Survey of Direct-Acting Oral Anticoagulants for Non-Valvular Atrial Fibrillation / 日本農村医学会雑誌

ABSTRACT

Direct-acting oral anticoagulants (DOAC) were approved for the prevention of cardiogenic embolism in non-valvular atrial fibrillation in recent years. However, the dosage of DOAC has to be reduced in patients with bleeding tendencies where the risk of hemorrhage is high, and dose reduction strategies differ depending on the type of DOAC. Therefore, we examined the dosage regimens of 4 DOACs (dabigatran, rivaroxaban, apixaban, edoxaban). Among 129 patients treated with DOACs, 85 received the standard dosage and 44 received non-standard dosage regimens. Among the non-standard dosage patients, 6 were taking a high dose (dose reduction was desirable) and 38 patients were taking a low dose (low dose is usually desirable). The low dosage group were significantly older and had a significantly lower CHADS2 score than that of the high dosage group. Hemorrhagic events occurred in 2 patients in the standard dosage group and in 3 patients in the low dosage group. Also, a thrombotic event occurred in only 1 patient in the standard dosage group. About 30% of the patients were on low dosage versus standard dosage. In practice, attending physicians tend to reduce the dose to avoid a hemorrhagic event particularly in elderly persons. However, a hemorrhagic event also occurred with low dosage in this survey. The validity and safety of dosages outside the limits of standard dosage have not been reported even though this dosage method is commonly used in clinical practice. Thus, more data should be accumulated from a large-scale cohort study to clarify this.