Kampo (Japanese herbal) medicines are often used in clinical practice in Japan. However, it is unclear how Kampo medicines are quoted and evaluated in current clinical practice guidelines (CPGs). Here, we systematically reviewed Japanese CPGs, and aimed to reveal how Kampo medicines are described in the CPGs.
We reviewed the quasi-comprehensive list of Japanese CPGs available from the Toho University Medical Media Center (TUMMC) having the largest data base on Japanese CPGs, and also used a hand search. CPGs containing Kampo products were classified into three types based on how Kampo was handled. CPGs that provided recommendations based on evidence were classified as "type A". Those which cited references but did not provide any recommendations were classified as "type B". Those which described the Kampo practice or Kampo-related terms without providing any relevant references were classified as "type C".
By the end of March of 2007, 35 (10.1%) of 346 CPGs listed by TUMMC contained descriptions of Kampo products. We discovered one Kampo-related CPGs in a hand search process. Of these 36 CPGs, 6 were "type A", 13 were "type B", and 17 were "type C". Although results from pertinent randomized controlled trials (RCTs) were available, we noticed that some well-known RCTs studying Kampo medicines are missing in corresponding CPGs.
We revealed that the citation rate of Kampo medicines in CPGs was approximately 10% and that some pivotal trials for Kampo medicines were not quoted in CPGs. Kampo medicines in CPGs should be assessed more comprehensively and scientifically.