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Background Confusion between high and low confidence decisions in optical diagnosis hinders the implementation of real-time optical diagnosis in clinical practice. We evaluated the effect of a 3-second rule (decision time limited to 3 seconds for a high confidence assignment) in expert and nonexpert endoscopists. Methods This single-center prospective study included eight board-certified gastroenterologists. A 2-month baseline phase used standard real-time optical diagnosis for colorectal polyps Results Real-time optical diagnosis was performed on 1793 patients with 3694 polyps. There was significant improvement in high confidence accuracy between baseline and intervention phases in the nonexpert group (79.2 % vs. 86.3 %; P = 0.01) but not in the expert group (85.3 % vs. 87.5 %; P = 0.53). Using the 3-second rule improved the overall performance of PIVI and SODA in both groups. Conclusions The 3-second rule was effective in improving real-time optical diagnosis performance, especially in nonexperts.

To prevent colorectal cancer, high-quality colonoscopy is advocated, undertaken by endoscopists with high adenoma detection rates (ADRs). Despite reports that various factors may impact ADRs, the significance of such factors is still unclear. The analysis was aimed at quality-oriented interventions for boosting ADRs. Study enrollees were adults subjected to screening colonoscopy between September 2013 and August 2016 at the Gangnam Center of Seoul National University Hospital Healthcare System. The investigation entailed six periods (P1–6) of 6 months each, during which serial multidirectional quality improvement efforts were instituted. In particular, we sought to further educate endoscopists, provide feedback on individual ADRs, and introduce a split-dose regimen, gauging results via the Boston Bowel Preparation Score. Changes in polyp detection rates (PDRs) and ADRs were then analyzed. A total of 13,430 colonoscopies were undertaken by 15 experienced endoscopists. Overall, the ADR increased from 45.6% (P1) to 48.2% (P6, p

Purpose Although genome-wide association studies (GWASs) represent the most powerful approach for identifying genes that influence asthma, to date, no studies have established genetic susceptibility to asthma in the Korean population. This study aimed to identify genetic variants associated with adult Korean asthmatics and compare them with the significant single nucleotide polymorphisms (SNPs) of UK asthmatics from the UK Biobank. Methods Patients were defined as having asthma if they were diagnosed by a doctor or taking medications for asthma. Controls were defined as individuals without asthma or chronic obstructive pulmonary disease. We performed quality control, genotype imputation, GWAS, and PrediXcan analyses. In the GWAS, a P value of < 5 × 10−8 was considered significant. We compared significant SNPs between Korean and UK patients with asthma. Results A total of 1,386 asthmatic patients and 5,205 controls were analyzed. The SNP rs1770, located near the human leukocyte antigen (HLA)-DQB1, was the most significant SNP (P = 4.5 × 10−10). In comparison with 24 SNPs in a GWAS of UK asthmatics, six SNPs were significant with the same odds ratio (OR) direction, including signals related to type 2 inflammation (e.g., IL1RL1, TSLP, and GATA3) and mucus plugging (e.g., MUC5AC). HLA-DQA1 showed an opposite OR direction. The HLA-DQB1 gene demonstrated significantly imputed mRNA expression in the lung tissue and whole blood. Conclusions The SNP rs1770 of HLA-DQB1 was the most significant in Korean asthmatics. Similarities and discrepancies were found in the genetic variants between Korean and UK asthmatics. GWAS of Korean asthmatics should be replicated and compared with those of GWAS of other ethnicities.

Objectives Many interventions have been attempted to improve adenoma detection rate (ADR) and sessile serrated lesion detection rate (SDR), and one of these interventions is educational training to recognize polyp characteristics. This study aimed to investigate the change in polyp detection rates of endoscopists before and after comprehensive training through the Gangnam-Real Time Optical Diagnosis (Gangnam-READI) program. Methods Fifteen gastroenterologists participated in a 1-year comprehensive training program that consisted of ex vivo and in vivo training that encompasses knowledge and skills in endoscopic characterization of colonic polyps using the Workgroup serrAted polypS and Polyposis (WASP) classification. We evaluated the impact of the training program by comparing the overall and individual ADR and SDR 6 months before and after the training. Results Overall, 18,280 polyps (9337 adenomas and 855 sessile serrated lesion) were collected. The optical diagnosis training had no significant impact on the difference in ADR after training compared to before training (47.7% vs. 46.5%, P = 0.608). A tendency for a decrease in ADR variance was noted among the endoscopists after training (74.9 vs. 32.7, P = 0.121). The overall pre-training period SDR was 4.5% and showed a statistically significant increase to 5.6%, 8.0%, and 7.1% in the first and second half of the training period, and post-training period, respectively (P = 0.003). The optical diagnosis training did not decrease variance in SDR (8.9 vs. 8.8, P = 0.985). Conclusion Comprehensive optical diagnosis training with WASP classification has a significant impact on increasing the overall SDR of expert endoscopists.

Smoking is a major risk factor for chronic obstructive pulmonary disease (COPD); however, more than 25% of COPD patients are non-smokers, and gene-by-smoking interactions are expected to affect COPD onset. We aimed to identify the common genetic variants interacting with pack-years of smoking on FEV1/FVC ratios in individuals with normal lung function. A genome-wide interaction study (GWIS) on FEV1/FVC was performed for individuals with FEV1/FVC ratio ≥ 70 in the Korea Associated Resource cohort data, and significant SNPs were validated using data from two other Korean cohorts. The GWIS revealed that rs10947231 and rs8192575 met genome-wide significant levels; For $${\text{H}}_{0} :\beta_{SNP} = \beta_{SNP*pack - years} = 0{\text{ vs H}}_{1} : not {\text{H}}_{0} ,$$ H 0 : β SNP = β S N P ∗ p a c k - y e a r s = 0 vs H 1 : n o t H 0 , the likelihood ratio (LR) test was conducted, and its P values, PLR, for rs10947231 and rs8192575 were 2.23 × 10–12 and 1.18 × 10–8, respectively. Interaction between rs8192575 and smoking is significantly replicated with two additional data (PINT = 0.0454, 0.0131). Expression quantitative trait loci, topologically associated domains, and PrediXcan analyses revealed that rs8192575 is significantly associated with AGER expression. SNPs on the 6p21 region are associated with FEV1/FVC, and the effect of smoking on FEV1/FVC differs among the associated genotypes.

