Psychometric validation of the Chinese version of the Short Inflammatory Bowel Disease Questionnaire and evaluation of its measurement invariance across sex

BACKGROUND: This study aimed to evaluate the psychometric properties of the Chinese version of the Short Inflammatory Bowel Disease Questionnaire (C-SIBDQ), and its measurement invariance across sex in Chinese patients with inflammatory bowel disease (IBD). METHODS: Between September 2018 and July 2021, 284 patients with IBD were recruited from a spleen and stomach clinic. All participants completed the C-SIBDQ, 12-item Short-Form Health Survey (SF-12), nine-item Patient Health Questionnaire Depression Scale (PHQ-9), and the seven-item Generalized Anxiety Disorder Scale (GAD-7). Floor and ceiling effects were evaluated by testing frequencies and composition ratios for the minimum and maximum C-SIBDQ scores. Exploratory and confirmatory factor analysis (CFA) were used to evaluate the C-SIBDQ’s factor structure and construct validity. Convergent validity was evaluated through examining bivariate correlations between the C-SIBDQ and the SF-12, PHQ-9, and GAD-7. Internal consistency reliability and retest reliability were evaluated by respectively calculating the Cronbach’s α and the intraclass correlation coefficient (ICC) among a subsample (n = 79) after 2 weeks. The measurement invariance across sex was evaluated through multiple-group CFA. RESULTS: The C-SIBDQ scores showed no floor or ceiling effects and had a single-factor structure and good convergent validity, with significant correlations with the SF-12, PHQ-9 and GAD-7. Good internal consistency (Cronbach’s α = 0.920) and test–retest reliability (ICC = 959) were observed. The C-SIBDQ also showed measurement invariance across sex, and females showed higher C-SIBDQ scores than males. CONCLUSIONS: The C-SIBDQ has high reliability, validity, and stability across sex, and can be used in clinics to assess the health-related quality of life of patients with IBD.