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When patients do it better than doctors: self management with warfarin

Ami Banerjee
Last edited 21st April 2010

Doctors and health professionals are often reluctant to put the ball in the court of the patient because that patients will not be able to cope with the responsibility. Last week a Cochrane review update was published about self-monitoring and self-management of warfarin therapy and challenges this concept. Warfarin is an anticoagulant (“blood-thinner”) and is used in several situations, including atrial fibrillation, pulmonary embolism, deep vein thrombosis and patients who have mechanical heart valves. In the latter case, warfarin therapy is for life. The major risk or side-effect of warfarin is bleeding, which can be life-threatening and so in order to check that the blood is not to thin, the “thickness” of the blood is checked regularly by the INR blood test, and the warfarin dose is adjusted accordingly.

Warfarin is a common drug in both primary care and hospitals and there are huge costs associated with INR testing in healthcare settings. The introduction of portable monitors (point-of-care devices) for the management of patients on warfarin allows self-testing at home. Patients who self-test can either adjust their medication according to a pre-determined dose-INR schedule (self-management) or they can call a clinic to be told the appropriate dose adjustment (self-monitoring).

The systematic review included 18 randomised controlled trials with nearly 5000 patients. The risk of death or a clot-related (thromboembolic) event was reduced by 36% and 50% respectively. Importantly, the benefit of self-management alone persisted, whereas, the benefit of self-monitoring was not statistically significant. In other words, it is not enough to let patients just measure their reading; the benefit comes when they are responsible for a treatment change based on that reading. The same paradigm of “self-management” versus “self-monitoring” needs to be tested in other conditions such as hypertension and diabetes in order to improve outcomes and to empower patients.

Low dose aspirin for primary prevention of CV event

Hi Ami,
Your research area of cardiovascular medicine is highly relevant to general practice. What evidence is there regarding the use of daily low-dose aspirin prevent cardiovascular event? Can you recommend any latest high-level evidence (published in 2009 or 2010) (e.g. Cochrane Reviews) that can help support this question - any two or three high level evidence will be great. I look forward to hearing from you.

Regards, Julian

Aspirin in primary prevention

Dear Julian
Thanks for the question and sorry for the delay in replying. I have written a couple of pieces on the blog about this very topic where the most recent best evidence is quoted:



The up-shot is that in patients who have not had CHD, stroke or peripheral vascular disease, there is no good evidence for aspirin in primary prevention. Moreover, even in at-risk populations, such as diabetics, the evidence is lacking for a benefit from aspirin in primary prevention.


some more links on this article

Warfarin: patient knows best

An Oxford-led review published last week in the Cochrane Library - that gold-standard source for the best evidence-based medical care - showed how empowering people at risk of blood clots to determine their own dose of anti-clotting drugs leads to a large drop in adverse events and deaths.......more at

Self-monitoring and self-management of oral anticoagulation
Cochrane podcast

Cheers Carl

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