Abstract
BACKGROUND: Bowel stool and/or gas distribution is an important indicator of bowel function. The mean colonic transverse diameter of the colon and rectum (constipation index) is a stool and/or gas distribution parameter assessed via transabdominal ultrasonography and an indirect indicator of colonic transit time. Elobixibat, an ileal bile acid transporter inhibitor, increases the number of bowel movements in chronic constipation (CC) patients. AIMS: To determine whether the constipation index changes following treatment with elobixibat and evaluate the relationship between changes in the constipation index and fecal bile acid concentration. METHODS: We conducted a prospective, randomized, double-blind, placebo-controlled trial in 17 CC patients aged ≥ 60 years who were administered elobixibat or placebo daily for 1 week. Changes in stool and/or gas distribution and stool bile acid concentrations were analyzed before and after treatment. RESULTS: Elobixibat, but not placebo, significantly reduced the constipation index. A significant negative correlation was found between the change in the constipation index and the change in total fecal bile acid concentration. CONCLUSION: Elobixibat increases the total fecal bile acid concentration of CC patients, which results in shortened colonic transit time. Trial Registration: JRCT ID: jRCTs061200030; https://rctportal.niph.go.jp/en/detail?trial_id=jRCTs061200030.