Efficacy of soluble fibre, antispasmodic drugs, and gut–brain neuromodulators in irritable bowel syndrome: a systematic review and network meta-analysis

Chronic Visceral Pain: New Peripheral Mechanistic Insights and Resulting Treatments

Chronic visceral pain is one of the most common reasons for patients with gastrointestinal disorders, such as inflammatory bowel disease or disorders of brain-gut interaction, to seek medical attention. It represents a substantial burden to patients and is associated with anxiety, depression, reductions in quality of life, and impaired social functioning, as well as increased direct and indirect health care costs to society. Unfortunately, the diagnosis and treatment of chronic visceral pain is difficult, in part because our understanding of the underlying pathophysiologic basis is incomplete. In this review, we highlight recent advances in peripheral pain signaling and specific physiologic and pathophysiologic preclinical mechanisms that result in the sensitization of peripheral pain pathways. We focus on preclinical mechanisms that have been translated into treatment approaches and summarize the current evidence base for directing treatment toward these mechanisms of chronic visceral pain derived from clinical trials. The effective management of chronic visceral pain remains of critical importance for the quality of life of suffers. A deeper understanding of peripheral pain mechanisms is necessary and may provide the basis for novel therapeutic interventions.

Treating disorders of brain-gut interaction with multidisciplinary integrated care. Moving towards a new standard of care

Disorders of brain-gut interaction (DGBI) are highly prevalent in our community with a negative burden on the quality of life and function. Symptoms are frequently food-induced, and psychological disorders are commonly co-morbid and contribute greatly to symptom severity and healthcare utilization, which can complicate management. Pathophysiological contributors to the development and maintenance of DGBI are best appreciated within the biopsychosocial model of illness. Established treatments include medical therapies targeting gastrointestinal physiology, luminal microbiota or visceral sensitivity, dietary treatments including dietary optimization and specific therapeutic diets such as a low-FODMAP diet, and psychological interventions. The traditional "medical model" of care, driven predominantly by doctors, poorly serves sufferers of DBGI, with research indicating that a multidisciplinary, integrated-care approach produces better outcomes. This narrative review explores the current evidence for multidisciplinary care and provides the best practice recommendations for physicians and healthcare systems managing such patients.

Asociación Española de Neurogastroenterología y Motilidad (ASENEM) updated review on the management of functional abdominal pain

Functional abdominal pain is a disorder in which central and peripheral sensitization processes converge, leading to hypersensitivity and allodynia. Differential diagnosis is made with organic digestive, renal, gynecological, endocrine, or neurological diseases. Treatment should be individualized for each patient. In cases of debilitating pain, therapy combining drugs with different mechanisms of action can be initiated, while in less severe cases, therapy with a progressive introduction of drugs based on clinical response is advised. The first line includes general lifestyle advice and antispasmodic substances, like peppermint oil, anticholinergic/antimuscarinic, and calcium channels antagonists. In the second line of treatment, neuromodulating agents are added. Finally, when these measures fail, third-line treatments such as gabapentine and atypical antipsychotics are considered. Psychological interventions should be considered if specialized therapists are available to manage these disorders.

Unmet needs of drugs for irritable bowel syndrome and inflammatory bowel diseases: interest of vagus nerve stimulation and hypnosis

The gut and the brain communicate bidirectionally through the autonomic nervous system. The vagus nerve is a key component of this gut-brain axis, and has numerous properties such as anti-inflammatory, antinociceptive, anti-depressive effects. A perturbation of this gut-brain communication is involved in the pathogeny of functional digestive disorders, such as irritable bowel syndrome, and inflammatory bowel diseases. Stress plays a role in the pathogeny of these diseases, which are biopsychosocial models. There are presently unmet needs of pharmacological treatments of these chronic debilitating diseases. Treatments are not devoid of side effects, cost-effective, do not cure the diseases, can lose effects over time, thus explaining the poor satisfaction of patients, their lack of compliance, and their interest for non-drug therapies. The gut-brain axis can be targeted for therapeutic purposes in irritable bowel syndrome and inflammatory bowel disease through non-drug therapies, such as hypnosis and vagus nerve stimulation, opening up possibilities for responding to patient expectations.

Journal of Clinical Gastroenterology Lectureship Dubai 2022 : Management of Irritable Bowel Syndrome With Diarrhea

Irritable bowel syndrome (IBS) with diarrhea (IBS-D) affects ~1% of the general population and is characterized by abdominal pain associated with diarrhea. IBS-D symptoms significantly impact the quality of life of patients. Major uncertainties remain regarding the optimal management of these patients. Several therapies have been investigated over the years for the treatment of IBS-D. In the initial management, commonly prescribed approaches with an effect on global IBS symptoms include a low Fermentable Oligo-, Di-, Mono-Saccharides and Polyols diet and probiotics, while antispasmodics are used for targeting abdominal pain and loperamide for diarrhea only. Additional therapeutic options for the relief of global IBS symptoms include rifaximin, 5-HT 3 antagonists, gut-directed psychological therapies, and eluxadoline, while tricyclic antidepressants can target abdominal pain and bile acid sequestrants diarrhea. Promising evidence exists for the use of mesalazine and fecal microbiota transplantation in IBS-D, although further evidence is needed for definitive conclusions regarding their efficacy.

Treatment of non-constipated irritable bowel syndrome with the histamine 1 receptor antagonist ebastine: a randomised, double-blind, placebo-controlled trial

OBJECTIVE

We evaluated the histamine 1 receptor antagonist ebastine as a potential treatment for patients with non-constipated irritable bowel syndrome (IBS) in a randomised, placebo-controlled phase 2 study.

METHODS

Non-constipated patients with IBS fulfilling the Rome III criteria were randomly assigned to 20 mg ebastine or placebo for 12 weeks. Subjects scored global relief of symptoms (GRS) and abdominal pain intensity (API). A subject was considered a weekly responder for GRS if total or obvious relief was reported and a responder for API if the weekly average pain score was reduced by at least 30% vs baseline. The primary endpoints were the proportion of subjects who were weekly responders for at least 6 out of the 12 treatment weeks for both GRS and API ('GRS+API', composite endpoint) and for GRS and API separately.

RESULTS

202 participants (32±11 years, 68% female) were randomly allocated to receive ebastine (n=101) or placebo (n=101). Treatment with ebastine resulted in significantly more responders (12%, 12/92) for GRS+API compared with placebo (4%, 4/87, p=0.047) while the proportion of responders for GRS and API separately was higher for ebastine compared with placebo, although not statistically significant (placebo vs ebastine, GRS: 7% (6/87) vs 15% (14/91), p=0.072; API: 25% (20/85) vs 37% (34/92), p=0.081).

CONCLUSIONS

Our study shows that ebastine is superior to placebo and should be further evaluated as novel treatment for patients with non-constipated IBS.

TRIAL REGISTRATION NUMBER

The study protocol was approved by the local ethics committee of each study site (EudraCT number: 2013-001199-39; ClinicalTrials.gov identifier: NCT01908465).

The Role of the FODMAP Diet in IBS

The low FODMAP (fermentable oligosaccharide, disaccharide, monosaccharide, and polyol) diet is a beneficial therapeutic approach for patients with irritable bowel syndrome (IBS). However, how the low FODMAP diet works is still not completely understood. These mechanisms encompass not only traditionally known factors such as luminal distension induced by gas and water but also recent evidence on the role of FOMAPs in the modulation of visceral hypersensitivity, increases in intestinal permeability, the induction of microbiota changes, and the production of short-chain fatty acids (SCFAs), as well as metabolomics and alterations in motility. Although most of the supporting evidence is of low quality, recent trials have confirmed its effectiveness, even though the majority of the evidence pertains only to the restriction phase and its effectiveness in relieving abdominal bloating and pain. This review examines potential pathophysiological mechanisms and provides an overview of the existing evidence on the effectiveness of the low FODMAP diet across various IBS subtypes. Key considerations for its use include the challenges and disadvantages associated with its practical implementation, including the need for professional guidance, variations in individual responses, concerns related to microbiota, nutritional deficiencies, the development of constipation, the necessity of excluding an eating disorder before commencing the diet, and the scarcity of long-term data. Despite its recognized efficacy in symptom management, acknowledging these limitations becomes imperative for a nuanced comprehension of the role of a low FODMAP diet in managing IBS. By investigating its potential mechanisms and evidence across IBS subtypes and addressing emerging modulations alongside limitations, this review aims to serve as a valuable resource for healthcare practitioners, researchers, and patients navigating the intricate landscape of IBS.

