Cardiovascular disease and coronary heart disease are the leading causes of death in men and women in the US. Men tend to have higher risk for coronary heart disease compared to women, but women have a higher risk of stroke compared to men. It’s becoming increasingly common for people to use low-dose aspirin as a way to minimize the risk of cardiovascular disease and diabetes. It’s estimated that aspirin therapy is helping to prevent more than 200,000 deaths every year in the US. But aspirin therapy is not without its risk, with elderly populations particularly vulnerable to some of aspirin’s more hazardous side effects.
Risks of aspirin therapy
- Intracranial hemorrhage risk is increased by 40% when combined with aspirin therapy. Although that sounds high, the absolute risk is still low. As a point of comparison, the drug warfarin is associated with approximately 4000 intracranial hemorrhages a year, while aspirin therapy is associated with about 3000 per year.
- Upper gastrointestinal (GI) bleeding risk is associated with aspirin therapy, and the risk increases with age. The frequency is approximately 1 per 1000 patients per year in all age groups, and it increases to 4 per 1000 for those above 75 years old.
To put these risks in perspective, take for example a healthy 50 year old man who has a life expectancy of approximately another 28 years. If he starts low-dose aspirin therapy at the age of 50, he will have a lifetime 5% risk for upper GI bleeding, a 1.3% risk for major upper GI bleeding, a 0.5% risk for intracranial hemorrhage, and a 0.2% risk for death. The total increased risk is about 7%, meaning that 1 out of every 15 patients would have some type of negative and impactful health consequence from aspirin therapy.
Aspirin therapy effectiveness for women.
Aspirin therapy effectiveness largely depends upon the age of the woman undergoing supplementation.
- Studies don’t seem to support any cardiovascular benefit for women to take low-dose aspirin at younger ages. There is some evidence in reduction of stroke risk, but that is offset by a heightened risk for major bleeding. For every 1000 women taking an aspirin regimen tracked over an approximately 5 year period, there would be 2 fewer strokes but at least 2 more hemorrhages when compared to a control group. These numbers are similar to the statistics for men at this age group.
- Studies suggest that there is less overall benefit for older women to take low-dose aspirin between the ages of 50 to 65.
- Among elderly women 65 years of age and older, there is evidence for decreased risk of cardiovascular disease, but not for stroke.
It should also be noted that in women smokers, aspirin therapy did not reduce the risk for stroke and increased the risk for cardiovascular disease when combined with smoking. For further reading, please see Murphy SA: Women’s Health Study: low dose aspirin in primary prevention. Journal of the American College of Cardiology 46:CS7, 2005.
Is aspirin safe for the elderly?
Aspirin for primary prevention in older adults: Studies suggest that for every 1000 men aged between 70 and 74 years old, low-dose aspirin would prevent about 40 myocardial infarctions and about 20 deaths. But these numbers should be weighed against the fact that aspirin therapy would cause approximately 60 major upper GI hemorrhages or intracranial hemorrhages, resulting in approximately 15 deaths. Since the risk / reward ratio is not clear-cut, older adults should discuss aspirin therapy with their doctors. For further insight, please see Algra A, Greving JP: Aspirin in primary prevention: sex and baseline risk matter. LancetÊ373:1821, 2009.
Precautions / contraindications for taking aspirin with other drugs.
- Avoid combining aspirin with the anti-coagulant warfarin.
- Avoid combining aspirin with nonsteroidal anti-inflammatory drugs, since the risk for major bleeding increases over 100 percent.