Background & Aims Idiopathic gastroparesis (IG) is a common but poorly understood condition with significant morbidity. We studied characteristics of patients with IG enrolled in the National Institute of Diabetes and Digestive and Kidney Diseases Gastroparesis Clinical Research Consortium Registry. Methods Data from medical histories, symptom questionnaires, and 4-hour gastric emptying scintigraphy studies were obtained from patients with IG. Results The mean age of 243 patients with IG studied was 41 years; 88% were female, 46% were overweight, 50% had acute onset of symptoms, and 19% reported an initial infectious prodrome. Severe delay in gastric emptying (>35% retention at 4 hours) was present in 28% of patients. Predominant presenting symptoms were nausea (34%), vomiting (19%), an abdominal pain (23%). Women had more severe nausea, satiety, constipation, and overall gastroparesis symptoms. Patients who experienced acute-onset IG had worse nausea than those with insidious onset. Overweight patients had more bloating and gastric retention at 2 hours but less severe loss of appetite. Patients with severely delayed gastric emptying had worse vomiting and more severe loss of appetite and overall gastroparesis symptoms. Severe anxiety and depression were present in 36% and 18%, respectively. A total of 86% met criteria for functional dyspepsia, primarily postprandial distress syndrome. Conclusions IG is a disorder that primarily affects young women, beginning acutely in 50% of cases; unexpectedly, many patients are overweight. Severe delay in gastric emptying was associated with more severe symptoms of vomiting and loss of appetite. IG is a diverse syndrome that varies by sex, body mass, symptom onset, and delay in gastric emptying.

Abstract  Gastric emptying of digestible solids occurs after trituration of food particles. Non‐digestible solids are thought to empty with phase III of the migrating motor complex (MMC). The aim of this study was to determine if a non‐digestible capsule given with a meal empties from the stomach with return of the fasting phase III MMC or during the fed pattern with the solid meal. Fifteen normal subjects underwent antroduodenal manometry and ingestion of a radiolabelled meal and SmartPill wireless pH and pressure capsule. In five subjects, emptying of the SmartPill was studied in the fasting period by ingesting the SmartPill with radiolabelled water. The SmartPill emptied from the stomach within 6 h in 14 of 15 subjects. SmartPill pressure recordings showed high amplitude phasic contractions prior to emptying. SmartPill gastric residence time (261 ± 22 min) correlated strongly with time to the first phase III MMC (239 ± 23 min; r = 0.813; P < 0.01) and correlated moderately with solid‐phase gastric emptying (r = 0.606 with T‐50% and r = 0.565 with T‐90%). Nine of 14 subjects emptied the capsule with a phase III MMC. In five subjects, the SmartPill emptied with isolated distal antral contractions. In five subjects ingesting only water, SmartPill gastric residence time (92 ± 44 min) correlated with the time to the first phase III MMC (87 ± 30 min; r = 0.979; P < 0.01). The non‐digestible SmartPill given with a meal primarily empties from the stomach with the return of phase III MMCs occurring after emptying the solid‐phase meal. However, in some subjects, the SmartPill emptied with isolated antral contractions, an unappreciated mechanism for emptying of a non‐digestible solid.