Aspirin is the most commonly used medicine in the world. In most cases, aspirin is taken as a pain killer. However, not many are aware that aspirin has another beneficial function, particularly taking the daily low dose aspirin. Aspirin lowers the risk of blood clot formation inside the coronary artery (blood vessel supplying blood and nutrients to the heart) due to its antiplatelet activity.
The same is true of the blood vessels to the brain. The platelets are tiny particles in the blood which help the blood to clot when a vessel is damaged. Research shows that the activation of platelets is associated with heart attack and stroke. Therefore, the antiplatelet agents in aspirin may be used to prevent cardiovascular disease in patients who do not have a history of cardiovascular disease. This is called primary prevention.
For decades, low dose Aspirin has been recommended for the primary prevention of cardiovascular disease. Nowadays, an increasing number of Americans take aspirin to combat heart attack or stroke. It is estimated that nearly 50 million people in the United States take low dose aspirin (75-80 mg) on a daily base for this purpose. However, recent disputes have drawn great public attention about the efficacy and safety of low dose aspirin in the primary prevention of cardiovascular disease (CVD).
The beneficial effects of aspirin in the primary prevention of cardiovascular disease appears overvalued
In 2005, Harvard conducted a study to investigate whether or not low-dose aspirin offered cardiovascular benefits for women. In this clinical trial, nearly 40,000 healthy women were enrolled and studied for 10 years straight. The results did not show any heart benefit from aspirin therapy, therefore the authors concluded aspirin did NOT lower the risk of heart attack or death from cardiovascular causes among women.
In 2009, a meta-analysis published in the journal, “The Lancet”, evaluated the efficacy of aspirin for primary prevention of cardiovascular disease, concluding that for patients without a history of cardiovascular disease, “aspirin is of uncertain net value”.
Another study investigating the beneficial effects of aspirin in diabetic patients also indicated that aspirin seems to have NO benefit in the primary prevention of cardiovascular disease in diabetes.
Based on a series meta-analysis involving more than 100,000 patients at high risk for cardiac events, Dr. Cleland pointed out that there is NO evidence aspirin is effective for the primary prevention of cardiovascular disease.
A systematic review published in Am J of Cardiovascular Drug 2015 concluded that aspirin appears to provide, at most, modest benefits in primary prevention of cardiovascular disease.
A most recent report in 2016 also demonstrated that although multiple, large, and well-performed clinical studies have been conducted, the benefit of aspirin for the primary prevention in patients with high cardiovascular risks is still unclear.
In addition, aspirin increases risk of bleeding (commonly gastrointestinal bleeding), even in low dose, especially in those elderly patients over 60 years.
Based on the clinical research above, we can summarize as following:
- Evidence of benefits are lacking for primary prevention and, if benefits do exist, may not outweigh harm.
- Even though in some clinical studies, long term use of aspirin in men show relative risk reduction for myocardial infarction (MI), no benefit was noted in regard to strokes or other causes of mortality.
- In women, long term use of aspirin show relative risk reduction for strokes, but no benefit was noted concerning myocardial infarction or other causes of mortality.
- It is uncertain whether there is benefit of aspirin in the primary prevention of CVD in people with diabetes.
- Aspirin increases risk of bleeding (intracranial or gastrointestinal bleeding) even in low dosage.
Who should take aspirin to prevent cardiovascular disease?
The U.S. Preventive Services Task Force (USPSTF) recommends the use of aspirin for the primary prevention of cardiovascular disease (CVD) when a net benefit is present. A net benefit means that the potential benefit from taking aspirin outweighs the harms, mainly gastrointestinal (GI) bleeding:
- Aspirin is recommended for men ages 45-79 to reduce risk of myocardial infarction (MI) when a net benefit is present.
- Aspirin is recommended for women ages 55-79 to reduce risk of ischemic stroke when a net benefit is present.
- The USPSTF recommends against the use of aspirin for the primary prevention of MI in men younger than age 45, or prevention of stroke in women younger than age 55.
- Also, the USPSTF found the evidence insufficient to recommend for or against the use of aspirin for MI or stroke reduction in men and women age 80 and older.
Keep in mind, if you are considering taking aspirin to protect against heart attacks or stroke, ask your healthcare provider these two questions:
- Given my age, risk factors, and overall health, are there any risks of me developing cardiovascular disease like heart attack or stroke?
- Is there a chance that I might have an increased risk of bleeding if I take aspirin?
It’s important to know the answers to these questions, because your health care provider needs to weigh the harms and benefits, should you take aspirin. If you have a high risk of developing cardiovascular disease and your healthcare provider is in favor of you taking daily aspirin, then take it. Likewise, if you are at high risk of bleeding and it outweighs the benefits, do not take it. It’s crucial that you don’t self-diagnose and self-prescribe aspirin on your own. Ask your doctor first, because aspirin is not always as safe as you might think it is.
Interestingly, a recent randomized clinical trial conducted in China showed that Qi-Shen-Yi-Qi Dripping Pills (a Chinese compound herbal medicine with Astragalus, Tienchi Ginseng and Dan Shen ) have similar beneficial effects for the secondary prevention of Myocardial Infarction and have lower adverse effects, especially GI bleeding. This provides an alternative for the prevention of cardiovascular disease in patients with high risks of cardiovascular disease.