SNOWMASS, COLO. – during the space of a few short weeks in autumn 2018.
“Is aspirin safe and effective for primary prevention? The short answer here is no,” Patrick T. O’Gara, MD, declared at the annual Cardiovascular Conference at Snowmass sponsored by the American College of Cardiology.
“Think of all those decades of aspirin therapy in the hopes of making ourselves healthier,” added Dr. O’Gara, professor of medicine at Harvard Medical School, Boston, and a past president of the American College of Cardiology.
He cited the results of three placebo-controlled randomized trials totaling more than 47,000 patients without known cardiovascular disease: ARRIVE, published in late September 2018, followed in October by ASPREE and ASCEND.
• ARRIVE. This double-blind study conducted in seven countries included 12,546 patients deemed at moderate cardiovascular risk, with an estimated 10-year cardiovascular event risk of 17%. Eligibility was restricted to men aged 55 and up and women aged 60 or older. After a median follow-up of 5 years, there was no difference between patients assigned to enteric-coated aspirin at 100 mg/day versus placebo in the incidence of major adverse cardiovascular events, with a hazard ratio of 0.96. However, GI bleeding events were 2.1-fold more common in the aspirin group ().
• ASPREE. This double-blind trial, conducted in Australia and the United States, included 19,114 community-dwelling participants aged 70 years or older, or 65 years or older for Hispanics and blacks in the United States. After a median 4.7 years of follow-up, there was no difference in major adverse cardiovascular events between subjects randomized to 100 mg/day of enteric-coated aspirin and those on placebo. So, as in ARRIVE, no benefit. However, the rate of major hemorrhage was 38% greater in the aspirin group (.
Moreover, the rate of all-cause mortality was 14% greater in the aspirin group, a statistically significant difference, compared with controls. Drilling down, the investigators showed that the major contributor to this excess mortality in the aspirin group was their 31% greater rate of cancer-related death ().
“Remember, we used to think that taking aspirin reduced the incidence of GI cancer, and, in particular, colon adenocarcinoma? Well, here’s a very startling observation in 19,114 healthy elderly patients showing an increase in cancer-associated death with the use of aspirin,” commented Dr. O’Gara.
• ASCEND. This study randomized 15,480 subjects with diabetes but no known cardiovascular disease to 100 mg/day of aspirin or placebo and followed them for a mean of 7.4 years. There was a significant 12% relative risk reduction in the composite endpoint of serious vascular events in the aspirin group; however, the aspirin-treated patients also had a 29% greater rate of major bleeding events ().