Effects of probiotic Bifidobacterium bifidum G9‐1 on the gastrointestinal symptoms of patients with type 2 diabetes mellitus treated with metformin: An open‐label, single‐arm, exploratory research trial

ABSTRACT Aims/Introduction Metformin is associated with the risk of gastrointestinal complications, and probiotic Bifidobacterium bifidum G9‐1 (BBG9‐1) can improve the symptoms of diarrhea. This study aimed to clarify the effects of probiotic BBG9‐1 on the gastrointestinal symptoms of type 2 diabetes mellitus patients using metformin. Materials and methods In this open‐label single‐arm exploratory study, 40 patients (mean age 64.0 ± 9.4 years) were given probiotic BBG9‐1 for 10 weeks. Changes in the gastrointestinal symptom rating scale total score, which was the primary end‐point, gastrointestinal symptom rating scale subscale scores, glycated hemoglobin levels and gut microbiota after the administration of probiotic BBG9‐1 were evaluated by the Student's t‐test. Results The gastrointestinal symptom rating scale total score significantly improved (from 2.02 ± 0.51 to 1.59 ± 0.43, change, −0.43 ± 0.49, P