The efficacy of Bifidobacterium bifidum G9-1 in improving quality of life in patients with chronic constipation

Abstract Background: Chronic constipation is a functional disorder that decreases patient’s quality of life (QOL). Because dysbiosis has been associated with constipation, we aimed to investigate the efficacy of Bifidobacterium bifidum G9-1 (BBG9-1) in improving QOL in constipated patients. Methods: This was a prospective, single-center, non-blinded, single-arm, feasibility trial. A total of 31 patients received BBG9-1 treatment for 8 weeks, followed by a 2-week washout period. The primary endpoint was the change in the overall Patient Assessment of Constipation of QOL (PAC-QOL) score relative to that at the baseline after probiotic administration. Secondary endpoints included changes in intestinal flora, stool consistency, frequency of bowel movement, degree of straining, sensation of incomplete evacuation, and frequency of rescue drug use. Results: The overall PAC-QOL scores and frequency of bowel movement were significantly improved after BBG9-1 administration compared to those at baseline (p < 0.05, p < 0.05, respectively). There were no statistically significant changes in other clinical symptoms. Subset analysis revealed that patients with the initial Bristol Stool Form Scale of < 4 had improvements in stool consistency, a significant increase in the frequency of their bowel movements, and a significant alleviation in their degree of straining following BBG9-1 administration. Sarcina at the genus level and Sarcina maxima at the species level were significantly increased. Functional analysis showed that butanoate metabolism increased significantly, whereas methane metabolism decreased significantly. Conclusions: BBG9-1 is safe and improves the QOL of constipated patients. The underlying improvements may be due to changes in stool consistency. Trial registration: UMIN 000029969. Registered 15 November 2017, https://www.umin.ac.jp/