Evaluating the Effect of Concomitant Azoles on Anticoagulant Prescribing Practices in Transplant Patients: A National Survey of Clinicians

<b>Background:</b> Patients undergoing transplantation experience higher rates of venous thromboembolism and non-valvular atrial fibrillation (NVAF) compared with the general population. Anticoagulation decisions in this patient population are complex. A national survey on direct-acting oral anticoagulant practices demonstrated significant heterogeneity, in the setting of drug-drug interactions. <b>Objective:</b> The aim of this study was to evaluate the anticoagulation practices of clinicians caring for solid organ transplant patients. <b>Methods:</b> A 15-question survey consisting of 7 demographic questions and 8 unique patient cases was distributed via email Listserv of several professional transplantation organizations. Each case question asked the participant to select an anticoagulant regimen depending on: (1) indication for anticoagulation, (2) renal function, and (3) drug-drug interactions. Participants selected one of the following options: apixaban, dabigatran, enoxaparin, rivaroxaban, warfarin, or write in an alternative option. Descriptive statistics were used to analyze survey results. <b>Results:</b> Fifty participants completed 4 or more (≥50%) of the case-based survey questions and were included in the analysis. Ninety-four percent of participants were pharmacists, representing 43 transplant centers. Fifty-one percent of responders preferred warfarin for the indication of NVAF. Apixaban was preferred in patients with new or previous deep vein thrombosis/pulmonary embolism (51%). Fifty-four percent of respondents preferred warfarin in questions in renal dysfunction. In scenarios involving a mild-moderate CYP3A4 inhibitor azole antifungal, 61% of respondents preferred apixaban, with 64% of those selecting a standard dose regimen (vs a reduced dose regimen). Participants preferred warfarin (57%) in scenarios with a strong CYP3A4 inhibitor. <b>Conclusion and Relevance:</b> The results of our survey demonstrated a high degree of variation when selecting anticoagulation strategies in complex clinical scenarios involving transplant patients.