Low-dose aspirin linked to increased risk of bleeding inside skull when taken daily, study suggests

For years, companies like Bayer have marketed low-dose Aspirin as a preventative treatment for cardiovascular disease, but new research shows that it increases the risk of bleeding in the skull when taken by people who do not already suffer from cardiovascular disease.

Aspirin works as a blood-thinner and can be used to treat dangerous blood clots that have the potential to cause heart attack or stroke. For those who have already suffered a heart attack or stroke, daily low-dose aspirin can help prevent another such attack from occurring, which offsets the risk of serious bleeding by about six to one, Harvard researchers determined.

For everyone else, scientists aren't so sure that the benefits of daily low-dose aspirin use outweigh the risks.

A team of researchers reviewed and analyzed 13 randomized clinical trials of low-dose aspirin use for primary prevention; 134, 446 patients participated in these trials, which occurred between January 1966 and October 30, 2018.

Researchers recorded levels of intracranial bleeding in participants and compared the differences between daily low-dose (less than 100 milligrams) aspirin users and a control group.

The researchers found that low-dose aspirin was associated with increased risk of any intracranial bleeding, but the greatest potential relative risk was for subdural or extradural hemorrhage, otherwise known as bleeding which occurs between the topmost and middle layers of membranes surrounding the brain.

There was a lower risk associated with intracerebral hemorrhage, or bleeding within the brain tissues, as well as with subarachnoid hemorrhage, or bleeding in the fluid-filled space between brain tissue and the first layer of membranes surrounding it.

The baseline patient characteristics most closely associated with intracerebral hemorrhage with low-dose aspirin use were low body mass index, and Asian race/ethnicity.

Anyone seeking to start or continue a daily low-dose aspirin regimen should consult with their doctor to find the safest course of treatment.