BOSTON (Reuters) - Two drugs are not always better than one when it comes to using blood thinners to treat clogged arteries in the legs, U.S. researchers reported on Wednesday.
They found that adding a blood thinner such as warfarin to daily clot-preventing drugs such as aspirin is no better — and sometimes more dangerous — for preventing heart attacks, strokes and other circulatory problems in people with peripheral artery disease.
About 1 in 16 people over 40 have some degree of clogging in the arteries outside their heart. The 8.5 million in the United States who do face a higher risk of death from heart disease.
Doctors have known for years that antiplatelet drugs such as aspirin reduce that risk.
Because blood thinners are used to treat clots that develop from peripheral artery disease, researchers thought adding them to the mix might cut the risk further.
The new study in the New England Journal of Medicine shows that such hopes are unfounded.
Results from 2,161 volunteers treated at 80 medical centers in seven countries demonstrate that adding the second drug had virtually no effect on the risk of heart attack, stroke, a severe clot outside the heart, or death from any type of heart disease.
The rates were 15.9 percent in the combination group and 17.4 percent in the antiplatelet-only group, an insignificant difference.
However, 4 percent of the people getting combination therapy suffered life-threatening bleeding, compared with just 1.2 percent getting an antiplatelet drug.
“Treating 1,000 patients with combination therapy as compared with antiplatelet therapy alone for three years would lead to 24 fewer cardiovascular events but 28 more episodes of life-threatening bleeding, resulting in a net increase in serious adverse outcomes,” said the research team, led by Sonia Anand of McMaster University in Hamilton, Ontario.