Can Chinese Herbal Medicine Adjunctive Therapy Improve Outcomes of Senile Vascular Dementia? Systematic Review with Meta-analysis of Clinical Trials

Many publications have reported the growing application of complementary and alternative medicine, particularly the use of Chinese herbal medicine (CHM) in combination with routine pharmacotherapy (RP) for senile vascular dementia (SVD), but its efficacy remains largely unexplored. The purpose of this study is to evaluate the efficacy of CHM adjunctive therapy (CHMAT), which is CHM combined with RP, in the treatment of SVD. Publications in seven electronic databases were searched extensively, and 27 trials with a total of 1961 patients were included for analysis. Compared with RP alone, CHMAT significantly increased the effective rate [odds ratio (OR) 2.98, 95% confidence interval (CI) 2.30, 3.86]. In addition, CHMAT showed benefits in detailed subgroups of the Mini-Mental State Exam (MMSE) score from time of onset to 4 weeks (WMD 3.01, 95% CI 2.15, 3.87), 8 weeks (weighted mean difference (WMD) 2.30, 95% CI 1.28, 3.32), 12 weeks (WMD 2.93, 95% CI 2.17, 3.69), and 24 weeks (WMD 3.25, 95% CI 2.61, 3.88), and in the activity of daily living scale score from time of onset to 4 weeks (WMD -4.64, 95% CI -6.12, -3.17), 8 weeks (WMD -4.30, 95% CI -6.04, -2.56), 12 weeks (WMD -3.89, 95% CI -4.68, -3.09), and 24 weeks (WMD -4.04, 95% CI -6.51, -1.57). Moreover, CHMAT had positive effects on changes in the Hasegawa dementia scale, National Institutes of Health Stroke Scale, Clinical Dementia Rating, and Montreal Cognitive Assessment scores, as well as blood fat levels (total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and apolipoprotein E), platelet aggregation rate (1-min platelet aggregation rate, 5-min platelet aggregation rate, and maximal platelet aggregation rate), and blood rheology (whole-blood viscosity and hematocrit). No serious or frequently occurring adverse effects were reported. Weaknesses of methodological quality in most trials were assessed using the Cochrane risk of bias tool, while the quality level of Grades of Recommendations Assessment Development and Evaluation (GRADE) evidence classification indicated 'very low'. This systematic review suggests that CHM as an adjunctive therapy can improve cognitive impairment and enhance immediate response and quality of life in SVD patients. However, because of limitations of methodological quality in the included studies, further research of rigorous design is needed.