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Background/Aims Improving quality of life has been gaining importance in ulcerative colitis (UC) management. The aim of this study was to investigate changes in health-related quality of life (HRQL) and related factors in patients with moderate-to-severe UC. Methods A multicenter, hospital-based, prospective study was performed using a Moderateto- Severe Ulcerative Colitis Cohort in Korea (the MOSAIK). Changes in HRQL, evaluated using the 12-Item Short Form Health Survey (SF-12) and Inflammatory Bowel Disease Questionnaire (IBDQ), were analyzed at the time of diagnosis and 1 year later. Results In a sample of 276 patients, the mean age was 38.4 years, and the majority of patients were male (59.8%). HRQL tended to increase in both the IBDQ and SF-12 1 year after diagnosis. A higher partial Mayo score was significantly related to poorer HRQL on the IBDQ and SF-12 in a linear mixed model (p

Background/Aims Few studies have investigated terminal ileal lesions and their prognostic value in patients with ulcerative colitis (UC). We evaluated the clinical significance of these lesions as a prognostic factor in patients with UC who were in clinical remission. Methods We retrospectively selected 567 of 4,066 colonoscopy reports that included positive findings from orificial observations of the terminal ileum (TI) and appendix in patients with UC. We finally recruited patients who were in clinical remission (n=204). We compared the clinical courses, including relapse and other prognostic parameters associated with UC, between the groups. Results The baseline patient characteristics were not significantly different between patients with (n=69, TI+ group) and without TI lesions (n=135, TI– group), although there were more never-smokers in the TI+ group (n=57 [82.6%] in the TI+ group; n=86 [63.7%] in the TI– group; p=0.005). Of note, appendiceal orifice inflammation (AOI) was less frequently found in the TI+ group (14.5%) than in the TI– group (71.9%, p

Background/Aims Previous studies have investigated the relationship between visceral obesity and the risk of colorectal tumors. Visceral obesity may affect the outcome of colorectal cancer (CRC), including survival and metastasis. We investigated the associations between visceral adipose tissue and oncologic outcomes in stage III CRC. Methods Four hundred seventy-two patients with stage III CRC were identified. Subcutaneous and visceral adipose tissue areas were measured volumetrically via computed tomography for each patient at different levels of the lumbar spine. After adjusting for age, sex, and other clinical factors, the effects of visceral adipose tissue area on mortality and recurrence were assessed using Cox proportional hazard regression. Results In univariate and multivariate analyses, a higher visceral adipose tissue to total adipose tissue (VT) ratio (hazard ratio [HR], 1.041; 95% CI, 1.008 to 1.075; p=0.015) and higher visceral adipose tissue to subcutaneous adipose tissue (VS) ratio (HR, 1.016; 95% CI, 1.005 to 1.028; p=0.006) were both associated with poor CRC-specific survival. Interestingly, in the evaluation of each site of recurrence, a higher VT ratio (HR, 1.069; 95% CI, 1.010 to 1.131; p=0.020) and higher VS ratio (HR, 1.024; 95% CI, 1.003 to 1.045; p=0.023) were both related to a higher risk of peritoneal seeding and tumor recurrence. The VT ratio at the L3-L4 level was significantly associated with a higher risk of peritoneal seeding and tumor recurrence (HR, 4.969; 95% CI, 1.303 to 18.949; p=0.019), while other levels showed no such relationship. Conclusions Visceral obesity is closely related to increased risks of CRC-specific mortality and peritoneal seeding metastasis in stage III CRC patients.

Background and Aims Robust evidence regarding the impact of disease activity on pregnancy outcomes in women with inflammatory bowel disease [IBD] is crucial for both clinicians and patients in preparing a birth plan. We sought to perform a systematic review and meta-analysis to assess the pooled influences of disease activity on pregnancy outcomes in women with IBD. Methods We searched MEDLINE, EMBASE and the COCHRANE library to identify articles comparing pregnancy outcomes between active and inactive IBD at the time of conception or during pregnancy. A meta-analysis was performed using a random-effects model to pool estimates and report odds ratios [ORs]. Results A total of 28 studies were identified as eligible for the meta-analysis. In women with active IBD, the pooled ORs for low birth weight [LBW], preterm birth, small for gestational age [SGA], spontaneous abortion and stillbirths were respectively 3.81 (95% confidence interval [CI] 1.81–8.02), 2.42 [95% CI 1.74–3.35], 1.48 [95% CI 1.19–1.85], 1.87 [95% CI 1.17–3.0] and 2.27 [95% CI 1.03–5.04] compared to women with inactive IBD. In the subgroup analysis based on disease type, women with active ulcerative colitis had an increased risk of LBW, preterm birth and spontaneous abortion. Women with active Crohn’s disease had a higher risk of preterm birth, SGA and spontaneous abortion. Conclusions Active IBD during the periconception period and pregnancy is associated with an increased risk of adverse pregnancy outcomes. Our data suggest that pregnancy should be planned when the disease is quiescent, and continuous disease control is important even during pregnancy.

