Byung Ik Jang

An adequate level of training for technical competence in screening and diagnostic colonoscopy: a prospective multicenter evaluation of the learning curve

BACKGROUND Various training programs in colonoscopy recommend that trainees should perform at least 100 to 200 procedures to be considered technically competent at diagnostic colonoscopy. OBJECTIVE Our purpose was to determine the adequate level of training for technical competence in screening and diagnostic colonoscopy. DESIGN A prospective multicenter trial. SETTING Fifteen tertiary care academic medical centers. PATIENTS Over 8 months we prospectively evaluated the procedures of 24 first-year GI fellows in 15 tertiary care academic medical centers. A total of 4351 colonoscopies were assessed prospectively with variable clinical factors. INTERVENTION Cecal intubation was documented by photographing the identified cecal landmarks, including the appendiceal orifice and the ileocecal valve. MAIN OUTCOME MEASUREMENTS Acquisition of competence (success rate) was evaluated for colonoscopic training on the basis of 2 objective criteria: (1) adjusted completion rate (>90%) and (2) cecal intubation time (<20 minutes). RESULTS The overall success rate was 83.5% (3635/4351). The mean cecal intubation time was 9.23 +/- 4.63 minutes. The success rate significantly improved and reached the requisite standard of competence after 150 procedures (71.5%, 82.6%, 91.3%, 94.4%, 98.4%, and 98.7%, respectively, for every 50 consecutive blocks). The polyp detection rate did not improve significantly during the 8 months and was not correlated with the learning curve. In addition, mean time to cecal intubation decreased significantly, from 11.16 to 8.39 minutes, after 150 procedures. Logistic regression analysis found that prolonged cecal intubation was caused by the following factors: elderly patients, female sex, low body mass index, poor bowel preparation, poor American Society of Anesthesiologists status, abdominal pain as an indication, instructors supervision, and low case volume. LIMITATIONS We did not record final pathologic reports of detected polyps and withdrawal time. CONCLUSIONS Competence in technically efficient screening and diagnostic colonoscopy generally requires experience with more than 150 cases. Also, factors associated with prolonged cecal intubation for typical trainees did not differ from those for experienced colonoscopists.

Genome-wide association study of Crohn's disease in Koreans revealed three new susceptibility loci and common attributes of genetic susceptibility across ethnic populations

Objective Crohns disease (CD) is an intractable inflammatory bowel disease (IBD) of unknown cause. Recent meta-analysis of the genome-wide association studies (GWAS) and Immunochip data identified 163 susceptibility loci to IBD in Caucasians, however there are limited studies in other populations. Methods We performed a GWAS and two validation studies in the Korean population comprising a total of 2311 patients with CD and 2442 controls. Results We confirmed four previously reported loci: TNFSF15, IL23R, the major histocompatibility complex region, and the RNASET2-FGFR1OP-CCR6 region. We identified three new susceptibility loci at genome-wide significance: rs6856616 at 4p14 (OR=1.43, combined p=3.60×10−14), rs11195128 at 10q25 (OR=1.42, combined p=1.55×10−10) and rs11235667 at 11q13 (OR=1.46, combined p=7.15×10−9), implicating ATG16L2 and/or FCHSD2 as novel susceptibility genes for CD. Further analysis of the 11q13 locus revealed a non-synonymous single nucleotide polymorphism (SNP) (R220W/rs11235604) in the evolutionarily conserved region of ATG16L2 with stronger association (OR=1.61, combined p=2.44×10−12) than rs11235667, suggesting ATG16L2 as a novel susceptibility gene for CD and rs11235604 to be a potential causal variant of the association. Two of the three SNPs (rs6856616 (p=0.00024) and rs11195128 (p=5.32×10−5)) showed consistent patterns of association in the International IBD Genetics Consortium dataset. Together, the novel and replicated loci accounted for 5.31% of the total genetic variance for CD risk in Koreans. Conclusions Our study provides new biological insight to CD and supports the complementary value of genetic studies in different populations.

Proton pump inhibitor use and recurrent Clostridium difficile-associated disease: a case-control analysis matched by propensity score.

