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INTRODUCTION: Controlling for potential placebo effects is an important aspect of gaining an accurate estimate of how much the therapy alone changes patient symptoms or other end points. When the placebo effect is large, this can lead to only a small fraction of changes seen in the active therapy group being attributed to the therapy itself. This problem has been well studied in some disorders of brain-gut interaction but not in functional dyspepsia where placebo response rates of 40% and higher have been reported. Understanding risk factors for placebo response might lead to changes in trial design that could reduce the magnitude of the problem. This study sought to identify risk factors for the placebo effect in a functional dyspepsia clinical trial with a longer-term aim of suggesting trial design changes that might minimize the problem. METHODS: A secondary analysis of the clinical trial data was undertaken using 2 arms deemed to involve placebo therapy. Potential predictors were drawn from a wide range of patient characteristics including psychological, clinical, and physiological features. RESULTS: Predictors of a stronger placebo effect on the gastrointestinal symptom rating scale included higher functional dyspepsia symptom burden at baseline (b 5 20.101), coexisting irritable bowel syndrome (b 5 20.436), and higher scores on the Nepean Dyspepsia Index eat/drink domain (20.005). Baseline symptom burden and coexisting irritable bowel syndrome were found to be independent placebo predictors, explaining 13% of the variance in change in gastrointestinal symptom rating scale. Anxiety, childhood sexual abuse, sleep amount, and frequent abdominal pain were also found to be predictors of change in individual symptom scores. DISCUSSION: The findings of this study yield actionable insights into trial methodology that may help to reduce the magnitude of the placebo effect in future functional dyspepsia treatment trials. [ABSTRACT FROM AUTHOR]

Placebo responses to an apparently inactive intervention are of interest from a scientific perspective as they suggest possible mechanism(s) at work beyond the intervention itself. They are also of interest from a clinical trials perspective since high rates of placebo response limit the potential to demonstrate worthwhile efficacy of a new intervention. This mini‐review was motivated by the work of Bosman and colleagues(Neurogastroenterol Motil, 2022, and e14474) that is published in this issue of the journal in which they report on a systematic review and meta‐analysis of placebo response in functional dyspepsia clinical trials. The review sets the scene for their work by putting it in the context of other disorders of brain–gut interaction and extra‐gastrointestinal disorders. The review canvasses potential mechanisms of placebo response. [ABSTRACT FROM AUTHOR]

Background: There is limited empirical evidence of the magnitude of the discrepancy between prospectively recorded gastrointestinal symptom burden and that reported in recall questionnaires. Further, potential sources of the discrepancy are largely unknown. This study sought to quantify the discrepancy and to evaluate the potential role of mood disorder and emotion regulation in the discrepancy. Methods: One hundred and forty nine subjects (mean age 20 years, 75% female) who met Rome IV criteria for irritable bowel syndrome and/or functional dyspepsia completed a 7‐day prospective recording of the symptoms on a smartphone implemented ecological momentary assessment app, and then on day 8 were asked to recall their symptoms for the preceding 7 days. Key Results: Gastrointestinal symptom burden assessed by recall was exaggerated relative to that recorded prospectively. The discrepancy was moderate for overall score (Cohen d = 0.52), abdominal pain (d = 0.61) and indigestion (d = 0.49). The discrepancy was generally larger among subjects who reported a physician diagnosis of a gastrointestinal condition with d = 0.87 for overall score and d = 0.89 for abdominal pain. A number of correlations between the discrepancy and psychological traits were identified, including neuroticism with diarrhea discrepancy (r = 0.23, p = 0.004) and visceral‐specific anxiety with abdominal pain discrepancy (r = −0.18, p = 0.03). There was no evidence of recency or Hawthorne (observer) effects. Conclusions and Inferences: Reports of gastrointestinal symptoms obtained via recall are likely to be exaggerated relative to the actual patient experience, particularly among healthcare seekers. While psychological traits are likely to play some role, much more needs to be understood about the discrepancy. [ABSTRACT FROM AUTHOR]