Inflammatory bowel disease (IBD), comprised of Crohn’s disease and ulcerative colitis, is a chronic, relapsing, and remitting disease of the gastrointestinal tract whose incidence is rising worldwide, especially in East Asian countries. The etiopathogenesis of IBD remains poorly understood. It is currently considered that a combination of genetic and environmental factors triggers an aberrant immune response against the commensal intestinal flora in IBD patients. Over the past decades, advances in the knowledge of the inflammatory cascade involved in IBD pathogenesis have expanded the pharmacological armamentarium in IBD. Actually, the introduction of specific biological therapies, including anti- tumor necrosis factor, anti-interleukin- 12/23, and anti-integrin, has revolutionized the treatment of IBD. Moreover, small molecule agents such as Janus kinase inhibitors also now under clinical use. In IBD, a substantial number of patient accompanies various articular manifestations and, rheumatic involvement is one of the most common extra-intestinal symptoms. Many of the mechanisms based drugs described above have already been used in rheumatic diseases. In addition, some of those drugs can be used to treat both IBD itself and accompanied rheumatic involvement, however there are differences in drug usage between these two indications. This review aims to briefly review the mechanism-based drug therapies of IBD with particular reference to rheumatic disease. (J Rheum Dis 2020;27:128-135)

Background/Aims: A considerable number of patients with Crohn’s disease still need intestinal resection surgery. Postoperative recurrence is an important issue in Crohn’s disease management, including the selection of high-risk patients. Eastern Asian patients showed several differences from Caucasian patients. Therefore, we investigated the postoperative surgical recurrence outcome and identified risk factors in Korean patients. Methods: Clinical data of 372 patients with Crohn’s disease who underwent first intestinal resection between January 2004 and August 2014 at 14 hospitals in Korea were retrospectively reviewed. Results: Over the follow-up period, 50 patients (17.1%) showed surgi cal recurrence. The cumulative surgical recurrence rate was 6.5% at 1 year and 15.4% at 7 years. Age under 16 (p=0.011; hazard ratio [HR], 5.136; 95% confidence interval [CI], 1.576 to 16.731), colonic involvement (p=0.023; HR , 2.011; 95% CI, 1.102 to 3.670), and the presence of perianal disease at surgery (p=0.008; HR, 2.239; 95% CI, 1.236 to 4.059) were independent risk factors associated with surgical recurrence. Postoperative thiopurine treatment (p=0.002; HR, 0.393; 95% CI, 0.218 to 0.710) was a protective factor for surgical recurrence. Conclusions: Among the disease characteristics at surgery, younger age, colonic location, and perianal le sions were independent risk factors for surgical recurrence. Postoperative thiopurine treatment significantly reduced the incidence of surgical recurrence. (Gut Liver 2020;14:331-337)

Supplemental Digital Content is available in the text., Goals: We assessed the efficacy of polaprezinc plus proton pump inhibitor (PPI) treatment for endoscopic submucosal dissection (ESD)-induced ulcer healing compared with rebamipide plus PPI treatment. Background: ESD has been widely used as a local treatment option that cures gastric neoplasms. However, it causes large and deep artificial ulcers, and there are no guidelines with regard to the optimal treatment durations and drug regimens for ESD-induced ulcers. Polaprezinc is effective for promoting ulcer healing and helps enhance the quality of ulcer healing. Study: Two hundred ten patients with ESD-induced ulcers were randomly allocated to treatment with polaprezinc (150 mg/d) plus pantoprazole (40 mg/d) or treatment with rebamipide (300 mg/d) plus pantoprazole (40 mg/d). We evaluated the ulcer healing rate and condition of the ulcer at 4 weeks after dissection. The χ2 or Fisher exact test and the Student t test were used. Results: The ulcer healing rates at 4 weeks after dissection in the polaprezinc plus pantoprazole treatment group were not inferior compared with those in the rebamipide plus pantoprazole treatment group, both in the intention-to-treat analysis (90.3% and 91.4%, respectively, P=0.523) and per-protocol analysis (89.9% and 91.1%, respectively, P=0.531). The short procedure time was an independent predictive factor for a high ulcer healing rate (odds ratio: 0.975; 95% confidence interval: 0.958-0.993; P=0.006). Conclusion: The polaprezinc plus PPI treatment showed noninferiority to rebamipide plus PPI treatment in the ulcer healing rate at 4 weeks after ESD.

