Characteristics of functional bowel disorder patients: a cross-sectional survey using the Rome III criteria

Food Hypersensitivity: Distinguishing Allergy from Intolerance, Main Characteristics, and Symptoms-A Narrative Review

Background/Objectives: Food hypersensitivity remains an understudied and overlooked subject globally. It is characterized by adverse reactions to dietary substances, potentially triggered by various mechanisms. Food allergy, a subset of food hypersensitivity, denotes an immune response to food proteins categorized into immunoglobulin IgE-mediated or non-IgE-mediated reactions. Conversely, food intolerance, another facet of food hypersensitivity, refers to non-immunological reactions, in which the human body cannot properly digest certain foods or components, leading to gastrointestinal discomfort and other non-immune-related symptoms. The main objective of this study was to determine and differentiate the differences, characteristics, and types of food hypersensitivity. Methods: This study involved a comprehensive review of key research from 1990 onward, including review articles, prospective studies, nested case-control studies, and meta-analyses. Results: Recognizing these differences is essential for healthcare professionals to ensure accurate diagnosis, effective management, and improved patient outcomes, while also aiding dietitians in providing optimal nutritional and dietary guidance. Conclusions: there are big differences between the main characteristics, such as symptoms, complications, and treatments between allergies, and food intolerances. Commonly reported trigger foods include cow milk, gluten, eggs, nuts, and seafood.

Rome Foundation Working Team Report on overlap in disorders of gut-brain interaction

In patients with disorders of gut-brain interaction (DGBI), overlapping non-gastrointestinal conditions such as fibromyalgia, headaches, gynaecological and urological conditions, sleep disturbances and fatigue are common, as is overlap among DGBI in different regions of the gastrointestinal tract. These overlaps strongly influence patient management and outcome. Shared pathophysiology could explain this scenario, but details are not fully understood. This overlap has been shown to be of great relevance for DGBI. In addition, symptoms considered to be caused by a DGBI could have a detectable organic cause, and in patients with a diagnosed organic gastrointestinal disease, symptoms not clearly explained by the pathology defining this organic disease are common. Thus, the aims of this Rome Foundation Working Team Report were to review the literature on overlapping conditions among patients with paediatric and adult DGBI and, based on the available epidemiological and clinical evidence, make recommendations for the current diagnostic and therapeutic approach, and for future research. Specifically, we focused on other DGBI in the same or different gastrointestinal anatomical region(s), DGBI overlap with organic bowel diseases in remission, and DGBI overlap with non-gastrointestinal, non-structural conditions.

Combined MRI, high-resolution manometry and a randomised trial of bisacodyl versus hyoscine show the significance of an enlarged colon in constipation: the RECLAIM study

BACKGROUND

Colonic motility in constipation can be assessed non-invasively using MRI.

OBJECTIVE

To compare MRI with high-resolution colonic manometry (HRCM) for predicting treatment response.

DESIGN

Part 1: 44 healthy volunteers (HVs), 43 patients with irritable bowel syndrome with constipation (IBS-C) and 37 with functional constipation (FC) completed stool diaries and questionnaires and underwent oral macrogol (500-1000 mL) challenge. Whole gut transit time (WGTT), segmental colonic volumes (CV), MRI-derived Motility Index and chyme movement by 'tagging' were assessed using MRI and time to defecation after macrogol recorded. Left colonic HRCM was recorded before and after a 700 kcal meal. Patients then proceeded to Part 2: a randomised cross-over study of 10-days bisacodyl 10 mg daily versus hyoscine 20 mg three times per day, assessing daily pain and constipation.

RESULTS

Part 1: Total CVs median (range) were significantly greater in IBS-C (776 (595-1033)) and FC (802 (633-951)) vs HV (645 (467-780)), p<0.001. Patients also had longer WGTT and delayed evacuation after macrogol. IBS-C patients showed significantly reduced tagging index and less propagated pressure wave (PPW) activity during HRCM versus HV. Compared with FC, IBS-C patients were more anxious and reported more pain. Abnormally large colons predicted significantly delayed evacuation after macrogol challenge (p<0.02), impaired manometric meal response and reduced pain with bisacodyl (p<0.05).Part 2: Bisacodyl compared with hyoscine increased bowel movements but caused more pain in both groups (p<0.03).

CONCLUSION

An abnormally large colon is an important feature in constipation which predicts impaired manometric response to feeding and treatment responses. HRCM shows that IBS-C patients have reduced PPW activity.

TRIAL REGISTRATION NUMBER

The study was preregistered on ClinicalTrials.gov, Reference: NCT03226145.

Impact of Enteric Nervous Cells on Irritable Bowel Syndrome: Potential Treatment Options

Irritable bowel syndrome (IBS) is a condition that significantly impacts the lifestyle, health, and habits of numerous individuals worldwide. Its diagnosis and classification are based on the Rome criteria, updated periodically to reflect new research findings in this field. IBS can be classified into different types based on symptoms, each with distinct treatment approaches and some differences in their pathophysiology. The exact pathological background of IBS remains unclear, with many aspects still unknown. Recent research developments suggest that disorders in the brain-gut-microbiota axis are key contributors to the symptoms and severity of IBS. The central nervous system (CNS) interacts bidirectionally with intestinal processes within the lumen and the intestinal wall, with the autonomic nervous system, particularly the vagus nerve, playing an important role. However, the enteric nervous system (ENS) is also crucial in the pathophysiological pathway of IBS. The apeline-corticotropin-releasing factor (CRF)-toll-like receptor 4 (TLR4) signaling route via enteric glia and serotonin production in enteroendocrine cells at the enteric barrier are among the most well-understood new findings that affect IBS through the ENS. Additionally, the microbiota regulates neuronal signals, modifying enteric function by altering the number of enteric bacteria and other mechanisms. Given the limited therapeutic options currently available, it is essential to identify new treatment targets, with the brain-gut axis, particularly the enteric nervous system, being a promising focus. This study aims to delineate the molecular mechanisms that induce IBS and to suggest potential targets for future research and treatment of this potentially debilitating disease.

Rifaximin and alternative agents in the management of irritable bowel syndrome: A comprehensive review

Rifaximin, a broad-spectrum antibiotic, boasts a unique chemical composition and pharmacokinetic profile, rendering it highly effective in treating irritable bowel syndrome (IBS). Its minimal systemic absorption confines its impact to the gastrointestinal (GI) tract, where it yields significant therapeutic benefits. This review examines rifaximin's physico-chemical attributes and its role in managing IBS symptoms. Its molecular structure facilitates intestinal lumen retention postoral administration, minimizing systemic exposure and adverse effects. This targeted action is crucial in addressing the gut microbiota's role in IBS pathophysiology. By modifying microbial populations and their metabolite production, rifaximin mitigates symptoms like bloating, irregular bowel habits, and abdominal pain associated with IBS. It achieves this by reducing pathogenic bacteria and altering bacterial metabolism, enhancing mucosal and immune function. Clinical trials affirm rifaximin's superiority over placebo and conventional therapies in alleviating overall IBS symptoms and addressing small intestine bacterial overgrowth (SIBO). Despite its promising efficacy and sustained symptom relief, further research is essential to optimize long-term effectiveness and dosing regimens. Rifaximin stands as a vital treatment option for IBS due to its distinctive properties and clinical utility; yet, ongoing investigation is imperative for maximizing its therapeutic benefits.

Constipation-associated factors in outpatients with schizophrenia: A multicenter questionnaire survey

Constipation is a prevalent gastrointestinal disorder that affects people globally, decreasing their quality of life and life expectancy. Individuals with schizophrenia often suffer from constipation, which could be a result of the illness itself or the side effects of psychotropic medications. However, little research has been conducted on factors contributing to constipation in individuals with schizophrenia. To address this issue, we conducted a survey using self-administered questionnaires and medical records to identify factors associated with constipation in psychiatric outpatients. This study included 399 patients with schizophrenia, resulting in a high prevalence of constipation (43.4%). The analysis suggested that female gender, the doses of antiparkinsonian medications, and benzodiazepine sleeping pills may be associated with constipation.

A meta-analysis of randomized controlled trials evaluating the effectiveness of fecal microbiota transplantation for patients with irritable bowel syndrome

OBJECTIVE

Multiple randomized controlled trials (RCTs) have investigated the efficacy of fecal microbiota transplantation (FMT) for irritable bowel syndrome (IBS), but have yielded inconsistent results. We updated the short-term and long-term efficacy of FMT in treating IBS, and performed a first-of-its-kind exploration of the relationship between gut microbiota and emotions.

METHODS

We conducted a comprehensive search of PubMed, Embase, Web of Science, and the Cochrane Library using various search strategies to identify all eligible studies. The inclusion criteria for data extraction were randomized controlled trials (RCTs) that investigated the efficacy of fecal microbiota transplantation (FMT) compared to placebo in adult patients (≥ 18 years old) with irritable bowel syndrome (IBS). A meta-analysis was then performed to assess the summary relative risk (RR) and corresponding 95% confidence intervals (CIs).

