Primary prevention aspirin phase out begins
By Mark Pownall
The phasing out of aspirin as a primary prevention agent in vascular disease has begun with a move by the Scottish Intercollegiate Guidelines Network (SIGN).
Draft guidance by the body concludes the recent stream of evidence has ‘increased the uncertainty about the role of aspirin in primary prevention' and that it is ‘not recommended' for primary prevention in patients with diabetes.
If accepted, the guidance will pile more pressure on NICE to change guidance made in May 2008 which recommended all diabetes patients over 50 should receive low-dose aspirin, and that those under 50 at higher risk should be on low-dose aspirin.
Pulse reported earlier this month that data from the Aspirin for Asymptomatic Atherosclerosis trial suggested prescribing aspirin to patients identified as at high vascular risk through screening could not be justified when weighed against the risk of bleeding.
The research, presented at the European Society of Cardiology's annual congress in Barcelona, came on top of a previous meta-analysis published in The Lancet in May also questioning use of aspirin for primary prevention.
Professor David Fitzmaurice, professor of primary care at the University of Birmingham and a GP in the city, predicted SIGN had pointed the way towards a wider re-think.
‘The use of aspirin in primary prevention has always been an article of faith rather than evidence based and the evidence is now accumulating that it is not the universal panacea that we thought,' he said.
‘The thinking was that, as people with diabetes had a raised cardiovascular risk equivalent to having had an acute MI, low-dose aspirin was justified, but the evidence is that it is more complicated than that. It's time we started re-evaluating the received wisdom around the use of aspirin.'
Professor Colin Baigent, professor of epidemiology at the clinical trial service unit at the University of Oxford, said: ‘The benefit of aspirin in people with diabetes who have not had a cardiovascular event is still a research question that trials such as ASCEND are looking into.'
‘At the moment, in terms of a general recommendation, there's no good evidence of net benefit, and it remains a matter of individual decisions between doctors and their patients.'
NICE said it was due to review its guidance on over-50s with significant risk factors in May 2011 but a spokesperson added it ‘will continue to monitor ongoing research' and ‘has the processes in place to carry out a rapid review if required.'
Its guidance over adults in the highest and moderately high risk groups is to be reviewed early next year and the spokesperson said it would take the new evidence into account.
The Joint British Societies has already pledged to look again at their guidance recommending aspirin for primary prevention in high-risk and diabetic patients.The days of using aspirin as a primary prevention agent in vascular disease appear to be numbered The days of using aspirin as a primary prevention agent in vascular disease appear to be numbered Contention about prevention
What SIGN's new draft says
‘Low-dose aspirin is not recommended for primary prevention of vascular disease in patients with diabetes'
What NICE says
‘Offer low-dose aspirin to anyone with diabetes over 50, if blood pressure is below 145/90 mmHg. Offer low-dose aspirin to anyone with diabetes under 50 years old who has significant other risk factors'
Clinical Guideline 66, May 2008
What the JBS-2 guidelines say
Low dose aspirin is recommended for selected people with diabetes (> 50 years, or who are younger but have had the disease for more than 10 years, or who are already receiving treatment for hypertension), once blood pressure has been controlled
(Source: Heart 2005;91(Suppl V):v1–v52.