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Crohn’s disease (CD) is a relapsing and progressive condition characterized by diarrhea, abdominal pain, weight loss, and hematochezia that results in serious complications such as perforations, fistulas, and abscesses. Various medications, interventions, and surgical treatments have been used to treat CD. The Korean guidelines for CD management were distributed in 2012 and revised in 2017 by the Inflammatory Bowel Disease (IBD) Research Group of the Korean Association for the Study of Intestinal Diseases. Substantial progress in mucosal immunologic research has elucidated the pathophysiology of IBD, leading to development of biological agents for treatment of CD. The first developed biologic agent, tumor necrosis factor-α agents, were shown to be efficacious in CD, heralding a new era in management of CD. Subsequently, vedolizumab, a monoclonal antibody against integrin α4β7, and ustekinumab, a human monoclonal antibody that inhibits the common p40 subunit of interleukin-12 and interleukin-23, were both approved for clinical use and are efficacious and safe for both induction and maintenance of remission in moderate-to-severe CD patients. Moreover, a recent study showed the non-inferiority of CT-P13, an infliximab biosimilar, compared with infliximab in CD patients. The third Korean guidelines for CD management provide updated information regarding treatment of moderate-to-severe CD patients with biologic agents. [ABSTRACT FROM AUTHOR]

Background/Aims: The long-term course of Crohn’s disease (CD) has never been evaluated in non-Caucasian population-based cohorts. The aim of the present study was to evaluate the longterm prognosis of Korean CD patients in the well-defined population-based Songpa-Kangdong inflammatory bowel disease cohort. Methods: Outcomes of disease and their predictors were evaluated for 418 patients diagnosed with CD between 1986 and 2015. Results: During a median of 123 months, systemic corticosteroids, thiopurines, and anti-tumor necrosis factor (TNF) agents were administered to 58.6%, 81.3%, and 37.1% of patients, respectively. Over time, the cumulative probability of starting corticosteroids significantly decreased (p=0.001), whereas that of starting thiopurines and anti-TNFs significantly increased (both p<0.001). The cumulative probability of behavioral progression was 54.5% at 20 years, and it significantly decreased during the anti-TNF era. Intestinal resection was required for 113 patients (27.0%). The cumulative probabilities of intestinal resection at 1, 5, 10, 20, and 25 years after CD diagnosis were 12.7%, 16.5%, 23.8%, 45.1%, and 51.2%, respectively. Multivariable Cox regression analysis identified stricturing behavior at diagnosis (adjusted hazard ratio [aHR], 2.70; 95% confidence interval [CI], 1.55 to 4.71), penetrating behavior at diagnosis (aHR, 11.15; 95% CI, 6.91 to 17.97), and diagnosis of CD during the anti-TNF era (aHR, 0.51; 95% CI, 0.35 to 0.76) as independently associated with intestinal resection. The standardized mortality ratio among CD patients was 1.36 (95% CI, 0.59 to 2.68). Conclusions: The long-term prognosis of Korean patients with CD is at least as good as that of Western CD patients, as indicated by the low intestinal resection rate. Moreover, behavioral progression and intestinal resection rates have decreased over the past 3 decades. [ABSTRACT FROM AUTHOR]

With advancing analytical methods for gut microbes, many studies have been conducted, revealing that gut microbes cause various diseases, including gastrointestinal and non-gastrointestinal diseases. Accordingly, studies have been actively conducted to analyze the effects on the prevention and treatment of these diseases through changes in intestinal microbes and control of dysbiosis. Fecal microbiota transplantation (FMT) is an effort and is currently being applied to Clostridioides difficile treatment in Korea. Many studies have demonstrated the application of FMT in inflammatory bowel disease, irritable bowel syndrome, non-alcoholic fatty liver disease, metabolic syndrome, obesity, and diabetes. With further studies and accumulation of evidence, FMT could help treat presently untreatable diseases in clinical practice. [ABSTRACT FROM AUTHOR]

Colorectal cancer (CRC) arise from multi-step carcinogenesis due to genetic mutations and epigenetic modifications of human genome. Genetic mutations and epigenetic modifications were originally established as 2 independent mechanisms contributing to colorectal carcinogenesis. However, recent evidences demonstrate that there are interactions between these 2 mechanisms. Genetic mutations enable disruption of epigenetic controls while epigenetic modifications can initiate genomic instability and carcinogenesis. This review summarized genetic mutations and epigenetic modifications in colorectal carcinogenesis and molecular classification of CRC subtype based on genetic or epigenetic biomarkers for treatment response and prognosis. Molecular subtypes of CRC will permit the implementation of precision medicine with better outcome of management for CRC. [ABSTRACT FROM AUTHOR]

Background/Aims: The newly derived simplified magnetic resonance index of activity (MARIAs) has not been verified in comparison to balloon-assisted enteroscopy (BAE) for patients with small bowel Crohn’s disease (CD). We studied the correlation of MARIAs with simple endoscopic scores for CD (SES-CD) of the ileum based on magnetic resonance enterography (MRE) and BAE in patients with small bowel CD. Methods: Fifty patients with small bowel CD who underwent BAE and MRE concurrently within 3 months from September 2020 to June 2021 were enrolled in the study. The primary outcome was the correlation between the active score of ileal SES-CD (ileal SES-CDa)/ileal SES-CD and MARIAs based on BAE and MRE. The cutoff value for MARIAs identifying endoscopically active/ severe disease, defined as ileal SES-CDa/ileal SES-CD of 5/7 or more, was analyzed. Results: Ileal SES-CDa/ileal SES-CD and MARIAs showed strong associations (R=0.76, p<0.001; R=0.78, p<0.001). The area under the receiver operating characteristic curve of MARIAs for ileal SES-CDa ≥5 and ileal SES-CD ≥7 was 0.92 (95% confidence interval, 0.88 to 0.97) and 0.92 (95% confidence interval, 0.87 to 0.97). The cutoff value of MARIAs for detecting active/ severe disease was 3. A MARIAs index value of ≥3 identified ileal SES-CDa ≥5 with a sensitivity of 85% and specificity of 87% and detected ileal SES-CD ≥7 with a sensitivity of 87% and specificity of 86%. Conclusions: This study validated the applicability of MARIAs compared to BAE-based ileal SES-CDa/SES-CD. [ABSTRACT FROM AUTHOR]

