In Japan, there is no national surveillance study of Clostridioides (Clostridium) difficile infection (CDI), and details about the epidemiology and treatment status of CDI are unknown. Additionally, clinical practice guidelines (CPGs) for CDI are published by four different institutions. All CPGs recommend that the antimicrobials, vancomycin (VCM) and metronidazole (MNZ), should be selected according to disease severity. However, the trends for VCM and MNZ use in Japan remain unclear. Therefore, this study was aimed at clarifying the secular trends for VCM and MNZ use based on sales data from 2006 to 2015 and discussing its impact on CDI status and drug costs. This is the first study to clarify the antibiotic use trends for CDI treatment. We found that the total use increased over time (r = 0.0013, Pfor trend < 0.0001). While VCM use significantly decreased (r = -0.0003, Pfor trend = 0.0002), MNZ use increased (r = 0.0017, Pfor trend < 0.0001). These results show that although treatment for CDI was in line with CPGs, CDI incidence might be on an increasing trend. Additionally, despite the increased total use, the total drug costs decreased by 55% ($ 25 million) from 2006 to 2015. It was also surmised that CDI treatment in compliance with CPGs would lead to a reduction in drug costs. Hence, to understand the epidemiology of CDI, it is important to continuously investigate the use of drugs used for CDI therapy.
Keywords: Clostridioides difficile; Clostridioides difficile infection; metronidazole; vancomycin.