Osteoporosis is hard to detect before it manifests symptoms and complications. In this study, we evaluated machine learning models for identifying individuals with abnormal bone mineral density (BMD) through an analysis of spine X-ray features extracted by deep learning to alert high-risk osteoporosis populations.We retrospectively used data obtained from health check-ups including spine X-ray and dual-energy X-ray absorptiometry (DXA). Consecutively, we selected people with normal and abnormal bone mineral density. From the regions of interest of X-ray images, deep convolutional networks were used to generate image features. We designed prediction models for abnormal BMD using the image features trained by machine learning classification algorithms. The performances of each model were evaluated.From 334 participants, 170 images of abnormal (T scores- 1.0 standard deviations (SD)) and 164 of normal BMD (T scores= - 1.0 SD) were used for analysis. We found that a combination of feature extraction by VGGnet and classification by random forest based on the maximum balanced classification rate (BCR) yielded the best performance in terms of the area under the curve (AUC) (0.74), accuracy (0.71), sensitivity (0.81), specificity (0.60), BCR (0.70), and F1-score (0.73).In this study, we explored various machine learning algorithms for the prediction of BMD using simple spine X-ray image features extracted by three deep learning algorithms. We identified the combination for the best performance in predicting high-risk populations with abnormal BMD.

A relationship between lung function and sarcopenia has been suggested. This study aimed to evaluate the association between lung function and abdominal skeletal muscle mass, as measured by computed tomography (CT). The clinical records of 1907 subjects (1406 males, mean age 53.1 &plusmn, 9.2 years), who underwent routine health check-ups, including spirometry and abdominal CT, were retrospectively reviewed. The CT-measured skeletal muscle index (SMICT, cm2/(kg/m2) was defined as the skeletal muscle area of the third lumbar vertebrae (L3) level that is normalized by the body mass index. The mean values of forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) gradually increased as the SMICT quartiles increased (all p for trend &lt, 0.05). The proportions of subjects with less than 80% of the predicted FVC (%) and predicted FEV1 (%) significantly decreased as the SMICT quartiles increased (all p for trend &lt, 0.05). The &beta, regression coefficients for FVC and FEV1 significantly increased as the SMICT quartiles increased after adjusting for other confounding variables (p for trend &lt, 0.05). This study showed that abdominal muscle mass, which was precisely measured by CT, independently affected lung function proportionally after adjusting for confounding factors in relatively healthy adults.

Background/Aims: A percutaneous gastrostomy can be placed either endoscopically (percutaneous endoscopic gastrostomy, PEG) or radiologically (radiologically-inserted gastrostomy, RIG). However, there is no consistent evidence of the safety and efficacy of PEG compared to RIG. Recently, 30-day mortality has become considered as the most important surrogate index for evaluating the safety and efficacy of percutaneous gastrostomy. The aim of this meta-analysis was to compare the 30- day mortality rates between PEG and RIG. Methods: Major electronic databases (MEDLINE, Embase, Scopus, and Cochrane library) were queried for comparative studies on the two insertion techniques of gastrostomy among adults with swallowing disturbance. The primary outcome was the 30-day mortality rate after gastrostomy insertion. Forest and funnel plots were generated for outcomes using STATA version 14.0. Results: Fifteen studies (n=2,183) met the inclusion criteria. PEG was associated with a lower risk of 30-day mortality after tube placement compared with RIG (odds ratio, 0.60; 95% confidence interval [CI], 0.38-0.94; P =0.026). The pooled prevalence of 30-day mortality of PEG was 5.5% (95% CI, 4.0%-6.9%) and that of RIG was 10.5% (95% CI, 6.8%-14.3%). No publication bias was noted. Conclusions: The present meta-analysis demonstrated that PEG is associated with a lower probability of 30-day mortality compared to RIG, suggesting that PEG should be considered as the first choice for long-term enteral tube feeding. Further prospective randomized studies are needed to evaluate and compare the safety of these two different methods of gastrostomy. (Intest Res 2016;14:333-342)

Narrow-band imaging (NBI) can be used to determine whether colorectal polyps are adenomatous or hyperplastic. We investigated whether an artificial intelligence (AI) system can increase the accuracy of characterizations of polyps by endoscopists of different skill levels.We developed convolutional neural networks (CNNs) for evaluation of diminutive colorectal polyps, based on efficient neural architecture searches via parameter sharing with augmentation using NBIs of diminutive (≤5 mm) polyps, collected from October 2015 through October 2017 at the Seoul National University Hospital, Healthcare System Gangnam Center (training set). We trained the CNN using images from 1100 adenomatous polyps and 1050 hyperplastic polyps from 1379 patients. We then tested the system using 300 images of 180 adenomatous polyps and 120 hyperplastic polyps, obtained from January 2018 to May 2019. We compared the accuracy of 22 endoscopists of different skill levels (7 novices, 4 experts, and 11 NBI-trained experts) vs the CNN in evaluation of images (adenomatous vs hyperplastic) from 180 adenomatous and 120 hyperplastic polyps. The endoscopists then evaluated the polyp images with knowledge of the CNN-processed results. We conducted mixed-effect logistic and linear regression analyses to determine the effects of AI assistance on the accuracy of analysis of diminutive colorectal polyps by endoscopists (primary outcome).The CNN distinguished adenomatous vs hyperplastic diminutive polyps with 86.7% accuracy, based on histologic analysis as the reference standard. Endoscopists distinguished adenomatous vs hyperplastic diminutive polyps with 82.5% overall accuracy (novices, 73.8% accuracy; experts, 83.8% accuracy; and NBI-trained experts, 87.6% accuracy). With knowledge of the CNN-processed results, the overall accuracy of the endoscopists increased to 88.5% (P.05). With knowledge of the CNN-processed results, the accuracy of novice endoscopists increased to 85.6% (P.05). The CNN-processed results significantly reduced endoscopist time of diagnosis (from 3.92 to 3.37 seconds per polyp, P = .042).We developed a CNN that significantly increases the accuracy of evaluation of diminutive colorectal polyps (as adenomatous vs hyperplastic) and reduces the time of diagnosis by endoscopists. This AI assistance system significantly increased the accuracy of analysis by novice endoscopists, who achieved near-expert levels of accuracy without extra training. The CNN assistance system can reduce the skill-level dependence of endoscopists and costs.

