Systematic review: the prevalence of idiopathic bile acid malabsorption as diagnosed by SeHCAT scanning in patients with diarrhoea-predominant irritable bowel syndrome

Real-world experience with the diagnosis of bile acid malabsorption (BAM) using serum 7-alpha-C4 and 48-hour stool bile acids

INTRODUCTION AND AIMS

Bile acid malabsorption (BAM) is responsible for 30% of cases of diarrhea-predominant irritable bowel syndrome (IBS-D) or functional diarrhea and 63.5% of cases of diarrhea following cholecystectomy. 75SeHCAT is the gold standard diagnostic method but is unavailable in Mexico. Alternatively, primary bile acid (PBA) and total bile acid (TBA) determination in 48 h stools and 7αC4 measurement have been proposed as screening tests.

OBJECTIVE

Our aim was to evaluate the experience with PBAs and/or TBAs and to determine whether 7αC4 is a good screening biomarker for BAM in clinical practice.

MATERIAL AND METHODS

An ambispective study of patients with chronic diarrhea was conducted. BAM was considered present with 7αC4 > 55 ng/mL (cost $420.00 USD), PBAs ≥ 9.8%, TBAs > 2,337 μmol/48 h, or TBAs > 1,000 μmol/48 h + PBAs > 4% (TBAs + PBAs) ($405.00 USD). However, those tests must be shipped to the US for their analysis (total cost $825.00 USD). Data were compared using the chi-square test and Student's t test, and Spearman's Rho correlations were calculated.

RESULTS

We analyzed 48 patients with 7αC4 (age: 58.4 ± 16.9, women: 54.2%). BAM was confirmed by 7αC4 in 12.5%, by PBAs in 38.9%; by TBAs in 5.5%, and by TBAs + PBAs in 16.7%. We found elevated 7αC4 in patients with high or normal PBA/TBA levels (correlation with TBAs: 0.542, p = 0.020; PBAs: -0.127, p = 0.605; TBAs + PBAs: -0.200, p = 0.426). Lastly, BAM identified by 7αC4 was more frequent in patients with previous cholecystectomy (22.7%) vs. those without (3.8%).

CONCLUSIONS

Our study confirms that 7αC4 correlates well with TBAs and is a good biomarker for BAM screening because it can be elevated, despite normal PBA/TBA levels. Additionally, it represents a 49% cost savings in BAM investigation.

British Society of Gastroenterology practice guidance on the management of acute and chronic gastrointestinal symptoms and complications as a result of treatment for cancer

BACKGROUND

Survival rates after a diagnosis of cancer are improving. Poorly managed gastrointestinal (GI) side effects can interfere with delivery of curative cancer treatment. Long-term physical side effects of cancer therapy impinge on quality of life in up to 25% of those treated for cancer, and GI side effects are the most common and troublesome.

AIM

To provide comprehensive, practical guidance on the management of acute and chronic luminal gastrointestinal symptoms arising during and after treatment for cancer METHODS: A multidisciplinary expert group including patients treated for cancer, divided into working parties to identify, and synthesise recommendations for the optimal assessment, diagnosis and appropriate interventions for luminal GI side effects of systemic and local cancer therapies. Recommendations were developed using the principles of the BMJ AGREE II reporting.

RESULTS

103 recommendations were agreed. The importance of the patient perspective and what can be done to support patients are emphasised. Key physiological principles underlying the development of GI toxicity arising from cancer therapy are outlined. Individual symptoms or symptom clusters are poor at distinguishing the underlying cause(s), and investigations are required if empirical therapy does not lead rapidly to significant benefits. Patients frequently have multiple GI causes for symptoms; all need to be diagnosed and optimally treated to achieve resolution. Investigations and management approaches now known to be ineffective or of questionable benefit are highlighted.

CONCLUSIONS

The physical, emotional and financial costs to individuals, their families and society from cancer therapy can be considerable. Identifying and signposting affected patients who require specialist services is the role of all clinicians. Progress in the treatment of cancer increasingly means that patients require expert, multidisciplinary supportive care providing effective and safe treatment at every stage of the cancer journey. Development of such expertise should be prioritised as should the education of health professionals and the public in what, when and how acute and chronic gastrointestinal symptoms and complications should be managed.

Diet therapy (The 8×5 Diet) for adults living with bile acid diarrhoea: protocol for a feasibility randomised controlled trial

INTRODUCTION

A national research priority for people living with bile acid diarrhoea (BAD) is effective treatment options to improve their quality of life. This study aims to evaluate the feasibility of conducting a randomised controlled trial (RCT) of a novel healthy dietary pattern (The 8×5 Diet) to inform a future, larger trial.

METHODS AND ANALYSIS

We plan to enrol 76 UK adults living with BAD and ongoing diarrhoea using self-selection sampling and digital technologies. Eligible participants will be assigned to groups using permuted block randomisation using 1:1 allocation to receive either 8 weeks of usual care or The 8×5 Diet using one-to-one, dietitian counselling via a video-conferencing platform and developed digital resources. Randomisation, consent, recruitment, retention and acceptability will be evaluated using data from the RCT and post-trial interviews conducted with those in the intervention group. Secondary outcome exploratory assessment will include health-related quality of life, symptom relief, diarrhoea, diet quality, nutrient intakes and diet satisfaction.

ETHICS AND DISSEMINATION

Ethical approval was granted by the University of Manchester Research Ethics Committee (2024-19094-33261; V1.7, last updated: 24/02/2025).Findings will be disseminated through peer-reviewed publication, conference presentation and social media.

TRIAL REGISTRATION NUMBER

NCT06259396.

Involvement of bile acid in diarrhoea and therapeutic effect of colestimide in hereditary ATTR amyloidosis

BACKGROUND

Diarrhoea is one of the most serious complications in hereditary ATTR (ATTRv) amyloidosis. However, its precise pathomechanism remains unknown. The present study investigated the involvement of bile acid in diarrhoea along with the therapeutic effect of colestimide, a bile acid sequestrant, in ATTRv amyloidosis.

METHODS

We prospectively enrolled 19 ATTRv amyloidosis patients (9 with refractory diarrhoea and 10 without diarrhoea) and 20 healthy individuals for measurements of serum 7a-hydroxy-4-cholesten-3-one (C4) levels. The patients with diarrhoea were then treated with oral colestimide (1.5 g twice daily) for 28 days. The frequency of diarrhoea and C4 level were evaluated before and after colestimide treatment.

RESULTS

Mean serum C4 level was significantly higher in ATTRv patients with diarrhoea (62.3 ng/mL) than in ATTRv patients without diarrhoea (24.0 ng/mL, p = 0.03). Colestimide treatment significantly decreased mean diarrhoea frequency (pre-treatment period: 9.1 times/week, colestimide treatment period, 6.6 times/week, p = 0.04) and increased mean C4 level (before treatment: 66.2 ng/mL, after treatment: 187.1 ng/mL, p = 0.02).

CONCLUSIONS

Bile acid status was significantly associated with diarrhoea in ATTRv amyloidosis. Colestimide and other bile acid sequestrants may reduce diarrhoea frequency in afflicted patients.

Bile acid diarrhea in patients with chronic diarrhea. Current appraisal and recommendations for clinical practice

Bile Acid Diarrhea (BAD) is a common cause of chronic diarrhea, often accompanied by urgency, occasional fecal incontinence, abdominal pain, and fatigue. A nationwide survey has shown limited awareness of BAD within the Italian medical community, prompting a panel of experts to develop a Position Paper that outlines the most practical and cost-saving diagnostic investigations and treatments for this frequently overlooked condition. The document provides an overview of the epidemiology, pathophysiology, clinical manifestations, and classification of the different types of Bile Acid Diarrhea (BAD). A key focus is the diagnostic approach to identifying and managing the many undiagnosed BAD patients in both primary care and specialized medical settings. Finally, the paper addresses the optimal therapeutic strategies for BAD, including traditional bile acid sequestrants and newer, promising treatments.

Treatment of Bile Acid Diarrhea With Glucagon-Like Peptide 1 Receptor Agonists: A Promising Yet Understudied Approach

Bile acid diarrhea (BAD) is a chronic and socially debilitating disease characterized by abdominal pain, diarrhea, urgency, and fecal incontinence. Recently, in a 6-week randomized controlled trial, we showed that the glucagon-like peptide 1 receptor agonist (GLP-1RA) liraglutide is superior to bile acid sequestration (considered standard-of-care) using colesevelam in reducing BAD symptoms. The emergence of new, more potent, and longer-acting GLP-1RAs has spurred an interest in these treatments in BAD management. Here, we review the literature on different GLP-1RAs in BAD treatment and outline their potential mode of actions, highlight knowledge gaps, and outline the need for further clinical evidence generation.

Development and validation of a novel 7α-hydroxy-4-cholesten-3-one (C4) liquid chromatography tandem mass spectrometry method and its utility to assess pre-analytical stability

OBJECTIVES

7α-Hydroxy-4-cholesten-3-one (C4) is the common intermediary of both primary bile acids. C4 is recommended by the British Society of Gastroenterology for the investigation of bile acid diarrhoea (BAD) in patients with chronic diarrhoea. This project aimed to develop and validate an assay to quantitate C4 in serum and assess the stability of C4 in unseparated blood.

