September 16, 2019
By Megan Brooks
NEW YORK (Reuters Health) - The benefit of aspirin therapy may outweigh the bleeding risk for some adults who do not have heart disease, and these individuals can be identified using a personalized benefit-harm analysis, according to a new study.
Whether the benefits of aspirin for preventing cardiovascular disease (CVD) outweigh its bleeding risk remains unclear. To investigate, researchers from the University of Auckland, in New Zealand, did an individualized benefit-harm analysis in more than 245,000 adults (43.6% women) aged 30 to 79 years without established CVD to try to identify those people who would likely derive a net benefit from aspirin therapy.
They calculated the net effect of aspirin treatment over five years for each individual by subtracting the number of CVD events aspirin would likely prevent from the number of major bleeding episodes likely to occur on aspirin. The data came from PREDICT, a well-characterized web-based decision support program integrated with electronic primary-care-practice management systems in New Zealand.
In this CVD-free cohort, the researchers determined that 2.5% of women and 12.1% of men were likely to derive net benefit from aspirin treatment for five years. These percentages rose to 21.4% of women and 40.7% of men when one CVD event was assumed to be "equal" to two major bleeds.
"Net benefit sub-groups had higher baseline CVD risk, higher levels of most established CVD risk factors, and lower levels of bleeding-specific risk factors than net harm subgroups," report Dr. Vanessa Selak and colleagues in Annals of Internal Medicine, online September 16.
"In order to decide whether or not to initiate aspirin for the primary prevention of CVD, personalized assessment of the expected benefits (CVD events avoided) and harms (serious bleeds caused) of aspirin is needed, and should be used by doctors as the basis of their discussions with patients," Dr. Selak told Reuters Health by email.
"We have developed a web-based calculator (https://aspirinbenefitharmcalculator.shinyapps.io/calculator/) that provides doctors with individualized estimates of the benefits and harms of aspirin for New Zealand patients. Calculators like these can be used to support doctors in their discussions with patients who will ultimately need to decide whether or not to take aspirin for the primary prevention of CVD," said Dr. Selak.
In an editorial published with the study, Dr. John Kostis from the Cardiovascular Institute, Rutgers Robert Wood Johnson Medical School, in New Brunswick, New Jersey, cautions that the study findings may not apply to populations outside New Zealand. Also, the study did not include people over the age of 79.
The diversity of findings in several aspirin studies make it tough to establish firm, evidenced-based recommendations for aspirin use in primary prevention, Dr. Kostis says.
Nonetheless, "it seems reasonable to recommend aspirin for the primary prevention of CVD in select patients, including those who are at high risk for CVD, provided that the bleeding risk is low, as evidenced by a history of bleeding and comorbid conditions," he concludes.
Funding for the study was provided by the Health Research Council of New Zealand.
Ann Intern Med 2019.
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