Introduction: Although constipation is a major complication of type 2 diabetes mellitus and chronic kidney disease, evidence for its treatment in these patients remains limited. This study aimed to evaluate the therapeutic efficacy of Bifidobacterium bifidum for constipation in these patients.
Materials and methods: In this multicenter, open-label, single-arm trial, 30 patients with type 2 diabetes mellitus and chronic kidney disease complicated by constipation were administered Bifidobacterium bifidum G9-1 for 12 weeks. The primary endpoint was the proportion of patients with normal stool form (Bristol Scale score ≥3.5 to <4.5). Secondary endpoints included stool form, defecation frequency, and quality of life.
Results: The proportion of patients with normal stool form at week 12 (44.8%; 13 patients) was significantly higher than that at baseline (3.3%; 1 patient; P = 0.002). The median Bristol score significantly increased from baseline by 0.6 at week 6 (P < 0.001) and 0.5 at week 12 (P < 0.001). Defecation frequency significantly increased by 0.2 ± 0.4 from baseline to week 6 (P = 0.026). The total constipation, abdominal pain, and indigestion scores on the Gastrointestinal Symptom Rating Scale significantly decreased. Abdominal symptoms, including straining, feelings of incomplete evacuation, bloating, and discomfort, significantly decreased. Glycated hemoglobin and the estimated glomerular filtration rate did not change significantly, whereas urinary albumin levels significantly decreased at week 6.
Discussion: Bifidobacterium bifidum improved stool form, defecation frequency, and quality of life of patients with type 2 diabetes mellitus and chronic kidney disease complicated by constipation, without worsening glycemic control and renal function.
Keywords: Constipation; Diabetic nephropathies; Probiotics.
© 2026 The Author(s). Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.