If you’re an adult in your late 60s or 70s who’s physically healthy, mentally sharp and trying to stay that way, taking a daily low-dose aspirin probably won’t help that much, new research shows. Until…
If you’re an adult in your late 60s or 70s who’s physically healthy, mentally sharp and trying to stay that way, taking a daily low-dose aspirin probably won’t help that much, new research shows. Until now, there hasn’t been much guidance for healthy older people trying to weigh the possible preventive effects of aspirin against its known increased risks of bleeding.
On Sept. 16, findings from a large new study on preventive aspirin use appeared in the New England Journal of Medicine. The three-pronged clinical trial encompassed more than 19,000 older adults in the U.S. and Australia. Participants were living independently, without heart disease, dementia or diabetes when they enrolled between 2010 and 2014 in the study sponsored by the National Institute on Aging.
Participants, whose average age was 74, were randomly assigned to take either a daily low-dose 100 milligram aspirin (the international equivalent of a standard 81 mg baby aspirin) or a placebo. Over a roughly five-year period, researchers followed these healthy seniors to see whether regular preventive aspirin extended their lifespan free of disability or dementia. However, there was no real difference between people on aspirin and those on a placebo, results showed.
That finding is likely to disappoint many people. “As a geriatrician, one of the most common discussions I have with older adults that are healthy and in the community is around ways they can optimize not only how long they live, but the quality of life they have,” says study co-author Dr. Raj Shah, an associate professor of family medicine at the Rush Alzheimer’s Disease Center at Rush University Medical Center in Chicago. “Most older adults are very curious about being able to maintain their memory and thinking skills, and their physical mobility. And if they also get to live longer, that’s fine. But they want the combination.”
The higher risk of bleeding from regular aspirin use is already well-established. “As we get older, bleeding risk goes up,” says Dr. Randal Thomas , a preventive cardiologist in the department of cardiovascular medicine at the Mayo Clinic, who was not involved with the study. “For individuals above 75, we’ve known from past studies that they have such a high bleeding risk with aspirin, we particularly wouldn’t recommend aspirin anyway.” The new study helps confirm the need for caution with older adults, he says.
Colon cancer prevention is another reason many people take daily aspirin. “Studies over the last two decades have suggested that regular use of aspirin may have another important health benefit: decreasing the risk of developing or dying from some types of cancer,” according to the website of the National Cancer Institute. Cancer of the colon and rectum has the most evidence supporting long-term aspirin use for prevention. However, the new study didn’t find a cancer-prevention benefit for this particular group.
In a nutshell, these are results from the latest set of NEJM studies using a daily low-dose, coated aspirin. (Comparison figures represent events per 1,000 person-years, a measurement that accounts for the number of people and time spent in a study.)
— Healthy lifespan not extended. Over the study period, for study participants taking aspirin, the rate of dying, or developing dementia or a persistent physical disability, was 21.5 events, compared with 21.2 such events for participants who took a daily placebo. “Aspirin use in healthy elderly persons did not prolong disability-free survival over a period of five years,” researchers concluded.
— Major bleeding risk without heart benefit. Major bleeding episodes and cardiovascular events — fatal heart disease, heart attacks, strokes or hospitalization for heart failure — was another focus. For cardiovascular events, no significant difference was seen between participants who did or did not take daily low-dose aspirin. However, major bleeding episodes — notably gastric bleeding, hemorrhagic stroke and brain bleeding — showed a difference. Among participants taking aspirin, 3.8 percent suffered a major bleed compared with 2.7 percent of those on placebo pills.
— Mortality and cancer risk: no benefit. During an average follow-up period of nearly five years, 1,052 study participants died. To simplify the comparison numbers and put them into context, Shah says: “You would have to essentially treat 625 people for a year in order to get one excess death with aspirin.” Cancer-related deaths occurred in 3.1 percent of aspirin users versus 2.3 percent of participants on placebos.
Thomas calls the slight rise in all-cause mortality for participants on aspirin an “interesting finding” because it was tied to a slight worsening of cancer risk in this group. “Some studies in the past have shown aspirin therapy to decrease colorectal cancer [with] a higher dose of aspirin generally required to get that benefit,” he says. The unexpected new finding needs to be taken with some degree of caution, he adds: “We need to wait for other studies to confirm that.”
For middle-aged adults, some guidance already exists for decision-making on low-dose aspirin. The U.S. Preventive Services Task Force, an influential, national panel of medical experts, has made certain recommendations after thoroughly evaluating available scientific evidence.
For adults ages 50 to 59 and with at least 10 percent increased cardiovascular risk — but who are not at an increased risk for bleeding — the USPSTF recommends low-dose, daily aspirin to prevent cardiovascular disease and colon cancer.
Cardiovascular risk takes factors such as older age, being male, race and ethnicity, high cholesterol levels, high blood pressure, smoking and diabetes into account. Bleeding risk includes factors such as higher-dose and long-term aspirin use, a history of gastrointestinal ulcers or upper-GI pain, bleeding disorders and use of anticoagulant drugs, as well as uncontrolled high blood pressure, being male and older age.
For adults ages 60 to 69 who are at increased cardiovascular risk, without bleeding issues, the decision should be an individual one, according to the USPSTF. “Persons who place a higher value on the potential benefits than the potential harms may choose to initiate low-dose aspirin,” the panel summarizes.
However, for adults who are younger than 50 or older than 70, insufficient evidence did not allow the USPSTF to balance benefits and harms to make recommendations on starting daily aspirin. Authors of the new study hope their findings will help fill in the gaps for the older group.
“We knew that a lot of people were taking aspirin for unclear reasons because they read that it helps prevent heart disease in some people,” says Dr. Anne Murray, a senior researcher on the study team. “Very few people were aware of the bleeding complications among those who just started taking it on their own,” says Murray, who is the director of the Berman Center for Outcomes & Clinical Research, part of the HennepinHealth Research Institute, and a professor of medicine and geriatrics at the University of Minnesota.
In undertaking the study, Murray says, “We wondered if the benefits of aspirin — the blood-thinning and the anti-inflammatory effects — might extend beyond preventing cardiovascular disease to preventing brain disease.”
The “optimistic hypothesis,” Murray says, was that aspirin might help improve blood flow, not only by decreasing clot risk, but also by reducing inflammation within the brain’s small blood vessels and surrounding nerve cells. With that dual action from aspirin, the hope was that the risk of dementia as well as stroke might be reduced, therefore preventing disability related to both conditions. However, the study results didn’t bear that out.
Research on the possible preventive benefits of aspirin continues. The current study may be extended to look at even longer-term results, Murray says. In addition, researchers will investigate the genetics of the tumors that people with cancer developed during the newly published study, to see whether any interaction with aspirin played a role.
Aspirin dosage is another piece of the prevention puzzle, Thomas says. In diabetes research, he says, aspirin so far has not been shown to reduce the higher risks for heart disease and stroke faced by people with diabetes. “One thought is, perhaps in people with diabetes, we’re not using a high-enough dose of aspirin to make a difference,” he says. “So future studies are going to be exploring the most appropriate dose for the highest-risk patients.”
For now, Murray says, “There isn’t a clear reason for healthy older people who don’t have a history of heart disease to be on aspirin. There’s more potential for harm than good from being on aspirin, in the form of bleeding risks.”
If you’re currently taking aspirin as a preventive measure, it’s worth reconsidering, especially as an older adult. “We do think people who have started aspirin should really talk with their doctor,” Shah says. “Because in the end, it’s still a shared decision and an individual decision [made] with good medical advice.”