RESULTS

Out of 3,065 potentially relevant records, a total of 10 randomized controlled trials (RCTs) involving 573 subjects met the eligibility criteria for inclusion in the meta-analysis. The meta-analyses revealed no significant differences in short-term (12 weeks) (RR 0.20, 95% CI -0.04 to 0.44), long-term (52 weeks) global improvement (RR 1.38, 95% CI 0.87 to 2.21), besides short-term (12 weeks) (SMD - 48.16, 95% CI -102.13 to 5.81, I2 = 90%) and long-term (24 weeks) (SMD 2.16, 95% CI -60.52 to 64.83, I2 = 68%) IBS-SSS. There was statistically significant difference in short-term improvement of IBS-QoL (SMD 10.11, 95% CI 0.71 to 19.51, I2 = 82%), although there was a high risk of bias. In terms of long-term improvement (24 weeks and 54 weeks), there were no significant differences between the FMT and placebo groups (SMD 7.56, 95% CI 1.60 to 13.52, I2 = 0%; SMD 6.62, 95% CI -0.85 to 14.08, I2 = 0%). Sensitivity analysis indicated that there were visible significant effects observed when the criteria were based on Rome IV criteria (RR 16.48, 95% CI 7.22 to 37.62) and Gastroscopy (RR 3.25, 95%CI 2.37 to 4.47), Colonoscopy (RR 1.42, 95% CI 0.98 to 2.05). when using mixed stool FMT based on data from two RCTs, no significant difference was observed (RR 0.94, 95% CI 0.66 to -1.34). The remission of depression exhibited no significant difference between the FMT and placebo groups at the 12-week mark (SMD - 0.26, 95% CI -3.09 to 2.58), and at 24 weeks (SMD - 2.26, 95% CI -12.96 to 8.45). Furthermore, major adverse events associated with FMT were transient and self-limiting.

DISCUSSION

Based on the available randomized controlled trials (RCTs), the current evidence does not support the efficacy of FMT in improving global IBS symptoms in the long term. The differential results observed in subgroup analyses raise questions about the accurate identification of suitable populations for FMT. Further investigation is needed to better understand the reasons behind these inconsistent findings and to determine the true potential of FMT as a treatment for IBS.

Regulation of Pain Perception by Microbiota in Parkinson Disease

Pain perception involves current stimulation in peripheral nociceptive nerves and the subsequent stimulation of postsynaptic excitatory neurons in the spinal cord. Importantly, in chronic pain, the neural activity of both peripheral nociceptors and postsynaptic neurons in the central nervous system is influenced by several inflammatory mediators produced by the immune system. Growing evidence has indicated that the commensal microbiota plays an active role in regulating pain perception by either acting directly on nociceptors or indirectly through the modulation of the inflammatory activity on immune cells. This symbiotic relationship is mediated by soluble bacterial mediators or intrinsic structural components of bacteria that act on eukaryotic cells, including neurons, microglia, astrocytes, macrophages, T cells, enterochromaffin cells, and enteric glial cells. The molecular mechanisms involve bacterial molecules that act directly on neurons, affecting their excitability, or indirectly on non-neuronal cells, inducing changes in the production of proinflammatory or anti-inflammatory mediators. Importantly, Parkinson disease, a neurodegenerative and inflammatory disorder that affects mainly the dopaminergic neurons implicated in the control of voluntary movements, involves not only a motor decline but also nonmotor symptomatology, including chronic pain. Of note, several recent studies have shown that Parkinson disease involves a dysbiosis in the composition of the gut microbiota. In this review, we first summarize, integrate, and classify the molecular mechanisms implicated in the microbiota-mediated regulation of chronic pain. Second, we analyze the changes on the commensal microbiota associated to Parkinson disease and propose how these changes affect the development of chronic pain in this pathology. SIGNIFICANCE STATEMENT: The microbiota regulates chronic pain through the action of bacterial signals into two main locations: the peripheral nociceptors and the postsynaptic excitatory neurons in the spinal cord. The dysbiosis associated to Parkinson disease reveals increased representation of commensals that potentially exacerbate chronic pain and reduced levels of bacteria with beneficial effects on pain. This review encourages further research to better understand the signals involved in bacteria-bacteria and bacteria-host communication to get the clues for the development of probiotics with therapeutic potential.

Overlap of disorders of gut-brain interaction: a systematic review and meta-analysis

BACKGROUND

Rome criteria differentiate distinct types of disorders of gut-brain interaction (DGBI); also known as functional gastrointestinal disorders. Overlap of symptom categories frequently occurs. This systematic review and meta-analysis aimed to define the prevalence of DGBI overlap and compare overlap in population-based, primary care or tertiary care health settings. Furthermore, we aimed to compare symptom severity of psychological comorbidities in DGBI with and without overlap.

METHODS

For this systematic review and meta-analysis we searched MEDLINE (PubMed) and Embase electronic databases from inception until March 1, 2022, for original articles and conference abstracts of observational cross-sectional, case-controlled, or cohort design studies that reported the prevalence of DGBI overlap in adult participants (aged ≥18 years). We included only those studies where the diagnosis of DGBI was based on clinical assessment, questionnaire data, or specific symptom-based criteria. Studies were excluded if reporting on mixed populations of DGBI and organic diseases. Aggregate patient data were extracted from eligible published studies. The prevalence of DGBI overlap in all studies was pooled using the DerSimonian and Laird random effects model, and further analysis stratified by subgroups (care setting, diagnostic criteria, geographic region, and gross domestic product per capita). We also assessed the relationship between DGBI overlap with anxiety, depression, and quality of life symptom scores. This study was registered with PROSPERO (CRD42022311101).

FINDINGS

46 of 1268 screened studies, reporting on 75 682 adult DGBI participants, were eligible for inclusion in this systematic review and meta-analysis. Overall, 24 424 (pooled prevalence 36·5% [95% CI 30·7 to 42·6]) participants had a DGBI overlap, with considerable between-study heterogeneity (I2=99·51, p=0·0001). In the tertiary health-care setting, overlap among participants with DGBI was more prevalent (8373 of 22 617, pooled prevalence 47·3% [95% CI 33·2 to 61·7]) compared with population-based cohorts (11 332 of 39 749, pooled prevalence 26·5% [95% CI 20·5 to 33·4]; odds ratio 2·50 [95% CI 1·28 to 4·87]; p=0·0084). Quality of life physical component scores were significantly lower in participants with DGBI overlap compared with participants without overlap (standardised mean difference -0·47 [95% CI -0·80 to -0·14]; p=0·025). Participants with DGBI overlap had both increased symptom scores for anxiety (0·39 [95% CI 0·24 to 0·54]; p=0·0001) and depression (0·41 [0·30 to 0·51]; p=0·0001).

INTERPRETATION

Overlap of DGBI subtypes is frequent, and is more prevalent in tertiary care settings and associated with more severe symptom manifestations or psychological comorbidities. Despite the large sample size, the comparative analyses revealed substantial heterogeneity, and the results should be interpreted with caution.

FUNDING

National Health and Medical Research Council and Centre for Research Excellence.

GI factors, potential to predict prostate motion during radiotherapy; a scoping review

Purpose

A scoping literature review was conducted to identify gastrointestinal (GI) factors most likely to influence prostate motion during radiotherapy. We proffer that patient specific measurement of these GI factors could predict motion uncertainty during radiotherapy, facilitating personalised care by optimising treatment technique e.g., daily adaption or via bespoke patient pre-habilitation and preparation.

Methods

The scoping review was undertaken as per JBI guidelines. Searches were conducted across four databases: Ovid Medline®, EMBASE, CINAHL and EBSCO discovery. Articles written in English from 2010-present were included. Those pertaining to paediatrics, biological women exclusively, infectious and post-treatment GI morbidity and diet were excluded.Common GI factors impacting men were identified and related symptoms, incidence and measurement tools examined. Prevalence among persons with prostate cancer was explored and suitable assessment tools discussed.

Results

A preliminary search identified four prominent GI-factors: mental health, co-morbidity and medication, physical activity, and pelvic floor disorder. The scoping search found 3644 articles; 1646 were removed as duplicates. A further 1249 were excluded after title and abstract screening, 162 remained subsequent to full text review: 42 mental health, 53 co-morbidity and medication, 39 physical activity and 28 pelvic floor disorder.Six GI factors prevalent in the prostate cancer population and estimated most likely to influence prostate motion were identified: depression, anxiety, diabetes, obesity, low physical activity, and pelvic floor disorder. Reliable, quick, and easy to use tools are available to quantify these factors.

Conclusion

A comprehensive GI factor assessment package suitable to implement into the radiotherapy clinic has been created. Unveiling these GI factors upfront will guide improved personalisation of radiotherapy.

A systematic review, pairwise meta-analysis and network meta-analysis of randomized controlled trials exploring the role of fecal microbiota transplantation in irritable bowel syndrome

BACKGROUND

Treatment is a challenge in Irritable Bowel Syndrome (IBS) and fecal microbiota transplantation (FMT) has attracted significant interest. Network meta-analysis (NWM) has been established as an evidence-synthesis tool that incorporates direct and indirect evidence in a collection of randomized controlled trials (RCTs) comparing therapeutic intervention competing for similar therapeutic results. No NWM exists concerning the comparative effectiveness and safety of various FMT modalities for IBS.

AIM

We updated pairwise meta-analyses published in the past and assessed the comparative effectiveness and safety of various FMT delivery modalities for IBS.

METHODS

Pairwise meta-analyses and Bayesian NWM were performed. Heterogeneity, consistency of results and publication bias were explored.

