Publications by authors named "Dong K Chang"

Background: Predose trough concentrations (C) of intravenous infliximab (IV-IFX) during maintenance therapy are associated with therapeutic outcomes in patients with Crohn's disease (CD). A subcutaneous formulation of infliximab (SC-IFX) has shown high C values due to its favourable pharmacokinetics.

Aims: To evaluate the association of C of SC-IFX with therapeutic outcomes and the threshold of SC-IFX C for achieving mucosal healing (MH) and transmural healing (TH) in patients with CD.

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Infliximab (IFX) has transformed the management of inflammatory bowel diseases (IBD). While intravenous (IV) IFX has been effective, a subcutaneous (SC) formulation offers advantages in convenience and cost. However, there is lack of evidence regarding the transition from IV to SC-IFX, especially for patients with inadequate responses.

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Limited research has been performed to determine if histologic improvement serves as a prognosticator for endoscopic remission, a key therapeutic target for ulcerative colitis (UC). The primary aim of the study was to evaluate if histological activity could predict endoscopic remission in UC patients with Mayo endoscopic subscores (MES) of 0 or 1. In addition, we compared the clinical outcomes between histologic improvement group and active group.

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Introduction: Endoscopic submucosal dissection (ESD) has been popular worldwide to treat laterally spreading tumors and large polyps. Post-ESD coagulation syndrome (PECS) is more common than the two major ESD-related complications, perforation, and bleeding. The aim of this study was to assess the prevalence of PECS, identify the risk factors for PECS, and create a risk prediction model for PECS.

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Background/aims: Colonoscopy is commonly used for colorectal cancer screening; therefore, the detection of colon subepithelial tumors (SETs) has also increased. Several research studies have been undertaken to diagnose and treat stomach and rectal SETs. The purpose of this study was to determine a diagnostic point for colon SETs by comparing histological findings with the endoscopic characteristics of colon SETs discovered by chance.

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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.

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Background And Aims: Diagnostic colonoscopy plays a central role in colorectal cancer screening programs. We analyzed the risk factors for perforation during diagnostic colonoscopy and discussed the treatment outcomes.

Methods: We performed a retrospective analysis of risk factors and treatment outcomes of perforation during 74,426 diagnostic colonoscopies between 2013 and 2018 in a tertiary hospital.

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Background: While primary intestinal lymphangiectasia (PIL) is considered a rare condition, there have been several reported cases in adults. Nevertheless, the absence of clear guidance from diagnosis to treatment and prognosis poses challenges for both physicians and patients.

Aim: To enhance understanding by investigating clinical presentation, diagnosis, treatment, complications, and prognoses in adult PIL cases.

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Background: The incidence of colorectal cancer (CRC) and preinvasive CRC (., early colon cancer and advanced adenoma) is gradually increasing in several countries.

Aim: To evaluate the trend in incidence of CRC and preinvasive CRC according to the increase in the number of colonoscopies performed in Korea.

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Article Synopsis
  • The study investigated how the tilt of the optic disc affects classification models based on deep learning using 2507 fundus photographs from 1809 subjects.
  • Results showed that models trained on images of non-tilted optic discs performed significantly better (higher area under the curve) compared to those trained on tilted discs.
  • The findings highlight the importance of accounting for optic disc tilt when developing classification algorithms for better accuracy in diagnosing eye conditions.
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A knowledgebase (KB) transition of a clinical decision support (CDS) system occurred at the study site. The transition was made from one commercial database to another, provided by a different vendor. The change was applied to all medications in the institute.

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Malnutrition might play a key role in the prognosis of patients with Crohn's disease (CD). The aim of this study was to explore the impact of weight loss from diagnosis of CD to one-year post-diagnosis on disease prognosis in terms of surgery. Patients who were diagnosed with CD at Samsung Medical Center between 1995 to 2020 were included in this study.

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There are limited studies on the endoscopic assessment of disease activity using balloon-assisted enteroscopy (BAE) and its predictive role for long-term outcomes of patients with small bowel Crohn's disease (CD). We sought to investigate the value of BAE as a predictor of long-term outcomes in patients with small-bowel CD. A total of 111 patients with small-bowel CD whose endoscopic disease activity was assessed using BAE based on the small-bowel simple endoscopic score for Crohn's disease (small-bowel SES-CD) at Samsung Medical Center were retrospectively selected from January 2014 to August 2020.

