Physician perceptions and use of reduced-dose direct oral anticoagulants for extended phase venous thromboembolism treatment.

Background: The direct oral anticoagulants (DOACs), apixaban and rivaroxaban, have been studied for extended-phase treatment of venous thromboembolism (VTE). Yet, scant evidence exists surrounding clinician practice and decision-making regarding dose reduction. Aims: Report clinician practice and characteristics surrounding dose reduction of DOACs for extended-phase VTE treatment. Methods: We conducted a 16-question REDCap survey between July 14, 2021, and September 13, 2021, among ISTH 2021 Congress attendees and on Twitter. We explored factors associated with dose reduction using logistic regression. We used k-means clustering to identify distinct groups of dose-reduction decision-making. Random forest analysis explored demographics with respect to identified groups. Results: Among 171 respondents, most were attending academic physicians from North America. Clinicians who treated larger volumes of patients had higher odds of dose reduction. We identified five clusters that showed distinct patterns of behavior regarding dose reduction. Cluster 1 rarely dose reduces and likely prescribes rivaroxaban over apixaban; cluster 2 dose reduces frequently, does not consider age when dose-reducing, is least likely to temporarily reescalate dosing, and prescribes apixaban and rivaroxaban equally; cluster 3 dose reduces <50% of the time, and temporarily reescalates dosing during increased VTE risk; cluster 4 dose reduces frequently, temporarily reescalates dosing, and is most likely to prescribe apixaban over rivaroxaban; and cluster 5 dose reduces most frequently, and takes the fewest risk factors into consideration when deciding to dose reduce. Conclusions: Most clinicians elect to dose-reduce DOACs for extended-phase anticoagulation. The likelihood of a clinician to dose reduce increases with volume of patients treated. Clinician prescribing patterns cluster around VTE risk factors as well as reescalation during high-risk periods.