Background/Aims: The fecal microbiota of Korean patients with inflammatory bowel disease (IBD) was investigated with respect to disease phenotypes and taxonomic biomarkers for diagnosis and prognosis of IBD.Methods: Fecal samples from 70 ulcerative colitis (UC) patients, 39 Crohn’s disease (CD) patients, and 100 healthy control individuals (HC) were collected. The fecal samples were amplified via polymerase chain reaction and sequenced using Illumina MiSeq. The relationships between fecal bacteria and clinical phenotypes were analyzed using the EzBioCloud database and 16S microbiome pipeline.Results: The alpha-diversity of fecal bacteria was significantly lower in UC and CD (<i>P</i><0.05) compared to that in HC. Bacterial community compositions in UC and CD were significantly different from that of HC according to Bray-Curtis dissimilarities, and there was also a difference between community composition in UC and CD (<i>P</i>=0.01). In UC, alpha-diversity was further decreased when the disease was more severe and the extent of disease was greater, and community composition significantly differed depending on the extent of the disease. We identified 9 biomarkers of severity and 6 biomarkers of the extent of UC. We also identified 5 biomarkers of active disease and 3 biomarkers of ileocolonic involvement in CD. <i>Lachnospiraceae</i> and <i>Ruminococcus gnavus</i> were biomarkers for better prognosis in CD.Conclusions: The fecal microbiota profiles of IBD patients were different from those of HC, and several bacterial taxa may be used as biomarkers to determine disease phenotypes and prognosis. These data may also help discover new therapeutic targets for IBD.

Background/Aims: The prospective Crohn's Disease Clinical Network and Cohort Study is a nationwide multicenter cohort study of patients with Crohn's disease (CD) in Korea, aiming to prospectively investigate the clinical features and long-term prognosis associated with CD.Methods: Patients diagnosed with CD between January 2009 and September 2019 were prospectively enrolled. They were divided into two cohorts according to the year of diagnosis: cohort 1 (diagnosed between 2009 and 2011) versus cohort 2 (between 2012 and 2019). Results: A total of 1,175 patients were included, and the median follow-up duration was 68 months (interquartile range, 39.0 to 91.0 months). The treatment-free durations for thiopurines (p<0.001) and anti-tumor necrosis factor agents (p=0.018) of cohort 2 were shorter than those of cohort 1. Among 887 patients with B1 behavior at diagnosis, 149 patients (16.8%) progressed to either B2 or B3 behavior during follow-up. Early use of thiopurine was associated with a reduced risk of behavioral progression (adjusted hazard ratio [aHR], 0.69; 95% confidence interval [CI], 0.50 to 0.90), and family history of inflammatory bowel disease was associated with an increased risk of behavioral progression (aHR, 2.29; 95% CI, 1.16 to 4.50). One hundred forty-one patients (12.0%) underwent intestinal resection, and the intestinal resection-free survival time was significantly longer in cohort 2 than in cohort 1 (p=0.003). The early use of thiopurines (aHR, 0.35; 95% CI, 0.23 to 0.51) was independently associated with a reduced risk of intestinal resection. Conclusions:The prognosis of CD in Korea appears to have improved over time, as evidenced by the decreasing intestinal resection rate. Early use of thiopurines was associated with an improved prognosis represented by a reduced risk of intestinal resection.

Background/Aims: Low-volume preparations for colonoscopy are gaining attention for their higher acceptability. However, the efficacy and safety of oral sulfate solution (OSS) preparations in patients with ulcerative colitis (UC) has not been well known. Therefore, we aimed to compare OSS and 2-L polyethylene glycol with ascorbic acid (PEG+Asc) for bowel preparation in inactive UC.Methods: A multicenter, randomized, single-blind study was conducted at six tertiary referral hospitals in Korea. Outpatients with UC who had stable disease activity were randomly allocated to the OSS group or the 2-L PEG+Asc group for bowel preparation before colonoscopy. The study outcomes included treatment efficacy, safety, tolerability, and acceptability. Bowel cleansing was assessed using the Boston Bowel Preparation Scale and rated as successful cleansing if the score was ≥6. Patient acceptance and tolerability were assessed using a 4-point ordinal scale. Additionally, disease activity and laboratory data before and after colonoscopy were evaluated to check for safety. Results:The OSS and 2-L PEG+Asc groups included 92 and 93 participants, respectively. No significant between-group difference was noted in successful cleansing (OSS [96.7%] vs 2-L PEG+Asc [97.8%], p=0.64). Moreover, the safety, acceptance, and tolerability were not significantly different (all p>0.05). Furthermore, no significant changes were found in serum electrolytes or disease activity in either group. Conclusions:OSS is effective for colonoscopy cleansing, has acceptable tolerability, and does not affect disease activity; thus, it can be used safely for bowel preparation in patients with inactive UC.

Background/Aims: The clinical efficacy and safety of CT-P13 are comparable to originator infliximab for Crohn's disease in CT-P13 3.4 study (NCT02096861). We performed a multivariate logistic analysis to demonstrate the association between early infliximab trough levels and treatment outcomes of CT-P13 and originator infliximab. Methods:Early serum infliximab trough levels and anti-drug antibody (ADA) levels were compared between CT-P13 (n=100) and originator infliximab (n=98) groups. Receiver operating characteristic (ROC) analysis and multivariate logistic analysis were conducted to identify optimal cutoffs of serum infliximab trough levels and predictive factors for clinical outcomes. Results:The median infliximab trough levels were not different between CT-P13 and originator infliximab groups at week 6, week 14, and in median ADA levels at week 14, respectively. ROC analysis found an infliximab concentration threshold of 4.5 μg/mL at week 6 and 4.0 μg/mL at week 14 as the cutoff value with the highest accuracy for the prediction of clinical outcomes. Serum infliximab trough levels at weeks 6 and 14 predicted clinical remission at weeks 30 and 54, and endoscopic remission at week 54. The combinations of clinical remission or C-reactive protein normalization with an early infliximab trough level improved the prediction of long-term clinical or endoscopic remission. Conclusions:A threshold in serum infliximab trough level at week 6 and week 14 was highly predictive for long-term clinical outcomes. There were no statistical differences in serum infliximab trough levels and ADA levels between CT-P13 and originator infliximab.

Background. Patients with inflammatory bowel disease (IBD) have a decreased quality of life (QoL), the improvement of which is a treatment goal. The CUCQ-8 is a verified simple and effective QoL measurement tool. We validated the Korean version of CUCQ-8 with the approval of its developer. Methods. We investigated the correlation between the Korean version of CUCQ-8 and the IBDQ-32 in patients with IBD. Results. In all, 147 subjects (male, 97 (66.0%); female, 50 (34.0%); mean age 36.2 ± 13.5 years) were analyzed. Cronbach’s alpha coefficient of the CUCQ-8 was 0.833, indicating very high internal consistency. The Korean version of the CUCQ-8 showed a significant correlation with the IBDQ-32 and its subscales (correlation coefficient, >0.75). Conclusions. The Korean version of the CUCQ-8 has high reliability and construct validity and can be used to evaluate the QoL of patients with IBD.