Evaluation of the efficacy of probiotics as treatment in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a gastrointestinal functional disorder mainly characterised by abdominal pain, bloating and altered bowel habits. Dysbiosis might seem to be involved in the pathogenesis of the disease. Probiotics represent a potential treatment, since these could favour the functional microbiota and improve symptoms. The aim was to review the effectiveness of the use of probiotics in IBS symptomatology, analysing the influence of duration and dose. 18 articles were included. At the individual level, Lactobacillus, Bifidobacterium and Bacillus could be useful in the treatment of symptoms. Bifidobacterium bifidum reported the best results (1 × 109 CFU/day for 4 weeks). The most effective combination was 2 Lactobacillus strains, one of Bifidobacterium and one of Streptococcus (4 × 109 CFU/day for 4 weeks). Future clinical trials should confirm these results and analyse the difference between individual and combined treatments.

A Diagnosis of Irritable Bowel Syndrome Using Rome IV Criteria and Limited Investigations is Durable in Secondary Care

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) is a positive diagnosis, made using symptom-based criteria and limited, judicious, investigation. However, this may lead to uncertainty on the part of clinicians regarding potential for a missed diagnosis of organic gastrointestinal disease. Few studies have examined durability of a diagnosis of IBS, and none have used the current gold standard to diagnose IBS, the Rome IV criteria.

METHODS

We collected complete symptom data from 373 well-characterized adults meeting Rome IV criteria for IBS referred to a single UK clinic between September 2016 and March 2020. All patients underwent relatively standardized work-up to exclude relevant organic disease before diagnosis. We followed these individuals up to December 2022, assessing rates of rereferral, reinvestigation, and missed organic gastrointestinal disease.

RESULTS

During a mean follow-up of 4.2 years per patient (total follow-up in all patients, 1565 years), 62 (16.6%) patients were rereferred. Of these, 35 (56.5%) were rereferred for IBS and 27 (43.5%) for other gastrointestinal symptoms. Among the 35 rereferred with IBS this was caused by a change in symptoms in only 5 (14.3%). Reinvestigation was undertaken in 21 (60.0%) of 35 rereferred with IBS and 22 (81.5%) of 27 rereferred with other symptoms (P = .12). Only 4 (9.3% of those reinvestigated and 1.1% of the entire cohort) new cases of relevant organic disease, which may have been responsible for IBS symptoms at baseline, were identified (1 case of chronic calcific pancreatitis among those rereferred with IBS and 1 case each of inflammatory bowel disease-unclassified, moderate bile acid diarrhea, and small bowel obstruction among those rereferred with other gastrointestinal symptoms).

CONCLUSIONS

Despite rereferral for gastrointestinal symptoms among 1 in 6 patients overall, with almost 10% rereferred with ongoing IBS symptoms, and substantial reinvestigation rates, missed organic gastrointestinal disease occurred in only 1%. A diagnosis of Rome IV IBS after limited investigation is safe and durable.

Amitriptyline at Low-Dose and Titrated for Irritable Bowel Syndrome as Second-Line Treatment in primary care (ATLANTIS): a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Most patients with irritable bowel syndrome (IBS) are managed in primary care. When first-line therapies for IBS are ineffective, the UK National Institute for Health and Care Excellence guideline suggests considering low- dose tricyclic antidepressants as second-line treatment, but their effectiveness in primary care is unknown, and they are infrequently prescribed in this setting.

METHODS

This randomised, double-blind, placebo-controlled trial (Amitriptyline at Low-Dose and Titrated for Irritable Bowel Syndrome as Second-Line Treatment [ATLANTIS]) was conducted at 55 general practices in England. Eligible participants were aged 18 years or older, with Rome IV IBS of any subtype, and ongoing symptoms (IBS Severity Scoring System [IBS-SSS] score ≥75 points) despite dietary changes and first-line therapies, a normal full blood count and C-reactive protein, negative coeliac serology, and no evidence of suicidal ideation. Participants were randomly assigned (1:1) to low-dose oral amitriptyline (10 mg once daily) or placebo for 6 months, with dose titration over 3 weeks (up to 30 mg once daily), according to symptoms and tolerability. Participants, their general practitioners, investigators, and the analysis team were all masked to allocation throughout the trial. The primary outcome was the IBS-SSS score at 6 months. Effectiveness analyses were according to intention-to-treat; safety analyses were on all participants who took at least one dose of the trial medication. This trial is registered with the ISRCTN Registry (ISRCTN48075063) and is closed to new participants.

FINDINGS

Between Oct 18, 2019, and April 11, 2022, 463 participants (mean age 48·5 years [SD 16·1], 315 [68%] female to 148 [32%] male) were randomly allocated to receive low-dose amitriptyline (232) or placebo (231). Intention-to-treat analysis of the primary outcome showed a significant difference in favour of low-dose amitriptyline in IBS-SSS score between groups at 6 months (-27·0, 95% CI -46·9 to -7·10; p=0·0079). 46 (20%) participants discontinued low-dose amitriptyline (30 [13%] due to adverse events), and 59 (26%) discontinued placebo (20 [9%] due to adverse events) before 6 months. There were five serious adverse reactions (two in the amitriptyline group and three in the placebo group), and five serious adverse events unrelated to trial medication.

INTERPRETATION

To our knowledge, this is the largest trial of a tricyclic antidepressant in IBS ever conducted. Titrated low-dose amitriptyline was superior to placebo as a second-line treatment for IBS in primary care across multiple outcomes, and was safe and well tolerated. General practitioners should offer low-dose amitriptyline to patients with IBS whose symptoms do not improve with first-line therapies, with appropriate support to guide patient-led dose titration, such as the self-titration document developed for this trial.

FUNDING

National Institute for Health and Care Research Health Technology Assessment Programme (grant reference 16/162/01).

"Sentinel or accomplice": gut microbiota and microglia crosstalk in disorders of gut-brain interaction

Abnormal brain-gut interaction is considered the core pathological mechanism behind the disorders of gut-brain interaction (DGBI), in which the intestinal microbiota plays an important role. Microglia are the "sentinels" of the central nervous system (CNS), which participate in tissue damage caused by traumatic brain injury, resist central infection and participate in neurogenesis, and are involved in the occurrence of various neurological diseases. With in-depth research on DGBI, we could find an interaction between the intestinal microbiota and microglia and that they are jointly involved in the occurrence of DGBI, especially in individuals with comorbidities of mental disorders, such as irritable bowel syndrome (IBS). This bidirectional regulation of microbiota and microglia provides a new direction for the treatment of DGBI. In this review, we focus on the role and underlying mechanism of the interaction between gut microbiota and microglia in DGBI, especially IBS, and the corresponding clinical application prospects and highlight its potential to treat DGBI in individuals with psychiatric comorbidities.

Chronic abdominal pain in inflammatory bowel disease: a practical guide

Pain is common in inflammatory bowel disease (IBD), yet many patients feel their pain is not addressed by healthcare professionals. Listening to a patient's concerns about pain, assessing symptoms and acknowledging the impact these have on daily life remain crucial steps in addressing pain in IBD. While acute pain may be effectively controlled by pain medication, chronic pain is more complex and often pharmacological therapies, particularly opioids, are ineffective. Low-dose tricyclic antidepressants and psychological approaches, including cognitive-behavioural therapy, have shown some promise in offering effective pain management while lifestyle changes such as a trial of low-fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet in those with overlapping irritable bowel syndrome may also reduce pain. Patients benefit from a long-term, trusting relationship with their healthcare professional to allow a holistic approach combining pharmacological, psychological, lifestyle and dietary approaches to chronic pain. We present a practical review to facilitate management of chronic abdominal pain in IBD.

