Dosing Accuracy of Direct Oral Anticoagulants in an Academic Medical Center

Direct-acting oral anticoagulants (DOACs) are increasingly used to prevent or treat thromboembolism. We conducted a study to compare how well initial DOAC prescribing for adult inpatients adhered to dosing recommendations approved by the US Food and Drug Administration (FDA).

Retrospective analysis.

Single academic medical center, July 1, 2014 to June 30, 2015.

508 adult inpatients.

DOAC prescriptions were evaluated to determine whether they met FDA-recommended dosing and administration according to patient age, weight, sex, race, kidney function, diagnoses, and concomitant medications.

DOACs were prescribed in 635 admissions (247 apixaban, 97 dabigatran, 291 rivaroxaban). The indication was atrial fibrillation/flutter in 465 admissions (8% with bioprostheses or valve repair), chronic deep vein thrombosis (DVT) in 67, acute DVT in 32, chronic pulmonary embolism in 23, acute pulmonary embolism in 19, DVT prevention after hip or knee surgery in 19, and non-FDA-approved indications in 10. Sixteen percent of orders for venous thromboembolic disease were for patients with active malignancy. Dosages not concordant with recommendations were prescribed for apixaban in 18% of admissions, for rivaroxaban in 14%, and for dabigatran in 7% (𝑃 = 0.04). Lower than recommended dosing was more common than higher than recommended dosing (𝑃 < 0.05). Half the deviations were continuations of outpatient dosing. Atrial fibrillation/flutter and post-hip or -knee surgery dosing deviations were more common than venous thromboembolic disease deviations (𝑃 < 0.001) but were not related to prescriber specialty.

DOAC prescribing recommendation deviations that can affect clinical efficacy were identified. Education and point-of-care decision support tools for improving dosing are needed, as are outcome data for patients who receive DOACs at lower than recommended dosing or for off-label indications.