AGA Clinical Practice Update on Diagnosis and Management of Cannabinoid Hyperemesis Syndrome: Commentary.

DESCRIPTION: The purpose of this American Gastroenterological Association (AGA) Institute Clinical Practice Update (CPU) is to review the available evidence and provide expert advice regarding diagnosis and management of cannabinoid hyperemesis syndrome. METHODS: This CPU was commissioned and approved by the AGA Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the CPUC and external peer review through standard procedures of Gastroenterology. This expert commentary incorporates important as well as recently published studies in this field, and it reflects the experiences of the authors.

Benefits of Prokinetics, Gastroparesis Diet, or Neuromodulators Alone or in Combination for Symptoms of Gastroparesis.

BACKGROUND & AIMS: Prokinetics have limited effectiveness for treating symptoms of gastroparesis. Thus, alternative or adjunct therapies, such as gastroparesis diets or neuromodulators, are often prescribed. Their therapeutic benefits alone or in combination remain unclear. METHODS: One hundred and twenty-nine patients with symptoms of gastroparesis underwent wireless motility capsule gastric emptying time and gastric emptying scintigraphy. Based on test results, changes in therapy were recommended. Changes in Gastroparesis Cardinal Symptom Index (GCSI) and individual symptom scores over 6 months were related to recommendations for prokinetics, gastroparesis diet, or neuromodulators given as solo new therapies or in dual combinations. Multivariate analyses were performed to adjust for gastric emptying and other variables. RESULTS: In the whole group regardless of therapy, GCSI scores decreased by 0.53 points (interquartile range, -1.25 to 0.05; P < .0001) over 6 months. GCSI did not decrease for prokinetics as solo new therapy (P = .95). Conversely, neuromodulators as solo therapy decreased GCSI scores (P = .04) and all individual symptoms except nausea/vomiting (P = .86). Prokinetics combined with gastroparesis diets or neuromodulators improved GCSI scores (P ≤ .04) and most individual symptoms. Adjusting for gastric emptying time on multivariate analyses showed greater GCSI decreases for nondelayed emptying for neuromodulators as solo new therapy (P = .01). Gastric emptying scintigraphy, gender, diabetes, and functional dyspepsia did not influence responses to any treatment. CONCLUSIONS: Initiating prokinetics as solo new therapy had little benefit for patients with symptoms of gastroparesis. Neuromodulators as the only new therapy decreased symptoms other than nausea and vomiting, especially with nondelayed gastric emptying. Adding gastroparesis diets or neuromodulators to prokinetics offered relief, suggesting that combination therapies may be more useful in managing these patients. (ClinicalTrials.gov NCT02022826.).

Low Vitamin D Levels in Patients with Symptoms of Gastroparesis: Relationships with Nausea and Vomiting, Gastric Emptying and Gastric Myoelectrical Activity.

Patients with gastroparesis (Gp) often have diets deficient in calories, electrolytes, and vitamins. Vitamin D levels have been reported to be low in some patients with Gp but has not been systematically studied. AIMS: To determine vitamin D levels and relationships among symptoms, gastric emptying and gastric myoelectrical activity (GMA) in patients with symptoms of Gp. METHODS: 25-hydroxy-vitamin D was measured in patients at enrollment in the Gastroparesis Clinical Consortium Registry. Gastroparesis Cardinal Symptoms Index (GCSI), gastric emptying, and GMA before and after water load satiety test (WLST) were measured. GMA, expressed as percentage distribution of activity in normal and dysrhythmic ranges, was recorded using electrogastrography. RESULTS: Overall, vitamin D levels were low (< 30 ng/ml) in 288 of 513 (56.1%) patients with symptoms of Gp (206 of 376 (54.8%) patients with delayed gastric emptying (Gp) and 82 of 137 (59.9%) patients with symptoms of Gp and normal gastric emptying). Low vitamin D levels were associated with increased nausea and vomiting (P < 0.0001), but not with fullness or bloating subscores. Low vitamin D levels in patients with Gp were associated with greater meal retention at four hours (36% retention) compared with Gp patients with normal vitamin D levels (31% retention; P = 0.05). Low vitamin D in patients with normal gastric emptying was associated with decreased normal 3 cpm GMA before (P = 0.001) and increased tachygastria after WLST (P = 0.01). CONCLUSIONS: Low vitamin D levels are present in half the patients with symptoms of gastroparesis and are associated with nausea and vomiting and gastric neuromuscular dysfunction.

Relationships among intragastric meal distribution during gastric emptying scintigraphy, water consumption during water load satiety testing, and symptoms of gastroparesis.

