Gastric emptying in diabetic patients by the ¹³C-octanoic acid breath test: Role of insulin in gastric motility

Background: Impairment of gastric emptying is well recognized in patients with diabetes mellitus (DM), especially long-standing insulin-dependent diabetes mellitus (IDDM). The aim of this study was to evaluate the cause of delayed gastric emptying in DM patients. Methods: In 16 controls, 16 non-insulin-dependent diabetes mellitus (NIDDM) patients and 23 IDDM patients, gastric emptying was studied using the ¹³C octanoic acid breath test. Breath samples were taken before a test meal labeled with 100mg of ¹³C octanoic acid, and at 15-min intervals over a 300-min period postprandially. Results: In all DM patients, the gastric emptying coefficient was lower than that in the controls (P < 0.05), and lag time and half-emptying time were significantly longer (P < 0.05). Both NIDDM and IDDM patients showed delayed ¹³CO₂ excretion compared with the controls, but IDDM patients showed more delayed gastric emptying than NIDDM patients (P < 0.05). There were no significant differences in sex, HbA1c level, or the rate of neuropathy between the two groups. Conclusions: IDDM patients showed delayed gastric emptying compared with NIDDM patients, and the ¹³C octanoic acid breath test is useful for evaluating DM patients with delayed gastric emptying.