The treatment of inflammatory bowel disease (IBD) has been revolutionized for the last 10 years by the increasing use of im munomodulators and biologics. With immunosuppression of this kind, opportunistic infection is an important safety concern for patients with IBD. In particular, viral hepatitis is determined by the interaction between the virus and the host’s immunity, and the risk of reactivation increases if immunity is compromised by immunosuppression therapy. Parts of Asia, including Korea, still show intermediate endemicity for the hepatitis A virus and hepatitis B virus compared with the United States and Western Europe. Thus, members of IBD research group of the Korean Association for the Study of Intestinal Diseases have pro duced a guideline on the prevention and management of viral hepatitis in IBD. (Intest Res 2020;18:18-33)

Patients with early gastric cancer (EGC) who undergo non-curative endoscopic resection (ER) require additional surgery. The aim of the study was to validate surgical and oncological outcomes according to the timing of additional surgery after non-curative endoscopic resection. We retrospectively analyzed long-term follow-up data on the 302 patients enrolled between January 2007 and December 2014. We validated our earlier suggestion that the optimal time interval from non-curative ER to additional surgery was 29 days. All patients were divided into two groups by reference to time intervals from ER to additional surgery of ≤29days (n = 133; group A) and >29 days (n = 169; group B). The median follow-up duration was 41.98 ± 21.23 months. As in our previous study, group B exhibited better surgical outcomes. A total of 10 patients developed locoregional or distant recurrences during the follow-up period, but no significant difference was evident between the two groups. Interestingly, the survival rate was better in group B. Group B (>29 days) exhibited better surgical and oncological outcomes. Thus, additional gastrectomy after non-curative ER should be delayed for 1 month to ensure optimal surgical and oncological outcomes.

Background/Aims: Bicarbonate-containing alginate formula tions are reported to be effective for controlling reflux symp toms. However, the efficacy of Lamina G alginate without gas production has not been reported. The aim is to evaluate the efficacy of a non-bicarbonate alginate in individuals with reflux symptoms without reflux esophagitis. Methods: Par ticipants who had experienced heartburn or regurgitation for 7 consecutive days were randomized to one of the following treatment groups: proton pump inhibitors (PPI) plus alginate (combination) or PPI plus placebo (PPI only). In addition, as a reference group, patients received placebo plus alginate (alginate only). The primary endpoint compared the percent age of patients with complete resolution of symptoms for the final 7 days of the treatment. Secondary endpoints com pared changes in symptom score, symptom-free days during the treatment period, the Reflux Disease Questionnaire, Pa tient Assessment of Upper Gastrointestinal Disorders (PAGI)-Quality of Life and PAGI-Symptoms Severity Index scores, the investigator’s assessment of symptoms, and incidence of ad verse events. Results: Complete resolution of heartburn or regurgitation was not significantly different between the com bination and PPI only groups (58.7% vs 57.5%, p=0.903). The secondary endpoints were not significantly different between the two groups. Complete resolution of heartburn or regurgitation, did not differ between the alginate only reference group and the PPI only group (75.0% vs 57.5%, p=0.146). Conclusions: The addition of non-bicarbonate al ginate to PPI was no more effective than PPI alone in control ling reflux symptoms. (Gut Liver 2019;13:642-648)

This letter introduces a novel anti-skid foot design consisting of two different types of foot pads, a cylindrical foot covered with rubber and a complementary foot with an array of spine mechanisms. The primary foot is designed to provide contact during movements that do not require excessive friction forces. On the other hand, the complementary foot is specialized to provide larger traction for dynamic motions. A passive slip detection and lock & release mechanisms are also designed to enable conditional switching to the complementary foot pad if slip occurs while the primary foot is in use. Experimental results demonstrated that the anti-skid foot can sustain 1.9 times of tangential load on a concrete block, compared with the maximum tangential load that a rubber foot pad can sustain on the same surface. Using this enhanced tangential load capability, a two-legged planar robot equipped with the novel foot was able to jump, land, and attach to the surface of a concrete block with a slope of 50 $^{\circ }$ .

