Determinants of Oral Anticoagulants' Activity (ANTIGOAG)

Direct oral anticoagulants are changing clinical practices but a better knowledge of factors that may predict both drug response and risk of complications is need.

Anticoagulant activity is influenced by different factors. Because the biological activity is not easy to measure everywhere, it is important to clearly determine factors that are involved.

A cohort of 550 patients that receive either an anti-IIa or an anti-Xa will be recruited.

The primary objective is to determine clinical, biological and genetic determinants of anticoagulant activity.

This objective will be assessed through a multivariate logistic regression (separately for anti-IIa and anti-Xa) with anticoagulant activity as dependent variable.

Variables that will be included in the statistical model are those known or measured at the entry in the cohort such as :

• Clinical factors : age, sex, weight, dosage and time of the last dose
• Biological factors : serum creatinine level, plasma concentration of the drug
• Genetic polymorphisms :

Factor II and CES1 for anti-IIa drugs Factor X, CYP3, CYP3A4, CYP3A5 and ABCG2 for anti-Xa drugs.

By using the same statistical approach and the same variables, predictive factors of either hemorrhagic or thrombotic events will also be evaluated on the whole cohort. The occurence of hemorrhagic and thrombotic complications will then be assessed through a phone call every 3 months during a one-year follow-up.