Validation of the Mainland Chinese version of the Inflammatory Bowel Disease Questionnaire (IBDQ) for ulcerative colitis and Crohn's disease

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 for use in Mainland China. The aim of our study was to develop and validate the Mainland Chinese translation of the Inflammatory Bowel Disease Questionnaire for ulcerative colitis (UC) and Crohn's disease (CD) by assessing its construct validity, discriminant ability, reliability, and sensitivity to change. Methods: We administered a developed Mainland Chinese version of the Inflammatory Bowel Disease Questionnaire (IBDQ). Ninety-two Mainland Chinese patients (52 with UC and 40 with CD) completed the Mainland Chinese version of the IBDQ, the Chinese version of SF-36, and the global scale for general well-being. A subgroup of 71 patients also completed the Mainland Chinese version of the IBDQ and the global scales for general well-being on a second occasion. Clinical activity was assessed by the Walmsley and Harvey-Bradshaw simple indices. Results: The Mainland Chinese IBDQ scores correlated well with the related SF-36 dimensional scores for all 4 domains (r = 0.51-0.82), SF-36 total scores (r = 0.58-0.87), the colitis activity index (r = -0.56-0.74), and the CD activity index (r = -0.64-0.78) as well as with the global scales. The Mainland Chinese IBDQ was able to discriminate between active and inactive disease. Cronbach's a was 0.95 in UC and 0.94 in CD. Test-retest reliability was excellent (intraclass correlation coefficient 0.69-0.93) when it was repeated in patients whose clinical activity index was stable. In contrast, there was a significant difference between the baseline and follow-up measurements in patients whose clinical activity index was changed. Conclusions: The Mainland Chinese IBDQ proved to be a valid, discriminative, and reliable instrument for assessing health-related quality of life in patients with UC and CD in Mainland China.