Aspirin in the primary prevention of vascular disease

Abstract

The media coverage of the conclusions of the paper by the Antithrombotic Trialists' (ATT) Collaboration1Antithrombotic Trialists' (ATT) CollaborationAspirin in the primary and secondary prevention of vascular disease: collaborative meta-analysis of individual participant data from randomised trials.Lancet. 2009; 373: 1849-1860Summary Full Text Full Text PDF PubMed Scopus (2674) Google Scholar, 2Sanmuganathan PS Ghahramamani P Jackson PR Wallis EJ Ramsay LE 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: 265-271Crossref PubMed Scopus (367) Google Scholar is a cause for concern. Once again, information relating to a major policy area is communicated to the public ahead of any preparation or prepared response from the profession. Once again we will find variation in patients' treatment being driven by media interpretation rather than by clinical judgment. In reference to the primary prevention part of the study, the paper does not say what dose of aspirin was being used and whether this was the same in all trials or whether the relation between the benefits and side-effects was related to the dose. The paper explicitly states that the subgroup with the highest risk was too small for statistical analysis. The vascular event rate in the placebo group was 0·57% per year—a quarter of that expected in the high-risk groups (ie, those with a risk of cardiovascular disease of >20% over 10 years). The paper therefore does not answer the question of whether aspirin should be used in primary prevention for high-risk groups, but mischievously casts doubt in the minds of doctors and fear into the minds of patients. So should primary-care physicians be influenced by research that influences by innuendo, or follow the judgment of Sanmuganathan and colleagues2Sanmuganathan PS Ghahramamani P Jackson PR Wallis EJ Ramsay LE 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: 265-271Crossref PubMed Scopus (367) Google Scholar (not cited in the ATT Collaboration's meta-analysis,1Antithrombotic Trialists' (ATT) CollaborationAspirin in the primary and secondary prevention of vascular disease: collaborative meta-analysis of individual participant data from randomised trials.Lancet. 2009; 373: 1849-1860Summary Full Text Full Text PDF PubMed Scopus (2674) Google Scholar incidentally) who conclude that the benefits of 75 mg aspirin in primary prevention outweigh the side-effects in people with a cardiovascular disease risk of greater than 15% over 10 years? What do we advise our patients now? I declare that I have no conflicts of interest. Aspirin in the primary prevention of vascular disease – ATT secretariat's replyFor secondary prevention of occlusive vascular disease, low-dose aspirin (or some other antiplatelet regimen) is of definite net benefit, since the absolute reduction in recurrence substantially exceeds any increase in serious bleeds (ie, haemorrhagic stroke or major gastrointestinal haemorrhage).1 For primary prevention, however, among patients with no relevant history of disease, the proportional reduction in occlusive stroke or myocardial infarction may well be similar to that in the secondary prevention trials, but the absolute reduction is much smaller, and the balance of benefit and haemorrhagic risk is therefore less definite. Full-Text PDF