Subtherapeutic INR Levels in Patients With AVK: Incidence, Associated Factors, Prognosis and Control Strategies

A Prospective Observational Study Assessing the Management of Anticoagulation With Vitamin K Antagonists in Patients With Nonvalvular Atrial Fibrillation Treated in Cardiology Practices

This prospective observational study is to assess the predictive factors of poor control of international normalized ratio (INR) to determine the treatment strategies received by patients with a poor control of INR in real-life clinical practice and to explore the effectiveness and safety of these strategies in patients with non-valvular atrial fibrillation who start vitamin K antagonist (VKA) treatment

Inclusion Criteria:

• Patients aged ≥ 18 years.
• Patients with a diagnosis of nonvalvular atrial fibrillation according to the criteria of the Spanish Agency of Medicines and Medical Devices (AEMPS) (2013) who are treated in cardiology practices.
• Patients about to start treatment with a vitamin K antagonist or who are in the first two months of treatment.
• Patients for whom access to at least 80% of INR tests performed during treatment with vitamin K antagonists is expected to be available.
• Patients with the mental and physical capacity to complete the study questionnaires and give their informed consent to participate in the study.

Exclusion Criteria:

• Patients with mitral stenosis or another significant valve disease for which specific treatment is scheduled or has already been performed (prosthesis or valvuloplasty).
• Patients hospitalised at the time of inclusion in the study.
• Patients with a life expectancy of less than 13 months.
• Patients who are participating in a clinical trial.
• Patients receiving double antiplatelet therapy.