According to a recent VA study, patients taking warfarin, a widely used blood-thinning pill requiring careful dose monitoring produces similar outcomes whether the individual comes to a clinic or uses a self-testing device at home. The study involving nearly 3,000 veterans was sponsored by the VA’s Office of Research and Development in their Cooperative Studies Program. The findings published in the October 21, 2010 issue of the “New England Journal of Medicine” is good news for heart patients who live a distance from clinics or are homebound.
Traditionally, doctors, pharmacists, and nurses monitor patients who are taking warfarin, sold as Coumadin, over several clinic visits. They test how fast the blood clots and then the dose is adjusted accordingly. If the dose is too low, then the medication will not prevent blood clots and perhaps these clots will block the blood flow to the heart, brain or other areas of the body. Too high a dose can lead to dangerous internal bleeding.
Patients now have the option of tracking their own blood response at home, using blood analyzers known as International Normalized Ratio (INR) monitors. Patients do a finger stick where they apply a small amount of blood to a test strip and then feed the strip into the device. Patients can then call in the results to their provider and get advice on dose adjustments without coming to the clinic. In some cases, they can even set the proper dose of warfarin on their own.
The authors of the study expected home monitoring to work better than clinic monitoring, partly because self-testing can be done at home more frequently on a weekly basis as compared with the typical monthly schedule of the best clinic-based monitoring. As a result, off-target INR values can be adjusted more regularly and more quickly.
However, the VA study found little difference between weekly self-testing and monthly testing by clinic-based care teams in the measured outcomes, which are strokes, major bleeding incidents, and death.
The study did find that the self-testing at home may offer advantages in other ways. The self- testing moderately boosted the patients’ satisfaction with the medication and slightly increased the length of time that they were in the appropriate dose range. The main message of the study is that patients who are systematically monitored by whatever means are likely to have good outcomes.