Background & Aims The optimal training method for endoscopic characterization of colorectal polyps using narrow-band imaging is uncertain, and sessile serrated lesions (SSLs) optical diagnosis data are lacking. We aimed to evaluate a comprehensive training program for real-time optical diagnosis of colorectal polyps, including SSLs. Methods We performed a single-institution prospective study of 15 endoscopists trained with the Workgroup Serrated Polyps and Polyposis classification system. After the first phase of in vivo optical diagnosis, their performances were evaluated. After re-education for insufficient competency, they began the second phase. The learning curves and performance on 2 preservation and incorporation of valuable endoscopic innovations benchmarks were assessed. Results A total of 7294 polyps, including 486 SSLs, were diagnosed in real-time. The overall accuracy improved from 73.5% in the first phase to 77.1% in the second. The accuracy with high confidence was 79.4% and 85.1% in the first and second phases, respectively. In the first and second phases, the negative predictive values for diminutive neoplastic polyps were 82.1% and 92.5%, respectively, and concordances of the surveillance intervals were 80.7% and 89.7%, respectively. Eight endoscopists achieved the preservation and incorporation of valuable endoscopic innovations benchmarks after the second phase compared with none after the first. In contrast, the high confidence rate decreased from 74.6% to 70.2% as training progressed. Conclusion A comprehensive training program for real-time optical diagnosis significantly improved performance and reduced individual variability in less-experienced endoscopists. ClinicalTrials.gov no: NCT 02516748.

Background: The neutrophil–lymphocyte ratio (NLR) is a valuable prognostic or predictive biomarker in various diseases, but the genetic factors that underlie the NLR have not been studied. We attempted to investigate polymorphisms related to NLR phenotype and analyze their ability to predict metabolic risks. Methods: A genome-wide association study was performed with log-transformed NLR using an Affymetrix Axiom™ KORV1.1-96 Array. Regression models for metabolic risk status were designed using the identified significant single-nucleotide polymorphisms (SNPs). Results: We identified four SNPs near the TMEM116, NAA25, and PTPN11 genes that were associated with the NLR. The top SNP associated with the log-transformed NLR was rs76181728 in TMEM116. A case–control study was performed to analyze the metabolic risks associated with each SNP after adjusting for age, sex, and body mass index (BMI). Three SNPs displayed significant odds ratios (ORs) for increased blood pressure and increased waist circumference. In the regression model for metabolic syndrome, rs76181728 showed a significant association (OR = 1.465, 95% confidence interval (CI) = 1.091–1.969, P = 0.011) after adjustment for the NLR phenotype. Conclusions: We identified four novel SNPs that are associated with the NLR in healthy Koreans. SNPs in relevant genes might therefore serve as biomarkers for metabolic risks.

Cigarette smoke exposure is a major risk factor in chronic obstructive pulmonary disease (COPD) and its interactions with genetic variants could affect lung function. However, few gene-smoking interactions have been reported. In this report, we evaluated the effects of gene-smoking interactions on lung function using Korea Associated Resource (KARE) data with the spirometric variables—forced expiratory volume in 1 s (FEV1). We found that variations in FEV1 were different among smoking status. Thus, we considered a linear mixed model for association analysis under heteroscedasticity according to smoking status. We found a previously identified locus near SOX9 on chromosome 17 to be the most significant based on a joint test of the main and interaction effects of smoking. Smoking interactions were replicated with Gene-Environment of Interaction and phenotype (GENIE), Multi-Ethnic Study of Atherosclerosis-Lung (MESA-Lung), and COPDGene studies. We found that individuals with minor alleles, rs17765644, rs17178251, rs11870732, and rs4793541, tended to have lower FEV1 values, and lung function decreased much faster with age for smokers. There have been very few reports to replicate a common variant gene-smoking interaction, and our results revealed that statistical models for gene-smoking interaction analyses should be carefully selected.

This study was planned to evaluate the incidence and risk factors of osteoporosis and fracture after gastrectomy for stomach cancer using a nationwide claims database in South Korea. Data from 41,512 patients (50–79 years) who underwent gastrectomy for stomach cancer from 2008 to 2010 with at least 5 years of follow-up were obtained from the Health Insurance Review and Assessment Service database. Patients diagnosed with osteoporosis and prescribed bisphosphonate or raloxifene or who experienced osteoporotic fractures after gastrectomy were operationally defined as osteoporosis. Osteoporotic fracture was defined as a fracture at common osteoporotic fracture sites (spine, pelvis, hip, forearm, or rib). In total, 37,076 patients were included in the final analysis. The incidences of postgastrectomy osteoporosis and osteoporotic fractures were 41.9 and 27.6 cases per 1000 person-years, respectively. Multivariate analysis showed that older age (hazard ratio [HR] 1.88; 95% confidence interval [CI] 1.79–1.96), female gender (HR 2.46; 2.35–2.58), total gastrectomy (HR 1.10; 1.04–1.16), and diabetes (HR 1.16; 1.11–1.22) were significantly associated with osteoporosis and that older age (HR 1.90; 95% CI 1.80–2.01), female gender (HR 1.50; 1.41–1.58), total gastrectomy (HR 1.17; 1.10–1.25), chemotherapy (HR 1.06; 1.00–1.12), and diabetes (HR 1.26; 1.19–1.33) were significantly associated with fractures. Osteoporotic fractures occurred a median 3.1 years after gastrectomy. Among the 5175 fracture patients, 780 (15.1%) experienced multisite fractures, mostly in the elderly and chemotherapy groups. The osteoporosis and osteoporotic fracture incidences are high in patients within a relatively short timeframe after gastrectomy for stomach cancer. Systematic management of osteoporosis is necessary after this surgery.

