Daily low-dose aspirin has little impact on stroke risk and spikes risk of brain bleeding from falls

Low-dose daily aspirin does not provide significant protection against stroke resulting from blood clots and may increase risk of bleeding in the brain or skull after head trauma, according to an NIA-funded study. The findings, published in JAMA Network Open, provide new evidence countering past conventional wisdom recommending a daily low-dose or baby aspirin for healthy older adults.

In this study, an international team led by Australian researchers analyzed data from the ASPirin in Reducing Events in the Elderly (ASPREE) trial. ASPREE includes about 19,000 healthy older adult volunteers from Australia and the United States who were randomly assigned to take a daily 100 milligram aspirin or a placebo pill and were monitored for approximately five years.

The research team found no statistically significant difference in stroke incidence between those who took aspirin and those on the placebo. While a relatively small overall number of brain bleeds occurred in participants during the study period — 187 total, with 108 from the aspirin group and 79 from the placebo one — bleeding events were 38% higher among participants who were taking aspirin daily, regardless of their gender, age, or cardiovascular risk. Bleeding into the brain or onto its surface are common and serious results of fall-related head injuries in older adults. In this study, nearly half of these bleeding events were due to trauma.

In a related recent study, the ASPREE team also found that daily aspirin could increase anemia risk in older adults. In 2022, in part due to ASPREE findings, the U.S. Preventive Services Task Force updated its past recommendations to state that healthy adults age 60 or older should not start taking low-dose aspirin as a primary prevention strategy for cardiovascular disease. These recommendations do not apply to individuals taking aspirin for a known cardiovascular condition.

The ASPREE investigators view these recent results as further evidence that healthy older adults with no history of stroke or cardiovascular disease should talk with their doctors about the potential risks and benefits when considering taking aspirin daily. They further note that older adults who have had past strokes or are in higher risk groups for cardiovascular disease may still benefit from aspirin’s blood thinning effects, so these individuals should also ask about the benefits of aspirin versus other drugs such as statins.

This research was supported in part by NIA grants AG029824 and AG062682.

References: Cloud GC, et al. Low-dose aspirin and the risk of stroke and intracerebral bleeding in healthy older people: Secondary analysis of a randomized clinical trial. JAMA Network Open. 2023;6(7):e2325803. doi:10.1001/jamanetworkopen.2023.25803.

McQuilten ZK, et al. Effect of low dose aspirin versus placebo on incidence of anemia in the elderly: An analysis of the ASPirin in Reducing Events in the Elderly trial. Annals of Internal Medicine. 2023;176(7):913-921. doi: 10.7326/M23-0675.