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

We have developed a measure of subjective health status (quality of life) for patients with inflammatory bowel disease (IBD). Ninety-seven patients with IBD described problems they had experienced as a result of the disease; the 32 most frequent and important items were included in the Inflammatory Bowel Disease Questionnaire (IBDQ). Sixty-one IBD patients were evaluated twice. One month separated the evaluations, at which disease activity indices, the IBDQ, and a number of other questionnaires were administered. Reproducibility studies in 19 stable patients showed improvement in scores, but also a small within-person standard deviation. Responsiveness studies revealed large changes in scores in patients who had improved or deteriorated and suggested that the IBDQ was more responsive than a general health status measure. Responsiveness appeared greater in patients with ulcerative colitis than in those with Crohn's disease. Predicted and observed correlations between changes in IBDQ score and changes in other measures were similar. We conclude that although further testing is required, particularly in examining the relation between changes in the IBDQ and changes in the activity of Crohn's disease, the IBDQ shows promise as a measure of health status for clinical trials in IBD.