A large study from Japan shows no significant protective effect of low-dose aspirin against cardiovascular mortality among people with risk factors (but no prior CVD history). Now what should doctors advise?
Published in JAMA in time to coincide with a presentation at the current American Heart Association meetings, a new controlled trial seeking aspirin s protective effect against cardiovascular disease (CVD) failed to show any benefit in terms of mortality among a large cohort of Japanese patients with risk factors.
The study authors, a group based at Waseda University in Tokyo led by Yasuo Ikeda, MD, followed 14,464 patients aged between 60 and 85 who had one or more of these CVD risk factors: high blood pressure, diabetes, lipid abnormalities and gave half of them 100 mg of aspirin (in addition to their other prescribed medications) and compared CVD outcomes to the other (control) group. After 5 years, the study s monitors stopped it, as they had determined that there was and would be no significant difference between the aspirin and no aspirin groups. (There was some benefit seen in the incidence of nonfatal heart attack and TIA transient stroke but this was balanced by increased bleeding risk).
Since the study subjects had no prior CVD history, this approach would be termed primary prevention, while if the study involved subjects with prior CVD history it would have been secondary prevention.
Michael Gaziano, M.D., M.P.H., of the Veterans Affairs Boston Healthcare System, Brigham and Women's Hospital, Harvard Medical School, Boston, and Associate Editor, JAMA, and Philip Greenland, M.D., of the Northwestern University Feinberg School of Medicine, Chicago, and Senior Editor, JAMA, write in an accompanying editorial that the findings from this study add to the body of evidence that helps refine the answer to the question of when aspirin should be used to prevent vascular events.
"Decision making involves an assessment of individual risk-to-benefit that should be discussed between clinician and patient. However, at present the choice of aspirin remains clear in several situations. Aspirin is indicated for patients at high short-term risk due to an acute vascular event and those undergoing certain vascular procedures; patients with any evidence of vascular disease should be given daily aspirin. On the other hand, patients at very low risk of vascular events should not take aspirin for prevention of vascular events, even at low dose. However, some individuals who do not have overt vascular disease will have risk levels that approach those of patients with CVD (such as patients with multiple risk factors). It remains likely that there is some level of risk of CVD events that would result in a positive trade-off of benefit and risk for the use of aspirin, but the precise level of risk is uncertain."
ACSH s Dr. Gil Ross adds, This may sound very complicated but the takeaway message, as the editorial pointed out, is that the decision about whether or not to take aspirin for primary prevention should involve a discussion with your doctor.