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

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