Daily aspirin has five times higher risk of bleeding than first thought

13 June, 2012

Taking aspirin daily is linked to an increased risk of major bleeding much higher than previous research suggests, a large new study shows.

The study found aspirin was associated with a 55% increased risk of gastrointestinal bleeding and a 54% increased risk of intracranial bleeding after comparing almost 190,000 people taking low-dose aspirin to the same number of controls during a median follow-up rate of 5.7 years.

“Aspirin use was significantly associated with an increased risk of major bleeding,” the Italian researchers reported in JAMA.

The incidence of serious bleeds was five times higher in this real-world setting compared to previous randomised prospective clinical trials, they said.

The researchers also found that diabetes was the only subgroup not associated with a greater risk of bleeding, carrying a 36 percent increased risk of serious bleeds irrespective of aspirin use.

“Our study shows for the first time, to our knowledge, that aspirin therapy only marginally increases the risk of individuals with diabetes,” they wrote.

The accelerated platelet turnover in diabetes could explain the reduced incidence of adverse effects related to aspirin, the authors suggested, as well as its limited efficacy in preventing major cardiovascular events.

In an accompanying editorial, Professor Jolanta Siller-Matula from the University of Vienna said the study “underscores that the potential risk of bleeding should be carefully considered in decision making”.

“There is only a thin line between efficacy and safety and the reduction in ischemic events comes at the cost of increased major bleedings,” she said.

JAMA, June 2012. doi:10.1001/jama.2012.5034/ doi:10.1001/jama.2012.6152