RESULTS

Of 510 titles raised by initial search, seven RCTs were entered into meta-analyses and NWM. They included 470 patients and controls, in whom four FMT delivery modalities were used, that is via colonoscopy, nasojejunal tube, duodenoscope and capsules per os. In the pairwise meta-analysis, the pooled results showed that overall FMT was not superior to placebo, whereas the subgroup analyses showed that FMT via duodenoscope and nasojejunal tube was superior. The NWM showed that 60-g FMT via duodenoscope had the highest efficacy (OR, 26.38; 95% CI, 9.22-75.51) and was by far the highest in the efficacy ranking (SUCRA, 98.8%).

CONCLUSION

The pooled results showed no overall advantage of FMT over placebo in IBS. However, upper GI delivery (via duodenoscopy or nasojejunal tube) proved to be effective. Consequently, well-designed RCTs are needed to ensure the efficacy and safety profile before FMT can be applied in everyday clinical practice for IBS patients.

Functional bowel disorders with diarrhoea: Clinical guidelines of the United European Gastroenterology and European Society for Neurogastroenterology and Motility

Irritable bowel syndrome with diarrhoea (IBS-D) and functional diarrhoea (FDr) are the two major functional bowel disorders characterized by diarrhoea. In spite of their high prevalence, IBS-D and FDr are associated with major uncertainties, especially regarding their optimal diagnostic work-up and management. A Delphi consensus was performed with experts from 10 European countries who conducted a literature summary and voting process on 31 statements. Quality of evidence was evaluated using the grading of recommendations, assessment, development, and evaluation criteria. Consensus (defined as >80% agreement) was reached for all the statements. The panel agreed with the potential overlapping of IBS-D and FDr. In terms of diagnosis, the consensus supports a symptom-based approach also with the exclusion of alarm symptoms, recommending the evaluation of full blood count, C-reactive protein, serology for coeliac disease, and faecal calprotectin, and consideration of diagnosing bile acid diarrhoea. Colonoscopy with random biopsies in both the right and left colon is recommended in patients older than 50 years and in presence of alarm features. Regarding treatment, a strong consensus was achieved for the use of a diet low fermentable oligo-, di-, monosaccharides and polyols, gut-directed psychological therapies, rifaximin, loperamide, and eluxadoline. A weak or conditional recommendation was achieved for antispasmodics, probiotics, tryciclic antidepressants, bile acid sequestrants, 5-hydroxytryptamine-3 antagonists (i.e. alosetron, ondansetron, or ramosetron). A multinational group of European experts summarized the current state of consensus on the definition, diagnosis, and management of IBS-D and FDr.

Characteristics of, and natural history among, individuals with Rome IV functional bowel disorders

BACKGROUND

Little is known about the natural history of functional bowel disorders using Rome IV criteria. We examined these issues in a longitudinal follow-up study.

METHODS

We collected complete demographic, gastrointestinal symptom, and psychological comorbidity data at baseline from 1372 adults who met Rome IV criteria for one of the five functional bowel disorders. At 12 months, we collected data regarding gastrointestinal symptoms, psychological comorbidity, consultation behavior, and treatment commenced. We examined prognosis and stability of all five functional bowel disorders.

KEY RESULTS

At baseline, 811 (59.1%) individuals met Rome IV criteria for irritable bowel syndrome (IBS), 76 (5.5%) functional constipation (FC), 199 (14.5%) functional diarrhea (FDr), 130 (9.5%) functional abdominal bloating or distension (FABD), and 156 (11.4%) unspecified functional bowel disorder (UFBD). In total, 782 (57.0%) were successfully followed up. Individuals with IBS at baseline were significantly more likely to report symptoms compatible with anxiety, depression, or somatoform-type behavior (p < 0.001 for all analyses) at baseline and follow-up compared with those with the other four functional bowel disorders. IBS was the most stable functional bowel disorder; 319 (70.6%) of 452 participants still met criteria for IBS at 12 months, compared with 14 (34.1%) of 41, 43 (35.5%) of 121, 26 (33.8%) of 77, and 37 (40.7%) of 91 for FC, FDr, FABD, and UFBD, respectively (p < 0.001).

CONCLUSIONS AND INFERENCES

Individuals with Rome IV-defined IBS exhibited higher levels of anxiety, depression, or somatoform-type symptom reporting. IBS was the most stable and the likeliest disorder that the other four functional bowel disorders would fluctuate to.

Efficacy of Fecal Microbiota Transplantation in Irritable Bowel Syndrome Patients: An Updated Systematic Review and Meta-Analysis

Irritable bowel syndrome (IBS) is a chronic gastrointestinal disease characterized by abdominal discomfort and bloating, diarrhea, and/or constipation. Fecal microbiota transplantation (FMT) is transferring the fecal bacteria and other microorganisms from a healthy person to another. We performed this systematic review and meta-analysis to assess the efficacy of FMT in treating IBS patients. We searched Scopus, PubMed, Cochrane, and Web of Science databases through June 2021 using relevant key words. We included 19 studies. Fecal microbiota transplantation was significantly superior to placebo in IBS quality of life after 4 weeks (mean difference [MD] = 7.47, 95% confidence interval [CI]: 2.05-12.89, p = .04), 12 weeks (MD = 9.99, 95% CI: 5.78-14.19, p < .00001), and 24 weeks (MD = 8.49, 95% CI: 0.47-16.52, p = .04), with no difference regarding IBS improvement symptoms and the IBS Severity Scoring System (SSS). Single-arm analysis revealed that the incidence of improvement of IBS symptoms was 57.8% (45.6%-69.9%) with reduction in IBS-SSS (MD = -74, 95% CI: -101.7 to -46.3). Fecal microbiota transplantation was superior to placebo in improving quality of life after 4, 12, and 24 weeks. Also, FMT improved IBS symptoms and reduced the IBS-SSS score. However, no deference was detected between FMT and placebo in IBS-SSS score and IBS symptoms improvement.

Understanding the physiology of human defaecation and disorders of continence and evacuation

The act of defaecation, although a ubiquitous human experience, requires the coordinated actions of the anorectum and colon, pelvic floor musculature, and the enteric, peripheral and central nervous systems. Defaecation is best appreciated through the description of four phases, which are, temporally and physiologically, reasonably discrete. However, given the complexity of this process, it is unsurprising that disorders of defaecation are both common and problematic; almost everyone will experience constipation at some time in their life and many will develop faecal incontinence. A detailed understanding of the normal physiology of defaecation and continence is critical to inform management of disorders of defaecation. During the past decade, there have been major advances in the investigative tools used to assess colonic and anorectal function. This Review details the current understanding of defaecation and continence. This includes an overview of the relevant anatomy and physiology, a description of the four phases of defaecation, and factors influencing defaecation (demographics, stool frequency/consistency, psychobehavioural factors, posture, circadian rhythm, dietary intake and medications). A summary of the known pathophysiology of defaecation disorders including constipation, faecal incontinence and irritable bowel syndrome is also included, as well as considerations for further research in this field.

Increased psychological distress and somatization in patients with irritable bowel syndrome compared with functional diarrhea or functional constipation, based on Rome IV criteria

BACKGROUND

The Rome IV criteria for disorders of gut-brain interaction define irritable bowel syndrome (IBS) as a functional bowel disorder associated with frequent abdominal pain of at least 1 day per week. In contrast, functional diarrhea (FD) and functional constipation (FC) are relatively painless. We compared differences in mood and somatization between Rome IV IBS and FC/FD.

METHODS

A total of 567 patients with Rome IV defined IBS or FD/FC completed a baseline questionnaire on demographics, abdominal pain frequency, mood (hospital anxiety and depression scale, HADS), and somatization (patient health questionnaire, PHQ-12). The primary analysis compared differences in mood and somatization between IBS and FC/FD, and the relative influence of abdominal pain frequency on these extra-intestinal symptoms. The secondary analysis evaluated differences across individual IBS subtypes, and also between FC and FD.

KEY RESULTS

Patients with IBS-in comparison to those with FC/FD-had significantly higher mean PHQ-12 somatization scores (9.1 vs. 5.4), more somatic symptoms (6.0 vs. 4.3), abnormally high somatization levels (16% vs. 3%), higher HADS score (15.0 vs. 11.7), and clinically abnormal levels of anxiety (38% vs. 20%) and depression (17% vs. 10%). Increasing abdominal pain frequency correlated positively with PHQ-12, number of somatic symptoms, and HADS; p < 0.001. No differences in mood and somatization scores were seen between individual IBS subtypes, and nor between FC and FD.

CONCLUSION & INFERENCES

Based on the Rome IV criteria, IBS is associated with increased levels of psychological distress and somatization compared with FD or FC. Patients reporting frequent abdominal pain should be comprehensively screened for psychosomatic disorders, with psychological therapies considered early in the disease course.

Complementary and Alternative Medicine Therapies for Irritable Bowel Syndrome

Complementary and alternative medicine (CAM) is a term used to define a broad range of therapies, most commonly grouped into natural products, mind-body medicine, and traditional systems of medicine. Patients with irritable bowel syndrome (IBS) commonly use CAM therapies, although there are many barriers that may keep patients and providers from talking about a patient's CAM use. Despite limited quantity and quality of evidence of CAM for IBS, providers can better counsel patients on CAM use by understanding pitfalls related to CAM use and by learning what is known about CAM.

