be recorded immediately, through unscheduled measurements. Adverse reactions will be recorded at each measurement. Adherence to the medication being administered will be evaluated using the BARS scale.

Study Overview

• Status: Recruiting
• Conditions: Nonvalvular Atrial Fibrillation
• Intervention / Treatment: Drug: Apixaban

• Study Type: Observational
• Enrollment (Estimated): 800

Contacts and Locations

• Study Contact: Name: Halima Karakaš; Phone Number: +387 62 478 535; Email: HalimaK@Bosnalijek.ba
• Study Contact Backup: Name: Una Glamoclija, PhD; Phone Number: +387 61 147 401; Email: UnaG@Bosnalijek.ba

Study Locations

• Bosnia and Herzegovina
  • Sarajevo, Bosnia and Herzegovina, 71000
    • Recruiting
    • Clinic for diseases of the heart, blood vessels and rheumatism
    • Contact: Alden Begić, PhD; Phone Number: +387 33 297 500; Email: alden.begic@kcus.ba
    • Principal Investigator: Alden Begić, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Eligible patients from participating centers from Bosnia and Herzegovina who are treated on an outpatient basis or in a hospital setting.

Description

Inclusion Criteria:

• Patients over 18 years of age.
• Hemodynamically stable patients.
• Patients with non-valvular atrial fibrillation.
• Patients in whom the investigator, based on clinical assessment makes a decision to introduce apixaban therapy.
• Patients who are on apixaban therapy for the first time

Exclusion Criteria:

• Positive history of angioneurotic edema.
• Active, clinically significant bleeding.
• Congenital or acquired bleeding disorder.
• The presence of a malignant tumor.
• Current or recent presence of gastrointestinal ulcer.
• The presence of established or suspected esophageal varices.
• Positive history of arteriovenous malformations, vascular aneurysms or intraspinal and intracerebral vascular anomalies.
• Patients with artificial heart valves.
• Liver cirrhosis and active liver disease associated with coagulopathy and clinically significant risk of bleeding.
• Dialysis patients (GFR <15 ml/min).
• Simultaneous use of other anticoagulants.
• Pregnancy and breastfeeding.
• Patients who previously used apixaban in therapy.

Withdrawal Criteria:

• Deterioration of the clinical picture of the underlying disease that requires discontinuation of investigational therapy.
• Development of serious adverse events that require discontinuation of therapy.
• Occurrence of pregnancy.
• Development of another disease that affects the course of research.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Apixaban; Patients with nonvalvular atrial fibrillation receiving apixaban therapy	Drug: Apixaban; Patients will receive orally 5 mg of apixaban twice daily or reduced dose 2.5 mg, twice a day orally, in patients with at least two of the following characteristics: age ≥ 80 years, body weight ≤ 60 kg or serum creatinine ≥ 1.5 mg/dl (133 μmol/l).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Composite primary outcome including incidence of major bleeding and clinically relevant non-major bleeding	The primary outcome will be bleeding, composed of major bleeding reported according to the International Society on Thrombosis and Haemostasis (ISTH) criteria and non-major bleeding including prolonged bleeding from cuts on the skin, bleeding from gums or nose, blood in the stool and/or urine, vomiting and/or coughing up blood, and prolonged or heavier menstruation.	From enrollment to the end of study after six months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Monitoring the composite outcome of major, clinically relevant non-major and minor bleeding	This aim will include any form of bleeding recorded during the study	From enrollment to the end of study after six months
Monitoring the frequency and type of other adverse reactions, excluding bleeding		From enrollment to the end of study after six months
Monitoring of adherence to anticoagulant prophylaxis	Adherence to the administered medication will be evaluated using the Brief Adherence Rating Scale (BARS). The final scale has range from 0 to 100, higher values meaning better adherence.	From enrollment to the end of study after six months

Collaborators and Investigators

• Sponsor: Bosnalijek D.D

Study record dates

Study Major Dates

• Study Start (Actual): October 9, 2025
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): April 1, 2027

Study Registration Dates

• First Submitted: March 4, 2026
• First Submitted That Met QC Criteria: March 4, 2026
• First Posted (Actual): March 9, 2026

Study Record Updates

• Last Update Posted (Actual): March 11, 2026
• Last Update Submitted That Met QC Criteria: March 9, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: apixaban
• Other Study ID Numbers: APX-01-2025

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No