METHODS

Accuracy was underpinned by calibrating to quantitative nuclear magnetic resonance analysis. C4 was analysed in a 96-well plate format with a deuterated C4 internal standard and liquid-liquid extraction. Validation followed the 2018 Food and Drug Administration guidelines. To assess C4 stability, healthy volunteers (n=12) donated 8 fasted samples each. Samples were incubated at 20 °C for up to 72 h and retrieved, centrifuged, aliquoted and frozen for storage at different time points prior to C4 analysis.

RESULTS

The C4 method demonstrated excellent analytical performance and passed all validation criteria. The method was found to be accurate, precise, free from matrix effects and interference. After 72 h of delayed sample separation, C4 concentration gradually declined by up to 14 % from baseline. However, the change was not significant for up to 12 h.

CONCLUSIONS

We present a robust method of analysing serum C4, offering a convenient alternative to 75SeHCAT for BAD investigation. C4 was found to decline in unseparated blood over time; however, after 12 h the mean change was <5 % from baseline. Our results suggest C4 is suitable for collection from both primary and secondary care prior to gastroenterology referral.

An evidence-based update on the diagnosis and management of irritable bowel syndrome

INTRODUCTION

Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction affecting 5% of the population. The cardinal symptoms are abdominal pain and altered stool form or frequency.

AREAS COVERED

Diagnosis and management of IBS. We searched the literature for diagnostic accuracy studies, randomized controlled trials, and meta-analyses. A positive diagnosis of IBS, alongside testing to exclude celiac disease, is recommended. Exhaustive investigation has a low yield. Patients should be offered traditional dietary advice. If response is incomplete, specialist dietetic guidance should be considered. Probiotics may be beneficial, but quality of evidence is poor. First-line treatment of constipation is with laxatives, with secretagogues used where these are ineffective. Anti-diarrheal drugs should be used first-line for diarrhea, with second-line drugs including 5-hydroxytryptamine-3 antagonists, eluxadoline, or rifaximin, where available. First-line treatment of abdominal pain should be with antispasmodics, with gut-brain neuromodulators prescribed second-line. Low-dose tricyclic antidepressants, such as amitriptyline, are preferred. Brain-gut behavioral therapies are effective and have evidence for efficacy in patients refractory to standard therapies.

EXPERT OPINION

Despite substantial advances, there remains scope for improvement in terms of both the diagnosis and management of IBS. Reinforcement of positive diagnostic strategies for the condition and novel treatment paradigms are required.

Validating Simple Modifications to the Rome IV Criteria for the Diagnosis of Irritable Bowel Syndrome in Secondary Care

BACKGROUND

The Rome IV criteria for irritable bowel syndrome (IBS) may be too restrictive for clinical practice and research.

AIMS

To validate the Rome IV criteria and study the diagnostic performance of simple modifications to them.

METHODS

We collected symptom data from consecutive adults with suspected IBS seen in a single clinic. We used a reference standard to confirm IBS (presence of lower abdominal pain associated with altered stool form or frequency; no evidence of organic gastrointestinal disease after limited investigation). We applied Rome IV criteria, but also two modifications. First, we re-incorporated abdominal discomfort but kept symptom frequency required for both abdominal pain and discomfort to at least 1 day per week. Second, we included only abdominal pain but relaxed symptom frequency back to 3 days per month. We calculated sensitivity, specificity and positive and negative likelihood ratios (LRs), with 95% confidence intervals (CIs), for each diagnostic criterion.

RESULTS

We recruited 170 patients (76.5% female, mean age 37.9 years). Sensitivity and specificity of the Rome IV criteria were 82.1% and 85.1%, respectively; positive and negative LRs were 5.51 (95% CI 2.95-11.3) and 0.21 (95% CI 0.14-0.31), respectively. Modifying the criteria by relaxing the frequency of abdominal pain to 3 days per month led to the best performance [sensitivity 90.2%, specificity 85.1%, positive LR 6.06 (95% CI 3.25-12.2), and negative LR 0.11 (95% CI 0.07-0.19)].

CONCLUSIONS

The Rome IV criteria performed well in diagnosing IBS. A simple modification relaxing the required frequency of abdominal pain improved their performance.

Liraglutide and Colesevelam Change Serum and Fecal Bile Acid Levels in a Randomized Trial With Patients With Bile Acid Diarrhea

INTRODUCTION

Both liraglutide and colesevelam improve bile acid diarrhea symptoms. Colesevelam binds excess amounts of diarrhea-causing bile acids in the colon, whereas the mode of action for liraglutide remains elusive. In this article, we examined the impact of colesevelam and liraglutide treatment on the concentrations of bile acids in serum and feces and the fecal microbiota composition to better understand the 2 drugs' modes of action.

METHODS

Bile acid species were analyzed in serum and fecal samples from a randomized, double-blind, double-dummy trial at baseline and after 3 and 6 weeks of orally administered colesevelam (1,875 mg twice daily, n = 26) or subcutaneously administered liraglutide (uptitrated by weekly increments of 0.6 mg from 0.6 to 1.8 mg daily, n = 26) in patients with 75 selenium-homotaurocholic acid test-verified, idiopathic, or postcholecystectomy bile acid diarrhea. Fecal microbiota composition was analyzed by 16S rRNA gene amplicon sequencing at the same time points.

RESULTS

Colesevelam increased the fecal concentrations of all bile acid species, whereas it decreased serum concentrations of secondary bile acids. Liraglutide induced a small increase in serum unconjugated bile acid concentrations without affecting fecal bile acid concentrations. No changes in fecal microbiota composition were observed with either treatment.

DISCUSSION

Colesevelam and liraglutide exhibit distinct effects on serum and fecal bile acid concentrations with colesevelam reducing serum concentrations of secondary bile acids and promoting fecal bile acid excretion, whereas liraglutide enhances serum concentrations of unconjugated bile acids, potentially through deceleration of small intestinal transit time allowing more time for passive absorption of bile acids.

Advances in the pathophysiology, diagnosis and management of chronic diarrhoea from bile acid malabsorption: a systematic review

Bile acid malabsorption (BAM) is an important disorder of digestive pathophysiology as it generates chronic diarrhoea. This condition originates from intricate pathways involving bile acid synthesis and metabolism in the liver and gut, the composition of gut microbiota, enterohepatic circulation and key receptors as farnesoid X receptor (FXR), fibroblast growth factor receptor 4 (FGFR4), and the G-protein bile acid receptor-1 (GPBAR-1). Although symptoms can resemble those related to disorders of gut brain interaction, accurate diagnosis of BAM may greatly benefit the patient. The empiric diagnosis of BAM is primarily based on the clinical response to bile acid sequestrants. Specific tests including the 48-hour fecal bile acid test, serum levels of 7α-hydroxy-4-cholesten-3-one (C4) and fibroblast growth factor 19 (FGF19), and the 75Selenium HomotauroCholic Acid Test (SeHCAT) are not widely available. Nevertheless, lack of diagnostic standardization of BAM may account for poor recognition and delayed management. Beyond bile acid sequestrants, therapeutic approaches include the use of FXR agonists, FGF19 analogues, glucagon-like peptide-1 (GLP-1) receptor agonists, and microbiota modulation. These novel agents can best make their foray into the therapeutic armamentarium if BAM does not remain a diagnosis of exclusion. Ignoring BAM as a specific condition may continue to contribute to increased healthcare costs and reduced quality of life. Here, we aim to provide a comprehensive review of the pathophysiology, diagnosis, and management of BAM.

Bile Acid Diarrhea Is Associated With an Increased Incidence of Gastrointestinal Cancers

INTRODUCTION

Bile acid diarrhea (BAD) is an underrecognized and socially debilitating disease caused by high concentrations of bile acids in the colon. Bile acids directly and indirectly promote carcinogenesis. In this article, we investigated whether individuals with BAD have an increased risk of gastrointestinal (GI) cancers.

METHODS

By using the Danish health registries, adult individuals with BAD were identified by International Classification of Diseases 10th revision code K90.8 or referral to the diagnostic ⁷⁵selenium-homotaurocholic acid test followed by prescription of a bile acid sequestrant within 365 days (n = 5,245). Age- and sex-matched individuals without BAD were included for comparison (n = 52,450). We analyzed the cumulative incidence of GI cancers after BAD diagnosis and the odds ratios (ORs) of GI cancer 8 and 15 years before BAD diagnosis/matching.

RESULTS

Cumulative incidence of GI cancer 6 years after BAD diagnosis/matching was 1.6% in the BAD group and 1.1% in controls ( P = 0.01). The ORs of total GI cancer 8 and 15 years before BAD diagnosis were 6.16 (5.08-7.48) and 5.19 (4.28-6.29), respectively. Furthermore, 47 individuals with BAD (0.9%) and 250 (0.5%) controls died of GI cancer.

DISCUSSION

This nationwide cohort study indicates an association between BAD and GI cancers. We found both a higher incidence of GI cancer after BAD diagnosis compared with controls and increased OR of GI cancer before BAD diagnosis. Bearing in mind the underdiagnosis of BAD, the delay of BAD diagnosis, and the carcinogenic effect of bile acids, these findings warrant further investigations of the risk of GI cancer in individuals with BAD.

