Aspirin fails to improve CV outcomes, raises hemorrhage risk in older adults
Among older adults, low-dose aspirin did not reduce CVD risk vs. placebo and conferred an increase in risk for major hemorrhage, according to results of the ASPREE trial.
ASPREE is the third major aspirin trial to report primary prevention results recently. As Cardiology Today previously reported at the European Society of Cardiology Congress, in the ASCEND trial of patients with diabetes, aspirin lowered risk for vascular events but increased bleeding risk, and in the ARRIVE trial of participants without diabetes and at moderate risk, aspirin did not significantly reduce initial vascular events vs. placebo.
For ASPREE, primarily funded by the NIH, the researchers enrolled 19,114 patients from the United States and Australia aged at least 70 years ( 65 years in U.S. patients with black race or Hispanic ethnicity) without CVD, dementia and disability at baseline. All participants (44% men; 50% aged 74 years) were randomly assigned 100 mg per day enteric-coated aspirin or placebo.
The endpoints of interest included major hemorrhage and CVD, defined as fatal CHD, nonfatal MI, fatal or nonfatal stroke or HF hospitalization. Median follow-up was 4.7 years.
No difference in CVD events
During the study period, CVD events were similar between the aspirin group (10.7 events per 1,000 patient-years) and the placebo group (11.3 events per 1,000 patient-years; HR = 0.95; 95% CI, 0.83-1.08), John J. McNeil, MB, BS, PhD, from the department of epidemiology and preventive medicine at Monash University, Melbourne, Australia, and colleagues wrote in The New England Journal of Medicine.
Major hemorrhage occurred more often in the aspirin group (8.6 events per 1,000 person-years vs. 6.2 events per 1,000 person-years; HR = 1.38; 95% CI, 1.18-1.62), according to the researchers.
Low event rates
“On the basis of the results of previous trials, it was anticipated that benefits of aspirin treatment might arise from a reduction in the rate of cardiovascular events,” McNeil and colleagues wrote. “However, in this trial, the rate of ... cardiovascular disease (a composite that accounted for all cardiovascular events, including stroke due to intracranial hemorrhage and hospital admission for cardiac failure) was not significantly lower with low-dose aspirin than with placebo.”
Event rates being lower than expected may have played a role in the findings, McNeil and colleagues wrote.
“In the trial protocol, the anticipated rate was 22.4 events per 1,000 person-years,” they wrote. “The observed rate was approximately half this estimate, most likely reflecting the relatively good health of the participant population at recruitment and the declining rate of cardiovascular disease in the two countries over time and across all age groups.”
The CVD results comprised one of three papers published in NEJM about findings from ASPREE. In one paper, the overall primary outcome of death, dementia or persistent physical disability was almost identical between the aspirin and placebo groups. In another, all-cause mortality was higher in the aspirin group, driven by cancer-related deaths. – by Erik Swain
Disclosures: The study was funded by the NIH’s National Institute on Aging and National Cancer Institute, the National Health and Medical Research Council of Australia, Monash University and the Victorian Cancer Agency. McNeil reports nonfinancial support from Bayer AG during the conduct of the study. Please see the study for all other authors’ relevant financial disclosures.