Simrén, Magnus

ABSTRACT Background Data on the global prevalence of alarm features in the general population and among individuals with disorders of gut–brain interaction (DGBI) are limited. Methods We analysed data from the Rome Foundation Global Epidemiology Study to estimate the prevalence of fourteen self‐reported alarm features in the global population and among individuals with Rome IV defined DGBI, including 54,127 participants from 26 countries. Differences between participants with and without DGBI were evaluated in a sample excluding those with self‐reported organic gastrointestinal disease, using univariable logistic regression. Analyses were stratified by age (< 50 vs. ≥ 50 years). Results Alarm features were reported by 63.1% of participants aged < 50 years and 51.8% of those aged ≥ 50 years. Individual self‐reported alarm features ranged from 0.9% to 18.3% in younger participants to 0.3%–13.3% in older participants. Haematemesis was the least frequently reported feature, while a major change in bowel movements was the most frequent in both age groups. Self‐reported alarm features were more frequent among participants with than without DGBI (< 50 years: 75.3% vs. 50.7%; OR 3.0 [2.8–3.1]; ≥ 50 years: 67.5% vs. 38.8%; OR 3.3 [3.1–3.5]). Participants with DGBI were also more likely to report multiple alarm features. Discussion Self‐reported alarm features are common in the general population and more prevalent among individuals with DGBI. These findings underscore the importance of interpreting alarm features within a broader clinical context rather than in isolation. Further studies are needed to clarify the diagnostic utility of alarm features in unselected populations, particularly among individuals with DGBI.

INTRODUCTION: Bloating, distention, and gas-related gastrointestinal (GI) symptoms are frequently reported by patients across the spectrum of disorders of gut-brain interaction (DGBI). We aimed to characterize these using latent class modeling in a large multinational survey. METHODS: A nationwide survey of adults in the United States, United Kingdom, and Mexico used quota sampling for demographic balance. It included Rome IV diagnostic questions, Intestinal Gas Questionnaire, Patient Health Questionnaires for anxiety and depression (PHQ-4) and somatization (PHQ-12), quality of life (PROMIS Global-10), and lifestyle questions. Latent class analysis was performed using “depmix” in RStudio 4.2.3. RESULTS: A total of 3,471 subjects experiencing bloating and/or distention (mean age 43 years, 57% female) were included. Using 42 demographic and pertinent clinical variables, latent class analysis revealed 6 distinct clusters. The first 2 clusters demonstrated limited-to-moderate impairment in health-related quality of life (HRQoL), with both characterized by some degree of dietary and supplement associations; however, cluster 2 lacked specific triggers observed in other clusters. The subsequent 2 clusters showed favorable HRQoL and mild gas-related symptoms, with only cluster 4 exhibiting distinct dietary triggers. The final 2 clusters, associated with bowel dysfunction, showed a higher prevalence of irritable bowel syndrome (IBS) with constipation and IBS mixed in cluster 5, and IBS with diarrhea in cluster 6. These bowel dysfunction clusters exhibited severe gas symptoms in the preceding 24 hours and greater HRQoL impairment compared with the other 4 clusters. Notably, cluster 5 was linked to dietary triggers, whereas cluster 6 was defined by psychosocial comorbidities. DISCUSSION: Bloating and distention patients are likely driven by variable influences of dietary, psychological, and bowel dysfunction. Further studies are needed to identify mechanisms and titrate treatment suited to specific mechanistic drivers.

ABSTRACT Introduction Despite the emergence of drugs to treat irritable bowel syndrome (IBS), improving abdominal pain can still be challenging. α 2 δ ligands, such as gabapentin and pregabalin, are sometimes used off‐label to tackle this problem. However, evidence for efficacy is limited, and no large‐scale studies have been published. Aim To study the efficacy of the α 2 δ ligand PD‐217,014 in IBS. Methods This multi‐centre, double‐blind, randomised, placebo‐controlled, parallel group study randomised participants with Rome II‐defined IBS to 150 or 300 mg b.d. of PD‐217,014 or placebo b.d. for 4 weeks. The primary efficacy endpoint was responder, defined as having adequate relief of abdominal pain/discomfort for ≥ 50% of the active treatment period. Key secondary endpoints were change from baseline in abdominal pain, bloating, stool frequency/consistency, and global assessment of IBS symptoms. Results We randomised 330 participants [aged 19–73 years; 209 (65%) female] satisfying Rome II criteria, 322 (98%) were treated, and of whom 271 (84%) completed the study. In this study, 321 satisfied Rome IV criteria. Neither dose of PD‐217,014 improved the percentage of participants reporting adequate relief of abdominal pain/discomfort compared with placebo, either using the Rome II‐defined total cohort or Rome II and IV IBS bowel habit sub‐types. There were similar observations for secondary endpoints, and no association between abdominal pain or anxiety levels at baseline with participant improvement. PD‐217,014 was generally well tolerated. Conclusion This first large, dose‐ranging trial examining the efficacy of PD‐217,014 showed no significant efficacy in participants with IBS or bowel habit sub‐types, irrespective of their pain and anxiety levels.

