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Anticoagulation self-monitoring.

The Problem

A 54-year-old woman presents to you with difficulty maintaining a therapeutic international normalized ratio (INR). She has a history of ileojejunal bypass 17 years ago complicated by recurrent episodes of bacterial overgrowth requiring frequent courses of antibiotics. She also has antiphospholipid antibody syndrome with recurrent deep vein thromboses and pulmonary embolisms necessitating a Greenfield filter placement, which has been complicated by venous stasis syndrome. She frequently has difficulty maintaining her INR in the therapeutic range due to the need for antibiotic therapy, and she is frustrated. You both have noticed a strong correlation between subtherapeutic INR levels and pain and swelling in her lower extremities. She has searched the Internet and made contact with a company that manufactures a home INR monitoring device. She requests that you fill out a medical necessity form which is to be faxed to the company. This is your first experience with these devices, because until now the cost has been prohibitive for most patients. You wonder if these devices reduce bleeding complications and increase the amount of time patients spend in the therapeutic range.

The Question

Does self-monitoring of anticoagulation with Coumadin increase readings in the therapeutic range and decrease bleeding complications, compared with clinic-based, outpatient point-of-care monitoring?

The Search

You go to PubMed ( and search "anticoagulation AND self-monitoring," limiting the search to randomized controlled trials. You see several RCTs and therefore limit the search to metaanalyses.

Our Critique

This review is of great help to clinicians trying to make sense of this exciting, emerging literature. However, it can be difficult to reach clear conclusions regarding outcomes because of potential differences between studies in the definitions of major and minor hemorrhage. Overall, the conclusions are favorable: Self-monitoring was associated with reductions in thromboembolic and major bleeding events; self-management was associated with reductions in thromboembolic events and death.

Patient Preferences & Clinical Decision

You decide that the patient is motivated and appropriate for self-monitoring. You complete the form and see if she can receive some financial assistance for the device.

C. Heneghan et al.

Self-monitoring of oral anticoagulation: a systematic review and meta-analysis. Review. Lancet 2006;367:404-11.

* Criteria for Study Inclusion: Published and unpublished controlled trials were included if they assigned patients randomly, compared the effects of self-testing or self-management of anticoagulation with control and dosage by a physician or anticoagulation management clinic, and/or reported clinical outcomes of thromboembolic and major bleeding events. Studies of both adults and children were included regardless of treatment indication with no language restrictions.

* Study Identification: EMBASE (1980-2005) and MEDLINE (1966-2005) were searched, limiting to randomized, controlled trials. The Cochrane Central Register of Controlled Trials and CINAHL (1982-2005) were also searched. Ongoing trials were identified using clinical trials registries, and experts in the field were contacted.

* Study Selection: All studies were assessed for methodological quality by three independent reviewers, and disagreements were resolved by discussion or by contacting authors.

* Outcomes: Primary outcomes were thromboembolic events, major bleeding episodes, death from all causes, and proportion of INR measurements within the therapeutic range. Secondary outcomes included testing frequency, minor bleeding events, and dropout rates.

* Results: The authors identified 14 randomized trials comparing self-monitoring with routine anticoagulation, with a total of 3,049 subjects. Patients were on anticoagulation for a variety of indications including mechanical valve (three studies), atrial fibrillation (two studies), and any indication (nine studies). Eight trials assessed the outcomes of self-management (self-monitoring and self-adjustment), and six assessed outcomes of self-monitoring only (no adjustment). Compared with controls, self-management and self-monitoring only decreased thromboembolic events (odds ratios 0.27 and 0.57, respectively; both groups combined, OR 0.45). However, among patients with mechanical valves, the effect on thromboembolic events was not significant (OR 0.60). For major hemorrhage, self-management did not reduce events, but self-monitoring only did (OR 0.56), compared with controls. For all-cause mortality, self-management reduced events (OR 0.37) but self-monitoring only did not, compared with controls. Eleven studies reported that the self-monitoring groups had improvements in mean INR results in the therapeutic range. Of the patients assigned to self-monitoring, 22% (range of 9%-43%) were unable to complete monitoring due to problems with the device, physical limitations, problems attending training, or failing the training assessment.


DR. EBBERT and DR. TANGALOS are with the Mayo Clinic in Rochester, Minn. To respond to his column or suggest topics for consideration, write to Dr. Ebbert and Dr. Tangalos at our editorial offices or e-mail them at
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Article Details
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Author:Ebbert, Jon O.; Tangalos, Eric G.
Publication:Internal Medicine News
Geographic Code:1USA
Date:Oct 15, 2006
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