Korean Inflammatory Bowel Disease Research Articles

Identification of Three Novel Susceptibility Loci for Inflammatory Bowel Disease in Koreans in an Extended Genome-Wide Association Study.

Genome-wide association studies [GWAS] of inflammatory bowel disease [IBD] in multiple populations have identified over 240 susceptibility loci. We previously performed a largest-to-date Asian-specific IBD GWAS to identify two new IBD risk loci and confirm associations with 28 established loci. To identify additional susceptibility loci in Asians, we expanded our previous study design by doubling the case size with an additional dataset of 1726 cases and 378 controls. An inverse-variance fixed-effects meta-analysis was performed between the previous and the new GWAS dataset, comprising a total of 3195 cases and 4419 controls, followed by replication in an additional 1088 cases and 845 controls. The meta-analysis of Korean GWAS identified one novel locus for ulcerative colitis at rs76227733 on 10q24 [pcombined = 6.56 × 10-9] and two novel loci for Crohn's disease [CD] at rs2240751 on 19p13 [pcombined = 3.03 × 10-8] and rs6936629 on 6q22 [pcombined = 3.63 × 10-8]. Pathway-based analysis of GWAS data using MAGMA showed that the MHC and antigenic stimulus-related pathways were more significant in Korean CD, whereas cytokine and transcription factor-related pathways were more significant in European CD. Phenotype variance explained by the polygenic risk scores derived from Korean data explained up to 14% of the variance of CD whereas those derived from European data explained 10%, emphasizing the need for large-scale genetic studies in this population. The identification of novel loci not previously associated with IBD suggests the importance of studying IBD genetics in diverse populations.

Changes in prevalence and perception of complementary and alternative medicine use in Korean inflammatory bowel disease patients: results of an 8-year follow-up survey.

Background/AimsThe use of complementary and alternative medicine (CAM) is a global phenomenon, including inflammatory bowel disease (IBD) patients. We aimed to assess the change in prevalence and patterns of CAM use, and attitudes towards CAM over an 8-year time interval (2006 vs. 2014) among IBD patients in Korea.MethodsA total of 221 IBD patients (CD=142, UC=79) were asked to complete a questionnaire regarding CAM at two time points: at enrollment (2006) and 8 years later (2014/2015).ResultsThe proportion of patients ever using CAM increased significantly from 60.2% in 2006 to 79.6% in 2014 (P<0.001), while the proportion of current CAM users increased slightly (35.7% to 38.0%, P=0.635); 21.7% used CAM consistently at both time points. The proportion of patients who felt CAM was less effective (P<0.001) and more expensive (P=0.04) than conventional treatments increased over time. Also, the proportion among ever CAM users who perceived a positive effect from CAM significantly decreased in 2014 compared to 2006 (P=0.004). Higher education (adjusted odds ratio [aOR], 2.10), prior side effects to conventional therapies (aOR, 2.23), and prior use of corticosteroids (aOR, 2.51) were associated with CAM use. Interestingly, use of CAM before IBD diagnosis (aOR, 2.73) was significantly associated with consistent CAM use.ConclusionsAlthough the attitudes toward CAM have become less favorable, the majority of IBD patients have experienced CAM with an overall increase of current CAM users over time. Moreover, more than half of current CAM users used CAM consistently over time.

Tu1782 – Compositional Changes in the Gut Microbiota of Korean Inflammatory Bowel Disease Patients and the Relationship to Clinical Phenotypes

Tu1782 – Compositional Changes in the Gut Microbiota of Korean Inflammatory Bowel Disease Patients and the Relationship to Clinical Phenotypes

P856 Compositional changes in the gut microbiota of Korean inflammatory bowel disease patients are linked to clinical phenotypes

P856 Compositional changes in the gut microbiota of Korean inflammatory bowel disease patients are linked to clinical phenotypes

What Are the Major Changes in Korean Inflammatory Bowel Disease Surgery?

What Are the Major Changes in Korean Inflammatory Bowel Disease Surgery?

