In the 1980s, low doses of aspirin were proven to be effective to prevent heart attacks and strokes in patients who had previously suffered a heart attack or stroke. Subsequently many doctors and pharmacists were recommending that even healthy people take a low dose of aspirin every day. After all, why wait for a stroke or heart attack to happen if you could prevent one? And limited evidence suggested this may be beneficial.
However, things have changed significantly since the 1980s in healthcare. Evidence from the 1980s around cardiovascular medicines has been argued by many clinicians to be no longer relevant. We had (and still have) good evidence to suggest that aspirin was beneficial in preventing recurrent heart attacks and strokes, but the evidence of benefit in lower risk patients who had not already had a heart attack or stroke was unclear.
This set the scene for a large trial to determine whether aspirin truly does provide benefit for the average middle-aged person (if such a thing exists).
ASCEND, ARRIVE, and ASPREE are three landmark trials which included tens of thousands of patients, and were well designed to answer this question, and have put the question to bed. Aspirin does not provide overall benefit for the average middle-aged patient who has not had a heart attack or stroke.
Possible reasons for this surprising finding is that the cardiovascular health of our population is changing. Highly effective public health, pharmaceutical, medical and surgical interventions mean that less people are dying of heart attacks and strokes. So the benefits of aspirin are diminished.
Coupled with this is the fact that the ageing population is at higher risk of side effects such as stomach ulcers from aspirin. Therefore, the risk-benefit ratio of aspirin generally no longer supports its use in patients without established heart or blood vessel disease.
But this is not an isolated story. The story of aspirin is not unique. Fish oil supplements and aspirin have both been advocated for routine daily use to prevent heart attacks and strokes. Like aspirin, fish oil initially showed promise but recent large, well-designed trials on fish oil supplements have suggested minimal or no benefit in healthy middle-aged people. There are also numerous other examples in the pharmaceutical industry.
Can we learn a lesson from aspirin’s demise? I think so. Firstly, extrapolating trial data from older sicker patients to younger healthier populations is likely to cause unnecessary and even harmful overuse of pharmaceuticals. Secondly, trials of pharmaceuticals need to be repeated as populations and societies change.
So now that aspirin is dead, what should we ingest instead to prevent heart attacks and strokes? Well the answer to this lies more in what things we shouldn’t ingest, although that is much harder than merely swallowing a pill every day.
Note: if you are currently taking aspirin you should discuss this with your doctor or pharmacist before stopping, as aspirin is still very beneficial for some types of people.
Author: Karl Winckel is a Conjoint Associate Lecturer in the UQ School of Pharmacy. His research interests include clozapine use in treatment resistant schizophrenia- efficacy and adverse effects, anticoagulants and dosing in obesity, and the use of medicines in elderly people.