Summary: Background: Rumination syndrome is a functional gastroduodenal disorder characterised by effortless regurgitation of recently ingested food. Emerging evidence reports duodenal eosinophilic inflammation in a subset, suggesting a shared pathophysiology with functional dyspepsia (FD). Aim: To assess the clinical features of rumination syndrome and FD in a community‐based study. Methods: We mailed a survey assessing gastrointestinal symptoms, diet and psychological symptoms to 9835 residents of Olmsted County, MN, USA in 2017‐2018; diagnostic codes were obtained from linked clinical records. The two disorders were assessed as mutually exclusive in 'pure' forms with a separate overlap group, all compared to a control group not meeting criteria for either. Prevalence of associations, and univariate and independent associations with predictors were assessed by logistic regression. Results: Prevalence of rumination syndrome and FD were 5.8% and 7.1%, respectively; the overlap was 3.83‐times more likely than expected by chance. Independent predictors for rumination (odds ratio (OR), 95% confidence interval (CI)) were female gender (1.79, 1.21‐2.63), smoking (1.89, 1.28‐2.78), gluten‐free diet (1.58, 1.14‐2.19), allergic rhinitis (1.45, 1.01‐2.08) and depression (1.10, 1.05‐1.16). FD was independently associated with female gender, depression, non‐coeliac wheat sensitivity, migraine, irritable bowel syndrome and somatic symptoms. A similar reported efficacy (≥54%) of low fat or dairy‐free diets was found with both disorders (P = 0.53 and P = 1.00, respectively). The strongest independent associations with overlapping FD and rumination syndrome were a history of rheumatoid arthritis (3.93, 1.28‐12.06) and asthma (3.02, 1.44‐6.34). Conclusion: Rumination syndrome overlaps with FD with a shared risk factor profile, suggesting a common pathophysiology. [ABSTRACT FROM AUTHOR]

Objectives: To determine the incidence of self-reported non-coeliac wheat sensitivity (SR-NCWS) and factors associated with its onset and resolution; to describe the prevalence of factors associated with gluten avoidance.Design: Longitudinal cohort study; analysis of responses to self-administered validated questionnaires (Digestive Health and Wellbeing surveys, 2015 and 2018).Setting, Participants: Subset of an adult population sample randomly selected in 2015 from the electoral rolls for the Newcastle and Gosford regions of New South Wales.Main Outcome Measures: Prevalence of SR-NCWS (2015, 2018) and incidence and resolution of SR-NCWS, each by demographic and medical factors; prevalence of gluten avoidance and reasons for gluten avoidance (2018).Results: 1322 of 2185 eligible participants completed the 2018 survey (response rate, 60.5%). The prevalence of SR-NCWS was similar in 2015 (13.8%; 95% CI, 12.0-15.8%) and 2018 (13.9%; 95% CI, 12.1-15.9%); 69 of 1301 respondents (5.3%) reported developing new onset (incident) SR-NCWS between 2015 and 2018 (incidence, 1.8% per year). Incident SR-NCWS was significantly associated with a diagnosis of functional dyspepsia, and negatively associated with being male or older. Gluten avoidance was reported in 2018 by 24.2% of respondents (20.5% partial, 3.8% complete avoidance); general health was the most frequent reason for avoidance (168 of 316 avoiders, 53%). All 13 participants with coeliac disease, 56 of 138 with irritable bowel syndrome (41%), and 69 of 237 with functional dyspepsia (29%) avoided dietary gluten.Conclusions: The prevalence of SR-NCWS was similar in 2015 and 2018. Baseline (2015) and incident SR-NCWS (2018) were each associated with functional gastrointestinal disorders. The number of people avoiding dietary gluten exceeds that of people with coeliac disease or SR-NCWS, and general health considerations and abdominal symptoms are the most frequently reported reasons for avoidance. [ABSTRACT FROM AUTHOR]

The article focuses on the study which proposes a multidimensional model of psychobiological interactions in Functional Dyspepsia (FD), indigestion. It mentions the objective of the study was to investigate the interaction of gastric sensorimotor function and somatization to cause FD. It states that two types of analysis were used namely Confirmatory Factor Analysis (CFA) and Structural Equation Modeling (SEM) to examine the latent variables and relationship between these variables.