Global prevalence of functional constipation according to the Rome criteria: a systematic review and meta-analysis

BACKGROUND

Functional constipation is a common functional bowel disorder in the community, which has a varying prevalence across cross-sectional surveys. We did a contemporaneous systematic review and meta-analysis of studies using comparable methodology and all iterations of the Rome criteria to estimate the global prevalence of functional constipation.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE, Embase, and Embase Classic from Jan 1, 1990, to Dec 31, 2020, to identify population-based cross-sectional studies comprising at least 50 participants that reported the prevalence of functional constipation in adults (age 18 years and older) according to Rome I, II, III, or IV criteria. We excluded studies that reported the prevalence of functional constipation in convenience samples. We extracted prevalence estimates of functional constipation from eligible studies, according to the study criteria used to define it. For each study, we extracted data for country; method of data collection; criteria used to define functional constipation; whether the study used the Rome I, II, III, or IV diagnostic questionnaires or approximated these definitions of the condition using another questionnaire; the total number of participants providing complete data; age; the number of participants with the condition; the number of male and female participants; and the number of male and female participants with the condition. We calculated pooled prevalence, odds ratios (OR), and 95% CIs.

FINDINGS

Of 8174 citations evaluated, 45 studies fulfilled the eligibility criteria, representing 80 separate populations and comprising 275 260 participants. The pooled prevalence of functional constipation was 15·3% (95% CI 8·1-24·4, I2=99·4%) in studies using the Rome I criteria, 11·2% (7·9-14·9; I2=99·6%) in studies that used Rome II criteria, 10·4% (6·5-14·9; I2=99·8%) in those that used Rome III criteria, and 10·1% (8·7-11·6; I2=98·2%) when Rome IV criteria were used. Prevalence of functional constipation was higher in women, irrespective of the Rome criteria used (OR 2·40 [95% CI 2·02-2·86] for Rome I, 1·94 [1·46-2·57] for Rome II, and 2·32 [1·85-2·92] for Rome III; no studies using Rome IV criteria reported prevalence by sex). There was significant heterogeneity between studies in all of our analyses, which persisted even when the same criteria were applied and similar methodologies used.

INTERPRETATION

Even when uniform symptom-based criteria are used to define the presence of functional constipation, prevalence varies between countries. Thus, environmental, cultural, ethnic, dietary, or genetic factors can influence reporting of symptoms. Future studies should aim to elucidate reasons for this geographical variability.

FUNDING

None.

British Society of Gastroenterology guidelines on the management of irritable bowel syndrome

Irritable bowel syndrome (IBS) remains one of the most common gastrointestinal disorders seen by clinicians in both primary and secondary care. Since publication of the last British Society of Gastroenterology (BSG) guideline in 2007, substantial advances have been made in understanding its complex pathophysiology, resulting in its re-classification as a disorder of gut-brain interaction, rather than a functional gastrointestinal disorder. Moreover, there has been a considerable amount of new evidence published concerning the diagnosis, investigation and management of IBS. The primary aim of this guideline, commissioned by the BSG, is to review and summarise the current evidence to inform and guide clinical practice, by providing a practical framework for evidence-based management of patients. One of the strengths of this guideline is that the recommendations for treatment are based on evidence derived from a comprehensive search of the medical literature, which was used to inform an update of a series of trial-based and network meta-analyses assessing the efficacy of dietary, pharmacological and psychological therapies in treating IBS. Specific recommendations have been made according to the Grading of Recommendations Assessment, Development and Evaluation system, summarising both the strength of the recommendations and the overall quality of evidence. Finally, this guideline identifies novel treatments that are in development, as well as highlighting areas of unmet need for future research.

Chronic constipation in adults: Contemporary perspectives and clinical challenges. 1: Epidemiology, diagnosis, clinical associations, pathophysiology and investigation

BACKGROUND

Chronic constipation is a prevalent disorder that affects patients' quality of life and consumes resources in healthcare systems worldwide. In clinical practice, it is still considered a challenge as clinicians frequently are unsure as to which treatments to use and when. Over a decade ago, a Neurogastroenterology & Motility journal supplement devoted to the investigation and management of constipation was published (2009; 21 (Suppl.2)). This included seven articles, disseminating all themes covered during a preceding 2-day meeting held in London, entitled "Current perspectives in chronic constipation: a scientific and clinical symposium." In October 2018, the 3rd London Masterclass, entitled "Contemporary management of constipation" was held, again over 2 days. All faculty members were invited to author two new review articles, which represent a collective synthesis of talks presented and discussions held during this meeting.

PURPOSE

This article represents the first of these reviews, addressing epidemiology, diagnosis, clinical associations, pathophysiology, and investigation. Clearly, not all aspects of the condition can be covered in adequate detail; hence, there is a focus on particular "hot topics" and themes that are of contemporary interest. The second review addresses management of chronic constipation, covering behavioral, conservative, medical, and surgical therapies.

The relationship between gut microbiota and proteolytic activity in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disease that affects 3.8-9.2% of the world population. It affects the physiology and psychology of patients and increases the burden on families, the healthcare system, society, and economic development. Presently, a large number of studies have shown that compared to healthy individuals, the composition and diversity of gut microbiota in IBS patients have changed, and the proteolytic activity (PA) in fecal supernatant and colonic mucosa of IBS patients has also increased. These findings indicate that the imbalance of intestinal microecology and intestinal protein hydrolysis is closely related to IBS. Furthermore, the intestinal flora is a key substance that regulates the PA and is associated with IBS. The current review described the intestinal microecology and intestinal proteolytic activity of patients with IBS and also discussed the effect of intestinal flora on PA. In summary, this study proposed a pivotal role of gut microbiota and PA in IBS, respectively, and provided an in-depth insight into the diagnosis and treatment targets of IBS as well as the formulation of new treatment strategies for other digestive diseases and protease-related diseases.

The level and prevalence of depression and anxiety among patients with different subtypes of irritable bowel syndrome: a network meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is a very common functional bowel disorder. However, the difference of depression and anxiety comorbidities among different IBS subtypes is still not well evaluated. This study aims to investigate the difference in the level and prevalence of depression and anxiety among healthy controls and patients with different subtypes of IBS.

METHODS

PubMed, EMBASE and the Cochrane library were searched systematically until August 17, 2020. Studies that investigated depression and/or anxiety levels or prevalence among different IBS-subtype patients measured at baseline or the same point were included. Network meta-analysis was conducted to analyze standardized mean difference (SMD) of anxiety and depression levels, and single arm meta-analysis was performed for prevalence of anxiety and depression among different IBS subtypes.

RESULTS

Eighteen studies involving 7095 participants were included. Network meta-analyses results showed healthy controls had a lower level of depression than IBS with mixed symptoms of constipation and diarrhea (IBS-M) [SMD =  - 1.57; 95% confidence interval (CI) - 2.21,  - 0.92], IBS with constipation (IBS-C) (SMD =  - 1.53; 95% CI - 2.13,  - 0.93) and IBS with diarrhea (IBS-D)(SMD =  - 1.41; 95% CI - 1.97,  - 0.85), while no significant difference was found between IBS unclassified (IBS-U) and healthy controls (SMD =  - 0.58; 95% CI  - 2.15, 1.00). There was also no significant difference in the level of depression among different IBS subtypes patients. The results of anxiety were similar to depression. Ranking probability showed that IBS-M was associated with the highest level of depression and anxiety symptoms, followed by IBS-C/IBS-D and IBS-U. Single-arm meta-analysis showed IBS-C had the highest prevalence of depression (38%) and anxiety (40%), followed by IBS-D, IBS-M and IBS-U.

CONCLUSION

The results indicated that IBS-M was more likely to be associated with a higher level of depression and anxiety, and the prevalence of depression and anxiety in IBS-C was highest. The psychological screening and appropriate psychotherapy are needed for patients with IBS-C, IBS-D and IBS-M instead of IBS-U.

A systematic review and meta-analysis of biofeedback therapy for dyssynergic defaecation in adults

BACKGROUND

Dyssynergic defaecation is a common form of functional constipation that responds poorly to conservative interventions. This systematic review and meta-analysis assesses the effectiveness of biofeedback therapy for dyssynergic defaecation using global clinical improvement as the primary outcome, and resolution of the dyssynergic pattern on anorectal physiology and quality of life as secondary outcomes.

METHODS

MEDLINE, EMBASE, CENTRAL, PsychInfo, CINAHL, Scopus, and Web of Science were searched from inception to March 2019 using a predefined strategy. Randomised controlled trials of adult patients with dyssynergic defaecation and a biofeedback treatment arm were eligible for review. Studies including patients with secondary forms of constipation were excluded. Data abstraction and risk of bias assessments were conducted by consensus between two authors.

RESULTS

Eleven trials including 725 participants were included in the narrative review. Sixty-three percent of patients treated with biofeedback reported clinical improvement. Six studies included in the meta-analysis showed biofeedback superior to non-biofeedback therapy for the primary outcome (OR 3.63, CI 1.10-11.93, p = 0.03). Heterogeneity between trials and overall risk of bias was high.

CONCLUSIONS

Biofeedback therapy is recommended for patients referred to tertiary units with dyssynergic defaecation who fail conservative therapy. Future research should be directed towards identifying validated outcomes and the optimum method for delivering biofeedback therapy. Home biofeedback therapy may improve accessibility and recruitment to future clinical trials.

Bimodal Release Ondansetron Improves Stool Consistency and Symptomatology in Diarrhea-Predominant Irritable Bowel Syndrome: A Randomized, Double-Blind, Trial

INTRODUCTION

Previous, small studies have suggested that ondansetron has beneficial effects in diarrhea-predominant irritable bowel syndrome (IBS-D). This randomized, double-blind study evaluated the efficacy and safety of daily 12 mg RHB-102, an investigational bimodal release ondansetron tablet, in IBS-D.

