Control of INR Test Results Are Key to Patient Safety

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Friday, October 10, 2008

PTINR.com Staff

An INR of 3.0 or less was found to reduce the risk of larger bleeding events for patients taking warfarin

Warfarin, brand named Coumadin®, is prescribed for eligible patients at risk for developing dangerous blood clots. The most common side effect of warfarin is bleeding, and the risk of bleeding is closely related to warfarin (Coumadin ®) dose.¹

A study conducted by researchers at the University of Cincinnati Academic Health Center, and published in the medical journal Neurology, highlights the importance of careful warfarin management.

The study included 251 patients who had experienced a bleeding event in the brain. Only 20% of the patients were taking warfarin. Investigators analyzed these 51 patients to determine whether INR levels affected the severity of the bleeding event, measured by blood volume.²

The year-long study found that warfarin patients who were well managed and who maintained INR values in target range are not at higher risk for a bleeding event in the brain than those not taking warfarin. “Warfarin users were not more likely to have IVH (intravascular hemorrhage) than other patients (not taking warfarin).”   However, the authors did find that larger blood loss was more common in warfarin patients with INR test results greater than 3.0.²

Patients should work with their healthcare team to improve control of warfarin therapy. Better warfarin management can be achieved with ongoing patient education to enhance understanding of the potential for dietary and/or medication interactions, as well as with more frequent INR testing.

Weekly INR testing is a strategy that has been shown to improve the control of warfarin, and is supported by a review of 14 clinical studies that was published in the medical journal Lancet. In fact, weekly testing improves time in range to 85%, compared with only 50% for monthly testing. Patient self-testing is complimentary to routine care and requires a physician’s prescription. Medicare covers the cost of weekly patient self-testing, following the completion of face-to-face training.