Colorectal adenoma and coronary atherosclerosis have similar risk factors. The aim of this study was to investigate the association between colorectal adenoma and coronary artery calcification (CAC), which is used as a surrogate marker for coronary atherosclerosis.This is a cross-sectional study of 398 Koreans (290 males, mean age of 56.8 ± 8.1 years) who underwent CAC scoring by multi-slice computed tomography and colonoscopy on the same day as the screening examination. The CAC scores were divided into the following three categories according to severity: absent (CAC score = 0), mild (0CAC score ≤ 100), and moderate-to-severe CAC (CAC score100).Colorectal adenoma was detected in 149 (37.4%) subjects and was significantly associated with a CAC score of0 (OR = 1.66, 95% CI = 1.05-2.64, P = 0.032), including both mild (OR = 1.80, 95% CI = 1.06-3.03, P = 0.029) and moderate-to-severe CAC (OR = 1.95, 95% CI = 1.05-3.63, P = 0.035), in multivariate analysis after adjusting for age, gender and other risk factors. The proportion of subjects with colorectal adenoma and advanced adenoma progressively increased with increasing CAC score (colorectal adenoma 28.9%-54.1%, P for trend0.001; advanced adenoma 7.0%-16.4%, P for trend = 0.026).Colorectal adenoma is related to coronary artery calcification independent of traditional risk factors for asymptomatic Koreans. The prevalence of advanced adenoma is more common in individuals with severe coronary atherosclerosis.

The aim of this study was to prospectively assess the effects of the order of colonoscopic procedures and other possible factors on the adenoma detection rate (ADR).There have been conflicting studies regarding the timing or order of a colonoscopy and its ability to detect adenomas.Between March 2011 and July 2011, consecutive colonoscopies were prospectively performed by 7 board-certified staff endoscopists at the Seoul National University Hospital Healthcare System Gangnam Center. The primary outcome was the overall ADR according to the procedure order of the colonoscopies, and the secondary outcome was the identification of other possible factors influencing the ADR.A total of 1908 colonoscopies were analyzed. The detection rate was 56.5% for all polyps and 37.3% for adenomas. The ADR increased as the performance order of the colonoscopy increased and was highest for the third procedure (43.4%). However, the ADR of the remaining procedures, including later procedures, was similar throughout the workday. In the multivariable analysis, the ADR was significantly associated with older age, male sex, high body mass index, personal history of colorectal polyps, long withdrawal time, and an experienced endoscopist. However, the colonoscopy procedure order was not significantly associated with the ADR.The ADR was stable according to the procedure order for the later procedures of the workday in a setting of moderate daily procedure volumes. The withdrawal time and experience level of the endoscopist were more important than the procedure order in detecting adenomas by colonoscopy.

There are limited data on the performance of narrow band imaging (NBI) and Fujinon intelligent color enhancement (FICE) for differentiating polyp histologies.The aim of this study was to compare the diagnostic performances of NBI and FICE in differentiating neoplastic from non-neoplastic colorectal polyps10 mm during screening colonoscopy.A total of 955 average-risk adults undergoing screening colonoscopies were randomly allocated to NBI or FICE groups. Four board-certified staff endoscopists without prior experience using NBI or FICE participated. The main outcomes of this study were overall accuracy, sensitivity, and specificity of FICE and NBI in identifying neoplastic polyps.There was no significant difference in the number of subjects with adenoma between the NBI (143/475, 30.1 %) and FICE groups (139/480, 29.0 %) (after excluding adenoma ≥1 cm) (P0.05). The overall accuracy of NBI was 81.0 %, compared with 81.4 % for FICE (P = 0.867). The overall sensitivity and specificity of NBI and FICE were 84.6 and 78.0 % (P = 0.054); 75.1 and 86.5 % (P = 0.009), respectively. For polyps measuring ≤5 mm, the accuracy was 79.4 % for NBI and 80.1 % for FICE (P = 0.835; sensitivity 81.9 vs. 74.5 %, P = 0.064; specificity 75.7 vs. 88.4 %, P = 0.006).The overall accuracy of NBI and FICE was similar for differentiating small polyp histologies during screening colonoscopy. However, better results should be achieved before using NBI or FICE as real-time optical biopsy of colorectal polyps in screening colonoscopy.

We conducted this study to explore the extent of occult helminth infection identified by fecal parasitological examinations or organ-specific examinations such as colonoscopy and abdominal ultrasonography (US) during health checkups. We analyzed 197,422 fecal samples from 99,451 subjects who received health checkups at a single center over 10 years. We found that 3,472 (1.8%) samples from 3,342 (3.4%) subjects tested positive for parasitic ova, including clonorchiasis, metagonimiasis, trichuriasis, ascariasis, trichostrongylosis, taeniasis, and enterobiasis. The detection rate for clonorchiasis was higher in those who were taking their first examination than in those who had been examined previously. The detection rate for clonorchiasis decreased gradually over the 10 years. Only 2.5% of the patients with clonorchiasis showed US or computed tomography (CT) images that were compatible with the disease. Clonorchiasis patients who had abdominal US or CT images that suggested clonorchiasis were older and had lower body mass indices and higher eosinophil counts than did those whose US or CT images did not suggest the disease. We observed worms in 9% of the patients with trichuriasis who had received a colonoscopy. Colonoscopy also uncovered adult worms in 0.03% of subjects who were not identified as having Trichuris trichiura ova in their fecal helminth examinations. In summary, our study shows that occult helminth infection is fairly frequently identified by a variety of methods during health checkups, which suggests that doctors need to make greater effort to identify and treat occult helminth infections in Korea.

Serum carcinoembryonic antigen (CEA) is a well-known tumor marker for colorectal adenocarcinoma. However, CEA levels can be influenced by various nonmalignant conditions. A retrospective, cross-sectional study was performed including 18,131 healthy nonsmokers who underwent health check-ups with evaluation of the serum CEA level. In the training set, multivariate analysis revealed that the log-transformed CEA level had positive relationships with age (regression coefficient (r) = 0.005, P<0.001), white blood cell (WBC) count (r=0.007, P=0.016), hemoglobin (HB, r=0.016, P<0.001), aspartate aminotransferase (AST, r=0.002, P=0.005), creatinine (r=0.076, P=0.038), and glycosylated hemoglobin (HbA1c, r=0.052, P<0.001); body mass index (BMI, r=−0.007, P<0.001) showed a negative correlation. The results for age, BMI, WBC count, HB, AST, and HbA1c were validated in the test set. We were able to construct the following model to predict the log-transformed CEA level: log (CEA + 0.51) = −0.204 − 0.051 (gender) + 0.005 (age) − 0.006 (BMI) + 0.008 (WBC count) + 0.016 (HB) + 0.002 (AST) + 0.062 (creatinine) + 0.054 (HbA1c). For colorectal cancer prediction, the model with the observed CEA and adjusted CEA levels had significantly high predictive power (AUC 0.756, P<0.001) than the model only including the observed CEA level (AUC 0.693, P<0.001). Factors influencing serum CEA levels should be adjusted before clinical interpretation to increase the predictive value of CEA.

