Can Tianqi capsule, a Chinese herbal medicine formula, prevent type 2 diabetes among patients with impaired glucose tolerance?
Date of publication of the randomized controlled trial: February 2014
Design
Randomized controlled trial (RCT).
Participants
420 patients (mean age: 52.4 years, male %: 48.6%) who had impaired glucose tolerance (IGT) defined as having 2-hour plasma glucose concentration of 7.8-11.1 mmol/L after a 75g oral glucose tolerance test (OGTT) and fasting plasma glucose greater than 7.0 mmol/L.
Intervention
5 Tianqi capsules (1.6g) administered 3 times per day for 12 months. The formula is consist of 10 Chinese herbal medicines: Astragali Radix, Coptidis Rhizoma, Trichosanthis Radix, Ligustri Lucidi Fructus, Dendrobii Caulis, Ginseng Radix, Lycii Cortex, Ecliptae Herba, Galla Chinensis, and Corni Fructus.
Comparator
Comparison: Tianqi capsules versus placebo.
Major Outcomes
Outcome 1: Conversion rate of IGT to type 2 diabetes;
Outcome 2: Rate of restoring normal glucose tolerance.
Settings
This trial was performed in an outpatient setting.
Comparison    Tianqi capsules versus placebo
Main Results
Compared to placebo, IGT patients who were assigned with Tianqi capsules had significantly lower rate of conversion from IGT to type 2 diabetes (p=0.01). They also had significantly higher rate of restoring normal glucose tolerance (p=0.001) compared to placebo.
Comparison: Tianqi capsules versus placebo among patients with impaired glucose tolerance
Outcomes No. of studies (Total number of participants) Rate (%)/ No. of participants Heterogeneity test ( I2) p value Overall quality of evidence*
Intervention Comparator
1 1 (420) 18.2/ 210 29.3/ 210 Not applicable as there is only 1 study. 0.01 Moderate
2 1 (420) 63.1/ 210 46.6/ 210 Not applicable as there is only 1 study. 0.001 Moderate
Comparison    Tianqi capsules versus placebo
Main Results
Compared to placebo, IGT patients who were assigned with Tianqi capsules had significantly lower rate of conversion from IGT to type 2 diabetes (p=0.01). They also had significantly higher rate of restoring normal glucose tolerance (p=0.001) compared to placebo.
Comparison: Tianqi capsules versus placebo among patients with impaired glucose tolerance
Outcomes 1 2
No. of studies (Total number of participants) 1 (420) 1 (420)
Rate (%)/ No. of participants Intervention 18.2/ 210 63.1/ 210
Comparator 29.3/ 210 46.6/ 210
p value 0.01 0.001
Overall quality of evidence* Moderate Moderate
Conclusion
Benefits
Compared to placebo, Tianqi capsules is significantly more effective in lowering the conversion rate of IGT to type 2 diabetes and increasing the restoration rate of IGT to normal glucose tolerance among IGT patients. For Outcome 1-2, the overall quality of evidence is moderate. Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
Harms
Gastrointestinal reactions, such as nausea, flatulence, constipation and diarrhea were the most common adverse reaction. No severe adverse events occurred in the trial.
Link to Original Article
https://www.ncbi.nlm.nih.gov/pubmed/24432995
The synopsis is based on the following article:
Lian F, Li G, Chen X, Wang X, Piao C, Wang J, et al. Chinese herbal medicine Tianqi reduces progression from impaired glucose tolerance to diabetes: a double-blind, randomized, placebo-controlled, multicenter trial. The Journal of Clinical Endocrinology & Metabolism. 2014 Feb;99(2):648-55.


* Interpretation of quality assessment results:
• Very low: Further research is most likely to have an important impact on our confidence in this estimate of effect.
• Low: Further research is likely to have an important impact on our confidence in this estimate of effect.
• Moderate: Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
• High: Further research is unlikely to have an important impact on our confidence in this estimate of effect.
• Very high: Further research is most unlikely to have an important impact on our confidence in this estimate of effect.

Details of assessment method can be found at Chung VC, Wu XY, Ziea ET, Ng BF, Wong SY, Wu JC. Assessing internal validity of clinical evidence on effectiveness of CHinese and integrative medicine: Proposed framework for a CHinese and Integrative Medicine Evidence RAting System (CHIMERAS). European Journal of Integrative Medicine. 2015 Aug 31;7(4):332-41.