Tai Chi for improving balance and reducing falls: An overview of 14 systematic reviews

Background:
Falls play a pivotal role in the cause of injury or death and have become a public health problem, especially for older people. Tai Chi may be an effective approach to improving balance and reducing falls. However, the conclusions of systematic reviews (SRs) have been inconsistent and the quality needs to be appraised critically.

Objective:
To provide an overview of the methodological quality, risk of bias and reporting quality as well as quality of evidence of SRs of Tai Chi for improving balance and reducing falls.

Methods:
We conducted a systematic search of English- and Chinese-language SRs in 8 electronic databases, from inception to October 2019. The methodological quality, risk of bias, reporting quality and the quality of evidence were independently assessed by 2 reviewers who used the A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2), Risk of Bias in Systematic reviews (ROBIS), the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Grades of Recommendations, Assessment, Development and Evaluation (GRADE). Primary outcomes were fall rate and the Berg Balance Scale score in older people and people with Parkinson disease. Secondary outcomes included these outcomes in stroke, osteoarthritis and heart failure.

Results:
A total of 14 relevant SRs were included: 13 were rated critically low quality and 1 was rated low quality by AMSTAR 2. By the ROBIS, all SRs were rated low risk in Phase 1 (assessing relevance) and Domain 1 of Phase 2 (study eligibility criteria). With regard to Domain 2, assessing the identification and selection of studies, 3 (21.4%) SRs were rated low risk. Eleven (71.4%) were rated low risk in Domain 3 (data collection and study appraisal), 11 (71.4%) were rated low risk in Domain 4 (synthesis and findings), and 9 (64.3%) were rated low risk in Phase 3 (risk of bias in the review). According to PRISMA, the reporting was relatively complete, but there were still some reporting flaws in the topic of protocol and registration (2/14, 14.3%), search strategy (5/14, 35.7%), risk of bias (6/14, 42.9%), additional analyses (6/14, 42.9%) and funding (4/14, 28.6%). Among the 14 SRs, Tai Chi had benefits for improving balance and reducing falls in older people and people with Parkinson disease; however, no definitive conclusions could be drawn for its effectiveness in stroke, osteoarthritis and heart failure. The level of evidence for fall rate was "moderate" to "high" for older people and "low" for those with Parkinson disease. The level of evidence of the Berg Balance Scale was "low" to "moderate" for older people and "low" for those with Parkinson disease. Among the downgraded factors, imprecision was the most common, followed by inconsistency and publication bias.

Conclusions:
Tai Chi may be beneficial for improving balance and reducing falls in older people and those with Parkinson disease. Because of limitations and inconsistent conclusions, further rigorous, normative and comprehensive SRs are needed to provide robust evidence for definitive conclusions.

Keywords: AMSTAR 2; Balance; Falls; GRADE; Overview; PRISMA; ROBIS; Tai Chi.

PMID: 31981834 DOI: 10.1016/j.rehab.2019.12.008