Aspirin for the Primary Prevention of Heart Attack and Stroke
Patients often ask me about the use of aspirin for preventing heart attacks and strokes. The US Preventive Services Task Force recently (2009) published a set of clinical guidelines regarding the use of aspirin for what is termed primary prevention of heart attacks and strokes. Primary prevention refers to trying to prevent ever having a condition by taking a medicine, checking a lab or having a procedure before you actually have the condition. So, in this case, you would be trying to avoid having your first heart attack in men or stroke in women by using aspirin. This guideline only applies to men who have never had a heart attack and women who have never had a stroke.
It is interesting that the data on prevention have consistently shown aspirin will prevent heart attacks in men and strokes in women who have never had one of these events before. The data have not shown that aspirin is effective in preventing stroke in men or heart attacks in women. Take a moment and digest what was just said.
When you take a medicine to prevent heart attack or stroke, you would like the benefit of the medication to outweigh the risks of the medicine. The tables below have yellow cells. These cells indicate combinations of risk where the benefit of aspirin is less than the risk of the aspirin. To calculate the risk of coronary heart disease in men you must use something like the Framingham Risk Score or a heart disease risk calculator such as http://healthlink.mcw.edu/article/923521437.html and to calculate the risk of stroke in women you can try out www.westernstroke.org/PersonalStrokeRisk1.xls From this information you can assess using the tables your benefit/risk of taking aspirin for primary prevention of heart attack in men and stroke in women.
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Heart Attacks prevented by use of
Aspirin in a group of 1000 Men based on the |
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Estimated Heart Attacks prevented (per 1000 men) |
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45-59 years of age |
60-69 years of age |
70-79 years of age |
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| 10-year risk of Coronary Heart Disease |
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| 1% | 3.2 | 3.2 | 3.2 |
| 2% | 6.4 | 6.4 | 6.4 |
| 3% | 9.6 | 9.6 | 9.6 |
| 4% | 12.8 | 12.8 | 12.8 |
| 5% | 16 | 16 | 16 |
| 6% | 19.2 | 19.2 | 19.2 |
| 7% | 22.4 | 22.4 | 22.4 |
| 8% | 25.6 | 25.6 | 25.6 |
| 9% | 28.8 | 28.8 | 28.8 |
| 10% | 32 | 32 | 32 |
| 11% | 35.2 | 35.2 | 35.2 |
| 12% | 38.4 | 38.4 | 38.4 |
| 13% | 41.6 | 41.6 | 41.6 |
| 14% | 44.8 | 44.8 | 44.8 |
| 15% | 48 | 48 | 48 |
| 16% | 51.2 | 51.2 | 51.2 |
| 17% | 54.4 | 54.4 | 54.4 |
| 18% | 57.6 | 57.6 | 57.6 |
| 19% | 60.8 | 60.8 | 60.8 |
| 20% | 64 | 64 | 64 |
The yellow colored boxes in the table above represent combinations of coronary heart dissease (CHD) risk and age in which the risk of harm from the aspirin is equal to or exceeds the benefit expected from the use of the aspirin. For example, if at my age, 54 years old, my calculated risk of coronary heart disease was 2%, then looking at the table with 2% risk of CHD, the use of aspirin will prevent 6.4 heart attacks per year. Since the box is yellow colored, this indicates that the risk of having an aspirin induced gastrointestinal hemorrhage, perforation or complications leading to hospitalization or death is greater than the benefit I will get from the aspirin. Or, in other words, there will be more men who have a serious complication than there will be men who have a heart attack prevented. You must decide how much risk you are willing to accept. This table has a built in assumption that risk increases as you age, you are not taking another anti-inflammatory drug, you have no upper gastrointestinal region pain, and you have never had a gastrointestinal ulcer. In the case of these additional conditions the risk of aspirin would be further increased most likely.
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Strokes prevented by the use of
Aspirin in a group of 1000 Women based on the |
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Estimated strokes prevented per 1000 women |
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10-year risk of Stroke |
55-59 years old |
60-69 years old |
70-79 years old |
| 1% | 1.7 | 1.7 | 1.7 |
| 2% | 3.4 | 3.4 | 3.4 |
| 3% | 5.1 | 5.1 | 5.1 |
| 4% | 6.8 | 6.8 | 6.8 |
| 5% | 8.5 | 8.5 | 8.5 |
| 6% | 10.2 | 10.2 | 10.2 |
| 7% | 11.9 | 11.9 | 11.9 |
| 8% | 13.6 | 13.6 | 13.6 |
| 9% | 15.3 | 15.3 | 15.3 |
| 10% | 17 | 17 | 17 |
| 11% | 18.7 | 18.7 | 18.7 |
| 12% | 20.4 | 20.4 | 20.4 |
| 13% | 22.1 | 22.1 | 22.1 |
| 14% | 23.8 | 23.8 | 23.8 |
| 15% | 25.5 | 25.5 | 25.5 |
| 16% | 27.2 | 27.2 | 27.2 |
| 17% | 28.9 | 28.9 | 28.9 |
| 18% | 30.6 | 30.6 | 30.6 |
| 19% | 32.3 | 32.3 | 32.3 |
| 20% | 34 | 34 | 34 |
The yellow colored boxes in the table above represent combinations of Stroke Risk and Age in which the risk of harm from the aspirin is equal to or exceeds the benefit expected from the use of the aspirin. For example, if at my age, 54 years old, my calculated risk of Stroke was 2%, then looking at the table with 2% risk of Stroke, the use of aspirin will prevent 3.4 strokes per year. Since the box is yellow colored, this indicates that the risk of having an aspirin induced gastrointestinal hemorrhage, perforation or complications leading to hospitalization or death is greater than the benefit I will get from the aspirin. Or, in other words, there will be more women who have a serious complication than there will be women who have a stroke prevented. You must decide how much risk you are willing to accept. This table has a built in assumption that risk increases as you age, you are not taking another anti-inflammatory drug, you have no upper gastrointestinal region pain, and you have never had a gastrointestinal ulcer. In the case of these additional conditions the risk of aspirin would be further increased most likely.
Both of these tables are liberally adapted, with slight modification, from the article: Aspirin for the Prevention of Cardiovascular Disease: U.S. Preventive Services Task Force Recommendation Statement, Annals of Internal Medicine 2009;150:396-404. This information is intended for the use of Dr. Climer and his patients.
