Baseline cognitive function, recurrent stroke, and risk of dementia in patients with stroke.

BACKGROUND AND PURPOSE To determine the interrelationships between baseline Mini-Mental State Examination (MMSE) score and risk of overall dementia, post-recurrent stroke dementia, and dementia without recurrent stroke among patients with a history of stroke. METHODS Prospective cohort study among participants enrolled in the Perindopril Protection Against Recurrent Stroke Study (PROGRESS) for whom baseline MMSE score was available. Baseline MMSE score was divided into 4 categories: 30, 29-27, 26-24, and <24. Participants were followed for incident dementia and recurrent stroke. Logistic regression models were used to examine the association between MMSE score and dementia. RESULTS Of the 6080 participants included in this analysis, 2493 had an MMSE score of 30, 1768 had a score of 29-28, 1369 had a score of 26-24, and 450 had a score of <24. Average follow-up time was 3.8 years. There were 407 cases of dementia, 106 of which were preceded by a recurrent stroke. The risk of overall dementia increased with decreasing MMSE score. However, the impact of MMSE score on the risk of dementia without recurrent stroke was much stronger than the impact of MMSE score on the risk of post-recurrent stroke dementia. For those with MMSE score <24, the risk of dementia without recurrent stroke was 47.89 (95% confidence interval, 28.57-80.26), whereas the risk of post-recurrent stroke dementia was only 7.17 (95% confidence interval, 3.70-13.89). Higher MMSE scores were even less strongly associated with the risk of post-recurrent stroke dementia. CONCLUSIONS Patients with stroke with low MMSE scores are at high risk of dementia over time, even in the absence of a recurrent stroke, and should therefore be followed closely for further cognitive decline.