Evaluation of the irritable bowel syndrome severity index in Japanese male patients with irritable bowel syndrome with diarrhea

BACKGROUND: Previous studies have indicated that ramosetron, a 5-hydroxytryptamine-3 receptor antagonist, achieves global improvement in irritable bowel syndrome (IBS) symptoms in male patients with IBS with diarrhea (IBS-D). However, in addition to global assessment it was deemed important to assess "clinically meaningful improvements, focusing on the patient's chief complaint and the severity of major IBS symptoms". We performed a randomized, placebo-controlled, phase IV pilot study to explore and examine efficacy variables that allow such evaluation of ramosetron in male patients with IBS-D. METHODS: = 51) once daily for 12 weeks. To evaluate "clinically meaningful improvements focusing on the severity of major IBS symptoms," the Japanese version of the IBS severity index (IBSSI-J) was used. The proportion of patients who had a ≥ 50% reduction in IBSSI-J overall score was 24/37 (64.9%) in the responder group on global assessment and 18/54 (33.3%) in the non-responder group at Week 12. CONCLUSIONS: Further examination will be needed before IBSSI-J can be used in clinical trials of agents for IBS-D. However, this study revealed that response on global assessment was correlated with improvement in the IBSSI-J, suggesting that global assessment reflects improvement of the symptom severity of patients with IBS-D. (Clinicaltrials.gov ID: NCT00918411 Registered 9 June 2009).