Cognition of abdominal pain and abdominal discomfort in Chinese patients with irritable bowel syndrome with diarrhea

BACKGROUND

In Asia, the proportion of patients with irritable bowel syndrome (IBS) with abdominal discomfort alone is significantly higher than that in western countries. The purposes of this study are to understand the cognition of abdominal pain and abdominal discomfort in Chinese patients with IBS and to compare the clinical characteristics of patients with abdominal pain alone and with abdominal discomfort alone.

METHODS

Patients with IBS with diarrhea (IBS-D) who met the Rome III diagnostic criteria and had episodes of at least one day/week were consecutively enrolled. The cognition of abdominal pain and abdominal discomfort were investigated through face-to-face unstructured interview. Patients were divided into a pain group and a discomfort group according to the cognition interviews, then the characteristics and severity of symptoms (IBS symptom severity scale, IBS-SSS), IBS quality of life (IBS-QOL) and psychological state were compared between groups.

RESULTS

A total of 88 patients with IBS-D were enrolled. Most of the patients with self-reported abdominal pain described their pain as spasm/cramping; patients with self-reported abdominal discomfort had as many as 24 different descriptions of discomfort. Most patients having abdominal pain and discomfort could accurately distinguish the two symptoms. The degree of abdominal pain in the pain group was higher than abdominal discomfort in the discomfort group (P = 0.002). There was no significant difference in IBS-SSS, extra-intestinal pain, IBS-QOL, and psychological state between the two groups.

CONCLUSIONS

For Chinese patients with IBS-D, abdominal pain and abdominal discomfort are two different symptoms, but they have similar clinical features.

TRIAL REGISTRATION

ChiCTR, ChiCTR1900028082. Registered 11 December 2019 - Retrospectively registered, http://www.chictr.org.cn .

Irritable bowel syndrome and mental health comorbidity - approach to multidisciplinary management

Irritable bowel syndrome (IBS) affects 5-10% of the global population. Up to one-third of people with IBS also experience anxiety or depression. Gastrointestinal and psychological symptoms both drive health-care use in people with IBS, but psychological comorbidity seems to be more important for long-term quality of life. An integrated care approach that addresses gastrointestinal symptoms with nutrition and brain-gut behaviour therapies is considered the gold standard. However, best practice for the treatment of individuals with IBS who have a comorbid psychological condition is unclear. Given the rising prevalence of mental health disorders, discussion of the challenges of implementing therapy for people with IBS and anxiety and depression is critical. In this Review, we draw upon our expertise in gastroenterology, nutrition science and psychology to highlight common challenges that arise when managing patients with IBS and co-occurring anxiety and depression, and provide recommendations for tailoring clinical assessment and treatment. We provide best practice recommendations, including dietary and behavioural interventions that could be applied by non-specialists and clinicians working outside an integrated care model.

Managing pain in irritable bowel syndrome: current perspectives and best practice

INTRODUCTION

Irritable bowel syndrome (IBS) is characterized by chronic symptoms (>6 months) of abdominal pain in combination with a disturbed bowel habit. There is an association between the intensity of abdominal pain and the need for health care utilization. A bidirectionally disordered gut-brain interaction is central in the pathophysiology of IBS where a number of factors, gastrointestinal and non-gastrointestinal, can contribute to the illness experience. In order to treat abdominal pain in IBS, mapping these factors in a multidimensional clinical profile is helpful.

AREAS COVERED

This review covers basic epidemiology and pathophysiology of abdominal pain in IBS, the diagnostic approach, and a multidimensional treatment model where the management of abdominal pain is in focus.

EXPERT OPINION

A personalized treatment of abdominal pain in IBS is possible in patients who understand the diagnosis, the potential of therapies used, and where a good continuity in the patient-doctor relationship is established.

Antibiotics and Probiotics for Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a disorder of a gut-brain interaction characterised by abdominal pain and a change in stool form or frequency. Current symptom-based definitions and the classification of IBS promote heterogeneity amongst patients, meaning that there may be several different pathophysiological abnormalities leading to similar symptoms. Although our understanding of IBS is incomplete, there are several indicators that the microbiome may be involved in a subset of patients. Techniques including a faecal sample analysis, colonic biopsies, duodenal aspirates or surrogate markers, such as breath testing, have been used to examine the gut microbiota in individuals with IBS. Because of a lack of a clear definition of what constitutes a healthy gut microbiota, and the fact that alterations in gut microbiota have only been shown to be associated with IBS, a causal relationship is yet to be established. We discuss several hypotheses as to how dysbiosis may be responsible for IBS symptoms, as well as potential treatment strategies. We review the current evidence for the use of antibiotics and probiotics to alter the microbiome in an attempt to improve IBS symptoms. Rifaximin, a non-absorbable antibiotic, is the most studied antibiotic and has now been licensed for use in IBS with diarrhoea in the USA, but the drug remains unavailable in many countries for this indication. Current evidence also suggests that certain probiotics, including Lactobacillus plantarum DSM 9843 and Bifidobacterium bifidum MIMBb75, may be efficacious in some patients with IBS. Finally, we describe the future challenges facing us in our attempt to modulate the microbiome to treat IBS.

Survey-Based Analysis of the Clinical Treatment Status of Irritable Bowel Syndrome in Korea

BACKGROUND

The quality-of-life of patients with irritable bowel syndrome is low; incorrect diagnosis/treatment causes economic burden and inappropriate consumption of medical resources. This survey-based study aimed to analyze the current status of irritable bowel syndrome treatment to examine differences in doctors' perceptions of the disease, and treatment patterns.

METHODS

From October 2019 to February 2020, the irritable bowel syndrome and Intestinal Function Research Study Group of the Korean Society of Neurogastroenterology and Motility conducted a survey on doctors working in primary, secondary, and tertiary healthcare institutions. The questionnaire included 37 items and was completed anonymously using the NAVER platform (a web-based platform), e-mails, and written forms.

RESULTS

A total of 272 doctors responded; respondents reported using the Rome IV diagnostic criteria (amended in 2016) for diagnosing and treating irritable bowel syndrome. Several differences were noted between the primary, secondary, and tertiary physicians' groups. The rate of colonoscopy was high in tertiary healthcare institutions. During a colonoscopy, the necessity of random biopsy was higher among physicians who worked at tertiary institutions. 'The patient did not adhere to the diet' as a reason for ineffectiveness using low-fermentable oligo-, di-, and mono-saccharides, and polyols diet treatment was higher among physicians in primary/secondary institutions, and 'There are individual differences in terms of effectiveness' was higher among physicians in tertiary institutions. In irritable bowel syndrome constipation predominant subtype, the use of serotonin type 3 receptor antagonist (ramosetron) and probiotics was higher in primary/secondary institutions, while serotonin type 4 receptor agonist was used more in tertiary institutions. In irritable bowel syndrome diarrhea predominant subtype, the use of antispasmodics was higher in primary/secondary institutions, while the use of serotonin type 3 receptor antagonist (ramosetron) was higher in tertiary institutions.

CONCLUSION

Notable differences were observed between physicians in primary/secondary and tertiary institiutions regarding the rate of colonoscopy, necessity of random biopsy, the reason for the ineffectiveness of low-fermentable oligo-, di-, and mono-saccharides, and polyols diet, and use of drug therapy in irritable bowel syndrome. In South Korea, irritable bowel syndrome is diagnosed and treated according to the Rome IV diagnostic criteria, revised in 2016.

Pharmacological and nutritional therapy of children and adults with chronic intestinal pseudo-obstruction

INTRODUCTION

Chronic intestinal pseudo-obstruction (CIPO) is a rare, heterogeneous and severe form of gastrointestinal dysmotility.

AREAS COVERED

Pertinent literature on pediatric and adult CIPO management has been assessed via PubMed, Scopus, and EMBASE from inception to June 2022. Prokinetics, aimed at restoring intestinal propulsion (e.g. orthopramides and substituted benzamides, acetyl cholinesterase inhibitors, serotonergic agents and others), have been poorly tested and the available data showed only partial efficacy. Moreover, some prokinetic agents (e.g. orthopramides and substituted benzamides) can cause major side effects. The CIPO-related small intestinal bacterial overgrowth requires treatment preferably via poorly absorbable antibiotics to avoid bacterial resistance. Apart from opioids, which worsen gut motility, analgesics should be considered to manage visceral pain, which might dominate the clinical manifestations. Nutritional support, via modified oral feeding, enteral or parenteral nutrition, is key to halt CIPO-related malnutrition.

