Irritable bowel syndrome (IBS) is a chronic, disabling, and functional bowel disorder that significantly affects social functioning and reduces quality of life and increases social costs. The Korean Society of Neurogastroenterology and Motility published clinical practice guidelines on the management of IBS based on a systematic review of the literature in 2017, and planned to revise these guidelines in light of new evidence on the pathophysiology, diagnosis, and management of IBS. The current revised version of the guidelines is consistent with the previous version and targets adults diagnosed with or suspected of having IBS. These guidelines were developed using a combination of de novo and adaptation methods, with analyses of existing guidelines and discussions within the committee, leading to the identification of key clinical questions. Finally, the guidelines consisted of 22 recommendations, including 3 concerning the definition and risk factors of IBS, 4 regarding diagnostic modalities and strategies, 2 regarding general management, and 13 regarding medical treatment. For each statement, the advantages, disadvantages, and precautions were thoroughly detailed. The modified Delphi method was used to achieve expert consensus to adopt the core recommendations of the guidelines. These guidelines serve as a reference for clinicians (including primary care physicians, general healthcare providers, medical students, residents, and other healthcare professionals) and patients, helping them to make informed decisions regarding IBS management.

Background/Aims: Ineffective esophageal motility is the most frequent disorder of esophageal peristalsis. Symptoms may include dysphagia, chest pain, and heartburn. Our aims are to evaluate the long-term prognosis and determine if provocative tests during high-resolution esophageal manometry could predict the prognosis. Methods: We retrospectively assessed high resolution manometries performed between 2015-2018 in adult patients. Symptoms were evaluatedat baseline and at follow-up (median 39 months later) using the impact dysphagia questionnaire (IDQ-10), where a score ≥ 7 defined dysphagia, the gastroesophageal reflux disease questionnaire (GerdQ), where a score ≥ 9 defined symptoms of reflux disease and if the subject had chest pain ≥ once a week. Chicago classifications version 3.0 and 4.0 were used. The contractile reserve was assessed by identifying whether esophageal peristalsis normalized or not on solid bolus swallows and a rapid drink challenge was included. Results: Nine hundred and eighty investigations performed during the study period; 114 patients (11.6%) were identified with ineffective esophageal motility. The final study cohort consisted of 33 patients of which 42% had dysphagia at follow-up and 25% had chest pain at least once a week, 46% had reflux symptoms. Patients who normalized motility on solid bolus swallows reported less dysphagia upon follow-up (P = 0.012), nevertheless reported similar proportions of chest pain (P = 0.632), and reflux (P = 0.514).There were no associations between having dysphagia, chest pain, or reflux at follow-up, and abnormal findings on the rapid drinkchallenge (P > 0.05 for all). Conclusions Patients with ineffective esophageal motility continue to experience long-term esophageal symptoms at follow-up. Provocative testsseem to have the potential to partly predict the long-term prognosis of dysphagia.

Background/Aims: Obesity is associated with several gastrointestinal (GI) disorders and has been identified as a potential risk factor for various GI symptoms. Bowel frequency is an important indicator of bowel function. However, the causal link between obesity and gastrointestinal motility remains uncertain. This study aims to determine the causal effect of overall and central obesity on stool frequency. Methods: Four obesity-related anthropometric indicators–body mass index, body fat percentage, waist circumference (WC), and waist-tohip ratio (WHR)–were investigated. Individual-level baseline information from the UK Biobank was used to explore observational associations between obesity and stool frequency. Additionally, summary-level data from published genome-wide association studies were subjected to two-sample Mendelian randomization (MR) analyses to examine causal associations. Results: For all 4 indicators of obesity, higher levels of obesity were associated with more frequent bowel movements after adjusting for demographic characteristics, lifestyle, and dietary factors. After rigorous screening, 482 body mass index single nucleotide polymorphisms (SNPs), 7 body fat percentage SNPs, 48 WC SNPs, and 287 WHR SNPs were identified as instrument variables for MR analysis. The MR results were generally consistent with observational findings, proving that the associations observed in the overall obesity indicators were causal. For central obesity, the association between WHR and stool frequency remained consistent in both analysis phases, whereas WC showed a multidirectional association. Conclusions Obesity-related anthropometric indicators were causally associated with increased stool frequency in the overall and central obesity groups. Weight loss could be a potential approach to improve gastrointestinal regularity in individuals with obesity.

