Age Doesn't Matter Where Blood Thinners Are Concerned

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April 6, 2000 (Eugene, Ore.) -- A new study shows for the first time that blood thinning medications can prevent stroke safely in people with the common heart problem atrial fibrillation, even in those over the age of 80. This provides even more evidence that doctors are not prescribing blood thinners to the elderly as often as they should, and the researchers state that increasing the use of these medications could prevent a significant number of hospitalizations and deaths.

Atrial fibrillation is an irregular heartbeat that affects about 2 million Americans, according to the American Heart Association. Blood thinners, most commonly Coumadin (warfarin), are given to prevent blood clots that can form in the heart and be swept up into the circulatory system, and thus be carried to the brain and cause a stroke. Previous studies have shown definite benefit of Coumadin in people aged 65 to 75, but doctors have been unsure of its safety and effectiveness in older people, according to the authors. Thus, at least one-fourth of people with atrial fibrillation do not receive blood thinners, they write.


"The time has arrived when we ought to be prescribing Coumadin to people 80 years and older who have atrial fibrillation," says Brian F. Gage, MD, MSc, lead author of the study. "I am doing this in my own practice because I think the evidence is solid enough to say there is a benefit." Gage is an assistant professor of medicine at Washington University in St. Louis and director of the Barnes-Jewish Hospital Blood Thinner Clinic.

Coumadin is an effective blood thinner that must be used with caution. For this reason, it isn't used in patients who already have a tendency to bleed easily, such as those with bleeding ulcers, kidney failure, or liver disease, or who tend to fall a lot or have unsupervised dementia, Gage says.

Those who do use Coumadin must get a fingerprick blood test every three to four weeks, to be sure they have just the right amount of medication in their body. Too much can lead to potentially dangerous bleeding, and too little can lead to formation of a blood clot. For those who can't do this, Gage often recommends aspirin instead. "It is a weaker blood thinner, and we are not certain about the optimal dose, but I tell my patients who have atrial fibrillation and cannot use warfarin to take one adult aspirin each day," he says.


"Ours is the first study to find a significant benefit for [Coumadin] in a population with an average age of 80," Gage says.

"[The] study demonstrates that blood thinners have been underused in elderly people over 65 with atrial fibrillation and that this underuse has led to an increase in hospitalizations and deaths," the authors write.

"If I had atrial fibrillation, I would certainly want to discuss the reasons for and against taking [Coumadin] or aspirin with my doctor," says Richard Thomson, MD, who was not involved in the study. "Patient preferences are an important part of the shared decision-making process. This is particularly important for a medication like [Coumadin], where some patients may have strong feelings about the required monitoring process." Thomson is professor of epidemiology and public health at the University of Newcastle School of Medicine in England.

Thomson points out that "as patients get older, their risk of stroke increases." Although the problems associated with Coumadin may also increase with age, the benefits of use may be even greater in those who are older, he says. "In the absence of contraindications [such as easy tendency to bleed], we should be using warfarin in the elderly in the same way as in younger patients," he says.

Vital Information:

  • About 2 million Americans have atrial fibrillation, an irregular heartbeat that can cause blood clots. If a blood clot travels from the heart to the brain, it can cause a stroke.
  • Previous studies have shown that blood thinners like Coumadin are safe to use in patients aged 65 to 75. A new study shows the drug is safe to use in patients over 80, but overall, the therapy is underused.
  • Observers note it's important to discuss the use of blood thinners with your doctor. Some patients can't take potent blood thinners because they have other health conditions that would make the therapy unsafe, but they still may be able to use milder thinners like aspirin.
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