Long-standing intestinal inflammation in patients with inflammatory bowel disease (IBD) induces dysplastic change in the intestinal mucosa and increases the risk of subsequent colorectal cancer. The evolving endoscopic techniques and technologies, including dye spraying methods and high-definition images, have been replacing random biopsies and have been revealed as more practical and efficient for detection of dysplasia in IBD patients. In addition, they have potential usefulness in detailed characterization of lesions and in the assessment of endoscopic resectability. Most dysplastic lesions without an unclear margin, definite ulceration, non-lifting sign and high index of malignant change with suspicion for lymph node or distant metastases can be removed endoscopically. However, endoscopic resection of dysplasia in chronic IBD patients is usually difficult because it is often complicated by submucosal fibrosis. In patients with dysplasias that demonstrate submucosa fibrosis or a large size (⩾20 mm), endoscopic submucosal dissection (ESD) or ESD with snaring (simplified or hybrid ESD) is an alternative option and may avoid a colectomy. However, a standardized endoscopic therapeutic approach for dysplasia in IBD has not been established yet and dedicated specialized endoscopists with interest in IBD are needed to fully investigate recent emerging techniques and technologies. [ABSTRACT FROM AUTHOR]

Background/Aims: As the characteristics of inflammatory bowel disease (IBD) differ between Asians and Westerners, it is necessary to determine adequate therapeutic strategy for Asian IBD patients. We evaluated the current treatment of IBD in Asian countries/regions using a web-based survey. Methods: The Korean Association for the Study of Intestinal Diseases conducted a multinational web-based survey for current IBD care in Asia between September 16, 2020, and November 13, 2020. Results: A total of 384 doctors treating IBD patients from 24 Asian countries/regions responded to the survey. Anti-tumor necrosis factor (TNF) agents, anti-integrins, and anti-interleukin-12/23 agents were available for use by 93.8%, 72.1%, and 70.1% of respondents in Asian countries/regions. Compared with a previous survey performed in 2014, an increased tendency for treatment with biologics, including anti-TNF agents, was observed. In the treatment of corticosteroid-refractory acute severe ulcerative colitis, 72.1% of respondents chose anti-TNF agents, followed by tacrolimus (11.7%). In the treatment of corticosteroid-refractory Crohn’s disease, 90.4% chose anti-TNF agents, followed by thiopurines (53.1%), anti-interleukin-12/23 agents (39.3%), and anti-integrin agents (35.7%). In the treatment of Crohn’s disease patients refractory to anti-TNF agents, the most preferred strategy was to measure serum levels of anti-TNF and anti-drug antibodies (40.9%), followed by empiric dose escalation or shortening of dosing intervals (25.3%). Conclusions: Although there were some differences, treatment strategies for patients with IBD were mostly similar among Asian doctors. Based on the therapeutic outcomes, it is necessary to identify the most appropriate therapeutic strategy for Asian IBD patients. [ABSTRACT FROM AUTHOR]

Background: Tofacitinib is a small molecule that inhibits Janus kinase and has been reported to be effective in Western patients with ulcerative colitis (UC). However, the real-life data on tofacitinib in Asian UC patients are limited. Objective: To investigate the real-life effectiveness and safety of tofacitinib induction and maintenance treatment in Korean patients with UC. Design: This was a retrospective study on patients with UC who received tofacitinib treatment at 12 hospitals in Korea between January 2018 and November 2020. Methods: Clinical remission at week 52, defined as a partial Mayo score of ?2 with a combined rectal bleeding subscore and stool frequency subscore of ?1, was used as the primary outcome. Adverse events (AEs), including herpes zoster and deep vein thrombosis, were also evaluated. Results: A total of 148 patients with UC were started on tofacitinib. Clinical remission rates of 60.6%, 54.9%, and 52.8% were reported at weeks 16, 24, and 52, respectively. Clinical response rates of 71.8%, 67.6%, and 59.9% were reported at weeks 16, 24, and 52, respectively. Endoscopic remission rates at weeks 16 and 52 were 52.4% and 30.8% based on the Mayo endoscopic subscore and 20.7% and 15.2% based on the UC endoscopic index of severity (UCEIS), respectively. A higher UCEIS at baseline was negatively associated with clinical response [adjusted odds ratio (aOR): 0.774, 푝=0.029] and corticosteroid-free clinical response (aOR: 0.782, 푝=0.035) at week 52. AEs occurred in 19 patients (12.8%) and serious AEs in 12 patients (8.1%). Herpes zoster occurred in four patients (2.7%). One patient (0.7%) suffered from deep vein thrombosis. Conclusions: Tofacitinib was an effective induction and maintenance treatment with an acceptable safety profile in Korean patients with UC. Real-life effectiveness and safety of tofacitinib treatment in Korean patients with ulcerative colitis Ulcerative colitis (UC) is an idiopathic, chronic inflammatory disorder of the colonic mucosa that usually presents with bloody diarrhea and abdominal pain. Tofacitinib is a small molecule that inhibits Janus kinase and has been reported to be effective in Western patients with UC. However, real-life data on the effectiveness of tofacitinib in Asian patients with UC are limited. To investigate the real-life effectiveness and safety of tofacitinib treatment in Korean patients with UC, we retrospectively analyzed the data of 148 patients with UC who received tofacitinib treatment at 12 hospitals in Korea between January 2018 and November 2020. Clinical remission (i.e. complete improvement of symptoms) was achieved in 60.6% and 52.8% of patients at weeks 16 and 52, respectively. Endoscopic remission was achieved in 52.4% and 30.8% of patients at weeks 16 and 52, respectively. A higher baseline score of the UC endoscopic index of severity, which is one of the endoscopic indices that evaluate the severity of inflammation of the colon, was negatively associated with clinical response (i.e. partial improvement of symptoms). Adverse events (AEs) including herpes zoster and deep vein thrombosis occurred in 19 patients (12.8%) and serious AEs occurred in 12 patients (8.1%). Our real-life study shows that tofacitinib is a clinically effective treatment for Korean patients with UC, and the incidence of AEs was also similar to those observed in other real-world studies. [ABSTRACT FROM AUTHOR]

