Dosing accuracy of direct oral anticoagulants in an academic medical center
BACKGROUND/OBJECTIVE
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).
DESIGN
Retrospective analysis.
SETTING
Single academic medical center, July 1, 2014 to June 30, 2015.
PATIENTS
508 adult inpatients.
MEASUREMENTS
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.
RESULTS
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.
CONCLUSIONS
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. Journal of Hospital Medicine 2017;12:544-550. © 2017 Society of Hospital Medicine
© 2017 Society of Hospital Medicine
CONCLUSION
Healthcare professionals are prescribing DOACs in ways that differ from recommendations. These differences may reflect the older ages and reduced renal function of clinical populations relative to randomized clinical trial groups, but they could also potentially alter clinical efficacy. Our findings support the need to evaluate the appropriateness and dosing of DOACs at each encounter and to determine the outcomes of patients treated with lower than recommended doses of DOACs and the outcomes of DOAC-treated patients with bioprostheses or active malignancies.
Acknowledgment
The authors thank Tobias Schmelzinger for electronic data extraction and compilation and University of California San Francisco students Eduardo De La Torre Cruz (School of Pharmacy) and Carlos Mikell (School of Medicine) for assistance with data review.
Disclosure
Dr. Schwartz reports receiving personal fees from Bristol-Myers Squibb and Amgen and grants from Bristol-Myers Squibb and Pfizer, outside the submitted work. The other authors have nothing to report.
