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Journal Article


School of Chinese Medicine




Background: Alzheimer's disease (AD) is the most common type of dementia in the elderly. It is estimated that the global prevalence of dementia will rise from 24.3 million in 2005 to 81.1 million in 2040. AD has a devastating impact on sufferers, caregivers, their communities and the healthcare system in general. "Di-tan decoction" (DTD) is a traditional Chinese medicine (TCM) formula frequently used to treat symptoms that are now defined as AD in clinical treatment. However, the existing evidence for recommending DTD in clinical practice derives from studies that were methodologically flawed. In this study, we aim to determine the efficacy and safety of DTD in AD patients based on a rigidly randomized controlled trial. It will provide critical information on sample size and treatment regimen for conducting a full-scale clinical trial of DTD later. Methods/Design: This study will be a double-blind, randomized, placebo-controlled, add-on trial. After a 2-week run-in period, eligible patients with mild to moderate AD will be recruited and given either DTD or placebo twice daily for 24 weeks with follow-up 6 weeks after the last treatment. An increase of four points or greater on the scores of Alzheimer's Disease Assessment Scale-cognitive subscale (ADAD-cog) will be considered as a positive primary outcome. Total scores of the ADAD-cog, the Chinese version of Mini-Mental State Examination (C-MMSE), and the Chinese version of the Disability Assessment for Dementia (C-DAD) score will be used as secondary outcomes. Adverse events will also be reported. Discussion: This randomized trial will be the first rigorous empirical study on the efficacy of DTD for treating cognitive symptoms in AD patients. Its success will justify and warrant a large-scale clinical trial to further consolidate the evidence for DTD's efficacy in treating AD.


Alzheimer's disease, Chinese medicine, Di-Tan decoction, Randomized controlled trial

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BioMed Central

Peer Reviewed



© 2015 Chua et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.


This work is supported by an anonymous donation clinical research grant (GDS 0216), PuraPharm International (H.K.) Ltd. and Dr. Ho Tzu-leung’s Foundation. This study was also support by HMRF 12132091 from the Food and Health Bureau, Hong Kong Government, research grants (IRMS/12-13/1A, MPCF008-2014/2015) and Mr. & Mrs. Ko Chi Ming Centre for Parkinson’s Disease Research from Hong Kong Baptist University.



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