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

• Vitamin K Antagonist (Drug): The vitamin K antagonists exert their anticoagulant effect through inhibition of the enzyme complex of vitamin K epoxide reductase subunit 1 with subsequent reduction of the gamma-carboxylation of certain glutamic acid molecules endpoints located on factors coagulation II (prothrombin), VII, IX and X and protein C or its cofactor protein S. This gamma-carboxylation has a significant bearing on the interaction of coagulation factors referenced with calcium ions. Without this reaction, blood clotting cannot be initiated. The dose must be adjusted to each patient at baseline and after regular basis, since the sensitivity to anticoagulants varies between individuals and can also vary throughout the treatment. For this, the Prothrombin Time (PT) is used and standardized ratio called International Normalised Ratio (INR).

Primary outcomes

• International Normalized Ratio (INR) Time in Therapeutic Range (TTR) [Up to 24 months]: Percentage of time within an INR range of 2-3 estimated using the Rosendaal method

Secondary outcomes

• Baseline thromboembolic risk based on the CHADS2 scale [Baseline]: CHADS2: Cardiac failure, Hypertension, Age, Diabetes, Stroke
• Baseline thromboembolic risk based on the CHA2DS2-VASc scale [Baseline]: CHA2DS2-VASc:Cardiac failure, Hypertension, Age ≥75, Diabetes, Stroke -Vascular disease, Age and sex category
• Baseline haemorrhagic risk based on the HAS-BLED scale [Baseline]: HAS-BLED: Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile INR, Elderly , Drugs/alcohol
• Changes in INR time in therapeutic range [Up to 24 months]: INR time in therapeutic range: percentage of time within an INR range of 2-3 estimated using the Rosendaal method
• Patient preferences with regard to anticoagulant treatment based on patients' questionnaires [Up to 12 months]
• Satisfaction with the anticoagulant treatment based on the Anti-Clot Treatment Scale (ACTS) [Up to 12 months]
• Adherence to the anticoagulant treatment: Morisky-Green test [Up to 12 months]
• Number and type of visits by patients to health professionals related to their anticoagulant treatment [Up to 12 months]
• Number of patients using anticoagulant treatment strategies [Up to 24 months]: Strategies: patients continuing vitamin K antagonists, patients with changes/adjustments to the dose of vitamin K antagonists and patients whose treatment is changed to direct action oral anticoagulants
• Number of patients treated according to clinical practice guidelines based on the Spanish Agency of Medicines and Medical Devices (AEMPS) therapeutic positioning report [Up to 24 months]
• Number of thromboembolic events in patients with inadequate anticoagulation management [Up to 24 months]
• Number of haemorrhagic events in patients with inadequate anticoagulation management [Up to 24 months]

Sex: All, ages: 18 Years to any

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.

• Bayer Study Director, Study director, Bayer