Aspirin use for primary prevention 'not justified'
By Nigel Praities
GPs should ignore guidelines recommending the routine use of aspirin in patients at high cardiovascular risk, claim the authors of a major analysis of 22 studies.
After carrying out the largest meta-analysis to date – published in the latest edition of the Lancet – they concluded the use of low-dose aspirin in those without cardiovascular disease was ‘not justified'.
The Antithrombotic Trialist's Collaboration group found the modest benefit of aspirin offset by an increase in the risk of a major bleed.
Their analysis of data from 95,000 patients from primary prevention trials found a 18% reduction in the risk of a major coronary event with aspirin compared with controls, driven by a 23% reduction in non-fatal myocardial infarction.
But aspirin was also associated with a 54% rise in extracranial bleeds compared with controls.
The authors say this conflicting evidence meant recommendations from NICE and Joint British Societies guidelines to use aspirin in those at high cardiovascular risk should be changed.
NICE guidelines for Type 2 diabetes – updated last May – recommend GPs use low-dose aspirin, 75mg daily, in patients over 50 years with controlled blood pressure or those under 50 years of age with significant cardiovascular risk factors.
Professor Colin Baigent, professor of epidemiology at the University of Oxford, said guidance advocating the routine use of aspirin in all apparently healthy individuals was not justified.
‘Drug safety really matters when making recommendations for tens of millions of healthy people. We don't have good evidence that, for healthy people, the benefits of long-term aspirin exceed the risks by an appropriate margin. If effectiveness is uncertain, then cost-effectiveness calculations are irrelevant,' he said.
Professor David Fitzmaurice, professor of primary care at the University of Birmingham and a GP in the city, agreed with the study conclusions and recommended GPs do not use aspirin for primary prevention .
‘The evidence for aspirin as primary prevention of CVD is flawed. I had this debate with my own PCT who basically fell back on JBS2 guidelines as evidence of effectiveness,' he said.
‘People forget that aspirin does have side-effects, with intra-cranial bleeding being the most severe but it can also trigger asthma attacks,' he said.
An accompanying editorial in the Lancet, from Professor Ale Algra, professor of clinical epidemiology at University Medical Centre Utrecht in the Netherlands, estimated aspirin was only cost-effective for use in men aged over 50 years with five times the average cardiovascular risk, or women aged 60 with five times the average risk.Aspirin: report calls for change to NICE guidance Aspirin: report calls for change to NICE guidance