Background/Aims: The effect of proton pump inhibitors (PPIs) on the lower gastrointestinal (GI) tract is uncertain, with potential to worsen damage. This study aimed to find the best method for protecting the entire GI tract from mucosal damage. Methods: A retrospective cohort study at Samsung Medical Center (2002-2019) included 195,817 patients prescribed GI mucosa-damaging agents. The primary goal was to assess the effectiveness of GI protective agents in preventing significant hemoglobin drops (>2 g/dL), indicating overall GI mucosal damage. Self-controlled case series and landmark analysis were used to address biases in real-world data. Results: The incidence rate ratios for rebamipide, PPI, and histamine-2 receptor antagonist (H2RA) were 0.34, 0.33, and 0.52, respectively. Rebamipide showed a significantly lower incidence rate than H2RA and was comparable to PPIs. Landmark analysis revealed significant reductions in hemoglobin drop risk with rebamipide and H2RA, but not with PPI. Conclusions: Rebamipide, like PPIs, was highly effective in preventing blood hemoglobin level decreases, as shown in real-world data. Rebamipide could be a comprehensive strategy for protecting the entire GI tract, especially when considering PPIs' potential side effects on the lower GI tract. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including proton pump inhibitor therapy, its effects on the human gut microbiota and its side effects on patients of bariatric surgery.

Background/Aims: Limited data are available regarding psychosocial distress at the time of diagnosis of ulcerative colitis (UC). We investigated the psychosocial burden and factors related to poor health-related quality of life (HRQL) among patients newly diagnosed with moderate-to-severe UC who were affiliated with the nationwide prospective cohort study. Methods: Within the first 4 weeks of UC diagnosis, all patients were assessed using the Hospital Anxiety and Depression Scale (HADS), Work Productivity and Activity Impairment questionnaire, Inflammatory Bowel Disease Questionnaire (IBDQ), and 12-Item Short Form (SF-12) health survey. A multiple linear regression model was used to identify factors associated with HRQL. Results: Between August 2014 and February 2017, 355 patients completed questionnaires. Significant mood disorders requiring psychological interventions, defined by a HADS score ≥11, were identified in 16.7% (anxiety) and 20.6% (depression) of patients. Patients with severe disease were more likely to have presenteeism, loss of work productivity, and activity loss than those with moderate disease (all p<0.05). Significant mood disorders had the strongest negative relationship with total IBDQ score, which indicates disease-specific HRQL (β coefficient: –22.1 for depression and –40.0 for anxiety, p<0.001). The scores of all SF-12 dimensions, which indicate general HRQL, were remarkably decreased in the study population compared indirectly with previously reported scores in the general population. The Mayo score, C-reactive protein level, and white blood cell count showed significant negative associations with the IBDQ score (p<0.05). Conclusions: Psychosocial screening and timely interventions should be incorporated into the initial care of patients newly diagnosed with UC. (Gut Liver 2020;14:459- 467) [ABSTRACT FROM AUTHOR]

Background/Aims: The indications for colorectal endoscopic submucosal dissection (ESD) vary in clinical practice. To establish colorectal ESD as a standard treatment, standard indications are essential. For establishing standard indications for colorectal ESD, we surveyed the preferences and criteria of endoscopists for colorectal ESD in their practices. Methods: A multiple-choice questionnaire was sent to 27 members of the Korean Society of Gastrointestinal Endoscopy/ESD group. The indications of endoscopists for selecting ESD as a treatment for colorectal tumors =2 cm in diameter were surveyed. Results: On the basis of the preprocedural assessment of histology, adenoma with high-grade dysplasia, mucosal cancer, and shallow submucosa invasive cancer were included in the indication for ESD. Based on gross morphology, laterally spreading tumor (LST) granular nodular mixed type, LST-nongranular (LST-NG) flat elevated type, and LST-NG pseudodepressed type were included. On the basis of the pit pattern by Kudo classification, types III, IV, and V-I were included. Based on the narrow band imaging pattern by Sano classification, types II and III-a were included. Other lesions, such as sporadic localized tumors in chronic inflammation and local residual early carcinoma after endoscopic resection, were also included in the indication for ESD. Conclusions: The indications of Korean endoscopists for colorectal ESD are broader than those in recent guidelines, and tend to include more benign-looking tumors. To find the appropriate indications for colorectal ESD, systematic data collection and analysis are required to reach a consensus in a timely manner. [ABSTRACT FROM AUTHOR]

Background/Aims: Chronic enteropathy associated with SLCO2A1 gene (CEAS), an inherited disease characterized by nonspecific intestinal ulcers, has emerged in the Japanese population via loss-of-function mutations in the SLCO2A1 gene. We aimed to investigate the clinical and genetic characteristics of Korean patients diagnosed with CEAS. Methods: From July 2018 to July 2021, we performed Sanger sequencing of the SLCO2A1 gene in 46 patients with chronic intestinal ulcers. CEAS was confirmed based on known SLCO2A1 mutations. We summarized the clinical characteristics of patients with confirmed CEAS. Results: Fourteen out of 46 patients (30.4%) had genetically confirmed CEAS, and two SLCO2A1 variants were detected (splicing site variant c.940+1G>A and nonsense mutation [p.R603X] in SLCO2A1). Twelve patients (85.7%) were females and the median age at diagnosis of CEAS was 44.5 years. All patients presented with abdominal pain, and 13 patients (92.9%) presented with anemia (median hemoglobin, 9.6 g/dL). Ten patients (71.4%) had hypoalbuminemia (median, 2.7 g/dL). The most commonly involved site was the ileum (13/14, 92.9%). Manifestations of primary hypertrophic osteoarthropathy (PHO), such as digital clubbing, pachydermia, and periostosis were observed in five patients (28.6%) and two male patients and one female patient satisfied all major PHO diagnostic criteria. Conclusions: The clinical and genetic characteristics of Korean patients with confirmed CEAS were similar to those reported in the literature. CEAS should be considered in the differential diagnosis for patients with unexplained chronic nonspecific ulcers of the small intestine. [ABSTRACT FROM AUTHOR]