OBJECTIVE: A link between dyspepsia symptoms and weight loss is controversial. We aimed to determine whether or not weight loss is a marker of dyspepsia. METHODS: Independent community-based cross-sectional studies. Subjects were randomly selected from the general population in Sydney, Australia. All subjects completed validated community health surveys. Two distinct data collections were used; the first as a training sample (N = 888) and the second as a validation sample to confirm the findings of the first (N = 2,907). The study was focused on weight loss, which was categorized as (a) any weight loss, (b) substantive weight loss (≥3 kg), and (c) weight loss expressed as percentage of body weight. RESULTS: All dyspepsia symptoms studied were positively associated with weight loss although the strength of association did vary. Nausea and vomiting were most strongly associated with weight loss as were meal-related complaints such as postprandial fullness. Similarly, clusters formed based on symptoms were strongly differentiated in terms of weight loss with clusters characterized by nausea, vomiting, and early satiety/postprandial fullness reporting 25–30% weight loss prevalence over the previous 3 months compared with around 10% prevalence in clusters characterized by low dyspepsia symptom burden. Weight loss ≥3 kg followed a similar pattern but with a prevalence approximately half that of any weight loss, while weight loss expressed as percentage of body weight followed the same pattern. CONCLUSIONS: Dyspepsia symptoms are clearly and, in some cases, strongly associated with weight loss, both any loss of weight and substantive weight loss. Weight loss should be considered a warning symptom of dyspepsia. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Reporting of symptoms and visceral sensations in functional dyspepsia is subjective and influenced by such factors as somatization and depression. To better understand the role of these factors in symptom reporting, somatization, somatosensory amplification, alexithymia, and depression were evaluated in patients with functional dyspepsia undergoing a water load test.METHODS: Sixty-seven controls and 103 patients with functional dyspepsia underwent a 5-min water load. Participants both recalled dyspeptic symptoms from the previous 2 wk and rated symptoms of nausea, fullness, and bloating during water load. Participants also completed the symptom checklist-90-R, somatosensory amplification scale, and the Toronto alexithymia scale.RESULTS: Compared with controls, patients with dyspepsia had greater psychiatric distress and higher scores for somatosensory amplification and alexithymia. Patients with dyspepsia also reported fullness at significantly lower volumes of water and experienced greater symptoms during water load than controls. Receiver operator characteristics of water load volume and provoked symptoms suggested that water load (WL) volume was a better discriminator of patients with dyspepsia from controls. Patients with dyspepsia recalled significantly more symptoms in the 2 wk prior to study. Symptoms provoked during WL were not associated with measured psychiatric constructs in either controls or patients with dyspepsia whereas recalled symptoms in patients with functional dyspepsia were significantly associated with several measured psychiatric constructs.CONCLUSIONS: Patients with functional dyspepsia report fullness at lower volumes of ingested water and develop more symptoms than do controls. Water load volume better discriminates patients with dyspepsia from controls than does symptoms provoked during water load. Provoked symptoms in dyspepsia are not associated with measured psychiatric constructs but recalled symptoms are.(Am J Gastroenterol 2005;100:1–6) [ABSTRACT FROM AUTHOR]

Background & Aims: Psychosocial factors may influence both symptom generation and reporting in functional dyspepsia. We determined the presence and severity of these factors as well as their relationship to dyspeptic symptoms in patients with functional dyspepsia and healthy subjects. Methods: A total of 151 consecutive patients with functional dyspepsia referred chiefly from primary care clinics and 90 healthy subjects rated 15 dyspeptic symptoms. Participants completed the Medical Outcomes Study SF-36 and Symptom Checklist-90–revised. Results: Functional dyspepsia patients reported significantly higher symptom scores, poorer quality of life, and greater psychiatric distress than healthy subjects. For both patients and healthy subjects, increasing symptom scores were associated with significant decreases in the Physical but not the Mental Components Summary of the Medical Outcomes Study SF-36. Although functional dyspepsia patients showed significantly greater psychiatric distress than healthy subjects, symptoms were correlated only modestly with scores on the Symptom Checklist-90–revised. A number of symptoms showed significant but modest correlations (rs < .30) with the somatization scale with chest burning correlating most strongly (rs = .48). Chest burning also was correlated significantly with depression, anxiety, and phobic anxiety. Functional dyspepsia patients at a secondary level of care have greater symptom severity, poorer quality of life, and greater psychiatric distress than healthy subjects. Increasing symptom severity is associated with poorer quality of life primarily in the areas of physical and social functioning. With the exception of chest burning, symptoms are not correlated highly with psychiatric distress. Conclusions: These data suggest that although functional dyspepsia patients experience increased psychiatric distress, symptom severity and psychiatric distress are not associated strongly. [Copyright &y& Elsevier]