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Background: This study aimed to determine short-term and long-term outcomes according to time intervals after stenting and compared them with those of emergency surgery (ES) in colorectal cancer (CRC) with malignant obstruction.

Methods: CRC with malignant obstructions was reviewed retrospectively between January 2008 and July 2018. Of a total of 539 patients who visited the emergency room and underwent ES, 133 were enrolled in the ES group.

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The aim of this study was to address the issue of differentiating between Mayo endoscopic subscore (MES) 0 and MES 1 using a deep learning model. A dataset of 492 ulcerative colitis (UC) patients who demonstrated MES improvement between January 2018 and December 2019 at Samsung Medical Center was utilized. Specifically, two representative images of the colon and rectum were selected from each patient, resulting in a total of 984 images for analysis.

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Article Synopsis
  • The study aimed to compare the newly derived simplified magnetic resonance index of activity (MARIAs) against balloon-assisted enteroscopy (BAE) for assessing small bowel Crohn's disease.
  • Fifty patients undergoing BAE and magnetic resonance enterography (MRE) were analyzed, focusing on the correlation between MARIAs and the endoscopic scores (SES-CD) for disease activity.
  • MARIAs proved to be a reliable indicator, showing strong associations with ileal SES-CD scores, with a cutoff value of 3 effectively identifying active/severe cases of Crohn’s disease.
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High-definition (HD) endoscopy is recommended in surveillance colonoscopy for detecting dysplasia in patients with ulcerative colitis (UC). Dye-spray chromoendoscopy (DCE) and narrow-band imaging (NBI) are often used as adjunctive techniques of white-light endoscopy (WLE) in real-world practice. However, the incremental detection ability of DCE and NBI added to HD-WLE for dysplasia and serrated lesions has not yet been evaluated using tandem endoscopy in patients with long-standing extensive UC.

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Article Synopsis
  • The study aimed to determine the optimal timing for bowel preparation using polyethylene glycol (PEG) before small bowel capsule endoscopy (SBCE).
  • Patients were divided into three groups based on how long before the procedure they finished PEG: within 6 hours (group A), 6-12 hours (group B), and over 12 hours (group C).
  • Results showed that those in group A had significantly better small bowel visibility and less unclean segments compared to the other groups, suggesting that completing PEG ingestion within 6 hours prior to SBCE is optimal.
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Background: Several studies have suggested an association between inflammatory bowel disease (IBD) and the risk of prostate cancer development. However, these findings are inconsistent, and studies based on Asian populations are limited.

Objectives: We compared the risk of prostate cancer according to IBD status using the Korean National Health Insurance Service database.

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Therapeutic drug monitoring (TDM) is effective in optimizing the efficacy of infliximab in patients with inflammatory bowel disease (IBD). An affordable way of monitoring is in high demand. This study evaluated the analytical and clinical performances of the newly available Remsima monitor kits and compared them with the established enzyme-linked immunosorbent assay kits.

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Background: Th17 cells and their signature cytokine, interleukin-17A [IL-17], are considered as the main pathogenic factors in inflammatory bowel diseases [IBDs]. However, IL-17 neutralising antibodies, a theoretically curative medication for IBDs, paradoxically aggravated intestinal inflammation. The mechanisms by which IL-17 mediates the protective and pathological effects of IL-17 remain unclear in the intestinal epithelium.

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Background/aims: There is increasing evidence that supplementation with pre- and probiotics appears to have positive effects on irritable bowel syndrome (IBS). The aim of this study was to determine the effects of a new synbiotic formulation on gastrointestinal symptoms in elderly patients with IBS.

Methods: Sixty-seven IBS patients aged ≥60 years were randomly assigned to either a placebo group (n=34) or a synbiotic group (n=33).

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Background: The treatment goal of ulcerative colitis (UC) has changed from the control of symptoms to mucosal healing, previously evaluated mainly by endoscopy. Recently, the importance of histologic activity has emerged. Therefore, this study aimed to investigate the risk of clinical relapse according to histologic activity in UC with a Mayo endoscopic subsccore (MES) of 0 or 1.

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Background: Familial adenomatous polyposis (FAP) is an autosomal dominant hereditary cancer syndrome characterized by hundreds to thousands of colorectal adenomatous polyps. Without treatment, progression to colorectal cancer is inevitable. Most pathogenic mutations in the APC gene were nonsense or frameshift mutations; however, some previous studies reported large deletions or duplications.

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