Background/Aims: Improving quality of life has been gaining importance in ulcerative colitis (UC) management. The aim of this study was to investigate changes in health-related quality of life (HRQL) and related factors in patients with moderate-to-severe UC. Methods: A multicenter, hospital-based, prospective study was performed using a Moderate-to-Severe Ulcerative Colitis Cohort in Korea (the MOSAIK). Changes in HRQL, evaluated using the 12-Item Short Form Health Survey (SF-12) and Inflammatory Bowel Disease Questionnaire (IBDQ), were analyzed at the time of diagnosis and 1 year later. Results: In a sample of 276 patients, the mean age was 38.4 years, and the majority of patients were male (59.8%). HRQL tended to increase in both the IBDQ and SF-12 1 year after diagnosis. A higher partial Mayo score was significantly related to poorer HRQL on the IBDQ and SF-12 in a linear mixed model (p<0.01). Inflammatory markers such as C-reactive protein (CRP) or erythrocyte sedimentation rate also showed a negative correlation on HRQL (p<0.05). Patients whose IBDQ score improved by 16 or more (71.2%) in 1 year were younger, tended to be nonsmokers, and had a lower partial Mayo score and CRP than those whose IBDQ score did not. There was no significant association between HRQL and disease extent, treatments at diagnosis, or the highest treatment step during the 1-year period. Conclusions: Optimally controlled disease status improves HRQL in patients with moderate-to-severe UC. The partial Mayo score and inflammatory markers may be potential indicators reflecting the influence of UC on patient`s daily lives. [ABSTRACT FROM AUTHOR]

Background/Aims: Our study aimed to evaluate the long-term outcomes and risk factors for relapse after anti-tumor necrosis factor (TNF)-α cessation in inflammatory bowel disease (IBD) patients because they are not well established. Methods: A retrospective multicenter cohort study was conducted involving patients with Crohn’s disease (CD) or ulcerative colitis (UC) from 10 referral hospitals in Korea who discontinued firstline anti-TNF therapy after achieving clinical remission. Results: A total of 109 IBD patients (71 CD and 38 UC) with a median follow-up duration of 56 months were analyzed. The cumulative relapse rates at 1, 3, and 5 years were 11.3%, 46.7%, and 62.5% for CD patients and 28.9%, 45.3%, and 60.9% for UC patients. Multivariable Cox analysis revealed that discontinuation owing to the clinician’s decision was associated with lower risk of relapse (vs patient’s preference: hazard ratio [HR], 0.13; 95% confidence interval [CI], 0.04 to 0.48; p=0.002) and adalimumab use was associated with higher risk of relapse (vs infliximab: HR, 4.42; 95% CI, 1.24 to 17.74; p=0.022) in CD patients. Mucosal healing was associated with lower risk of relapse (vs nonmucosal healing: HR, 0.12; 95% CI, 0.02 to 0.83; p=0.031) in UC patients. Anti-TNF re-induction was provided to 52 patients, and a response was obtained in 50 patients. However, 25 of them discontinued retreatment owing to a loss of response (n=15), the patient’s preference (n=6), and other factors (n=4). Conclusions: More than 60% of IBD patients in remission under anti-TNF therapy relapsed within 5 years of treatment cessation. Anti-TNF re-induction was effective. However, half of the patients discontinued anti-TNF therapy, and 50% of these patients discontinued treatment owing to loss of response. [ABSTRACT FROM AUTHOR]

Background/Aims: We aimed to evaluate the clinical characteristics and long-term prognosis of elderly-onset ulcerative colitis (EOUC) in Korean patients over a 30-year period using a well-established population-based cohort in the Songpa-Kangdong district of Seoul, Korea. Methods: Clinical characteristics and prognosis were compared between two groups: EOUC, defined as UC diagnosed in individuals aged ≥60 years and non-EOUC (N-EOUC), defined as UC diagnosed in individuals aged 18 to 59 years. Results: We identified 99 patients with EOUC (10.3%) and 866 patients with N-EOUC (89.7%) between 1986 and 2015. During the median follow-up of 104.5 months, the overall exposure to medications was comparable between patients with EOUC and N-EOUC (p=0.091 for corticosteroids, p=0.794 for thiopurines, and p=0.095 for anti-tumor necrosis factor agents). The cumulative risks of disease outcomes were also comparable between patients with EOUC and N-EOUC (22.4% vs 30.4% for proximal disease extension [p=0.351], 11.9% vs 18.1% for hospitalization [p=0.240], and 2.3% vs 1.8% for colectomy [p=0.977]) at 10 years after diagnosis. Multivariate Cox regression analysis revealed that corticosteroid use at diagnosis was an independent predictor of proximal disease extension (hazard ratio [HR], 6.216; 95% confidence interval [CI], 1.314 to 28.826) and hospitalization (HR, 11.241; 95% CI, 3.027 to 41.742) in patients with EOUC. Conclusions: In this population-based study from Korea, the pattern of medication use seemed comparable between the EOUC and N-EOUC groups. Moreover, patients with EOUC and those with N-EOUC have a similar disease course in terms of proximal disease extension, hospitalization, and colectomy. [ABSTRACT FROM AUTHOR]

Background/Aims: The treatment goal of ulcerative colitis (UC) has been changed to achieve endoscopic remission (ER). However, there is insufficient clinical evidence to determine whether a step-up treatment should be performed to achieve ER in clinical remission (CR) without ER, and there are inadequate data on the need to consider the distribution and severity of residual inflammation. This retrospective study aimed to evaluate the prognostic significance of the distribution and severity of residual inflammation in UC patients in CR. Methods: A total of 131 UC patients in CR who underwent endoscopic evaluation for more than three times between January 2000 and December 2018 were reviewed. The patients were allocated by the endoscopic healing state and the distribution of inflammation to ER (n=31, 23.7%), residual nonrectal inflammation with patchy distribution (NRI) (n=17, 13.0%) or residual rectal involvement with continuous or patchy distribution (RI) (n=83, 63.3%) groups. We reviewed clinical characteristics, endoscopic findings, and factors associated with poor outcome-free survival (PFS). Results: In UC patients in CR, PFS was significantly higher in the ER and NRI groups than in the RI group (p=0.003). Patients in the ER and NRI groups had similar PFS (p=0.647). Cox proportional hazard model showed only RI (hazard ratio, 5.76; p=0.027) was associated with a higher risk of poor outcome. Conclusions: We suggest that escalation of treatment modalities may be selectively performed in consideration of the residual mucosal inflammation pattern, even if ER has not been achieved, in UC patients with CR. [ABSTRACT FROM AUTHOR]

