Due to a technical glitch, I’m republishing this post from two days ago.
Aspirin is a unique drug, the prototypical two-edged sword of pharmaceuticals. It has the capability of stopping platelets, the sticky elements in our blood, from forming clots that cause strokes and heart attacks when arterial plaques rupture, but it increases the risk of serious bleeding into the brain or from the GI tract. Despite these powerful properties, aspirin is available over the counter and is very cheap, thus anyone can take it in any dosage they want.
In 2014 the skeptical cardiologist wrote a post entitled “Should I take aspirin to prevent stroke or heart attack?”, it pointed out that although Dr. Oz had recently told almost all middle-aged women to take a baby aspirin and fish oil, there was, in fact no evidence to support that practice.
In 2018 I revisited (Revisiting Who Should Take Aspirin) my aspirin recommendation after the publication of the ASPREE (Aspirin in Reducing Events in the Elderly) trial results were published in the New England Journal of Medicine and concluded:
The ASPREE study confirms what I advised in 2014 and hopefully will further reduce the inappropriate consumption of aspirin among low risk individuals.
I’ve taken more patients off aspirin since 2014 than I’ve started on aspirin and what I wrote then remains relevant and reflects my current practice. Especially in light of the increase cancer risk noted in ASPREE, patients should only take aspirin for good reasons.
Yesterday, I received an email from the USPSTF which indicates their recommendations for aspirin in primary prevention will be substantially modified in light of ASPREE and other data which have emerged in the last 3 years. These are draft comments and the USPSTF is inviting public review and comment:
The big change was in individuals 60 years and over without clinical evidence of cardiovascular disease (primary prevention) with a recommendation against initiating aspirin therapy in this group:
These recommendations have generated extensive media coverage including a featured NY Times article this morning. It’s good to see the USPSTF revising ASA recommendations and hopefully this will further reduce the inappropriate use of aspirin in low-risk individuals. I wonder if Dr. Oz will recant his spurious advice now.
Optimal Aspirin Usage in Primary Prevention
In my practice, the answer to the question of who should or should not take aspirin is based on whether my patient has or does not have significant atherosclerosis.
If they have had a clinical event due to atherosclerotic cardiovascular disease (stroke, heart attack, coronary stent, coronary bypass surgery, documented blocked arteries to the legs) I recommend they take one 81 milligram (baby) uncoated aspirin daily.
If my patient has not had a clinical cardiovascular event but we have documented advanced subclinical atherosclerosis by imaging such as :
- vascular screening (significant carotid plaque)
- Abnormally high coronary calcium score
- Incidentally discovered significant plaque in the aorta or peripheral arteries (found by CT or ultrasound done for other reasons)
then I recommend a daily baby aspirin (assuming no high risk of bleeding).
I have been using a coronary calcium score >100 as a guide for who benefits from aspirin since a study entitled “The Use of Coronary Artery Calcium Testing to Guide Aspirin Utilization for Primary Prevention: Estimates from the Multi-Ethnic Study of Atherosclerosis” was published in 2015.
This study found
Individuals with CAC ≥ 100 had an estimated net benefit with aspirin regardless of their traditional risk status (estimated NNT5 of 173 for individuals <10% FRS and 92 for individuals ≥ 10% FRS, estimated NNH5 of 442 for a major bleed). Conversely, individuals with zero CAC had unfavorable estimations (estimated NNT5 of 2,036 for individuals <10% FRS and 808 for individuals ≥ 10% FRS, estimated NNH5 of 442 for a major bleed)
Randomized trials testing this approach are needed but in the next few years several large aspirin trials will be completed and hopefully, we will get a more refined understanding of who benefits most from aspirin for primary prevention.
Until then remember that aspirin is a powerful drug with the potential for good and bad effects on your body. Only take it if you and your health care provider have decided the benefits outweigh the risks after careful consideration of your particular situation.
N.B. Some other skepcard posts relevant to aspirin
N.B. 2 The inclusion criteria for ASPREE define significant cardiovascular disease as follows a past history of cardiovascular or cerebrovascular event or established CVD, defined as myocardial infarction (MI), heart failure, angina pectoris, stroke, transient ischemic attack, >50% carotid stenosis or previous carotid endarterectomy or stenting, coronary artery angioplasty or stenting, coronary artery bypass grafting, abdominal aortic aneurysm