Aim: This study examined the real-world effectiveness and safety outcomes of vedolizumab in ulcerative colitis (UC) patients who had failed anti-tumor necrosis factor (anti-TNF) therapy in Korea. Methods: A retrospective chart review study was conducted in adults with moderate to severely active UC who had failed anti-TNF agents and subsequently received vedolizumab. Clinical response and clinical remission at week 6 and 14 after vedolizumab initiation was evaluated. Safety outcomes were also reported. Outcome rates were compared with a matched sub-cohort derived from the open-label sub-cohort of the GEMINI 1 trial using the optimal matching method. Results: A total of 105 patients (mean age, 45.3 years; 63.8% male) were included. At week 6, 55.8% ( n = 43/77) achieved a clinical response and 18.2% ( n = 14/77) achieved clinical remission. At week 14, 73.2% ( n = 52/71) achieved a clinical response and 39.4% ( n = 28/71) achieved clinical remission. When non-response imputation was used, the clinical response rate at week 6 and week 14 were 40.1% ( n = 43/105) and 49.5% ( n = 52/105) respectively. Of the 105 patients, 16 (15.2%) experienced at least one adverse event. The matched analysis showed that the clinical response rate at week 6 was higher in the matched sub-cohort of this study (24/47, 51.1%) versus the matched sub-cohort from the GEMINI 1 open-label cohort (12/47, 34.3%, p = 0.019). The clinical remission rates at week 6 were similar (7/47, 14.9% versus 9/47, 19.1%, p = 0.785). Conclusions: In the real-world setting, vedolizumab is effective and well tolerated within the first 14 weeks of use in Korea. The proportion of patients experiencing clinical response and clinical remission at 6 and 14 weeks appeared to be largely consistent with that observed in real-world studies from other regions and populations.

Background/Aims: The optimal tools for monitoring Crohn’s disease (CD) are controversial. We compared radiology plus ileocolonoscopy and radiology alone in terms of prognosis prediction and evaluated the agreement between radiologic and ileocolonoscopic findings in patients with CD.Methods: Patients with CD who were followed up with computed tomography enterography (CTE) or magnetic resonance enterography (MRE) alone or CTE or MRE plus ileocolonoscopy were retrospectively recruited. Time to relapse was investigated to evaluate the difference in prognosis using the log-rank and Cox regression tests, and the agreement between radiologic and ileocolonoscopic findings was determined using a kappa value.Results: A total of 501 patients with CD in clinical remission who underwent CTE or MRE and/or ileocolonoscopy were analyzed. Of these, 372 (74.3%) patients underwent CTE or MRE alone and 129 (25.7%) patients underwent CTE or MRE plus ileocolonoscopy. The cumulative maintenance rate of clinical remission between the two groups was not significantly different (p = 0.526, log-rank test). In multivariate analysis, age

Background/Aims Many patients with Crohn's disease (CD) undergo intestinal resection during the disease course. Despite surgery, postoperative recurrence (POR) commonly occurs. Although postoperative use of tumor necrosis factor α (TNF-α) inhibitors is known to be effective in preventing POR, few studies have evaluated the effectiveness of continuing the same TNF-α inhibitors postoperatively in patients who received TNF-ɑ inhibitors before surgery. Methods This retrospective observational study was performed in a single tertiary medical center. We retrospectively reviewed patients who had undergone the first intestinal resection due to CD and divided them into two groups: TNF-α inhibitor users in both the preoperative and postoperative periods, and TNF-α inhibitor users in only the preoperative period. We compared the clinical outcomes between these two groups. Results In total, 45 patients who used TNF-α inhibitors preoperatively were recruited. Among them, TNF-α inhibitors were used postoperatively in 20 patients (44.4%). The baseline characteristics except age at diagnosis were similar in both groups. The rates of surgical and endoscopic recurrence were not different between the two groups, but the cumulative clinical recurrence rate was significantly lower in the postoperative TNF-α inhibitors group (log-rank p=0.003). In multivariate Cox regression analysis, postoperative TNF-α inhibitors use was significantly associated with a decreased risk of clinical recurrence (adjusted hazard ratio, 0.204; 95% confidence interval, 0.060 to 0.691; p=0.011). Conclusions Continuing TNF-α inhibitors postoperatively in patients who were receiving TNF-α inhibitors before surgery significantly reduced the rate of clinical recurrence. For patients with CD who received TNF-α inhibitors preoperatively, continuing their use after surgery could be recommended.

Familial adenomatous polyposis (FAP) is a hereditary disease characterized by the development of numerous colorectal adenomas in young adults. Metformin, an oral diabetic drug, has been shown to have antineoplastic effects and a favorable safety profile. We performed a randomized, double-blind, controlled trial to evaluate the efficacy of metformin on the regression of colorectal and duodenal adenoma in patients with FAP. Thirty-four FAP patients were randomly assigned in a 1:2:2 ratio to receive placebo, 500 mg metformin, or 1,500 mg metformin per day orally for 7 months. The number and size of polyps and the global polyp burden were evaluated before and after the intervention. This study was terminated early based on the results of the interim analysis. No significant differences were determined in the percentage change of colorectal and duodenal polyp number over the course of treatment among the three treatment arms (P = 0.627 and P = 1.000, respectively). We found no significant differences in the percentage change of colorectal or duodenal polyp size among the three groups (P = 0.214 and P = 0.803, respectively). The overall polyp burdens of the colorectum and duodenum were not significantly changed by metformin treatment at either dosage. Colon polyps removed from the metformin-treated patients showed significantly lower mTOR signal (p-S6) expression than those from patients in the placebo arm. In conclusion, 7 months of treatment with 500 mg or 1,500 mg metformin did not reduce the mean number or size of polyps in the colorectum or duodenum in FAP patients (ClinicalTrials.gov ID: NCT01725490). Prevention Relevance: A 7-month metformin treatment (500 mg or 1,500 mg) did not reduce the number or size of polyps in the colorectum or duodenum of FAP patients as compared to placebo. These results do not support the use of metformin to promote regression of intestinal adenomas in FAP patients.