Background/Aims: Although balloon-assisted enteroscopy (BAE) enables endoscopic visualization of small bowel (SB) involvement in Crohn’s disease (CD), there is no data on the changes in outcomes over time. We therefore investigated the changes in BAE use on CD patients over different time periods in terms of its role and clinical outcomes. Methods: We used a multicenter enteroscopy database to identify CD patients with SB involvement who underwent BAE (131 procedures, 116 patients). We compared BAE-related factors and outcomes between the first period (70 procedures, 60 patients) and the second period (61 procedures, 56 patients). The specific cutoff point for dividing the two periods was 2007, when BAE guidelines were introduced. Results: Initial diagnosis of SB involvement in CD was the most common indication for BAE during each period (50.0% vs 31.1%, p=0.034). The largest change was in the number of BAE uses for stricture evaluation and/or treatment, which increased significantly in the latter period (2.9% vs 21.3%, p=0.002). The diagnostic yield in patients with suspected CD was 90.7% in the first period and 95.0% in the second (p=0.695). More endoscopic interventions were performed in the second period than in the first (5.1% vs 17.6%, p=0.041). Enteroscopic success rates were high throughout (100% in the first period vs 80.0% in the second period, p>0.999). In the first and second periods, therapeutic plans were adjusted in 62.7% and 61.4% of patients, respectively. Conclusions: The overall clinical indications, outcomes, and effectiveness of BAE were constant over time in CD patients with SB involvement, with the exception that the frequency of enteroscopic intervention increased remarkably. [ABSTRACT FROM AUTHOR]

OBJECTIVES: Some neoplastic lesions remain undetected on colonoscopy. To date, no studies have investigated whether combining cap-assisted colonoscopy with chromoendoscopy increases the adenoma detection rate (ADR). This study aimed to compare cap-assisted chromoendoscopy (CAP/CHROMO) with standard colonoscopy (SC) with respect to their efficacy in detecting adenomas. METHODS: This prospective, multicenter, randomized controlled trial included asymptomatic subjects aged 45-75 years who underwent colonoscopy for the first time at 14 university hospitals. Subjects were randomized to either the CAP/CHROMO group (with 0.09% indigo carmine spraying using a capmounted catheter at the tip of the colonoscope) or the SC group. All polyps were resected, but only histologically confirmed neoplastic lesions were considered for analysis. The primary outcome was ADR, defined as the proportion of subjects with at least 1 adenoma. RESULTS: A total of 1,905 subjects were randomized to the CAP/CHROMO (n5948) or SC (n5957) group at 14 centers. Subjects' demographic characteristics were similar between both groups. The CAP/CHROMO group had significantly higher ADR than the SC group (54.4% vs 44.9%, P < 0.001). Significantly, more subjects with at least 1 proximal colon adenoma were identified by CAP/CHROMO (38.6%) than by SC (31.2%) (P 5 0.001). The proximal serrated polyp detection rate by CAP/CHROMO was significantly higher in the female subgroup vs SC. However, advanced ADR was not different between the CAP/CHROMO and SC groups (9.3% vs 7.6%, P 5 0.180). DISCUSSION: CAP/CHROMO markedly improved the ADR and enhanced the detection of proximal adenoma. CAP/CHROMO is feasible for routine application and will allow for a more effective surveillance program. [ABSTRACT FROM AUTHOR]

Background/Aims: The quality of bowel preparation is important for optimal colonoscopy. It is influenced by medical and personal factors. We aimed to evaluate the effect of bowel habit on the quality of bowel preparation and to identify predictors of inadequate bowel preparation among bowel habit factors. Methods: From June 2017 to September 2017, 90 volunteers were enrolled in this study. Each participant answered a questionnaire consisting of multiple questions about personal bowel habits, including stool form, frequency of bowel movements per week, duration, and degree of straining for bowel movement. Then, all volunteers underwent colonoscopic exam. Eleven endoscopists performed colonoscopies and used the Boston Bowel Preparation Scale (BBPS) as the index for bowel preparation. Two expert endoscopists simultaneously reviewed all colonoscopic images to confirm the final BBPS. Univariate and multivariate logistic regression analyses were performed to verify the correlation between bowel preparation adequacy and bowel habit. Results: Among the 90 participants, 20 (22.2%) had inadequate bowel preparation (total BBPS ≤6 or any segmental BBPS ≤1). In univariate analysis, infrequent bowel movement (0-2/week) (odds ratio [OR], 12.60; 95% confidence interval [CI], 1.22 to 129, p=0.03) and moderate straining (more than 1/4 of defecations) (OR, 4.40; 95% CI, 1.44 to 13.39; p=0.01) were significantly associated with inadequate bowel preparation. However, only moderate straining was significantly associated with inadequate bowel preparation in multivariate analysis (OR, 3.99; 95% CI, 1.26 to 12.65; p=0.02). Conclusions: Straining is a significant predictor for inadequate bowel preparation. For patients with straining during bowel movements, an intensified preparation regimen should be considered. [ABSTRACT FROM AUTHOR]

Background/Aims: Gastric cancer evolves in the pathologic mucosal milieu, and its development is characterized by both the loss of acid-secreting parietal cells and mucosal cell metaplasia, called spasmolytic polypeptide-expressing metaplasia (SPEM). Cytokines, such as interleukin (IL)-10, IL-1β, and IL-6, play a key role in gastric carcinogenesis. However, changes in the cytokine profile of SPEM have not been evaluated. Methods: To induce SPEM in mouse stomachs, C57BL/6 mice were intraperitoneally injected with tamoxifen and sacrificed at 3, 10, and 21 days after treatment. RNAsequencing (RNA-seq) and a multiplex bead array were used to measure cytokines in the stomachs of tamoxifen-treated/ control mice. Results: The administration of tamoxifen led to the rapid development and histological normalization of SPEM 3 and 10 days after administration, respectively. RNAseq revealed that the expression of IL-10 was decreased 3 days after tamoxifen administration. The multiplex assay identified a significant decline in IL-10 levels 3 days after tamoxifen treatment (58.38±34.44 pg/mL vs 94.09±4.98 pg/mL, p=0.031), which normalized at 10 and 21 days after tamoxifen treatment. Immunofluorescence staining confirmed that IL-10 expression was markedly decreased at the time of SPEM development and subsequently returned to normal, accompanied by a reversal in histologic changes. Conclusions: IL-10 may play a pivotal role in the tamoxifeninduced acute development of gastric SPEM. [ABSTRACT FROM AUTHOR]