A New Strategy for Dietary Nutrition to Improve Intestinal Homeostasis in Diarrheal Irritable Bowel Syndrome: A Perspective on Intestinal Flora and Intestinal Epithelial Interaction

BACKGROUND AND OBJECTIVES

Although a reasonable diet is essential for promoting human health, precise nutritional regulation presents a challenge for different physiological conditions. Irritable Bowel Syndrome (IBS) is characterized by recurrent abdominal pain and abnormal bowel habits, and diarrheal IBS (IBS-D) is the most common, seriously affecting patients' quality of life. Therefore, the implementation of precise nutritional interventions for IBS-D has become an urgent challenge in the fields of nutrition and food science. IBS-D intestinal homeostatic imbalance involves intestinal flora disorganization and impaired intestinal epithelial barrier function. A familiar interaction is evident between intestinal flora and intestinal epithelial cells (IECs), which together maintain intestinal homeostasis and health. Dietary patterns, such as the Mediterranean diet, have been shown to regulate gut flora, which in turn improves the body's health by influencing the immune system, the hormonal system, and other metabolic pathways.

METHODS

This review summarized the relationship between intestinal flora, IECs, and IBS-D. It analyzed the mechanism behind IBS-D intestinal homeostatic imbalance by examining the interactions between intestinal flora and IECs, and proposed a precise dietary nutrient intervention strategy.

RESULTS AND CONCLUSION

This increases the understanding of the IBS-D-targeted regulation pathways and provides guidance for designing related nutritional intervention strategies.

Assessing Diagnostic Performance of Modifications to the Rome IV Criteria for Irritable Bowel Syndrome

The gold standard symptom-based criteria for diagnosis of irritable bowel syndrome (IBS) are the Rome IV criteria.1 These are more restrictive than their predecessor, Rome III, because the cardinal feature required to meet criteria for IBS was changed to presence of abdominal pain alone, rather than abdominal pain or discomfort.2 This change was made because discomfort was believed to be an ambiguous term, with no equivalent in some languages. In addition, symptom frequency required for the presence of abdominal pain was increased to 1 day per week from 2 to 3 days per month. This has led to reduced sensitivity for detecting IBS and a 50% decrease in the prevalence of the disorder in the community.3,4 In a cross-sectional survey applying both Rome IV and III criteria to people living with IBS, 89% of those with Rome III-defined IBS not meeting Rome IV criteria did not meet Rome IV criteria because of this change in pain frequency.5 Previous iterations of the Rome criteria have performed only modestly in predicting a diagnosis of IBS.6-8 However, in a validation study, the Rome IV criteria outperformed Rome III,9 largely because their more restrictive nature made them more specific than Rome III. We assessed whether modifications to the Rome IV criteria led to a better trade-off between sensitivity and specificity.

Evidence-Based Clinical Guidelines for Chronic Diarrhea 2023

The Japan Gastroenterological Association (JGA) published the first version of clinical guidelines for chronic diarrhea 2023. These guidelines describe the definition, classification, diagnostic criteria, diagnostic testing methods, epidemiology, pathophysiology, and treatment of chronic diarrhea, and provide flowcharts for the diagnosis and treatment of chronic diarrhea based on the latest evidence. Treatment for chronic diarrhea begins by distinguishing secondary chronic constipation with a clear etiology, such as drug-induced diarrhea, food-induced diarrhea, systemic disease-associated diarrhea, infection-associated diarrhea, organic disease-associated diarrhea, and bile acid diarrhea. The first line of treatment for chronic diarrhea in the narrow sense, defined in these guidelines as functional diarrhea in routine medical care, is lifestyle modification and dietary therapy. The first medicines to be considered for oral treatment are probiotics for regulating the gut microbiome and anti-diarrheals. Other medications, such as 5HT3 receptor antagonists, anticholinergics, Kampo medicine, psychotherapy, antibiotics, bulking agents, adrenergic agonists, and somatostatin analogs, lack sufficient evidence for their use, highlighting a challenge for future research. This Clinical Guidelines for Chronic Diarrhea 2023, which provides the best clinical strategies for treating chronic diarrhea in Japan, will also be useful for medical treatment worldwide.

Prevalence and determinants of postprandial diarrhea in a tertiary care center

BACKGROUND AND AIMS

Postprandial diarrhea (PPD) is commonly seen in patients with disorders of gut-brain interaction (DGBI), but the factors associated with it have not been well studied. In this study, we aim to study the burden, impact, and predictors of PPD using a clinical cohort of DGBI patients.

METHODS

This study included patients with chronic diarrhea fulfilling ROME IV criteria for irritable bowel syndrome (IBS) or functional diarrhea (FDiarr). PPD was defined as patients reporting mushy/watery stools following meals ≥30% of the time in the last 3 months using a ROME IV question on PPD. Age, sex, and BMI, the severity of diarrhea, abdominal pain, depression, anxiety, somatization, and quality of life were assessed using validated measures. Person's chi-square test and Student's t-test were used to compare variables. A multiple linear regression model with backward elimination was done to determine predictors of PPD severity.

KEY RESULTS

Of 213 eligible patients, more than three-fourth of patients (75.6%) had PPD. Women (79.0%, p = 0.037), patients with ROME IV diagnosis of IBS-D (90.5%, p = 0.002), and functional dyspepsia (83.2%, p = 0.014), and those with a history of cholecystectomy (CCY) (95.5%, p = 0.022) were more likely to report PPD. PPD patients experienced more severe abdominal pain, diarrhea, and decreased quality of life (QoL) but showed no significant difference in BMI, anxiety, depression, sleep, or somatization. In our regression model, female sex and history of CCY were independent predictors of PPD.

CONCLUSIONS AND INFERENCES

PPD is frequently reported among chronic diarrhea patients and is associated with more severe GI symptoms and decreased QoL. Female sex and CCY predict PPD, while psychological factors do not.

Metabolic biomarkers in irritable bowel syndrome diagnosis

Irritable bowel syndrome (IBS) is a chronic gastrointestinal (GI) disorder characterized by altered bowel habits and abdominal discomfort during defecation. It significantly impacts life quality and work productivity for those affected. Global data suggests a slightly higher prevalence in females than in males. Today, unambiguous diagnosis of IBS remains challenging due to the absence of a specific biochemical, histopathological, or radiological test. Current diagnosis relies heavily on thorough symptom evaluation. Efforts by the Rome committees have established standardized diagnostic criteria (Rome I-IV), improving consistency and clinical applicability. Recent studies in this framework, seem to have successfully employed metabolomics techniques to identify distinct metabolite profiles in breath and stool samples of IBS patients, differentiating them from healthy controls and those with other functional GI disorders, such as inflammatory bowel disease (IBD). Building on this success, researchers are investigating the presence of similar metabolites in easily accessible biofluids such as urine, potentially offering a less invasive diagnostic approach. Accordingly, this review focuses on key metabolites specifically detected in IBS patients' biological specimens, with a focus on urinary metabolites, using various methods, particularly mass spectrometry (MS)-based techniques, including gas chromatography-MS (GC-MS), liquid chromatography-tandem MS (LC-MS/MS), and capillary electrophoresis-MS (CE-MS) metabolomics assays. These findings may make provision for a new set of non-invasive biomarkers for IBS diagnosis and management.

Review article: A practical approach to persistent gastrointestinal symptoms in inflammatory bowel disease in remission

BACKGROUND

Persistent gastrointestinal symptoms are prevalent in adult patients with inflammatory bowel disease (IBD), even when endoscopic remission is reached. These symptoms can have profound negative effects on the quality of life of affected patients and can be difficult to treat. They may be caused by IBD-related complications or comorbid disorders, but they can also be explained by irritable bowel syndrome (IBS)-like symptoms.

AIMS

To provide a practical step-by-step guide to diagnose and treat persistent gastrointestinal symptoms in patients with IBD in remission via a personalised approach.

METHODS

We scrutinised relevant literature on causes, diagnostics and treatment of persistent gastrointestinal symptoms (abdominal pain or discomfort, bloating, abdominal distension, diarrhoea, constipation and faecal incontinence) in patients with IBD in remission.

RESULTS

A graphical practical guide for several steps in diagnosing, identifying potential triggers and adequate treatment of persistent gastrointestinal symptoms in IBD in remission is provided based on supporting literature. The first part of this review focuses on the diagnostic and treatment approaches for potential IBD-related complications and comorbidities. The second part describes the approach to IBS-like symptoms in IBD in remission.

CONCLUSIONS

Persistent gastrointestinal symptoms in IBD in remission can be traced back to potential pathophysiological mechanisms in individual patients and can be treated adequately. For both IBD-related complications and comorbidities and IBS-like symptoms in IBD in remission, pharmacological, dietary, lifestyle or psychological treatments can be effective. A systematic and personalised approach is required to reduce the burden for patients, healthcare systems, and society.

Comparison between SeHCAT test and clinical response to cholestyramine in patients with chronic diarrhea and high suspicion of bile acid malabsorption: A single-center prospective study

OBJECTIVES

We aimed to evaluate the clinical response to cholestyramine in patients with functional chronic diarrhea and a high clinical suspicion of bile-acid diarrhea (BAD) investigated with 75-selenium homocholic acid taurine (SeHCAT) test.

METHODS

Adult patients attending our outpatient clinic between January and December 2021 for chronic diarrhea with suspicion of BAD were proposed SeHCAT testing and a therapeutic trial of cholestyramine 4-8 g daily. Clinical response to cholestyramine was evaluated at 1, 3, 6, and 12 months. Clinical and demographic data were analyzed according to SeHCAT test results.

