Abstract
Purpose
Although warfarin has historically been the standard of care for preventing ischemic stroke in patients with nonvalvular atrial fibrillation (NVAF), the use of direct oral anticoagulants (DOACs) is rapidly increasing. In this study, we examined the demographic and clinical characteristics of patients continuing warfarin therapy and investigated reasons for warfarin continuation.
Patients and methods
Each study site consecutively registered 10 patients with NVAF who had been taking warfarin for at least 12 months. Demographic and clinical characteristics and international normalized ratio (INR) values were collected from medical records. Physicians responded to questionnaires exploring reasons for continuing warfarin therapy.
Results
Overall, 313 patients treated with warfarin were registered at 33 sites. Mean ± SD age was 76.4±9.6 years; 62.9% of patients were male. The proportion of patients with INR values in the therapeutic range was 74.6% and 48.8% among patients aged ≥70 years and <70 years, respectively. Over half of the patients (51.4%) had been advised to switch from warfarin to DOACs; the primary physician-reported reason for this recommendation was superior safety and effectiveness. However, patients reported continuing warfarin because of the high price of DOACs (47.2%) and long-term positive experiences with warfarin (31.7%). The remaining 48.6% of patients with NVAF had never been counseled by their physicians about DOACs as an alternative to warfarin. For 76% of these patients, physicians favored warfarin for medical reasons, such as impaired renal function and controlled INR, but in the remaining patients, medical reasons for continuing warfarin were lacking.
Conclusion
Approximately half of the patients in this study were informed of warfarin alternatives primarily for improved efficacy and safety, but elected not to change regimens because of the high price of DOACs and long-term positive experiences with warfarin. In the remaining half, physician preference or specific patient characteristics prevented a change in therapy.
Acknowledgments
The authors would like to thank the doctors participating in this study. We would like to acknowledge the contribution of Mebix, Inc. to this study, including site selection, site monitoring, study management, data management, and statistical analysis. We thank Ms Pearl Gomes from Cactus Communications KK for editing the manuscript. The study and editing of the manuscript were supported by Bristol-Myers Squibb KK and Pfizer Japan Inc.
Author contributions
All authors contributed toward study design, data analysis, drafting and revising the paper and agree to be accountable for all aspects of the work.
Disclosure
TI received research grants from Bristol-Myers Squibb KK, Daiichi Sankyo KK, Nippon Boehringer Ingelheim, honoraria and consulting fees (for speaker, writer and/or adviser) from Bayer Yakuhin Ltd., Bristol-Myers Squibb KK, Daiichi Sankyo KK, Nippon Boehringer Ingelheim, and Pfizer Japan Inc. MY received a research grant from Nippon Boehringer Ingelheim, honoraria and consulting fees from Bayer Yakuhin Ltd., Bristol-Myers Squibb KK, Daiichi Sankyo KK, Nippon Boehringer Ingelheim, and Pfizer Japan Inc. MK is an employee of Bristol-Myers Squibb KK. MI is an employee of Pfizer Japan Inc. The authors report no other conflicts of interest in this work.