New Analysis Demonstrates Benefits of Patient Self Monitoring in Treatment of Blood Thinners

Categories: Medical Messages

Risk of Blood Clots Substantially Reduced

In a report published in The Lancet, patient self-monitoring of their blood thinner treatment reduced the risk of blood clots by almost half (49%) compared with usual care.  This is based on a University of Oxford (UK) analysis of 11 different studies.

Randy Fenninger, president of the National Blood Clot Alliance(NBCA), said, “This new study confirms the wisdom of moving to self monitoring of INR, adding a strong scientific back up to the convenience that home testing offers.  I recently moved to home monitoring and have been very pleased by the convenience of this method of measuring the adequacy of my therapy to prevent a recurrence of the blood clots I experienced.  Home testing encourages more regular testing and greater compliance because it is so easy and convenient to do.  I hope this new study encourages patients to ask their physicians about changing to home monitoring.  The effectiveness of home testing that is demonstrated in this study should also persuade health plans to make it easier for people on long term warfarin therapy to have the monitoring covered.”

NBCA’s Medical and Scientific Advisory Board Chair, Jack Ansell, MD, (Chairman, Department of Medicine, Lenox Hill Hospital and Professor of Medicine, New York University School of Medicine) and co-author of the article, offered the following summary of the findings and perspective:

Oral anticoagulant therapy (blood thinner therapy) with warfarin (Coumadin®) in patients at risk for blood clots is complex and labor intensive for both the patient and the physician.  It requires frequent blood draws to assess and maintain the level of anticoagulation.  Patients can now perform these blood tests at home with a finger stick sample of blood with a specially designed instrument, similar to the way diabetics measure their blood sugar at home.

The recent study by Heneghan et al. in this week’s Lancet is an individual patient meta-analysis of a number of studies where the individual patient results from 11 randomized trials are aggregated together and analyzed as if the patient population made up an entirely new study.  This type of analysis enhances the statistical potential to arrive at more definitive results which might not be achieved in the individual studies.

Heneghan et al showed that patient home monitoring of the INR (the blood test used to measure the effect of Coumadin®) was associated with a 49% lower rate of recurrent or new blood clots overall, and a 66% lower rate in younger patients (less than 55 y.o.) compared to usual monitoring.  There was no difference in the rate of bleeding.   In elderly patients there was a lower mortality rate without an increased rate of adverse drug events indicating that treatment in older patients is both feasible and beneficial.

Of the 3 million patients in the United States currently on Coumadin®, home INR monitoring offers an easier, more effective, and just as safe method of managing one’s anticoagulation.  Currently only about 1% of patients in the US utilize home monitoring, thus, there is a great opportunity for improved care.

NBCA CEO, Alan Brownstein, MPH said that “More research is needed as this analysis did not demonstrate a major impact on mortality and the rate of bleeding complications was similar in those who did self monitoring and those who did not.  But overall, this analysis represents a mandate, in the US, for expanding the option of self monitoring to patients. This is for suitable patients with appropriate medical support, as pointed out by the authors of the analysis.”

The following is the release issued by The Lancet:

Patients who self-monitor their oral anticoagulation (blood-thinning) therapy with vitamin K antagonists (VKA) such as warfarin nearly halve their risk of developing thromboembolic events such as deep vein thrombosis, stroke, and heart attack compared with those receiving conventional care, according to a meta-analysis published Online First in The Lancet.

The therapeutic range for VKA is narrow and therefore requires regular monitoring and dose adjustment to prevent excessive anticoagulation that can result in major bleeding, or inadequate anticoagulation that can expose patients to the potentially fatal blood clots they are used to prevent.

Self-monitoring can improve the quality of anticoagulation and be more convenient for patients. Yet, the use of self-testing (patients test, but dosage is done by physicians) and self-management (patients test and adjust their own doses) has remained inconsistent both in and between countries, ranging from 20% of patients on anticoagulant therapy in Germany to just 1% of patients in the USA.

To provide more evidence of the benefit of self-monitoring, a team led by Carl Heneghan from the University of Oxford, Oxford, UK, pooled individual patient data from 11 randomized trials comparing self-monitoring of oral anticoagulation with conventional care.

They estimated the effect of self-monitoring on time to death, first major bleeding event, first thromboembolic event, and in important subgroups of patients such as the elderly and those with atrial fibrillation (a common and strong risk factor for stroke) and those with a mechanical heart valve.

Overall, self-monitoring reduced the risk of thromboembolic events by 49% compared with usual care. However, the rate of bleeding complications was similar in both groups and self-monitoring did not have a major effect on mortality.

The benefits of self-monitoring were particularly striking in individuals younger than 55 years in whom the likelihood of developing thromboembolic events was reduced by two-thirds and patients with a mechanical heart valve whose risk was halved.

Interestingly, self-monitoring lowered mortality and did not increase complications in very elderly patients who are at high risk of major bleeding, suggesting that age should not be a factor in determining eligibility for self-management.

The authors conclude: “Self-monitoring and self-management of oral coagulation is a safe option for suitable patients of all ages. Patients should also be offered the option to self-manage their disease with suitable health-care support as back-up.”

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