Wednesday, January 23, 2019

The effect of Tai Chi on four chronic conditions—cancer, osteoarthritis, heart failure and chronic obstructive pulmonary disease


Background Many middle-aged and older persons have more than one chronic condition. Thus, it is important to synthesise the effectiveness of interventions across several comorbidities. The aim of this systematic review was to summarise current evidence regarding the effectiveness of Tai Chi in individuals with four common chronic conditions—cancer, osteoarthritis (OA), heart failure (HF) and chronic obstructive pulmonary disease (COPD).
Methods 4 databases (MEDLINE, EMBASE, CINAHL and SPORTDiscus) were searched for original articles. Two reviewers independently screened the titles and abstracts and then conducted full-text reviews, quality assessment and finally data abstraction. 33 studies met the inclusion criteria. Meta-analyses were performed on disease-specific symptoms, physiological outcomes and physical performance of each chronic condition. Subgroup analyses on disease-specific symptoms were conducted by categorizing studies into subsets based on the type of comparison groups.
Results Meta-analyses showed that Tai Chi improved or showed a tendency to improve physical performance outcomes, including 6-min walking distance (6MWD) and knee extensor strength, in most or all four chronic conditions. Tai Chi also improved disease-specific symptoms of pain and stiffness in OA.
Conclusions The results demonstrated a favorable effect or tendency of Tai Chi to improve physical performance and showed that this type of exercise could be performed by individuals with different chronic conditions, including COPD, HF and OA.
The body of the research paper can be found at the doi link shown at the end. Omitted here for simplicity. We only show the discussion section here: 


The most important findings of this systematic review and meta-analyses on 33 studies and 1584 participants were that Tai Chi showed favorable effects or modest trends on improving 6MWD, knee extensor strength and quality of life in most or all four chronic conditions: cancer, OA, HF and COPD. Our findings support the results of a previous systematic review that showed the effectiveness of Tai Chi on health outcomes in older patients with chronic conditions.25 These findings also complement previous systematic reviews that only examined the effect of Tai Chi in a single chronic condition.59–62 Moreover, Tai Chi provided greater improvements than comparison groups in other physical performance measures including decreased TUG times and shorter sit-to-stand times in participants with OA. Finally, Tai Chi was more effective for improving pain and stiffness in OA compared with other interventions or controls.
Meta-analyses demonstrated that Tai Chi was more effective or showed modest trends compared with controls or other intervention groups towards improving the 6MWD in four chronic conditions. The 6MWD is a common primary outcome measure that is considered to evaluate functional exercise capacity.63 It shows moderate-to-high correlations with outcomes from peak cardiopulmonary exercise tests in participants with cardiac diseases64 and COPD63 and has also been shown to increase after resistance training in participants with chronic HF.65 The positive effect and trends of the 6MWD in all four conditions provide evidence that the exercise overload induced by Tai Chi was sufficient to improve functional exercise capacity in these chronic conditions.
Tai Chi improved the knee extensor muscle strength in participants with HF and COPD, but only showed a tendency towards improvement in participants with OA compared with other comparison groups and was not measured in participants with breast cancer. Although participants with knee OA have lower knee muscle strength,66 this impairment might be less than the weakness demonstrated in participants with HF67 and COPD,68 and thus a greater overload may be required than that provided by Tai Chi. Hence, Tai Chi appears to improve knee extensor strength in HF and COPD with more marginal benefits in OA. Further study is required to realise its impact on knee extensor strength in cancer survivors.
Other physical performance measures that require knee extensor strength improved more so after Tai Chi than other comparison groups in participants with OA. Most notably, TUG and sit-to-stand times showed greater improvements after Tai Chi than comparison groups in participants with OA. These findings may be attributed to the multifaceted training stimuli of Tai Chi that is directed towards improving balance and postural alignment in addition to strength.5 Although Tai Chi provides a minimal strength training stimulus, its positive influence on TUG and sit-to-stand times provides strong evidence of its clinical impact on important functional measures in participants with OA.
The effect of Tai Chi on quality of life within a particular condition was less consistent. The most positive effects of Tai Chi on quality of life were shown in participants with OA. This is somewhat similar to a systematic review that examined participants with OA that showed improved physical quality of life, but not quality of life related to mental health.69 The differing results can be explained by the small sample sizes in the previous systematic review, which only included two studies and 84 participants versus 181 respondents in our systematic review. A strong trend was shown in participants with COPD, and the inclusion of RCTs that were written in other languages may have resulted in a significant overall effect towards improving quality of life in participants with COPD similar to another systematic review.60
In addition to the improvement in physical performance measures, symptoms either improved or did not differ after Tai Chi compared with the other treatment or a control group. Pain and stiffness in OA showed greater improvements after Tai Chi and dyspnoea showed a trend towards improvement in participants with COPD. Improved pain and stiffness in participants with OA may be attributed to increases in muscle strength, balance and/or postural alignment.70 From a clinical perspective, this evidence provides some assurance to the health professional that prescription of Tai Chi to persons living with OA and COPD has the potential to improve functional exercise capacity, but not at the expense of aggravating pain or causing undue dyspnoea.

