Background:

More and more Traditional Chinese medicines (TCM) are used to treat unstable angina pectoris (UAP) in China. There has been one protocol and one review about TCM for UAP according to the report from Cochrane Heart Group. Assessing the methodological quality is necessary to help reviewers and clinicians conducting Cochrane systematic reviews (CSR) and randomized controlled trials (RCTs) in this field in the future.

Objective:

to assess the methodological quality of RCTs about Chinese medicinal herbs for UAP in China.

Methods:

89 journals of Chinese medicine were hand searched. All the journals were searched until the latest issue of 2004.The earliest journal was from 1977. 4 Chinese databases were electronic searched (CMCC, CMBDISK, CJFD and VIP). Two reviewers read and analyzed all of the included trials independently (Kappa=0.93).

Results:

175 RCTs were included. Sample size in every RCT was small(varied from 25 to 120).
1. All trials were described as randomized but the method of randomization were well described in only 13 trials (7.43%). The rest trials didn’t mention the definite randomization method (92.57%);
2. Inclusion criteria were reported in 169 trials (96.57%) while exclusion criteria were reported in only 46 trials (26.28%);
3. None of the trials reported allocation concealment;
4. None of the trials gave a description of withdrawals and dropouts. No intention-to-treat was reported;
5. only 5 trials performed blinding (2.86%) and they were single-blinded.

Conclusion:

When we used Cochrane approach to assessment of allocation concealment and Jadad score to assess the quality of the trials, Grade C and 1 point should be given to 162 RCTs(92.57%).The rest 13 RCTs should fall into Grade C and 2 points. Considering very small sample size and poor methodological quality, making conclusion of CSRs based on those RCTs should be much more cautious. Because of various bias, results are not likely to be valid and credible. It is also suggested that clinicians in China should pay more attention to the clinical epidemiology. Only when good evidence was produced, can the CSR make contribution to the application of TCM for UAP in the world.