Aspirin Flops Again for Dementia Prevention

Affirming the ASPREE trial findings, daily aspirin failed to turn up a significant impact on dementia and cognitive function in an analysis of the ASCEND trial, but the analysis was unable to rule out a modest effect.

Among the some 15,000 diabetes patients in ASCEND, dementia was no less common for those randomized to aspirin or placebo, whether defined narrowly (3.3% vs 3.7%, respectively; RR 0.89, 95% CI 0.75-1.06) or broadly to also include cognitive impairment, delirium or confusion, use of dementia medications, and referral to a memory clinic or geriatric psychiatry (7.1% vs 7.8%; RR 0.91, 95% CI 0.81-1.02).

Cognitive scores were nearly identical between the two arms, Jane Armitage, MBBS, of the University of Oxford in England, reported at the virtual American Heart Association (AHA) meeting.

Still, the trial suggested little chance of cognitive harm from aspirin, but a plausible benefit in the 15-18% range, she said.

A 15% reduction in risk would be clinically relevant, noted AHA press conference moderator Christie Ballantyne, MD, of Baylor College of Medicine in Houston.

"Trials with larger numbers of incident dementia cases are needed to assess whether such benefits actually exist," Armitage concluded, although predicting that such trials would need to be roughly twice as large as ASCEND.

ASCEND was "really consistent" with the ASPREE trial's finding that daily use of aspirin in healthy adults over the age of 70 did not reduce dementia, mild cognitive impairment, or cognitive decline, noted Erin Michos, MD, MHS, of the Johns Hopkins School of Medicine and School of Public Health in Baltimore, who served as study discussant at the AHA press conference.

Main trial results from ASCEND had shown a reduction in major cardiovascular events with aspirin use, but an increase in major bleeding, such that there was no group for whom the benefits would clearly outweigh the risks, Armitage said when presenting those findings in 2018.

Looking at the dementia findings in context, Michos suggested that the best strategy may be to prevent cardiovascular events that have been tied to dementia through blood pressure and lipid control, cessation of smoking, and lifestyle measures. "Those might be more effective ways to prevent atherosclerotic cardiovascular disease and subsequently prevent dementia," she said.

And since studies have suggested midlife cardiovascular health strongly predicts later life cognition and dementia, Michos added, "as a prevention strategy, we need much more focus on improving the cardiovascular health of the population much earlier in life."

She cautioned, though, that U.S. Preventive Services Task Force draft recommendations against primary prevention aspirin use for older adults do not apply to those with established cardiovascular disease or prior events. American College of Cardiology/AHA guidelines also suggest only selective primary prevention use.

ASCEND included 15,480 patients in the U.K. who were age 40 or older and had any type of diabetes but no prior cardiovascular disease. They were randomized to 100-mg aspirin daily or placebo, and in a separate portion of the trial to either omega-3 fatty acids or placebo. Patients were followed for a mean 7.4 years on study drug and 1.8 years afterward through electronic medical records and hospital admissions.

Analyses were restricted to the 15,427 participants without any indication of dementia at baseline. Cognitive function testing done via telephone or online was available for 9,015 participants.

Comment