RESULTS

Among the 50 patients with chronic diarrhea and clinical suspicion of BAD, 13 (26.0%) refused either SeHCAT testing or cholestyramine therapy. Finally, 37 patients (31 females, age 44 ± 14 years) agreed to undergo SeHCAT and were started on cholestyramine (median follow-up 14 months [interquartile range 6-16 months]). Initial response to cholestyramine was similar in patients with positive and negative SeHCAT test results, but improved over time in those with a positive test result. Long-term response (100% vs 65.2%, P = 0.02) and necessity of maintenance therapy for symptom control were more common in those with positive SeHCAT test result (71.4% vs 26.1%, P = 0.02). However, response to cholestyramine was also frequent in patients with a negative test result.

CONCLUSIONS

The SeHCAT test accurately identifies patients with BAD who benefit from long-term cholestyramine treatment. Nevertheless, cholestyramine may be also effective in patients with chronic diarrhea but negative SeHCAT test result.

Risk of cancer in patients with bile acid diarrhoea: a Danish nationwide matched cohort study

OBJECTIVE

Bile acid diarrhoea is a common cause of chronic diarrhoea. Increased levels of potentially carcinogenic bile acids in faeces, theoretically, may increase the risk of colorectal cancer in particular, but the long-term disease course is unknown. We aimed to investigate the overall and site-specific cancer risk in bile acid diarrhoea.

DESIGN

Adult patients with bile acid diarrhoea were identified using nationwide Danish registries from 2003 to 2020 by a diagnostic gold-standard 75-selenium tauroselcholic acid procedure followed within 6 months by sequestrant prescription. The risk of overall and site-specific cancers in cases with bile acid diarrhoea was compared with sex, age and comorbidity-adjusted matched controls. A competing risk model estimated cumulative incidence functions and cause-specific HRs.

RESULTS

We identified 2260 patients with bile acid diarrhoea with a mean follow-up of 5.5 years (SD 4.2). The overall cancer risk was increased by an HR of 1.32 (95% CI 1.12 to 1.54). The risk of site-specific cancer was increased in 3 of 10 cancer groups: haematological, HR 2.41 (1.36 to 4.02); skin, HR 1.33 (1.01 to 1.71); and male genital cancers, HR 1.85 (1.11 to 2.92). No increased risk of colorectal cancer was detected in patients with bile acid diarrhoea, HR 0.73 (0.34 to 1.63).

CONCLUSIONS

Bile acid diarrhoea was associated with an increased overall risk of cancer, especially haematological cancers, but the risk of colorectal cancer was not increased. The lack of a diagnostic code for bile acid diarrhoea and potential residual confounding are limitations, and the findings should be replicated in other cohorts.

[Bile Acid Diarrhea]

Diarrhea is a very common gastrointestinal symptom, and the presence of higher concentrations of bile acid in the colon leads to bile acid diarrhea (BAD). In BAD patients, a portion of bile from the small intestine that is normally controlled by enterohepatic circulation is present at a high concentration in the lumen of the large intestine, resulting in increased motility and secretion of the large intestine. The prevalence of BAD is estimated to be 1-2% of the general population, and it comprises one-third of the instances of diarrhea-predominant irritable bowel syndrome. The clinical symptoms of BAD include chronic diarrhea, increased frequency of defecation, urgency to defecate, fecal incontinence, and cramping abdominal pain. The pathophysiology of BAD has not yet been fully elucidated. However, recent studies have reported increased intestinal permeability, shortened intestinal transit time, and changes in the intestinal microbial community to be the possible causes of BAD. Although fecal and serum bile acid tests are widely used for diagnosis, new test methods that are non-invasive, inexpensive, and have high sensitivity and specificity are needed at various institutions to facilitate the diagnosis. The selenium homo-tauro-cholic acid (SeHCAT) test is the gold standard for BAD diagnosis and severity assessment. The validation of several other serum markers, such as 7-hydroxy-4-cholesten-3-one (serum 7αC4) and the fibroblast growth factor 19 (FGF19) for use in clinical practice is ongoing. Although bile acid sequestrants are the mainstay of treatment, the development of drugs that are more effective and have better compliance is required. Farnesoid X receptor (FXR) agonists are showing promising results.

Food intolerance related to gastrointestinal symptoms amongst adults living with bile acid diarrhoea: A cross-sectional study

BACKGROUND

The role of food in managing bile acid diarrhoea (BAD) is poorly understood. The present study explored the prevalence of food intolerance amongst adults with BAD.

METHODS

The study comprised a cross-sectional survey of adults with BAD determined by the 75 selenium homotaurocholic acid test (SeHCAT) living in the UK. Participants anonymously completed an online questionnaire on 39 food items. Frequency of food in general affecting BAD symptoms, as well as frequencies of diarrhoea, abdominal pain, bloating, flatulence and consequential food avoidance after food item ingestion, were assessed. Food group avoidance was also assessed.

RESULTS

There were 434 participants who completed the questionnaire between April and May 2021 of whom 80% reported moderate to severe chronic diarrhoea. Food intolerances were reported by 88.0% (95% confidence interval [CI] = 84.6-90.9) of participants. Diarrhoea was reported most frequently after take-away food, fish and chips, creamy sauces, cream and large quantities of fruit (range 41.0%-33.6%). Lowest frequencies were for potato, avocado, mango, watermelon and pear (range 3.7%-7.4%) for the foods listed in the questionnaire. Similar trends were found for abdominal pain, bloating, flatulence and consequential food avoidance. Symptom-triggering within 30 min of ingestion was more prevalence than after 30 min for almost all foods. Food group avoidance was highest for fatty foods (81.2%; 95% CI = 77.8-85.3) followed by dairy (53.9%; 95% CI = 49.1-58.7).

CONCLUSIONS

Perceived food intolerance amongst adults with BAD and persisting diarrhoeal symptoms is high. Important triggers were meals with a higher fat content and higher-fat dairy products. Diets amongst those with persisting diarrhoeal symptoms may be overly restrictive.

Bile Acid Diarrhea: From Molecular Mechanisms to Clinical Diagnosis and Treatment in the Era of Precision Medicine

Bile acid diarrhea (BAD) is a multifaceted intestinal disorder involving intricate molecular mechanisms, including farnesoid X receptor (FXR), fibroblast growth factor receptor 4 (FGFR4), and Takeda G protein-coupled receptor 5 (TGR5). Current diagnostic methods encompass bile acid sequestrants (BAS), 48-h fecal bile acid tests, serum 7α-hydroxy-4-cholesten-3-one (C4), fibroblast growth factor 19 (FGF19) testing, and 75Selenium HomotauroCholic acid test (75SeHCAT). Treatment primarily involves BAS and FXR agonists. However, due to the limited sensitivity and specificity of current diagnostic methods, as well as suboptimal treatment efficacy and the presence of side effects, there is an urgent need to establish new diagnostic and treatment methods. While prior literature has summarized various diagnostic and treatment methods and the pathogenesis of BAD, no previous work has linked the two. This review offers a molecular perspective on the clinical diagnosis and treatment of BAD, with a focus on FXR, FGFR4, and TGR5, emphasizing the potential for identifying additional molecular mechanisms as treatment targets and bridging the gap between diagnostic and treatment methods and molecular mechanisms for a novel approach to the clinical management of BAD.

Prospective comparison of diagnostic tests for bile acid diarrhoea

BACKGROUND

Bile acid diarrhoea is often missed because gold standard nuclear medicine tauroselcholic [75-Se] acid (SeHCAT) testing has limited availability. Empirical treatment effect has unknown diagnostic performance, whereas plasma 7α-hydroxy-4-cholesten-3-one (C4) is inexpensive but lacks sensitivity.

AIMS

To determine diagnostic characteristics of empirical treatment and explore improvements in diagnostics with potential better availability than SeHCAT.

METHODS

This diagnostic accuracy study was part of a randomised, placebo-controlled trial of colesevelam. Consecutive patients with chronic diarrhoea attending SeHCAT had blood and stool sampled. Key thresholds were C4 > 46 ng/mL and SeHCAT retention ≤10%. A questionnaire recorded patient-reported empirical treatment effect. We analysed receiver operating characteristics and explored machine learning applied logistic regression and decision tree modelling with internal validation.

RESULTS

Ninety-six (38%) of 251 patients had SeHCAT retention ≤10%. The effect of empirical treatment assessed with test results for bile acid studies blinded had 63% (95% confidence interval 44%-79%) sensitivity and 65% (47%-80%) specificity; C4 > 46 ng/mL had 47% (37%-57%) and 92% (87%-96%), respectively. A decision tree combining C4 ≥ 31 ng/mL with ≥1.1 daily watery stools (Bristol type 6 and 7) had 70% (51%-85%) sensitivity and 95% (83%-99%) specificity. The logistic regression model, including C4, the sum of measured stool bile acids and daily watery stools, had 77% (58%-90%) sensitivity and 93% (80%-98%) specificity.

CONCLUSIONS

Diagnosis of bile acid diarrhoea using empirical treatment was inadequate. Exploration suggested considerable improvements in the sensitivity of C4-based testing, offering potential widely available diagnostics. Further validation is warranted.

CLINICALTRIALS

gov: NCT03876717.

The Epidemiology of Bile Acid Diarrhea in Denmark

Objective

Bile acid diarrhea (BAD) is a socially debilitating disease with frequent bowel movements, urgency, and fecal incontinence as the main symptoms. It is caused by excessive bile acid levels in the colon and is most commonly treated with bile acid sequestrants. It is estimated that 1-2% of the population suffers from the disease, but only a fraction of these are properly diagnosed with the gold standard ⁷⁵selenium-homotaurocholic acid (SeHCAT) test. Here, we use nationwide registries to describe the demographic characteristics of individuals suffering from BAD in Denmark.

