Low dose daily aspirin is strongly recommended for patients who have had a heart attack or a stroke, together with patients who have symptoms of heart disease. [see references 1-3 below] In every hundred patients with heart disease who take aspirin, twenty or thirty heart attacks are likely to be prevented by aspirin in the next few years.
It is difficult however to summarise the value of aspirin in healthy people. Healthy people have a very low risk of a heart attack and so the actual number of attacks prevented is small. This means that the number heart attacks prevented will be low and may be close to the number of stomach bleeds caused by the aspirin.
In every thousand patients who take aspirin regularly, one or two will experience a bleed from the stomach. [So do read the section on aspirin and bleeding]
A study of 17,000 patients with heart disease found that a small daily dose of aspirin prevented three or four heart attacks or strokes each year.
Healthy people have a low risk of a heart attack, so the number of attacks which will be prevented by aspirin is very few. One estimate is that well over 100 healthy people would have to take aspirin daily in order to prevent one heart attack. and at the same time a bleeding event might be caused by the aspirin.
This however ignores the benefit of aspirin on the risk of cancer [see the section above on Aspirin and Cancer] When both heart disease and cancer are considered together, then aspirin taking by healthy older people is undoubtedly beneficial.[6 and 7]
Across the community, the number of heart attacks is declining steadily. In addition, a number of new drugs which will reduce the risk of a heart attack are now available. The most important of these are statins. Statins and aspirin work by quite different mechanisms within the body and there is no reason why they cannot be taken together – and remember, aspirin will also give protection against cancer.
In one of the largest reviews of trials of aspirin the authors pointed out that if a healthy person defers a decision about prevention of a vascular event by aspirin until he/she has some evidence of arterial disease, ‘…the first manifestations of disease might be a disabling of fatal event’.
People with diabetes have a greater than average risk of a heart attack, and the value of aspirin in these people is not well established. Recent research has however shown that the effect of a single aspirin tablet wears off rather rapidly in people with diabetes, and it has been suggested that effective protection may be achieved is aspirin is taken twice daily, rather than the more usual once a day.[8 and 9]
Aspirin is preventive and while the treatment of disease has been delegated to healthcare professionals, the preservation of health and the prevention of disease are the responsibility of each individual person. The prevention of heart disease by healthy living and by appropriate drugs is therefore ultimately the responsibility of each individual person. [See reference 10 below and do read the section on Healthy Living]
In one of the largest review of trials of aspirin the authors pointed out that if a healthy person defers a decision about prevention of a vascular event by aspirin until he/she has some evidence of arterial disease, ‘…the first manifestations of disease might be a disabling of fatal event’ [See reference 4 below]
Probably no drug has been as thoroughly evaluated as aspirin in the prevention of heart disease! It has been estimated that over 140 randomised trials of aspirin, and numerous overviews of trials have been published! Yet, because of the present decline in the risk of heart disease the main value of aspirin probably lies in its effect on the risk of cancer.
Aspirin was first made from a salicylate, a group of salts found widely in plants. Botanists tell us that salicylates have such a wide range of functions within plants, that much may yet be discovered about other benefits of aspirin to humans!
- Guidelines on cardiovascular disease prevention in clinical practice (version 2012). The fifth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular Disease Prevention in Clinical Practice. Eur Heart J. 2012;33:1635-701.
- Aspirin for the prevention of cardiovascular disease: US Preventive Services Task Force recommendation statement. Ann Intern med 2009;150:396-404.
- European Guidelines on cardiovascular disease prevention in clinical practice (version 2012): The Fifth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular Disease Prevention in Clinical Practice. Atherosclerosis 2012;223:1-68.
- Collaborative meta-analysis of randomised trials of antiplatelet therapy for prevention of death, myocardial infarction and stroke in high risk patients. Brit Med J 2002;324:71-86.
- Aspirin for primary prevention of coronary heart disease: safety and absolute benefit related to coronary risk derived from meta-analysis of randomised trials. Heart 2001;85:265-71.
- The role of aspirin in cancer prevention. Nat Rev. Clin. Oncol. 2012;9(5):259-267.
- Effect of including cancer mortality on the cost-effectiveness of aspirin for primary prevention in men. J Gen Intern Med May 2013 (epub ahead of print)
- The recovery of platelet cyclooxygenase activity explains interindividual variablility in responsiveness to low-dose aspirin in patients with and without diabetes. J Thromb Haemostasis 2012;10:1220-30.
- Primary and secondary prevention of cardiovascular disease in diabetes with aspirin. Diabetes & Vasc Dis Res. 2012;9:245-55.