I am often asked the question by patients and callers on my various radio segments as to whether they should be taking low dose aspirin on a daily basis to prevent heart attack and stroke. In fact, the evidence from secondary prevention trials (aspirin taken by people who have already had cardiovascular disease) suggests a reduction in recurrent events by around 25%.
Evidence over the last decade has also suggested up to a 30% reduction in a variety of common cancers in people who take daily aspirin. But, the primary prevention trials (people who do not have established disease) have produced quite variable results with some studies suggesting a possible benefit and others showing none at all.
The New England Journal of Medicine recently published the ASPREE trial. This was a trial of 19,000 people over the age of 70 with a follow up period on average just under 5 years, performed in Australia. All people were free of cardiovascular disease, dementia and considered healthy at the start of the trial and at the end of follow up there was no benefit in terms of reduction of cardiovascular disease and dementia from taking aspirin 100 mg daily compared with the placebo group.
This trial demonstrated an increase in significant bleeding and thus the conclusion of the trial is that aspirin should not be given as preventative therapy for people over the age of 70. This message is consistent with the other trials in younger people which again did not show any dramatic benefit.
So, who should be taking aspirin? I believe the evidence to date supports the use of low-dose aspirin in all people with established cardiovascular disease such as heart disease and stroke or people with very strong risk factors for heart disease, along with a high coronary calcium score. This is, of course, excluding people who are allergic to aspirin or have had a past history of significant gastrointestinal or cerebral bleeds. Aspirin (even the low-dose variety with a protective coating) is also associated with a significant increased risk for gastrointestinal reflux.
Thus, it is important to realise that aspirin is not a magic bullet although has been proven to be highly effective as a blood thinning agent for people with established disease. But, as with all aspects of medicine, one size does not fit all and if anyone reading this article does have established cardiovascular disease and has had no problems from the use of chronic aspirin therapy, it is important that you do not misinterpret this evidence thinking that there is no benefit for you. The message is purely for people without a history of cardiovascular disease or not at a particularly strong risk for this condition. As far as taking aspirin as a prevention for common cancers, although there is weak evidence, I do not believe the medical profession should be encouraging patients to use this for all the reasons I have said above.
As with all aspects of medicine, it is much more important to focus on key lifestyle principles than to believe that pharmaceutical therapy is the panacea that will keep you living for many years without disease.