Methods

Since the International Classification of Diseases diagnosis code for BAD was not used until 2021, we identified the BAD population by referral to SeHCAT testing followed by a prescription of a bile acid sequestrant (colestyramine, colestipol or colesevelam) within 365 days. The study period was from 2003 to 2021.

Results

During the study period, a total of 5264 individuals with BAD were identified with large differences between the five regions in Denmark. The number of prescriptions of colestyramine and colesevelam, the number of SeHCAT tests, and the number of individuals diagnosed with BAD increased during the study period. The BAD population had more co-morbidities and more health care contacts as well as lower levels of education and income compared with age- and sex-matched controls from the general population.

Conclusion

Using the Danish registries, we identified a BAD population, which seems to be inferior in health care and socio-economic parameters compared with the Danish general population.

Recent developments in diagnosing bile acid diarrhea

INTRODUCTION

Bile acid diarrhea (BAD) commonly causes chronic diarrhea. Symptoms may be mistaken for disorders of gut brain interaction. Due to the lack of widely available diagnostic tests and poor recognition of BAD, there is a delay in diagnosis leading to increased healthcare system burden and decreased patient quality of life.

AREAS COVERED

A thorough review of the literature was conducted using PubMed for articles on the biological functions of bile acids, pathophysiology and management of BAD, but focusing on diagnostic testing including 75SeHCAT retention, 7αC4, FGF-19, fecal bile acids, and single stool tests. This narrative review discusses available modalities focusing on noninvasive stool and serum testing that are more widely available and show good sensitivity and specificity for diagnosis of BAD. 75SeHCAT retention is not available in many countries. Alternative diagnostic tests include total and primary fecal bile acid (BA) excretion in 48-hour collection or a single stool sample, serum7αC4 >46 or 52.5 ng/mL, and combination of single stool and serum 7αC4 ±watery stools (Bristol Stool Form Scale 6-7).

EXPERT OPINION

Given the ease of serum and single stool sample acquisition and diagnostic advances, clinical practice should embrace positive diagnosis, rather than BAS therapeutic trial. BAD needs to be considered in diverse gastrointestinal diseases.

Diagnosis and treatment of post-cholecystectomy diarrhoea

The incidence of cholecystitis is relatively high in developed countries and may usually be attributed to gallstones, the treatment for which involves complete surgical removal of the gallbladder (cholecystectomy). Bile acids produced following cholecystectomy continue to flow into the duodenum but are poorly absorbed by the colon. Excessive bile acids in the colon stimulate mucosal secretion of water and electrolytes leading, in severe cases, to diarrhoea. Bile acid diarrhoea (BAD) is difficult to diagnose, requiring a comprehensive medical history and physical examination in combination with laboratory evaluation. The current work reviews the diagnosis and treatment of BAD following cholecystectomy.

Serum lipidome unravels a diagnostic potential in bile acid diarrhoea

OBJECTIVE

Bile acid diarrhoea (BAD) is debilitating yet treatable, but it remains underdiagnosed due to challenging diagnostics. We developed a blood test-based method to guide BAD diagnosis.

DESIGN

We included serum from 50 treatment-naive patients with BAD diagnosed by gold standard 75selenium homotaurocholic acid test, 56 feature-matched controls and 37 patients with non-alcoholic fatty liver disease (NAFLD). Metabolomes were generated using mass spectrometry covering 1295 metabolites and compared between groups. Machine learning was used to develop a BAD Diagnostic Score (BDS).

RESULTS

Metabolomes of patients with BAD significantly differed from controls and NAFLD. We detected 70 metabolites with a discriminatory performance in the discovery set with an area under receiver-operating curve metric above 0.80. Logistic regression modelling using concentrations of decanoylcarnitine, cholesterol ester (22:5), eicosatrienoic acid, L-alpha-lysophosphatidylinositol (18:0) and phosphatidylethanolamine (O-16:0/18:1) distinguished BAD from controls with a sensitivity of 0.78 (95% CI 0.64 to 0.89) and a specificity of 0.93 (95% CI 0.83 to 0.98). The model was independent of covariates (age, sex, body mass index) and distinguished BAD from NAFLD irrespective of fibrosis stage. BDS outperformed other blood test-based tests (7-alpha-hydroxy-4-cholesten-3-one and fibroblast growth factor 19) currently under development.

CONCLUSIONS

BDS derived from serum metabolites in a single-blood sample showed robust identification of patients with BAD with superior specificity and sensitivity compared with current blood test-based diagnostics.

Emerging uses of glucagon-like peptide 1 (GLP-1) receptor agonists following ileal resection: literature review and case examples

Following ileal resection, the combination of severe bile acid (BA) malabsorption, rapid small bowel transit and unrestricted upper gastrointestinal (GI) secretion results in severe diarrhoea that can prove refractory to pharmacological therapies. While established therapies, including BA sequestrants and antidiarrhoeal drugs seek to ameliorate symptoms, they do not target the underlying pathophysiological mechanisms in this patient group. Their use can also be limited by both intolerance and adverse effects. The novel use of glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) in these patients may allow restoration of the physiological negative feedback mechanisms lost in ileal resection and reduce diarrhoea by prolonging small bowel transit time, limiting upper GI secretions and perhaps by inhibiting hepatic BA synthesis. While recent evidence supports the use of GLP-1 RAs as a safe and effective therapy for bile acid diarrhoea (BAD), it remains uncertain whether those with severe BAD and subsequent short bowel syndrome secondary to extensive ileal resection will benefit. Here, we present three cases of severe diarrhoea secondary to extensive ileal resection in which the use of the GLP-1 RA, liraglutide, was well tolerated and resulted in an objective improvement in diarrhoeal symptoms. We further provide a narrative review of the emerging evidence base supporting the use of GLP therapies in this challenging condition.

Foundational Nutrition: Implications for Human Health

Human nutrition, and what can be considered "ideal" nutrition, is a complex, multi-faceted topic which many researchers and practitioners deliberate. While some attest that basic human nutrition is relatively understood, it is undeniable that a global nutritional problem persists. Many countries struggle with malnutrition or caloric deficits, while others encounter difficulties with caloric overconsumption and micronutrient deficiencies. A multitude of factors contribute to this global problem. Limitations to the current scope of the recommended daily allowances (RDAs) and dietary reference intakes (DRIs), changes in soil quality, and reductions in nutrient density are just a few of these factors. In this article, we propose a new, working approach towards human nutrition designated "Foundational Nutrition". This nutritional lens combines a whole food approach in conjunction with micronutrients and other nutrients critical for optimal human health with special consideration given to the human gut microbiome and overall gut health. Together, this a synergistic approach which addresses vital components in nutrition that enhances the bioavailability of nutrients and to potentiate a bioactive effect.

Bile acid diarrhea - as bad as it gets?

PURPOSE OF REVIEW

Bile acid diarrhea (BAD) is a common but under-recognized gastrointestinal condition that manifests with increased stool frequency and urgency, and a looser stool consistency. The aim of this review is to present recent advances in the pathophysiology, mechanisms, manifestations, diagnosis, and treatment of BAD.

RECENT FINDINGS

Patients with BAD have evidence of accelerated colonic transit, increased gut mucosal permeability, altered stool microbiome composition, and decreased quality of life. Single, random stool measurements of bile acids, alone or in combination with fasting serum 7-alpha-hydroxy-4-cholesten-3-one, have shown good sensitivity and specificity for the diagnosis of BAD. Novel therapeutic approaches include farnesoid X receptor agonists and glucagon-like peptide 1 agonists.

SUMMARY

Recent research has led to a better understanding of the pathophysiology and mechanisms of BAD, which might pave the way towards more targeted treatment strategies for BAD. Newer, more affordable, and easier diagnostic methods facilitate the diagnosis of BAD.

Efficacy and safety of colesevelam for the treatment of bile acid diarrhoea: a double-blind, randomised, placebo-controlled, phase 4 clinical trial

BACKGROUND

Bile acid diarrhoea is a common but overlooked cause of chronic watery diarrhoea. Plasma 7α-hydroxy-4-cholesten-3-one (C4) is an alternative to the gold standard tauroselcholic [⁷⁵Se] acid (SeHCAT) test. Low-certainty evidence supports sequestrant treatment, including colesevelam. We aimed to determine the efficacy and safety of colesevelam in bile acid diarrhoea.

METHODS

In this randomised, double-blind, placebo-controlled, investigator-initiated phase 4 trial of the sequestrant colesevelam in bile acid diarrhoea (SINBAD), we enrolled consecutive patients aged 18-79 years without inflammatory bowel disease attending SeHCAT testing for suspected bile acid diarrhoea at four Danish secondary care centres. Participants were randomly allocated 1:1 to receive 12 days of treatment with colesevelam (overencapsulated tablets of 625 mg) or placebo, with the starting dose of two capsules twice daily and titrated to effect during the first 5 days of treatment. A pharmacist independent of the clinical investigators generated a randomisation list on the web page randomization.com using block randomisation (randomisation was not stratified). C4 and SeHCAT diagnostic results were blinded during treatment. We treated all patients with diarrhoea, with a daily mean of 3·0 or more bowel movements or 1·0 or more watery bowel movements (Bristol stool scale type 6 and 7). Remission was defined as the absence of both these criteria during treatment days 6-12. The primary outcome was the intention-to-treat remission rate in bile acid diarrhoea diagnosed by C4 concentration greater than 46 ng/mL. A secondary outcome was the intention-to-treat remission rate in bile acid diarrhoea diagnosed by SeHCAT retention of 10% or less. This trial is registered with ClinicalTrials.gov, NCT03876717.