AIM To evaluate the effectiveness and tolerability of a split-dose 2 L polyethylene glycol (PEG)/ascorbic acid (AA) regimen for healthy examinees who visited for comprehensive medical check-up in the early morning. METHODS From February 2015 to March 2015, examinees of average risk who were scheduled for a colonoscopy in the morning were retrospectively enrolled. RESULTS The 189 examinees were divided into split-dose and non-split-dose groups. The adequacy of bowel preparation for the split-dose group vs the non-split-dose group was 96.8% vs 85.2%, respectively, P < 0.001, and the compliance of the last meal restriction was 74.6% vs 58.2%, respectively, P < 0.001. The sleep disturbance (P < 0.001) was more prevalent in the split-dose group, however the willingness to repeat the same preparation method (P = 0.243) was not different in both groups. The split-dose regimen was the most important factor influencing adequate bowel preparation in multivariate analysis (HR = 10.89, 95%CI: 6.53-18.17, P < 0.001). CONCLUSION A split-dose regimen of 2 L PEG/AA for an early morning colonoscopy was more effective and showed better compliance for diet restriction without any difference in satisfaction and discomfort. Introducing a split-dose regimen of 2 L PEG/AA to morning colonoscopy examinees is effective and tolerable in a comprehensive medical check-up setting.

Previous studies suggested that polymorphisms of proinflammatory cytokine genes are important host genetic factors in Helicobacter pylori infection. The present study evaluated whether IL-8-251 polymorphism affected H. pylori eradication rate and to investigate the effect of H. pylori eradication on angiogenesis and the inflammatory process according to the IL-8-251 polymorphism. A total of 250 H. pylori-positive patients treated by endoscopic resection of the gastric neoplasm were classified into 3 groups (134 H. pylori-eradicated group, 19 H. pylori-eradication failure group, and 97 H. pylori-infected group). H. pylori status, histology, and angiogenic factor levels were evaluated at baseline, 6 months, and 18 months. H. pylori eradication rate was 92.9% in AA genotype, 85.7% in AT genotype and 88.4% in TT genotype (P value = 0.731). Elevated IL-8 and matrix metalloproteinase-9 concentrations in H. pylori-infected gastric mucosa were reversible by successful eradication of H. pylori, independent of the IL-8-251 polymorphism. It is suggested that elevated IL-8 and MMP-9 concentrations in H. pylori-infected gastric mucosa are altered significantly after successful eradication and these conditions continue for 18 months. However, IL-8-251 polymorphism does not affect H. pylori eradication rate and the sequential changes of related angiogenic factors after H. pylori eradication in Koreans.

A relationship between nonalcoholic fatty liver disease (NAFLD) and sarcopenia has been suggested. The aim of this study was to evaluate the association between NAFLD and skeletal muscle mass measured by computed tomography (CT). The clinical records of individuals visiting our center for a routine health check-up who underwent abdominal ultrasonography and abdominal CT scanning were retrospectively reviewed. Sarcopenia was diagnosed according to body mass index (BMI)-adjusted skeletal muscle mass, which was measured by CT (CT-measured skeletal muscle index (SMICT)). Of the 1828 subjects (1121 males, mean age 54.9 &plusmn, 9.5 years), 487 (26.6%) were obese (BMI &ge, 25 kg/m2), and 454 (24.8%) had low muscle mass. Sarcopenic subjects had a significantly higher prevalence of NAFLD than nonsarcopenic subjects, regardless of obesity (35.9% vs. 26.8%, p = 0.004 in the nonobese group, 76.6% vs. 63.0%, p = 0.003 in the obese group). Sarcopenia was significantly associated with the risk of NAFLD (adjusted odds ratio (OR) (95% confidence interval (CI)), 1.51 (1.15&ndash, 1.99)), and the risk of NAFLD increased with increasing severity of sarcopenia (adjusted OR (95% CI), 1.45 (1.09&ndash, 1.92) vs. 2.51 (1.16&ndash, 5.56), mild vs. severe sarcopenia, respectively). When the risk of NAFLD was analyzed according to the SMICT quartiles, the adjusted OR and 95% CI for the lowest muscle mass quartile compared to the highest were 1.78 (1.17&ndash, 2.72) in males and 2.39 (1.13&ndash, 5.37) in females. Low skeletal muscle mass, which was precisely measured by CT, is independently associated with NAFLD, suggesting that sarcopenia is a risk factor for NAFLD.

Obesity, particularly abdominal obesity, might be related to decreased lung function. We aimed to investigate whether obesity indices are associated with forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) in asymptomatic non-smokers through a longitudinal cohort study. The clinical records of 1,145 subjects (428 males, mean age 52.3 years) who underwent a comprehensive health evaluation, including spirometry and abdominal fat computed tomography, at least twice between 2007 and 2014 were retrospectively reviewed and analysed. The mean follow-up period was 1,105 days (over 3.0 years). The baseline total adipose tissue (TAT) and visceral adipose tissue (VAT) were inversely associated with both FEV1 and FVC (P < 0.05). The longitudinal study found that increasing TAT and VAT were significantly related to decreasing FEV1 and FVC, whereas decreasing TAT and VAT were related to increasing FEV1 and FVC in both males and females (P < 0.05). The strength and consistency of these associations were clearer in males than in females. However, no significant relationship was found between changes in subcutaneous adipose tissue and changes in lung function. In Korean non-smokers, longitudinal changes in abdominal visceral fat were found to be inversely related to changes in lung function over a mean period of three years. These results suggest that decreasing abdominal visceral obesity could increase lung function despite ageing.

Gallbladder (GB) polyps are commonly encountered in clinical practice, and are found more frequently as the number of medical screening examinations increases. The aim of this study was to determine optimal practice guideline for surgical treatment and follow-up of GB polyps.Data from healthy subjects of Seoul National University Hospital (SNUH) Health Care System of Gangnam Center were used to investigate the true prevalence of GB polyps. We also enrolled 689 patients with GB polyps diagnosed at SNUH from May 1(st), 1988 to April 30(th), 2006.The GB polyp prevalence was 6.1% (7.1% in males and 4.8% in females). The median follow-up duration in the 689 study patients was 60 months, and 139 (20%) of them had polyps/=10 mm in size. Twenty-five of the 180 patients who underwent cholecystectomy had adenocarcinomas. The chi(2) test was used to identify which of the following were risk factors of malignancy: age, sex, symptoms, size, rate of growth, multiplicity, accompanying stones, and shape. Age (/=57 years), presence of symptoms, size (/=10 mm), and shape (sessile) were found to be statistically significant risk factors by univariate analysis. However, multivariate analysis identified only age (/=57 years) and size (/=10 mm) as independent predictors of malignancy.The present study shows that GB polyps/=10 mm in size in patients aged/=57 years are the independent factors predicting malignancy of the GB.