Gastric emptying scintigraphy (GES) measures total gastric retention after a solid meal and can assess intragastric meal distribution (IMD). Water load satiety test (WLST) measures gastric capacity. Both IMD immediately after meal ingestion [ratio of proximal gastric counts after meal ingestion to total gastric counts at time 0 (IMD0)] and WLST (volume of water ingested over 5 min) are indirect measures of gastric accommodation. In this study, IMD0 and WLST were compared with each other and to symptoms of gastroparesis to gauge their clinical utility for assessing patients with symptoms of gastroparesis. Patients with symptoms of gastroparesis underwent GES to obtain gastric retention and IMD0, WLST, and filled out patient assessment of upper GI symptoms. A total of 234 patients with symptoms of gastroparesis were assessed (86 patients with diabetes, 130 idiopathic, 18 postfundoplication) and 175 (75%) delayed gastric emptying. Low IMD0 <0.568 suggesting initial rapid transit to the distal stomach was present in 8% and correlated with lower gastric retention, less heartburn, and lower volumes consumed during WLST. Low WLST volume (<238 mL) was present in 20% and associated with increased severity of early satiety, postprandial fullness, loss of appetite, and nausea. Low IMD0 is associated with less gastric retention and less heartburn. Volume of water consumed during WLST, while associated with IMD0, has associations with early satiety, postprandial fullness, loss of appetite, and nausea. Thus, IMD0 and WLST appear to overlap somewhat in their assessment of gastric physiology in adults with symptoms of gastroparesis but relate to different dyspeptic symptoms.NEW & NOTEWORTHY IMD0 and WLST were assessed for their clinical utility in assessing patients with symptoms of gastroparesis. Low IMD0 is associated with less gastric retention and less heartburn. Volume of water consumed during WLST, while associated with IMD0, has associations with early satiety, postprandial fullness, loss of appetite, and nausea. IMD0 and WLST appear to overlap somewhat in their assessment of gastric physiology in adults with symptoms of gastroparesis but relate to different dyspeptic symptoms.

Metoclopramide Nasal Spray in Women with Symptomatic Diabetic Gastroparesis: A Randomized, Double-Blind, Placebo-Controlled Phase 3 Study.

BACKGROUND & AIMS: Metoclopramide nasal spray (MNS) was developed as an alternative to oral metoclopramide. Prior phase 2 studies demonstrated efficacy in reducing symptoms in women, but not men with diabetic gastroparesis. The aim of this phase 3 study was to further determine the safety and efficacy of MNS compared with placebo in reducing symptoms of diabetic gastroparesis in women. METHODS: This US multicenter, randomized, double-blind, parallel group study enrolled women aged 18-75 years with diabetic gastroparesis and delayed gastric emptying. Subjects were randomized 1:1 to receive placebo or MNS 10 mg. The primary efficacy end point was change in mean daily Gastroparesis Symptom Assessment total score from baseline to Week 4. The Gastroparesis Symptom Assessment daily diary is a validated patient-reported outcome instrument that averages scores of nausea, early satiety, prolonged fullness, bloating, and upper abdominal pain on a 5-point ordinal scale. RESULTS: Two hundred and five subjects were randomized to receive placebo (n = 103) or MNS (n = 102). Overall, the MNS group did not experience a significant reduction in symptoms compared with the placebo group from baseline to Week 4 (P = .881). However, subjects with moderate-to-severe symptoms at baseline had a significant treatment effect from Weeks 1 to 3 (P < .05) and experienced a significant reduction in nausea and upper abdominal pain for all 4 weeks versus placebo (P < .05). Treatment-emergent adverse events were primarily mild to moderate with headache and abdominal pain reported most frequently. CONCLUSIONS: Although the primary end point was not met using all enrolled patients, treatment with MNS provided significant relief for women with moderate-to-severe diabetic gastroparesis symptoms. MNS was well tolerated and demonstrated a similar safety profile to placebo. (ClinicalTrials.gov identifier: NCT02025725.).

Postprandial symptoms in patients with symptoms of gastroparesis: roles of gastric emptying and accommodation.

Patients often are evaluated for gastroparesis because of symptoms occurring with meals. Gastric emptying scintigraphy (GES) is used for gastroparesis diagnosis, although results are not well correlated with gastroparesis symptoms. The aim of this study is to assess relationships between gastroparesis symptoms, gastric emptying (GE), and gastric accommodation (GA). Patients with symptoms of gastroparesis completed the Patient Assessment of Upper GI Symptoms (PAGI-SYM) and recorded symptoms during GES and water load satiety test (WLST), an indirect assessment for GA. A total of 109 patients with gastroparesis symptoms were assessed. Symptom severity increased after GES meal for stomach fullness, belching, nausea, abdominal burning, and abdominal pain. There was no difference in symptoms after meal between patients with delayed (n = 66) and normal (n = 42) GE. Diabetic patients (n = 26) had greater gastric retention than idiopathic patients (n = 78), but idiopathic patients had greater postprandial nausea, stomach fullness, and abdominal pain. Water consumed during WLST averaged 421 ± 245 mL. Idiopathic patients had greater nausea scores during WLST than diabetic patients. In comparison to those with normal water consumption (≥238 mL; n = 80), patients with impaired water ingestion (<238 mL; n = 26) had increased stomach fullness, early satiety, postprandial fullness, and loss of appetite on PAGI-SYM. Patients with delayed and normal GE had similar symptom profiles during GES and WLST. Idiopathic patients had less gastric retention but more symptoms after GES meal and after WLST compared with diabetic patients. Patients with impaired water consumption during WLST had increased symptoms by PAGI-SYM. These data suggest that impaired GA, rather than GE, may be important in explaining postprandial symptoms in patients with symptoms of gastroparesis.NEW & NOTEWORTHY Patients with delayed and normal gastric emptying (GE) had similar symptom profiles during gastric emptying scintigraphy (GES). Idiopathic patients with symptoms of gastroparesis had less gastric retention by GES; but more symptoms after GES meal and after water load satiety test (WLST) compared with diabetic patients. In patients with symptoms of gastroparesis, symptoms after WLST increased with decreasing water consumption. Early satiety and loss of appetite were associated with decreased water consumption during WLST. Thus, impaired accommodation and perhaps visceral hypersensitivity are important in explaining postprandial symptoms in gastroparesis.

Baseline Predictors of Longitudinal Changes in Symptom Severity and Quality of Life in Patients With Suspected Gastroparesis.

BACKGROUND & AIMS: Whether gastric emptying tests predict longitudinal outcomes in patients with symptoms of gastroparesis is unclear. We aimed to determine whether baseline gastric emptying tests and gut motility parameters could impact longitudinal symptom(s) and quality of life (QOL) in a prospective, observational cohort study of patients with symptoms of gastroparesis. METHODS: One hundred fifty patients with gastroparesis symptoms underwent simultaneous scintigraphy (GES) and wireless motility capsule (WMC) measurement of gastric emptying and other motility parameters. Patient Assessment of Upper Gastrointestinal Symptoms and Quality of Life were administered at baseline, and 3 and 6 months after testing. Multivariable generalized linear marginal models were fit to determine which baseline parameters predict longitudinal changes in symptoms and QOL. RESULTS: Overall upper GI symptoms and QOL scores were moderate in severity at baseline and significantly improved over 6 months. Clinical variables, including female gender, harder stools by Bristol stool form score, and presence of functional dyspepsia (FD) by Rome III criteria, were predictive of more severe upper GI symptoms. Even after controlling for these clinical factors, delayed gastric emptying by GES or WMC was associated with worse symptom severity and QOL scores. Low gastric and elevated small bowel contractile parameters by WMC were also independently associated with more severe upper GI symptoms and worse QOL scores. CONCLUSIONS: Baseline features, including demographic and clinical variables, delayed gastric emptying and abnormal gastrointestinal contractility, were independent predictors of more severe longitudinal symptoms and worse quality of life outcomes. These factors may help to risk stratify patients and guide treatment decisions. ClinicalTrials.gov no: NCT02022826.

Progress in Gastroparesis - A Narrative Review of the Work of the Gastroparesis Clinical Research Consortium.

The Gastroparesis Clinical Research Consortium is a multicenter coalition created and funded by the National Institutes of Diabetes and Digestive and Kidney Disorders, with a mission to advance understanding of the pathophysiology of gastroparesis and develop an effective treatment for patients with symptomatic gastroparesis. In this review, we summarize the results of the published Gastroparesis Clinical Research Consortium studies as a ready and convenient resource for gastroenterologists and others to provide a clear understanding of the consortium's experience and perspective on gastroparesis and related disorders.

Effect of Domperidone Therapy on Gastroparesis Symptoms: Results of a Dynamic Cohort Study by NIDDK Gastroparesis Consortium.

BACKGROUND & AIMS: The use of domperidone (DOM) for gastroparesis (GP) remains controversial and limited. We aimed to present outcomes of DOM therapy for treatment of patients participating in the multicenter National Institute of Diabetes and Digestive and Kidney Diseases Gastroparesis Clinical Research Consortium (GpCRC) Registries (GpR). METHODS: The GpCRC cohort consisted of patients with GP (75%) and with GP-like symptoms but with normal gastric emptying (25%). The DOM group initiated therapy during the 96 weeks of enrollment in GpR1 and GpR2. Patients who had previously taken or who were on DOM therapy at enrollment were excluded from this analysis. The control group did not use domperidone (non-DOM group) before or after enrollment. The following outcome measures were identified: change from baseline in Gastroparesis Cardinal Symptom Index total score, with 3 subscales, plus Gastroesophageal Reflux Disease and Patient Assessment of Upper Gastrointestinal Disorders-Quality of Life scores. RESULTS: Overall, of 748 patients, 181 (24%) were in the DOM group, whereas 567 were in the non-DOM group. Sixty-three percent of participants had idiopathic GP. At baseline, DOM patients compared with non-DOM patients were significantly younger, had lower body mass index, non-Hispanic ethnicity, a higher annual household income, lower narcotic utilization, lower supplemental and complimentary medication use, and were more likely to have delayed gastric emptying time, as well as worse nausea and fullness scores. Compared with non-DOM patients, DOM patients experienced moderate but significantly more improvement in GP outcome measures: Gastroparesis Cardinal Symptom Index total score (P = .003), nausea (P = .003), and fullness subscales (P =.005), upper abdominal pain score (P = .04), Gastroesophageal Reflux Disease score (P = .05), and Patient Assessment of Upper Gastrointestinal Disorders-Quality of Life score (P = .05). CONCLUSIONS: Utilizing the method of pragmatic modeling to evaluate long-term treatment of GP in a large GpCRC database, DOM treatment resulted in moderately but significantly improved GP. NOTE: This project was based on data generated by 2 GpCRC Registry studies recognized under the Clinicaltrial.gov numbers: NCT00398801 and NCT01696747 symptoms compared with a group receiving standard-of-care but not DOM.

Constipation in Patients With Symptoms of Gastroparesis: Analysis of Symptoms and Gastrointestinal Transit.

BACKGROUND & AIMS: Constipation can be an important symptom in some patients with gastroparesis. The aims were to: 1) Determine prevalence of constipation and delayed colonic transit in patients with symptoms of gastroparesis; 2) Correlate severity of constipation to severity of symptoms of gastroparesis; and 3) Relate severity of constipation to GI transit delays assessed by gastric emptying scintigraphy (GES) and wireless motility capsule (WMC). METHODS: Patients with symptoms of gastroparesis underwent gastric emptying scintigraphy (GES), wireless motility capsule (WMC) assessing gastric emptying, small bowel transit, and colonic transit, and questionnaires assessing symptoms using a modified Patient Assessment of Upper GI Symptoms [PAGI-SYM] and Rome III functional GI disorder questionnaire. RESULTS: Of 338 patients with symptoms of gastroparesis, 242 (71.5%) had delayed gastric emptying by scintigraphy; 298 (88.2%) also met criteria for functional dyspepsia. Severity of constipation was severe/very severe in 34% patients, moderate in 24%, and none/very mild/mild in 42%. Increasing severity of constipation was associated with increasing symptoms of gastroparesis and presence of irritable bowel syndrome (IBS). Severity of constipation was not associated with gastric retention on GES or WMC. Delayed colonic transit was present in 108 patients (32% of patients). Increasing severity of constipation was associated with increasing small bowel transit time, colonic transit time, and whole gut transit time. CONCLUSIONS: Severe/very severe constipation and delayed colon transit occurs in a third of patients with symptoms of gastroparesis. The severity of constipation is associated with severity of gastroparesis symptoms, presence of IBS, small bowel and colon transit delay, but not delay in gastric emptying. ClinicalTrials.gov Identifier: NCT01696747.

Functional Dyspepsia and Gastroparesis in Tertiary Care are Interchangeable Syndromes With Common Clinical and Pathologic Features.

BACKGROUND: The aim of this study was to clarify the pathophysiology of functional dyspepsia (FD), a highly prevalent gastrointestinal syndrome, and its relationship with the better-understood syndrome of gastroparesis. METHODS: Adult patients with chronic upper gastrointestinal symptoms were followed up prospectively for 48 weeks in multi-center registry studies. Patients were classified as having gastroparesis if gastric emptying was delayed; if not, they were labeled as having FD if they met Rome III criteria. Study analysis was conducted using analysis of covariance and regression models. RESULTS: Of 944 patients enrolled during a 12-year period, 720 (76%) were in the gastroparesis group and 224 (24%) in the FD group. Baseline clinical characteristics and severity of upper gastrointestinal symptoms were highly similar. The 48-week clinical outcome was also similar but at this time 42% of patients with an initial diagnosis of gastroparesis were reclassified as FD based on gastric-emptying results at this time point; conversely, 37% of patients with FD were reclassified as having gastroparesis. Change in either direction was not associated with any difference in symptom severity changes. Full-thickness biopsies of the stomach showed loss of interstitial cells of Cajal and CD206+ macrophages in both groups compared with obese controls. CONCLUSIONS: A year after initial classification, patients with FD and gastroparesis, as seen in tertiary referral centers at least, are not distinguishable based on clinical and pathologic features or based on assessment of gastric emptying. Gastric-emptying results are labile and do not reliably capture the pathophysiology of clinical symptoms in either condition. FD and gastroparesis are unified by characteristic pathologic features and should be considered as part of the same spectrum of truly "organic" gastric neuromuscular disorders. CLINICALTRIALS. GOV IDENTIFIER: NCT00398801, NCT01696747.

Small Bowel Dysmotility, Pseudoobstruction, and Functional Correlation with Histopathology: Lessons Learned.

PURPOSE OF REVIEW: Small bowel dysmotility is a broad heterogeneous term that encompasses a wide range of gastrointestinal disorders resulting from abnormal gut motility. Chronic intestinal pseudo-obstruction (CIPO) is a severe, rare, and complex small bowel motility disorder at the extreme end of this spectrum. It is characterized by failure of the intestinal tract to propel contents, which results in signs and symptoms of bowel obstruction albeit in the absence of any obstructive lesion(s). In this article, we discuss up-to-date diagnostic techniques, management options, and histopathological findings in CIPO. RECENT FINDINGS: We will emphasize the latest diagnostic methodologies and therapeutic options as well as enteric histopathologic abnormalities in patients with CIPO. CIPO continues to be a clinical challenge. Several novel pharmacological agents hold promise including gastrointestinal hormone agonists and prokinetics. Furthermore, histopathologic findings may help guide therapy and provide further prognostic significance. At present, nutritional support, symptom management, and avoidance of long-term complications are the mainstay of treatment in CIPO.

Central Nervous System Mechanisms of Nausea in Gastroparesis: An fMRI-Based Case-Control Study.

BACKGROUND/AIMS: Nausea is a major complaint of gastroparesis (GP), and the pathophysiology of this condition is poorly understood. Therefore, this study utilized fMRI to investigate the possible central nervous system (CNS) mechanisms of nausea in 10 GP patients versus 8 healthy controls (HCs). METHODS: Nausea severity was assessed on a 0-10 scale and presented as mean ± SD. Nausea was increased from baseline utilizing up to 30 min of visual stimulation (VS). Functional network connectivity was measured with fMRI at baseline and after 30 min of VS. fMRI data were preprocessed using statistical parametric mapping software. Thirty-four independent components were identified as meaningful resting-state networks (RSNs) by group independent component analysis. The Functional Network Connectivity (FNC) among 5 RSNs considered important in CNS nausea mechanisms was calculated as the Pearson's pairwise correlation. RESULTS: Baseline nausea score in GP patients was 2.7 ± 2.0 and increased to 7.0 ± 1.5 after stimulation (P < 0.01). In HCs nausea scores did not increase from baseline after stimulus (0.3 ± 0.5). When comparing GP patients to HCs after VS, a significant reduction (P < 0.001) in bilateral insula network connectivity compared to the right insula network was detected. No significant differences in connectivity were noted among the other RSNs. Additionally, the average gray matter volume was non-significantly reduced in the insula in GP patients compared to HC. CONCLUSIONS: The insula connectivity network is impaired in nauseated GP patients. This phenomenon could explain the susceptibility of GP patients to nausea or may have resulted from a state of chronic nausea.

Marijuana Use in Patients with Symptoms of Gastroparesis: Prevalence, Patient Characteristics, and Perceived Benefit.

BACKGROUND: Marijuana may be used by some patients with gastroparesis (Gp) for its potential antiemetic, orexigenic, and pain-relieving effects. AIMS: The aim of this study was to describe the use of marijuana by patients for symptoms of Gp, assessing prevalence of use, patient characteristics, and patients' perceived benefit on their symptoms of Gp. METHODS: Patients with symptoms of Gp underwent history and physical examination, gastric emptying scintigraphy, and questionnaires assessing symptoms. Patients were asked about the current use of medications and alternative medications including marijuana. RESULTS: Fifty-nine of 506 (11.7%) patients with symptoms of Gp reported current marijuana use, being similar among patients with delayed and normal gastric emptying and similar in idiopathic and diabetic patients. Patients using marijuana were younger, more often current tobacco smokers, less likely to be a college graduate, married or have income > $50,000. Patients using marijuana had higher nausea/vomiting subscore (2.7 vs 2.1; p = 0.002), higher upper abdominal pain subscore (3.5 vs 2.9; p = 0.003), more likely to be using promethazine (37 vs 25%; p = 0.05) and dronabinol (17 vs 3%; p < 0.0001). Of patients using marijuana, 51% had been using it for more than 2 years, 47% were using this once or more per day, and 81% of marijuana users rated their benefit from marijuana as better or much better. CONCLUSIONS: A subset of patients (12%) with symptoms of Gp use marijuana. Patients with severe nausea and abdominal pain were more likely to use marijuana and perceive it to be beneficial for their symptoms. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01696747.

Proteomics in gastroparesis: unique and overlapping protein signatures in diabetic and idiopathic gastroparesis.

Macrophage-based immune dysregulation plays a critical role in development of delayed gastric emptying in diabetic mice. Loss of anti-inflammatory macrophages and increased expression of genes associated with pro-inflammatory macrophages has been reported in full-thickness gastric biopsies from gastroparesis patients. We aimed to determine broader protein expression (proteomics) and protein-based signaling pathways in gastric biopsies of diabetic (DG) and idiopathic gastroparesis (IG) patients. Additionally, we determined correlations between protein expressions, gastric emptying, and symptoms. Full-thickness gastric antrum biopsies were obtained from nine DG patients, seven IG patients, and five nondiabetic controls. Aptamer-based SomaLogic tissue scan that quantitatively identifies 1,305 human proteins was used. Protein fold changes were computed, and differential expressions were calculated using Limma. Ingenuity pathway analysis and correlations were carried out. Multiple-testing corrected P < 0.05 was considered statistically significant. Seventy-three proteins were differentially expressed in DG, 132 proteins were differentially expressed in IG, and 40 proteins were common to DG and IG. In both DG and IG, "Role of Macrophages, Fibroblasts and Endothelial Cells" was the most statistically significant altered pathway [DG false discovery rate (FDR) = 7.9 × 10-9; IG FDR = 6.3 × 10-12]. In DG, properdin expression correlated with GCSI bloating (r = -0.99, FDR = 0.02) and expressions of prostaglandin G/H synthase 2, protein kinase C-ζ type, and complement C2 correlated with 4 h gastric retention (r = -0.97, FDR = 0.03 for all). No correlations were found between proteins and symptoms or gastric emptying in IG. Protein expression changes suggest a central role of macrophage-driven immune dysregulation in gastroparesis, specifically, complement activation in diabetic gastroparesis.NEW & NOTEWORTHY This study uses SOMAscan, a novel proteomics assay for determination of altered proteins and associated molecular pathways in human gastroparesis. Seventy-three proteins were changed in diabetic gastroparesis, 132 in idiopathic gastroparesis compared with controls. Forty proteins were common in both. Macrophage-based immune dysregulation pathway was most significantly affected in both diabetic and idiopathic gastroparesis. Proteins involved in the complement and prostaglandin synthesis pathway were associated with symptoms and gastric emptying delay in diabetic gastroparesis.

Validation of Diagnostic and Performance Characteristics of the Wireless Motility Capsule in Patients With Suspected Gastroparesis.

BACKGROUND & AIMS: It is a challenge to make a diagnosis of gastroparesis. There is good agreement in results from wireless motility capsule (WMC) analysis and gastric emptying scintigraphy (GES), but the diagnostic yield of WMC is unclear and the accuracy of this method has not been validated. We compared the performance characteristics of WMC vs GES in assessing gastric emptying in patients with suspected gastroparesis. METHODS: We performed a prospective study of 167 subjects with gastroparesis (53 with diabetes and 114 without) at 10 centers, from 2013 through 2016. Subjects were assessed simultaneously by GES and with a WMC to measure gastric emptying and regional transit. Delayed gastric emptying by GES was defined as more than 10% meal retention at 4 hrs whereas delayed gastric emptying by WMC was defined as more than 5 hrs for passage of the capsule into the duodenum; a severe delay in gastric emptying was defined as a gastric emptying time of more than 12 hrs by WMC or more than 35% retention at 4 hrs by GES. Rapid gastric emptying was defined as less than 38% meal retention at 1 hr based on by GES or gastric emptying times less than 1:45 hrs by WMC. We compared diagnostic and performance characteristics of GES vs WMC. RESULTS: Delayed gastric emptying was detected in a higher proportion of subjects by WMC (34.6%) than by GES (24.5%) (P=.009). Overall agreement in results between methods was 75.7% (kappa=0.42). In subjects without diabetes, the WMC detected a higher proportion of subjects with delayed gastric emptying (33.3%) than GES (17.1%) (P < .001). A higher proportion of subjects with diabetes had delayed gastric emptying detected by GES (41.7%) compared with non-diabetic subjects (17.1%) (P=.002). Severe delays in gastric emptying were observed in a higher proportion of subjects by WMC (13.8%) than by GES (6.9%) (P = .02). Rapid gastric emptying was detected in a higher proportion of subjects by GES (13.8%) than by WMC (3.3%) (P < .001). Regional and generalized transit abnormalities were observed in 61.8% subjects and only detected by WMC. CONCLUSION: Although there is agreement in analysis of gastric emptying by GES vs WMC, WMC provides higher diagnostic yield than GES. WMC detects delayed gastric emptying more frequently than GES and identifies extra-gastric transit abnormalities. Diabetic vs non-diabetic subjects have different results from GES vs WMC. These findings could affect management of patients with suspected gastroparesis. ClinicalTrials.gov no: NCT02022826.

Opioid Use and Potency Are Associated With Clinical Features, Quality of Life, and Use of Resources in Patients With Gastroparesis.

BACKGROUND & AIMS: Many patients with gastroparesis are prescribed opioids for pain control, but indications for opioid prescriptions and the relationship of opioid use to gastroparesis manifestations are undefined. We characterized associations of use of potent vs weaker opioids and presentations of diabetic and idiopathic gastroparesis. METHODS: We collected data on symptoms, gastric emptying, quality of life, and health care resource use from 583 patients with gastroparesis (>10% 4-h scintigraphic retention) from the National Institute of Diabetes and Digestive and Kidney Diseases Gastroparesis Consortium, from January 2007 through November 2016. Patients completed medical questionnaires that included questions about opioid use. The opioid(s) were categorized for potency relative to oral morphine. Symptom severities were quantified by Patient Assessment of Upper Gastrointestinal Disorders Symptoms questionnaires. Subgroup analyses compared patients on potent vs weaker opioids and opioid effects in diabetic vs idiopathic etiologies. RESULTS: Forty-one percent of patients were taking opioids; 82% of these took potent agents (morphine, hydrocodone, oxycodone, methadone, hydromorphone, buprenorphine, or fentanyl). Abdominal pain was the reason for prescription for 61% of patients taking opioids. Mean scores for gastroparesis, nausea/vomiting, bloating/distention, abdominal pain, and constipation scores were higher in opioid users (P ≤ .05). Opioid use was associated with greater levels of gastric retention, worse quality of life, increased hospitalization, and increased use of antiemetic and pain modulator medications compared with nonusers (P ≤ .03). Use of potent opioids was associated with worse gastroparesis, nausea/vomiting, upper abdominal pain, and quality-of-life scores, and more hospitalizations compared with weaker opioids (tapentadol, tramadol, codeine, or propoxyphene) (P ≤ .05). Opioid use was associated with larger increases in gastric retention in patients with idiopathic vs diabetic gastroparesis (P = .008). CONCLUSIONS: Opioid use is prevalent among patients with diabetic or idiopathic gastroparesis, and is associated with worse symptoms, delays in gastric emptying, and lower quality of life, as well as greater use of resources. Potent opioids are associated with larger effects than weaker agents. These findings form a basis for studies to characterize adverse outcomes of opioid use in patients with gastroparesis and to help identify those who might benefit from interventions to prevent opioid overuse.

Aprepitant Has Mixed Effects on Nausea and Reduces Other Symptoms in Patients With Gastroparesis and Related Disorders.

BACKGROUND & AIMS: There are few effective treatments for nausea and other symptoms in patients with gastroparesis and related syndromes. We performed a randomized trial of the ability of the neurokinin-1 receptor antagonist aprepitant to reduce symptoms in patients with chronic nausea and vomiting caused by gastroparesis or gastroparesis-like syndrome. METHODS: We conducted a 4-week multicenter, double-masked trial of 126 patients with at least moderate symptoms of chronic nausea and vomiting of presumed gastric origin for a minimum of 6 months. Patients were randomly assigned to groups given oral aprepitant (125 mg/day, n = 63) or placebo (n = 63). The primary outcome from the intention-to-treat analysis was reduction in nausea, defined as a decrease of 25 mm or more, or absolute level below 25 mm, on a daily patient-reported 0-to-100 visual analog scale (VAS) of nausea severity. We calculated relative risks of nausea improvement using stratified Cochran-Mental-Haenszel analysis. RESULTS: Aprepitant did not reduce symptoms of nausea, based on the primary outcome measure (46% reduction in the VAS score in the aprepitant group vs 40% reduction in the placebo group; relative risk, 1.2; 95% CI, 0.8-1.7) (P = .43). However, patients in the aprepitant group had significant changes in secondary outcomes such as reduction in symptom severity (measured by the 0-5 Gastroparesis Clinical Symptom Index) for nausea (1.8 vs 1.0; P = .005), vomiting (1.6 vs 0.5; P = .001), and overall symptoms (1.3 vs 0.7; P = .001). Adverse events, predominantly mild or moderate in severity grade, were more common in aprepitant (22 of 63 patients, 35% vs 11 of 63, 17% in the placebo group) (P = .04). CONCLUSIONS: In a randomized trial of patients with chronic nausea and vomiting caused by gastroparesis or gastroparesis-like syndrome, aprepitant did not reduce the severity of nausea when reduction in VAS score was used as the primary outcome. However, aprepitant had varying effects on secondary outcomes of symptom improvement. These findings support the need to identify appropriate patient outcomes for trials of therapies for gastroparesis, including potential additional trials for aprepitant. ClinicalTrials.gov no: NCT01149369.

