The Gastroparesis Registry 4 (GpR4) is an observational study of patients with symptoms of gastroparesis (Gp) and functional dyspepsia (FD) with either delayed or normal gastric emptying. To better understand these disorders, this registry will capture demographic, clinical, physiological, questionnaire, and patient outcome data to characterize the patients and their clinical course. Participants will complete several questionnaires, complete a nutrient drink test and have a gastric emptying study.

This observational study of patients with symptoms of gastroparesis (Gp) and functional dyspepsia (FD) with either delayed or normal gastric emptying aims to assess the clinical, pathophysiological, and psychological similarities and differences between patients with Gp, FD.

The primary outcome will be the measure of symptom severity of gastroparesis and functional dyspepsia using the change in total score from the Patient Assessment of Upper Gastrointestinal Disorders Symptoms (PAGI SYM) from baseline to 48 weeks.

Inclusion Criteria:

• Age at least 18 years at initial screening visit
• Symptoms of Gp and/or FD of at least 12-weeks duration with varying degrees of nausea, vomiting, early satiety, postprandial fullness, abdominal pain, abdominal burning. Thus, patients can enter the GpR4 registry primarily with abdominal pain suggesting FD-Epigastric Pain Syndrome.
• Successful completion of gastric emptying scintigraphy of solids using the 4-hour Egg Beaters® protocol (or equivalent generic liquid egg white meal) within the last 9 months
• Negative upper endoscopy or upper radiographic GI series within 5 years of registration

Exclusion Criteria:

• Use of narcotic analgesics greater than three days per week
• Presence of other conditions that could explain the patient's symptoms such as:
• Pyloric or intestinal obstruction as evidenced by EGD, UGI, or Abdominal CT
• Active inflammatory bowel disease
• Known eosinophilic gastroenteritis or eosinophilic esophagitis
• Primary neurological conditions that can cause nausea and vomiting such as increased intracranial pressure, space occupying or inflammatory/infectious lesions
• Acute or chronic renal failure (serum creatinine >3 mg/dL) and/or on hemodialysis or peritoneal dialysis
• Acute liver failure or advanced liver disease (Child's B or C; a Child-Pugh-Turcotte (CPT) score of ≥7)
• Pancreatic disorder if present on pancreatic imaging or pancreatic function testing
• Prior gastric surgery including total or subtotal (near complete) gastric resection, esophagectomy, gastrojejunostomy, gastric bypass, gastric sleeve, pyloroplasty, pyloromyotomy, or any fundoplication (Nissen, Tor)
• Any other condition, which in the opinion of the investigator, could explain the symptoms or interfere with study requirements
• Females who are pregnant. A urine pregnancy test is routinely obtained on all females immediately prior to gastric emptying procedures.
• Inability to comply with or complete the gastric emptying scintigraphy test (including allergy to eggs)
• Inability to obtain informed consent

Adults over age 18, located in the United States, with symptoms of gastroparesis and/or functional dyspepsia.

Public use complete database will be submitted to the NIDDK Data Repository

Two years after the end of the funding period ends (2029)

An investigator interested in acquiring GpR4 study data or biospecimens should contact the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Central Repository