Determining the safety and effectiveness of Tai Chi: A critical overview of 210 systematic reviews of controlled clinical trials

Abstract

Background: This overview aims to critically appraise the best available systematic review (SR) evidence on the health effects of Tai Chi. Methods: Nine databases (English and Chinese languages) were searched for SRs of controlled clinical trials of Tai Chi interventions published between Jan-2010 and Dec-2020 in any language. Excluded were primary studies and meta-analyses that combined Tai Chi with other interventions. To minimise overlap, effect estimates were extracted from the most recent, comprehensive, highest quality SR for each population, condition, and outcome. SR quality was appraised using AMSTAR 2 and effect estimates with GRADE.Results: Of the 210 included SRs, 193 only included randomised controlled trials, one only included non-randomised studies of interventions, and 16 included both. The most common conditions were neurological (18.6%), falls/balance (14.7%), cardiovascular (14.7%), musculoskeletal (11.0%), cancer (7.1%) and diabetes mellitus (6.7%). Except for stroke, no evidence for disease prevention was found, instead proxy-outcomes/risks factors were evaluated. 114 effect estimates were extracted from 37 SRs (2 high quality, 6 moderate, 18 low, and 11 critically low), representing 59,306 adults. Compared to active and/or inactive controls, a clinically important benefit from Tai Chi was reported for 66 effect estimates; 53 reported an equivalent or marginal benefit, and 6 an equivalent risk of adverse events. Eight effect estimates (7.0%) were graded as high certainty evidence, 43 (37.7%) moderate, 36 (31.6%) low, and 27 (23.7%) very low. This was due to concerns with risk of bias in 92 (80.7%) effect estimates, imprecision in 43 (37.7%), inconsistency in 37 (32.5%) and publication bias in 3 (2.6%). SR quality was limited by the search strategies, language bias, inadequate consideration of clinical, methodological and statistical heterogeneity, poor reporting standards, and/or no registered protocol. Conclusions: The findings suggest Tai Chi has multisystem effects with physical, psychological, and quality of life benefits for a wide range of conditions, including individuals with multiple health problems. Clinically important benefits were most consistently reported for Parkinson’s disease, falls risk, knee osteoarthritis, low back pain, cardiovascular diseases including hypertension, and stroke. Notwithstanding, for most conditions, higher quality primary studies and SRs are required.