Ethnic, Racial, and Sex Differences in Etiology, Symptoms, Treatment, and Symptom Outcomes of Patients With Gastroparesis.

BACKGROUND & AIMS: Gastroparesis is a chronic disorder of the stomach characterized by nausea, vomiting, early satiety, postprandial fullness, and abdominal pain. There is limited information on gastroparesis in minority populations. We assessed ethnic, racial, and sex variations in the etiology, symptoms, quality of life, gastric emptying, treatments, and symptom outcomes of patients with gastroparesis. METHODS: We collected information from the National Institutes of Health Gastroparesis Consortium on 718 adult patients, from September 2007 through December 2017. Patients were followed every 4 or 6 months, when data were collected on medical histories, symptoms (based on answers to the PAGI-SYM questionnaires), and quality of life (based on SF-36). Follow-up information collected at 1 year (48 week) was used in this analysis. Comparisons were made between patients of self-reported non-Hispanic white, non-Hispanic black, and Hispanic ethnicities, as well as and between male and female patients. RESULTS: Our final analysis included 552 non-Hispanic whites (77%), 83 persons of Hispanic ethnicity (12%), 62 non-Hispanic blacks (9%), 603 women (84%), and 115 men (16%). A significantly higher proportion of non-Hispanic blacks (60%) had gastroparesis of diabetic etiology than of non-Hispanic whites (28%); non-Hispanic blacks also had more severe retching (2.5 vs 1.7 score) and vomiting (2.9 vs 1.8 score) and a higher percentage were hospitalized in the past year (66% vs 38%). A significantly higher proportion of Hispanics had gastroparesis of diabetic etiology (59%) than non-Hispanic whites (28%), but Hispanics had less-severe nausea (2.7 vs 3.3 score), less early satiety (3.0 vs 3.5 score), and a lower proportion used domperidone (8% vs 21%) or had a peripherally inserted central catheter (1% vs 7%). A higher proportion of women had gastroparesis of idiopathic etiology (69%) than men (46%); women had more severe symptoms of stomach fullness (3.6 vs 3.1 score), early satiety (3.5 vs 2.9 score), postprandial fullness (3.7 vs 3.1 score), bloating (3.3 vs 2.6 score), stomach visibly larger (3.0 vs 2.1 score), and upper abdominal pain (2.9 vs 2.4 score). A lower proportion of women were hospitalized in past year (39% vs 53% of men). CONCLUSIONS: In patients with gastroparesis, etiologies, symptom severity, and treatments vary among races and ethnicities and between sexes. ClinicalTrials.gov Identifier: NCT01696747.

Lactulose Breath Testing as a Predictor of Response to Rifaximin in Patients With Irritable Bowel Syndrome With Diarrhea.

OBJECTIVES: The nonsystemic antibiotic rifaximin is indicated for irritable bowel syndrome with diarrhea (IBS-D) in adults; however, determinants of response remain unclear. The utility of lactulose breath testing (LBT) in predicting response to rifaximin was examined. METHODS: Adults with IBS-D received open-label rifaximin 550 mg 3 times daily for 2 weeks, followed by a 4-week posttreatment assessment period. Thirteen centers prospectively participated in this substudy. LBT was conducted before (day 1) and after (day 14) therapy (breath samples obtained every 15 minutes; up to 240 minutes). Patient response (decrease from baseline of ≥30% in abdominal pain and ≥50% decrease in frequency of mushy/watery stool), symptom improvement, and the relationship of clinical outcomes to LBT results were assessed. RESULTS: A total of 93 patients were included; 62 (66.7%) had positive baseline LBT results. Overall, 48.4% (45/93) of patients responded to rifaximin; of these, 59.7% (37/62) had a positive baseline LBT vs 25.8% (8/31) with a negative LBT (P = 0.002; odds ratio 4.3, 95% confidence interval, 1.5-12.7). Patients with a positive baseline LBT result experienced significantly greater improvement from baseline in 6 of 7 individual IBS symptoms. LBT results after rifaximin therapy did not correlate with clinical response in the 86 patients with evaluable breath tests (P = 0.21); however, patients whose LBT results normalized after rifaximin had the highest response rate of 76.5% (13/17). DISCUSSION: A positive baseline LBT result predicted a higher likelihood of response to rifaximin in IBS-D, suggesting a gut microbiome modulatory mechanism of action for rifaximin.