For many years low-dose aspirin was considered to be a way to provide at least a
small degree of protection against heart attacks and ischemic strokes because aspirin
decreases the propensity of blood to clot. And one-quarter of people age 40 or
older (about 29 million Americans) are taking a daily aspirin. But low-dose aspirin
(81 mg) increases the risk of cerebral hemorrhage and gastrointestinal bleeding,
and it has become uncertain if there is a net benefit from aspirin therapy for people
at average or even moderately elevated CVD risk.
The U.S. Preventive Services Task Force (USPSTF) advises aspirin therapy for
primary prevention of CVD for people in their fifties who are at high risk of CVD
(10% or higher risk of a heart attack or stroke over the next 10 years, based on the
calculator, tinyurl.com/riskCVD) and who are not at increased risk for bleeding.
The Task Force also said that aspirin can be considered for people in their sixties
who are at high risk of CVD, but cautions that their risk of bleeding is greater and
aspirin’s net benefit smaller. Because of inadequate evidence, the USPSTF made
no recommendation for people under age 50 or over 70.
A 2016 meta-analysis from 11 trials of aspirin for primary CVD prevention, found
that aspirin reduced the relative risk of nonfatal myocardial infarction by 22% and
death by 6%, but was associated with a 59% increase in gastrointestinal bleeding
and a 33% increase in hemorrhagic stroke.
A 2019 meta-analysis considered a total of 13 trials with 164,225 participants without
CVD. Aspirin use was associated with significant reductions in cardiovascular
events (60.2 vs. 65.2 per 10,000 participant-years) but an increased risk of major
bleeding events (23.1 vs. 16.4 per 10,000 participant-years).
Three recent clinical trials suggest that taking aspirin for primary prevention of
CVD is not beneficial or, at best, marginally beneficial. In the first trial, ARRIVE
(Aspirin to Reduce Risk of Initial Vascular Events), no prevention of CVDs was
found over the five year study period. Both patients on daily low-dose aspirin and
those taking a placebo had similarly low rates of CVD (about 4%). Rates of gastrointestinal
bleeding (mostly mild) were also low, at 0.5% in the group on placebos,
but higher in the aspirin group at 1%.
A second study, ASCEND (A Study of Cardiovascular Events in Diabetes), measured
CVD in diabetics, a group at elevated risk. After seven years, the study found
that the group taking aspirin had a slightly lower rate of CVD events, 8.5%, compared
to 9.6% in the placebo group, but this was counterbalanced by a higher rate of
major bleeding events (4.1% vs. 3.2%).
The third, a five year ASPREE (ASPirin in Reducing Events in the Elderly) study,
found that low dose aspirin conferred no significant improvement in rates of CVD
events, disability, or dementia. The aspirin group had a higher rate of major bleeding,
including hemorrhagic strokes (3.8% vs. 2.7% in the control group).
The study authors concluded that the use of low-dose aspirin as a primary prevention
strategy in older adults resulted in a significantly higher risk of major hemorrhage
and did not result in a significantly lower risk of cardiovascular disease than
According to a review in the University of California, Berkeley Wellness Letter,
“…in more recent years, many experts stopped recommending aspirin therapy to
prevent first heart attacks and strokes (primary prevention) in most people, though
they continue to strongly advise it to prevent recurrences (secondary prevention) in
people who already have CVD.” In 2019, the American Heart Association and the
American College of Cardiology recommended against the use of low-dose aspirin
in people older than 70 who do not have existing CVD or in anyone who has an
increased risk of bleeding.
Taken together, these studies suggest that if you are at low are moderate risk of
CVD taking low dose aspirin would provide little benefit and, like all medications,
it should only be taken if prescribed by a health professional. An editorial in the
New England Journal of Medicine that commented on the three aspirin trials concluded
that “… the best strategy for the use of aspirin in the primary prevention of
cardiovascular disease may simply be to prescribe a statin instead.”
In the presence of increased risk of stroke because of atrial fibrillation, and when
other CVD risk factors are present, including age over 75, previous stroke, heart
valve, and other cardiac disorders, anti-clotting drugs may be prescribed. In addition
to aspirin, there are other antiplatelet or anticoagulant drugs to reduce the
likelihood of heart attack or stroke by inhibiting blood clot formation. These drugs
include warfarin (Coumadin, Jantoven), clopidogrel (Plavix) and prasugrel (Effient)
and a group of newer anticoagulants that are easier to monitor (Eliquis, Pradaxa,
Savaysa, Xarelto). They are only taken when prescribed and supervised by a
This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel