Published papers

Deep learning has recently been gaining attention as a promising technology to improve the identification of lesions, and deep-learning algorithms for lesion detection have been actively developed in small-bowel capsule endoscopy (SBCE). We developed a detection algorithm for abnormal findings by deep learning (convolutional neural network) the SBCE imaging data of 30 cases with abnormal findings. To enable the detection of a wide variety of abnormal findings, the training data were balanced to include all major findings identified in SBCE (bleeding, angiodysplasia, ulceration, and neoplastic lesions). To reduce the false-positive rate, “findings that may be responsible for hemorrhage” and “findings that may require therapeutic intervention” were extracted from the images of abnormal findings and added to the training dataset. For the performance evaluation, the sensitivity and the specificity were calculated using 271 detectable findings in 35 cases. The sensitivity was calculated using 68,494 images of non-abnormal findings. The sensitivity and specificity were 93.4% and 97.8%, respectively. The average number of images detected by the algorithm as having abnormal findings was 7514. We developed an image-reading support system using deep learning for SBCE and obtained a good detection performance.

Intestinal intraepithelial lymphocytes (IELs) reside in the gut epithelial layer, where they help in maintaining intestinal homeostasis. Peripheral CD4+ T cells can develop into CD4+CD8αα+ IELs upon arrival at the gut epithelium via the lamina propria (LP). Although this specific differentiation of T cells is well established, the mechanisms preventing it from occurring in the LP remain unclear. Here, we show that chemokine receptor 9 (CCR9) expression is low in epithelial CD4+CD8αα+ IELs, but CCR9 deficiency results in CD4+CD8αα+ over-differentiation in both the epithelium and the LP. Single-cell RNA sequencing shows an enriched precursor cell cluster for CD4+CD8αα+ IELs in Ccr9 −/− mice. CD4+ T cells isolated from the epithelium of Ccr9 −/− mice also display increased expression of Cbfβ2, and the genomic occupancy modification of Cbfβ2 expression reveals its important function in CD4+CD8αα+ differentiation. These results implicate a link between CCR9 downregulation and Cbfb2 splicing upregulation to enhance CD4+CD8αα+ IEL differentiation.

Background and Aims: The effectiveness and durability of ustekinumab therapy with or without thiopurine immunomodulators (IMs) for ulcerative colitis (UC) in real-world Asian, Japanese patients have not yet been elucidated. Methods: To evaluate the additive effects of IMs on ustekinumab, a retrospective cohort study of UC patients receiving ustekinumab with or without thiopurine IMs, azathioprine or 6-mercaptopurine, was conducted from March 2020 to August 2021. The primary endpoint was clinical remission or response rate at week 8. The secondary endpoints were clinical remission or response rates at weeks 24 and 52, the durability of each treatment, and adverse events. Results: Of the 50 patients with UC treated with ustekinumab, 42 were enrolled. Sixteen patients were treated with a combination of ustekinumab and an IM. The clinical response rates of all patients at weeks 8, 24, and 52 were 53.7%, 63.3%, and 42.9%, respectively. There was no significant difference in the clinical responses or remission rates between the combination therapy and monotherapy groups at weeks 8, 24, and 52. (50.0% vs. 56.0%, P =. 757; 70.0% vs. 60.0%, P =. 702; and 42.9% vs. 42.9%, P = 1.00, respectively). A Kaplan-Meier analysis showed no difference in IM use on the durability of ustekinumab treatment (log-rank test; P =. 955). Conclusions: The response rate for Japanese UC patients is similar to previous reports based on American and European UC patients. There was no significant difference between the ustekinumab monotherapy group and the ustekinumab and IM combination group in the real world.

Background and Aim: Oral therapeutic and invasive endoscopy requires deep sedation to reduce patient distress due to prolonged examination and procedures. The usefulness of capnography and bispectral index (BIS) monitoring in the early hypoxia detection in oral therapeutic and invasive endoscopy has yet to be evaluated. This study aimed to investigate the clinical impact of capnography and BIS monitoring on hypoxic events during oral therapeutic and invasive endoscopic procedures. Methods: This is a prospective observational study. Trans-oral non-intubated therapeutic and/or invasive endoscopic procedures were performed with conventional monitoring (pulse oximetry, pulse, and blood pressure) as well as additional monitoring (BIS and end-tidal CO2 concentration). Hypoxia is defined as oxygen saturation of <90% that lasts >15 s. The clinical impact of capnography and BIS monitoring on hypoxic events during oral therapeutic and invasive endoscopic procedures were investigated with the risk factors for hypoxia in each patient. Results: Patients with hypoxia had significantly more apneas detected using capnography than other patients. The multivariate analysis revealed the detected apnea by capnography as an independent risk factor for hypoxia (odds ratio: 3.48[95% confidence interval: 1.24–9.78], P = 0.02). The BIS was not significantly different as a risk factor for hypoxia; however, per-event analysis revealed significantly decreased BIS values over time in 3 min before hypoxic events. Conclusions: Apnea detected by capnography was an independent predictor of hypoxia. The BIS value was not associated with hypoxia events; however, it showed a significant downward trend before hypoxia events.

Group 2 innate lymphoid cells (ILC2s) serve as frontline defenses against parasites. However, excluding helminth infections, it is poorly understood how ILC2s function in intestinal inflammation, including inflammatory bowel disease. Here, we analyzed the global gene expression of ILC2s in healthy and colitic conditions and revealed that type I interferon (T1IFN)-stimulated genes were up-regulated in ILC2s in dextran sodium sulfate (DSS)-induced colitis. The enhancement of T1IFN signaling in ILC2s in DSS-induced colitis was correlated with the downregulation of cytokine production by ILC2s, such as interleukin-5. Blocking T1IFN signaling during colitis resulted in exaggeration of colitis in both wild-type and Rag2-deficient mice. The exacerbation of colitis induced by neutralization of T1IFN signaling was accompanied by reduction of amphiregulin (AREG) in ILC2s and was partially rescued by exogenous AREG treatment. Collectively, these findings show the potential roles of T1IFN in ILC2s that contribute to colitis manifestation.

Background and Aim: Percutaneous endoscopic gastrostomy (PEG) has been used in patients with dysphagia and inadequate food intake via an oral route. Despite being a procedure with a high success rate, complications and death have been reported. The aim was to identify the factors related to major complications and mortality, as well as PEG removal prognostic factors due to improvement of their general condition. Methods: Patient characteristics, comorbidities, laboratory data, concomitant medication, sedation, and indication for PEG placement were collected. Major complications, mortality, and PEG removal factors were assessed. Results: A total of 388 patients were enrolled. There were 15 (3.9%) cases of major complications, with major bleeding being the most frequent in 6 (1.5%) patients. Corticosteroids were the independent variable associated with major complications (odds ratio [OR] 5.85; 95% confidence interval [CI] 1.71–20; P = <0.01). Advanced cancer (hazard ratio [HR] 0.5; 95% CI 0.3–1; P = 0.05), albumin (HR 0.6; 95% CI 0.4–0.9; P = <0.01), and C-reactive protein (CRP) (HR 1.1; CI 1–1.2; P = 0.01) were considered risk factors for mortality. Previous pneumonia (HR 0.4; CI 0.2–0.9; P = 0.02) was a factor for permanent use of a PEG; however, oncological indication (HR 8.2; CI 3.2–21; P = <0.01) was factors for PEG withdrawal. Conclusions: Chronic corticosteroid users potentially present with major complications. Low albumin levels and elevated CRP were associated with death. Previous aspiration pneumonia was a factor associated with permanent use of PEG; however, patients with oncological indication were the most benefited.

Objectives: Peutz–Jeghers syndrome (PJS) is a rare autosomal dominant hereditary disease with a clinical features related to gastrointestinal (GI) hamartomatous polyposis, frequently observed in the small bowel. Balloon-assisted enteroscopy (BAE) has made non-surgical treatment of GI polyps possible. Endoscopic mucosal resection (EMR) has been performed but was associated with complications and difficulties. Recently, endoscopic ischemic polypectomy (EIP) has been developed and its usefulness reported. The study evaluated the feasibility and safety of EIP and the clinical outcomes of patients with PJS. Methods: We retrospectively collected data of consecutive patients with PJS between September 2009 and March 2021. Data regarding clinical characteristics, follow-up methods, endoscopic management, and complications were collected. EIP feasibility and safety were assessed. Results: Twenty-two patients were included. The observation period was 70 months (range, 5–153). Of the 124 therapeutic endoscopy procedures performed, 68 used BAE. Of the 607 polyps treated, 329 polyps were located in the small bowel. EIP was able to treat a greater number of polyps per patient than EMR (P < 0.003), without any complications, carcinoma, or intussusception in the small bowel (P < 0.001). During the follow-up period, 3 patients developed GI cancer. Conclusion: Long-term follow-up in patients with PJS showed that EIP was a feasible and safe technique.

Background: Research on whether gastrointestinal symptoms correlate with the severity of Coronavirus Disease 2019 (COVID-19) has been inconclusive. This study aimed to clarify any associations between gastrointestinal symptoms and the prognosis of COVID-19. Methods: We collected data from the Japanese nationwide registry for COVID-19 to conduct a retrospective cohort study. Data from 3498 Japanese COVID-19 patients, diagnosed at 74 facilities between February 2020 and August 2022, were analyzed in this study. Hospitalized patients were followed up until discharge or transfer to another hospital. Outpatients were observed until the end of treatment. Associations between gastrointestinal symptoms and clinical outcomes were investigated using multivariable-adjusted logistic regression models. Results: The prevalence of diarrhea, nausea/vomiting, abdominal pain, and melena were 16.6% (581/3498), 8.9% (311/3498), 3.5% (121/3498), and 0.7% (23/3498), respectively. In the univariable analysis, admission to intensive care unit (ICU) and requirement for mechanical ventilation were less common in patients with diarrhea than those without (ICU, 15.7% vs. 20.6% (p = 0.006); mechanical ventilation, 7.9% vs. 11.4% (p = 0.013)). In the multivariable-adjusted analysis, diarrhea was associated with lower likelihood of ICU admission (adjusted odds ratio (aOR), 0.70; 95% confidence interval (CI), 0.53–0.92) and mechanical ventilation (aOR, 0.61; 95% CI, 0.42–0.89). Similar results were obtained in a sensitivity analysis with another logistic regression model that adjusted for 14 possible covariates with diarrhea (ICU; aOR, 0.70; 95% CI, 0.53–0.93; mechanical ventilation; aOR 0.62; 95% CI, 0.42–0.92). Conclusions: Diarrhea was associated with better clinical outcomes in COVID-19 patients.

Balloon-assisted enteroscopy allows endoscopic treatments in the deeper segments of the small bowel. Endoscopic balloon dilation has become a popular minimally invasive alternative for the treatment of Crohn's disease-associated small intestinal strictures. As a supplement to the Clinical Practice Guidelines for Enteroscopy, the Japan Gastroenterological Endoscopy Society's Working Committee has developed the present “Guidelines for endoscopic balloon dilation in treating Crohn's disease-associated small intestinal strictures,” based on new scientific techniques and evidence. The guidelines cover standard procedures for the insertion route of the balloon endoscope, bowel preparation, indications, procedure-related complications, efficacy, target diameter and duration, management of multiple strictures, and the current state of combined and alternative treatments. Unresolved future research questions are also listed in this guideline.

Sedation in gastroenterological endoscopy has become an important medical option in routine clinical care. Here, the Japan Gastroenterological Endoscopy Society and the Japanese Society of Anesthesiologists together provide the revised “Guidelines for sedation in gastroenterological endoscopy” as a second edition to address on-site clinical questions and issues raised for safe examination and treatment using sedated endoscopy. Twenty clinical questions were determined and the strength of recommendation and evidence quality (strength) were expressed according to the “MINDS Manual for Guideline Development 2017.” We were able to release up-to-date statements related to clinical questions and current issues relevant to sedation in gastroenterological endoscopy (henceforth, “endoscopy”). There are few reports from Japan in this field (e.g., meta-analyses), and many aspects have been based only on a specialist consensus. In the current scenario, benzodiazepine drugs primarily used for sedation during gastroenterological endoscopy are not approved by national health insurance in Japan, and investigations regarding expense-related disadvantages have not been conducted. Furthermore, including the perspective of beneficiaries (i.e., patients and citizens) during the creation of clinical guidelines should be considered. These guidelines are standardized based on up-to-date evidence quality (strength) and supports on-site clinical decision-making by patients and medical staff. Therefore, these guidelines need to be flexible with regard to the wishes, age, complications, and social conditions of the patient, as well as the conditions of the facility and discretion of the physician.

Intestinal intraepithelial lymphocytes (IELs), the first line of defense against microbial and dietary antigens, are classified as natural or induced based on their origin and receptor expression. Induced CD4+CD8αα+TCRβ+ T cells (double positive, DPIELs) originated from CD4+CD8α−TCRβ+ T cells (single positive, SPIELs) increase with aging. However, the metabolic requirements and the metabolic-related genes in IEL development remain unclear. We determined that the intraepithelial compartment is hypoxic in the presence of microbes and DPIELs increased more than natural IELs in this location. Moreover, DPIELs consumed less oxygen and glucose and exhibited unique alterations in mitochondria. Using inhibitors and genetically modified mice, we revealed that DPIELs adapt to their surrounding oxygen-deprived environment in peripheral tissues by modulating specific genes, including hypoxia-inducible factor, mammalian target of rapamycin complexes (mTORC), phosphorylated ribosomal protein S6 (pS6), and other glycolytic factors. Our findings provide valuable insight into the metabolic properties of IELs.

Background and objective: Leucine-rich alpha-2 glycoprotein (LRG) is a novel biomarker for Crohn’s disease (CD). The utility of combination use of LRG and C-reactive protein (CRP) has not been reported. This study aimed to investigate the diagnostic performance of LRG in combination with CRP to predict endoscopic activity. Methods: A single-centre, retrospective, cross-sectional study was conducted. Patients with CD who had serum LRG concentrations measured at least once between June 2020 and May 2021 were enrolled. Clinical activity was evaluated with the Harvey–Bradshaw Index (HBI). Spearman’s rank correlation coefficient (rs) was used to analyse the correlations between the HBI, LRG concentrations and CRP concentrations. In patients undergoing ileocolonoscopy or balloon-assisted enteroscopy within 60 days before or after LRG measurement, endoscopic activity was evaluated with the simple endoscopic score for Crohn’s disease (SES-CD). The diagnostic performance of LRG and CRP for endoscopic activity was evaluated using receiver operating characteristic (ROC) analysis. Results: Four hundred and eighty-nine measurements in 343 patients were analysed. Although a strong correlation was found between LRG and CRP concentrations (rs = 0.75), the HBI did not well correlate with LRG or CRP concentrations. Endoscopic activity was analysed in 56 patients. In diagnosing endoscopically moderate to severe activity (SES-CD > 6), the area under the ROC curve of LRG was greater than that of CRP (0.74 vs. 0.63; p = .037). The optimal cut-off value estimated by Youden’s index was 15.5 µg/mL for LRG, and 0.13 mg/dL for CRP. LRG and CRP concentrations were considered positive when they were above these cut-off values, and the sensitivity and specificity for an SES-CD > 6 were 58.3% and 93.8%, respectively. Dual positivity of LRG and CRP showed the highest specificity. Conclusions: Combination use of dual positive LRG and CRP is useful for diagnosing endoscopically moderate to severe disease.

Background and Aim: The adenoma detection rate is an important indicator of colonoscopy quality and colorectal cancer incidence. We compared the adenoma detection rates between white light imaging (WLI) and linked color imaging (LCI) colonoscopy. Methods: Patients undergoing colonoscopy for positive fecal immunochemical tests, follow-up of colon polyps, and abdominal symptoms at three institutions were randomly assigned to the LCI or WLI groups. Mean adenoma number per patient (including based on endoscopists' experience), adenoma detection rate, cecal intubation time, withdrawal time, mean adenoma number per location, and adenoma size were compared. Results: The LCI and WLI groups comprised 494 and 501 patients, respectively. No significant differences in the cecal intubation rate (LCI vs WLI: 99.5% vs 99.4%), cecal intubation time, and withdrawal time were noted between groups. The mean adenoma number per patient was significantly higher in the LCI group than in the WLI group (1.07 vs 0.88, P = 0.04), particularly in the descending [0.12 (58/494) vs 0.07 (35/501), P = 0.01] and sigmoid colon [0.41 (201/494) vs 0.30 (149/501), P ≤ 0.001]. However, the adenoma detection rate was 47.1% in the LCI group and 46.9% in the WLI group, with no significant difference (P = 0.93). The total number of sessile-type adenomas was significantly higher in the LCI group than in the WLI group (346/494 vs 278/501, P = 0.04). As for polyp size, small polyps (≤ 5 mm) were detected at a significantly higher rate in the LCI group (271/494 vs 336/501, P = 0.04). Conclusion: Linked color imaging is significantly superior to WLI in terms of mean adenoma number per patient.

BACKGROUND Evidence has been published on the successful applications of the anti-tumor necrosis factor alpha antibody infliximab, such as induction therapy, salvage treatment for acute cellular rejection, and treatment for chronic ulcerative inflammation, in intestinal transplant recipients. However, the optimal protocol for the effective use of infliximab remains largely undetermined due to scarcity of available clinical data. We report a continuative application of infliximab as maintenance therapy for recurrent chronic ulcerative ileitis in a recipient of isolated intestinal transplantation (ITx). CASE SUMMARY The patient was a 11-year-old boy with intestinal motility disorder classified as a hypogenic type of intestinal dysganglionosis. The patient underwent living-donor related intestinal transplant. His immunosuppression regimen consisted of daclizumab, tacrolimus, and steroids. Although he did not show rejection while on tacrolimus monotherapy, routine screening endoscopy showed several ulcerative lesions in the distal end of the graft 2 years after the intestinal transplant. Endoscopic work up to evaluate the progression of anemia revealed stenosis with ulcerative inflammatory changes and multiple longitudinal ulcers in the graft. Since the endoscopic findings suggested ulcerative lesions in Crohn's disease, infliximab treatment was considered. Treatment with infliximab and a small dose of oral prednisolone afforded successful withdrawal of total parenteral nutrition and maintenance of a well-functioning graft without infectious complications for 5 years since the administration of the first dose of infliximab. CONCLUSION Infliximab is effective as maintenance therapy for recurrent chronic ulcerative ileitis in an isolated ITx patient.

