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.