BackgroundPatients with inflammatory bowel disease (IBD) and intestinal Behçet’s disease (BD) are vulnerable to micronutrient deficiencies due to diarrhea-related gastrointestinal loss and poor dietary intake caused by disease-related anorexia. However, few studies have investigated the incidence and risk factors for micronutrient deficiency.MethodsWe retrospectively analyzed 205 patients with IBD who underwent micronutrient examination, including folate, vitamin B12, 25-OH-vitamin D, and/or ferritin level quantification, with follow-up blood tests conducted 6 months later.ResultsEighty patients (39.0%), who were deficient in any of the four micronutrients, were classified as the deficiency group, and the remaining 125 (61.0%) were classified as the non-deficient group. Compared to those in the non-deficiency group, patients in the deficiency group were much younger, had more Crohn's disease (CD) patients, more patients with a history of bowel operation, and significantly less 5-amino salicylic acid usage. Multivariate analysis revealed that CD and bowel operation were significant independent factors associated with micronutrient deficiency.ConclusionsThe incidence of micronutrient deficiency was high (39.0%). Factors including CD, bowel operation, and younger ages were found to be associated with higher risks of deficiency. Therefore, patients with IBD, especially young patients with CD who have undergone bowel resection surgery, need more attention paid to micronutrition.

AIM To investigate the feasibility and safety of secondary endoscopic submucosal dissection (ESD) for residual or locally recurrent gastric tumors. METHODS Between 2010 and 2017, 1623 consecutive patients underwent ESD for gastric neoplasms at a single tertiary referral center. Among these, 28 patients underwent secondary ESD for a residual or locally recurrent tumor. Our analysis compared clinicopathologic factors between primary ESD and secondary ESD groups. RESULTS The en bloc resection and curative rate of resection of secondary ESD were 92.9% and 89.3%, respectively. The average procedure time of secondary ESD was significantly longer than primary ESD (78.2 min vs 55.1 min, P = 0.004), and the adverse events rate was not significantly different but trended slightly higher in the secondary ESD group compared to the primary ESD group (10.7% vs 3.8%, P = 0.095). Patients who received secondary ESD had favorable outcomes without severe adverse events. During a mean follow-up period, no local recurrence occurred in patients who received secondary ESD. CONCLUSION Secondary ESD of residual or locally recurrent gastric tumors appears to be a feasible and curative treatment though it requires greater technical efficiency and longer procedure time.

Background Peritoneal carcinomatosis can influence clinical outcomes of patients receiving self-expandable metal stents (SEMS) for malignant colorectal obstruction, but data regarding this issue are sparse. We analyzed the clinical outcomes of post-SEMS insertion for malignant colorectal obstruction based on carcinomatosis status. Methods Stent- and patient-related clinical outcomes were compared for carcinomatosis status in a retrospective review involving 323 consecutive patients (colorectal cancer 198 patients; extracolonic malignancy 125 patients) who underwent palliative SEMS placement for malignant colorectal obstruction from January 2005 to March 2012. Severity of carcinomatosis was classified as mild, moderate, or severe. Results Carcinomatosis was observed in 190 patients (58.8 %). The rates of technical (84.7 vs. 94.7 %; P = 0.005) and clinical (73.2 vs. 83.5 %; P = 0.03) success were lower in patients with vs. without carcinomatosis. Rates of early (2.1 % vs. 3.0 %; P = 0.72) and delayed (1.6 % vs. 6.0 %; P = 0.08) perforation and stent failure (27.9 % vs. 26.3 %; P = 0.75) showed no difference. Technical and clinical success rates were significantly different based on the severity of carcinomatosis (technical success rate: mild 90.7 %, moderate 97.4 %, severe 76.3 %, P = 0.003; clinical success rate: mild 83.3 %, moderate 82.1 %, severe 63.9 %, P = 0.01). In multivariate analysis, severe carcinomatosis was identified as an independent factor related to technical (odds ratio [OR] 0.18, 95 % confidence interval [CI] 0.06 – 0.56) and clinical (OR 0.33, 95 %CI 0.15 – 0.74) success. Conclusions Peritoneal carcinomatosis was associated with decreased technical and clinical success rates in patients receiving SEMS for malignant colorectal obstruction. Moreover, the presence of severe carcinomatosis was an independent factor determining these clinical outcomes.