Limitations and strengths

This meta-analysis has some limitations. First, only studies published in English were included due to the lack of two reviewers who were fluent in other languages. Second, with the exception of OA, there were limited numbers of RCTs in the other chronic conditions, especially regarding the availability of raw data that could be included in the meta-analyses. Third, the sample sizes of included RCTs were quite small, contributing to limited power in most studies and in the aggregated data examined by meta-analyses. For example, the conflicting findings of the effect of Tai Chi on blood pressure in participants with HF are difficult to interpret because both reports had a small sample size.22 ,58 A fourth limitation is that participants in most studies represented patients who had one primary condition and may have excluded individuals with multimorbidity. Further study examining the effects of Tai Chi on multimorbidity is required to substantiate its benefits in this potentially complex patient group. Finally, the diversity of the type and parameters of Tai Chi in the included studies also limits the ability to make firm conclusions regarding the recommended Tai Chi exercise prescription for each chronic condition.
A key strength of this meta-analysis was the examination of the evidence regarding Tai Chi by reporting the symptoms, physiological and exercise outcomes of four common chronic conditions. Individuals with different chronic conditions may have different mechanisms that contribute to symptoms, impaired physical performance or quality of life. However, in people with multimorbidity, these underlying factors may also be inseparable or difficult to identify. Therefore, this systematic review offers a reasonable starting point to begin the quest for determining alternative exercise protocols, such as Tai Chi, for individuals who live with multimorbidity. Most of the included studies were moderate-to-high quality in terms of methodology (PEDro=4–7). Only one included study had poor quality32 and was excluded from quantitative syntheses due to missing data. This systematic review provided a quantitative synthesis of important physical performance outcomes, symptoms and quality of life. For some measures, evidence was limited due to the diverse outcome measurements among the conditions and small sample size. More rigorous RCTs with larger sample sizes are required to confirm the inconsistent findings among the included studies. Also, studies that examine patients with a broader range of diagnoses are required. For example, all of the studies examining cancer in this systematic review involved participants with breast cancer. It would be worthwhile to assess the effectiveness of Tai Chi on other types of cancer.
In conclusion, the results provided evidence regarding a favourable effect or tendency of Tai Chi on improving the performance of 6MWD, knee extensor strength and quality of life in people with cancer, OA, HF and COPD. Additionally, the meta-analyses showed the favorable effects of Tai Chi versus other interventions or no treatment on several disease-specific symptoms, including pain and stiffness. Taken together, Tai Chi demonstrates improvement in functional exercise capacity in individuals with different chronic conditions without aggravating symptoms of pain and dyspnoea. To summarize, Tai Chi appears to provide an adequate exercise stimulus and it could be a suitable exercise to prescribe for people with several co-morbidities that include COPD, HF and OA.

What are the findings?

  • Tai Chi can improve some physical performance outcomes in four chronic conditions (cancer, osteoarthritis, heart failure and chronic obstructive pulmonary disease) but not at the expense of worsening pain or dyspnoea.
  • Tai Chi may provide a suitable exercise stimulus for people with several co-morbidities.

How might this impact on clinical practice in the future?

  • It is possible to consider prescribing Tai Chi in people with multi-morbidity.
  • Tai Chi is an exercise that is suitable to improve physical performance in middle-aged and older adults.
  • Tai Chi can be a complementary therapy in some chronic conditions.
Chen YHunt MACampbell KL, et al. "
The effect of Tai Chi on four chronic conditions—cancer, osteoarthritis, heart failure and chronic obstructive pulmonary disease: a systematic review and meta-analyses"

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