Quality of life: A valid and reliable measure of therapeutic efficacy in the treatment of inflammatory bowel disease

BACKGROUND/AIMS: Quality of life (QOL), a subjective index of health perception and function, embraces physical, social, and emotional performance but has not had a prominent role in clinical trials of inflammatory bowel disease (IBD). To test the robustness of the Inflammatory Bowel Disease Questionnaire (IBDQ), a disease-specific QOL index, this study assessed its validity, reliability, and responsiveness during a multicenter trial. METHODS: Three hundred five patients with stable Crohn's disease received cyclosporin or placebo for 18 months. IBDQ and dimensional scores (bowel, social, systemic, and emotional) were correlated with disease activity (Crohn's disease activity index [CDAI] and Harvey-Bradshaw index). Concordance of IBDQ scores was tested in 280 stable subjects. Linear regression evaluated change in IBDQ scores over time. RESULTS: IBDQ scores correlated highly with CDAI (r = -0.67; P < 0.0001). The reliability coefficient for IBDQ score was 0.70 vs. 0.66 for CDAI and 0.55 for Harvey-Bradshaw index. Regression line slopes of IBDQ scores were significantly different in patients who deteriorated from those who remained stable ([b] < 0.15; P < 0.0001). QOL scores were lower in patients who required surgery. CONCLUSIONS: The IBDQ is a valid reliable assessment tool that reflects important changes in the health status of patients with IBD. The IBDQ is a robust measure of therapeutic efficacy and should be used in future clinical trials in IBD.