ABSTRACT
The Japan Society for Oriental Medicine has summarized randomized controlled trials (RCTs) using Japanese traditional (Kampo) medicine in structured abstracts, named “Evidence Reports of Kampo Treatment” (EKAT). In this study, we developed a method of classification based on study design, method of intervention, study aim, journal credibility, and year of publication. Then we classified 416 RCTs in EKAT and examined the current status and evolution of RCTs using Kampo medicine in Japan. Double-blinded RCTs (DB-RCTs) accounted for only 8.9% of the RCTs in EKAT, and 86.5% of DB-RCTs were placebo-controlled. Among the RCTs that aimed to investigate the efficacy of Kampo medicine for diseases without standard Western medical treatment, DB-RCT accounted for 64.9%. In recent years, there have been fewer envelope RCTs and quasi-RCTs, which are prone to an increased risk of bias. The proportion of articles reporting RCTs in journals with an impact factor ( > 0.79 points reported by Journal Citation Reports) has been increasing with each passing year. This implies that the recent research in Kampo medicine has improved its quality and has gained an appreciation in modern medicine. The present study was conducted in “Problem-based Learning” in the 2nd grade of Tohoku University School of Medicine.