Prevalence of extraintestinal manifestations in Korean inflammatory bowel disease patients

BackgroundThe prevalence of inflammatory bowel disease (IBD) in South Korea is increasing. Although extraintestinal manifestations (EIMs) are an important factor in the clinical outcomes of IBD patients, EIMs have not yet been investigated in Korea. Thus, we conducted a cross-sectional study to assess the prevalence of EIMs in Korean IBD patients.MethodsThe 2014 claims data from the National Health Insurance System (NHIS) of Korea were used. IBD patients were identified by codes for Crohn disease (CD) and ulcerative colitis (UC) in the NHIS registration system for rare or intractable diseases. International Classification of Diseases, Tenth Edition codes were used to identify EIM cases. To estimate the prevalence of EIMs in the general population of Korea, we used national sample data. Standardized prevalence ratios (SPRs) were calculated to compare the prevalence rates of EIMs among IBD patients to those among the general population of Korea.ResultsA total of 13,925 CD patients and 29,356 UC patients were identified. CD and UC patients were different in terms of demographics and utilization of medication. Among the 17 EIMs investigated, pyoderma gangrenosum, osteomalacia, Sweet syndrome, and scleritis were observed in very few patients. The SPRs were greater than 1 for all EIMs. Aphthous stomatitis, rheumatoid arthritis, and osteoporosis were highly prevalent in both CD and UC patients, but the SPRs of the EIMs were not high.ConclusionThe study confirmed that EIMs are more prevalent among IBD patients than among the general population of Korea. The prevalence of EIMs in IBD patients suggests the need for greater attention and effort in clinical practice.

Association of CDKN2A/CDKN2B with inflammatory bowel disease in Koreans.

CDKN2A/CDKN2B locus on 9p21 is reported to be associated with various diseases, including cancer and cardiovascular and inflammatory diseases. Significant downregulation of CDKN2B-AS1 in inflamed colon tissue of inflammatory bowel disease (IBD) cases was reported in Europeans. This study aimed to confirm the suggestive association of CDKN2A/CDKN2B with IBD identified in our recent genome-wide association study (GWAS). We examined the association of CDKN2A/CDKN2B locus with IBD in an additional sample of 574 IBD cases and 542 controls, totaling 4068 cases and 8074 controls. In silico study was performed at various levels for functional annotation of the causal variant. Co-localization of the GWAS association signals and the corresponding expression quantitative trait loci in IBD-related tissues was evaluated using eCAVIAR. An expanded GWAS showed genome-wide significant association of rs3731257 at 9p21 with IBD (odds ratio=1.17, 95% confidence interval=1.12-1.22, Pcombined =5.68×10-9 ) and Crohn's disease (odds ratio=1.22, 95% confidence interval=1.15-1.28, Pcombined =8.85×10-9 ) in the Korean population. Co-localization study suggested that both CDKN2B-AS1 and CDKN2A might be functionally associated with the locus in the small intestine. rs3731257 in CDKN2A/CDKN2B is an IBD-susceptible locus in Koreans, with a suggestive role for small intestine-specific gene regulation. Our findings suggested that alterations of the CDKN2A/CDKN2B locus could affect the pathophysiology of IBD.

P877 Phenotypic and genetic features of mucosa-associated E. coli in Korean inflammatory bowel disease patients

P877 Phenotypic and genetic features of mucosa-associated E. coli in Korean inflammatory bowel disease patients

Overall and cause-specific mortality in Korean patients with inflammatory bowel disease: A hospital-based cohort study.

Limited data are available regarding mortality from inflammatory bowel disease in non-Caucasian populations. Herein, we evaluated overall and cause-specific mortality in a hospital-based cohort of Korean inflammatory bowel disease patients. We determined mortality in 2414 Crohn's disease patients and 2798 ulcerative colitis patients diagnosed between 1977 and 2013. Standardized mortality ratios were calculated in several demographic and phenotypic subgroups. During the mean 9-year follow up, 114 patients died: 35 with Crohn's disease and 79 with ulcerative colitis. The overall standardized mortality ratios were 1.40 (95% confidence interval: 0.97-1.94) in Crohn's disease and 0.73 (0.58-0.91) in ulcerative colitis. In Crohn's disease, female sex, age < 30 years at diagnosis, disease duration > 10 years, ileocolonic disease at diagnosis, perianal fistula, intestinal resection, and ever-use of corticosteroids were associated with higher mortality. In ulcerative colitis, male sex, age ≥ 30 years at diagnosis, disease duration ≤ 5 years, proctitis at diagnosis, and no history of colectomy were associated with lower mortality, while primary sclerosing cholangitis was associated with higher mortality. In both Crohn's disease and ulcerative colitis, high mortality rates due to nonmalignant gastrointestinal causes (standardized mortality ratios: 4.59 and 2.32, respectively) and gastrointestinal malignancies (standardized mortality ratios: 16.59 and 3.45, respectively) were observed. Cardiovascular mortality was lower in ulcerative colitis (standardized mortality ratio: 0.47). The overall mortality tended to be higher in Crohn's disease patients than in the general population; it was slightly lower in ulcerative colitis patients than in the general population.

