Will an aspirin a day help or hurt you?  

 By Richard Larew, MD, Larew Internal Medicine

For many years the expression “An apple a day keeps the doctor away” was considered folksy advice with a ring of truth to it, but no evidence to support it. In the last 20 years the notion of “an apple a day” was replaced by “an aspirin a day.” The desired outcome has changed from “keeps the doctor away” to “reduces the risk of heart attack” and this claim had ample medical evidence to support it.

What is now confusing to the public are reports that aspirin may not be providing benefit and/or has potential risks that exceed potential benefits. You may be justifiably confused as to the best path to take. Should you stop taking aspirin daily? Continue aspirin? Start aspirin?

How aspirin works

It helps to consider how a single daily aspirin impacts platelet function. Platelets form clots when blood vessels are damaged and we bleed.  Platelets can also form clots inside blood vessels when they misidentify a crack in a cholesterol plaque inside a heart blood vessel/coronary artery. This formation of a clot inside a blood vessel, which can restrict or block blood flow to the heart, is what can cause a heart attack or myocardial infarction.

Aspirin makes platelets “less sticky” and less likely to form a clot. For example, if a gentleman taking an aspirin daily nicks himself shaving in the morning, it is more difficult for a clot to form to stop the bleeding. If that same gentleman forms a crack or fissure in a cholesterol plaque in his left main coronary artery, he is less likely to form a clot and hence less likely to have a heart attack.

Aspirin therapy can reduce the risk of a second heart attack… 

What many studies over many years have shown is that for a person who has experienced a first heart attack, taking an aspirin per day after that first event reduces the risk of a second heart attack.  These many studies, over many years, with many thousands of patients clearly demonstrated the benefit of aspirin in helping to prevent a second heart attack. There is no debate here: a daily aspirin reduces the risk of a second heart attack. 

However, please note: aspirin has proven efficacy in helping to reduce the risk of a second heart attack, but it does not completely eliminate the risk. While the likelihood that platelets will form a clot at a cholesterol plaque is decreased, aspirin does not make the plaque disappear, so the possibility of a heart attack cannot be eliminated.

…but can a daily aspirin reduce the risk of getting a heart attack in the first place?

It seems reasonable to assume that if a daily aspirin can reduce the risk of a second heart attack, it should also reduce the risk of a first heart attack. The problem is that we do not know who is actually going to experience a first heart attack. We have no proverbial crystal ball to help us here. We know the risk factors for coronary artery disease: hypertension, diabetes, hyperlipidemia, family history and smoking (see “Know Your Cardiac Risk Factors” sidebar below for additional details). A person who has one or more of these risk factors is at greater risk for a heart attack than someone who has no risk factors. For years I have treated people who have one or more risk factors with a daily aspirin; for those with no risk factors, no daily aspirin was recommended.

So why the current controversy over a daily aspirin?

The current debate around aspirin therapy started with the recommendations of some physicians, and the decisions of some patients, to start taking daily aspirin even in the absence of any known cardiac risk factors. In this group of people there is no direct or indirect evidence of benefit from daily aspirin use. However, they may be at a small risk of potential complications including a propensity for easier bleeding should they develop a stomach ulcer, experience major trauma such as striking their head in a fall or experience internal bleeding as a result of being involved in a motor vehicle accident.

My recommendations

• If you have already had a heart attack, coronary bypass surgery or a coronary artery stent, a daily aspirin should be taken to reduce the risk of a second heart attack. The evidence remains clear and compelling for patients in this group.
• If you have one or more risk factors for coronary artery disease, a daily aspirin to help prevent a first heart attack is a sound strategy.
• If you have no identified risk factors for coronary artery disease, a daily aspirin is not needed and need not be taken.
• If you have no identified cardiac risk factors but are worried about having a possible heart attack, you can certainly take an aspirin daily to try and minimize your risk of a first heart attack. No prescription is required. But please review this decision with your doctor in order to fully understand the potential risks in light of your own health history. For example, if you have a history of bleeding peptic ulcer disease, you probably should not be taking an aspirin daily.  Similarly, if you have a propensity for falling, the risks of potential complications from aspirin-induced bleeding may exceed potential benefits of a daily aspirin.

Know Your Cardiac Risk Factors

Nonmodifiable risk factors (those that cannot be changed) include:

• Male gender. Men have a greater risk of heart attack than women do, and men have heart attacks earlier in life than women.
• Advanced age. Coronary artery disease is more likely to occur as you get older, especially after age 65.
• Family history of heart disease, especially if you have a parent diagnosed with heart disease before age 50.
• Race. African Americans have more severe high blood pressure than Caucasians and, therefore, have a higher risk of heart disease. The risk of heart disease is also higher among Mexican Americans, American Indians, native Hawaiians and some Asian Americans.

Modifiable risk factors (those you can treat or control) include:

• Cigarette smoking and exposure to tobacco smoke.
• High blood cholesterol and high triglycerides – especially high levels of LDL (“bad”) cholesterol and low levels of HDL (“good”) cholesterol. Your doctor can provide specific guidelines for you.
• High blood pressure increases the heart’s workload, causing the heart muscle to thicken and function abnormally.
• Diabetes. Better control reduces risk.
• Physical inactivity. Key to helping control blood cholesterol, diabetes, obesity and blood pressure is regular, moderate to vigorous physical activity.
• Obesity. Note that a sustained weight loss of 3 to 5% of your body weight may lead to significant reductions in some cardiac risk factors. Greater sustained weight losses (eg. 10 % of your weight) can drop your blood pressure as well as your cholesterol and blood glucose levels.
• Stress. This can be more difficult to assess because of the subjective nature of the problem.
• Diet and nutrition. A heart-healthy diet emphasizes vegetables, fruits, whole grains, low-fat dairy products, poultry, fish, legumes, nuts and non-tropical vegetable oils and limits sweets, sugar-sweetened beverages and red meats.
• Alcohol. Too much can raise blood pressure, contribute to high triglycerides and obesity. If you drink, limit consumption to no more than two drinks per day for men and no more than one drink per day for women.

Source: American Heart Association