BACKGROUND: Glucagon-like peptide-1 receptor agonists, such as liraglutide, reduce hyperglycaemia and induce weight loss and are used as a treatment in diabetes. However, common adverse effects include nausea, loss of appetite and prolonged gastric emptying. It is not known whether these changes are centrally generated or if liraglutide alters the enteric motility.

OBJECTIVE: To investigate the effects of liraglutide on gastrointestinal function and symptoms.

METHODS: A total of 48 adults with type 1 diabetes and confirmed distal symmetric polyneuropathy were randomised to receive liraglutide 1.8 mg/day or placebo for 26 weeks. Regional transit times and motility indexes were assessed with a wireless motility capsule, whereas symptoms were evaluated using the validated gastroparesis cardinal symptom index.

RESULTS: Liraglutide treatment reduced large bowel transit time (31.7%, p = 0.04) and decreased motility index (6.1%, p = 0.04) compared to placebo, whereas the groups did not differ in gastric emptying or small-bowel transit times. Liraglutide increased postprandial fullness with 29% (p = 0.01). Increased small bowel transit time was associated with decreased bloating (p = 0.008).

CONCLUSION: Liraglutide accelerates large bowel transit and decreases motility index, which may indicate better coordination of propulsive motility. This potentially improves the function of the enteric nervous system, leading to normalised colonic function and positive effects in type 1 diabetes.