7 July 2006
Vincent Chung, Liang Liu, Zhaoxiang Bian, Zhongzhen Zhao, Wai Leuk Fong,
Wan Fung Kum, Jing Gao, Min Li
The objective of this study is to assess the efficacy and safety of
herbal medicines (HMs), as a monotherapy or adjunct therapy, compared to
placebo or conventional approaches in the treatment of idiopathic
Parkinson's disease (PD).
We conducted a systematic review of randomized
controlled trials from both conventional and alternative medicine
sources. Outcome measures were overall improvement, quality of life,
reduction of levodopa dose, and adverse events. Nine studies were
included, each testing a different HM. Six of the trials had limited
internal validity due to major flaws in design, including the lack of
proper randomization; insufficient blinding; unclear inclusive criteria
in terms of diagnostic criteria, baseline staging, and duration of
disease; lack of proper sample size calculation; and insufficient data
analysis. Imbalances in gender and ethnicity among the patients in the
included trials were observed.
No major adverse events emerged, and no
specific pattern was detected from the trials describing such data. In
addition to major methodological defects, heterogeneity in (1) HM
tested, (2) control treatment, and (3) outcome measure hindered in-depth
data analysis and synthesis.
Current evidence is insufficient to
evaluate the efficacy and safety of various HMs. Further studies with
improved trial design and reporting, with assessment on
cost-effectiveness, quality of life, and qualitative data are warranted.
