Abstract:

BACKGROUND: No international reports had shown that statins were effective for the treatment of vascular cognitive impairment. However, Chinese studies concerning effects of statins on vascular dementia had a small sample size, so no definite conclusion was obtained.
OBJECTIVE: To perform a meta-analysis on effects of statins on vascular cognitive impairment, the methods recommended by the Cochrane Collaboration were used.
METHODS: The databases such as China National Knowledge Internet, Wanfang, VIP, Chinese Biological and Medical Database and PubMed Medline were searched by computer and manually for randomized controlled trials about the effect of statins on vascular cognitive impairment. Retrieval time was from foundation to January 2013. The studies were screened according to the inclusion and exclusion criteria and then the data were extracted. The methodological quality of included studies was assessed and meta-analysis was performed by Revman 5 software. 
RESULTS AND CONCLUSION: This study finally included 15 randomized controlled trials, a total of 1 203 patients, including 616 in statins group and 587 in control group. The fixed and random effect models were used to analyze mini-mental state examination and activity of daily living scales including 14 scoring method and the Barthel index score. Compared with the control group, mini-mental state examination scores in the patients of statins group (14 randomized control trials, 1 112 patients) were, mean difference (MD)=3.02, 95% confidence interval (CI): 2.26 to 3.77, P < 0.000 1; activity of daily living scores (14 scoring method, 7 randomized controlled trials, 513 patients) were, MD=-4.14, 95% CI: -6.11 to -2.18, P < 0.000 1; the Barthel index scores (2 randomized controlled trials, 171 patients) were, MD=11.62, 95% CI: 9.78 to 13.46, P < 0.001. Our study mentioned a total of 14 cases of adverse reactions. One case was in control group, and the other 13 cases were in statins group which were all caused by atorvastatin. There were no serious adverse reactions in statins group and the rate of adverse reactions was 2.1%. The current evidence suggested that statins can improve cognitive function in patients with vascular cognitive impairment, with good safety. However, further conclusion still requests higher quality of randomized controlled trials.

Key words: cognitive impairment, dementia, vascular, randomized controlled trial, evidence-based medicine