Background/Aims In spite of increased concerns about the overlaps among the various functional gastrointestinal disorders (FGIDs), studies for the overlap between constipation and other common FGIDs are rare. Therefore, we investigated the patterns of overlaps between constipation and other common FGIDs. Methods This study was designed as a prospective nationwide multi-center questionnaire study using Rome III questionnaires for functional dyspepsia (FD), irritable bowel syndrome (IBS), and functional constipation (FC), as well as various questionnaires about patients' information, degree of symptoms, and quality of life. For the evaluation of gastroesophageal reflux disease (GERD), GERD-Q was used. Results From 19 centers, 759 patients with constipation were enrolled. The proportions of FC and IBS subtypes of constipation (IBS-C) were 59.4% and 40.6%, respectively. Among them, 492 (64.8%) showed no overlap. One hundred and thirty-six patients (17.9%) presented overlapping GERD, and 80 patients (10.5%) presented overlapping FD. Fifty one (6.7%) of patients were overlapped by both GERD and FD. Coincidental herniated nucleus pulposus (HNP) (P = 0.026) or pulmonary diseases (P = 0.034), reduced fiber intake (P = 0.013), and laxative use (P < 0.001) independently affected the rate of overlaps. These overlapping conditions negatively affected the constipation-associated quality of life, general quality of life, and degree of constipation. Conclusions The overlap of GERD or FD was common in patients with constipation. Coincidental HNP or pulmonary diseases, reduced fiber intake, and laxatives use were found to be independent associated factors for overlapping common FGIDs in Korean patients with constipation. [ABSTRACT FROM AUTHOR]

Background/Aims: Serrated polyposis syndrome (SPS) has been shown to increase the risk of colorectal cancer (CRC). However, little is known about the characteristics of Asian patients with SPS. This study aimed to identify the clinicopathological features and risk of CRC in Korean patients with SPS as well as the differences between Korean and Western patients based on a literature review. Methods: This retrospective study included 30 patients with SPS as defined by World Health Organization classification treated at Samsung Medical Center, Korea, between March 1999 and May 2011. Results: Twenty patients (67%) were male. The median patient age at diagnosis was 56 years (range, 39-76 years). A total of 702 polyps were identified during a median follow-up of 43 months (range, 0-149 months). Serrated polyps were noted more frequently in the distal colon (298/702, 55%). However, large serrated polyps and serrated adenomas were mainly distributed throughout the proximal colon (75% vs. 25% and 81% vs. 19%, respectively); 73.3% had synchronous adenomatous polyps. The incidence of CRC was 10% (3/30 patients), but no interval CRC was detected. A total of 87% of the patients underwent esophagogastroduodenoscopy and 19.2% had significant lesions. Conclusions: The phenotype of SPS in Korean patients is different from that of Western patients. In Korean patients, SPS is more common in men, there were fewer total numbers of serrated adenoma/polyps, and the incidence of CRC was lower than that in Western patients. Korean patients tend to more frequently have abnormal gastric lesions. However, the prevalence of synchronous adenomatous polyps is high in both Western and Korean patients. [ABSTRACT FROM AUTHOR]

Background/Aims: Studies concerning the efficacy and safety of single-balloon enteroscopy (SBE) compared with that of double-balloon enteroscopy (DBE) often appear to be conflicting. However, previous studies were performed by endoscopists who were less experienced in SBE compared with DBE. Methods: We performed a retrospective analysis of SBE and DBE data performed by a single enteroscopist, with expertise in SBE, using a prospective balloon-assisted enteroscopy registry from 2013 to 2015. Furthermore, we performed a comprehensive literature search and meta-analysis of available studies, including the current study, to clarify the efficacy and safety of SBE versus DBE. Results: A total of 65 procedures in 44 patients with SBE and 74 procedures in 69 patients with DBE were analyzed. There were no significant differences in diagnostic yield (61.1% vs 77.3%, respectively, p=0.397), therapeutic yield (39.1% vs 31.8%, respectively, p=0.548), and complication rate (4.4% vs 2.3%, p=1.000). In the meta-analysis, which included four randomized controlled trials and three observational studies, there were no significant differences in the pooled relative risk and odds ratio for diagnostic and therapeutic yield and complications of SBE compared with those of DBE. Conclusions: The performance of SBE appears to be similar to that of DBE in terms of diagnostic and therapeutic yield and complications. [ABSTRACT FROM AUTHOR]

Background/Aims: The quality of care in inflammatory bowel disease (IBD) has not been systematically estimated. The aim of this study was to investigate the current status of quality of IBD care in Asian countries. Methods: A questionnaire-based survey was conducted between March 2014 and May 2014. The questionnaire was adopted from "An adult inflammatory bowel disease physician performance measure set" developed by the American Gastroenterological Association. If the respondent executed the performance measure in more than 70% of patients, the measure was regarded as well performed. Results: A total of 353 medical doctors from Asia completed the survey (116 from Korea, 114 from China, 88 from Japan, 17 from Taiwan, 8 from Hong-Kong, 4 from India, 3 from Singapore, and 1 each from the Philippines, Malaysia and Indonesia). The delivery of performance measures, however, varied among countries. The documentation of IBD and tuberculosis screening before anti-tumor necrosis factor therapy were consistently performed well, while pneumococcal immunization and prophylaxis of venous thromboembolisms in hospitalized patients were performed less frequently in all countries. Physician awareness was positively associated with the delivery of performance measures. Variations were also noted in reasons for non-performance or low performance of quality measures, and the two primary reasons cited were consideration of the measure to be unimportant and lack of time. Conclusions: The delivery of performance measures varies among physicians in Asian countries, and reflects variations in the quality of care among the countries. This variation should be recognized to improve the quality of care in Asian countries. [ABSTRACT FROM AUTHOR]