Background and Aim: Despite the low incidence of perforation after endoscopic procedures in the colon, the increasing use of these procedures is likely to cause a commensurate increase in such problems. This study was undertaken to determine the incidence of iatrogenic perforation of the colon, to define clinical characteristics, and to assess the management of these complications. Methods: A retrospective review of the medical records was performed for all patients with iatrogenic colon perforations after endoscopy between January 2000 and June 2007. Results: Over this 7-year study period, a total of 20,660 sigmoidoscopies, 17,102 colonoscopies, and 6,772 therapeutic procedures were performed, and 53 (0.12%) perforations were determined to be related to endoscopy. A diagnostic procedure was undertaken in 26 of these 53 perforation cases (perforation rate, 0.07%; 1 per 1,452 procedures), and a therapeutic procedure in the remaining 27 (perforation rate, 0.40%; 1 per 251 procedures). Nineteen patients (36%) were treated conservatively, and the remaining 34 (64%) required surgical management. Endoscopic clipping was performed in 9 patients, and conservative treatment was possible in 7 patients with successful closure. No procedure-related mortality occurred. Conclusions: Endoscopic repair of iatrogenic colon perforations with clips could reduce immediate operative intervention rates.

Angioimmunoblastic T-cell lymphoma (AITL) is a rare, systemic lymphoproliferative disorder that accounts for approximately 1% of all non-Hodgkin's lymphomas [1]. AITL typically presents as generalized lymphadenopathy, usually accompanied by systemic symptoms, such as, fever, malaise, and weight loss [2, 3], but primary gastrointestinal involvement is very rare [4]. In addition, it is difficult for clinicians to confirm lymphoma involving the gastrointestinal tract, based only on endoscopic findings and/or light microscopic findings [5]. We report a case of AITL that presented with chronic diarrhea and generalized weakness. The preliminary diagnosis in this case was Crohn's disease, and the final diagnosis was delayed because of the unusual presentation.

BACKGROUND AND STUDY AIMS Subepithelial tumor is a relatively common finding in upper gastrointestinal endoscopy. This study aimed to evaluate the natural course of incidentally detected small subepithelial tumors in the upper gastrointestinal tract and to analyze risk factors for increase in the size of such tumors. PATIENTS AND METHODS Medical records of 1684 patients with subepithelial tumors in the upper gastrointestinal tract incidentally detected between 2004 and 2013 were retrospectively reviewed. If serial follow-up endoscopy showed significant size increase, endoscopic or surgical resection was recommended because of possibility of malignant change. RESULTS 954 participants with subepithelial tumors underwent serial upper gastrointestinal endoscopy for a period > 6 months. Initial mean size of subepithelial tumors was 8.7 mm (range 1 - 35 mm). During a mean follow-up of 47.3 months (range 6 - 118 months), lesion size was unchanged in 920 participants (96.4 %), and in 34 participants (3.6 %) lesions had increased at least 25 % in diameter (mean increment 6.2 mm, range 2 - 15 mm). Subepithelial tumors with overlying mucosal changes (hyperemia, erosion, or ulcer) had a significantly higher risk of increasing in size (odds ratio [OR] = 3.61, 95 % confidence interval [95 %CI] 1.06 - 12.28). Growth rates (size increment per year) for enlarging lesions were significantly correlated with initial size (r = 0.44, P = 0.009). CONCLUSIONS Most incidentally detected small subepithelial tumors in the upper gastrointestinal tract showed no size change during follow-up. Thus, regular follow-up with serial endoscopy may be sufficient for small subepithelial tumors (

Background: The carcinoembryonic antigen (CEA) is widely used as a tumor marker because of its overexpression in adenocarcinomas, particularly colorectal cancer. The aim of this study was to investigate the metabolic factors including visceral obesity that are associated with serum CEA levels in non-smokers. Methods: This was a cross-sectional study of 1958 Koreans (1181 males, mean age 54.6 ± 8.7 years) who underwent serum CEA level and computed tomography-based visceral fat area assessments on the same day as a screening examination. The subjects were divided into 2 groups according to their median CEA level (1.20 ng/mL). Results: The multivariable analysis revealed that CEA was associated with age (OR=1.029, 95% CI=1.017 – 1.040, P

This study was performed to evaluate the implication of anti-H. pylori IgG positivity when CLOtest, histological test, and culture in the antrum and body are all negative, and to find out the specific disease category that is more affected by the hostile relationship of atrophic gastritis and intestinal metaplasia (IM) with H. pylori. Four hundred thirty-six patients (84 controls, 69 with duodenal ulcer, 96 with benign gastric ulcer, 43 with dysplasia, 144 with gastric cancer), who had not received any eradication therapy, were divided into three groups according to H. pylori test: CLOtest or histological H. pylori-positive group (group A; 294 cases), only anti-H. pylori IgG-positive group (group B; 62 cases), and anti-H. pylori IgG-negative group (group C; 80 cases). The grade of neutrophil and monocyte infiltration, atrophic gastritis, and IM was compared according to the updated Sydney system classification. Neutrophil and monocyte infiltrations were significantly severe in the group A. In contrast, the grade of atrophic gastritis and IM in the antrum was significantly higher in group B than the other two groups, A or C. When patients were divided according to the disease outcome in each group, the grade of IM in the body was statistically higher only in the patients with cancer or dysplasia in group B. These results suggest that anti-H. pylori IgG positivity with all negative invasive H. pylori tests represents past infection with H. pylori rather than a false negative, especially in the case of dysplasia and gastric cancer.

