Efficacy of Bifidobacterium bifidum G9-1 in improving quality of life in patients with chronic constipation: a prospective intervention study.

Chronic constipation is a functional disorder that decreases a 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 patients with constipation. This was a prospective, single-center, non-blinded, single-arm feasibility trial. A total of 31 patients with constipation and decreased QOL received BBG9-1 treatment for 8 weeks, followed by a 2-week washout period. The primary endpoint was change in the overall Japanese version of the patient assessment of constipation of QOL (JPAC-QOL) score after probiotic administration relative to that at baseline. Secondary endpoints included changes in gut microbiota, stool consistency, frequency of bowel movement, degree of straining, sensation of incomplete evacuation, and frequency of rescue drug use. The overall JPAC-QOL scores and frequency of bowel movement significantly improved after BBG9-1 administration from those at baseline (p<0.01 and p<0.01, respectively). There were no statistically significant changes in other clinical symptoms. Subset analysis revealed that patients with initial Bristol Stool Form Scale stool types of <4 had improvements in stool consistency, a significant increase in the frequency of bowel movements, and a significant alleviation in the degree of straining, following BBG9-1 administration. At the genus and species levels, Sarcina and Sarcina maxima were significantly increased. Functional analysis showed that butanoate metabolism increased significantly, whereas methane metabolism decreased significantly. We concluded that BBG9-1 is safe and improves QOL in patients with constipation. The underlying improvements may be due to changes in stool consistency.