METHODS

Men and women with IBS-D by the Rome III criteria, Bristol Stool Scale ≥6 on 2 or more days weekly, and average daily worst pain intensity ≥3/10 were randomized 60:40 to RHB-102 or placebo once daily for 8 weeks. The primary end point was overall stool consistency response for at least 4 of 8 weeks. Secondary end points included overall worst abdominal pain and overall composite response, defined as response on both abdominal pain and stool consistency end points.

RESULTS

Overall stool consistency response rates were 56.0% and 35.3% (RHB-102 vs placebo, P = 0.036) and similar among male and female patients. Overall pain response (50.7% vs 39.2%) and composite response rates (40.0% vs 25.5%) favored RHB-102, although these differences were not statistically significant. Stool consistency response rates were enhanced in patients with baseline C-reactive protein above the median (2.09 mg/L), 59.5%, vs 23.1% (P = 0.009). Overall rates of adverse events were similar, with a higher rate of constipation in RHB-102 patients (13.3% vs 3.9%) that resolved rapidly on withholding treatment.

DISCUSSION

RHB-102 was effective and safe in the treatment of men and women with IBS-D. Baseline C-reactive protein seemed to be predictive of response.

Chronic constipation and abdominal pain: Independent or closely interrelated symptoms?

Constipation is both a symptom and a disorder, seen in both functional constipation and irritable bowel syndrome with constipation predominance (IBS-C). Despite the Rome IV criteria distinguishing between these conditions, they share many therapeutic approaches. This review aims to explore the relationship between constipation and abdominal pain and assess the evidence surrounding whether laxation improves abdominal pain and whether such a response to laxation differs between IBS-C and functional constipation. In patients with functional constipation, increasing frequency of bowel motions by laxatives regardless of mechanism of action is associated with reductions in the severity of abdominal pain, supporting the role of constipation as a contributor to abdominal discomfort. In patients with IBS-C, evidence from systematic reviews indicates that abdominal pain is driven by factors additional to constipation alone and that visceral analgesic modulation is also needed to optimize pain. Changing definitions of IBS-C and heterogeneity in clinical trial design including endpoints have raised uncertainty about the comparative ability of older laxatives without known neuromodulatory effects to improve chronic abdominal pain compared with new secretagogues and prokinetics for the management of IBS-C. While it is known that abdominal pain is associated with constipation and laxation contributes to relief of that pain, it remains unproven whether proposed visceral analgesic properties of new laxatives provide greater pain relief than laxation alone. However, it is likely that the response to laxation in IBS-C is only part of the puzzle.

Irritable Bowel Syndrome: News from an Old Disorder

Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder, which can affect all members of a society, regardless of age, sex, race or socioeconomic status. Because of its high prevalence and chronic nature, it represents a significant economic burden. In fact, these patients have a relevant impairment of their quality of life, which limits their work productivity and daily social activities, especially when it is associated with other disorders, such as anxiety and depression. The diagnosis of IBS relies on symptom-based diagnostic criteria with normal results on a limited number of complementary tests that rule out other possible diagnoses. The aetiology of this condition is incompletely established. However, evidence suggests that it is a multifactorial disorder with several different mechanisms that have been implicated as responsible for the symptoms. Since the treatment strategy is usually based on predominant symptoms and their severity, it is important to recognise the underlying mechanisms in order to successfully relief the visceral pain and altered bowel habits. The aim of this non-systematic review of the literature was to explore the pathophysiology and treatment options of IBS, highlighting the most recent evidence, from the new Rome IV criteria to the new drug armamentarium.

Similarities in Clinical and Psychosocial Characteristics of Functional Diarrhea and Irritable Bowel Syndrome With Diarrhea

BACKGROUND & AIMS

There have been few published studies of clinical and psychological characteristics of patients with functional diarrhea (FDr). We studied the clinical and psychological characteristics of patients with FDr presenting to a tertiary care clinic, and compared symptom profiles of FDr with those of IBS-diarrhea (IBS-D).

METHODS

Consecutive patients with a diagnosis of FDr (n = 48) or IBS-D (n = 49), per Rome IV criteria, completed a detailed symptom survey from October 2017 through July 2018. Abdominal pain and diarrhea severity were assessed using patient-reported outcomes measurement information system (PROMIS) questionnaires. Patients with anxiety, depression, or sleep disturbances were identified based on PROMIS T-score of 60 or more. Mean and proportions were compared using the Student t test and chi-square analyses, respectively.

RESULTS

A significantly lower proportion of patients with FDr reported abdominal pain (77.1%) than patients with IBS-D (100%, P < .001). The proportion of patients reporting abdominal bloating and level of severity did not differ significantly between groups. Proportions of bowel movements with diarrhea did not differ significantly between groups (P = .54), but the mean diarrhea PROMIS T-score was significantly higher among patients with IBS-D (P = .03). This difference resulted from the significantly higher levels of fecal urgency-related distress reported by patients with IBS-D (P = .007). Proportions of patients with anxiety, depression, or sleep disturbance, and their severities, did not differ significantly between groups.

CONCLUSIONS

In an analysis of about 100 patients with FDr or IBS-D, we found overlap in gastrointestinal and psychosomatic symptoms. These 2 entities appear to be a continuum.

Comparative efficacy of pharmacological and nonpharmacological treatments for chronic idiopathic constipation in China: a Bayesian network meta-analysis

BACKGROUND

To provide evidence for medical management of chronic idiopathic constipation (CIC) in China based on comparisons of all clinical practical interventions using Bayesian network meta-analysis.

METHODS

We conducted a systematic literature review by searching PubMed, Embase, Cochrane Central, the China National Knowledge Infrastructure (CNKI), and the Wanfang Database (inception to May 2019) for randomized controlled trials (RCTs) for CIC in Chinese people. Only RCTs that recruited participants aged over 18 and diagnosed with CIC by the Rome II, III or IV criteria were included. We used three outcomes to examine efficacy. The risk ratio (RR) of the responder rate, based on ≥3 spontaneous bowel movements (SBMs) per week after treatment, was the primary outcome, and the SBM count per week and the Bristol score (BS) were secondary outcomes. In addition, adverse effects (AEs) were also considered a secondary outcome to evaluate safety. We conducted Bayesian network meta-analysis with random effects, and the RR or mean difference with its 95% credible interval was calculated. In addition, we ranked all treatments via their cumulative curves (SUCRA) and assessed the quality of evidence according to the GRADE criteria.

RESULTS

We included a total of 42 trials (6820 participants) of 20 grouped interventions that included pharmacological and nonpharmacological treatments. For the primary outcome, fourteen interventions were significantly better than placebo, and Probiotics plus Mosapride (PB + MP) appeared superior to others (GRADE quality of evidence: Moderate to Low), followed by Prucalopride (PP) (High to Low) and Electroacupuncture (EA) (High to Low). For SBM, Compound sodium bicarbonate suppository (CSBS) appeared to be best, with an SUCRA value of 90% (High to Low). For BS, Lactulose plus Probiotics (LT + PB) was superior to others (Moderate to Low), followed by Polyethylene glycol (PEG) (High to Moderate). Although all interventions appeared non-significant when compared with placebo in terms of adverse effects, Lactulose plus Mosapride showed greater risk than others on ranking probability.

CONCLUSIONS

Given the GRADE assessment, PB + MP, PP and EA may be the priory options with moderate certainty in the quality of evidence for the primary outcome. For SBM, a CSBS may be the best option with moderate certainty in the quality of evidence. For BS, PEG may be the priory option with high certainty in the quality of evidence. However, due to a lack of high certainty in the quality of evidence, caution is needed when recommending the interventions. Because of the limitations, an increased number of trials are required for more accurate results.

Systematic review with meta-analysis: the prevalence of anxiety and depression in patients with irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a common and potential disabling functional gastrointestinal disorder. Studies have revealed a possible association between IBS and psychological problems, such as anxiety and depression. Existing systematic reviews have addressed only the levels of anxiety or depression in patients with IBS.

AIM

To investigate systematically the prevalence of anxiety or depression in IBS patients METHODS: A literature search was conducted using the related keywords from the bibliographic databases of Embase, PubMed, Scopus, Web of Science and POPLINE published until 1 January 2019 with no language restriction. Studies reporting the prevalence of anxiety/depressive symptoms/disorders in adult (≥15 years) IBS patients were evaluated. The pooled prevalence, odds ratio (OR) and 95% CI were calculated using stata software.

RESULTS

A total of 14 926 articles were initially screened, and finally 73 papers were included. The prevalence rates of anxiety symptoms and disorders in IBS patients were 39.1% (95% CI: 32.4-45.8) and 23% (95% CI: 17.2-28.8) respectively. The ORs for anxiety symptoms and disorders in IBS patients compared with healthy subjects were 3.11 (95% CI: 2.43-3.98) and 2.52 (95% CI: 1.99-3.20) respectively. The prevalence estimates of depressive symptoms and disorders in IBS patients were 28.8% (95% CI: 23.6-34) and 23.3% (95% CI: 17.2-29.4) respectively. The ORs for depressive symptoms and disorders in IBS patients compared to healthy subjects were 3.04 (95% CI: 2.37-3.91) and 2.72 (95% CI: 2.45-3.02) respectively.

CONCLUSION

Patients with IBS have a three-fold increased odds of either anxiety or depression, compared to healthy subjects.