Gastric sensation and accommodation are studied by barostat, but this is invasive. The drink test is noninvasive and may provide similar information. We evaluated relationships between drink test, gastric function, symptoms, and psychiatric distress. Controls (73) and functional dyspeptics (FD) (92) were studied using a 5-min water load test (WL5), gastric emptying, and electrogastrography (EGG). Symptoms, quality of life, and psychiatric distress were measured using standardized measures. Controls underwent test-retest of WL5 and comparison of WL5 with 100 ml/min water-based drink test (WL100) or nutrient drink. Controls, FD, and gastroparetics estimated drinking capacity before WL5 using a visual analog scale. WL5 correlated with WL100 (r = 0.7929) but not nutrient drink test (r = 0.1995). WL5 was significantly less in FD than controls, and abnormai WL5 was seen in 46%. In FD, volume to fullness inversely correlated with symptom severity (r = -0.29; P = 0.0154) and WL5 produced more symptoms, particularly nausea. Gastric function was not different between FD with normal or abnormal WL5. Symptoms and psychiatric distress were similar between normal and abnormal WL5 groups, but the abnormal group had significantly poorer quality of life. Controls and gastroparetics had good correlation of estimated and ingested volumes, but FD did not. Versus FD with normal WL5 capacity, FD with impaired drinking capacity have normal gastric function and similar symptoms but poorer quality of life. FD are less able to predict drinking capacity. These data suggest that WL5 identifies FD with intact gastric function but abnormal visceral perception. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Symptomatic gastroesophageal reflux disease (GERD), dyspepsia, and irritable bowel syndrome (IBS) are generally considered to be chronic conditions, but community- based studies are sparse, and long term natural history data are unavailable. We aimed to determine the natural history of these conditions. METHODS: A representative Swedish sample (20-79 yr) completed a validated questionnaire over the preceding 3 months. The survey was repeated after 1 and 7 yr in the same target group (n = 1290, 1260, and 1065; response rates 90%, 87%, and 82%, respectively: 79% responded to all three mailings). RESULTS: The prevalence of GERD symptoms remained stable, whereas the prevalence of IBS increased over time, independent of aging. Dyspepsia decreased with advancing age. Although more than half of those with IBS reported the same symptom profile after 1 and 7 yr, there was a substantial symptom fluctuation and symptom profile flux between those reporting dyspepsia, IBS, or minor symptoms. Only a minority with GERD (:lt;10%) changed to dyspepsia and/or IBS, or vice versa. The symptom-free patients remained symptom-free or reported only minor symptoms in ≥90% of cases. CONCLUSION: There seem to be two distinct populations of symptom reporters, those with dyspepsia or IBS, and those with GERD. [ABSTRACT FROM AUTHOR]

An abstract of the article "Bloating and Somatosensory Amplification in Functional Dyspepsia (FD)," by Michael P. Jones and Christine C. Ebert is presented.

INTRODUCTION: Wehypothesized that the prevalence of functional dyspepsia and gastroesophageal reflux disease in the community may be increasing. METHODS: Randomly selected adults were surveyed on 4 occasions: 1988 (n51,151, 21-79 years, response rate [rr] 5 90%), 1989 (n 5 1,097, 22-80 years, rr 5 87%), 1995 (n 5 1,139, 20-85 years, rr 5 76%), and 2011 (n 5 1,175, 20-93 years, rr 5 63%). RESULTS: In functional dyspepsia, the odds of postprandial distress syndrome tripled over 23 years' follow-up (odds ratio [OR]: 3.55; 95% confidence interval [CI]: 2.60-4.84, mixed-effect regression analysis), whereas a small decrease in epigastric pain syndrome was observed (OR: 0.65, 95% CI: 0.42-1.00). The odds of reporting gastroesophageal reflux disease doubled (OR: 2.02; 95% CI: 1.50-2.73). DISCUSSION: The underlying mechanisms behind the increase in postprandial distress syndrome and gastroesophageal reflux disease remain to be determined. [ABSTRACT FROM AUTHOR]