Various factors including age, sex, body mass index (BMI) and history of operation have been linked to the colonoscopic intubation time. The aims of this study were to identify the factors predicting cecal intubation time (CIT) and to evaluate the effect of the visceral adipose tissue (VAT) area on CIT.A total of 1386 consecutive subjects who underwent colonoscopy and abdominal CT on the same day for a health checkup at a single health care center in Korea from August to December 2011 were studied prospectively. Age, sex, BMI, height, waist circumference, history of operation, symptoms of irritable bowel syndrome, bowel preparation status, experience of colonoscopists, VAT amount on abdominal CT and time required to reach the cecum were analyzed.The mean age of the subjects was 53.0 ± 9.6 years, and 63.5% were male. The median CIT was 271 s. Univariate analyses showed that female gender, old age, shorter height, lower BMI, prior history of surgery and lower VAT were associated with longer CIT. To adjust for confounding effects of the gender, we investigated the genders separately in multivariate analysis. Older age and lower VAT were associated with prolonged CIT. However, the significance of association of VAT on prolonged CIT disappeared in women.This study demonstrates that CIT is prolonged by lower VAT area in men. This is the first study to demonstrate a direct association between VAT area and CIT.

Objective Virtual chromoendoscopy (CE) is expected to enhance adenoma yield and reduce variation in performance between colonoscopists. This study aimed to compare the efficacy of narrow band imaging (NBI), flexible spectral imaging CE (FICE) and white light (WL) colonoscopy and their impact for less experienced endoscopists. Methods We performed a randomised tandem colonoscopy trial controlling for withdrawal time and bowel preparation. Average-risk adults undergoing screening colonoscopy were enrolled and randomly assigned to first withdrawal with one of the three imaging modalities (NBI (NBI-WL group), FICE (FICE-WL group) and WL (WL-WL group)). Eight colonoscopists were categorised into expert and non-expert subgroups. Results 1650 subjects (mean age 51.4 years, 63.9% men) were included (550 in each group). Compared with WL, neither NBI nor FICE increased the mean number of adenomas detected per patient (0.37 vs 0.35 and 0.36; p=0.591) or the percentage of patients with adenoma (25.3% vs 24.5% and 23.6%; p=0.753). For all three modalities, expert subgroups had higher yields of adenomas than non-expert subgroups. Learning curves were observed only for non-expert subgroups with all three modalities. The percentage of missed adenomas did not differ between the three groups (20.8% by WL vs 22.9% by NBI and 26.0% by FICE, p=0.300) and was not affected by endoscopists’ expertise. Conclusions Neither NBI nor FICE improved adenoma detection or miss rates, with no difference in diagnostic efficacy between the two systems. Virtual CE had no additional benefits over WL for non-experts. Clinical trial registration number: KCT0000570.

AIM: To investigate the relationship between Helicobacter pylori (H. pylori) seropositivity and the presence of microalbuminuria. METHODS: Between December 2003 and February 2010, asymptomatic individuals who visited the Seoul National University Healthcare System Gangnam Center for a routine check-up and underwent tests for H. pylori immunoglobulin G antibodies and urinary albumin to creatinine ratio (UACR) were included. All study subjects completed a structured questionnaire, anthropometric measurements and laboratory tests. Anti-H. pylori immunoglobulin G was identified using an enzyme-linked immunosorbent assay kit. A random single-void urine sample, collected using a clean-catch technique, was obtained to determine the UACR. The presence of microalbuminuria was defined as a UACR from 30 to 300 μg/mg. The presence of diabetes mellitus (DM) was defined as either a fasting serum glucose level greater than or equal to 126 mg/dL or taking anti-diabetic medication. Multiple logistic regression analysis was performed to identify the risk factors. The dependent variable was microalbuminuria, and the independent variables were the other study variables. RESULTS: A total of 2716 subjects (male, 71.8%; mean age, 54.9 years) were included. Among them, 224 subjects (8.2%) had microalbuminuria and 324 subjects (11.9%) had been diagnosed with DM. Subjects with microalbuminuria had a significantly higher H. pylori seropositivity rate than subjects without microalbuminuria (60.7% vs 52.8%, P = 0.024). Multivariate analysis after adjustment for age, body mass index (BMI), waist circumference, and glucose and triglyceride levels showed that H. pylori seropositivity was significantly associated with microalbuminuria [odds ratio (OR), 1.40, 95% CI, 1.05-1.89, P = 0.024]. After the data were stratified into cohorts by glucose levels (≤ 100 mg/dL, 100 mg/dL < glucose < 126 mg/dL, and ≥ 126 mg/dL or history of DM), H. pylori seropositivity was found to be significantly associated with microalbuminuria in diabetic subjects after adjusting for age, BMI and serum creatinine level (OR, 2.21, 95% CI, 1.20-4.08, P = 0.011). In addition, the subjects were divided into five groups. Those without microalbuminuria (an UACR of < 30 μg/mg) were divided into four groups in accordance with their UACR values, and subjects with microalbuminuria comprised their own group. Notably, H. pylori seropositivity gradually increased with an increase in UACR (P = 0.001) and was highest in subjects with microalbuminuria (OR, 2.41, 95% CI, 1.14-5.11). This suggests that H. pylori seropositivity is positively associated with microalbuminuria in diabetic subjects. CONCLUSION: H. pylori seropositivity was independently associated with microalbuminuria, and the prevalence of H. pylori seropositivity was associated with the severity of UACR in diabetic subjects.

We investigated risk factors for gastric cancer (GC) and effect of annual endoscopic screening on detection and treatment modality of GC. Asymptomatic adults who underwent upper endoscopy during health checkups at Seoul National University Hospital Healthcare System Gangnam Center were enrolled. We compared clinicopathologic characteristics of GC according to screening interval (repeated vs. infrequent, annual vs. biennial). After age- and sex-matching, relative risk was computed by hazard ratio (HR) using Cox proportional regression with multivariate adjustment. Of the 58,849 subjects who received screening endoscopy, 277 (0.47%) were found to have GC. Intestinal type comprised 55.4% (102/184) followed by diffuse type (n = 65, 35.3%). Age ≥ 50 years, family history and smoking independently increased the risk of GC for both types, whereas male gender [HR = 4.81, 95% confidence interval (CI): 2.72-8.03] and intestinal metaplasia (IM) (HR = 10.87, 95% CI: 3.36-22.30) were significant predictors for intestinal type only. Proportion of early gastric cancer (EGC) was 98.6% (71/72) in annual screening group and 80.7% (46/57) in biennial screening group (p < 0.01). In the former, tumor size was smaller (1.7 ± 1.3 vs. 2.3 ± 1.8 cm; p < 0.01] and proportion of intramucosal cancer was larger (75.0 vs. 56.1%; p = 0.04). Endoscopic resection was performed more frequently in annual screening group (56.9 vs. 33.3%; p = 0.02). IM along with male gender and older age was a strong risk factor for intestinal type GC. Annual screening group improved detection of early-stage and endoscopically treatable GC suggesting that intensive screening and surveillance may be useful for high-risk subpopulations with epidemiologic risk factors or premalignant lesions such as IM.

