Above: Professor Mark Nelson

By Stephen Easton

Recent headlines that ‘a daily dose of aspirin may do more harm than good’ have been described by one of Australia’s foremost experts on the drug as crude, sensational and likely to cause undue concern among Australians.

The authors of a recent UK study, published in the Archives of Internal Medicine, have been widely reported around the world, warning that guidelines in the US and Britain on using the drug should be revised, “after they found the risk of internal bleeding outweighed potential benefits”.

One such article, published in UK newspaper The Telegraph, reports that “experts had [previously] called for everyone over the age of 45 to consider taking a daily dose of aspirin because it can reduce the risk of a heart attack or stroke and prevent some cancers”.

While it is not clear how many ostensibly healthy middle aged and older Australians have received or follow such advice, hoping to prevent heart attacks and strokes, guidelines in this country do not recommend aspirin for everyone over a particular age.

According to Professor Mark Nelson, a senior professorial research fellow of the University of Tasmania’s Menzies Research Institute, that hasn't been suggested by Australian health practitioners since the 1980s.

“Nobody has said that at age 55, everyone should be taking aspirin or anything,” Prof Nelson said, adding that people could easily self-prescribe it because no prescription was needed.

“Everyone’s actually been saying you should do it on a risk-versus-benefit basis. It’s best to work out the absolute risk of heart attack or stroke versus the likelihood of having internal bleeding.

“I don’t think that aspirin is widely used in Australia for primary prevention. There might have been enthusiasts in the 70s and 80s, but certainly I don’t think your average GP recommends [all] people over a certain age take it for primary prevention.”

Professor Kausik Ray, the lead author of the UK study, is also quoted in the Telegraph article and elsewhere saying the benefits of aspirin for people known to have had heart attacks or strokes is “indisputable”. 

“We urge people with these conditions not to discontinue their medication unless advised to do so by their physicians for valid reasons,” Prof Ray added.

Professor Nelson has been studying the effects of the drug for a number of years through the ASPirin in Reducing Events in the Elderly (ASPREE) study, and said the UK project was a meta-analysis – a re-analysis of the combined results of previous studies – that looked mainly at middle aged people.

The aim of the ASPREE study, he said, was to weigh up the risks and benefits of taking aspirin preventively, specifically for older people, who were at higher risk of heart attacks and strokes.

“The reason we’re doing our study on the aged is that most often, the studies are done with middle aged people and then the pills are given to the elderly, so this meta-analysis supports that reason for doing [ASPREE] in the first place. This just agrees with what we already know.

“If you look at the potential benefits of aspirin, they are much greater in the elderly – the risk goes up for heart attack and stroke as you get older. Especially for strokes; the risk of stroke goes up exponentially."

Aspirin is useful in preventing the 85 per cent of strokes that involve blood clotting, according to Professor Nelson, but exacerbates the bleeding associated with the other 15 per cent of strokes, and any internal bleeding from other causes.

He added that the ASPREE study also hoped to confirm evidence that the so-called ‘wonder drug’ could help prevent or delay the onset of cognitive decline, dementia and some kinds of cancer.

“We don’t think aspirin is curative [of dementia] but it may well be that it slows the onset of the disease, and perhaps delays it for a couple of years.

“Dementia is a common thing that puts people into nursing homes so if you could keep someone home for a few years, that would be a fantastic public health outcome.

“[Professor Kausik Ray’s meta-analysis] didn’t find any effect on cancer but there is some really good evidence that it does improve survival rates – especially for bowel cancer, which is very common in the elderly.

“There’s a paucity of studies of the elderly and they need to be done because the balance of benefit versus harm is unknown. There are a lot of reasons why the elderly shouldn’t just be looked upon as middle aged individuals who are older, much like we wouldn’t assume medication used in children is the same as when used in adults.”

Professor Nelson also disagreed with a widely reported statement that the UK results were “at odds with so much existing medical opinion”, made by the Aspirin Foundation, which is funded by pharmaceutical companies including Bayer, the original manufacturer of the drug.

The ASPREE study still needs more volunteers over the age of 70 to participate, and can be reached on 1800 728 745 or by emailing aspree@med.monash.edu.au.