Faculty Articles

Feasibility of Extended-interval Follow-up for Patients Receiving Warfarin

Publication Title

Cardiovascular Therapeutics

Publisher

Hindawi

ISSN

1755-5922

Publication Date

6-1-2015

Keywords

adolescent, adult, aged, 80 and over, anticoagulants, atrial fibrillation, drug monitoring, female, humans, international normalized ratio, male, middle aged, pilot projects, prospective studies, risk factors, time factors, warfarin, young adult

Abstract

AIMS: The 2012 American College of Chest Physician Evidence-Based Management of Anticoagulant Therapy guidelines suggest an international normalized ratio (INR) testing interval of up to 12 weeks, rather than every 4 weeks, for patients with consistently stable INRs while taking vitamin K antagonists. We aimed to examine the feasibility of extended-interval follow-up in a real-world setting.

METHODS: Patients receiving stable warfarin therapy for ≥ 12 weeks at baseline began extended-interval follow-up with visits occurring at 6 weeks, 14 weeks, and every 12 weeks thereafter to a maximum of 68 weeks or until they were no longer suitable for extended-interval follow-up. A single INR excursion >0.3 from goal was permitted if a reversible precipitating factor was identified and the INR was expected to return to goal without dose adjustment. The primary outcome was the proportion of patients completing all study follow-up visits.

RESULTS: Of 48 patients enrolled, 47 had evaluable data. The most common indication for anticoagulation was atrial fibrillation/flutter (53.2%). At baseline, mean prior warfarin treatment duration was 6.7 ± 6 years and median number of weeks on a stable regimen was 24 weeks (IQR, 19-37.5). Eleven patients (23%) completed all study follow-up visits, whereas 17 (36%) did not maintain a stable INR past the 14-week follow-up.

CONCLUSION: A large proportion of patients with previously stable (≥ 3 months) INRs were not able to maintain stable INRs during extended-interval follow-up. More research is needed to identify patient characteristics predictive of success with extended-interval follow-up prior to broad implementation.

DOI

10.1111/1755-5922.12115

Volume

33

Issue

3

First Page

98

Last Page

103

Disciplines

Medicine and Health Sciences | Pharmacy and Pharmaceutical Sciences

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