Primary sclerosing cholangitis (PSC) is a rare progressive cholestatic liver disease of unknown causes, but is strongly associated with inflammatory bowel diseases (IBDs), particularly ulcerative colitis (UC). However, studies comparing risk factors and clinical courses of patients with concomitant UC and PSC with those of patients with PSC alone are lacking. We retrospectively reviewed patients with PSC diagnosed between 2005 and 2017 in four tertiary hospitals in Korea. We compared the risk factors and outcomes of concomitant UC and PSC (UC-PSC) and those of PSC alone. PSC was diagnosed in 50 patients in four different tertiary hospitals in Korea. Of them, 18 patients (36.0%) had UC-PSC and 32 patients (64.0%) had PSC alone. The median age at PSC diagnosis was younger in the UC-PSC group than that in the PSC alone group (37 vs. 54 years, P = 0.002). In multivariate analysis, older age at PSC diagnosis (P = 0.007; odds ratio [OR], 0.884; 95% confidence interval [CI], 0.808–0.966) and current smoking habit (P = 0.033; OR, 0.026; 95% CI, 0.001–0.748) were determined to be independent factors for reducing the possibility of developing concomitant UC after PSC. Additionally, UC-PSC was shown to be an independent risk factor for the development of colorectal dysplasia (P = 0.044; OR, 10.829; 95% CI, 1.065–110.127). Our analysis showed that UC-PSC is more likely to be negatively associated with current smoking and older age at the time of PSC diagnosis. Moreover, UC-PSC increased the risk of colorectal dysplasia.

Background/aims We explored Korean physicians' policies for surveillance of colorectal cancer (CRC) after curative surgery. Methods Web-based self-report questionnaires were developed. Invitations to participate were emailed to physicians who diagnosed and treated CRC from October 1 to November 15, 2015. The questionnaire consisted of the role doctors played in the surveillance, examination of surveillance, and duration of postoperative surveillance according to CRC stage or primary site of the cancer. Results Ninety-one physicians participated in the online survey, and 78 completed the survey. Sixty-seven participants (13%) answered "up to 5 years" for stage I surveillance duration; and 11 (13%) responded with a duration of g 5 years for stage I. A total of 61 (75%) responded with a surveillance duration of up to 5 years for stage II; and 19 (24%) responded with a duration of g 5 years for stage II. Sixty-seven (97%) and 61 (91%) physicians monitored patients with stage II/III every 3 or 6 months by laboratory examination and by abdominopelvic computed tomography scan for the first year, respectively. A total of 43 (53%) responded with a surveillance duration of up to 5 years for stage IV; and 46 (46%) responded with a duration of g 5 years for stage IV after curative resection. Conclusions Korean physicians mostly followed up CRC using intensive postoperative surveillance. In preference to monitoring over a comparatively shorter period of time, the physicians tended to prefer monitoring patients post-operatively over a g 5 year period, particularly in cases of advanced-stage CRC.

Summary of Event: A 2 cm-sized colonic perforation occurred during diagnostic colonoscopy. Endoscopic closure was performed immediately using detachable snare and conservative management with intravenous antibiotics was followed for several days. However, abdominal computed tomography showed huge abscess and its connection to the sigmoid colon. The patient underwent segmental colectomy, which revealed the incomplete closure of perforated lesion with severe serosal fibrotic change. Teaching Point: Endoscopic treatment of large-sized colonic perforations should be undertaken with caution since the possibility of incomplete closure is high. For large-sized colonic perforations, early surgical treatment should be preferentially considered over endoscopic treatment.