Background and Aims: We determined the factors influencing total capsule colonoscopy, adequate cleansing, and detectability of second-generation colon capsule endoscopy (CCE) for colorectal polyps or tumors (CRTs), adverse events, and acceptability. Methods: Among 44 Japanese hospitals, 1006 patients with suspected or documented colorectal diseases who underwent CCE were enrolled prospectively. Results: The total capsule colonoscopy rate was 86.1%. Age younger than 63 years (adjusted odds ratio [aOR], 1.525), male sex (aOR, 1.496), inflammatory bowel disease (aOR, 1.889), lavage intake on day –1 (aOR, 1.625), ≥1800-mL lavage intake on day 0 (aOR, .595), prokinetics on day 0 (aOR, .608), and ≥30-mL castor oil booster on day 0 (aOR, 1.734) were significant independent predictors. The overall adequate cleansing rate was 65.5%. Constipation (aOR, .527), lavage intake on day –1 (aOR, 1.822), laxative intake on day –1 (aOR, 2.616), and ≥1900-mL lavage intake on day 0 (aOR, 1.449) were significant independent predictors. The detection rates for patients with CRTs ≥6 mm and ≥10 mm were 92% (95% confidence interval, 84-97) and 89% (95% confidence interval, 78-96), respectively. Inadequate cleansing in the ascending colon (aOR, .184), ≥6-mm CRT in the transverse colon (aOR, 4.703), and ≥6-mm CRT in the left-sided colon (aOR, 32.013) were significant independent predictors. CCE retention occurred in 2 patients (.20%) requiring endoscopic and surgical interventions. In total, 63% of patients desired CCE for their next colonoscopy. Conclusions: CCE was relatively safe, well tolerated, and useful for detecting colorectal lesions when adequate bowel preparation was made. (Clinical trial registration number: UMIN000021936.)

Background and Aim: In patients with Crohn’s disease (CD) and small bowel stenosis, endoscopic balloon dilation (EBD) is considered to be useful in improving stenotic symptoms and avoiding surgery. However, it carries risks such as bleeding and perforation. The aim of this study was to identify the indications for endoscopic intervention in patients with CD and small bowel stenosis. Methods: From November 2007 to March 2020, 143 CD patients with small bowel stenosis were enrolled in this study. We identified the factors associated with not requiring endoscopic intervention during long-term follow-up of these patients. Results: Forty of the 143 patients had abdominal symptoms of stenosis and had undergone EBD, whereas the remaining 103 were asymptomatic and had not undergone endoscopic intervention. During long-term follow-up, 95 of those 103 patients never required endoscopic or surgical intervention. Multivariate logistic regression analysis revealed that not consuming an elemental diet (OR 3.18, 95% CI 1.48–6.82; p <.01) and ileocecal valve (ICV) stenosis (OR 0.30, 95% CI 0.11–0.83; p =.02) were independently associated with not requiring EBD. The cumulative emergency hospitalisation-free rate also tended to be higher in patients not consuming an elemental diet or with ICV stenosis. Conclusions: Two factors, namely not consuming an elemental diet and ICV stenosis, predict a long-term intervention-free prognosis in CD patients with small bowel stenosis.Key messages When an endoscopically impassable small bowel stenosis is found in a CD patient, long-term follow-up without endoscopic intervention may be possible if the patient is asymptomatic, is not using an elemental diet, and the stenosis is ICV.

Background: Endoscopic phenotypes of pouchitis according to the Chicago Classification have been reported to be associated with poor pouch outcomes in ulcerative colitis (UC). Here, we aimed to assess the prevalence of endoscopic phenotypes and their predictability for pouch outcomes. Methods: This retrospective multicenter study included UC patients aged 18 years or older who underwent total colectomy between January 2000 and March 2020. The primary endpoints were frequencies of endoscopic phenotypes of the Chicago Classification and their predictability for chronic pouchitis and pouch failure. Endoscopic findings were evaluated at the initial pouchoscopy and at 3 and 10 years after ileostomy takedown. Results: A total of 392 eligible patients were identified. The frequencies of chronic pouchitis and pouch failure were 32% and 4.9%, respectively. Focal inflammation and inlet involvement at the initial postoperative pouchoscopy were significantly associated with subsequent risk of chronic pouchitis and pouch failure, respectively. Thirty percent of the patients with focal inflammation progressed to diffuse inflammation when chronic pouchitis developed. Multivariate analysis showed chronic pouchitis was significantly associated with diffuse inflammation and cuffitis observed throughout the clinical course. The proportion of pouch-related fistula was significantly lower in our cohort than in the US cohort (4.8% vs 19%, P < 0.001), and pouch-related fistula was an independent risk factor for pouch failure. Conclusions: We demonstrated the predictability of the Chicago Classification for pouch outcomes, and a lower prevalence of pouch-related fistula, resulting in a lower pouch failure risk in our multicenter cohort.

