How Does a Stroke Affect Cognitive Function? Interview with:

Sarah Parish, MSc, DPhil Professor of Medical Statistics and Epidemiology MRC Population Health Research Unit Nuffield Department of Population Health University of Oxford

Dr. Parish

Sarah Parish, MSc, DPhil
Professor of Medical Statistics and Epidemiology
MRC Population Health Research Unit
Nuffield Department of Population Health
University of Oxford What is the background for this study?

Response: Acquiring reliable randomized evidence of the effects of cardiovascular interventions on cognitive decline is a priority. In this secondary analysis of 3 randomized intervention trials of cardiovascular event prevention, including 45 029 participants undergoing cognitive testing, we estimated the association of the avoidance of vascular events with differences in cognitive function in order to understand whether reports of non-significant results exclude worthwhile benefit. What are the main findings?

Response: We found that incident stroke was associated with a cognitive function difference equivalent to that occurring with 7 years of aging; and incident transient ischemic attack, myocardial infarction, heart failure and new onset diabetes were associated with 1-2 years of cognitive aging.

Two of the trials had not achieved statistically significant reductions in their primary cardiovascular outcomes, but in the Heart Protection Study randomization to statin therapy for 5 years had resulted in 2.0% of survivors avoiding a non-fatal stroke or transient ischemic attack and 2.4% avoiding a non-fatal cardiac event. We showed that this yielded an expected reduction in cognitive aging of 0.15 years.

However, with 15 926 cognitively assessed participants, HPS only had good power (80%) to detect a larger, 1 year (i.e., 20% over the 5 years) difference in cognitive aging. What should readers take away from your report?

Response: Non-significant findings, even from large trials, should not be taken as good evidence for a lack of worthwhile benefit on cognitive function of prolonged use of cardioprotective therapies. What recommendations do you have for future research as a result of this work?

Response: Novel strategies to assess decline in cognitive function more precisely that are feasible for use in large-scale randomized trials may allow direct evidence about the benefits of cardiovascular interventions to emerge. 

Disclosures: This work was supported by grants from Merck, Roche, the U.K. Medical Research Council, the British Heart Foundation, and Cancer Research U.K. to the University of Oxford.  


Offer A, Arnold M, Clarke R, et al. Assessement of Vascular Event Prevention and Cognitive Function Among Older Adults With Preexisting Vascular Disease or DiabetesA Secondary Analysis of 3 Randomized Clinical TrialsJAMA Netw Open. 2019;2(3):e190223. doi:10.1001/jamanetworkopen.2019.0223


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