FINDINGS

Between Oct 25, 2018, and July 1, 2021, 168 patients were randomly assigned to receive colesevelam (n=84) or placebo (n=84). 41 patients had C4 concentration greater than 46 ng/mL (22 assigned to the colesevelam group and 19 to the placebo group). For the C4-defined primary outcome, 14 (64%) of 22 participants receiving colesevelam versus three (16%) of 19 participants receiving placebo achieved remission (adjusted odds ratio 9·1, 95% CI 1·9-62·8; p=0·011). For the SeHCAT-defined secondary outcome, 75 of the 168 participants had retention of less than 10% (37 assigned to the colesevelam group and 38 assigned to the placebo group); 22 (59%) of 37 participants receiving colesevelam achieved remission versus five (13%) of 38 participants receiving placebo (adjusted odds ratio 11·1, 95% CI 3·4-45·6; p=0·00020). There were no serious adverse events. Common adverse events were transient. For patients receiving colesevelam within the primary outcome population, five had abdominal pain, nine had bloating, and four had nausea. For patients receiving placebo, four had abdominal pain, four had bloating, and one had nausea. No participants with bile acid diarrhoea withdrew due to adverse events.

INTERPRETATION

Colesevelam was superior to placebo at inducing remission of bile acid diarrhoea diagnosed with C4 concentration greater than 46 ng/mL. Secondary outcome data suggest similar efficacy treating SeHCAT-defined bile acid diarrhoea. Colesevelam was safe during the treatment.

FUNDING

Fabrikant Vilhelm Pedersen og hustrus mindelegat; recommended by the Novo Nordisk Foundation.

[Frequent Gastro-Intestinal Disorders: Management of Functional Dyspepsia and Irritable Bowel Syndrome in Clinical Practice]

Frequent Gastro-Intestinal Disorders: Management of Functional Dyspepsia and Irritable Bowel Syndrome in Clinical Practice Abstract: Functional dyspepsia (FD) and irritable bowel syndrome (IBS), two common gastrointestinal entities with overlapping symptoms, should be diagnosed according to Rome IV criteria. This includes one or more of the following symptoms: in FD, postprandial fullness, early satiation, epigastric pain or burning; in IBS, recurrent abdominal pain associated with defecation, change in frequency of stool or form of stool. To exclude structural diseases, attention should be paid to alarm symptoms. As far as treatment is concerned, a stepwise scheme proves to be effective for both diseases. Step 1: doctor-patient discussion with explanation of diagnosis and prognosis as well as clarification of therapy goals; lifestyle adaptations; use of phytotherapeutics; step 2: symptom-oriented medication: for FD, PPIs or prokinetics; for IBS, antispasmodics, secretagogues, laxatives, bile acid sequestrants, antidiarrheals, antibiotics, probiotics; step 3: visceral analgesics (antidepressants).

Biomarkers for Bile Acid Malabsorption in Diarrhea-predominant Irritable Bowel Syndrome: A Systematic Review and Meta-analysis

BACKGROUND AND AIM

A clear relationship of biological indexes between bile acid malabsorption (BAM) and diarrhea-predominant irritable bowel syndrome (IBS-D) has not been well analyzed. This meta-analysis aimed to establish a more convenient method to diagnose BAM in IBS-D patients by comparing the differences in biomarkers between IBS-D patients and healthy people.

METHODS

Multiple databases were searched for relevant case-control studies. Indicators used to diagnose BAM included 75Se-homocholic acid taurine (SeHCAT), 7α-hydroxy-4-cholesten-3-one(C4), fibroblast growth factor-19 and 48-hour fecal bile acid (48FBA). The rate of BAM (SeHCAT) was calculated by using a random-effect model. The levels of C4, FGF19, and 48FBA were compared, and the overall effect size was combined by a fixed effect model.

RESULTS

The search strategy identified 10 relevant studies comprising 1034 IBS-D patients and 232 healthy volunteers. The pooled rate of BAM in IBS-D patients was 32% (according to SeHCAT; 95% CI: 24%-40%). The level of C4 in IBS-D patients was significantly higher than that in the control group (2.86 ng/mL; 95% CI: 1.09, 4.63); The level of FGF19 was significantly lower than that in the control group (-33.97 pg/mL; 95% CI: -51.13, -16.82); The level of 48FBA was significantly higher than that in the control group (0.059; 95% CI: 0.41, 0.77).

CONCLUSIONS

The results mainly concluded serum C4 and FGF19 levels in IBS-D patients. Most of the studies have different normal cutoff points of serum C4 and FGF19 levels; the performance of each test should be further estimated. By comparing the levels of these biomarkers, BAM in patients with IBS-D could be identified more accurately, which would lead to more effective treatment.

Postoperative diarrhea in Crohn's disease: Pathogenesis, diagnosis, and therapy

Diarrhea is a frequent symptom in postoperative patients with Crohn's diseases (CD), and several different mechanisms likely account for postoperative diarrhea in CD. A targeted strategy based on a comprehensive understanding of postoperative diarrhea is helpful for better postoperative recovery.

Associations of Fecal Short Chain Fatty Acids With Colonic Transit, Fecal Bile Acid, and Food Intake in Irritable Bowel Syndrome

INTRODUCTION

Short-chain fatty acids (SCFAs) correlate with colonic transit time (CTT) and may influence irritable bowel syndrome (IBS) pathophysiology. However, the clinical significance of fecal SCFAs, relationships between SCFAs and other metabolites (bile acids [BAs]), and real-time diet effects on SCFAs in IBS are uncertain. The aim was to evaluate fecal SCFA associations with IBS phenotype and mechanisms and explore effects of real-time diet.

METHODS

We conducted a prospective observational study of fecal SCFA, BAs, and CTT in healthy controls (HCs) and participants with IBS. We compared study end points across groups, analyzed relationships between end points, and evaluated the discriminative ability of SCFAs. Diet effects were explored in participants with dietary data.

RESULTS

Among 21 HCs and 43 participants with IBS, fecal SCFAs (total, individual) were inversely correlated with overall (all P < 0.01) and segmental (all P < 0.05) CTT; similar associations were observed within HC and IBS groups. The acetate-to-butyrate ratio correlated with slower overall and left CTT in all and in HCs (both P < 0.01). SCFAs (total, acetate) correlated with BAs (total, % primary) in all participants and in those with IBS with diarrhea. Logistic regression analyses demonstrated associations of acetate with slower transit (odds ratio = 0.988, P = 0.002) and BA diarrhea (BAD; odds ratio = 1.014, P = 0.001). Acetate accurately predicted delayed CTT (area under the receiving operating characteristic curve = 0.84) and BAD (area under the receiver operating characteristic curve = 0.79). Adjusting for diet strengthened correlations of total SCFAs with overall CTT ( R = [-0.46], P = 0.04) and SCFAs with transverse CTT (all P < 0.05).

DISCUSSION

Fecal SCFAs correlate with CTT and fecal BAs and reliably exclude delayed CTT and BAD. Accounting for diet strengthens SCFA associations with transit.

Chologene Diarrhö, Stiefkind der chronischen Diarrhö – Prävalenz, Diagnostik und Therapie

Die chologene Diarrhö ist eine der häufigsten nicht diagnostizierten Ursachen der chronischen Diarrhö, der zahlreiche verschiedene Pathophysiologien zugrunde liegen können. Auch nach Ausschlussdiagnostik der häufigeren Ursachen verbleiben bis zu 5% der Bevölkerung von einer ungeklärten chronischen Diarrhö betroffen. In diesem Kollektiv findet sich in bis zu 50% als Ursache eine chologene Diarrhö.

Effectiveness of diet, psychological, and exercise therapies for the management of bile acid diarrhoea in adults: A systematic review

BACKGROUND

Bile acid diarrhoea (BAD) causes chronic diarrhoea and is primarily treated pharmacologically. This systematic review aimed to evaluate the effectiveness of non-pharmacological therapies for evidence-based management of BAD in adults.

METHODS

A systematic review of the medical literature was performed from 1975 to 13 July 2021 to identify studies on diet, psychological, and exercise therapies that met diagnostic criteria for BAD in adults with diarrhoea. Effectiveness was judged by responder or improvement in diarrhoea at study endpoint according to each study's definition of diarrhoea. Therapeutic effect on abdominal pain and flatulence was also measured. Risk of bias was assessed using the Risk Of Bias In Non-Randomised Studies of Interventions tool. A narrative review was conducted using 'Synthesis Without Meta-analysis' guidance. Certainty of the evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation.

RESULTS

Eight prospective cohort studies were identified on diet therapies from 2 weeks to over 2 years involving 192 patients. No psychological or exercise therapies were found. Carbohydrate modification (one study, n = 2) in primary BAD, and dietary fat intake reductions (five studies, n = 181) and an exclusive elemental diet therapy (two studies, n = 9) in secondary BAD, showed beneficial directions of effect on diarrhoea, abdominal pain, and flatulence. Risks of bias for each study and across studies for each therapy type were serious. Certainty of the evidence was very low for all outcomes.

