People aged 50 to 69 years who have a 10% or greater 10-year risk for cardiovascular disease (CVD) and who do not have higher risk for bleeding should consider taking low-dose aspirin to help prevent CVD and colorectal cancer, according to final recommendations from the US Preventive Services Task Force (USPSTF).
Full recommendation and evidence reviews were published online April 12 in the Annals of Internal Medicine.
Medscape Medical News previously reported on the draft recommendations issued in September.
People considering starting an aspirin regimen should have a life expectancy of at least 10 years and be willing to take the low-dose aspirin (≤100 mg/day) for at least 10 years, according to the guidance, written by Albert L. Siu, MD, MSPH, on behalf of the task force.
The decision should be an individual one made in consultation with a physician. Taking aspirin daily can help prevent heart attacks, ischemic stroke, and cancer, but it also increases the risks for serious harms, especially bleeding in the stomach and intestines and hemorrhagic strokes.
The researchers found that in current practice, among those eligible for aspirin therapy and at increased CVD risk, "about 41% were told by a physician to take aspirin." Among those aged 65 years or older who were told to take aspirin, 80% adhered to the recommendation.
Some adults may decide that avoiding a myocardial infarction or a stroke is more important to them than risking a gastrointestinal bleeding event and may decide to take aspirin at a lower CVD risk level than those more worried about bleeding, the authors write.
The task force took the unusual step of commissioning a simulation modeling study to analyze the benefits and harms based on age, sex, and CVD risk and weighed the results with three evidence reviews, also published in the journal, before finalizing a recommendation.
Which Groups Benefit Most?
The modeling paper, by Steven P. Dehmer, PhD, from the HealthPartners Institute in Minneapolis, Minnesota, and colleagues, found that a lifetime aspirin regimen is expected to reduce illness for most men and women without higher risk of bleeding (eg, history of gastrointestinal ulcers, recent bleeding, or use of medications that increase bleeding risk) and have the most benefit when people start taking it early, at ages 40 to 69 years.
Such a regimen is also likely to increase life expectancy for most men and women who start it at ages 40 to 59 years and for those who have elevated CVD risk who start taking aspirin at ages 60 to 69 years.
For those in their 70s whose 10-year CVD risk is 20% or less, the researchers found, the overall benefits do not outweigh the harms. In addition, there was not enough primary evidence to make a recommendation on aspirin use for people younger than 50 years. More research is needed before determining guidance for these age groups.
Aspirin helps prevent CVD because it can decrease the blood clots that form from reduced blood flow at atherosclerotic plaques and reduce hypoxic damage to heart and brain tissue. The mechanisms for preventing colorectal cancer development are not yet well-understood, but may result from aspirin's anti-inflammatory benefits, the authors write.
Finding effective prevention for CVD and cancer is critical. In 2011, the authors note, more than half of all deaths in the United States were caused by heart disease, stroke, or cancer, and colorectal cancer is a leading cause of cancer death.
These recommendations update the 2009 USPSTF recommendation on aspirin use to prevent CVD, as well as the 2007 recommendation on aspirin in preventing colorectal cancer.
The task force says it recognizes that although physicians need to understand the evidence, they also have other considerations when recommending treatments for an individual patient.
The authors report a contract with the Agency for Healthcare Research and Quality during the conduct of the study.
Ann Intern Med. Published online April 12, 2016.