The Korean Society of Neurogastroenterology and Motility first published guidelines for chronic constipation in 2005 and was updated in 2011. Although the guidelines were updated using evidence-based process, they lacked multidisciplinary participation and did not include a diagnostic approach for chronic constipation. This article includes guidelines for diagnosis and treatment of chronic constipation to realistically fit the situation in Korea and to be applicable to clinical practice. The guideline development was based upon the adaptation method because research evidence was limited in Korea, and an organized multidisciplinary group carried out systematical literature review and series of evidence-based evaluations. Six guidelines were selected using the Appraisal of Guidelines for Research & Evaluation (AGREE) II process. A total 37 recommendations were adopted, including 4 concerning the definition and risk factors of chronic constipation, 8 regarding diagnoses, and 25 regarding treatments. The guidelines are intended to help primary physicians and general health professionals in clinical practice in Korea, to provide the principles of medical treatment to medical students, residents, and other healthcare professionals, and to help patients for choosing medical services based on the information. These guidelines will be updated and revised periodically to reflect new diagnostic and therapeutic methods. [ABSTRACT FROM AUTHOR]

Intestinal tuberculosis (ITB) remains prevalent in Asia. An interferon-γ assay (QuantiFERON-TB gold test [QFT]) is considered to be an effective supplementary tool for diagnosing ITB. We retrospectively analyzed the clinical features of ITB patients based on the initial results of QFT. A total of 109 patients with ITB were enrolled, and 82 patients (75.2%) showed positive QFT results. In the QFT-positive group, the mean age (44.1±12.0 years) was significantly higher than that in the QFT-negative group (37.0±14.8, p=0.0096). Abdominal pain (p=0.006) and diarrhea (p=0.030) were more frequent in the QFT-negative group. Further, C-reactive protein (CRP) levels were significantly higher in the QFTnegative group (6.4±9.9 mg/dL) than in the QFT-positive group (1.3±2.3, p<0.001). Multivariate analysis confirmed that younger age (p=0.016), diarrhea (p=0.042), and high levels of CRP (p=0.029) were independent predictors of QFTnegative results in patients with ITB. These results suggest that prior exposure to TB, reflected by QFT positivity, may cause mild inflammation in patients with ITB. [ABSTRACT FROM AUTHOR]

Micronutrient deficiencies in Crohn's disease (CD) patients are not uncommon and usually result in a combination of reduced dietary intake, disease-related malabsorption, and a catabolic state. Decreased serum thiamine levels are often reported in patients with CD. Wernicke's encephalopathy (WE) is a severe form of thiamine deficiency that can cause serious neurologic complications. Although WE is known to occur frequently in alcoholics, a number of non-alcoholic causes have also been reported. Here, we report two cases of non-alcoholic WE that developed in two severely malnourished CD patients who were supported by prolonged total parenteral nutrition without thiamine supplementation. These patients complained of sudden-onset ophthalmopathy, cerebellar dysfunction, and confusion. Magnetic resonance imaging allowed definitive diagnosis for WE despite poor sensitivity. The intravenous administration of thiamine alleviated the symptoms of WE dramatically. We emphasize the importance of thiamine supplementation for malnourished patients even if they are not alcoholics, especially in those with CD. [ABSTRACT FROM AUTHOR]

Enteropathy-associated T-cell lymphoma (EATL) is a rare extranodal T-cell lymphoma arising from the intestine. Two types of EATL have been reported. In contrast to the classic EATL type I, EATL type II occurs sporadically, is unrelated to celiac disease, and comprises 10% to 20 % of all EATL cases. A total of five cases of EATL type II were diagnosed at our clinic from January 2009 to September 2012. Four of the five patients were diagnosed with the help of endoscopy. Among the four patients, two of the cases involved both the small and large intestines, whereas in the other two patients, EATL was limited to the small intestine. Common endoscopic findings included innumerable fine granularities (also called mosaic mucosal patterns) and diffuse thickening of the mucosa with a semicircular shallow ulceration in the lesions of the small bowel. In contrast, the endoscopic findings of the colon were nonspecific and could not distinguish EATL type II from other diseases. There are only few published reports regarding the representative endoscopic findings of EATL. Here, we present the clinical and endoscopic findings of four cases of EATL type II diagnosed by endoscopy. [ABSTRACT FROM AUTHOR]

Background/Aims: Colorectal adenomas that are ≥10 mm have villous histology or high-grade dysplasia, or that are associated with ≥3 adenomas are considered high-risk for metachronous advanced neoplasia. We evaluated the cumulative incidence of metachronous advanced neoplasia according to the total number of high-risk findings detected on baseline colonoscopy. Methods: This was a retrospective cohort study performed in 862 patients who underwent removal of colorectal adenomas between 2005 and 2009. At least one surveillance colonoscopy had been conducted at Konkuk University Medical Center, Seoul, Korea. Results: The cumulative incidence of metachronous advanced neoplasia in patients with 0, 1, 2, and 3-4 high-risk findings at 1 year were 0.7%, 1.3%, 2.8%, and 8.0%; at 3 years, those were 5.9%, 11.9%, 15.5%, and 24.7%; and at 5 years, those were 8.5%, 18.7%, 26.3%, and 37.2%, respectively. In a multivariate model, the risk of metachronous advanced neoplasia was significantly higher for the multiple high-risk findings group when compared with the 0 high-risk findings group (1 high-risk (+): hazard ratio, 1.86 [95% confidence interval, 1.00-3.44]; 2 high-risk (+): 1.84 [0.88-3.84]; and 3-4 high-risk (+): 3.29 [1.54-7.01]; ptrend=0.020). Conclusions: The presence of overlapping multiple high-risk findings was associated with an increased risk of advanced neoplasia during surveillance. [ABSTRACT FROM AUTHOR]

