BBC News reports that “low-dose aspirin should NOT routinely be used to prevent heart attacks and strokes,” according to research published in the Lancet. So, if you are on a daily aspirin for primary prevention of a heart attack or stroke, should you stop taking it?
The answer is not an easy one and I recommend you not make the decision alone – but, be sure to talk to your doctor about your individual risks and benefits of taking a daily aspirin (after being sure that he or she is up to date on this new information).
Professor Colin Baigent, the lead researcher for the study, told BBC News, “We don’t have good evidence that, for healthy people, the benefits of long-term aspirin exceed the risks by an appropriate margin.”
WebMD pointed out that investigators “conducted an analysis” that “included six high-quality primary-prevention studies with a combined enrollment of 95,000 low-to-average-risk people and 16 secondary-prevention studies with a combined enrollment of 17,000 high-risk patients.”
The UK’s Daily Mail explains that the researchers “found that healthy people who take aspirin reduced their already small risk of heart attack or stroke by 12 percent, while the small risk of internal bleeding increased by a third.”
According to the Daily Mail, “this means there were five fewer non-fatal heart attacks for every 10,000 people treated, but this was offset by a comparable increase in bleeding – one extra stroke and three cases of stomach bleeding per 10,000 people treated.”
Meanwhile, “in the secondary prevention studies – where patients were taking aspirin to prevent a repeat attack – aspirin reduced the chances of serious vascular events by about one-fifth and this benefit clearly outweighed the small risk of bleeding.”
Based on incremental cost effectiveness, they recommended aspirin for the following:
MedPage Today also covered the story and told doctors, “Explain to interested patients that primary prevention attempts to avoid cardiovascular events in people who do not have heart disease, whereas secondary prevention is begun after someone has a coronary event.”
MedPage added, “Note that U.S. Preventive Services Task Force and American Heart Association guidelines recommend aspirin for primary prevention in patients at moderately elevated risk for heart disease.”
In the meantime, Prescribers Letter is recommending the following to doctors:
Last, but not least, here are the current USPSTF guidelines:
And, for doctors:
Number Needed to Treat/Harm (for doctors)
Aspirin use for the primary prevention of cardiovascular disease provides more benefits than harms in men or women whose risk for myocardial infarction or ischemic stroke, respectively, is high enough to outweigh the risk for gastrointestinal hemorrhage.
In men similar to those enrolled in the RCTs, the number needed to treat to prevent 1 myocardial infarction over 5 years of aspirin use is 118, whereas the number needed to treat to cause 1 major bleeding event is 303 over 5 years of aspirin use and 769 to cause 1 hemorrhagic stroke.
The balance of benefits and harms varies by coronary heart disease risk and risk for gastrointestinal bleeding.
For a hypothetical group of 1000 men younger than 60 years with a 6% 10-year baseline risk for myocardial infarction, aspirin use will prevent approximately 19 myocardial infarctions and cause approximately 1 hemorrhagic stroke and 8 major bleeding events.
The USPSTF concluded with high certainty that the net benefit is substantial in men at increased risk for myocardial infarctions and not at increased risk for serious bleeding.
In women similar to those enrolled in the RCTs, the number needed to treat to prevent 1 ischemic stroke with 5 years of aspirin use is 417, and the number needed to treat to cause 1 major bleeding event is 392 over 5 years of aspirin use.
The balance of benefits and harms varies by stroke risk and risk for a bleeding event.
In a hypothetical group of 1000 women younger than 60 years with a 6% 10-year risk for stroke, aspirin use will prevent approximately 10 strokes and cause approximately 4 major bleeding events.
The estimates of the number of major bleeding events were assumed to be stable within age strata with respect to increases in baseline stroke risk.
The USPSTF concluded with high certainty that the net benefit is substantial for women at increased risk for stroke and not at increased risk for serious bleeding.