Low Dose Direct Oral Anticoagulants in Patients With Atrial Fibrillation Tied to Higher Bleeding Incidence vs Standard Doses

Jun 20, 2024

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Patients with atrial fibrillation (AF) on low doses of direct oral anticoagulants (DOACs) have more bleeding episodes than those on standard doses, according to a study published online June 6 in Blood Advances.

Gualtiero Palareti, M.D., from Fondazione Arianna Anticoagulazione in Bologna, Italy, and colleagues collected venous blood at 15 to 30 days after DOAC initiation in patients with AF who were then followed for one year to examine the occurrence of major and clinically relevant nonmajor bleeding. The analysis included 1,657 patients treated with standard DOACs and 700 with low-dose DOACs.

The researchers found that 50 bleeding events were recorded during 1,606 years of follow-up (3.11 percent per patient-year). In the highest C-trough standardized values activity class, 15 bleeding events (4.97 percent per patient-year) occurred (>0.50) versus 35 events (2.69 percent per patient-year) in those with values in the two lower classes. Increased bleeding risk in the first three months of treatment was seen with increasing DOAC levels and low-dose DOAC use. Among patients receiving low doses, 19 percent had standardized activity values in the highest class. For low-dose DOACs, more bleeding occurred (4.3 percent per patient-year) compared with the standard dose (2.2 percent per patient-year).

“Early measurement of DOAC levels in AF patients identified many subjects with high activity levels despite the low doses use and had more bleeding risk during the first three months of treatment,” the authors write.

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