Background and Aim: Clostridium difficile has been increasingly diagnosed in hospitalized patients. An association between proton pump inhibitors (PPIs) use and Clostridium difficile-associated disease (CDAD) and between recurrent CDAD has been suggested. The aim of this study is to investigate whether PPI use is associated with the development of recurrent CDAD. Methods: This was a retrospective case-control study of patients with CDAD at Yeungnam University Medical Center, seen from January 2004 to December 2008. C. difficile infection was diagnosed by the presence of C. difficile toxin in the stool. Those with recurrent disease were matched with nonrecurrent controls using multivariate matched sampling methods that incorporated the propensity score. Results: Recurrent CDAD developed in 28 (14.1%) of the 198 patients with diarrhea and positive C. difficile stool toxin assays. Multivariate analysis of the total population of recurrent versus nonrecurrent CDAD revealed that additional use of non-C. difficile antimicrobial therapy (concomitant with the treatment or after or both), poor response to therapy with metronidazole or vancomycin, and recent gastrointestinal surgery were risk factors for recurrent CDAD. We were able to match 21 recurrent CDAD subjects with 21 without recurrent CDAD. Among the matched patients only PPI use was associated with recurrent CDAD (ie, 47.6% vs. 4.8%, P=0.004 for recurrent vs. nonrecurrent CDAD, respectively). Conclusions: Among the matched patient groups, only PPI therapy was associated with recurrent CDAD. Prospective studies are needed to clarify whether avoidance of PPIs or specific cotherapies will reduce the incidence of recurrent C. difficile-associated diarrhea.

The prevalence and efficacy of ganciclovir on steroid-refractory ulcerative colitis with cytomegalovirus infection: a prospective multicenter study

Background It remains controversial whether or not cytomegalovirus infection in patients with active ulcerative colitis reflects a nonpathogenic colonization or a pathogenic disease warranting antiviral therapy. Goals The aim of this study was to determine the prevalence of cytomegalovirus infection in patients with active ulcerative colitis and the therapeutic efficacy of ganciclovir against cytomegalovirus infection in patients with steroid-refractory ulcerative colitis. Study A prospective, multicenter study was conducted in 72 patients with moderate-to-severe ulcerative colitis who were treated with intravenous steroids. The presence of cytomegalovirus was evaluated serologically and histopathologic examination, including immunohistochemical staining. In patients with steroid-refractory ulcerative colitis, cytomegalovirus infections were treated with intravenous ganciclovir. In patients with steroid-responsive ulcerative colitis, steroid therapy was continued irrespective of cytomegalovirus infection. Results The evidence of cytomegalovirus infection was found in 31 patients (43%) with moderate-to-severe active ulcerative colitis. In patients with steroid-refractory ulcerative colitis, the cytomegalovirus infection rate increased to 67% (14 of 21). No significant clinical and endoscopic differences existed between patients with and without a cytomegalovirus infection; however, the amount of steroids used during the flare-up period was significantly higher in patients with a cytomegalovirus infection (P=0.013). Eleven of 14 patients (79%) with steroid-refractory ulcerative colitis and a cytomegalovirus infection improved with ganciclovir treatment. Cytomegalovirus infections in the steroid-responsive group (17 of 31) did not require ganciclovir therapy. Conclusions Cytomegalovirus infections are frequently observed in patients with moderate-to-severe ulcerative colitis, especially steroid-refractory ulcerative colitis. Ganciclovir was effective in patients with steroid-refractory ulcerative colitis who had a cytomegalovirus infection.

Capsule endoscopy in small bowel tumors: A multicenter Korean study

Background and Aim:  Capsule endoscopy (CE) has proven to be highly effective at detecting small bowel lesions in a variety of clinical conditions, but studies concerning the practical impact of CE on small bowel tumors are still scarce, especially in the Asian population. The aim of this study was to evaluate the diagnostic and therapeutic impact of CE in the field of small bowel tumors.

Efficacy, safety, and predictors of response to infliximab therapy for ulcerative colitis: A Korean multicenter retrospective study

Infliximab is currently used for the treatment of moderate‐to‐severe ulcerative colitis (UC) with an inadequate response to conventional agents. The efficacy and safety of infliximab in Korean patients with UC were assessed.

