Should older people in good health start taking aspirin to prevent heart attacks, strokes, dementia and cancer?
No, according to a study of more than 19,000 people, including whites 70 and older, and blacks and Hispanics 65 and older. They took low-dose aspirin – 100 milligrams – or a placebo every day for a median of 4.7 years. Aspirin did not help them – and could have done harm.
The risk of cardiovascular disease, dementia or disability was not reduced. And it increases the risk of significant bleeding in the digestive tract, brain or other sites that requires transfusion or admission to the hospital.
The findings were published Sunday in three articles in the New England Journal of Medicine.
A disturbing result puzzled the researchers, because it had not occurred in previous studies: a slightly higher mortality rate among those taking aspirin, mainly because of an increase in cancer deaths – not new cancer cases, but death from the disease. This finding requires further investigation before conclusions can be drawn, the authors warned. Scientists do not know what to think about it, especially as previous studies have suggested that aspirin may reduce the risk of colorectal cancer.
The researchers had expected that aspirin would prevent heart attacks and strokes in the study participants, so that the results came surprisingly – "the ugly facts that kill a beautiful theory," the Study Director John McNeil from the Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia, said in a telephone interview.
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The news could also be a shock to millions of people who have dutifully swallowed their daily pills like a potion to ward off all sorts of illnesses. Although there is good evidence that aspirin can help people who have already had a heart attack or stroke, or are at high risk of developing it, the value of the drug is not as clear to people with less risk, especially the elderly ,
The new report is the latest in a series of clinical trials that have tried to find out who really should take aspirin. A study published in August found no benefit in low-risk patients. Another found that aspirin can prevent cardiovascular events in people with diabetes, but that the risk of major bleeding outweighed the benefits.
A third study found that the dose is important and that heavier people need more aspirin to prevent heart attacks, strokes and cancer.
The latest findings apply only to people who are just like the study participants: in the same age groups and without a history of dementia, physical disability, heart attack or stroke. (Blacks and Hispanics have been included in the study more recently than whites because they are more risky than whites in dementia and cardiovascular disease.) In addition, most aspirin did not dose regularly before starting the study.
The message to the public is that healthy older people should not start taking aspirin.
"If you do not need it, do not start it," Dr. McNeil.
But those who use it regularly should not stop because of these findings, he said, recommending that they talk to their doctors first.
Dr. McNeil also emphasized that the new findings do not apply to people who have had heart attacks or strokes that typically cause blood clots. These patients need aspirin because it inhibits coagulation.
The study called Aspree is important because it answers the unanswered question as to whether healthy older people should take aspirin. Dr. Evan Hadley, director of the Department of Geriatrics and Gerontology at the National Institute on Aging, who helped pay for the research. The National Cancer Institute, Monash University and the Australian Government also paid. Bayer supplied aspirin and placebos, but had no other role.
"For healthy older people, there is still a good reason to talk with their doctors about what these results mean to them," said Drs. Hadley. "That's the average for a large group, a doctor can help figure out how it's done individually, and it's especially important for people who are already taking aspirin that is over 70. The study did not include many people who did and did not go into the question of whether to continue or stop. "
The The most widely used guidelines for the use of aspirin to prevent disease came in 2016 from experts from the United States Preventive Services Task Force. They recommend the drug for the prevention of cardiovascular disease and colorectal cancer in many people aged 50-59 who are at risk of heart attack or stroke for more than 10 percent in the next 10 years. (This risk, based on age, blood pressure, cholesterol, and other factors, can be estimated using an American Heart Association and American College of Cardiology online calculator.)
For the 60-69 year-olds with the same level of risk, the guidelines set out that it should be an individual decision as to whether aspirin should be taken.
But for people over 70, there is insufficient evidence in the guidelines for a recommendation.
Aspree was developed to fill the information gap for older people.
Rather than examining only a few ailments, the study also attempted to evaluate the impact of aspirin on "disability-free survival," ie, whether it could help older people to extend the time they remain healthy and independent.
"Preventive medicine focuses on helping older people how to keep them out of nursing homes, alive and healthy," Dr. McNeil. "Why should an older person take a drug if they can not keep them alive and healthy?" Many of the previous studies have looked at aspirin and heart disease, but many drugs do good and bad things, it does not seem to be enough to just look at one "
As of 2010, 16,703 people from Australia and 2,411 from the USA were included in the study. They were randomized to intake of low-dose aspirin (100 milligrams per day) or a placebo. That's a little over the widespread dose that most people take, 81 milligrams.
At a median follow-up of 4.7 years, the two groups had no significant difference in their rates of dementia, disability, or cardiovascular problems.
But those on aspirin were more likely to have a serious bleeding – it was 3.8 percent, compared to 2.7 percent in the placebo group.
Death rates also differed: 5.9 percent in the aspirin group and 5.2 percent in those taking placebos. Much of the difference was due to a higher rate of cancer deaths.
Dr. McNeil said his team could not explain the apparent increase in cancer deaths. They wondered if excessive bleeding could have contributed to deaths in cancer patients, but found no evidence. They will continue to follow the participants and examine tissue samples from cancer patients who have died.
Although it may not seem intuitive, he said the cancer finding does not exclude the possibility that aspirin may help to prevent colorectal malignancies. The protective effects may not emerge until people have taken aspirin for some time, longer than the average follow-up in the study.
Dr. McNeil, 71, does not take aspirin.