EXPERT OPINION

There have been significant roadblocks preventing the development of CIPO treatment. Nonetheless, the considerable advancement in neurogastroenterology and pharmacological agents cast hopes to test the actual efficacy of new prokinetics via well-designed clinical trials. Adequate dietary strategies and supplementation remain of crucial importance. Taken together, novel pharmacological and nutritional options are expected to provide adequate treatments for these patients.

Approach to Disorders of Gut-Brain Interaction

Disorders of gut-brain interaction, previously known as functional gastrointestinal disorders (eg, functional dyspepsia and irritable bowel syndrome), are commonly encountered in both the primary care and gastroenterology clinics. These disorders are often associated with high morbidity and poor patient quality of life and often lead to increased health care use. The management of these disorders can be challenging, as patients often present after having undergone an extensive workup without a definite etiology. In this review, we provide a practical five-step approach to the clinical assessment and management of disorders of gut-brain interaction. The five-step approach includes (1) excluding organic etiologies of the patient's symptoms and using Rome IV criteria for diagnosis, (2) empathizing with the patient to develop trust and a therapeutic relationship, (3) educating the patient about the pathophysiology of these gastrointestinal disorders, (4) expectation setting with a focus on improving function and quality of life, and (5) establishing a treatment plan with central and peripherally acting medications and nonpharmacological modalities. We discuss the pathophysiology of disorders of gut-brain interaction (eg, visceral hypersensitivity), initial assessment and risk stratification, as well as treatment for a variety of diseases with a focus on irritable bowel syndrome and functional dyspepsia.

Irritable bowel syndrome: treatment based on pathophysiology and biomarkers

OBJECTIVE

To appraise the evidence that pathophysiological mechanisms and individualised treatment directed at those mechanisms provide an alternative approach to the treatment of patients with irritable bowel syndrome (IBS).

DESIGN

A PubMED-based literature review of mechanisms and treatment of IBS was conducted independently by the two authors, and any differences of perspective or interpretation of the literature were resolved following discussion.

RESULTS

The availability of several noninvasive clinical tests can appraise the mechanisms responsible for symptom generation in IBS, including rectal evacuation disorders, abnormal transit, visceral hypersensitivity or hypervigilance, bile acid diarrhoea, sugar intolerances, barrier dysfunction, the microbiome, immune activation and chemicals released by the latter mechanism. The basic molecular mechanisms contributing to these pathophysiologies are increasingly recognised, offering opportunities to intervene with medications directed specifically to food components, receptors and potentially the microbiome. Although the evidence supporting interventions for each mechanism is not at the same level of proof, the current state-of-the-art provides the opportunity to advance the practice from treatment based on symptoms to individualisation of treatment guided by pathophysiology and clinically identified biomarkers.

CONCLUSION

These advances augur well for the implementation of evidence-based individualised treatment for patients with IBS based on actionable biomarkers or psychological disturbances.

Update on treatment of abdominal pain in irritable bowel syndrome: A narrative review

The objectives of this narrative review are to update readers on the current state-of-the-art regarding diverse approaches for the treatment of pain, global symptoms, or adequate relief in irritable bowel syndrome (IBS). The article appraises medications, dietary interventions including low fermentable oligosaccharides, disaccharides, and monosaccharides and polyols (FODMAP) diet, fecal microbial transplantation (FMT), electrical approaches, and behavioral therapies including cognitive behavioral therapy (CBT), gut-directed hypnotherapy (GDH), mindfulness, and open-label placebo. Current evidence demonstrates only modest benefit in global IBS symptoms and pain relief. A future approach that identifies pathophysiological mechanisms of IBS through validated biomarkers has the potential to individualize treatment of patients rather than sequential therapeutic trial and error approaches.

The neurobiology of irritable bowel syndrome

Irritable bowel syndrome (IBS) is the most prevalent disorder of brain-gut interactions that affects between 5 and 10% of the general population worldwide. The current symptom criteria restrict the diagnosis to recurrent abdominal pain associated with altered bowel habits, but the majority of patients also report non-painful abdominal discomfort, associated psychiatric conditions (anxiety and depression), as well as other visceral and somatic pain-related symptoms. For decades, IBS was considered an intestinal motility disorder, and more recently a gut disorder. However, based on an extensive body of reported information about central, peripheral mechanisms and genetic factors involved in the pathophysiology of IBS symptoms, a comprehensive disease model of brain-gut-microbiome interactions has emerged, which can explain altered bowel habits, chronic abdominal pain, and psychiatric comorbidities. In this review, we will first describe novel insights into several key components of brain-gut microbiome interactions, starting with reported alterations in the gut connectome and enteric nervous system, and a list of distinct functional and structural brain signatures, and comparing them to the proposed brain alterations in anxiety disorders. We will then point out the emerging correlations between the brain networks with the genomic, gastrointestinal, immune, and gut microbiome-related parameters. We will incorporate this new information into a systems-based disease model of IBS. Finally, we will discuss the implications of such a model for the improved understanding of the disorder and the development of more effective treatment approaches in the future.

Factors associated with lower disease-specific and generic health-related quality of life in Rome IV irritable bowel syndrome

BACKGROUND

Little is known about associations with reduced quality of life in irritable bowel syndrome (IBS) or impact of IBS on quality of life compared with other chronic conditions.

METHODS

We collected demographic, gastrointestinal and psychological symptoms, healthcare usage, direct healthcare costs, impact on work and activities of daily living data from 752 individuals with Rome IV-defined IBS. We used the irritable bowel syndrome quality of life (IBS-QOL) and the EQ-5D-5L questionnaires to examine characteristics associated with lower quality of life.

RESULTS

The mean IBS-QOL among all 752 individuals with Rome IV IBS was 48.4 (SD 22.3) and the mean EQ-5D score was 0.570 (SD 0.283), the latter being comparable to people with stroke, leg ulcers or chronic obstructive pulmonary disease. Lower levels of both disease-specific and generic quality of life were associated with severe IBS symptom scores, abnormal anxiety or depression scores, and higher somatoform symptom-reporting and gastrointestinal symptom-specific anxiety scores (p < 0.001 for all analyses). Those with lower quality of life had significantly higher healthcare usage and direct healthcare costs and more impairment in work and activities of daily living (p < 0.01 for all analyses). Avoidance of alcohol, lower educational level, abnormal anxiety, depression or somatoform symptom-reporting scores, and impairment in social leisure activities, home management or maintaining close relationships were all independently associated with lower quality of life.

CONCLUSION

IBS has a substantial impact on the quality of life of those affected, and worse than observed in some severe chronic organic conditions.

Willingness to pay for medications among patients with Rome IV Irritable Bowel Syndrome

BACKGROUND

Little is known about willingness to pay for medications among individuals with irritable bowel syndrome (IBS).

METHODS

We collected demographic, gastrointestinal symptom, psychological health, quality of life, and healthcare usage data from 752 adults with Rome IV-defined IBS. We examined willingness to pay for a hypothetical medication in return for improvement in IBS symptoms using a contingent valuation method, according to these variables.

RESULTS

The median amount of money individuals was willing to pay was £1-£50 (IQR £0-£100) per month for a medication with a 100% chance of improving IBS symptoms. Women, compared with men, (92.7% willing to pay "£0," 89.8% "£1-£50," 87.3% "£51-£100," 78.9% "£101-£200," and 78.5% "more than £200," p = 0.008) were less likely to be willing to pay for a pill with a 100% chance of improving IBS symptoms whilst those with an annual income of £30,000 or more (12.2% willing to pay "£0," 25.2% "£1-£50," 33.5% "£51-£100," 40.2% "£101-£200," and 35.1% "more than £200," p = 0.002) were more likely. We observed a higher willingness to pay among those with lower IBS-related quality of life (p = 0.002 for trend). Of all 752 individuals, 92.7%, 74.5%, and 58.0% would be willing to pay for a medication that would give them a 100%, 50%, or 30% chance of improving IBS symptoms, respectively.

CONCLUSION

Patients with IBS are willing to pay for medications which improve IBS symptoms. Future studies should investigate the relative importance of medication pricing, efficacy, and side effect profile among individuals with IBS.