CONCLUSIONS

No conclusions could be drawn on the effectiveness of diet, psychological, or exercise therapies on diarrhoea, abdominal pain, and flatulence for the management of BAD in adults. High-quality randomised controlled trials are needed.

Chronic loose stools following right-sided hemicolectomy for colon cancer and the association with bile acid malabsorption and small intestinal bacterial overgrowth

AIM

Patients treated with right-sided hemicolectomy for colon cancer may suffer from long-term bowel dysfunction, including loose stools, urgency and faecal incontinence. The underlying causes are poorly understood. The aim of this case-control study was to investigate the aetiology of chronic loose stools among patients with right-sided hemicolectomy curatively operated for cancer.

METHOD

Cases with chronic loose stools (Bristol stool type 6-7) after right-sided hemicolectomy were compared with a control group of patients with right-sided hemicolectomy without loose stools. All patients underwent a selenium-75 homocholic acid taurine (SeHCAT) scan to diagnose bile acid malabsorption (BAM) and a glucose breath test to diagnose small intestinal bacterial overgrowth (SIBO). Gastrointestinal transit time (GITT) was assessed with radiopaque markers. In a subgroup of patients, fibroblast growth factor 19 (FGF19) was measured in fasting blood. SIBO was treated with antibiotics and BAM was treated with bile acid sequestrants.

RESULTS

We included 45 cases and 19 controls. In the case group, 82% (n = 36) had BAM compared with 37% (n = 7) in the control group, p < 0.001. SIBO was diagnosed in 73% (n = 33) of cases with chronic loose stools and in 74% (n = 14) of controls, p = 0.977. No association between BAM and SIBO was observed. GITT was similar in cases and controls. No difference in median FGF19 was observed between cases and controls (p = 0.894), and no correlation was seen between FGF19 and SeHCAT retention (r_s 0.20, p = 0.294). Bowel symptoms among cases were reduced after treatment.

CONCLUSION

BAM and SIBO are common in patients having undergone right-sided hemicolectomy for cancer. Chronic loose stools were associated with BAM but not with SIBO.

SeHCAT (tauroselcholic [75selenium] acid) for the investigation of bile acid diarrhoea in adults: a systematic review and cost-effectiveness analysis

Background

Tauroselcholic [75selenium] acid (SeHCAT™) (GE Healthcare, Chicago, IL, USA) is a radiopharmaceutical that may be useful in diagnosing bile acid diarrhoea.

Objectives

To assess the clinical effectiveness and cost-effectiveness of SeHCAT for the investigation of adults with chronic unexplained diarrhoea, diarrhoea-predominant irritable bowel syndrome or functional diarrhoea (suspected primary bile acid diarrhoea), and adults with chronic diarrhoea and Crohn’s disease who have not undergone ileal resection (suspected secondary bile acid diarrhoea).

Methods

Sixteen databases were searched to November 2020. The review process included measures to minimise error and bias. Results were summarised by primary or secondary bile acid diarrhoea and study quality was considered. The cost-effectiveness analysis combined a short-term (6-month) decision-analytic model (diagnosis and initial treatment response) and a lifetime Markov model comprising three health states (diarrhoea, no diarrhoea and death), with transitions determined by probabilities of response to treatment. Analyses were conducted from an NHS and Personal Social Services perspective.

Results

Twenty-four studies were included in this review. Of these, 21 were observational studies, reporting some outcome data for patients treated with bile acid sequestrants, and in which only patients with a positive SeHCAT test were offered bile acid sequestrants. The median rate of response to bile acid sequestrants, among patients with a 7-day SeHCAT retention value of ≤ 15%, was 68% (range 38–86%) (eight studies). The estimated sensitivity of SeHCAT (≤ 15% threshold) to predict positive response to colestyramine was 100% (95% confidence interval 54.1% to 100%) and the specificity estimate was 91.2% (95% confidence interval 76.3% to 98.1%) (one study). The median proportion of treated patients who were intolerant/discontinued bile acid sequestrants was 15% (range 4–27%) (eight studies). There was insufficient information to determine whether or not intolerance varied between colestyramine, colestipol and colesevelam. For both populations, the SeHCAT 15% (i.e. a SeHCAT retention value of ≤ 15%) strategy dominated other strategies or resulted in incremental cost-effectiveness ratios of < £20,000–30,000 per quality-adjusted life-year gained. For the suspected primary bile acid diarrhoea population, SeHCAT 15% was the strategy most likely to be cost-effective: 67% and 73% probability at threshold incremental cost-effectiveness ratios of £20,000 and £30,000 per quality-adjusted life-year gained, respectively. For the Crohn’s disease population, these probabilities were 89% and 92% at £20,000 and £30,000 per quality-adjusted life-year gained, respectively. Cost-effectiveness was mostly led by treatment response. SeHCAT 15% was the strategy with the highest response rate in the majority of scenarios explored.

Limitations and conclusions

There is a lack of evidence linking the use of SeHCAT testing to patient-relevant outcomes. The optimal SeHCAT threshold, to define bile acid diarrhoea and select patients for treatment with bile acid sequestrants, is uncertain. It is unclear whether or not patients with ‘borderline’ or ‘equivocal’ 7-day SeHCAT retention values (e.g. between 10% and 15%) and patients with values of > 15% could benefit from treatment with bile acid sequestrants. Although the results of the economic evaluation conducted for both populations indicated that the SeHCAT 15% strategy dominated the other two strategies or resulted in incremental cost-effectiveness ratios that were lower than the common thresholds of £20,000 or £30,000 per quality-adjusted life-year gained, the paucity and poor quality of evidence mean that uncertainty is high.

Future work

The optimum study design would be a multiarm randomised controlled trial, in which participants meeting the inclusion criteria are randomised to receive colestyramine, colestipol, colesevelam or placebo, and all participants receive SeHCAT testing.

Study registration

This study is registered as PROSPERO CRD42020223877.

Funding

This project was funded by the National Institute for Health and Care Research (IHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 26, No. 45. See the NIHR Journals Library website for further project information.

Bile Acid and Gut Microbiota in Irritable Bowel Syndrome

Gut microbiota and their metabolites like bile acid (BA) have been investigated as causes of irritable bowel syndrome (IBS) symptoms. Primary BAs are synthesized and conjugated in the liver and released into the duodenum. BA biotransformation by gut microbiota begins in the intestine and results in production of a broad range of secondary BAs. Deconjugation is considered the gateway reaction for further modification and is mediated by bile salt hydrolase, which is widely expressed by the gut microbiota. However, gut bacteria that convert primary BAs to secondary BAs belong to a limited number of species, mainly Clostridiales. Like gut microbiota modify BA profile, BAs can shape gut microbiota via direct and indirect actions. BAs have prosecretory effects and regulates gut motility. BAs can also affect gut sensitivity. Because of the vital role of the gut microbiota and BAs in gut function, their bidirectional relationship may contribute to the pathophysiology of IBS. Individuals with IBS have been reported to have altered microbial profiles and modified BA profiles. A significant increase in fecal primary BA and a corresponding decrease in secondary BA have been observed in IBS with predominant diarrhea. In addition, primary BA was positively correlated with IBS symptoms. In IBS with predominant diarrhea, bacteria with reduced abundance mainly belonged to the genera in Ruminococcaceae and exhibited a negative correlation with primary BAs. Integrating the analysis of the gut microbiota and BAs could better understanding of IBS pathophysiology. The gap in this field needs to be further filled in the future.

Impact of Bile Acid Diarrhea in Patients With Diarrhea-Predominant Irritable Bowel Syndrome on Symptoms and Quality of Life

BACKGROUND & AIMS

Bile acid diarrhea (BAD) affects approximately a quarter of patients with irritable bowel syndrome with diarrhea (IBS-D). We aimed to compare the demographics, bowel and somatic symptoms, and quality of life of patients with IBS-D, with or without BAD.

METHODS

On one occasion, patients with IBS-D (positive for Rome III criteria) completed the following questionnaires: bowel disease questionnaire, Hospital Anxiety and Depression inventory, general quality of life (Symptom Checklist-90), and IBS-specific quality of life. A fasting serum C4 level higher than 52.5 ng/mL was used as a biomarker for BAD. Statistical analysis included a multiple variable logistic model to identify strong predictors of BAD in IBS-D.

RESULTS

Among 219 patients (79% female) with IBS-D, 44 had BAD; the BAD group was significantly older and had a higher body mass index than the patients without BAD. Patients with BAD had more severe bowel dysfunction and impact on IBS-specific quality of life (need of toilet proximity) compared with patients with IBS-D without BAD. Patients with BAD were more likely than other IBS-D groups to receive antidiarrheals, bile acid binders, and antacid secretory agents. The severity of diarrhea and need of toilet proximity were predictors of BAD in IBS-D (P < .01). Patients with BAD were more likely to have a depression score higher than 8 on the Hospital Anxiety and Depression inventory.

CONCLUSIONS

There is a greater impact on bowel and somatic symptoms and quality of life in IBS-D with BAD compared with IBS-D without BAD. Screening for BAD in IBS-D is especially relevant, with more severe and frequent diarrhea along with urgency.

