Exenatide Delays Gastric Emptying in Patients with Type 2 Diabetes Mellitus but not in Those with Gastroparetic Conditions

The effect of the treatment with glucagon-like peptide (GLP)-1 receptor agonists on gastric emptying in patients with diabetes with and without gastroparesis is analysed. Patients with type 2 diabetes mellitus subjected to GLP-1 receptor agonist therapy with exenatide were examined before and shortly after initiation of treatment. Gastric half-emptying time was determined by 13C-octanoic breath test; routine laboratory parameter as well as active GLP-1, ghrelin, leptin, insulin, proinsulin and C-peptide levels were determined in fasting state as well as postprandial secretion within 1 h after a standardised meal. Thirty patients' data sets were available for evaluation, of those 20 patients had no gastroparesis and 10 patients showed pathological results following the breath test. Gastric half-emptying time was prolonged in nearly all patients who presented without gastroparesis at initiation of treatment with GLP-1 receptor agonists, only 2 patients with pre-existing mild gastroparesis had worsening of gastric emptying. No effect was detected on leptin and ghrelin levels. Postprandial GLP-1 concentrations measured as AUC after meal decreased significantly. Fasting insulin and C-peptide levels increased significantly without effect on postprandial levels. Proinsulin levels - fasting as well as AUC - decreased non-significantly. Patients reported comparable perception of therapeutic effects. Treatment with GLP-1 receptor agonists may be applied in patients with pre-existing gastroparesis; no effect in terms of worsening of symptoms compared to those without gastroparesis was detected. Patients reported outcome was independent from underlying gastroparesis. Negative effects on gastric emptying were only detected in patients without or with mild gastroparesis.