Background/Aims: Rectal hyposensitivity (RH), as defined by the London Classification, has been linked to sensory dysfunction caused by diabetes mellitus and Parkinson’s disease (PD); however, its clinical interpretation has not been sufficiently validated. In this study, we aim to explore the correlations between rectal sensory thresholds and the clinical characteristics of patients with functional defecatory disorders. Methods: We reviewed data from patients who underwent high-resolution anorectal manometry and acquired their clinical characteristics using a standardized questionnaire. The associations between RH based on either 1 (borderline RH) or 2 (RH) abnormal rectal sensory thresholds and patients’ clinical and demographic characteristics were analyzed using linear and logistic regression models in the overall sex-stratified populations. Results: We enrolled 2540 patients, of whom 1046 (41.2%) were men. Overall, 150 (5.9%) patients were diagnosed with RH, whereas 422 (16.6%) had borderline RH. Multivariate linear regression analysis revealed that the Cleveland Clinic Constipation Score (CCCS) increased linearly with the increase in the number of abnormal rectal sensory thresholds (effect per threshold: 0.900 [standard deviation: 0.188]). Upon stratification by sex, borderline RH was positively associated with diabetes mellitus, PD, and CCCS (adjusted odds ratio [aOR] = 2.11, 95% confidence interval [1.08, 4.15]; aOR = 1.49 [1.03, 2.14]; aOR = 1.03 [1.01, 1.05], respectively) in women. However, RH was positively associated with only the CCCS. Conclusions Defining RH based on 1 or more abnormal sensory thresholds showed better clinical correlation with patient characteristics. However, further prospective studies are needed to validate these findings before proposing revisions to the current London classification criteria.

Background/Aims: The association between caffeine intake and constipation remains inconclusive. This study aims to investigate whether caffeine intake is associated with constipation. Methods: This cross-sectional study included 13 941 adults from the 2005-2010 National Health and Nutrition Examination Survey. The weighted logistic regression analyses were exerted to evaluate the association between caffeine intake and constipation. Besides, stratified analyses and interaction tests were conducted to determine the potential modifying factors. Results: After adjusting for confounders, increased caffeine intake by 100 mg was not associated with constipation, as defined by stool frequency (OR, 1.01; 95% CI, 0.94-1.10) or stool consistency (OR, 1.01; 95% CI, 0.98-1.05). Subgroup analyses showed that cholesterol intake modified the relationship between increased caffeine by 100 mg and stool frequency-defined constipation (P for interaction = 0.037). Each 100 mg increase in caffeine intake was associated with a 20% decreased risk of constipation defined by stool frequency in participants who consumed high cholesterol (OR, 0.80; 95% CI, 0.64-1.00), but no association in the other 2 cholesterol level groups. Furthermore, the association between caffeine intake and stool consistency-defined constipation was not found in different cholesterol groups. Conclusions Caffeine consumption is not associated with stool frequency or consistency-defined constipation. Nevertheless, increased caffeine intake may decrease the risk of constipation (defined by stool frequency) among participants in the high-cholesterol intake group.

Background/Aims: Panenteric gastrointestinal dysmotility in diabetic gastroenteropathy remains incompletely understood. We aim to (1) compare gastrointestinal transit times, contractile activity, and pH levels between individuals with and without diabetic gastroenteropathy and (2) investigate associations between symptoms and contractile activity. Methods: We compared 37 healthy individuals to 68 individuals with diabetic gastroenteropathy. Gastrointestinal segmental transit times, contractile activity, and pH were measured with SmartPill. The Gastroparesis Cardinal Symptom Index and the Gastrointestinal Symptom Rating Scale were used to evaluate symptoms. Results: Compared to controls, individuals with diabetic gastroenteropathy had prolonged median gastric emptying time (3.3 [IQR, 2.5-4.4] vs 2.5 [IQR, 1.9-3.6] hours, P = 0.023), antroduodenal transition time (23 [IQR, 8-52] vs 11 [IQR, 2-25] minutes, P = 0.015), colonic transit times (36.0 [IQR, 17.3-53.5) vs 20.8 [IQR, 14.0-28.8] hours, P = 0.004), and whole-gut transit time (46.1 [IQR, 24.3-72.9] vs 28.7 [IQR, 22.0-42.7] hours, P = 0.002). The diabetes group had lower antral contraction frequency (1.5 [IQR, 0.9-2.1] vs 2.5 [IQR, 1.5-3.9] contractions per minute, P = 0.004) and sum of amplitudes (1941 [1377-2763] vs 2975 [1734-5337] mmHg, P = 0.004).In contrast, the diabetes group had higher colonic sum of amplitudes and area under the contraction curve. The antral contraction frequency was unassociated with gastrointestinal symptoms. Still, the overall stomach contraction frequency increased by 30% (P < 0.001) and 15% (P = 0.003) in individuals with diabetes for each incremental increase in nausea and reflux scores, respectively. Conclusions Gastrointestinal transit times, as well as antral and colonic contractile activity, differed between individuals with diabetic gastroenteropathy and controls. The overall gastric contraction frequency was associated with symptom severity.

