Background and Aims: Although the incidence of inflammatory bowel disease [IBD] is increasing in Asia, data on long-term epidemiological trends are limited. We performed a 30-year longitudinal study to investigate temporal trends in the epidemiology of Crohn’s disease [CD] and ulcerative colitis [UC] in Seoul, Korea. Methods: This population-based study included 1431 IBD patients [418 CD, 1013 UC] diagnosed between 1986 and 2015 in the Songpa-Kangdong district of Seoul, Korea. Temporal trends in incidence, prevalence, and disease phenotype at diagnosis were analysed. Results: The adjusted mean annual incidence rates of CD and UC per 100 000 inhabitants increased from 0.06 (95% confidence interval [CI], 0.05–0.07) and 0.29 [95% CI, 0.27–0.31], respectively, in 1986–1990 to 2.44 [95% CI, 2.38–2.50] and 5.82 [95% CI, 5.73–5.92], respectively, in 2011–2015. Average annual percentage change in IBD incidence was 12.3% in 1986–1995, 12.3% in 1996–2005, and 3.3% in 2006–2015. The male-to-female ratio of the adjusted incidence rate was 3.3:1 for CD and 1.2:1 for UC. Perianal fistula/abscess was present in 43.3% of patients before or at CD diagnosis. At diagnosis, 54.3% of UC patients presented only with proctitis. The adjusted prevalence rate in 2015 was 31.59/100 000 [95% CI, 31.10–32.07] for CD and 76.66/100 000 [95% CI, 75.91–77.42] for UC. Conclusions: The incidence and prevalence of IBD in Korea have continued to increase over the past three decades. Korean patients have distinct demographic and phenotypic characteristics, including a male predominance and high frequency of perianal fistula/abscess in CD and high proportion of proctitis in UC.

Background Visual inspection, lesion detection, and differentiation between malignant and benign features are key aspects of an endoscopist’s role. The use of machine learning for the recognition and differentiation of images has been increasingly adopted in clinical practice. This study aimed to establish convolutional neural network (CNN) models to automatically classify gastric neoplasms based on endoscopic images. Methods Endoscopic white-light images of pathologically confirmed gastric lesions were collected and classified into five categories: advanced gastric cancer, early gastric cancer, high grade dysplasia, low grade dysplasia, and non-neoplasm. Three pretrained CNN models were fine-tuned using a training dataset. The classifying performance of the models was evaluated using a test dataset and a prospective validation dataset. Results A total of 5017 images were collected from 1269 patients, among which 812 images from 212 patients were used as the test dataset. An additional 200 images from 200 patients were collected and used for prospective validation. For the five-category classification, the weighted average accuracy of the Inception-Resnet-v2 model reached 84.6 %. The mean area under the curve (AUC) of the model for differentiating gastric cancer and neoplasm was 0.877 and 0.927, respectively. In prospective validation, the Inception-Resnet-v2 model showed lower performance compared with the endoscopist with the best performance (five-category accuracy 76.4 % vs. 87.6 %; cancer 76.0 % vs. 97.5 %; neoplasm 73.5 % vs. 96.5 %; P < 0.001). However, there was no statistical difference between the Inception-Resnet-v2 model and the endoscopist with the worst performance in the differentiation of gastric cancer (accuracy 76.0 % vs. 82.0 %) and neoplasm (AUC 0.776 vs. 0.865). Conclusion The evaluated deep-learning models have the potential for clinical application in classifying gastric cancer or neoplasm on endoscopic white-light images.

