Study Links Aspirin to Reduced Severity in Atherosclerotic Stroke

Pre-stroke aspirin has been associated with reduced stroke severity.

Pre-stroke aspirin use has been linked to reduced severity in atherosclerotic stroke and lower disability scores despite a higher rate of hemorrhagic transformation in a cohort of patients.

“Aspirin may reduce stroke severity, at least for atherosclerotic stroke, and improve functional outcome even when it fails to prevent stroke. The role of aspirin might be assessed considering not only lower incidence of cardiovascular events but also lesser severity and better outcome by pre-event aspirin use,” Jong-Moo Park MD, PhD, of the Department of Neurology at Eulji General Hospital at Eulji University in Seoul, Korea, noted in an email to Neurology Advisor.

According to the paper published in the Annals of Neurology, aspirin is known to be beneficial to people at high risk for cardiovascular disease and stroke, and may be associated with lower stroke severity. However, there are little data comparing the benefits of aspirin in stroke severity with the risk of hemorrhagic transformation.

Park and colleagues collected retrospective data from the Clinical Research Center for Stroke-5th Division registry database on patients with large artery atherosclerosis, small vessel occlusion, or cardioembolic subtypes of acute ischemic stroke to assess the impact of pre-stroke aspirin on severity, rate of hemorrhagic transformation, and functional outcome.  In total, they identified 1914 study participants who reported aspirin use within a week prior to the stroke (18.3% of 10,433). On analysis, pre-stroke aspirin users were found to have a higher National Institutes of Health Stroke Scale (NIHSS) score initially (6.05 vs 5.69, mean difference 0.35; 95% confidence interval [CI]: 0.04-0.66) than non-aspirin users. However, after multivariable analysis the NIHSS score was lower in the pre-stroke aspirin users (-0.61; 95% CI: -0.89 to -0.34). Further, when analyzed based on stroke subtype, the initial NIHSS score was also lower in aspirin users with the large artery atherosclerosis type (6.91 vs 7.88, mean difference -0.97; 95% CI: -1.43 to -0.50). This was not the case for cardioembolic and small vessel occlusion stroke subtypes. 

Participants with a history of aspirin use were found to have a higher percentage of hemorrhagic transformation than non-aspirin users (7.4% vs 4.3%; P<.001). Likewise, after adjustment the investigators found an increased risk of hemorrhagic transformation with pre-stroke aspirin use (aOR 1.34; 95% CI: 1.05-1.73). 

Finally, modified Rankin Scales were calculated to assess functional disability and participants with pre-stroke aspirin use demonstrated lower median scores (aOR 0.86).  Post-hoc analysis further demonstrated “pre-stroke aspirin use decreased the odds of worse functional outcome (a higher mRS score) at discharge despite an increased risk of hemorrhagic transformation at presentation.” 

The study was funded by the Korea Healthcare technology R&D Project, the Ministry of Health and Welfare of the Republic of Korea, and Bayer Korea.

Dr Gorelick reported relationships with a Bayer-sponsored trial and New Haven Pharmaceuticals.


  1. Park JM, Kang K, Cho YJ, et al; on behalf of the CRCS-5 Investigators. Comparative effectiveness of pre-stroke aspirin on stroke severity and outcome. Ann Neurol. 2016; Jan 11. doi: 10.1002/ana.24602. [Epub ahead of print]