Efficacy of Fecal Microbiota Transplantation in Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis

OBJECTIVES

Irritable bowel syndrome (IBS) is a common gastrointestinal condition with a heterogeneous pathophysiology. An altered gut microbiome has been identified in some IBS patients, and fecal microbiota transplantation (FMT) has been suggested to treat IBS. We performed meta-analyses and systematic review of available randomized controlled trials (RCTs) to evaluate the efficacy of FMT in IBS.

METHODS

We performed a systematic literature search of MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Web of Science. Selection criteria included RCTs of FMT vs placebo using FMT excipients or autologous FMT in IBS. Meta-analyses were conducted to evaluate the summary relative risk (RR) and 95% confidence intervals (CIs) of combined studies for primary outcome of improvement in global IBS symptoms as measured by accepted integrative symptom questionnaires or dichotomous responses to questions of overall symptom improvement.

RESULTS

Among 742 citations identified, 7 were deemed to be potentially relevant, of which 4 studies involving 254 participants met eligibility. No significant difference in global improvement of IBS symptoms was observed at 12 weeks in FMT vs placebo (RR = 0.93; 95% CI 0.48-1.79). Heterogeneity among studies was significant (I = 79%). Subgroup analyses revealed benefits of single-dose FMT using colonoscopy and nasojejunal tubes in comparison with autologous FMT for placebo treatment (number needed to treat = 5, RR = 1.59; 95% CI 1.06-2.39; I = 0%) and a reduction in likelihood of improvement of multiple-dose capsule FMT RCTs (number needed to harm = 3, RR = 0.54; 95% CI 0.34-0.85; I = 13%). Placebo response was 33.7% in nonoral FMT RCTs and 67.8% in capsule FMT RCTs. The Grading of Recommendations Assessment, Development and Evaluation quality of the body of evidence was very low.

DISCUSSION

Current evidence from RCTs does not suggest a benefit of FMT for global IBS symptoms. There remain questions regarding the efficacy of FMT in IBS as well as the lack of a clean explanation on the discrepant results among RCTs in subgroup analyses.

Chronic idiopathic constipation in adults: epidemiology, pathophysiology, diagnosis and clinical management

Chronic idiopathic constipation (CIC) is one of the most common gastrointestinal disorders, with a global prevalence of 14%. It is commoner in women and its prevalence increases with age. There are three subtypes of CIC: dyssynergic defaecation, slow transit constipation and normal transit constipation, which is the most common subtype. Clinical assessment of the patient with constipation requires careful history taking, in order to identify any red flag symptoms that would necessitate further investigation with colonoscopy to exclude colorectal malignancy. Screening for hypercalcaemia, hypothyroidism and coeliac disease with appropriate blood tests should be considered. A digital rectal examination should be performed to assess for evidence of dyssynergic defaecation. If this is suspected, further investigation with high resolution anorectal manometry should be undertaken. Anorectal biofeedback can be offered to patients with dyssynergic defaecation as a means of correcting the associated impairment of pelvic floor, abdominal wall and rectal functioning. Lifestyle modifications, such as increasing dietary fibre, are the first step in managing other causes of CIC. If patients do not respond to these simple changes, then treatment with osmotic and stimulant laxatives should be trialled. Patients not responding to traditional laxatives should be offered treatment with prosecretory agents such as lubiprostone, linaclotide and plecanatide, or the 5-HT4 receptor agonist prucalopride, where available. If there is no response to pharmacological treatment, surgical intervention can be considered, but it is only suitable for a carefully selected subset of patients with proven slow transit constipation.

The overlap syndrome of urticaria and gastroesophageal reflux disease

BACKGROUND

One-quarter of systemic symptoms associated with chronic spontaneous urticaria (CSU) are related to gastrointestinal complaints (GICs).

OBJECTIVES

To investigate the prevalence and features of urticaria-overlapping GICs.

METHODS

In this retrospective cross-sectional survey, 1426 consecutive outpatients were observed at our University Department. Only patients suffering from urticaria or GICs with a complete diagnostic work-up including serum total IgE level (Tot-IgE), differential blood count and urticaria activity score (UAS), were evaluated.

RESULTS

Among different GICs, gastroesophageal reflux disease (GERD) was the most frequent syndrome observed (15.4%; 95%CI: 13.6-17.3). The prevalence of overlap syndrome for urticaria and GERD was 5.9% (95%CI: 4.7-7.2). In urticaria-patients, the prevalence of GERD was four-fold higher than in patients without hives (44% vs. 11%, p<0.001). UAS was significantly higher in urticaria and GERD overlap syndromes vs. isolated urticarias. In patients with GERD or acute/chronic urticaria or overlap syndrome, Tot-IgE and eosinophil blood count (EBC) differed significantly, with a stepwise increase in their values; from the subgroup of patients with GERD only, to that with overlap of CSU to GERD. Prevalence values for urticaria overlapping with GERD were three- and two-fold higher in CSU and in long-duration GERD cases respectively compared to acute urticaria or short-duration GERD cases. Similar to Th2 pathology models, CSU and GERD overlap syndrome was significantly and independently associated with Total-IgE ≥100IU/ml or EBC ≥250/mmc compared to CSU or GERD. Endoscopic/bioptic findings of non-erosive reflux disease (NERD) or Barrett's esophagus (BE) were more frequent in chronic overlap syndrome than in GERD-patients.

CONCLUSIONS

GERD was the most frequent GIC in patients with urticaria. Overlap syndrome was more frequent among patients with CSU, where this syndrome was associated with higher values of UAS, Tot-IgE, EBC and frequencies of NERD and BE. These results suggest that overlap syndrome is frequently a chronic syndrome with a Th2-like profile.

Insights into the evaluation and management of dyspepsia: recent developments and new guidelines

Dyspepsia is a very common gastrointestinal (GI) condition worldwide. We critically examine the recommendations of recently published guidelines for the management of dyspepsia, including those produced jointly by the American College of Gastroenterology and the Canadian Association of Gastroenterology, and those published by the UK National Institute for Health and Care Excellence. Dyspepsia is a symptom complex, characterized by a range of upper GI symptoms including epigastric pain or burning, early satiety, and post-prandial fullness. Although alarm features are used to help prioritize access to upper GI endoscopy, they are of limited utility in predicting endoscopic findings, and the majority of patients with dyspepsia will have no organic pathology identified at upper GI endoscopy. These patients are labelled as having functional dyspepsia (FD). The Rome IV criteria, which are used to define FD, further subclassify patients with FD as having either epigastric pain syndrome or post-prandial distress syndrome, depending on their predominant symptoms. Unfortunately, the Rome criteria perform poorly at identifying FD without the need for upper GI endoscopy. This has led to the investigation of alternative diagnostic approaches, including whether a capsaicin pill or combined serum biomarkers can accurately identify patients with FD. However, there is insufficient evidence to support either of these approaches at the present time. Patients with FD should be tested for H. pylori infection and be prescribed eradication therapy if they test positive. If they continue to have symptoms following this, then a trial of treatment with a proton pump inhibitor (PPI) should be given for up to 8 weeks. In cases where symptoms fail to adequately respond to PPI treatment, a tricyclic antidepressant may be of benefit, and should be continued for 6 to 12 months in patients who respond. Prokinetics demonstrate limited efficacy for treating FD, but could be considered if other strategies have failed. However, there are practical difficulties due to their limited availability in some countries and the risk of serious side effects. Patients with FD who fail to respond to drug treatments should be offered psychological therapy, where available. Overall, with the exception of recommendations relating to H. pylori testing and the prescription of PPIs, which are made on the basis of high-quality evidence, the evidence underpinning other elements of dyspepsia management is largely of low-quality. Consequently, there are still many aspects of the evaluation and management of dyspepsia that require further research.

New treatments and therapeutic targets for IBS and other functional bowel disorders

Functional bowel disorders (FBDs) are a spectrum of disorders characterized by combinations of symptoms attributable to the lower gastrointestinal tract. Most current first-line therapies for IBS and other FBDs target the predominant symptom and mainly affect one symptom in the symptom complex. Additional broadly effective treatment alternatives targeting the entire symptom complex are needed. New drugs for FBDs (such as lubiprostone, linaclotide, plecanatide, prucalopride, eluxadoline and rifaximin) target key mechanisms in the pathophysiology of these disorders and improve both the abnormal bowel habit and other key symptoms, such as abdominal pain and bloating. The current development of new treatment alternatives is focusing on different aspects of the complex pathophysiology of IBS and other FBDs: gut microenvironment (via diet and modulation of gut microbiota), enterohepatic circulation of bile acids, gastrointestinal secretion, motility and sensation, gut-brain interactions, gut barrier function and the immune system within the gastrointestinal tract. Studies also suggest that personalized treatment of IBS and other FBDs is possible using various diagnostic markers.

How the Change in IBS Criteria From Rome III to Rome IV Impacts on Clinical Characteristics and Key Pathophysiological Factors

OBJECTIVES

The diagnostic criteria for irritable bowel syndrome (IBS) have recently been updated from Rome III to Rome IV. Whereas in Rome III a diagnosis of IBS entailed chronic abdominal pain or discomfort at least 3 days per month, in Rome IV the term discomfort has been removed and the frequency of abdominal pain increased to at least 1 day per week. We examined how this change in IBS criteria impacts on clinical characteristics and pathophysiological factors.

