Objective
To investigate the association of low hemoglobin levels at admission with incidence of cognitive impairment after acute ischemic stroke, this study was conducted. Furthermore, we will also identify the relationship between hemoglobin parameters and specific cognitive subdomain.
Methods
We retrospectively recruited 217 patients with first-ever stroke during the period of January, 2017 through May, 2020. The patients diagnosed with ischemic stroke through brain imaging with computed tomography (CT) or magnetic resonance imaging (MRI) and who underwent a medical examination by blood tests, and detailed neuropsychological assessments were enrolled in this study.
The exclusion criteria were as follows: 1) Primary hemorrhagic stroke or transient ischemic attack; 2) transfer to rehabilitation department after 30 days from onset; 3) Mini-mental state examination (MMSE) scores of less than 10 and 4) Severe aphasia or dysarthria. Finally, 131 patients were available for analysis.
First, the subjects were classified into two groups based on MMSE scores(using cut-off points of 24). Demographics, lesion locations, National Institutes of Health Stroke Scale score(NIHSS), delta-MMSE(follow-up minus baseline), Initial Hb and delta-Hb(follow-up minus baseline) were compared between them using a two-tailed Student’s T test and a χ2 test.
Second, the subjects were classified into two groups based on admission Hb levels; anemic and non-anemic group. Specific cognitive subdomain score measured by detailed neuropsychological assessments were compared between them using a Mann-Whitney U test.
Finally, relationship between hemoglobin parameters and specific cognitive subdomain was analyzed by the Pearson's correlation coefficient.
Results
Demographic data and clinical characteristics of the enrolled patients are displayed in Table 1. Compared with patients without poststroke cognitive impairment(PSCI), patients with PSCI were more likely to be female and older. Besides, patients with PSCI also had lower educational levels, higher NIHSS score, and lower initial Hb concentration.
Compared with non-anemic patients, anemic patients had lower full scale intelligence quotient(FSIQ) score, and lower cognitive subsets scores. (Table 2).
Correlation analysis showed that initial MMSE score and cognitive subsets, especially Boston naming test(BNT), Rey-Kim memory test(RKMT), contrast test were correlated with initial Hb concentration. (Table 3).
Conclusion
This study demonstrated that low hemoglobin levels were associated with PSCI in patients with acute ischemic stroke. Moreover, even after adjusting age, education, BMI, Time to rehabilitation admission(TTR) and NIHSS, specific cognitive subdomains such as memory, language and executive function has a significant correlation with initial Hb concentration. It might be somewhat associated with the brain hypoxia, mitochondrial dysfunction, and neuronal injury that low Hb level may lead. |
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Table 1. Clinical and Demographic Characteristics
Table 2. Comparison of Cognitive measures between anemic and non-anemic patients
Table 3. Pearson Correlation Between Hemoglobin and Cognitive Measures by Gender Adjusted for Age, Education, BMI, TTR and NIHSS
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