AbstractBackgroundThere is compelling evidence that microbe‐host interactions in the intestinal tract underlie many human disorders, including disorders of gut‐brain interactions (previously termed functional bowel disorders), such as irritable bowel syndrome (IBS). Small intestinal bacterial overgrowth (SIBO) has been recognized for over a century in patients with predisposing conditions causing intestinal stasis, such as surgical alteration of the small bowel or chronic diseases, including scleroderma and is associated with diarrhea and signs of malabsorption. Over 20 years ago, it was hypothesized that increased numbers of small intestine bacteria might also account for symptoms in the absence of malabsorption in IBS and related disorders. This SIBO‐IBS hypothesis stimulated significant research and helped focus the profession's attention on the importance of microbe‐host interactions as a potential pathophysiological mechanism in IBS.PurposeHowever, after two decades, this hypothesis remains unproven. Moreover, it has led to serious unintended consequences, namely the widespread use of unreliable and unvalidated breath tests as a diagnostic test for SIBO and a resultant injudicious use of antibiotics. In this review, we examine why the SIBO hypothesis remains unproven and, given the unintended consequences, discuss why it is time to reject this hypothesis and its reliance on breath testing. We also examine recent IBS studies of bacterial communities in the GI tract, their composition and functions, and their interactions with the host. While these studies provide important insights to guide future research, they highlight the need for further mechanistic studies of microbe‐host interactions in IBS patients before we can understand their possible role in diagnosis and treatment of patient with IBS and related disorders.

Abstract: Disorders of gastric motor and sensory function affect 10%-20% of the world’s population and adversely impact nutrition, quality of life, work productivity, and health care costs. Classifying these disorders can be challenging given the heterogeneity of symptom presentation, the presence of symptoms unexplained by endoscopic, radiographic and/or laboratory evaluation, and overlap with other luminal gastrointestinal disorders. Accurately diagnosing these highly prevalent disorders relies upon an understanding of epidemiology and risk factors, the ability to take a careful clinical history focused on symptoms, and the presence of predisposing medical, surgical, and psychological conditions. A variety of diagnostic studies are now available to assess gastric motor function and identify maladaptive relaxation, accommodation, and abnormal sensation. FDA-approved treatment options are limited and thus many patients undergo a series of empirical treatment trials that target individual symptoms, often without much benefit. This article provides updated recommendations for identifying and classifying the most common gastric motor and sensory disorders using currently accepted diagnostic tests, and provides a brief supplemental overview on treatment options. “Things sweet to taste prove in digestion sour.” –Shakespeare, Richard II , 1595.

AbstractIrritable bowel syndrome (IBS) is a gut‐brain disorder in which symptoms are shaped by serotonin acting centrally and peripherally. The serotonin transporter gene SLC6A4 has been implicated in IBS pathophysiology, but the underlying genetic mechanisms remain unclear. We sequenced the alternative P2 promoter driving intestinal SLC6A4 expression and identified single nucleotide polymorphisms (SNPs) that were associated with IBS in a discovery sample. Identified SNPs built different haplotypes, and the tagging SNP rs2020938 seems to associate with constipation‐predominant IBS (IBS‐C) in females. rs2020938 validation was performed in 1978 additional IBS patients and 6,038 controls from eight countries. Meta‐analysis on data from 2,175 IBS patients and 6,128 controls confirmed the association with female IBS‐C. Expression analyses revealed that the P2 promoter drives SLC6A4 expression primarily in the small intestine. Gene reporter assays showed a functional impact of SNPs in the P2 region. In silico analysis of the polymorphic promoter indicated differential expression regulation. Further follow‐up revealed that the major allele of the tagging SNP rs2020938 correlates with differential SLC6A4 expression in the jejunum and with stool consistency, indicating functional relevance. Our data consolidate rs2020938 as a functional SNP associated with IBS‐C risk in females, underlining the relevance of SLC6A4 in IBS pathogenesis.

Background and aims The functional gastrointestinal disorders (FGIDs) are extremely common conditions associated with a considerable personal, social and health economic burden. Managing FGIDs in clinical practice is challenging because of the uncertainty of symptom-based diagnosis, the high frequency of overlap between these conditions and the limited efficacy of available therapies. It has often been argued that successful drug development and management of FGIDs requires knowledge of the underlying pathophysiology. Numerous and highly variable candidate pathophysiological mechanisms have been implicated in the generation of FGID symptoms, but there is no current consensus on how to best define the relevance of these disturbances. Methods A group of international experts on FGIDs developed plausibility criteria that should be fulfilled by relevant pathophysiological mechanisms in FGIDs. Results Five criteria are proposed: (1) the presence of the abnormality in a subset of patients, (2) temporal association between proposed mechanism and symptom(s), (3) correlation between the level of impairment of the mechanism and symptom(s), (4) induction of the symptom(s) by provoking the pathophysiological abnormality in healthy subjects and (5) treatment response by a therapy specifically correcting the underlying disorder or congruent natural history of symptoms and dysfunction in the absence of specific therapy. Based on strength of evidence for these five criteria according to the Grading of Recommendations Assessment, Development and Evaluation system, a plausibility score can be calculated for each mechanism. Conclusion Evaluation of the strength of evidence for candidate pathophysiological abnormalities fulfilling these five plausibility criteria will help to identify the most relevant mechanisms to target for novel diagnostic approaches and for the development of new therapies.