Many people have the impression that all middle-aged individuals should be on low-dose aspirin. Not true.
The United States Preventive Services Task Force policy for the preventive use of aspirin (usually “baby aspirin”, 81 milligrams) is relevant to only “primary prevention” of cardiovascular disease, not “secondary prevention” (preventing a second cardiovascular event). The secondary preventive benefits of aspirin are strongly established. Although the task force recommendations are felt to be the gold standards for prevention, its policies for aspirin are rapidly becoming out of date.
The primary preventive use of aspirin has been based on cardiovascular risk factors balanced with the risk of hemorrhage, which can be heightened with aspirin.
Specific risk factors for cardiovascular disease include hypertension, diabetes, smoking and high cholesterol. Risk factors for hemorrhage include a history of ulcers, bleeding disorders, renal failure and liver disease.
The current task force recommendations, written in 2016, are:
• Initiate low-dose aspirin use for the primary prevention of cardiovascular disease in adults aged 50 to 59 who have a 10% or greater 10-year cardiovascular disease risk (calculated by evaluating risk factors), are not at increased risk for bleeding, and have a life expectancy of at least 10 years.
• The decision to initiate low-dose aspirin use for the primary prevention of cardiovascular disease in adults aged 60 to 69 who have a 10% or greater 10-year cardiovascular disease risk should be an individual one. Hemorrhage risk is increased in this older age group, making overall benefit less.
• The current evidence is insufficient to assess the overall primary prevention benefits versus harms of aspirin in adults aged 70 or older.
Clearly, not all middle-aged men and women are currently recommended by the task force policy to be on aspirin, especially those of low or average cardiovascular risk. However, recent studies discourage its use even further.
Several large newer studies have cast doubt almost completely on aspirin's primary prevention value.
In one study, patients older than 70 receiving aspirin received no benefit in reducing cardiovascular disease, disability or mortality but did have an increased risk of major hemorrhage.
A second study demonstrated no decrease in cardiovascular or cerebrovascular events but did show an increase in gastrointestinal bleeding in people with multiple cardiovascular risk factors who had not actually suffered a stroke or heart attack.
A third study found a decrease in cardiovascular events of 12% in diabetics but an increase in major bleeding events of 29%, greatly outweighing any benefits.
Additionally, there have been two meta-analysis studies (a study combining the results of many studies). The first meta-analysis found there was no overall benefit of aspirin therapy.
Although there was a decrease of 11% in cardiovascular events, this benefit was counterbalanced by an increase in major hemorrhagic events.
In the second meta-analysis, those taking aspirin had no decrease in all-cause and cardiovascular mortality as well as stroke, but heart attacks decreased by 18%. But once again, the benefit was counterbalanced by large increases in major bleeding events including cerebral hemorrhages.
So, study results vary, but the prevailing feeling is that aspirin should no longer be routinely recommended for primary prevention of cardiovascular disease and should be a case-by-case decision based on cardiovascular and bleeding risks. Remaining unresolved is aspirin use in high-risk patients who have demonstrated vascular disease but have not had a cardiovascular event.
Remember, aspirin definitely remains the cornerstone of secondary prevention.
Seek advice from your health-care provider before initiating or terminating preventive aspirin use.
Dr. Richard Feldman is former Indiana state health commissioner and senior medical education adviser for Franciscan Health Indianapolis.