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Monday’s medical myth: take an aspirin a day after you turn 50

Aspirin is a historical marvel. It’s been manufactured for more than a century and is still in widespread use. No other medication can claim as many different narratives and uses as this analgesic – it’s…

This blanket advice doesn’t hold. Dark Dwarf

Aspirin is a historical marvel. It’s been manufactured for more than a century and is still in widespread use. No other medication can claim as many different narratives and uses as this analgesic – it’s been known as:

  • A traditional medicine – aspirin-like treatments, based on salicylate, have been derived from plants such as willows for millennia

  • An international blockbuster – at the turn of the twentieth century, aspirin was one of the few effective treatments for fever and pain, and was wildly popular (and profitable)

  • A hazard to children – aspirin was recognised in the 1980s as a potential cause of childhood death

  • A modern wonder-drug – aspirin has been resurrected as an important and inexpensive medication for the prevention and treatment of heart attacks and strokes.

And there are many fascinating tales of intrigue, international politics and corporate espionage in aspirin’s history.

German affiliates undermined the manufacture of explosives in the United States during World War I by cornering the market of a key ingredient, under the guise of aspirin production. And Germany was forced to hand over the trademark “Aspirin” as part of war reparations in the Treaty of Versailles.

In the modern context, it is commonly believed that once individuals reach a certain age, it’s wise to take “an aspirin a day” for good health.

This narrative starts in 1948 with Dr Lawrence Craven, a general practitioner, in California. He had observed that aspirin was a mild blood thinner and reasoned that it might be able to prevent heart attacks.

Dr Craven enrolled his male patients, aged 40 to 65, into a clinical trial and asked them to take aspirin daily. In the 1950s, he published three articles on his trial and concluded that aspirin appeared to protect his patients from heart attacks and strokes.

Aspirin is an inexpensive way to prevent heart attacks and strokes. But that doesn’t mean everyone over 50 should take them each day. Mark van Laere

Dr Craven died in 1957 (of a heart attack!) and his results – which were published in the obscure Mississippi Valley Medical Journal – were promptly forgotten.

How aspirin works in clotting and bleeding was discovered in the 1960s. And by the 70s and 80s, aspirin was tested in clinical trials for heart attacks and strokes. These studies demonstrated that aspirin was effective in preventing further heart attacks or strokes (known as secondary prevention).

In the 1990s, our “medical myth” was not considered a myth. The American College of Chest Physicians (ACCP), a respected group that publishes guidelines on the use of blood thinners, recommended that aspirin “be considered for all individuals over age 50 years who are free of contraindications”.

But others were less confident about such a broad recommendation. Firstly, although aspirin is unambiguously beneficial for those who already had cardiovascular disease, the evidence was less clear for those who did not (such use is known as primary prevention).

Secondly, long-term aspirin therapy has potential harms – it increases the risk of bleeding, which, in some cases, can be life-threatening. Conceptually, if an individual’s risk of cardiovascular disease is low, then the potential benefit of aspirin would not outweigh the potential harms from bleeding.

The most recent recommendations from the ACCP (published February 2012) are a “soft” suggestion for aspirin for primary prevention in those aged 50 years and above. It recognises that the benefits to heart attacks and strokes are closely matched with the risk of major bleeding.

The authors were swayed by some recent data suggesting aspirin might lower cancer risk and death. Nevertheless, they emphasised the need for shared decision making between doctors and patients.

So, is that the end of this particular aspirin narrative?

Not quite. In keeping with the drama of the history of aspirin, a major study examining the role of aspirin in primary prevention was published in the same month as the ACCP guidelines. It confirmed that the benefits of lowering heart attacks and strokes were similar to the increased risks of bleeding.

Importantly, the study found no reduced risk of cancer, which is contrary to previous reports.

Behind this lack of clarity is the uncertainty of small numbers – trying to balance a small gain with a small risk. For someone who has never had a heart attack or stroke, the likelihood of benefit from aspirin is low, but the payoff could be massive. Similarly, the odds of being harmed by aspirin are also low, but could be catastrophic if it occurred.

Those aged over 50 years without a history of cardiovascular disease may benefit from regular low-dose aspirin. But that depends on their individual risk (and perceptions of risk) of heart attack, stroke and major bleeding.

So before you pick up the aspirin for your daily dose, talk to your GP about the potential risks and benefits for you.

Join the conversation

10 Comments sorted by

  1. Antonio Manuel Santos Cristovao

    logged in via Facebook

    Reading this I remember the doctors in my town recomend to new mothers to substitut their milk by powder milk "much more safe and complete".I only understood why when I saw the same proceding in Africa!!

