This overview was aimed at critically appraising the best available systematic review (SR) evidence on the health
effects of Tai Chi. 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 minimize 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.
Of the 210 included SRs, 193 only included randomized controlled trials, one only included non-randomized
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 had 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.
The authors concluded that 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.
The authors start the discussion section by stating: This critical overview comprehensively identified SRs of Tai Chi published in English, Chinese and Korean languages that evaluated the effectiveness and safety of Tai Chi for health promotion, and disease prevention and management.
I must say that I do not find the overview all that ,critical’. The authors admit that the primary studies often lacked scientific rigor. Yet they draw firm positive conclusions from the data. I think that this is wrong.
Most of the authors of this overview come from Chinese institutions dedicated to promoting TCM. Yet there is no declaration that this fact might constitute a conflict of interest.
I also miss critical comments on two important questions:
- Are the positive effects of Tai chi superior to conventional treatments of the respective conditions?
- Are the effects of Tai chi really due to the treatment per see or might they be largely caused by context effects (which, considering the nature of the therapy, might be substantial)?