Dr. Wong added: “Two didn’t find any significant reductions in heart attack or stroke, but there was an increased risk of bleeding.” The third clinical trial, which was limited to people with diabetes, a higher-risk group, found a small reduction in cardiovascular events — but with a higher bleeding risk. “The harm canceled out the benefit,” Dr. Wong said.
The bleeding in question usually occurs in the gastrointestinal tract but can also include brain bleeds and hemorrhagic strokes. Although the risks are low — major bleeding occurred in 1 percent or fewer of older people taking aspirin in the 2018 studies — they increase with age. “These are serious bleeds,” Dr. Brett said. “They can require transfusions. They can put people in the hospital.”
With the advent of other effective advances in preventing heart attacks and strokes — better blood pressure drugs, statins for lowering cholesterol, a reduction in smoking — the role for aspirin has narrowed, experts said.
For people over 60, per the task force guidelines, or 70, per the cardiologists’ recommendations, the risks of starting aspirin now outweigh the benefits. This is particularly true for people with a history of bleeding, say from ulcers or aneurysms, or those taking medications like blood thinners, steroids or anti-inflammatories such as ibuprofen or naproxen.
The 2016 task force recommendation raised the possibility that aspirin might play a role in preventing colon cancer. But, Dr. Wong said, “we’re no longer confident aspirin provides benefit for colorectal cancer. We don’t have enough evidence. We’re calling for more research.”
The task force had frustratingly little to say, however, about people over 60 stopping aspirin if they have already begun taking it for primary prevention. It mentioned that people should consider stopping at about age 75 because any benefit would diminish with age, but it also said patients should not discontinue aspirin without talking to a health care professional.
“There’s no urgency,” Dr. Khera said. “Put this on the agenda of things to discuss” at an upcoming appointment. But, he added, “for people generally healthy, with few risk factors, it’s reasonable to just stop.” Dr. Brett said he had been cautioning patients against routine aspirin use since 2018.