Modulating the gut microenvironment as a treatment strategy for irritable bowel syndrome: a narrative review

Irritable bowel syndrome (IBS) is a disorder of gut-brain interaction with a complex pathophysiology. Growing evidence suggests that alterations of the gut microenvironment, including microbiota composition and function, may be involved in symptom generation. Therefore, attempts to modulate the gut microenvironment have provided promising results as an indirect approach for IBS management. Antibiotics, probiotics, prebiotics, food and faecal microbiota transplantation are the main strategies for alleviating IBS symptom severity by modulating gut microbiota composition and function (eg. metabolism), gut barrier integrity and immune activity, although with varying efficacy. In this narrative review, we aim to provide an overview of the current approaches targeting the gut microenvironment in order to indirectly manage IBS symptoms.

Usefulness of colestimide for diarrhea in postoperative Crohn's disease

Background and Aim

Crohn's disease (CD) often causes intractable diarrhea after intestinal resection. Anion exchange resins have been reported to be effective in patients with bile acid diarrhea after distal ileectomy; furthermore, bile acid metabolism has been implicated in the pathogenesis of CD. Therefore, we aimed to examine the effectiveness of colestimide in the management of postoperative CD, and to compare its impact between patients with and those without ileocecal resection.

Methods

Postoperative CD patients prescribed colestimide for diarrhea between April 2017 and December 2020 were retrospectively evaluated for changes in the total Crohn's disease activity index (CDAI), each CDAI component including diarrhea frequency/week, albumin, and C‐reactive protein (CRP) was evaluated before and after the administration of colestimide. Furthermore, comprehensive patient and physician assessments were reviewed from medical records during the first outpatient visit as a global clinical judgment after the initiation of colestimide therapy.

Results

A total of 24 patients were included, of whom 17 had a previous history of ileocecal resection. Significant improvement was noted in CDAI and diarrhea frequency only in the ileocecal resection group (CDAI: 114.5 ± 52.7 and 95.4 ± 34.8, P < 0.05; diarrhea frequency/week 23.8 ± 14.1 and 15.4 ± 11.2, P < 0.05, respectively). There was no significant improvement in other CDAI components, albumin level, or CRP level in either group. In the global clinical judgment, 13 and 4 patients in the ileocecal and non‐ileocecal resection groups, respectively, were judged as “effective,” with an overall efficacy rate of 70.8%.

Conclusion

Colestimide is effective for diarrhea in patients with postoperative CD, especially after ileocecal resection.

Safety and Efficacy of Eluxadoline in Patients with Irritable Bowel Syndrome-Diarrhea With or Without Bile Acid Diarrhea: Open-Label Study

BACKGROUND

Eluxadoline, a peripherally acting, mixed µ- and κ-opioid receptor (OR) agonist and δ-OR antagonist, is approved for treatment of adults with irritable bowel syndrome-diarrhea (IBS-D). About a third of IBS-D patients has bile acid diarrhea (BAD); opioids may stimulate TGR5 (bile acid) receptors.

AIM

To evaluate eluxadoline's efficacy on altered bowel functions and safety in IBS-D patients with or without BAD.

METHODS

In a single-center, phase 4, parallel-group, open-label study, patients with IBS-D (cohort 1) and patients with BAD were treated with eluxadoline, 100 mg tablets BID, with food for 4 weeks. Patients recorded bowel functions by electronic daily diary. BAD was based on fasting serum 7αC4 (> 52.5 ng/mL) or concurrent criteria of increased total or primary fecal BAs excreted in 48 h. We assessed efficacy on treatment compared to baseline in the two cohorts. Primary outcome measures were changes from baseline in average stool consistency Bristol Stool Form Scale (BSFS) score (range 1-7) and safety.

RESULTS

Mean changes from baseline in cohorts 1 and 2 (data presented in this order) were similar for: BSFS score averaged over 4 weeks' treatment (- 1.25 and - 1.09); daily bowel movement frequency (- 1.48 and - 0.79); daily urgent bowel movements (- 0.52 and - 0.80); IBS-QoL (5.9 and 13.6); serum 7αC4 (- 5.59 and - 8.78 ng/mL). There were no deaths, serious treatment-emergent adverse events, or discontinuations due to adverse events during the study.

CONCLUSION

Eluxadoline is similarly efficacious in the treatment of IBS-D and BAD, and it appears to be safe and efficacious as documented in large clinical trials.

The impact of treatment with bile acid sequestrants on quality of life in patients with bile acid diarrhoea

BACKGROUND

Bile acid diarrhoea (BAD) can be severely debilitating and negatively affect patients' quality of life (QoL). We carried out a multi-centre prospective study exploring QoL outcomes in patients with BAD after treatment with colesevelam.

METHODS

Patients with or without a positive 23-seleno-25-homotaurocholic acid (SeHCAT) scan were recruited and categorised into four groups: SeHCAT negative control group (CG), idiopathic BAD, post-cholecystectomy (PC) and post-terminal ileal resection for Crohn's disease (CD). Patients with a positive SeHCAT were treated with colesevelam and dosing was titrated to symptomatic response. Patients were reviewed at 4- and 8-weekly intervals and QoL was evaluated by EQ-5D-3L, SF-36, IBDQ-32 at each visit (where relevant). Patients with a negative SeHCAT (CG cohort) completed one set of questionnaires before being discharged from the study.

RESULTS

47 patients (BAD = 24, PC = 12, CD = 11) completed paired QoL questionnaires before and after treatment and 30 CG patients completed a baseline questionnaire. There was a significant improvement in IBDQ-32 mean scores before and after treatment in CD patients [134.6 (95%CI 112.5-156.6) and 158.4 (136.1-180.6), respectively (p = 0.007). Following treatment, BAD patients had significantly improved mean SF-36 scores in the "Role limitation due to physical health" dimension (p = 0.02) and in the overall mental component summary (p = 0.03). Prior to starting treatment, BAD patients had the lowest scores in the 'activity' dimension of the EQ-5D-3L (p = 0.04), which improved significantly after treatment (p = 0.002). Overall, the BAD and CD cohort showed improved mean scores with treatment in all components of the SF-36 and EQ-5D-3L, while the PC cohort showed a general decline in mean scores after treatment. 55% of patients clinically responded to treatment of which 41.7%, 58.3% and 81.8% responded from the BAD, PC and CD groups respectively. Correlations between those deemed as responders with improvements on the SF-36 and EQ-5D dimensions were not statistically significant.

CONCLUSION

Our results demonstrate improved QoL in the BAD and CD cohort with treatment. Further larger studies are recommended specifically investigating the PC cohort and whether patients may improve with newer treatments such as FXR agonists. Trial registration Ethical approval REC Ref: 16/LO/1325.

Advances in the Comprehensive Management of Postoperative Crohn's Disease

Patients with postoperative Crohn's disease are difficult to manage because of their risk of experiencing a more severe course, multiple symptom confounders, and poor sensitivity of symptomatic remission to rule out intestinal inflammation. In this group, data are lacking on biologic therapeutic efficacy, and recommendations are lacking for those with multiple medication failures. Novel noninvasive testing can simultaneously exclude alternate causes of symptoms (serum C4, fecal fat, small intestinal bowel overgrowth breath testing) and assess intestinal inflammation (fecal calprotectin, endoscopic healing index). In addition, endoscopy-based disease activity assessment and management are required. Endoscopy should be performed within 6 months of surgery, and aggressive disease activity monitoring can be considered with colonoscopy every 1-2 years subsequently to ensure late recurrence is detected. Patients with multiple resections should be screened for short bowel syndrome. Predictive biomarkers are needed to guide medication selection in this high-risk population. Postoperative prophylactic biologic therapy is prudent for patients with preoperative biologic failure. However, there are no high-quality data to guide which agent should be selected. Selecting biologics with an alternative mechanism of action in those who had failed a biologic with adequate drug concentrations and selection of different agents in those with previous intolerance are reasonable. Significantly more study is required to assess the efficacy of therapies in this setting.

Increased Fecal Bile Acid Excretion in a Significant Subset of Patients with Other Inflammatory Diarrheal Diseases

BACKGROUND

Increased fecal bile acid excretion (IBAX) occurs in a third of patients with functional diarrhea.

AIMS

To assess the prevalence of IBAX in benign inflammatory intestinal and colonic diseases presenting with chronic diarrhea.

METHODS

All patients with known inflammatory diseases or resections who underwent 48 h fecal fat and BA testing for chronic diarrhea at a single center were included. Quiescent disease was based on clinical evaluation and serum, endoscopic and imaging studies. IBAX was defined by: > 2337 µmol total BA/48 h; or primary fecal BAs > 10%; or > 4% primary BA plus > 1000 µmol total BA /48 h. Demographics, fecal weight, fecal fat, stool frequency and consistency were collected. Nonparametric statistical analyses were used for group comparisons.

RESULTS

Sixty patients had celiac disease (51 quiescent, 9 active), 66 microscopic colitis (MC: 34 collagenous, 32 lymphocytic), 18 ulcerative colitis (UC), and 47 Crohn's disease (CD). Overall, fecal fat, 48 h stool weight, frequency and consistency were not different among subgroups except for inflammatory bowel disease (IBD) based on disease location. Almost 50% patients with celiac disease and MC had IBAX, with a greater proportion with increased primary fecal BA. Among UC patients, rates of IBAX were higher with pancolonic disease. A high proportion of patients with ileal resection or CD affecting ileum or colon had IBAX. IBAX was present even with quiescent inflammation in UC or CD.

CONCLUSIONS

A significant subset of patients with MC, quiescent celiac disease and IBD had increased fecal BA excretion, a potential additional therapeutic target for persistent diarrhea.