Millions of people take aspirin every day to lower their heart attack and stroke risk, but new research may change some of that thinking.

Daily aspirin use was associated with a higher-than-expected increase in the risk for major bleeding in an Italian study published this week in the Journal of the American Medical Association.

The risk for serious bleeds was five times higher than has been reported in clinical trials of daily low-dose aspirin, says researcher Antonio Nicolucci, MD.

He noted that while daily aspirin therapy has been proven to lower the risk for a second heart attack or stroke in people who have already suffered one, the treatment's usefulness for preventing a first heart attack or stroke is not so clear.

"People with a moderate-to-high risk for having a major cardiovascular event probably benefit from aspirin therapy, but the risks may outweigh the benefits for people with a lower risk," Nicolucci tells WebMD.

Diabetes Linked to Bleeding Risk

Nicolucci and colleagues set out to examine how daily aspirin use affected the risk for major bleeds in people with and without diabetes.

To do this they followed close to 186,000 adults on daily low-dose aspirin therapy and the same number of people who did not take aspirin regularly for an average of about six years.

During the follow-up, about 2,500 people were hospitalized for bleeding in the brain and close to 4,500 were hospitalized for gastrointestinal bleeding.

The researchers were surprised to find that patients with diabetes had a 36% increased risk for these potentially life-threatening bleeding episodes even when they did not take aspirin. Aspirin use did not appear to influence this risk for people with diabetes one way or another.

Diabetes is a major risk factor for heart attack and stroke, and low-dose aspirin is recommended for most diabetic men over age 50 and diabetic women over 60 when other heart disease and stroke risk factors are present.

American Heart Association past president Robert Eckel, MD, says more study is needed to understand the impact of diabetes on bleeding risk.

"The finding that diabetes in and of itself conveys a risk for bleeding is a new one," he tells WebMD.

Statins May Lower Bleeding Risk

The study also suggested a protective role for cholesterol-lowering statin drugs against bleeding.

Taking statins was associated with a lower risk for both gastrointestinal and brain bleeding.

Nicolucci says the study's findings highlight the importance of considering an individual patient's cardiovascular and bleeding risk when aspirin therapy is being considered.

"Many things influence bleeding risk, including the use of anti-inflammatory pain drugs, other drugs, and even alcohol and smoking," he says.

Eckel, a professor of medicine, physiology, and biophysics at the University of Colorado in Denver, echoes the researcher's sentiments.

"We have known for some time that aspirin therapy is associated with a higher risk for bleeding," he says. "That is why it is so important for patients to understand their bleeding risk before starting treatment."

SOURCES:DeBerardis, G.D. Journal of the American Medical Association, June 6, 2012.Antonio Nicolucci, MD, Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy.Robert H. Eckel, MD, professor of medicine, physiology, and biophysics, University of Colorado, Denver; past president, American Heart Association.News release,Journal of the American Medical Association.American Diabetes Association: "ACC/AHA/ADA Joint Scientific Statement."

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