Richard H. White, MD; Stephen A. McCurdy, MD, MPH; Hans von Marensdorff, MD; David E. Woodruff, MD; Lori Leftgoff, PA
Study Objective: To evaluate the efficacy and accuracy of monitoring prothrombin times at home.
Design: Randomized, prospective cohort study.
Setting: Outpatients discharged from a university hospital or a community hospital.
Patients: Fifty patients started on warfarin for the first time who demonstrated an ability to use the monitor and who had not achieved a stable response to warfarin in the hospital.
Intervention: Oral anticoagulation therapy managed using a portable prothrombin time monitor compared with specialized anticoagulation clinic care.
Measurements and Main Results: In the 46 patients who completed the 8-week study, the median percentage of time that patients in the home-monitor group (n = 23) were within a range equal to the target prothrombin ratio ± 0. 3, but always above 1.25, was 93%, compared with 75% for patients in the clinic group (n = 23) (P = 0.003). There was no significant difference between groups in the percentage of time above the therapeutic range; however, the percentage of time that patients were subtherapeutic was significantly greater in the clinic group (P < 0.001). There were no major thromboembolic or hemorrhagic complications in either group. Differences between home monitor measurements and corresponding clinical laboratory measurements using blood samples drawn within 4 hours of the home test were comparable to differences observed between measurements using two different clinical laboratory instruments.
Conclusions: Use of a portable prothrombin time monitor by patients at home is feasible and provides accurate measurements. Patients doing home monitoring achieve superior anticoagulation control compared with those receiving standard anticoagulation clinic care.
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White RH, McCurdy SA, von Marensdorff H, Woodruff DE, Leftgoff L. Home Prothrombin Time Monitoring after the Initiation of Warfarin Therapy: A Randomized, Prospective Study. Ann Intern Med. 1989;111:730-737. doi: 10.7326/0003-4819-111-9-730
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Published: Ann Intern Med. 1989;111(9):730-737.
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Print ISSN: 0003-4819 | Online ISSN: 1539-3704
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