Background/Aims: A diagnosis of acute diverticulitis is based on computed tomography (CT). Colonoscopy is commonly performed after the acute event to exclude other diagnoses. This study aimed to determine whether colonoscopy is necessary and what additional information is gained from a colonoscopy after acute diverticulitis. Methods: Acute diverticulitis was diagnosed by clinical criteria and characteristic CT findings. We analyzed the number of patients in whom colorectal cancers were diagnosed and other incidental findings of polyps and other diseases. Results: A total of 177 patients were analyzed retrospectively. The mean age was 43.3±15.3 years (range, 13-82 years) and 97 patients (54.8%) were male. Sixty-one patients had undergone a colonoscopy within 1 year of the acute attack. Advanced adenomatous lesions and colonic malignancy were not detected. Nineteen patients (31.1%) had =1 polyp and 11 patients (18.0%) had an adenomatous polyp. No new or different diagnosis was made after colonoscopy. None of the 116 patients who did not undergo colonoscopy within a year after acute diverticulitis had a diagnosis of colorectal cancer registered with the Korea Central Cancer Registry. Conclusions: Routine colonoscopy yields little benefit in patients with acute diverticulitis diagnosed by typical clinical symptoms and CT. The current practice of a colonoscopy after acute diverticulitis needs to be reevaluated. [ABSTRACT FROM AUTHOR]

Background/Aims: The expression of sonic hedgehog (Shh) in the colon cancer cell has been implicated in colorectal carcinogenesis. However, the association between Shh expression in the normal colonic mucosa and the recurrence of colorectal neoplasm after tumor resection has not been well documented. The aim of the study was to determine the association between Shh expression in the normal colonic mucosa and in the recurrence of colorectal neoplasm. Methods: Fifty-five patients who underwent a long-term follow-up colonoscopy after the colorectal neoplasm resection were included. At the time of the tumor resection, Shh expression in the normal colonic mucosa was examined. The association between Shh expression in the normal colonic mucosa and the recurrence of colorectal neoplasm was analyzed. Results: In total, 97 colorectal neoplasms were detected among 41 subjects after a mean follow-up period of 63 weeks (range 27-254 weeks). Of 55 subjects, 26 (47.3%) exhibited positive Shh expression in the normal colonic tissue, and the recurrence rate did not differ with the degree of Shh expression (P=0.238). The degree of Shh expression was not associated with the number (P=0.389), size (P=0.928), location (P=0.410), pathologic types (P=0.127), or time of recurrence (P=0.711) of the recurred colorectal neoplasm. Conclusions: Most colorectal neoplasm patients show recurrence after the resection and exhibit Shh expression in the normal colonic tissue. The degree of Shh expression in the normal colonic mucosa does not predict the recurrence of colorectal neoplasm. [ABSTRACT FROM AUTHOR]

Background/Aims: The semiquantitative parameter "standard uptake value" (SUV) of 18Fluorodeoxyglucose (FDG) positron-emission tomography (PET) provides important additional information about colorectal cancer. In general, colorectal cancers exhibit different growth patterns with different clinicopathological characteristics. The aim of this study was to elucidate the link between the macroscopic appearance of colorectal cancers and maximum SUV (SUVmax) FDG uptakes. Methods: We analyzed 347 patients with colorectal cancer who underwent PET scanning before treatment. The SUVmax of colorectal cancer was analyzed by examining PET images. The macroscopic appearance of each colorectal cancer was classified into three major types: ulcerofungating (n=223), ulceroinfiltrating (n=44), and fungating (n=78). Two cases that were difficult to classify were excluded from the study. Results: The SUVmax was higher in colorectal cancers with an ulcerofungating appearance (12.19±5.84, mean±standard deviation) and ulceroinfiltrating appearance (11.66±5.63) than in those with a fungating appearance (9.58±6.67; P=0.005) (ulcerofungating and ulceroinfiltrative vs. fungating, P<0.001). A smaller tumor size (P<0.001) were significantly related to the fungating colorectal cancer. Four out of six colorectal cancers that did not show FDG uptake were the fungating type. Conclusions: Colorectal cancers with a fungating appearance exhibit a lower SUVmax, shallower invasion and smaller tumor size. Our results indicate that colorectal cancers with a fungating appearance would be less prominent on PET scan than those with an ulcerofungating or ulceroinfiltrating appearance, and thus require more attention. [ABSTRACT FROM AUTHOR]

Background/Aims Despite of proven efficacy of anti-tumor necrosis factor-α (anti-TNF) for inflammatory bowel disease (IBD), some patients have to discontinue it for various reasons in a real-world. This study aimed to evaluate long-term outcomes and risk factors of relapse after discontinuation of anti-TNF in IBD patients with clinical remission. Methods A retrospective cohort study was conducted at 10 referral hospitals, affiliated in IBD Study Group of Korean Association for the Study of Intestinal Diseases. The study population comprised Crohn's disease (CD) or ulcerative colitis (UC) patients, treated with anti- TNF (infliximab [IFX] or adalimumab [ADA]) to induce remission and in whom anti-TNF had been discontinued after clinical remission. The patients were excluded for follow-up of <12 months after discontinuation. Results The 125 IBD patients were eligible, and then 109 patients (71 CD and 38 UC) were analyzed and median follow-up period was 56 months. The reasons of discontinuation of anti-TNF was physician's decision (29.4%), patient's own preference (27.5%), adverse events/opportunistic infection (16.5%), and other reasons (26.6%). Relapse rate at 1 and 5 years in CD was 11.3%, and 62.5% and that in UC was 28.9% and 60.9%. Multivariate Cox regression analysis identified risk of relapse was associated with ADA use (vs IFX: hazard ratio [HR], 3.65; 95% confidence interval [CI], 1.03 to 13.02) and discontinuation due to physician's decision (vs patient's preference: HR, 0.14; 95% CI, 0.04 to 0.48) in CD, whereas that was decreased in UC with mucosal healing (vs non-mucosal healing: HR, 0.07; 95% CI, 0.01 to 0.55). Retreatment with anti-TNF was done in 52 patients and effective in 44 patients. Conclusions Discontinuation of anti-TNF was associated with increased risk of relapse. Although retreatment of anti-TNF seems to be effective and safe, discontinuation should be carefully considered based on anti-TNF type, reason of discontinuation, and mucosal healing status. [ABSTRACT FROM AUTHOR]