Aspirin in low doses linked to increased risk of bleeding in the skull

Taking low doses of aspirin daily to prevent heart disease has been linked to an increased risk of bleeding in the skull, a report said Monday.

Published in the JAMA Neurology medical journal, the report stemmed from reviewing the results of 13 randomized clinical trials of more than 134,000 adults without heart problems who took either a low dose of aspirin or placebo daily.

Patients taking placebos had a 0.46% risk of experiencing an intracranial hemorrhage compared to 0.63% among people taking low doses of aspirin, the report found, meaning that people in the latter group suffered from bleeding in the skull in an additional two out of every 1,000 cases.

“The absolute magnitude of these adverse effects is modest, but clinically relevant,” the report’s authors wrote. “Given that the many individuals in the general population have a very low risk of atherosclerotic cardiovascular events, if low-dose aspirin is given universally, adverse outcomes from intracranial hemorrhage may outweigh the beneficial effects of low-dose aspirin.”

“Because the benefits of low-dose aspirin for primary prevention of cardiovascular events are not well established, and the outcomes of intracranial hemorrhage are often catastrophic, these findings suggest caution regarding using low-dose aspirin in individuals without symptomatic cardiovascular disease,” they concluded.

Conducted by a group of doctors led by Wen-Yi Huang of Chang Gung Memorial Hospital in Taiwan, the study was released less than two months since the American College of Cardiology and the American Heart Association released updated guidelines that advised adults older than 70 against regularly taking low-doses of aspirin, a painkiller and blood thinner, to prevent heart disease.

“Clinicians should be very selective in prescribing aspirin for people without known cardiovascular disease,” said Roger S. Blumenthal, a co-chair of the group that released the guidelines. “It’s much more important to optimize lifestyle habits and control blood pressure and cholesterol as opposed to recommending aspirin. Aspirin should be limited to people at the highest risk of cardiovascular disease and a very low risk of bleeding.”

The authors of Monday’s report defined low-dose aspirin as 100 milligrams a day or less. Bayer typically sells pills containing at least 325 mg aspirin — quadruple the strength of the company’s 81 mg baby aspirin.

In a statement, Bayer noted that the study failed to take into account the benefits of aspirin for patients who have previously suffered a heart attack of stroke.

“Aspirin continues to be the cornerstone treatment for the prevention of secondary cardiovascular events — and in fact, for those who have already experienced a heart attack, stroke or other cardiovascular event, discontinuing an aspirin regimen without a doctor’s guidance could increase the risk of another heart attack by 63 percent and an ischemic stroke by 40 percent. This new paper also does not question the potentially lifesaving role of aspirin during a suspected heart attack as directed by a doctor,” Bayer said.