Reliability, validity, and responsiveness of the Japanese version of the inflammatory bowel disease questionnaire

Background. Inflammatory bowel disease affects the quality of a patient's life in many ways, but no validated instrument for measuring disease-specific quality of life in these patients is available in Japan. We developed a Japanese version of the Inflammatory Bowel Disease Questionnaire (IBDQ), together with the author of the original English-language version. Methods. Translation and cross-cultural adaptation followed an accepted process. The reliability, validity, and responsiveness of the IBDQ's four subscales were then assessed in a prospective cohort of Crohn's disease patients who underwent hospitalization. Results. Internal consistency was acceptable for all four subscales. Concurrent validity (with the Short Form [SF]36 as a reference) was as expected. Scores on the IBDQ could be used to discriminate patient subgroups with different levels of disease activity. Responsiveness was comparable to that of the SF36. Conclusions. This Japanese version of the IBDQ is reliable, valid, and responsive for assessing disease-specific quality of life in patients with Crohn's disease.