Identification of Loci at 1q21 and 16q23 That Affect Susceptibility to Inflammatory Bowel Disease in Koreans

Recent genome-wide association studies have identified more than 200 regions that affect susceptibility to inflammatory bowel disease (IBD). However, identified common variants account for only a fraction of IBD heritability and largely have been identified in populations of European ancestry. We performed a genome-wide association study of susceptibility loci in Korean individuals, comprising a total of 1505 IBD patients and 4041 controls. We identified 2 new susceptibility loci for IBD at genome-wide significance: rs3766920 near PYGO2-SHC1 at 1q21 and rs16953946 in CDYL2 at 16q23. In addition, we confirmed associations, in Koreans, with 28 established IBD loci (P < 2.16× 10-4). Our findings support the complementary value of genetic studies in different populations.

P129. Factors associated with anxiety and depression in Korean inflammatory bowel disease patients

P129. Factors associated with anxiety and depression in Korean inflammatory bowel disease patients

P748. Potential role of Fusobacteria in Korean inflammatory bowel disease patients

P748. Potential role of Fusobacteria in Korean inflammatory bowel disease patients

The Clinical Features and Predictive Risk Factors for Reoperation in Patients With Perianal Crohn Diseases; A Multi-Center Study of a Korean Inflammatory Bowel Disease Study Group.

PurposePerianal lesions are common in Crohn disease, but their clinical course is unpredictable. Nevertheless, predicting the clinical course after surgery for perianal Crohn disease (PCD) is important because repeated operations may decrease patient's quality of life. The aim of this study was to predict the risk of reoperation in patients with PCD.MethodsFrom September 1994 to February 2010, 377 patients with PCD were recruited in twelve major tertiary university-affiliated hospitals and two specialized colorectal hospitals in Korea. Data on the patient's demographics, clinical features, and surgical outcomes were analyzed.ResultsAmong 377 patients, 227 patients were ultimately included in the study. Among the 227 patients, 64 patients underwent at least one reoperation. The median period of reoperation following the first perianal surgery was 94 months. Overall 3-year, 5-year, and 10-year cumulative rates of reoperation-free individuals were 68.8%, 61.2%, and 50.5%, respectively. In multivariate analysis (Cox-regression hazard model), reoperation was significantly correlated with an age of onset less than 20 years (hazard ratio [HR], 1.93; 95% confidence interval [CI], 1.07-3.48; P = 0.03), history of abdominal surgery (HR, 1.99; 95% CI, 1.08-3.64; P = 0.03), and the type of surgery. Among types of surgery, fistulotomy or fistulectomy was associated with a decreased incidence of reoperation in comparison with incision and drainage (HR, 0.19; 95% CI, 0.09-0.42; P < 0.001).ConclusionYoung age of onset and a history of abdominal surgery were associated with a high risk of reoperation for PCD, and the risk of reoperation were relatively low in fistulotomy or fistulectomy procedures.

Differences in the adverse effects of azathioprine between inflammatory bowel disease and autoimmune hepatitis in Korean patients.

Azathioprine (AZA) has been widely used in the therapy of inflammatory bowel disease (IBD) and autoimmune hepatitis (AIH). However, studies evaluating the adverse effects of AZA in these two diseases are lacking. The aim of this study was to compare the adverse effects of AZA in Korean IBD and AIH patients. Patients with IBD or AIH who were treated with AZA at Keimyung University Dongsan Medical Center (Daegu, Korea) between January 2002 and March 2011 were enrolled. Their medical records were reviewed retrospectively in terms of clinical characteristics and adverse effects of AZA. A total of 139 IBD patients and 55 AIH patients were finally enrolled. Thirty IBD patients (21.6%) and eight AIH patients (14.5%) experienced adverse effects of AZA. In particular, the prevalence of leukopenia was significantly higher in the IBD group than in the AIH group (p=0.026). T474C mutation was observed in three of 10 patients who were assessed for thiopurine methyltransferase (TPMT) genotype. IBD patients are at increased risk for the adverse effects of AZA compared with AIH patients, of which leukopenia was the most commonly observed. Therefore, IBD patients receiving AZA therapy should be carefully monitored.

