WHAT IS KNOWN AND OBJECTIVE: We evaluated the effectiveness of warning letters published by the pharmaceutical regulatory agency in Japan on communication of drug safety and risk by quantitative analysis of the national health insurance claims database (NHICD). We then explored what factors may have affected risk communication.
METHODS: We measured the implementation rate of the hepatitis virus-monitoring test among methotrexate (MTX)-treated patients; a warning letter had been issued regarding the use of MTX, as it apparently activates the hepatitis virus. Data from the NHICD, which include 99·3% of Japanese residents, were used. A total of 4 933 481 patients with rheumatoid arthritis (RA) (January-June, 2010) were the focus of this study.
RESULTS: The implementation rate of the hepatitis virus-monitoring test increased from 1·4% before to 1·8% after the warning letter announcement. Logistic regression analysis suggested that the installation of a drug information management room is one of the important factors affecting risk communication. Further analysis revealed that the hepatitis virus monitoring rates in hospitals without drug information management rooms increased from 2·3% to 4·1% due to the issue of the warning letter. WHAT IS NEW AND CONCLUSION: The warning letter from the regulatory agency plays an important role in risk communication in hospitals without drug information management rooms.