Safety and efficacy of purified clinoptilolite-tuff treatment in patients with irritable bowel syndrome with diarrhea: Randomized controlled trial

BACKGROUND

Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder with poor response to treatment. IBS with predominant diarrhea (IBS-D) is accompanied by abdominal pain as well as high stool frequency and urgency. Purified clinoptilolite-tuff (PCT), which is approved by the Food and Drug Administration for use as a dietary supplement with the brand name G-PUR^®, has previously shown therapeutic potential in other indications based on its physical adsorption capacity.

AIM

To assess whether symptoms of IBS-D can be ameliorated by oral treatment with PCT.

METHODS

In this randomized, placebo-controlled, double-blind pilot study, 30 patients with IBS-D diagnosis based on Rome IV criteria were enrolled. Following a 4-wk run-in phase, 14 patients were randomized to receive a 12-wk treatment with G-PUR^® (2 g three times daily), and 16 patients received placebo. The relief from IBS-D symptoms as measured by the proportion of responders according to the Subject’s Global Assessment (SGA) of Relief was assessed as the primary outcome. For the secondary outcomes, validated IBS-D associated symptom questionnaires, exploratory biomarkers and microbiome data were collected.

RESULTS

The proportions of SGA of Relief responders after 12 wk were comparable in both groups, namely 21% in the G-PUR^® group and 25% in the placebo group. After 4 wk of treatment, 36% of patients in the G-PUR^® group vs 0% in the placebo group reported complete or considerable relief. An improvement in daily abdominal pain was noted in 94% vs 83% (P = 0.0353), and the median number of days with diarrhea per week decreased by 2.4 d vs 0.3 d in the G-PUR^® and placebo groups, respectively. Positive trends were observed for 50% of responders in the Bristol Stool Form Scale. Positive trends were also noted for combined abdominal pain and stool consistency response and the Perceived Stress Questionnaire score. Only 64% in the G-PUR^® group compared to 86% in the placebo group required rescue medication intake during the study. Stool microbiome studies showed a minor increase in diversity in the G-PUR^® group but not in the placebo group. No PCT-related serious adverse events were reported.

CONCLUSION

In this randomized, double-blind, placebo-controlled study, the PCT product, G-PUR^®, demonstrated safety and clinical benefit towards some symptoms of IBS-D, representing a promising novel treatment option for these patients.

Immune-mediated food reactions in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder characterized by recurrent abdominal pain and an altered defecation pattern. Depending on the criteria used, it affects between 5 and 10% of the general population and has a serious impact on quality of life. Most patients with IBS show an induction or exacerbation of their symptoms, particularly abdominal pain, after eating certain foods. This raises the question of the role played by food in IBS pathophysiology. In this review, we describe the multiple risk factors of IBS, and we give an overview of the role of food as a trigger of IBS, distinguishing between immune and non-immune reactions to food. We finally highlight recent findings identifying an immune-mediated mechanism underlying food-induced abdominal pain in IBS.

Impact of Rome IV irritable bowel syndrome on work and activities of daily living

BACKGROUND

Few studies have demonstrated the impact of irritable bowel syndrome (IBS) on work and activities of daily living.

METHODS

We collected demographic, gastrointestinal symptom, psychological health and quality of life data from 752 adults with Rome IV-defined IBS. We used the work productivity and activity impairment questionnaire for irritable bowel syndrome and the work and social adjustment scale to examine the degree of both impairment at work and in activities of daily living, as well as factors associated with these.

RESULTS

Of 467 individuals who were employed, 133 (28.5%) reported absenteeism, 373 (85.6%) presenteeism and 382 (81.8%) overall work impairment. A mean of 1.97 hours of work per week was lost due to IBS. Extrapolating this across the entire UK, we estimate that between 72 and 188 million hours of work are lost per year due to IBS in individuals of working age. Among all 752 participants, 684 (91.0%) reported any activity impairment with 220 (29.3%) reporting impairment in home management, 423 (56.3%) in social leisure activities, 207 (27.5%) in private leisure activities, and 203 (27.0%) in maintaining close relationships. Severe IBS, higher levels of anxiety, depression, somatization and gastrointestinal symptom-specific anxiety, and lower levels of IBS-related quality of life were associated with impairment in both work and activities of daily living.

CONCLUSION

Patients with IBS experience a substantial impact on their work and activities of daily living because of their IBS. Future studies should assess the impact of medical interventions on the ability to work and participate in social activities.

Inhibition of Delayed Cerebral Ischemia by Magnesium Is Insufficient for Subarachnoid Hemorrhage Patients: A Network Meta-Analysis

Objective

After subarachnoid hemorrhage, magnesium could reduce the incidence of delayed cerebral ischemia; however, it is still controversial. This study updated the results of recently published magnesium-related studies and conducted an exploratory analysis of the impact of application strategies and intervention factors on the results.

Methods

Public databases were searched from the date of their inception to May 10, 2021. Randomized controlled trials on magnesium agent-related regimens for subarachnoid hemorrhage patients were included.

Results

In total, 28 articles were included in the meta-analysis. For delayed cerebral ischemia, magnesium-related interventions significantly reduced the risk of delayed cerebral ischemia compared with nonmagnesium interventions (odds ratios: 0.40; 95% confidence interval: 0.28–0.56; p < 0.01). For cerebral vasospasm, a random effects model showed that magnesium significantly reduced the risk of cerebral vasospasm (odds ratios: 0.46; 95% confidence interval: 0.33–0.63; p < 0.01). In the subgroup analysis, intracranial magnesium (odds ratios: 6.67; 95% confidence interval: 1.14–38.83; p=0.03) and magnesium plus hydrogen (odds ratios: 10; 95% confidence interval: 1.59–62.73; p=0.01) produced significant results in improving the good recovery rate compared to the control. In the network meta-analysis, magnesium plus nimodipine and simvastatin even showed an effective trend in death/persistent vegetative status improvement.

Conclusion

This study supports the beneficial effect of magnesium in reducing the risk of delayed cerebral ischemia. Based on a single randomized controlled trial, immediate intracranial magnesium therapy with intravenous hydrogen after subarachnoid hemorrhage can increase the good recovery rate. Therefore, more high-quality studies are needed to confirm this finding.

A Systematic Review on the Efficacy and Safety of Selective Serotonin Reuptake Inhibitors in Gastrointestinal Motility Disorders: More Control, Less Risk

Gastrointestinal motility disorders have been thought to occur due to an imbalance in the interaction of the gut-brain axis, which is regulated by serotonin. This recent discovery can be exploited to find newer therapeutic agents such as selective serotonin reuptake inhibitors for functional gastrointestinal disorders.

PubMed, PubMed Central (PMC), and Medline databases were used to obtain the data. Meta-analyses, systematic reviews, randomized control trials, and reviews were included and analyzed in the data.

Of the 19240 studies, 23 were extracted, and after appropriate quality assessment, they were utilized in this systematic review. They included two meta-analyses, four systematic reviews, two randomized control trials, and 15 review articles. The systematic review focuses on the efficacy of selective serotonin reuptake inhibitors (SSRIs) as compared to other treatment modalities for disorders of gut-brain interaction. It explores various studies analyzing SSRIs for their mechanism of action, their desirable effects for treating irritable bowel syndrome, and their tolerability in patients.

SSRIs are effective and safe in treating overall symptoms of gastrointestinal motility disorders, particularly constipation-predominant disorders. They seem to have a better side effect profile than other drugs. This should encourage physicians to prescribe SSRIs early on in the disease.

Amitriptyline at low-dose and titrated for irritable bowel syndrome as second-line treatment (The ATLANTIS trial): protocol for a randomised double-blind placebo-controlled trial in primary care

Background

Irritable bowel syndrome (IBS) is a common functional bowel disorder that has a considerable impact on patient quality of life and substantial societal and health care resource costs. Current treatments are often ineffective. Tricyclic antidepressants have shown promise in secondary care populations but their effectiveness in a primary care setting remains unclear.

