Potato-Lactulose Breath Hydrogen Testing as a Function of Gastric Motility in Diabetes Mellitus

Abstract

Objective: Scintigraphic determination of gastric emptying is the current standard for the assessment of gastric motility and the diagnosis of diabetic gastroparesis. However, such studies are expensive, inconvenient, and involve exposure to radiation. Because the time course of breath hydrogen (H₂) excretion after ingestion of lactulose correlates with upper gastrointestinal transit time, we hypothesized that patients with diabetic gastroparesis would exhibit prolonged breath H₂ excretion after ingestion of a test meal containing complex carbohydrate and lactulose compared to subjects without diabetes and subjects with diabetes but without gastroparesis. Research Design and Methods: Ten healthy subjects without diabetes, 10 subjects with diabetes but without gastroparesis (gastric emptying T_1/2,T_1/2 < 90 minutes), and 10 subjects with diabetes and previously diagnosed gastroparesis (T_1/2 > 90 minutes) were admitted for a single 24-hour study. Gastric motility agents were withheld 24 hours prior to the study. Euglycemia was established and maintained overnight in subjects with diabetes with continuous intravenous insulin infusion. At 6:00 _AM, all subjects ingested a breakfast containing 100 g of cooked potato starch and 20 g lactulose. Breath H2 excretion was monitored at baseline and every 30 minutes for 12 hours after ingestion of the test meal. Results: Twelve hours after ingestion of the test meal, raw and baseline adjusted breath H2 excretion was significantly elevated in the gastroparesis group compared to the unaffected group with diabetes and the group without diabetes (p < 0.001). The baseline and 12-hour data points were adequate to discriminate between normal and delayed gastric emptying. Conclusions : We conclude that patients with previously diagnosed gastroparesis exhibit prolonged breath H2 excretion after ingestion of a test meal. This test may prove to be a safe, reliable, and affordable outpatient screening test for diabetic gastroparesis.