Improving the quality of randomized controlled trials in Chinese herbal medicine, part I: clinical trial design and methodology.

Objective: To discuss the quality of randomized controlled trials (RCTs) in Chinese herbal medicine (CHM) with respect to design and methodology, and provide suggestions for further improvement in future clinical trials.

Methods: A search of the Cochrane Library was conducted to identify RCTs of CHM on line in July 2005. Quality of the RCTs was assessed using a 11-item checklist modified from the revised CONSORT statement, with 2 items specific to CHM (i.e. herb preparation form and quality control of herbs).

Results: The search yielded 167 RCTs that were selected for assessment. All trials included statements about the interventions, objectives, primary outcome design, statistical methods, and herb preparation form. Although 163 (97.6%) trials reported inclusion criteria, exclusion criteria were only reported in 26 (15.6%) trials. Fewer than 10% of trials clearly stated the random allocation sequence generation methods, and only 2.4% mentioned allocation concealment. The vast majority (86.8%) of trials were open-label, while only 13.2% used blinding. Almost half (45.5%) administered the CHM intervention as a tea or decoction. Only one trial (0.6%) reported a sample size calculation, and a single trial (0.6%) discussed quality control of the CHM intervention.

Conclusion: The overall methodologic quality of RCTs in CHM was poor. It is essential to improve the design of future RCTs in this clinical area.

Recommendations: (1) Investigator conducting RCTs should have formal training about clinical trial design; (2) A flow chart is recommended to ensure that all essential steps of clinical trial design are included. (3) Conducting pilot studies prior to RCTs may help improve their design; (4) Registration of clinical trials and publishing their protocols prior to enrollment may reduce publication bias and solicit peer reviews of the proposed design; (5) Collaboration between CHM investigators and traditional medicine academic research centers interested in integrative medicine may lead to quality improvement of RCTs of CHM.