Tai Chi and Parkinson’s disease (PD): A systematic overview of the scientific quality of the past systematic reviews

The aim of the current study was to assess the scientific quality of the past systematic reviews regarding the application of Tai Chi in the management of Parkinson’s disease (PD) using a systematic overview. The search of PubMed and PsycInfo in February 2018 identified k=10 relevant systematic reviews published in 2008–2017 with terms PD, Tai Chi, and review in titles or abstracts. The quality of reviews was assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR2) and the quality of meta-analytic procedures was assessed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The k=10 systematic reviews assessed various outcomes of Tai Chi in PD using a qualitative (k = 4) or a quantitative synthesis (meta-analysis; k = 6) of data from up to 14 primary studies published in English. The review strengths were the comprehensive search for literature, data coding, and data quality assessment. The review limitations were the high overlap in the primary data and the lack of either the review protocol, the list of excluded studies or the conflict of interest statement in the primary studies. The critical problems were that the qualitative data synthesis relied on the statistical significance of results in the primary studies with small sample sizes and that the computational details of meta-analysis were inadequately reported. The past systematic reviews suggest that Tai Chi is a promising complementary treatment for PD. However, the quality of such past reviews is limited. Future systematic reviews can be improved by adequately reporting the methodological details and adhering to the guidelines for conducting such reviews. The clinical relevance of Tai Chi in terms of the magnitude and the longer-term durability of its outcomes should be tested in future RCTs with larger sample sizes.