408
Z. Zhou et al.
other sources (Fig. 1). A total of 292 articles remained
after removing duplicates. After removal of irrelevant
articles through titles and abstracts, full-text reading
of 50 articles was performed for further assessment.
Of these, 25 articles were excluded for various reasons
(see Fig. 1). Therefore, a final total of 23 studies
reported in 25 articles (32–56) were included in this
systematic review and meta-analysis.
Characteristics and risk of bias assessment in
individual study
One RCT reported in 3 articles (49–51) was regarded
as a study, which together with another study (48)
originated from Australia (Table II). One of 23 studies
originated from South Korea (43), one was conducted
in Thailand (42) and the rest in China. The sample size
ranged from 16 to 200, and mean age ranged from 35.6
to 69.5 years. The average duriation of disease a ranged
from 1 to 23 years, and the mean HbA1c before treat-
ment from 6.9% to 11.9%. Four studies (33, 34, 36, 38)
applied Chen style tai chi, and one (34) applied Yang
style tai chi. A simplified style was used in 5 studies
(45–47, 55, 56). Sun style and Yang style tai chi was
used in 2 studies (4 articles) (48–51), Lin style was
used in 1 study (42), and Da-yuan-jiang-tang style was
used in 1 study (54). The mean time per session ranged
from 15 to 120 min, mean intervention frequency from
2 to 14 sessions per week, and the mean duration of
the intervention from 4 to 24 weeks.
The majority of studies reported inclusion criteria,
except for 2 studies (38, 55). The treatment group and
the control group were comparable at baseline for all
studies, and point estimates and variability were all
reported. All studies except 4 (32, 36, 43, 56) were
considered high quality. The risk of bias assessment
is shown in Table III.
Effects of tai chi in patients with type 2 diabetes
Fasting plasma glucose. A total of 21 studies (32–45,
47, 51–56) evaluated the effects of tai chi on FPG. With
high heterogeneity across studies, a random-effects
pooled analysis was performed to synthesize the data.
The results indicated that tai chi was potentially effective
in reducing FPG (SMD –0.67; 95% CI –0.87 to –0.47;
p < 0.001; heterogeneity, I 2 = 53.2%, p = 0.001; Fig. 2).
Glycosylated haemoglobin (HbA1c). A total of 14
studies (35, 36–43, 45, 48, 49, 52–54) compared the
effects of tai chi on HbA1c with a control group. Meta-
analysis showed that tai chi was beneficial in lowe-
ring HbA1c (MD –0.88; 95% CI –1.45% to –0.31%;
p = 0.002; heterogeneity, I 2 = 97.8%, p < 0.001; Fig.
3A). Sensitivity analysis showed that 2 studies (37, 45)
exerted great influence on the stability of synthesized
results. The results after excluding these 2 studies also
indicated that tai chi was effective in decreasing HbA1c
(MD –0.53; 95% CI –0.62% to –0.44%; p < 0.001;
heterogeneity, I 2 = 43.4%, p = 0.033; Fig. 3B).
Literature retrieved from database searching (n=487):
Wan Fang (n=159), CNKI (n=98), CBM (n=39), VIP (n=86),
Pubmed (n=33), Embase (n=54), Cochrane Library (n=18)
Literature obtained from
other resources (n=0)
Literature after removing
duplicates (n=292)
Excluded articles (n=242):
Review (n=68);
Healthy individuals or patients with other
diseases (n=54);
Non-tai chi treatment (n=57);
Clinical guidelines (n=8);
Non-RCTs (n=26);
Pathological mechanism (n=29)
Articles assessed by reading
titles and abstracts (n=292)
Articles assessed through
full-text reading (n=50)
Excluded articles (n=25):
Reference paper (n=1);
Non-RCTs (n=1);
Non-T2DM participants (n=3);
Inappropriate control (n=13);
Non-targeted outcomes (n=5);
Unavailable data (n=2)
Studies (reported in 25 articles)
included in the systematic review
(n=23)
Fig. 1. Flow chart of study selection. T2MD: type 2 diabetes mellitus; RCT: randomized controlled trial.
www.medicaljournals.se/jrm