September 17, 2018

expert reaction to three studies looking at aspirin use in healthy old people and bleeding, disability-free survival, cardiovascular events and death

Researchers, publishing in the New England Journal of Medicine, report that there was high mortality rates among healthy older adults who received daily aspirin than among those how received a placebo.

Prof Stephen Evans, Professor of Pharmacoepidemiology, London School of Hygiene and Tropical Medicine, said:

“These three papers describe multiple analyses of a large and well-conducted study examining the effects of aspirin in older healthy people.  As the authors state, the evidence is that aspirin is beneficial in reducing heart attacks in those who have had a previous heart attack or evidence of heart disease, but the evidence for prevention in otherwise healthy people is not clear.

“This study ensured that a truly valid comparison was made between those given aspirin and those given a dummy pill (placebo).  It was conducted in healthy older people whose rates of cancer and death were much less than those of people of that age generally.  Those with illnesses were excluded.

“It showed an expected increase in bleeding in those given aspirin.  The small benefit on heart disease was outweighed by overall increases in other diseases and suggests that in healthy older people, without heart disease, there is no benefit to low-dose aspirin (though the dose here – 100mg – was a little higher than that often used for prevention, 75mg).

“The surprising findings here were the small increase in overall mortality, mainly through cancer including bowel cancer.  Previous studies have not shown such increases and reductions in bowel cancer have been seen in some studies.  The authors, rightly, suggest treating the unexpected effects with caution but they also show that benefits of aspirin in healthy people are at best limited, and may well be harmful, and this harm may be increased beyond age 73.”

Dr June Raine, Director of MHRA’s Vigilance and Risk Management of Medicines Division, said:

“The safety of all medicines is of paramount importance and under constant review.  Our priority is to ensure that the benefits of a medicine outweigh the risks.  Any new significant information which may impact on the balance of benefits and risks will be carefully reviewed and independent scientific advice on the need for regulatory action will be sought if required.”

Prof Peter Rothwell, Director of the Centre for Prevention of Stroke and Dementia, and Action Research Chair of Neurology in the Nuffield Department of Clinical Neurosciences, University of Oxford, said:

Are there any important limitations of the study, in your opinion?

“Firstly, the results only apply to primary prevention.  Aspirin is still recommended at age over 70 years in secondary prevention (i.e. after a stroke or heart attack), although the risk of bleeding is increased at older ages in secondary prevention as well.  Secondly, the study didn’t look at the question of whether people aged over 70 years should stop aspirin if they have been taking it for several years already (i.e. it wasn’t a withdrawal study), although it provides good evidence about the risks and benefits of starting aspirin anew in that age group.  Thirdly, the trial was stopped slightly earlier than planned and the investigators are intending to continue follow-up in order to see whether any other risks or benefits emerge over the longer term.

Do the results provide the definitive evidence that was previously lacking on use of aspirin in primary prevention?

“The results provide the most reliable evidence on the balance of risk and benefit of starting aspirin after the age of 70 years in healthy individuals.  There were too few individuals in the over-70 age group in previous trials to draw reliable conclusions prior to ASPREE.

What is the take-home message for the use of daily low-dose aspirin in the primary prevention of CVD in healthy older adults from the trial?

“There is no overall benefit in terms of mortality, disability or dementia of starting aspirin and taking it for a period of about five years in healthy individuals aged over 70 years.”

Declared interests

age
Prof Stephen Evans: “No conflicts of interest.”

Dr June Raine: “No conflict of interest.”

Prof Peter Rothwell: “I have received payments from Bayer for being on the Steering Committee of the ARRIVE trial – another trial of aspirin in prevention of vascular events.”