Danggui-Shaoyao-San for dementia: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND: Although memory loss and other symptoms of dementia pose tremendous burdens on patients and societies, there is currently no cure for dementia. METHODS: We conducted a systematic review and meta-analysis of the anti-dementia effects of Danggui-Shaoyao-San (DSS), which is derived from natural resources. We searched for randomized controlled trials (RCTs) from inception to June 2019. We searched PubMed, Embase, Korean databases (Research Information Service System and Oriental Medicine Advanced Searching Integrated System), Chinese databases (China Knowledge Resource Integrated Database and Wanfang Database), and Japanese databases (CiNii and J-STAGE). Studies were included if they were a RCT, investigated the efficacy of DSS or its modified form, and included participants with dementia. Use of DSS with other treatment (eg, acupuncture, anti-dementia drugs, etc) was included. Items of each trial were evaluated by 2 independent reviewers. Data were pooled by using random-effect models. RESULTS: A total of 482 studies were identified, and 5 eligible studies for Alzheimer disease (AD) and 4 studies for vascular dementia (VD) were included in the final analysis, representing a total of 567 participants. As for AD, pooled results of the Mini-Mental State Examination (MMSE) (mean differences [MD] 4.60; 95% confidence interval [CI] 4.29, 4.91) and activities of daily living (MD 11.40; 95% CI 10.94, 11.86) favored DSS. DSS had synergistic effect with acupuncture over acupuncture alone in MMSE (MD 1.69; 95% CI 1.05, 2.34), Hasegawa Dementia Scale (MD.62; 95% CI –0.20, 1.44), and activities of daily living (MD 2.38; 95% CI 1.92, 2.85). In VD, pooled results showed a significant difference in the score of dementia scales such as MMSE and Hasegawa Dementia Scale compared with nootropic drugs. DSS significantly reduced symptoms (odds ratio 5.02, 95%, CI 2.76–9.11) in patients with VD. The respective size of each RCTs was small and some included studies were of low quality due to their limited description on methodological issues. CONCLUSION: These estimates suggest that DSS provides clinically important reductions in symptoms of AD and VD and can be a promising anti-dementia drug candidate.