Background/Aims: Thromboprophylaxis is recommended for hospitalized patients with inflammatory bowel disease (IBD) in Western countries, although it is selectively administered to high-risk patients in East Asia. A central venous catheter (CVC) is commonly placed in patients with IBD. Although CVC placement is considered a risk factor for venous thromboembolism (VTE), the degree of increased risk in patients with IBD is uncertain. This study aimed to identify the risk of VTE with CVC placement in hospitalized Japanese patients with IBD without thromboprophylaxis. Methods: This retrospective cohort study included patients with ulcerative colitis or Crohn’s disease who were admitted for disease flares at Keio University Hospital between January 2016 and December 2020. Patients who already had thrombosis or were administered any antithrombotic treatment on admission were excluded. VTE development during the hospitalization was surveyed, and VTE risk associated with CVC indwelling was estimated using propensity score matching and inverse probability of treatment weighting analyses. Results: Altogether, 497 hospitalized patients with IBD (ulcerative colitis, 327; Crohn’s disease, 170) were enrolled. VTE developed in 9.30% (12/129) of catheterized patients and in 0.82% (3/368) of non-catheterized patients. The propensity score matching yielded 127 matched pairs of patients. The catheterized group demonstrated higher odds for VTE than the non-catheterized group (odds ratio, 13.15; 95% confidence interval, 1.68–102.70). A similar result was obtained in the inverse probability of treatment weighting analysis (odds ratio, 11.02; 95% confidence interval, 2.64–46.10). Conclusions: CVC placement is a major risk factor for VTE among hospitalized Japanese patients with IBD without thromboprophylaxis.

Background and Aim: We retrospectively determined the safety and efficacy of the endoscopic delivery (ED) of capsule endoscopes. Methods: We enrolled 10,156 patients who underwent small bowel capsule endoscopy (SBCE), 3182 who underwent patency capsule (PC), and 1367 who underwent colon capsule endoscopy (CCE), at 11 gastroenterological and nine pediatric centers. Results: Small bowel capsule endoscopies, PCs, and CCEs were endoscopically delivered to 546 (5.4%), 214 (6.7%), and 14 (1.0%) patients, respectively. Only mild complications occurred for 21.6% (167/774), including uneventful mucosal damage, bleeding, and abdominal pain. Successful ED of SBCE to the duodenum or jejunum occurred in 91.8% and 90.7% of patients aged <16 years and ≥16 years, respectively (P = 0.6661), but the total enteroscopy rate was higher in the first group (91.7%) than in the second (76.2%, P < 0.0001), for whom impossible ingestion (87.3%) was significantly more common than prolonged lodging in the stomach (64.2%, P = 0.0010). Successful PC and CCE delivery to the duodenum occurred in 84.1% and 28.6%, thereafter the patency confirmation rate and total colonoscopy rate was 100% and 61.5%, respectively. The height, weight, and age cutoff points in predicting spontaneous ingestion were 132 cm, 24.8 kg, and 9 years 2 months, respectively, in patients aged <16 years. Patients aged ≥16 years could not swallow the SBCEs mainly due to dysphagia (75.0%); those who retained it in the esophagus due to cardiac disease (28.6%), etc. and in the stomach due to diabetes mellitus (15.7%), etc. Conclusions: This large-scale study supports the safety and efficacy of ED in adult and pediatric patients. UMIN000042020.