Methods

ATLANTIS is a randomised, multi-centre, parallel-group, two-arm, double-blind, placebo-controlled trial of low-dose amitriptyline as a second-line treatment for IBS in primary care. Participants will be invited by letter, or recruited opportunistically, from general practices in three regions of England (West Yorkshire, Wessex, and West of England) and screened for eligibility. A total of 518 adult patients with IBS, who are symptomatic despite first-line therapies, will be randomised 1:1 to amitriptyline or identical placebo for 6 months. Treatment will commence at a dose of 10 mg (or one placebo tablet) daily at night, with dose titration up to a maximum of 30 mg at night, depending on side effects and response to treatment. Participant-reported assessments will be conducted at baseline and 3, 6, and 12 months post-randomisation. The primary objective is to determine the effectiveness of amitriptyline, compared with placebo, in improving participant-reported global symptoms of IBS at 6 months (using the IBS Severity Scoring System). Secondary outcomes include relief of IBS symptoms, effect on IBS-associated somatic symptoms (Patient Health Questionnaire-12), anxiety and depression (Hospital Anxiety and Depression Scale), ability to work and participate in other activities (Work and Social Adjustment Scale), acceptability and tolerability of treatment, self-reported health care use, health-related quality of life (EQ-5D-3L), and cost-effectiveness. A nested, qualitative study will explore patient and general practitioner experiences of treatments and trial participation, including acceptability, adherence, unanticipated effects, and implications for wider use of amitriptyline for IBS in primary care.

Discussion

Determining the clinical and cost-effectiveness of low-dose amitriptyline as a second-line treatment for IBS in primary care will provide robust evidence to inform management decisions.

Trial registration

ISRCTN ISRCTN48075063 . Registered on 7th June 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06492-6.

Direct healthcare costs of Rome IV or Rome III-defined irritable bowel syndrome in the United Kingdom

BACKGROUND

Previous studies have demonstrated a substantial economic impact of irritable bowel syndrome (IBS).

AIMS

To provide contemporaneous estimates of direct healthcare costs of IBS in the United Kingdom.

METHODS

We collected demographic, gastrointestinal and psychological symptoms, quality of life and healthcare usage data from adults with Rome IV or Rome III IBS in the United Kingdom. We calculated the mean annual direct healthcare costs of IBS per person and used contemporaneous IBS prevalence data, together with census data, to estimate annual direct costs of IBS. We also examined predictors of higher costs.

RESULTS

The mean annual direct cost of IBS per person among 752 individuals with Rome IV IBS was £556.65 (SD £1023.92) and £474.16 (SD £897.86) for 995 individuals with Rome III IBS. We estimate the annual direct healthcare cost of IBS in the United Kingdom is £1.27 billion if the Rome IV criteria are used to define IBS, and £2.07 billion using Rome III. Among individuals with Rome IV IBS, mean annual costs were higher in those with opiate use (£907.90 vs £470.58, p < 0.001), more severe symptoms (p < 0.001 for trend), a shorter duration of IBS (1 year, £1227.14 vs >5 years £501.60, p = 0.002), lower quality of life (p < 0.001 for trend), and higher depression, somatisation and gastrointestinal symptom-specific anxiety scores (P < 0.001 for trend for all).

CONCLUSION

We estimate annual direct healthcare costs of IBS of between £1.3 and £2 billion in the United Kingdom.

Adverse events in trials of licensed drugs for irritable bowel syndrome with constipation or diarrhea: Systematic review and meta-analysis

BACKGROUND

Nocebo effects occurring in patients receiving placebo frequently impact on adverse events reported in randomized controlled trials (RCTs) in irritable bowel syndrome (IBS). Therefore, we conducted a systematic review and meta-analysis to assess the proportion of patients randomized to placebo or active drug experiencing any adverse event in trials of licensed drugs for IBS with constipation (IBS-C) or diarrhea (IBS-D), and to estimate the risk of developing adverse events among patients randomized to placebo.

METHODS

We searched MEDLINE, EMBASE CLASSIC and EMBASE, and the Cochrane central register of controlled trials (through June 2021) to identify RCTs comparing licensed drugs with placebo in adults with IBS-C or IBS-D. We generated Forest plots of pooled adverse event rates in both active drug and placebo arms and pooled risk differences (RDs) with 95% confidence intervals (CIs).

KEY RESULTS

There were 21 RCTs of licensed drugs versus placebo in IBS-C (5953 patients placebo) and 17 in IBS-D (3854 patients placebo). Overall, 34.9% and 46.9% of placebo patients in IBS-C and IBS-D trials, respectively, developed at least one adverse event, with a statistically significantly higher risk of any adverse event and withdrawal due to an adverse event with active drug. In IBS-C and IBS-D trials, rates of each individual adverse event were generally higher with active drug. However, in IBS-C trials, only diarrhea or headache was significantly more common with active drug (RD 0.066 (95% CI 0.043-0.088) and RD 0.011 (95% CI 0.002-0.021), respectively), and in IBS-D trials only constipation, nausea, or abdominal pain (RD 0.096 (95% CI 0.054-0.138), 0.014 (95% CI 0.002-0.027), and 0.018 (95% CI 0.002-0.034), respectively).

CONCLUSIONS & INFERENCES

Patients with IBS randomized to placebo have a high risk of reporting adverse events, which might relate to both nocebo and non-nocebo factors. Although patients' expectations and psychosocial factors may be involved, further understanding of the mechanisms are important to control or optimize these effects in RCTs, as well as in clinical practice.

Efficacy of a low FODMAP diet in irritable bowel syndrome: systematic review and network meta-analysis

OBJECTIVE

A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) is recommended for irritable bowel syndrome (IBS), if general lifestyle and dietary advice fails. However, although the impact of a low FODMAP diet on individual IBS symptoms has been examined in some randomised controlled trials (RCTs), there has been no recent systematic assessment, and individual trials have studied numerous alternative or control interventions, meaning the best comparator is unclear. We performed a network meta-analysis addressing these uncertainties.

DESIGN

We searched the medical literature through to 2 April 2021 to identify RCTs of a low FODMAP diet in IBS. Efficacy was judged using dichotomous assessment of improvement in global IBS symptoms or improvement in individual IBS symptoms, including abdominal pain, abdominal bloating or distension, and bowel habit. Data were pooled using a random effects model, with efficacy reported as pooled relative risks (RRs) with 95% CIs, and interventions ranked according to their P-score.

RESULTS

We identified 13 eligible RCTs (944 patients). Based on failure to achieve an improvement in global IBS symptoms, a low FODMAP diet ranked first vs habitual diet (RR of symptoms not improving=0.67; 95% CI 0.48 to 0.91, P-score=0.99), and was superior to all other interventions. Low FODMAP diet ranked first for abdominal pain severity, abdominal bloating or distension severity and bowel habit, although for the latter it was not superior to any other intervention. A low FODMAP diet was superior to British Dietetic Association (BDA)/National Institute for Health and Care Excellence (NICE) dietary advice for abdominal bloating or distension (RR=0.72; 95% CI 0.55 to 0.94). BDA/NICE dietary advice was not superior to any other intervention in any analysis.

CONCLUSION

In a network analysis, low FODMAP diet ranked first for all endpoints studied. However, most trials were based in secondary or tertiary care and did not study effects of FODMAP reintroduction and personalisation on symptoms.

AGA Clinical Practice Update on the Role of Diet in Irritable Bowel Syndrome: Expert Review

DESCRIPTION

Irritable bowel syndrome (IBS) is a commonly diagnosed gastrointestinal disorder that can have a substantial impact on quality of life. Most patients with IBS associate their gastrointestinal symptoms with eating food. Mounting evidence supports dietary modifications, such as the low-fermentable oligo-, di-, and monosaccharides and polyols (FODMAP) diet, as a primary treatment for IBS symptoms. The aim of this American Gastroenterological Association (AGA) Clinical Practice Update (CPU) is to provide best practice advice statements, primarily to clinical gastroenterologists, covering the role of diet in IBS treatment.

