Patient Satisfaction With Extended International Normalized Ratio Follow-up Intervals in a Veteran Population

Ann Pharmacother. 2020 May;54(5):442-449. doi: 10.1177/1060028019889414. Epub 2019 Nov 21.


Background: For highly stable warfarin patients, limited data exists regarding patient satisfaction on extended international normalized ratio (INR) follow-up intervals and how this population compares with patients on a direct oral anticoagulant (DOAC). Objective: To assess the impact on patient satisfaction of extending INR follow-up intervals. Methods: Veterans on stable warfarin doses had extended INR follow-up intervals up to 12 weeks in a single-arm prospective cohort study for 2 years. This analysis included participants who completed at least 2 Duke Anticoagulation Satisfaction Scales (DASS). The primary outcome was the change in the DASS. A focus group described participant experiences. Participant satisfaction was compared to patients on a DOAC. Results: Of the 51 participants, 48 were included in the warfarin extended INR follow-up group. Compared with baseline, the mean DASS score (42.9 ± 12.08) was worse at 24 months (46.82 ± 15.2, P = 0.0266), with a small effect size (Cohen's d = 0.29). The 8 participants in the focus group were satisfied with the extended INR follow-up interval but would be uncomfortable extending follow-up past 2 to 3 months. The extended INR follow-up interval study had similar DASS scores as the 33 participants included on DOAC therapy (46.8 ± 15.1, P = 0.9970) but may be limited by differing populations using DOACs. Conclusion and Relevance: For patients currently stable on warfarin therapy, extending the INR follow-up interval up to 12 weeks or changing to a DOAC does not appear to improve patient satisfaction.

Keywords: anticoagulants; drug monitoring; factor Xa; international normalized ratio; patient satisfaction; thrombin; warfarin.