A Randomized Controlled Pilot Trial of Chinese Medicine (Di-Tan Decoction) in the Treatment of Alzheimer's Disease

Objective: This double-blind, randomized, placebo-controlled, add-on pilot study aimed at providing information for conducting a full-scale trial assessing “Di-tan decoction” (DTD), which is a traditional Chinese medicine (TCM) formula frequently used in TCM to treat symptoms that are now defined as Alzheimer’s disease (AD), in treating AD in the future. Methods: We randomly assigned 38 patients with AD to receive either DTD or placebo for 24 weeks. Primary outcome was changes in the total score of AD Assessment Scale-cognitive subscale (ADAS-cog) and secondary outcome was changes in the total score of Chinese version of the Disability Assessment for Dementia (C-DAD). Results: Although we observed some improvement in the total scores of ADAS-cog in the DTD group comparing to the placebo group, the changes were not statistically significant. The ADAS-cog sub-scores of the DTD group also showed non-significant trends of improvement in ideational praxis (p=0.100) and in comprehension (p=0.106) comparing to placebo group. Adverse events were mild and comparable between two groups. Conclusion: This is the first rigorous randomized control trial of DTD focusing on AD. At least five factors could explain the failure of the trends to be significant, namely length of trial, size of trial, stage of AD, palatability of the drug, and sensitivity of the scoring system. Given the limitation but with the safety and century’s use of DTD, a modified pilot study is needed to support the clinical effects of DTD. In conclusion, there is no evidence supporting the efficacy of DTD to act as a single treatment for AD.