Anticoagulant medications: Newer, easier to manage medications may not always be the best choice

In a study released online in April in the BMJ, a team of researchers from Mayo Clinic, and other collaborators, showed that for older patients, particularly individuals greater than 75 years of age, the risk of gastrointestinal (GI) bleeding is 3 to 5 times higher when taking newer anticoagulant medications dabigatran or rivaroxaban compared to when using warfarin.

One of the most common reasons people take anticoagulant medication -- which lessens the blood's tendency to clot -- is to reduce potential or severity of clotting complications in patients with atrial fibrillation or venous thromboembolism. People with atrial fibrillation and venous thromboembolism have a much higher risk of strokes, heart attacks and clots in the lungs and legs, which can result in disability or death.

Use of anticoagulants lessens the likelihood of stroke and other clotting complications, but brings a different set of risks, one of which is excessive bleeding due to reduced ability to form blood clots. Excessive GI bleeding in particular can itself be life threatening.

Warfarin has been in use since the 1950s, and is an effective anticoagulant. Because it is so powerful and long acting, users are required to have regular blood tests to monitor the effects.

The newer medications dabigatran and rivaroxaban are as effective as warfarin at preventing blood clots and reducing the risk of stroke and clotting complications, but do not require the regular monitoring. This convenience factor has resulted in an upswing in prescriptions for the newer medications as a replacement for warfarin.

However, convenience is not the only factor at play here, say the researchers.

"The new anticoagulants have really been popular with patients who have previously only had one choice of oral anticoagulant," says lead author Neena S. Abraham, M.D., "They greatly reduce the number of visits to the doctor for monitoring, and are much more convenient for patients. However, they may not be the right choice for everyone."

With so many treatment choices available, doctors and patients may have difficulty narrowing them down to 'the right choice.' This study helps pinpoint what appears to be a better choice for older individuals.

"In our study, by using the real-world, national data available from the Optum Labs Data Warehouse, we were able to determine that individuals over age 75 have a much higher risk of GI bleeds than younger patients, if using dabigatran or rivaroxaban instead of warfarin," says Dr. Abraham. "Our findings definitely point toward important age-related risk that merit consideration when doctors are making treatment recommendations. "

"We also saw that for patients under age 65, the newer agents appear to carry less risk of GI bleeds. At 65 this changes, and risk begins to increase until it exceeds the GI bleeding risk with warfarin at age 76 and older."

This a unique study, looking at adults of all ages who received anticoagulants, say the researchers, and thus has allowed a better understanding of the way these new drugs work for a broader group of people.

It is one of many projects ongoing in the Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery that seeks to improve the way patients experience health care.

The study's co-authors include: Sonal Singh, M.B.B.S., and G. Caleb Alexander, M.D., of Johns Hopkins; Herbert Heien, Lindsey Haas and Nilay Shah, Ph.D., of Mayo Clinic and Optum Labs, and William Crown, Ph.D., of Optum Labs.