Aspirin therapy’s usefulness depends on risks

DEAR DR. ROACH >> Like many men, I have been taking 81-mg aspirin for decades. I recently saw a report indicating that not only is it not helpful, but that it actually can increase the risk of internal bleeding and the likelihood of death from cancer. What is your advice on the wisdom of continuing to take the aspirin? DEAR READER >> Aspirin has been used for 50 years or more to prevent heart attacks. Several studies in the 1980s and 1990s confirmed that aspirin is effective at preventing the first heart attack in men at average or high risk for heart disease. One trial was so persuasive that it was stopped early, as it was deemed unethical to allow the men on placebo to continue without being offered aspirin. The Women’s Health Study in 2001 showed that aspirin reduces risk of stroke in women.

However, aspirin has a well-known risk: It can cause bleeding, especially of the stomach and GI tract, but inside the brain as well. In comparing the risks and benefits, the studies showed that between 30 and 200 men need to be treated with aspirin for five years in order to prevent a heart attack, while one man in 100 or so will develop a bleed bad enough to require hospitalization or transfusion. In the Women’s Health Study, about 500 women needed to be treated for 10 years to prevent one stroke, while one woman in 25 developed bleeding. Of course, some bleeding (such as nosebleeds or blood in the urine) does not have the same effect on quality of life as a stroke.

Three trials recently have been published questioning the effectiveness of aspirin to prevent the first heart attack (I emphasize FIRST heart attack because everyone with a history of a heart attack should be on aspirin unless there is a reason for them not to be on it, such as a prior history of bleeding). One of these trials, the ASPREE study, showed that aspirin did not re- duce risk of a heart attack in people over 70, but did increase risk of bleeding. Aspirin also increased risk of dying from cancer in this study. This was unexpected. A review of all the previous trials showed that aspirin doesn’t increase or decrease risk of stroke in the first 10 years people take it, but after 10 years, risk of all cancer (but especially colon cancer) decreased by almost 50 percent. The ASPREE trial had follow-up for only five years.

Contact Dr. Roach at ToYourGoodHealth@med. cornell.edu.