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

Abstract

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