Prophylactic aspirin and public health

Low-dose aspirin prophylaxis is widely promoted for patients who have evidence of vascular disease, together with subjects who have a raised vascular risk score. The use of prophylactic aspirin by healthy subjects is however controversial on the grounds that the number of vascular events likely to be prevented can be close to the number of haemorrhagic episodes likely to be precipitated by the drug.1 A number of large-scale prospective studies have now given evidence that aspirin also reduces cancer incidence. Its use for this purpose is however controversial, again on the basis of the risk of haemorrhage.2 These risk/benefit evaluations appear to be based on the assumption that a bleed can be equated with a heart attack, a stroke or a cancer. With regard to both severity and sequelae this can clearly be challenged, and a comment in one of the major overviews of aspirin trials is apposite: ‘ … the alternative to primary prevention is deferral … .. [but] the first manifestation[s] of disease might be a disabling or fatal event’.3 Evidence from an overview of primary vascular randomized trials4 shows that the risk of death from gastrointestinal bleeding in subjects randomized to aspirin (4 per 100 000 subjects per year) is almost identical to that in subjects who had been randomized to placebo (5 per 100 000 per year).5 The report of one of the largest meta-analysis confirms this: ‘ … there were actually fewer fatal bleeds in participants allocated to aspirin than in the controls (nine vs twenty)’.6 This absence of a difference in mortality suggests that bleeds caused by aspirin are not the most serious. Furthermore, the long-term follow-up by Rothwell et al.,7 based on 51 randomized trials, shows a marked and significant decrease over the first few years in bleeding attributable to aspirin. On the basis of vascular risk alone, recommendations have been made,8–10 and challenged,11 that prophylactic aspirin be considered by subjects over the age of ∼50 years. For cancer prevention, Rothwell et al.12 recommend aspirin from the age of ∼45 years. In fact, population surveys show that many older people have made their decision and about one-third in people in Wales,13,14 and rather more in the USA15 state that they take aspirin regularly. McKee and Raine16 have pointed out, with reference to choices about health, ‘first choose your philosophy’. We believe that the appropriate philosophy in relation to health care is that while the treatment of disease has been delegated to health-care professionals, low-dose aspirin is prophylactic and whether or not to take it is ultimately the responsibility of subjects themselves—just as non-smoking, dietary choice and regular physical activity are a subject's own choice. The responsibility of health-care practitioners is therefore to ensure that adequate information on risks and benefits of all prophylactic measures is made widely available to enable people to make informed decisions about the protection of their own health. As a recent editorial commented: ‘a decision on whether or not a patient should take an aspirin requires a robust discussion of its benefits and harms … . [and] the elicitation of patient preferences’.17 Lenaghan et al.18 has urged that decision-makers at a local and national level should take time and make an effort to obtain informed comment from groups representative of the general public, and should not only listen to but should act on the voice of the public. A Citizens' Jury conducted a few years ago under the title: ‘My Health – whose responsibility?’ used low-dose aspirin as an example of a prophylactic medicine.19 The verdicts of 16 jurors, chosen to be representative of the general public, stated that public money should be spent on informing people about the risks and benefits of low-dose aspirin, and although at the time of that jury (2006) the available evidence on the reduction of cancer by aspirin was only suggestive, the jurors stated that the evidence on the risks and possible benefits of prophylactic drugs should be made available to the public ‘ … . even before there is agreement amongst doctors’ (our italics). The Wanless report on ‘Securing good health for the whole population’20 stated that health services in the UK are unsustainable in their current form unless members of the public are ‘fully engaged’ and take responsibility for their own health. The role of prophylactic aspirin, and how it might be handled within health care is being intensely debated in clinical circles and amongst epidemiologists. For people generally, the distinction between a ‘medicine’ such as aspirin and other preventive approaches is arbitrary—all are readily available consumer choices, and all carry potential, but uncertain risks and benefits. It is time that public health specialists engage with this issue to help people understand the evidence and ensure that members of the general public are equipped to make informed choices on issues of enormous potential to health.