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Meta-Analysis
. 2014 Oct 7;186(14):E536-46.
doi: 10.1503/cmaj.140147. Epub 2014 Aug 25.

Cognitive impairment and risk of future stroke: a systematic review and meta-analysis

Meng Lee  1 , Jeffrey L Saver  1 , Keun-Sik Hong  1 , Yi-Ling Wu  1 , Hsing-Cheng Liu  1 , Neal M Rao  1 , Bruce Ovbiagele  2
Affiliations
Meta-Analysis

Cognitive impairment and risk of future stroke: a systematic review and meta-analysis

Meng Lee et al. CMAJ. .

Abstract

Background: Several studies have assessed the link between cognitive impairment and risk of future stroke, but results have been inconsistent. We conducted a systematic review and meta-analysis of cohort studies to determine the association between cognitive impairment and risk of future stroke.

Methods: We searched MEDLINE and Embase (1966 to November 2013) and conducted a manual search of bibliographies of relevant retrieved articles and reviews. We included cohort studies that reported multivariable adjusted relative risks and 95% confidence intervals or standard errors for stroke with respect to baseline cognitive impairment.

Results: We identified 18 cohort studies (total 121 879 participants) and 7799 stroke events. Pooled analysis of results from all studies showed that stroke risk increased among patients with cognitive impairment at baseline (relative risk [RR] 1.39, 95% confidence interval [CI] 1.24-1.56). The results were similar when we restricted the analysis to studies that used a widely adopted definition of cognitive impairment (i.e., Mini-Mental State Examination score < 25 or nearest equivalent) (RR 1.64, 95% CI 1.46-1.84). Cognitive impairment at baseline was also associated with an increased risk of fatal stroke (RR 1.68, 95% CI 1.21-2.33) and ischemic stroke (RR 1.65, 95% CI 1.41-1.93).

Interpretation: Baseline cognitive impairment was associated with a significantly higher risk of future stroke, especially ischemic and fatal stroke.

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Figures

Figure 1:
Figure 1:
Selection of studies for the meta-analysis.
Figure 2:
Figure 2:
Association between cognitive impairment at baseline and risk of future stroke. Values greater than 1.0 indicate an increased risk of stroke. *Study subgroups: a = ischemic, b = hemorrhagic, c = fatal and d = nonfatal stroke; e, e1, e2, and f represent different degrees of cognitive impairment reported in a study. CI = confidence interval.
Figure 3:
Figure 3:
Association between cognitive impairment at baseline defined by Mini-Mental State Examination score < 25 or nearest equivalent and risk of future stroke. Values greater than 1.0 indicate an increased risk of future stroke. *Study subgroups: a = ischemic, b = hemorrhagic; e, e1 and f represent different degrees of cognitive impairment reported in a study. CI = confidence interval.
Figure 4:
Figure 4:
Association between cognitive impairment at baseline and risk of future stroke, by type of stroke. Values greater than 1.0 indicate an increased risk of stroke. *Study subgroups: a = ischemic, b = hemorrhagic, c = fatal and d = nonfatal stroke; e and f represent different degrees of cognitive impairment reported in a study. CI = confidence interval.
See this image and copyright information in PMC

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