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 100 mg 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.