Low-dose aspirin not suitable for primary prevention of stroke in older adults and should be taken with caution: JAMA

The study, published in JAMA Network Open, found a statistically significant 38% increase in intracranial bleeding resulting from a combination of hemorrhagic stroke and other intracerebral haemorrhage causes among people randomized to aspirin. The difference in the incidence of ischemic stroke was not statistically significant. The findings may be particularly relevant to older people prone to intracranial bleeding development after head trauma.

"These data support the USPSTF recommendation that low-dose aspirin should not be prescribed for primary prevention in healthy older adults," the researchers wrote.

Aspirin is an antiplatelet agent that has been used in low doses of 75-100 mg/d for primary and secondary prevention of stroke. Despite some recent adverse findings, it continues to be used widely for primary and secondary prevention of stroke. Its major adverse effect is an increased tendency of bleeding.

In older individuals, the balance between the potential reduction of ischemic stroke events and increased intracranial bleeding has not been established. Geoffrey C. Cloud, Monash University, Melbourne, Australia, and colleagues aimed to establish the risks of ischemic stroke and intracranial bleeding among healthy older people receiving daily low-dose aspirin.

For this purpose, the researchers conducted a secondary analysis of the ASPREE randomized, double-blind, placebo-controlled trial of daily low-dose aspirin among community-dwelling people living in Australia or the US. Participants included older adults free of symptomatic cardiovascular disease (CVD). Recruitment was between 2010 and 2014 and followed up for a median of 4.7 years. 9525 individuals were randomized to daily 100-mg enteric-coated aspirin and 9589 individuals received matching placebo.

The researchers reported the following findings:

• Aspirin did not produce a statistically significant reduction in the incidence of ischemic stroke (hazard ratio [HR], 0.89).
• A statistically significant increase in intracranial bleeding was observed among individuals assigned to aspirin (1.1% individuals compared with those receiving placebo (0.8% individuals; HR, 1.38). This occurred by an increase in a combination of subdural, extradural, and subarachnoid bleeding with aspirin compared with placebo (0.6% versus 0.4% individuals; HR, 1.45).
• Hemorrhagic stroke was recorded in 0.5% of individuals assigned to aspirin compared with 0.4% of individuals in the placebo group (HR, 1.33).

"Our study found a significant rise in intracranial bleeding with daily low-dose aspirin but no significant reduction of ischemic stroke," the researchers wrote. "These findings are particularly relevant for older individuals prone to developing intracranial bleeding following head trauma."

Reference:

Cloud GC, Williamson JD, Thao LTP, 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 Netw Open. 2023;6(7):e2325803. doi:10.1001/jamanetworkopen.2023.25803