Published September 16, 2018, three new studies place in doubt safety of taking a daily aspirin for primary prevention. These studies were a part of the ASPREE trial, Aspirin in Reducing Events in the Elderly trial. It was a large scale study on the effects of taking aspirin on a preventative basis in older persons 70 years of age or older (65 years of age or older for black or Hispanic participants in the United States) and free at baseline of cardiovascular disease, dementia, or physical disability. So rather healthy older persons. 9525 participants were randomly assigned to receive 100 mg of aspirin per day and 9589 to receive placebo. The study took place in both Australia and the United States of America. The results were published in three separate articles in the New England Journal of Medicine and their results are rather astounding.
One study was on the effect of aspirin on disability free survival in the healthy elderly. The purpose of this part of the trial was to evaluate whether taking a daily aspirin would result in a life free from dementia or persistent physical disability. Among the adverse events they were investigating deaths contributed 50% of the total, dementia contributed 30%, and persistent physical disability 20%. When all the events (not just the first event to occur) were taken into account, the rates of dementia were similar in the two groups (aspiring and placebo) and there was no evidence of a preventative effect of aspirin on the rate of persistent physical disability. It was their finding that the use of low-dose aspirin in persons 70 years of age or older who did not have cardiovascular disease did not prolong disability-free survival.
Another study was on the effect of aspirin on cardiovascular events and bleeding in the healthy elderly. Same trial, same participants just looking specifically at a different outcome. Individual rates of heart attack, stroke, fatal cardiovascular disease, and hospitalization for heart failure were similar between the placebo and aspirin group. The rate of major adverse cardiovascular events was 7.8 events per 1000 person-years in the aspirin group and 8.8 events per 1000 person-years in the placebo group. The rate of major bleeding was 8.6 events per 1000 person-years in the aspirin group, as compared with 6.2 events per 1000 person-years in the placebo group. Their conclusion is the use of low-dose aspirin resulted in a significantly higher risk of major bleeding and did not result in a significantly lower risk of cardiovascular disease than placebo.
The third part of the trial was on the effect of aspirin on all causes of death in the healthy elderly. Again same participants but looking at whether or not aspirin reduced the instance of any cause of death compared to placebo. A total of 1052 participants (5.5%) died during the trial. The risk of death from any cause was 12.7 events per 1000 person-years in the aspirin group and 11.1 events per 1000 person-years in the placebo group. Cancer was the major contributor to the higher mortality in the aspirin group occurring in 3.1% of the participants in the aspirin group and in 2.3% of those in the placebo group. In their conclusions the authors state; “among healthy adults who did not have an indication for aspirin use and were predominantly 70 years of age or older at enrollment, all-cause mortality was apparently higher among those who received daily low-dose aspirin than among those who received placebo.”
It is a common occurrence for doctors to recommend older patients take aspirin as a primary preventative medication. This ASPREE trial was developed to examine how well taking aspirin in this way would benefit patients. What it found that there is little benefit to healthy older people and in fact there might be more risks in taking a daily preventative medication. I want to be clear that this study has everything to do with taking an aspirin for prevention when you are healthy. If you are taking a daily aspirin for its affect as a blood thinner these results might not apply to you. This study has similar findings as two others published earlier this year, the ARRIVE and ASCEND trials. Both found increased risks due to cardiovascular events.
My take, if you are healthy think very carefully about taking a daily aspirin as a primary prevention medication.