evaluation of treatment outcome measures in irritable bowel syndrome clinical trials

background: in clinical trials of irritable bowel syndrome (ibs), evaluation of treatment efficacy is still mainly subjective.we compared three outcome measures in reflecting response to treatment in a clinical trial of ibs. â  materials and methods: sixty three adult ibs patients participated in a placebo-controlled trial of 10-wk cognitive-behavioral therapy. patients completed the ibs-quality of life questionnaire (ibs-qol),ibs-symptom severity scale (ibs-sss), extra-intestinal symptom severity scale (eisss), and hospitalanxiety and depression scale (hads) before and after the intervention.after the intervention, patients responded to the ibs-adequate relied (ibs-ar) and ibs-global assessment of improvement (ibs-gai) instruments. patients were categorized into responders and non-responders based on each of the ibs-ar, ibs-gai, and ibs-sss instruments. quality of life, ibs and extra-intestinal symptoms severity, anxiety, and depression scores were compared between the responders and non-responders. results: forty six patients (mean age 31.5 â± 6.9 years, 82.6% female) completed the study. after the intervention, significant correlations were found between responder definitions results (r=0.385 to 0.689, p‹0.001). compared with ibs-ar and ibs-gai, defining responders based on the ibs-sss instrument was related to more reduction in severities of ibs and extra-intestinal symptoms, anxiety, and depression scores and to more increase in quality of life scores. conclusion: the ibs-sss instrument ismore comprehensive in reflecting changes in symptoms severity, quality of life, and psychological status compared with other outcome measures. ibs-ar is accepted as the current standard for evaluating the efficacy of ibs treatments, however, we recommend ibs-sss to be applied as well.