METHODS

This expert review was commissioned and approved by the AGA CPU Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the CPU Committee and external peer review through standard procedures of Gastroenterology. The best practice advice statements were drawn from reviewing existing literature combined with expert opinion to provide practical advice on the role of diet in treating patients with IBS. Because this was not a systematic review, formal rating of the quality of evidence or strength of the presented considerations was not performed. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Dietary advice is ideally prescribed to patients with IBS who have insight into their meal-related gastrointestinal symptoms and are motivated to make the necessary changes. To optimize the quality of teaching and clinical response, referral to a registered dietitian nutritionist (RDN) should be made to patients who are willing to collaborate with a RDN and patients who are not able to implement beneficial dietary changes on their own. If a gastrointestinal RDN is not available, other resources can assist with implementation of diet interventions. BEST PRACTICE ADVICE 2: Patients with IBS who are poor candidates for restrictive diet interventions include those consuming few culprit foods, those at risk for malnutrition, those who are food insecure, and those with an eating disorder or uncontrolled psychiatric disorder. Routine screening for disordered eating or eating disorders by careful dietary history is critical because they are common and often overlooked in gastrointestinal conditions. BEST PRACTICE ADVICE 3: Specific diet interventions should be attempted for a predetermined length of time. If there is no clinical response, the diet intervention should be abandoned for another treatment alternative, for example, a different diet, medication, or other form of therapy. BEST PRACTICE ADVICE 4: In preparation for a visit with a RDN, patients should provide dietary information that will assist in developing an individualized nutrition care plan. BEST PRACTICE ADVICE 5: Soluble fiber is efficacious in treating global symptoms of IBS. BEST PRACTICE ADVICE 6: The low-FODMAP diet is currently the most evidence-based diet intervention for IBS. Healthy eating advice as described by the National Institute of Health and Care Excellence Guidelines, among others, also offers benefit to a subset of patients with IBS. BEST PRACTICE ADVICE 7: The low-FODMAP diet consists of the following 3 phases: 1) restriction (lasting no more than 4-6 weeks), 2) reintroduction of FODMAP foods, and 3) personalization based on results from reintroduction. BEST PRACTICE ADVICE 8: Although observational studies found that most patients with IBS improve with a gluten-free diet, randomized controlled trials have yielded mixed results. BEST PRACTICE ADVICE 9: There are limited data showing that selected biomarkers can predict response to diet interventions in patients with IBS, but there is insufficient evidence to support their routine use in clinical practice.

Current evidence on the therapeutic use of fiber in irritable bowel syndrome

INTRODUCTION

Patients with irritable bowel syndrome (IBS) frequently resort to natural products, or request doctors to prescribe them, to relieve their symptoms, due to the poor efficacy and tolerability of several traditional drugs. Products containing fiber are among the most used and their clinical efficacy is discussed here based on the most recent scientific evidence.

AREAS COVERED

A literature search was carried out to identify the most significant publications in order to deal with the topics of the general characteristics of fibers and the scientific evidence underlying their therapeutic use, the properties of ispaghula husk and the mechanisms by which this product carries out its therapeutic actions.

EXPERT OPINION

The most recent clinical guidelines on the management of IBS consider ispaghula husk, a product containing soluble fiber, as a reasonable first line therapy for IBS patients with symptoms. In contrast, products containing insoluble fibers, particularly wheat bran, do not appear to be useful in treating IBS symptoms. The clinical data on the use of prebiotics in IBS are still inconclusive. However, low daily amounts of fructo-oligosaccharides or β-galacto-oligosaccharides (also known as trans-galacto-oligosaccharides) may be effective in improving IBS symptoms; further trials are needed to definitively establish their clinical usefulness.

Effectiveness of cell- and colony stimulating factor-based therapy for liver cirrhosis: a network meta-analysis of randomized controlled trials

BACKGROUND AIMS

Cirrhosis is the 11th leading cause of death worldwide. Because of the limitations of liver transplantation, cell- and granulocyte colony-stimulating factor (G-CSF)-based therapies are considered potential treatment methods. This work analyzes the effectiveness of cell- and G-CSF-based therapies by network meta-analysis.

METHODS

A literature search was performed in four databases from inception to September 10, 2021. Registered randomized controlled trials (RCTs) evaluating cell-based therapies and/or G-CSF-based therapies for cirrhosis patients were included. Traditional and network meta-analyses were analyzed in terms of survival, model for end-stage liver disease (MELD) score, Child-Turcotte-Pugh (CTP) score, alanine aminotransferase levels and aspartate aminotransferase levels.

RESULTS

Twenty-four studies were included in this analysis. The results showed that G-CSF-based therapies (odds ratio [OR], 2.38, 95% confidence interval [CI], 1.49-3.79, P < 0.01) and cell-based therapies (OR, 1.54, 95% CI, 1.00-2.40, P = 0.048) improved the transplantation-free survival rate compared with standard medical treatment. Network analysis results showed that G-CSF combined with erythropoietin (EPO) and growth hormone (GH) had a therapeutic advantage, and cell-based therapy with mononuclear cell (MNC) hepatic artery injection and intravenous mesenchymal stem cells (MSCs) combined with G-CSF also had a relative advantage in terms of survival outcome. For the MELD score, G-CSF plus GH and MSC portal vein injection had relative advantages. G-CSF plus GH and G-CSF plus EPO had advantages in terms of CTP scores. The included strategies demonstrated no obvious improvement in liver injury indicators.

CONCLUSIONS

Cell-based therapy has potential therapeutic effects for liver cirrhosis. Among cell-based therapies, intravenous MSCs and hepatic artery injection of MNCs have advantageous therapeutic effects. The use of G-CSF was also noted in regimens that improved survival outcomes. However, more well-designed, large-scale RCTs are needed to confirm this conclusion.

Willingness to accept risk with medication in return for cure of symptoms among patients with Rome IV irritable bowel syndrome

BACKGROUND

Some drugs for irritable bowel syndrome (IBS) have serious side effects.

AIMS

To examine the willingness of individuals with IBS to accept risks with medication in return for symptom cure.

METHODS

We collected demographic, gastrointestinal symptoms, psychological health, quality of life and impact on work and daily activities data from 752 adults with Rome IV-defined IBS. We examined median willingness to accept death in return for cure with a hypothetical medication using a standard gamble, according to these variables.

RESULTS

Participants would accept a median 2.0% (IQR 0.0%-9.0%) risk of death in return for a 98.0% (IQR 91.0%-100.0%) chance of permanent symptom cure. The median accepted risk of death was higher in men (5.0% vs 2.0%, P < 0.001), those with continuous abdominal pain (4.0% vs 1.0%, P < 0.001), more severe symptoms (P = 0.005 for trend), abnormal depression scores (P < 0.001 for trend), higher gastrointestinal symptom-specific anxiety (P < 0.001 for trend), and lower IBS-related quality of life (P < 0.001 for trend). Those willing to accept above median risk of death were more likely to be male (17.1% vs 9.1%, P < 0.001), take higher levels of risks in their daily life (P = 0.008 for trend), and report continuous abdominal pain (53.1% vs 39.4%, P < 0.001), and had higher depression (P = 0.004 for trend) and lower quality of life (P < 0.001 for trend) scores.

CONCLUSION

Patients are willing to accept significant risks in return for cure of their IBS symptoms.

Placebo Response Rates in Trials of Licensed Drugs for Irritable Bowel Syndrome With Constipation or Diarrhea: Meta-analysis

BACKGROUND & AIMS

There are several licensed drugs for irritable bowel syndrome (IBS) that have proven efficacy in randomized controlled trials (RCTs), but placebo response rates are high. We conducted a systematic review and meta-analysis of licensed drugs to estimate magnitude of placebo response rate according to Food and Drug Administration (FDA)-recommended endpoints and to assess how this varies with stringency of the endpoint used to define response.

METHODS

We searched MEDLINE, EMBASE CLASSIC and EMBASE, and the Cochrane central register of controlled trials (through January 2021) to identify RCTs comparing licensed drugs with placebo in adult IBS patients. Studies assessed efficacy according to at least one of composite response, abdominal pain response, or stool response. Data were extracted as intention-to-treat analyses, with dropouts assumed to be treatment failures and pooled using a random-effects model.