METHODS

A total of 542 Swedish subjects with Rome III IBS completed a baseline questionnaire enquiring for the number of abdominal pain days in the last 10 days; this was subsequently used as a surrogate marker to identify Rome IV IBS, in that (a) those with 0 or 1 day of pain were classed as Rome IV-negative, and (b) those with ≥2 days of pain were classed as Rome IV-positive. Comparisons were made between Rome IV-positive and -negative IBS groups for demographics, IBS subtype, gastrointestinal and psychological symptoms, somatisation, fatigue, disease-specific quality of life, rectal sensitivity, and oro-anal transit time.

RESULTS

Overall, 85% of Rome III IBS patients fulfilled the Rome IV criteria for IBS, but 15% did not. Rome IV-positive subjects were significantly more likely to be female, have poorer quality of life, greater pain severity, bloating, somatisation, fatigue, and rectal sensitivity than Rome IV-negative subjects. There were no differences in severity of anxiety or depression, IBS subtypes, bowel habit dissatisfaction, or oro-anal transit time. Finally, increasing number of pain days correlated positively with symptoms and visceral hypersensitivity.

CONCLUSIONS

Most Rome III-positive IBS patients seeking healthcare fulfil the Rome IV IBS criteria. They constitute a more severe group than those who lose their IBS diagnosis.

Lower and Upper Gastrointestinal Symptoms Differ Between Individuals With Irritable Bowel Syndrome With Constipation or Chronic Idiopathic Constipation

BACKGROUND/AIMS

We evaluated the distribution of lower and upper gastrointestinal (GI) symptoms among individuals with irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC) in a nationwide survey.

METHODS

Individuals (≥ 18 years of age) were identified from a nationwide sample of ＞ 70 000 United States adults. Participants completed the National Institutes of Health GI Patient Reported Outcomes Measurement Information System (NIH GI-PROMIS) questionnaire. Symptom frequency and intensity in the prior 7 days were assessed using validated PROMIS scores. Odds ratios (OR) with 95% confidence intervals (CI) were calculated to compare symptom prevalence in IBS-C vs CIC, and one-way ANOVA was used to assess differences in PROMIS scores. Regression analysis was performed to adjust for demographic variables.

RESULTS

Nine hundred and seventy adults met eligibility criteria (275 with IBS-C, 734 with CIC). Demographics were similar among groups except for education, marital and employment status, and income. Adjusting for demographic differences, GI-PROMIS scores of global GI symptoms were higher in IBS-C (251.1; 95% CI, 230.0-273.1) compared to CIC (177.8; 95% CI 167.2-188.4) (P ＜ 0.001). Abdominal pain was more prevalent (OR, 4.3; 95% CI, 2.9-6.6) and more severe (P = 0.007) in IBS-C. Constipation was more severe in IBS-C (P = 0.011). Incontinence was more common (OR, 2.9; 95% CI, 1.3-6.3) but just as severe (P = 0.389) in IBS-C versus CIC. Regarding upper GI symptoms, the prevalence of dysphagia, heartburn, and nausea were similar. However, IBS-C individuals had more severe heartburn (P = 0.001).

CONCLUSION

GI symptoms are generally more severe in IBS-C compared to CIC, however abdominal pain, bloating, and upper GI symptoms still commonly occur in CIC.

Self-reported Sleep Impairment in Functional Dyspepsia and Irritable Bowel Syndrome

BACKGROUND/AIMS

Sleep impairment is a common complaint among patients with irritable bowel syndrome (IBS) and functional dyspepsia (FD). This study aimed to evaluate the prevalence of sleep impairment in FD or IBS patients, and to determine whether IBS-FD overlap induced more sleep disturbance than FD or IBS alone.

METHODS

A population-based cohort in South Korea including 2251 subjects was asked about gastrointestinal symptoms including IBS and dyspepsia-related symptoms. In addition, sleep disturbance was measured using the Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale questionnaires. One-way ANOVA and logistic regression were used to assess differences among the 4 groups (healthy subjects, IBS alone, FD alone, and IBS-FD overlap).

RESULTS

Of 2251 subjects who were surveyed by questionnaire, 2031 responded (92.5% response rate) and were analyzed. The prevalence of IBS, FD, and IBS-FD overlap was 8.0% (95% confidence interval [CI], 6.8-9.2%), 4.8% (95% CI, 3.9-5.8%), and 1.8% (95% CI, 1.2-2.4%), respectively. FD alone, but not IBS alone, was significantly associated with a poorer sleep quality index (OR, 2.68; 95% CI, 1.43-5.01) and more daytime sleepiness (OR, 2.21; 95% CI, 1.14-4.30), compared to healthy subjects. IBS-FD overlap had the greatest likelihood of a poorer sleep quality index (OR, 3.88; 95% CI, 1.83-8.19), daytime sleepiness (OR, 2.47; 95% CI, 1.01-5.67), and insomnia (OR, 2.84; 95% CI, 1.39-5.82), compared to healthy subjects.

CONCLUSION

A correlation between functional gastrointestinal disorders and sleep disturbance was demonstrated, which was significantly pronounced in the context of IBS-FD overlap.

Self-reported Sleep Impairment in Functional Dyspepsia and Irritable Bowel Syndrome

Background/Aims

Sleep impairment is a common complaint among patients with irritable bowel syndrome (IBS) and functional dyspepsia (FD). This study aimed to evaluate the prevalence of sleep impairment in FD or IBS patients, and to determine whether IBS-FD overlap induced more sleep disturbance than FD or IBS alone.

Methods

A population-based cohort in South Korea including 2251 subjects was asked about gastrointestinal symptoms including IBS and dyspepsia-related symptoms. In addition, sleep disturbance was measured using the Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale questionnaires. One-way ANOVA and logistic regression were used to assess differences among the 4 groups (healthy subjects, IBS alone, FD alone, and IBS-FD overlap).

Results

Of 2251 subjects who were surveyed by questionnaire, 2031 responded (92.5% response rate) and were analyzed. The prevalence of IBS, FD, and IBS-FD overlap was 8.0% (95% confidence interval [CI], 6.8–9.2%), 4.8% (95% CI, 3.9–5.8%), and 1.8% (95% CI, 1.2–2.4%), respectively. FD alone, but not IBS alone, was significantly associated with a poorer sleep quality index (OR, 2.68; 95% CI, 1.43–5.01) and more daytime sleepiness (OR, 2.21; 95% CI, 1.14–4.30), compared to healthy subjects. IBS-FD overlap had the greatest likelihood of a poorer sleep quality index (OR, 3.88; 95% CI, 1.83–8.19), daytime sleepiness (OR, 2.47; 95% CI, 1.01–5.67), and insomnia (OR, 2.84; 95% CI, 1.39–5.82), compared to healthy subjects.

Conclusion

A correlation between functional gastrointestinal disorders and sleep disturbance was demonstrated, which was significantly pronounced in the context of IBS-FD overlap.

Advancements in drug development for diarrhea-predominant irritable bowel syndrome

INTRODUCTION

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common disorder characterized by a complex pathophysiology hampering optimal targeted drug development. Recent advances in our understanding of key underlying mechanisms prompted novel therapeutics including novel pharmacological approaches.

AREAS COVERED

This review summarizes the latest advancements in the pipeline of IBS-D drugs focusing on new pharmacological targets, efficacy and safety of medicinal products considering the recent harmonization of regulatory requirements by the FDA and the EMA.

EXPERT OPINION

The new 5-HT3 receptor antagonist ramosetron appears a promising therapeutic approach devoid of significant adverse events, although it is presently unavailable in Western countries, most likely because of the precautionary approach taken by regulatory agencies with this drug class. New pharmacological concepts on full agonists/antagonists, mixed-receptor activity and novel drug targets may streamline the present drug pipeline along with the adherence on new regulatory guidelines on outcome measures. Eluxadoline can be taken as an example of this paradigm shift. It has now been granted marketing authorization for IBS-D on both sides of the Atlantic, but it is still considered as a second-line agent by the NICE. There is still much work to be done to fully cover clinical needs of patients with IBS-D.

The Prevalence and Impact of Overlapping Rome IV-Diagnosed Functional Gastrointestinal Disorders on Somatization, Quality of Life, and Healthcare Utilization: A Cross-Sectional General Population Study in Three Countries

OBJECTIVES

The population prevalence of Rome IV-diagnosed functional gastrointestinal disorders (FGIDs) and their cumulative effect on health impairment is unknown.

METHODS

An internet-based cross-sectional health survey was completed by 5,931 of 6,300 general population adults from three English-speaking countries (2100 each from USA, Canada, and UK). Quota-based sampling was used to generate demographically balanced and population representative samples with regards to age, sex, and education level. The survey enquired for demographics, medication, surgical history, somatization, quality of life (QOL), doctor-diagnosed organic GI disease, and criteria for the Rome IV FGIDs. Comparisons were made between those with Rome IV-diagnosed FGIDs against non-GI (healthy) and organic GI disease controls.

RESULTS

The number of subjects having symptoms compatible with a FGID was 2,083 (35%) compared with 3,421 (57.7%) non-GI and 427 (7.2%) organic GI disease controls. The most frequently met diagnostic criteria for FGIDs was bowel disorders (n=1,665, 28.1%), followed by gastroduodenal (n=627, 10.6%), anorectal (n=440, 7.4%), esophageal (n=414, 7%), and gallbladder disorders (n=10, 0.2%). On average, the 2,083 individuals who met FGID criteria qualified for 1.5 FGID diagnoses, and 742 of them (36%) qualified for FGID diagnoses in more than one anatomic region. The presence of FGIDs in multiple regions was associated with increasing somatization, worse mental/physical QOL, more medical therapies, and a higher prevalence of abdominal surgeries; all P<0.001. Notably, individuals with FGIDs in multiple regions had greater somatization and worse QOL than organic GI disease controls.

