ST. PAUL, Minn -- The rate of brain hemorrhages associated with blood thinning drugs quintupled during the 1990s, according to a study published in the January 9, 2007, issue of Neurology, the scientific journal of the American Academy of Neurology. In people over age 80, the rate increased more than tenfold.
Most of the increase is due to greater use of the drug warfarin, which is commonly prescribed to prevent blood clotting. Blood clots can lead to ischemic stroke, the most common type of stroke. An intracerebral brain hemorrhage is a stroke caused by bleeding in the brain.
The use of warfarin increased after studies showed it reduced the risk of stroke caused by blood clots for people with atrial fibrillation, a condition that causes irregular heart rhythm and becomes more common as people age.
"Warfarin is highly effective in preventing ischemic stroke among people with atrial fibrillation," said study author Matthew L. Flaherty, MD, of the University of Cincinnati. "For many people, the benefits of preventing ischemic stroke continue to outweigh the risk of a hemorrhagic stroke.
"Our findings should not discourage the use of warfarin when it's appropriate. Doctors can use these findings to make sure they are weighing the risks and benefits of warfarin use for their patients. For researchers, these results may stimulate efforts to develop safer alternatives to warfarin and better treatments for people with brain hemorrhages."
For the study, researchers identified all patients in the greater Cincinnati area hospitalized with a first-time intracerebral hemorrhage during three years: 1988, 1993-94, and 1999. In 1988, the annual rate of intracerebral hemorrhages associated with use of blood thinning drugs was .8 cases per 100,000 people. In 1999, the rate was 4.4 cases per 100,000 people. For people age 80 and older, the rate increased from 2.5 in 1988 to 45.9 in 1999.
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The study was supported in part by the National Institute of Neurological Disorders and Stroke.
The American Academy of Neurology, an association of more than 20,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as stroke, Alzheimer's disease, epilepsy, Parkinson disease, and multiple sclerosis. For more information about the American Academy of Neurology, visit www.aan.com.
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Neurology