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Review: self monitoring increases the efficacy and safety of anticoagulant therapy

Clinical impact ratings GP/FP/Primary care IM/Ambulatory care Internal medicine Haematology

Key Words: anticoagulants • heparin • warfarin • self administration

METHODS
Data sources Medline, EMBASE/Excerpta Medica, and CINAHL (2005); Cochrane Central Register of Controlled Trials; Cochrane Library (issue 2, 2005); UK National Research Register; Trials Central; bibliographies of retrieved studies; manufacturers of home monitors; and experts in the field.

Study selection and assessment randomised controlled trials (RCTs) that compared self testing (only) or self management (testing and dose adjustment) with management by healthcare professionals (control group) in adults or children who were receiving oral anticoagulation therapy for any indication. 14 RCTs (n = 3049, mean age range 42–75 y) met the selection criteria. Quality assessment of individual trials included randomisation, allocation concealment, blinding of outcome assessors, use of intention to treat analysis, and follow up. In the control group, management was provided by primary care physicians in 8 RCTs and by specialised anticoagulation clinics in 6 RCTs. Duration of the studies ranged from 2 to 24 months.

Outcomes thromboembolic events, major bleeding episodes, all cause death, proportion of international normalised ratio (INR) measurements within target range, and testing frequency.

MAIN RESULTS
Thromboembolic events, major bleeding episodes, and death occurred less frequently in the self monitoring group than in the control group (table). The self monitoring group had a higher proportion of tests with mean INR within the target range in 7 of 11 RCTs and a greater proportion of time within the target range in 2 of 7 RCTs. The self monitoring group tested 2–5 times more frequently than the control group, with the ratio increasing in studies with longer duration.

CONCLUSION
In patients receiving oral anticoagulant therapy, self monitoring reduces risk of thromboembolism, major haemorrhage, and death compared with management by healthcare professionals.

Abstract and commentary also appear in ACP Journal Club.

FOOTNOTES
For correspondence: Dr C Heneghan, University of Oxford, Oxford, UK. carl.heneghan{at}dphpc.ox.ac.uk

Source of funding: no external funding.

Commentary

Jefferson Medical College, Philadelphia, Pennsylvania, USA

Maintaining oral anticoagulation with vitamin K antagonists remains one of the more challenging aspects of medicine. To meet this challenge, the use of both anticoagulation clinics and point of care monitors by providers has clearly improved anticoagulation control. Just as diabetic patients have learned that self monitoring can improve control of their disease, patients undergoing anticoagulation and their providers have learned that self monitoring using point of care prothrombin time devices can improve anticoagulation control.¹ Well over 100 000 Europeans and an increasing number of Americans are self monitoring their oral anticoagulation.

Heneghan et al reviewed 14 RCTs of self monitoring compared with care provided by anticoagulation clinics or the patient’s primary care physician. Self monitoring resulted in increased time of INR in the therapeutic range, fewer bleeding and thromboembolic events, and lower mortality. Fewer complications occurred whether patients self tested and physicians adjusted the dose, or the patients both self tested and self adjusted the dose. The favourable findings of self monitoring were also evident in other reviews.²

Despite these improved outcomes, challenges remain for the wide scale adoption of self monitoring. Suitable patients are those who require long term anticoagulation, are well motivated, and have sufficient manual dexterity and adequate vision.³ Such patients should receive thorough training by a healthcare provider who has a clear understanding of the equipment and the pharmacokinetics of warfarin. Another challenge is reimbursement, which varies by country. Currently in the US, Medicare only reimburses patients and physicians for anticoagulation monitoring associated with mechanical valves. Findings from the review by Heneghan et al should improve the reimbursement outlook for patients who have other indications for long term anticoagulation.

REFERENCES

1. Ansell JE, Hughes R. Am Heart J 1996;132:1095–100.[CrossRef][Medline]
2. Siebenhofer A, Berghold A, Sawicki PT. Thromb Haemost 2004;91:225–32.[Medline]
3. Ansell J, Jacobson A, Levy J. et al. Int J Cardiol 2005;99:37–45.[CrossRef][Medline]

This Article Extract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Add article to my folders Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Spandorfer, J. Search for Related Content PubMed PubMed Citation Articles by Spandorfer, J.