Doctors have recommended low-dose aspirin for prevention of heart attacks and stroke for so long, it's become an almost sacred health habit for plenty of patients.
But physicians need to rethink that advice given evidence from new studies, according to a new opinion piece.
In particular, they need to examine two recent studies when deciding whether to recommend that patients with no history of cardiovascular events take aspirin for primary prevention, wrote Michael Pignone, M.D., of Dell Medical School at the University of Texas in Austin and Darren A. DeWalt, M.D., of the University of North Carolina School of Medicine in Chapel Hill in the Annals of Internal Medicine.
The ASPREE (Aspirin in Reducing Events in the Elderly) trial showed a greater harm than benefit for initiating aspirin treatment in older adults but did not inform treatment for those who were receiving aspirin before age 70. The ASCEND (A Study of Cardiovascular Events in Diabetes) trial found that aspirin use was associated with a modest reduction in cardiovascular events and a modest increase in major bleeding risk.
Patients with no history of cardiovascular events probably derive small benefit from taking aspirin, Pignone and DeWalt said, despite the 2016 recommendation from the U.S. Preventive Services Task Force for the use of aspirin in adults age 50 to 59. The task force issued a moderate-strength, or “B,” recommendation for aspirin use in adults in that age group who are at risk for cardiovascular disease, are not at increased risk for bleeding, have a life expectancy of at least 10 years and are willing to take low-dose aspirin daily for at least 10 years.
“Although much is written about aspirin and many patients take it without a second thought, the overall magnitude of net benefit is likely small,” they wrote, noting that doctors should consider aspirin therapy after use of smoking cessation, statins and blood pressure control to lower patient risks.
Of course, doctors have long weighed the benefits of aspirin—including preventing cardiovascular events and possibly reducing the incidence and mortality of some types of cancer—with the harms such as the increased risk for gastrointestinal bleeding and stroke.
“In light of this new evidence, how should physicians approach the use of aspirin for primary prevention?” they asked. Among middle-aged adults with or without diabetes, the doctors said they believed an approach based on cardiovascular risk still holds. They said patients younger than 70 can take aspirin as an additional risk-reducing therapy if other therapies have been used and the patient still has elevated heart risk and no increased bleeding risk.
In most adults older than 70, with or without diabetes, doctors should not initiate aspirin therapy, they said, as the risk for bleeding increases and the evidence does not support a net benefit. At this time, the evidence is not clear whether to stop aspirin at age 70 if a patient already started the drug at an earlier age, they said, adding that they tend to continue it unless the bleeding risk has increased.
But as the authors noted, patients often take aspirin without a second thought and probably consider it safe. Doctors have recommended daily aspirin for so long it may be difficult to get patients to stop the practice even if the benefits are low or the risks high.