Background Inflammatory bowel disease (IBD) patients often experience disease flare-ups during international air travel. We aimed to evaluate the proportion of patients that experiences IBD flares during international air travel and identify risk factors associated with enhanced disease activity. Methods Patients with scheduled international air travel were enrolled in the study from the Seoul National University Bundang Hospital IBD clinic. Flight information and clinical data were collected via questionnaires and personal interviews, and risk factors associated with IBD flares were determined. Results Between May 2018 and February 2020, 94 patients were enrolled in the study (mean age, 33.0 years; males, 53.2%; mean disease duration, 56.7 months), including 56 (59.6%) with ulcerative colitis and 38 (40.4%) with Crohn’s disease. Of the 94 patients enrolled, 15 (16.0%) experienced an IBD flare-up and 79 (84.0%) remained in remission throughout travel. Logistic regression analysis revealed that high fecal calprotectin levels before travel (odds ratio [OR]: 1.001, 95% confidence interval [CI]: 1.000–1.001, p = 0.016), the presence of a comorbidity (OR: 6.334, 95% CI: 1.129–35.526, p = 0.036), and a prior emergency room visit (OR: 5.283, 95% CI: 1.085–25.724, p = 0.039) were positively associated with disease flare-up. The previous and current use of immunomodulators and biologics, time of flight, altitude, number countries visited, travel duration, objective of visit, and previous medical consultations were not associated with disease flare-up. Conclusion Factors including fecal calprotectin levels, prior visit(s) to the ER, and the presence of a comorbidity predicted IBD flare-up during international travel.

Background Many patients with Crohn’s disease undergo major abdominal surgery during the disease course. Despite surgery, postoperative recurrence (POR) commonly occurs. Although postoperative use of biologic agents is known to be effective in preventing POR, few studies have evaluated the effectiveness of continuing the same biologic agents postoperatively in patients who received biologic agents preoperatively. Methods This retrospective observational study was performed in a single tertiary medical center. We retrospectively reviewed patients who underwent the first major abdominal surgery due to Crohn’s disease and divided them into two groups: biologics users both in the preoperative and postoperative periods and biologics users only in the preoperative period. We compared data between the groups according to endoscopic, clinical, and surgical recurrences. Results In total, 49 patients who used biologic agents preoperatively were recruited. Among them, biologics were used postoperatively in 24 patients (49.0%, Figure 1). Baseline characteristics except the median age and age at diagnosis were similar in both groups. Kaplan–Meier analysis revealed that the cumulative clinical recurrence rate was significantly lower in the postoperative biologics group (log-rank 0.012, Figure 2). On multivariate Cox regression analysis, postoperative biologics use was significantly associated with a decreased risk of clinical recurrence (adjusted hazard ratio 0.160, 95% confidence interval 0.037–0.692, p = 0.014). Conclusion Continuing biologics use postoperatively in patients who were receiving biologics preoperatively significantly reduced the rate of clinical recurrence. For patients with Crohn’s disease who were receiving biologic agents before surgery, continuing their use after surgery is recommended.

We aimed to evaluate whether obesity was associated with a certain clinicopathologic characteristics of metachronous CRA. This retrospective longitudinal cohort study included 2,904 subjects who had at least one resected CRA at index colonoscopy and who subsequently underwent one or more surveillance colonoscopies within 5 years. Of the 2,904 subjects, 60.9% (n = 1,769) were normal, 35.8% (n = 1,040) were overweight, and 3.3% (n = 95) were obese. Patients with any metachronous CRA were 53.7% (n = 1,559). In multivariate analyses, higher BMI at index colonoscopy was significantly associated with any metachronous CRA (overweight, OR = 1.07; obese, OR = 1.82; p for trend = 0.049). Regarding the multiplicity, the ORs of ≥ 3, ≥ 4 and ≥ 5 metachronous CRAs significantly increased as index BMI increased (p for trend p for trend = 0.016). Higher index BMI was significantly associated with the risk of multiple metachronous CRAs on surveillance colonoscopy within 5 years.

Background/Aims We aimed to estimate the cumulative incidence of advanced colonic neoplasia and analyze the risk factors for advanced colonic neoplasia according to risk components and adenoma location at index colonoscopy. Methods We reviewed 1,974 subjects who underwent a follow-up colonoscopy after a complete screening colonoscopy and the removal of all polyps. We estimated the cumulative incidence of a subsequent advanced neoplasia according to risk groups (normal, low-risk, and high-risk). Risk factors were analyzed by risk components (≥3 adenomas, adenoma ≥1 cm, and villous-type adenoma) and adenoma location. Results Overall, 111 advanced neoplasias (5.6%) were newly diagnosed at the follow-up colonoscopy. The 3-year cumulative incidences of advanced neoplasia were 0.8%, 3.1%, and 10.2% in the normal, low-risk, and high-risk groups, respectively (p

A wheel drive mechanism is simple, stable, and efficient, but its mobility in unstructured terrain is seriously limited. Using a deformable wheel is one of the ways to increase the mobility of a wheel drive robot. By changing the radius of its wheels, the robot becomes able to pass over not only high steps but also narrow gaps. In this article, we propose a novel design for a variable-diameter wheel using an origami-based soft robotics design approach. By simply folding a patterned sheet into a wheel shape, a variable-diameter wheel was built without requiring lots of mechanical parts and a complex assembly process. The wheel's diameter can change from 30 to 68 mm, and it is light in weight at about 9.7 g. Although composed of soft materials (fabrics and films), the wheel can bear more than 400 times its weight. The robot was able to change the wheel's radius in response to terrain conditions, allowing it to pass over a 50-mm gap when the wheel is shrunk and a 50-mm step when the wheel is enlarged.