Association between acid suppressive therapy and spontaneous bacterial peritonitis in cirrhotic patients with ascites

Abstract Objective. Proton pump inhibitor (PPI) or histamine-2 receptor antagonist (H2RA) therapy may cause intestinal bacterial overgrowth and translocation. Therefore, acid suppressive therapy may increase the risk of spontaneous bacterial peritonitis (SBP) in cirrhotic patients with ascites. Material and methods. A total of 176 cirrhotic patients with ascites who underwent diagnostic paracentesis between September 2004 and April 2009 were included in the analysis. Patients with gastrointestinal hemorrhage and/or antibiotic therapy within 2 weeks prior to hospital admission were excluded. SBP was defined as ≥250/mm3 polymorphonuclear white blood cells with or without a positive culture from the ascitic fluid. Eighty-three patients (mean age 56.1 years, 63 males) had SBP and 93 (mean age 54.7 years, 75 males) did not. Results. On the multivariate analysis, a Child–Pugh class C (OR = 2.890, 95% CI 1.443–5.786; p = 0.003), high MELD scores (≥20, OR = 3.540, 95% CI 1.155–10.849; p = 0.027), and PPI use (OR = 3.443, 95% CI 1.164–10.188; p = 0.025) were risk factors for SBP. H2RA was not associated with SBP. Conclusions. PPI use, as well as Child–Pugh class C and high MELD scores, was an independent risk factor for the development of SBP in cirrhotic patients with ascites. Further prospective studies are warranted to clarify this issue.

The Role of CD44 in the Pathogenesis, Diagnosis, and Therapy of Gastric Cancer.

CD44 is a transmembrane glycoprotein and surface receptor for hyaluronan that is involved in the response of cells to their microenvironment. CD44 splice variants play roles in carcinogenesis, differentiation, and lymph node metastasis and are predictive of the prognosis for various carcinomas, including gastric cancer. Current data suggest that gastric tissue stem cells and gastric cancer stem cells both express the splice variant, CD44v9. Overall, the data regarding the alterations that occur in CD44 and its splice variants in response to acute and chronic infection with Helicobacter pylori are scant and poorly elucidated in terms of possible changes in expression that occur in gastric cancer precursor lesions, such as chronic atrophic gastritis, pyloric metaplasia and intestinal metaplasia. In this study, we discuss the available data and suggest which new data would likely be useful in clinical practice. We also discuss the potential for CD44-targeted therapeutic strategies in gastric cancer. CD44 and its splice variants are positively associated with the initiation and progression of gastric cancer and may also play important roles in diagnosis, therapy and prognosis. CD44 research has been active but fragmented, and it may offer new therapeutic approaches to gastric cancer.

Remission of intestinal Behçet's disease treated with anti-tumor necrosis factor α monoclonal antibody (Infliximab)

Behçets disease (BD) is a chronic relapsing multisystem disease characterized by oral ulceration, genital ulceration and ocular lesions. Gastrointestinal involvement is rare, often difficult to treat and associated with a high mortality rate. We treated a 47-year-old Korean man with BD who had a recurrent intestinal ulcer with tumor necrosis factor α antibody (infliximab); he initially underwent right hemicolectomy due to uncontrolled intestinal bleeding. For patients with intestinal BD who fail to respond to conventional treatment, infliximab may be a safe and effective new therapeutic option.

Efficacy of infliximab in intestinal Behçet's disease: A Korean multicenter retrospective study

Background:Although infliximab is widely accepted as a therapeutic option for inflammatory bowel disease, its therapeutic efficacy for the treatment of intestinal Behçet’s disease (BD) is unknown. We investigated the short-term and long-term response rates to infliximab in intestinal BD and predictive factors of sustained treatment response following infliximab treatment. Methods:This study was conducted using a retrospective noncontrolled review of medical records from 8 tertiary hospitals in Korea. We collected clinical, demographic, and laboratory data for patients with 28 patients with intestinal BD who received at least 1 dose of infliximab. Response rates of infliximab at 2, 4, 30, and 54 weeks for each patient and factors predictive of sustained response were investigated. Adverse events were also identified. Results:The median duration of follow-up after initial infliximab infusion was of 29.5 months. The clinical response rates at 2, 4, 30, and 54 weeks were 75%, 64.3%, 50%, and 39.1%, respectively, with clinical remission rates of 32.1%, 28.6%, 46.2%, and 39.1%, respectively. After multivariate analysis, older age at diagnosis (≥40 yr), female sex, a longer disease duration (≥5 yr), concomitant immunomodulator use, and achievement of remission at week 4 were found to be predictive factors of sustained response. There was 1 serious infection but no malignancies or deaths in this study. Conclusions:Infliximab was a well-tolerated and effective therapy for patients with moderate-to-severe intestinal BD. Moreover, we found 5 predictive factors associated with sustained response, which might assist in optimal patient selection for infliximab treatment.