Many heart-healthy older people take a daily baby aspirin out of a belief that it will help prevent a heart attack or stroke.
A major new study, published online Sunday in three articles in the New England Journal of Medicine (NEJM), now calls that common practice into serious question. It found that for older people with no history of heart attack, stroke or congestive heart failure taking a daily aspirin might do more harm than good.
In the study, a preventive regimen of daily aspirin did not lower the risk of having a heart attack or stroke, but it did significantly increase the risk of bleeding in the gastrointestinal tract or brain — bleeding severe enough to require hospitalization and/or blood transfusions.
The findings apply only to older adults who haven’t developed a blood-vessel-related problem, however. Other research has demonstrated that people with a history of heart attack or stroke do benefit from taking a daily aspirin because of aspirin’s anti-clotting effects.
“A lot of people read, ‘Well, aspirin is good for people who have heart problems. Maybe I should take it, even if they haven’t really had a heart attack,’ ” Murray added. But “for a long time there’s been a need to establish appropriate criteria for when healthy people — elderly people — need aspirin.”
The study involved 19,114 generally healthy volunteers (no history of cardiovascular disease, dementia or physical disability) living in Australia and the United States. Most were aged 70 or older, but the ages of some of black and Hispanic participants living in the United States were as low as 65. The age limit was lowered for those groups because blacks and Hispanics tend to be younger than whites when they have their first heart attack or stroke.
Based on their medical history, all of the participants were expected to live for at least another five years at the time they were enrolled in the study.
The participants were randomly assigned to receive either 100 milligrams per day of aspirin or a placebo pill. They were then followed for a median of 4.7 years. (The study was actually stopped earlier than had been intended when it became clear that the risks of aspirin for the participants outweighed the benefits.)
At the end of the study, the rate of cardiovascular disease between the two groups of participants was not much different: 9,525 of those taking the aspirin had developed cardiovascular disease compared to 9,589 of those taking the placebo.
The data also revealed essentially no difference between the two groups in their rates of developing disability and dementia.
But the rate of bleeding was significantly different. Among those taking aspirin, 8.6 percent experienced a major bleeding episode versus 6.2 percent of those taking the placebo.
“The use of low-dose aspirin resulted in a significantly higher risk of major hemorrhage and did not result in a significantly lower risk of cardiovascular disease than placebo,” the researchers conclude in one of the papers.
The study also reported that taking a daily aspirin did not help lower the risk of heart attack or stroke in people with high blood pressure or high cholesterol.
One of the more unexpected findings of the study was that people who took aspirin were slightly more likely to have died over the course of the trial from any cause (5.9 percent) than those who took the placebo (5.2 percent). This finding was surprising because almost half of those extra deaths were due to cancer, including colorectal and other gastrointestinal cancers. Previous research has suggested that taking daily aspirin offers protection against certain types of cancer, particularly colorectal cancer.
The study’s authors say, however, that the new study’s cancer findings may represent a statistical fluke and should be “interpreted with caution” until the data is analyzed more closely.
Talk with your doctor
So what should older healthy adults do with this new information about aspirin?
But he — and his study co-authors — also stress that anybody already taking aspirin should not quit using it before first consulting with their physician.
FMI: The study’s three papers can be found on the NEJM website.