Supplementary Material for: Bifidobacterium bifidum G9-1 and Quality of Life in Chronic Constipation: A Multicenter, Double-blind, Randomized Controlled Trial

Introduction: Patients with constipation often experience impaired quality of life (QOL). A previous open-label study of Bifidobacterium bifidum G9-1 (BBG9-1) in patients with chronic constipation reported a significant improvement in defecation-related QOL. Thus, we conducted a multicenter, randomized controlled study to assess the efficacy of BBG9-1 in patients with chronic constipation. Methods: Patients diagnosed with or being treated for chronic constipation between July 2020 and January 2022 and having an overall score of ≥1 on the Japanese version of the patient assessment of constipation quality of life scale (JPAC-QOL) were included. Following a 2-week baseline period, BBG9-1 or placebo was administered for 8 consecutive weeks. The primary endpoint was the change in the JPAC-QOL overall score pre-administration and 8 weeks post-administration of BBG9-1; secondary endpoints were changes in JPAC-QOL subscale scores, number of days of defecation, stool consistency, straining during defecation, and feeling of incomplete evacuation after defecation pre-administration and 8 weeks post-administration. Results: Data from 140 patients (83 women) were analyzed. The JPAC-QOL overall score improved by 0.65±0.56 in the treatment group and 0.54±0.67 in the placebo group, with no significant difference (P=0.282). However, the physical discomfort subscale showed a nominally significant improvement in the treatment group (P=0.041). Stratified analysis revealed increased defecation frequency and reduced straining in those with high baseline straining scores. No adverse events were reported. Conclusion: BBG9-1 administration reduced physical discomfort but did not significantly improve the JPAC-QOL overall score, indicating its limited effect on chronic constipation.