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  2. Jim Wright

    Retired Civil/Structural Engineer, IT Consultant/Contractor

    Like all medication recommendations, the ones discussed here must be applied with a little bit of common sense. In 1987, in my mid-forties, I needed to have a quintuple heart bypass, after which it was established that my natural cholesterol level was about 8. Since then I have been taking statins and aspirin daily and my cholesterol level has never exceeded 5.2. I have had a number of small surgical procedures since, where I dropped the aspirin for a few days before and a few days after, without any dramas. Yes, aspirin is associated with more bleeding than would otherwise be the case, but in all my minor experiences, this had no more than nuisance value. The important thing is to ensure that all of your medical consultants are aware of your history and can offer appropriate advice.

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  3. David Healy

    Retired

    The dosage is important. Even if you have a family history of stroke or cardoivascular disease, a low-dose aspirin (80 - 100 mg) will probably provide sufficient risk reduction. I've been told enteric-coated aspirin is the way to go to avoid stomach upset. I've used both coated and uncoated, and can't tell the difference.

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  4. Margo Saunders

    Public Health Policy Researcher

    The medical literature has highlighted concerns about the potential for a 'rebound effect' when stopping long-term aspirin use. When undergoing a surgical procedure a few years ago, my surgeon was absolutely insistent that I discontinue taking daily low-dose aspirin prior to surgery, even though the literature has reported minimal risk of post-surgical complications, especially compared to the cardiovascular risks of stopping aspirin. The likelihood of having to stop aspirin in such situations may be a consideration for some people in deciding whether to take aspirin on a daily basis, especially if they are using it for primary prevention.

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  5. Colin MacGillivray

    Architect, retired, Sarawak

    Good article which ends with "talk to your GP about the potential risks and benefits for you."
    I don't want to denigate GPs but is it reasonable to expect them to have up to date and deep knowledge of this discussion?
    Is there a danger that they will be biassed by recent experiences or the last article they read?
    Isn't the internet a better source of information to enable an informed decision to be made?

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    1. Michael Tam

      General Practitioner, and Conjoint Senior Lecturer at UNSW Australia

      In reply to Colin MacGillivray

      "Is it reasonable to expect" - yes. In Australia, general practitioners are the main primary care practitioners. A general practitioner may not have the knowledge instantly on hand, but should be able to find and contextualise the relevant information (e.g., they may call a cardiologist colleague).

      And no, the internet is not a "better source of information" for the majority of individuals. The internet is basically "all sources" of information, both good and bad, pertinent and irrelevant…

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  6. Colin MacGillivray

    Architect, retired, Sarawak

    Michael
    Points taken.
    Would it be possible to set up a website to assist GPs addressing this issue by providing a list of questions to be answered by the patient? The website might have boxes to tick or enter numbers into. The GP could input all the information gained from the patient during the consultation. The website would then provide the recommendation and dosage, period for the next review and period to watch out for problems to arise. And the latter two would flash on his nurse's computer when time period passed. The GP could choose to pass on the information or not. The database of answers and the recommendation would stay on the patient's records at the practice.
    Colin

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    1. Michael Tam

      General Practitioner, and Conjoint Senior Lecturer at UNSW Australia

      In reply to Colin MacGillivray

      Dear Colin,

      Those are great IT ideas and I'm sure our medical records system will eventually move down that pathway. In Australia, there are a number of "point-of-care" tools that work alongside the computerised record. For example, the RACGP promotes the "PrimaryCare Sidebar" tool: http://www.racgp.org.au/ehealth/primarycaresidebar

      This tool runs in real-time and can extract information from the current patient's open file. It can recognise diagnoses (e.g., diabetes) and evaluate whether aspects of management potentially need to be addressed (e.g., whether blood pressure is on target, or the last time sugar control was reviewed by a blood test, etc.)

      There are still many pragmatic issues with the use of such tools - some technical, and some related to how doctors use computers - but this is definitely a potential mechanism for improving quality of care.

      Yours sincerely,
      Michael

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  7. Stiofán Mac Suibhne

    Contrarian / Epistemologist

    I think if you review the research on reduction of death from all causes for people taking long term low dose aspirin and the nature of the adverse consequences (which seem to be overwhelomingly trivial) one might conclude low dose aspirin is a sensible option for people over 50.

    It's probably worth considering the 'myth' of medical paternalism and how the 'myth' of big pharma marketing drives prescribing habits. The usual product champions dont line up for out of patent drugs. It's not straight forward, I am not certain GPs are the objective source of advice mooted in the article. Like the rest of us they are subject to the jibber-jabber of the latest research that is paraded as evidence and have their own context.

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