RESULTS

There were 17 RCTs of licensed drugs versus placebo in IBS with constipation (4603 patients placebo) and 17 trials in IBS with diarrhea (3908 patients placebo). In IBS with constipation, according to FDA criteria, pooled composite, abdominal pain, and stool response rates with placebo over ≥6 of 12 weeks were 18.9%, 34.6%, and 30.1%, respectively. Evaluating response rates over ≥9 of 12 weeks led to placebo response rates of 4.3% for the composite endpoint, 24.5% for abdominal pain, and 7.7% for stool. In IBS with diarrhea, pooled placebo response rates according to FDA criteria were 16.2% for the composite endpoint, 40.2% for abdominal pain, and 16.2% for stool. Increasing the threshold used to define abdominal pain response from ≥30% improvement to ≥40% or ≥50% led to lower placebo response rates of 34.5% and 23.4%.

CONCLUSIONS

Future RCTs should adhere to current FDA-recommended endpoints for IBS because these lead to lower placebo response rates. However, consideration should be given to further refining some of these to better differentiate between active drug and placebo.

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.

Irritable bowel syndrome and microbiome; Switching from conventional diagnosis and therapies to personalized interventions

The human microbiome has been linked to several diseases. Gastrointestinal diseases are still one of the most prominent area of study in host-microbiome interactions however the underlying microbial mechanisms in these disorders are not fully established. Irritable bowel syndrome (IBS) remains as one of the prominent disorders with significant changes in the gut microbiome composition and without definitive treatment. IBS has a severe impact on socio-economic and patient’s lifestyle. The association studies between the IBS and microbiome have shed a light on relevance of microbial composition, and hence microbiome-based trials were designed. However, there are no clear evidence of potential treatment for IBS. This review summarizes the epidemiology and socioeconomic impact of IBS and then focus on microbiome observational and clinical trials. At the end, we propose a new perspective on using data-driven approach and applying computational modelling and machine learning to design microbiome-aware personalized treatment for IBS.

Belgian consensus on irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is characterised by recurrent abdominal pain related to defaecation or associated with altered stool frequency or consistency. Despite its prevalence, major uncertainties in the diagnostic and therapeutic management persist in clinical practice.

METHODS

A Delphi consensus was conducted by 20 experts from Belgium, and consisted of literature review and voting process on 78 statements. Grading of recommendations, assessment, development and evaluation criteria were applied to evaluate the quality of evidence. Consensus was defined as > 80 % agreement.

RESULTS

Consensus was reached for 50 statements. The Belgian consensus agreed as to the multifactorial aetiology of IBS. According to the consensus abdominal discomfort also represents a cardinal symptom, while bloating and abdominal distension often coexist. IBS needs subtyping based on stool pattern. The importance of a positive diagnosis, relying on history and clinical examination is underlined, while additional testing should remain limited, except when alarm features are present. Explanation of IBS represents a crucial part of patient management. Lifestyle modification, spasmolytics and water-solube fibres are considered first-line agents. The low FODMAP diet, selected probiotics, cognitive behavioural therapy and specific treatments targeting diarrhoea and constipation are considered appropriate. There is a consensus to restrict faecal microbiota transplantation and gluten-free diet, while other treatments are strongly discouraged.

CONCLUSIONS

A panel of Belgian gastroenterologists summarised the current evidence on the aetiology, symptoms, diagnosis and treatment of IBS with attention for the specificities of the Belgian healthcare system.

Peppermint oil effects on the gut microbiome in children with functional abdominal pain

Peppermint oil (PMO) is effective in the treatment of functional abdominal pain disorders, but its mechanism of action is unclear. Evidence suggests PMO has microbicidal activity. We investigated the effect of three different doses of PMO on gut microbiome composition. Thirty children (7-12 years of age) with functional abdominal pain provided a baseline stool sample prior to randomization to 180, 360, or 540 mg of enteric coated PMO (10 participants per dose). They took their respective dose of PMO (180 mg once, 180 mg twice, or 180 mg thrice daily) for 1 week, after which the stool collection was repeated. Baseline and post-PMO stools were analyzed for microbiome composition. There was no difference in alpha diversity of the gut microbiome between the baseline and post-PMO treatment. Principal coordinate analysis revealed no significant difference in overall bacterial composition between baseline and post-PMO samples, as well as between the PMO dose groups. However, the very low abundant Collinsella genus and three operational taxonomic units (one belonging to Collinsella) were significantly different in samples before and after PMO treatment. The Firmicutes/Bacteroidetes ratio was lower in children who received 540 mg of PMO compared to the 180 mg and 360 mg dose groups (p = 0.04). Network analysis revealed separation between pre- and post-PMO fecal samples with the genus Collinsella driving the post-PMO clusters. PMO administration appeared to impact only low abundance bacteria. The 540 mg PMO dose differentially impacted the Firmicutes/Bacteroidetes ratio. A higher dose and/or longer duration of treatment might yield different results.

Improvement in constipation and diarrhea is associated with improved abdominal pain in patients with functional bowel disorders

BACKGROUND

Abdominal pain is a bothersome and lifestyle limiting symptom in patients with functional bowel disorders. It is associated with decreased quality of life in affected individuals, as well as significant annual healthcare expenditure. Knowledge of specific factors that predict improvement in abdominal pain in those with functional bowel disorders is thus far limited.

METHODS

Consecutive patients presenting for outpatient care at a major academic medical center between October 2017 and March 2020 completed an electronic symptom survey prior to initial clinic visit, and again after 3 months. The Rome IV questionnaires for functional dyspepsia, irritable bowel syndrome, functional constipation, and functional diarrhea were all included. Additionally, all subjects completed the Patient Reported Outcomes Measurement Information System Anxiety, Depression, and sleep disturbance questionnaires. Patients with a diagnosis of a Rome IV functional gastrointestinal disorder without any organic cause for symptoms were identified based on both chart review as well as survey response data. Univariable and multivariable analysis was used to assess predictors of improved abdominal pain after 3 months.

KEY RESULTS

180 patients with a mean age of 45.3 years were included in the final analysis. 78.3% of patients were female, and 77.2% met Rome IV criteria for irritable bowel syndrome. On multivariable analysis, improvement in constipation and diarrhea were both independent predictors of improved abdominal pain after 3 months.

CONCLUSIONS AND INFERENCES

Improvement in constipation and diarrhea both predicted improvement in abdominal pain, suggesting that addressing these factors is central to the management of abdominal pain in functional gastrointestinal disorders.

Eluxadoline Versus Antispasmodics in the Treatment of Irritable Bowel Syndrome: An Adjusted Indirect Treatment Comparison Meta-analysis

Objective: Eluxadoline is a newly approved drug for irritable bowel syndrome (IBS), but it has rarely been compared with positive controls. We aimed to compare eluxadoline with antispasmodics in the treatment of IBS.

Methods: We searched the OVID Medline, Embase, and the Cochrane Central Register of Controlled Trials databases for randomized controlled trials (RCTs) comparing eluxadoline or antispasmodics with placebo. The search was conducted from 1 January 1980, to 1 September 2020, without any language restrictions. The primary efficacy outcome was the relief of abdominal pain, defined by a reduction of pain scores of at least 30% from baseline. The secondary efficacy outcome was the relief of global IBS symptoms, defined by a composite response of a decrease in abdominal pain and improvement in stool consistency on the same day for at least 50% of the days assessed. The data were pooled using a random-effects model. Outcome estimates were pooled by using Risk Ratios (RRs) and P-scores.

Results: Forty-two trials with 8,457 participants were included from 45 articles. Compared with placebo, each of drotaverine, pinaverium, alverine combined with simethicone (ACS) and eluxadoline 100 mg was highly effective in the relief of abdominal pain, with drotaverine [RR, 2.71 (95% CI, 1.70 to 4.32), P-score = 0.95] ranking first. Drotaverine, otilonium, cimetropium, pinaverium, and eluxadoline 100 mg had significantly high the relief of global IBS symptomss, for which drotaverine [RR, 2.45 (95% CI, 1.42 to 4.22), P-score = 0.95] was ranked first. No significant difference was found between these interventions. Pinaverium had a significantly higher the relief of global IBS symptoms than eluxadoline [RR, 1.72 (95% CI, 1.33 to 2.21)] on sensitivity analysis. However, no significant difference was found in the number of adverse events between each intervention and the placebo.

Conclusion: Our network meta-analysis showed that eluxadoline 100 mg was at least as effective as antispasmodics in relieving abdominal pain in IBS. But eluxadoline had more reported adverse events. Antispasmodics are still the first choice for the treatment of IBS.