Clinical efficacy and safety of compound Congrong Yizhi Capsules on Alzheimer?s disease in mainland China: A systematic review with trial sequential analysis and GRADE assessment

Ethnopharmacological relevance: Alzheimer's disease (AD) is a degenerative disease of the central nervous system (CNS) with insidious onset. AD is also the most common cause of dementia. Compound Congrong Yizhi Capsules (CCYC), a traditional Chinese medicine compound developed by the team of Beijing University of Chinese Medicine, has been widely used to treat AD.Aim of this study: To systematically evaluate the clinical efficacy and safety of CCYC for AD by meta-analysis, Trial Sequential Analysis (TSA) and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system.Methods: This study was registered at PROSPERO (CRD42022295496). Randomized controlled trials (RCTs) of CCYC as the treatment for AD published before December 1, 2021 were retrieved from 4 Chinses databases, 4 English databases and 2 clinical trials registration systems. RevMan 5.4 and STATA 17.0 was used to conduct the meta-analysis of the included studies, the quality of outcomes was rated by the GRADE system, the TSA was conducted by TSA 0.9.5.10 software.Results: Seven studies were included, and the total sample size was 746. Meta-analysis showed that 6 months of treatment with CCYC plus conventional western medicine treatments (CTs) improved MMSE scores compared with CTs alone (WMD: 4.32, 95% CI: 3.23, 5.42), and TSA confirmed that more trials in the future will not reverse the result. Among which, CCYC combined with donepezil can significantly improve MMSE scores (WMD: 3.54, 95% CI: 2.86, 4.22). CCYC combined with olanzapine also showed good effect on both MMSE (WMD: 6.49, 95% CI: 5.54, 7.44) and ADL scores (WMD: 5.23, 95% CI: 4.63, 5.83). No serious adverse events were reported. The strengths of the evidences above are MODERATE.Conclusion: CCYC combined with cognition-modifying western medicine can improve cognitive function, mental behavioural symptoms, and activities of daily living in AD patients with good safety.