Aspirin primary prevention heart attack guidelines have shifted significantly in recent years, creating confusion among patients and clinicians alike. While daily aspirin has long been used to prevent first time heart attacks and strokes, new draft guidelines from the United States Preventive Services Task Force have raised important questions about who should actually be taking it — and who may be taking on more risk than benefit.
Secondary vs. Primary Prevention: What Is the Difference?
For people who have already experienced a heart attack or stroke, the evidence is clear. A daily aspirin regimen reduces the risk of future cardiovascular events. For every 100 patients with a history of heart attack or stroke who stay on daily aspirin, five recurrent events are prevented in a single year. The risk of serious bleeding — fewer than one in 100 patients — is far outweighed by the benefit.
But aspirin primary prevention heart attack use — meaning using aspirin to prevent a first event in someone with no cardiovascular history — is a different matter entirely. Here, the balance between benefit and risk is much less straightforward.
What Do the New Guidelines Say?
The updated draft guidelines from the Preventive Services Task Force recommend daily aspirin for adults between 50 and 59 years old who have at least a 10% ten year risk of a heart attack or stroke as calculated by a standard risk tool.
For adults between 60 and 69, the task force says there is less benefit but that aspirin may still be appropriate if the risk of bleeding is low. For patients younger than 50 or older than 70, the task force found insufficient evidence to make any recommendation — a significant departure from the 2009 guidelines that covered all adults between 45 and 79 with elevated cardiovascular risk.
Aspirin Primary Prevention Heart Attack: What the Data Show
For middle aged adults with no cardiovascular history, the data reveal a near equal trade off between benefit and harm. According to the task force’s own calculations, for every 100 men between 55 and 60 with an average first event risk of 1% per year, starting daily aspirin would over a lifetime prevent roughly two heart attacks and one stroke — but would also cause approximately three serious stomach bleeds and one hemorrhagic stroke.
This near equivalence is why aspirin primary prevention heart attack decisions cannot be made with a one size fits all approach.
Where Major Guidelines Disagree
Not all medical organizations agree. The American Heart Association, American College of Cardiology, and American Diabetes Association all endorse aspirin for primary prevention in certain higher risk patients. The FDA, however, denied a petition from aspirin manufacturer Bayer to add labeling stating aspirin could prevent first time heart attacks and strokes. And the European Society of Cardiology does not endorse aspirin for primary prevention for any patient, even those at high risk.
This lack of consensus is reflected in real world behavior. A national survey published in 2015 found that nearly half of all U.S. adults without cardiovascular disease reported regularly using aspirin as a preventive therapy.
Aspirin Primary Prevention Heart Attack: What Patients Should Do
If you are over 40 and have no history of cardiovascular disease, the first step is to check your predicted 10 year cardiovascular risk. If your risk exceeds 10%, speak with your doctor about whether daily aspirin is appropriate for you. Patients with no elevated bleeding risk may be reasonable candidates, but the odds of a serious bleed are roughly equal to the odds of preventing a heart attack or stroke — a trade off not every patient will want to accept.
For patients under 70 with a cardiovascular risk below 10%, aspirin therapy should generally be avoided.
The evidence base for aspirin primary prevention continues to evolve. Community based clinical research plays a critical role in generating the large, long term randomized trial data needed to give clinicians and patients clearer answers. Learn more about ongoing cardiovascular research on our blog or explore our services.
For the full original article, see the source at The Conversation.
Source: The Conversation | Originally published January 6, 2016