The Sweet Side of Constipation: Colonic Motor Dysfunction in Diabetes Mellitus

Background/Objectives: Chronic constipation is a prevalent gastrointestinal (GI) disorder among individuals with diabetes mellitus (DM), occurring more often than in healthy subjects. This review provides a systematic overview of this often-underestimated clinical condition in people with DM. Methods: A narrative review of literature up to 30 May 2025 was conducted, focusing on studies regarding the pathogenesis of constipation in DM, the correlation with GLP-1 RAs treatment, and the diagnostic-therapeutic framework. Results: The mechanisms underlying constipation in DM remain largely unclear; however, a multifactorial etiology has been proposed, involving structural changes in various tissues within the GI tract wall, as well as functional abnormalities, often secondary to hyperglycemia. It is noteworthy that the use of GLP-1 RAs, a class of medications crucial for managing glycemic control and reducing cardiovascular and renal risk in type 2 DM, is another cause of constipation. The diagnosis of constipation is typically based on clinical evaluation, as validated methods for assessing colonic transit are invasive and available only in specialized centers. Treatment objectives include alleviating symptoms and restoring bowel function. The primary strategy for management involves dietary changes and physical activity. If the clinical response is inadequate, the use of laxatives is recommended. Finally, newer agents and mechanical methods may be considered for scenarios that are particularly severe. Conclusions: Given the increasing global prevalence of DM, healthcare professionals must recognize the clinical problem constituted by the occurrence of chronic constipation, especially considering the use of medications such as GLP-1 RAs that may induce this clinical condition.