Risk Factors for Repeat Abdominal Surgery in Korean Patients with Crohn's Disease: A Multi-Center Study of a Korean Inflammatory Bowel Disease Study Group

PurposeThe purpose of this study was to assess the risk factors for repeated abdominal surgery in Crohn's disease (CD) patients after the first abdominal surgery. Prior studies have tried to identify the risk factors for postoperative recurrence in CD patients, but the results of the studies have been inconsistent. Furthermore, few data on the risk factors for repeated abdominal surgery are available.MethodsClinical data on CD patients who underwent abdominal surgery from January 2000 to December 2009 were collected from seventeen university hospitals and one colorectal clinic. Data from a total of 708 patients were analyzed to find the risk factors for repeated abdominal surgery in CD patients. The mean follow-up period was 72 months.ResultsThe risk of repeated abdominal surgery was 3 times higher in young patients (below 16 years old) than in older patients (odds ratio [OR], 3.056; 95% confidence interval [CI], 1.021 to 9.150); P = 0.046). Stricturing behavior at diagnosis was also a risk factor for repeated abdominal surgery (OR, 2.438; 95% CI, 1.144 to 5.196; P = 0.021). Among operative indications, only intra-abdominal abscess was associated with repeated abdominal surgery (OR, 2.393; 95% CI, 1.098 to 5.216; P = 0.028). Concerning type of operation, an ileostomy might be a risk factor for repeated abdominal surgery (OR, 11.437; 95% CI, 1.451 to 90.124; P = 0.021). Emergency surgery (OR, 4.994; 95% CI, 2.123 to 11.745; P < 0.001) and delayed diagnosis after surgery (OR, 2.339; 95% CI, 1.147 to 4.771; P = 0.019) also increased the risk of repeated abdominal surgery.ConclusionYoung age (below 16 years), stricturing behavior, intra-abdominal abscess, emergency surgery, and delayed diagnosis after surgery were identified as possible risk factors for repeated abdominal surgery in CD patients.

Association of CARD8 with inflammatory bowel disease in Koreans

Caspase recruitment domain (CARD)-containing protein 8 (CARD8) is a potential candidate risk gene for inflammatory bowel disease (IBD) because of its role as a component of the NALP3 inflammasome and as an inhibitor of nuclear factor-kappa B. Previous studies examining the association of a CARD8 single-nucleotide polymorphism (SNP) (rs2043211, p.Cys10X) with IBD yielded mixed results in Caucasians that may result from interaction with NALP3 or NOD2 (nucleotide-binding oligomerization domain 2) variants. To understand the genetic association between CARD8/NALP3 and IBD in Koreans, we investigated seven CARD8, four NALP3 and four NOD2 SNPs in 650 Crohn's disease (CD), 660 ulcerative colitis (UC) patients and 688 controls from the Korean population. rs2043211 of CARD8 showed significant association with UC (P = 0.011; odds ratio = 1.50, 95% confidence intervals = 1.12-2.00, P = 0.006 under recessive model). In contrast, an SNP in intron 1, rs1972619, was associated with CD only (P = 0.033). None of the NALP3 or NOD2 SNPs was significantly associated with CD or UC in the Korean populations. The stop allele of rs2043211 was associated with higher serum interleukin-1β levels only in female patients with UC (P = 0.027). Our data suggest that CARD8 variants might have roles in the pathogenesis of CD and UC in Koreans.

Familial occurrence of inflammatory bowel disease in Korea

Little information is available about the familial aggregation of inflammatory bowel disease (IBD) in Asian populations. We therefore determined the risk of familial aggregation of IBD among first-degree relatives of patients with ulcerative colitis (UC) or Crohn's disease (CD) in an ethnically distinct Korean population. Familial aggregation of IBD was evaluated in terms of family history, prevalence, lifetime risk, and population relative risk in first-degree relatives of 1440 unrelated patients with UC (n = 1043) or CD (n = 397). A positive first-degree family history of IBD was observed in 27 probands (1.88%): 21 of 1043 (2.01%) with UC and 6 of 397 (1.51%) with CD. The crude prevalence of IBD in first-degree relatives of probands with IBD was 0.31%. The lifetime risk of IBD was 0.54% in all first-degree relatives of IBD probands, 0.52% in UC probands, and 0.67% in CD probands, with overall lifetime relative risks of 0.12% in parents, 0.79% in siblings, and 1.43% in offspring. The age- and sex-adjusted population relative risk of IBD was 13.8 in first-degree relatives of probands with IBD. Although a positive family history, prevalence, and lifetime risk of IBD among first-degree relatives of Korean IBD patients are much lower than among relatives of Western patients, the population relative risk in first-degree relatives is about equal in Koreans and Westerners. This finding indicates that a positive family history is an important risk factor for IBD in Koreans and in Westerners.