Objective: The association between proton pump inhibitor (PPI) use and gastric cancer related to Helicobacter pylori eradication has not been fully investigated in geographical regions with high risk of gastric cancer. We aimed to evaluate the association between PPIs and gastric cancer in Korea. Design: This study analysed the original and common data model versions of the Korean National Health Insurance Service database from 2002 to 2013. We compared the incidence rates of gastric cancer after 1-year drug exposure, between new users of PPIs and other drugs excluding PPIs, by Cox proportional hazards model. We also analysed the incidence of gastric cancer among PPI users after H. pylori eradication. Results: The analysis included 11 741 patients in matched PPI and non-PPI cohorts after large-scale propensity score matching. During a median follow-up of 4.3 years, PPI use was associated with a 2.37-fold increased incidence of gastric cancer (PPI≥30 days vs non-PPI; 118/51 813 person-years vs 40/49 729 person-years; HR 2.37, 95% CI 1.56 to 3.68, p=0.001). The incidence rates of gastric cancer showed an increasing trend parallel to the duration of PPI use. In H. pylori -eradicated subjects, the incidence of gastric cancer was significantly associated with PPI use over 180 days compared with the non-PPI group (PPI≥180 days vs non-PPI; 30/12 470 person-years vs 9/7814 person-years; HR 2.22, 95% CI 1.05 to 4.67, p=0.036). Conclusion: PPI use was associated with gastric cancer, regardless of H. pylori eradication status. Long-term PPIs should be used with caution in high-risk regions for gastric cancer.

AIM: To determine the cutoff values and to compare the diagnostic role of alpha-fetoprotein (AFP) and prothrombin induced by vitamin K absence-II (PIVKA-II) in chronic hepatitis B (CHB). METHODS: A total of 1255 patients with CHB, including 157 patients with hepatocellular carcinoma (HCC), 879 with non-cirrhotic CHB and 219 with cirrhosis without HCC, were retrospectively enrolled. The areas under the receiver operating characteristic (AUROC) curves of PIVKA-II, AFP and their combination were calculated and compared. RESULTS: The optimal cutoff values for PIVKA-II and AFP were 40 mAU/mL and 10 ng/mL, respectively, for the differentiation of HCC from nonmalignant CHB. The sensitivity and specificity were 73.9% and 89.7%, respectively, for PIVKA-II and 67.5% and 90.3% for AFP, respectively. The AUROC curves of both PIVKA-II and AFP were not significantly different (0.854 vs 0.853, P = 0.965) for the differentiation of HCC from nonmalignant CHB, whereas the AUROC of PIVKA-II was significantly better than that of AFP in patients with cirrhosis (0.870 vs 0.812, P = 0.042). When PIVKA-II and AFP were combined, the diagnostic power improved significantly compared to either AFP or PIVKA-II alone for the differentiation of HCC from nonmalignant CHB (P < 0.05), especially when cirrhosis was present (P < 0.05). CONCLUSION: Serum PIVKA-II might be a better tumor marker than AFP, and its combination with AFP may enhance the early detection of HCC in patients with CHB.

Objective No population-based study has evaluated the natural course of UC over three decades in non-Caucasians. We aimed to assess the long-term natural course of Korean patients with UC in a population-based cohort. Design This Korean population-based, Songpa-Kangdong IBD cohort included all patients (n=1013) newly diagnosed with UC during 1986–2015. Disease outcomes and their predictors were evaluated. Results During the median follow-up of 105 months, the overall use of systemic corticosteroids, thiopurines and antitumour necrosis factor (anti-TNF) agents was 40.8%, 13.9% and 6.5%, respectively. Over time, the cumulative risk of commencing corticosteroids decreased, whereas that of commencing thiopurines and anti-TNF agents increased. During follow-up, 28.7% of 778 patients with proctitis or left-sided colitis at diagnosis experienced proximal disease extension. A total of 28 patients (2.8%) underwent colectomy, demonstrating cumulative risks of colectomy at 1, 5, 10, 20 and 30 years after diagnosis of 1.0%, 1.9%, 2.2%, 5.1% and 6.4%, respectively. Multivariate Cox regression analysis revealed that extensive colitis at diagnosis (HR 8.249, 95% CI 2.394 to 28.430), ever use of corticosteroids (HR 6.437, 95% CI 1.440 to 28.773) and diagnosis in the anti-TNF era (HR 0.224, 95% CI 0.057 to 0.886) were independent predictors of colectomy. The standardised mortality ratio in patients with UC was 0.725 (95% CI 0.508 to 1.004). Conclusion Korean patients with UC may have a better clinical course than Western patients, as indicated by a lower colectomy rate. The overall colectomy rate has continued to decrease over the past three decades.