Daily Aspirin Shows No Benefit for Healthy Older Adults
Heart diseases and stroke are the leading causes of death and disability in older adults in the United States. These are often caused by blood clots forming in the blood vessels that supply oxygen to the heart or the brain. Studies have found that aspirin can help some people prevent a second heart attack or stroke. It helps thin the blood to avoid further blood clots. There is also evidence that aspirin may help prevent a first heart attack or stroke in people who are at high risk for these conditions.
To investigate whether aspirin can benefit healthy older adults as well, a team of scientists led by Dr. John J. McNeil at Monash University in Melbourne, Australia and Dr. Anne M. Murray at Hennepin Healthcare in Minneapolis, Minnesota enrolled more than 19,000 older people in the ASPirin in Reducing Events in the Elderly (ASPREE) trial starting in 2010. The research was supported in part by NIH’s National Institute on Aging (NIA) and National Cancer Institute (NCI).
Most participants were aged 70 and older (65 and older for African-American and Hispanic individuals). None had dementia, a physical disability, or a previous heart attack or stroke at the start of the study. Participants were randomly assigned to receive either 100mg of aspirin per day or an inactive placebo pill that looked similar. Health outcomes were followed for an average of about 4.7 years. Initial findings were published online on September 16, 2018 in three papers in the New England Journal of Medicine.
The group taking aspirin had an increased risk of death; 5.9% of participants taking aspirin and 5.2% taking placebo died during the study. This was due primarily to a higher rate of cancer deaths. A small increase in new cancer cases was also seen in the group taking aspirin, but the difference may have been due to chance. Previous studies of aspirin haven’t seen these effects, so these results need to be explored further. Analysis of the cancer-related data from the trial is continuing.
The rates of major cardiovascular events—including coronary heart disease, nonfatal heart attacks, and fatal and nonfatal ischemic stroke—were similar in the aspirin and the placebo groups. So were the rates of physical disability and dementia.
Aspirin was associated with an increased risk of bleeding—a known risk of regular aspirin use. Clinically significant bleeding (hemorrhagic stroke, bleeding in the brain, gastrointestinal hemorrhages, or hemorrhages at other sites that required transfusion or hospitalization) occurred more in those taking aspirin (3.8%) than placebo (2.8%).
“Clinical guidelines note the benefits of aspirin for preventing heart attacks and strokes in persons with vascular conditions such as coronary artery disease,” says NIA Director Dr. Richard J. Hodes. “The concern has been uncertainty about whether aspirin is beneficial for otherwise healthy older people without those conditions. This study shows why it is so important to conduct this type of research, so that we can gain a fuller picture of aspirin’s benefits and risks among healthy older persons.”
“These initial findings will help to clarify the role of aspirin in disease prevention for older adults, but much more needs to be learned,” says NIA’s Dr. Evan Hadley. “The ASPREE team is continuing to analyze the results of this study and has implemented plans for monitoring participants.”
In the meantime, older adults should continue to follow the advice from their health care professionals about daily aspirin use.