Gastrointestinal endoscopy is imperative for acute upper gastrointestinal bleeding (AUGIB) to find bleeding focus and stop bleeding. This study was designed to assess the necessity of emergency endoscopy and determine screening criteria for the patients who presented to emergency room (ER) with after-hours AUGIB.The medical records of 383 patents with AUGIB who presented to ER at after-hours were reviewed. Patients were divided into 2 groups: emergency endoscopy (EE) group (12 hours after arrival) or delayed endoscopy (DE) group (12-24 hours after arrival). We compared the severity, hemostatic procedures, rebleeding rate, length of hospitalization and 30-day mortality between the two groups.Ninety-eight patients in EE group and 137 patients in DE group were evaluated among patients with non-variceal upper gastrointestinal bleeding. No significant differences in clinical severity, finding the bleeding focus, hemostasis, 30-day mortality, hospital stay, and rebleeding rate were observed between the two groups. Among 148 patients with variceal upper gastrointestinal bleeding, 65 patients were in EE group and 83 patients in DE group. Most clinical severity index were not different between the groups. In EE group, the rate of finding bleeding foci was lower (p=0.043), and 30-day mortality was higher than in DE group (p=0.023).Emergency endoscopy within 12 hours after arrival at after-hours do not lead to better prognosis in AUGIB.

Early gastric cancer (EGC) with undifferentiated histology has not been generally accepted as an indication for endoscopic treatment. This study was designed to evaluate the outcomes and clinicopathological factors associated with the complete resection of undifferentiated EGC using endoscopic submucosal dissection (ESD).A retrospective analysis of prospectively collected data was performed on consecutive patients who underwent ESD. Among the 456 EGCs treated using ESD at the Seoul National University Hospital, Seoul, Korea, between April 2005 and June 2008, 60 lesions (13.2%) were diagnosed as undifferentiated gastric cancer (poorly differentiated adenocarcinoma or signet ring cell carcinoma).En bloc resection was performed in all lesions without significant complications. The size discrepancy between the pretreatment endoscopy and the resected specimen was significantly higher in undifferentiated EGCs than differentiated EGCs (p = 0.002). The complete resection rate was significantly lower for undifferentiated EGC (55%) cases than differentiated EGC cases (84.1%; p0.001). Independent risk factors for incomplete resection of undifferentiated EGC included tumor size20 mm, submucosal invasion, and presence of ulceration. During a mean observation time of 16 months, no recurrence developed in any of the patients with undifferentiated EGCs thought to be completely resected by ESD.ESD might be considered an alternative treatment modality in carefully selected cases of undifferentiated EGC.

Background/Aims: Helicobacter pylori causes extragastric manifestations, including dyslipidemia and metabolic syndrome. However the effects of eradication of H. pylori infection on dyslipidemia and metabolic syndrome have shown conflicting results. We aimed to investigate the effect of eradication therapy on parameters of dyslipidemia and metabolic syndrome and prevalence of metabolic syndrome. Materials and Methods: Subjects who received eradication therapy between August 2004 and June 2010 and who underwent health checkup one year after eradication were enrolled in this study. Parameters of dyslipidemia and metabolic syndrome before and after eradication were collected and tested for significant changes. Prevalence of metabolic syndrome before eradication was also compared with that after treatment. Results: Of the 452 subjects enrolled, 324 subjects were males. In male, HDL cholesterol was significantly elevated after eradication treatment in both young (≤ 50) and old (＞50) age group. Other metabolic parameters such as waist circumference, body mass index, total cholesterol, triglyceride, LDL cholesterol, fasting glucose, systolic and diastolic blood pressure, and c-reactive protein were not significantly different after eradication in both age group. In female, triglyceride increased significantly and HDL cholesterol decreased after eradication in the old age group. But in the young age female group all the metabolic parameters showed no changes. There were no significant changes in prevalence of metabolic syndrome after eradication treatment in both genders. Conclusions: Helicobacter eradication caused elevation of HDL cholesterol in males. Eradication therapy showed no effect on prevalence of metabolic syndrome. (Korean J Helicobacter Up Gastrointest Res 2011;11: 176-184)

We thank Dr. Fatourou and Roukos for their interest and remarks in response to our article regarding endoscopic resection for undifferentiated early gastric cancer [1]. Since 1999, a national cancer screening program has recommended upper gastrointestinal endoscopy to the normal population older than 40 years for early detection of gastric cancer in Korea. The proportion of early gastric cancer indicated for endoscopic resection has increased. Although conventional endoscopic resection was limited to complete resection only for large or deep tumors confined to the mucosa without the risk of lymph node metastasis, newly developed endoscopic submucosal dissection has enabled complete resection of larger and deeper tumor without any technical barrier. With the progress of technical advances, Japan has proposed expanding the indications for endoscopic resection of early gastric cancer [2]. Although tumor of undifferentiated histology has the risk of much larger size and deeper invasion than expected, some portion of an early lesion could possibility be indicated for complete endoscopic resection as a minimally invasive treatment. In a retrospective study with postoperative pathologic review, undifferentiated early gastric cancer smaller than 2.5 cm and confined to the mucosa did not show any lymph node metastasis in a large series [3]. As expected, the complete resection rate for undifferentiated early gastric cancer was significantly lower than for differentiated histology, which explains the possibility of diffuse infiltration of tumor with undifferentiated histology and the risk of lymph node metastasis. Although endoscopic submucosal dissection has improved the complete resection of early gastric cancer more than conventional mucosal resection, expanding the indication to tumor of undifferentiated histology has the risk of incomplete resection or lymph node metastasis and should be accompanied by long-term follow-up evaluation. We think the indication for endoscopic resection of undifferentiated gastric cancer should be limited to small tumors confined to the mucosa.