Background/Aims: Gastric dysrhythmias, loss of normal 3 cycles per minute (CPM) gastric myoelectrical activity (GMA), and variable loss of interstitial cells of Cajal are reported both in gastroparesis (GP) and functional dyspepsia (FD). We hypothesize that the patients with GP, and FD with normal gastric emptying (NGE) and delayed gastric emptying (DGE) may vary in symptom severity, and GMA profiles. Methods: Symptoms and their severity were evaluated by gastroparesis cardinal symptom index (GCSI), Abell scoring, short-form Nepean dyspepsia index (SF-NDI), the World Health Organization quality of life, and Rome IV subtyping for FD. Solid-meal gastric emptying was assessed by nuclear scintigraphy. Water load satiety test (WLST)-based electrogastrography determined GMA. Results: Patients with GP (n = 40) had higher GCSI than those with FD (n = 39; [12 DGE, 27 NGE] (2.79 [2.17-3.33] vs 1.67 [0.83-2.61] vs 0.83 [0.55-1.93]; P < 0.001, in GP vs FD-NGE vs FD-DGE, respectively), severe Abell grade (Grade III in 17 [43%] vs 0% vs 0%, in GP vs FD-NGE vs FD-DGE, respectively), severe SF-NDI (80.5 [63.5-102.5] vs 50 [27-91] vs 30 [21.25-45.5]); and poor QOL. Sixteen (40%) GP had impaired gastric accommodation (< 238 mL). Post-WLST 3 CPM normal/hypernormal GMA was observed in 17 (42%), 18 (67%), and 5 (42%) patients with GP, FD (NGE), and FD (DGE), respectively; and 3 CPM hyponormal in remaining patients in each group.Post-WLST dysrhythmia was comparable. Conclusions WLST-electrogastrography coupled with GE study may distinguish between normal/dysrhythmic GMA revealing pathophysiologicalphenotypes of GP and FD. Analysing extent of power change in normogastric, and dysrhythmic frequencies may comprehensively elucidate disease severity.

Background/Aims: Reflux symptoms frequently present in patients diagnosed with functional dyspepsia (FD). This investigation sought to elucidate the contribution of gastroesophageal reflux in the overlap relationship. Methods: Consecutive patients presenting with reflux symptoms and/or FD symptoms were prospectively included. Comprehensive assessments, including symptoms evaluation, endoscopy, esophageal functional examinations (high-resolution manometry and reflux monitoring), and proton pump inhibitor (PPI) treatment efficacy evaluation, were conducted in these patients. Results: The study enrolled 315 patients, 43.2% of which had concurrent FD symptoms and overlapping reflux symptoms. Notably, a mere 28.7% of patients in the overlap symptoms group had objective gastroesophageal reflux disease evidences (the grade of esophagitis≥ B or the acid exposure time ≥ 4.2%). Functional heartburn was demonstrated to be the main cause of overlapping reflux symptoms(55.1%). Reflux parameters analysis revealed that the reflux burden in the overlap symptoms group paralleled that of the FD symptoms group, with both registering lower levels than the reflux symptoms group (P < 0.05). Furthermore, PPI response rates were notably diminished in the overlap symptoms group (P < 0.001), even for those with objective gastroesophageal reflux disease evidences. Conclusions The study illuminated that overlapping reflux symptoms in FD was common. Strikingly, these symptoms primarily diverged from reflux etiology and exhibited suboptimal responses to PPI intervention. These findings challenge prevailing paradigms and accentuate the imperative for nuanced therapeutic approaches tailored to the distinctive characteristics of overlapping reflux symptoms in the context of FD.

Background/Aims: Globus is often linked with gastroesophageal reflux disease, which influences its treatment strategies. This study aims to investigate clinical characteristics of patients with refractory proton pump inhibitor (PPI) globus to better understand its etiology. Methods: Between 2017 and 2023, 122 out of 592 patients with globus from the Samsung Medical Center outpatient clinic who were unresponsive to 8 weeks of PPI treatment were analyzed. Patients underwent 24-hour esophageal pH monitoring and high-resolution manometry (HRM). They were divided into acid reflux, non-acid reflux, and no reflux groups, with basal impedance (BI) measurements taken at 3, 9, and 15 cm along the esophagus. These values were compared against data of healthy volunteers to identify significant differences across groups. Results: The acid reflux group displayed a median impedance of 1152 Ω at 3 cm, which was significantly lower than the median impedance of the non-acid reflux group (2644 Ω) and the no-reflux group (3083 Ω) (P = 0.015). Most patients in non-acid reflux and no-reflux groups showed higher impedance levels at both 3 cm and 15 cm compared to the first quartile of healthy individuals with significant differences (P = 0.032 and P = 0.029, respectively). Proximal BI was significantly lower than distal BI in both groups: 2278 Ω vs 2644 Ω in the non-acid reflux group (P = 0.035) and 2387 Ω vs 3083 Ω in the no-reflux group (P < 0.001). Conclusions Reduced proximal BI values compared to distal BI values suggest increased permeability in globus patients. Further studies with a larger cohort of refractory PPI patients and healthy volunteers are needed to explore these findings and their implications on globus etiology.