CONCLUSIONS

Roughly a third of the general adult population fulfils diagnostic criteria for a Rome IV FGID. In a third of this subset multiple GI regions are involved and this overlap is associated with increased health impairment.

Frequency patterns of core constipation symptoms among the Asian adults: a systematic review

BACKGROUND

In clinical practice, assessment of constipation depends on reliability, consistency and frequency of several commonly reported or core symptoms. It is not known if frequency patterns of constipation symptoms in adults are different between the West and the East. This review aimed to describe core constipation symptoms and their frequency patterns among the Asian adults.

METHODS

Articles published in PubMed, MEDLINE, CINAHL and Science Direct from 2005 to 2015 were searched systematically. Studies were included if constipation satisfied the Rome II and or III criteria. Study populations consisted of Asian adults above 18 years old and with sample size above 50.

RESULTS

Of 2812 articles screened, 11 met the eligibility criteria. Constipation among Asian adults was characterized by three core symptoms of 'straining' at 82.8%, 'lumpy and hard stool' at 74.2% and 'sensation of incomplete evacuation' at 68.1% and the least frequent symptom was 'manual maneuver to facilitate defecation' at 23.3%. There was heterogeneity in frequency patterns of core symptoms between different Asian studies but also differences in core symptoms between constipation subtypes of functional constipation and irritable bowel syndrome with constipation.

CONCLUSIONS

In general, Asian adults perceive constipation symptoms in a similar but not equivalent manner to the West. Recognition of core symptoms will increase the diagnostic confidence of constipation and its subtypes but more studies of the various specific Asian populations are needed to address their differences.

A positive SeHCAT test results in fewer subsequent investigations in patients with chronic diarrhoea

Chronic diarrhoea is a common condition, resulting from a number of different disorders. Bile acid diarrhoea, occurring in about a third of these patients, is often undiagnosed. We hypothesised that a positive diagnosis of bile acid diarrhoea would reduce the need for subsequent investigations for alternative diagnoses.

METHODS

Patients previously recruited to a study of chronic diarrhoea who had selenium homocholic acid taurine (SeHCAT) testing and subsequent follow-up at our institution were identified. In a retrospective analysis, the numbers of defined investigations undertaken from the first 3 months after SeHCAT in the following 5 years were compared.

RESULTS

90 patients were identified with primary bile acid diarrhoea (SeHCAT retention <15%, n=36) or idiopathic diarrhoea (SeHCAT retention >15%, n=54). Follow-up had been performed on 29 and 39 subjects, respectively, with no differences in previous investigations or the last contact date. In the follow-up period, the proportions of these patients who had undergone endoscopic procedures (gastroscopy, colonoscopy and sigmoidoscopy) were the same. However, there was a higher proportion of patients in the SeHCAT-negative group who had other investigations, including imaging, physiological tests and blood tests (p=0.037). The use of cross-sectional imaging was significantly higher in this group (p=0.015) with greater proportions having CT (0.44 vs 0.10) and MRI (0.26 vs 0.07). Ultrasound use and the number of blood tests were higher in the SeHCAT-negative group whereas the SeHCAT-positive group attended more clinic appointments (p=0.013).

CONCLUSION

A positive diagnosis of bile acid diarrhoea, made by a SeHCAT test, resulted in reduced use of diagnostic investigations over the subsequent 5 years.

Smoking in Irritable Bowel Syndrome: A Systematic Review

OBJECTIVE

The aim of this review was to examine (1) the prevalence of smoking in subjects with irritable bowel syndrome (IBS), (2) whether smoking prevalence significantly differs between subjects with and without IBS, and (3) whether smoking significantly predicts the presence or the development of IBS.

METHODS

Articles were retrieved by systematically searching the Scopus, Web of Science, and PubMed electronic databases from inception to July 2016, using the keywords "smoking" and "tobacco" combined with "irritable bowel syndrome." Reference lists of included articles were also searched. Articles were included if they (1) reported data on smoking prevalence in subjects with IBS and/or on the association (assessed by means of multivariate analyses) between smoking and IBS, (2) identified IBS according to Manning criteria or Rome I-III criteria, (3) were English-language articles, and (4) involved only adult subjects.

RESULTS

The electronic searches yielded a total of 1,637 records, and 42 articles met inclusion criteria. Another 13 articles were retrieved through manual search, leading to a total of 55 included articles. Smoking prevalence in subjects with IBS was assessed by 48 articles and ranged from 0% in university students to 47.1% in patients with microscopic colitis. Thirty-three articles compared smoking prevalence between subjects with and without IBS. In 25 articles no significant difference was found. In seven articles smoking was significantly more frequent in subjects with IBS compared to those without IBS, while one study found a significantly higher smoking prevalence in controls. Eighteen multivariate analyses assessing the association between smoking and IBS were presented in 16 articles. Only one study employed a prospective design. In 11 analyses, smoking was not significantly associated with IBS after adjusting for covariates. In seven studies smoking independently predicted the presence of IBS.

CONCLUSIONS

According to the selected articles, a significant association between smoking and IBS cannot be confirmed. However, different shortcomings may hinder generalizability and comparability of many studies. A dimensional assessment of smoking, a prospective design, the differentiation between IBS subgroups, and the recruitment of patients in clinical settings, especially in primary care, are necessary to clarify the role of smoking in IBS.

Multiple functional gastrointestinal disorders linked to gastroesophageal reflux and somatization: A population-based study

BACKGROUND

It is unknown why functional gastrointestinal disorders (FGIDs) overlap and limited information exists on risk factors for those with overlap. Our aim was to estimate the prevalence of combinations of FGIDs including reflux (FGIDs-gastroesophageal reflux [GER]), and evaluate potential risk factors for people with multiple disorders in a representative US community.

METHODS

A population-based study was conducted by mailing a valid GI symptom questionnaire to an age- and gender-stratified random sample of residents of Olmsted County, MN. Rome III definitions were used to identify people with FGIDs, and GER was defined by weekly or more frequent heartburn or acid regurgitation. The prevalence of people meeting multiple symptom complexes was estimated. Moreover, potential risk factors for people with multiple disorders were evaluated.

KEY RESULTS

A total of 3548 people provided data for each of the necessary symptom questions (mean age: 61±16 years, 54% female). Among these 3548 subjects, 2009 (57%) had no FGIDs-GER, 906 (26%) had a pure FGID-GER, 372 (10%) had 2 FGIDs-GER, and 261 (7%) had 3 or more FGIDs-GER. Somatization as assessed by a higher Somatic Symptom Checklist score (OR=3.3, 95% CI [2.7,4.1]) was associated with an increased odds for those with 3 or more FGIDs-GER compared to subjects with a pure FGID-GER adjusting for age and gender.

CONCLUSIONS AND INFERENCES

Symptom complex overlap is common rather than rare in the community. GER is an integral symptom complex associated with both upper and lower FGIDs. Somatization is a strong risk factor for multiple FGIDs.

Establishing a nurse-led pelvic floor and functional bowel service

Jane Turner, Colorectal Nurse Specialist, Cardiff and Vale University Health Board, was awarded a travel scholarship by the Florence Nightingale Foundation. She used it to find out about the running of nurse-led pelvic floor and functional bowel services around the UK.

Obesity Is Inversely Related to Hydrogen-Producing Small Intestinal Bacterial Overgrowth in Non-Constipation Irritable Bowel Syndrome

There have been inconsistent findings on the association of obesity and non-constipation irritable bowel syndrome (IBS). Small intestinal bacterial overgrowth (SIBO) with hydrogen (H₂) gas forming-microflora causes non-constipation IBS. But, the effect of H₂ producing SIBO on obesity in non-constipation IBS patients has not been studied yet. The aim of this study was to investigate the association between obesity and SIBO in non-constipation IBS patients. We reviewed the charts of patients who showed IBS symptoms along with the documented results of their lactulose hydrogen breath test (LHBT) for SIBO. Multivariate models were used to assess the association between obesity and SIBO. Four-hundred fifty-eight patients were retrospectively included in the study. Of the 485 IBS patients, 158 (30.7%) subjects had positive results for LHBT. Subjects without SIBO showed significantly higher levels of body mass index (24.8 vs. 23.3; P < 0.001) and waist circumference (86.5 vs. 82.7; P < 0.001) as compared to subjects with SIBO. In multivariate analysis, the odds ratios of SIBO were 0.396 (P = 0.018) for obesity and 0.482 (P = 0.021) for abdominal obesity. This is the first human study to demonstrate that obesity is inversely related to SIBO with H₂ gas production in non-constipation IBS patients.

Proteomics and irritable bowel syndrome

Irritable bowel syndrome (IBS) is a gastrointestinal disease that according to Rome IV criteria is subdivided into four subtypes. The pathophysiology of this disease is not well understood due to numerous factors playing multiple roles in disease development, such as diet, stress and hormones. IBS has a variety of symptoms and overlaps with many other gastrointestinal and non-gastrointestinal diseases. Area covered: This review aims to present an overview of implementation of proteomics in experimental studies in the field of IBS. Expert commentary: Proteomics is commonly used for biomarker discovery in and has also been extensively used in IBS research. The necessity of a sensitive and specific biomarker for IBS is apparent, but despite the intensive research performed in this field, an appropriate biomarker is not yet available.