Background and Aim There is controversy about the surveillance interval after colonoscopy when 5–10 adenomas have been found on index colonoscopy. This study aimed to investigate the risk of colorectal neoplasm (CRN) according to the number of adenomas at index colonoscopy. Methods A retrospective, multicenter study was conducted at 10 university hospitals in Korea. We included 1394 patients with ≥ 3 adenomas at index colonoscopy. The risk of advanced CRN was compared according to the number of adenomas (intermediate risk group, 3–4 small adenomas or at least one ≥ 10 mm, and high risk group, ≥ 5 small adenomas or ≥ 3 at least one ≥ 10 mm). Results Overall, 164 (11.8%) developed an advanced CRN after a mean of 4.0 years from baseline colonoscopy. The 3-year and 5-year risk of advanced CRN was 2.1% (95% CI 2.09–2.11) and 14.4% (95% CI 14.36–14.44) in intermediate risk group and 3.2% (95% CI 3.19–3.21) and 23.3% (95% CI 19.15–19.25) in high risk group (P = 0.01). Having ≥ 5 adenomas (OR = 1.57, 95% CI 1.11–2.23, P = 0.01) detected at index colonoscopy was a significant risk factor for developing advanced CRN. Conclusions Although risk of advanced CRN in patients with 5–10 adenomas was significantly higher than that in patients with 3–4 adenomas, the cumulative risk at 3 years was low at 3.2%. Thus, we suggest that a 3-year surveillance interval might be appropriate for the patients with 5–10 adenomas, and further prospective studies are needed to investigate whether more intensive surveillance is needed in this group.

Summary of Event A 65-year-old women underwent endoscopic ultrasonography (EUS) to evaluate the gastric submucosal tumor. The EUS scope was inserted into the esophagus after two attempts. A neck computed tomography (CT) scan showed a pneumomediastinum and an air bubble deep in the neck, suggesting an esophageal rupture. The patient was hospitalized and maintained conservative treatment including broad-spectrum antibiotics and withholding oral feeding. Teaching Point Endoscopists should consider an imaging modality when a patient complains of moderate to severe neck pain after an upper endoscopy. Prompt surgical management should be considered in patients with a delayed diagnosis (> 24 hours), those with signs of systemic toxicity, and those who have eaten between the time of the procedure and when the perforation was detected.

Sarcopenia is defined as skeletal muscle attenuation and has an association with metabolic syndrome. Metabolic syndrome, which includes obesity, is one of known predictive factors for gastroesophageal reflux disease (GERD). This study aimed to elucidate the association between sarcopenia and GERD. We retrospectively reviewed electronic medical records of 8,218 patients who were performed an upper gastrointestinal endoscopy at check-up center of the Gangnam Severance Hospital. GERD was diagnosed by endoscopic findings. Erosive reflux disease (ERD) included Barrett's esophagus and reflux esophagitis, with the exception of minimal change esophagitis. Sarcopenia was defined by appendicular skeletal muscle (skeletal muscle in the upper and lower limbs). Sarcopenic obesity was defined as the presence of both sarcopenia and obesity. Associations between sarcopenia and GERD, as well as between sarcopenic obesity and ERD, were analyzed. A total of 3,414 patients were diagnosed with GERD, and 574 (16.8%) had sarcopenia. Sarcopenia was independent predictive factor for GERD (odds ratio [OR] = 1.170, 95% confidence interval [CI]: 1.016–1.346, P = 0.029). In addition, male sex, smoking, alcohol, and diet, including sweets and fatty food, had a significant association with GERD. A total of 1,423 (17.3%) of 8,218 patients were diagnosed with ERD, and 302 (21.2%) had sarcopenia. Male sex, smoking, and fatty food consumption had a significant association with ERD. Moreover, sarcopenia (OR = 1.215, 95% CI: 1.019–1.449, P = 0.030), obesity (OR = 1.343, 95% CI: 1.163–1.552, P P

Supplemental Digital Content is available in the text, The potential relationship between coronary artery calcium (CAC) and colorectal adenoma has been widely indicated. This study aimed to investigate the relationship between the risk of colorectal adenoma and CAC progression in asymptomatic Korean adults who underwent serial assessments by colonoscopy and CAC scan. A total of 754 asymptomatic participants, who had undergone serial CAC scans and colonoscopies for screening, were enrolled. Changes in CAC were assessed according to the absolute change between baseline and follow-up results. CAC progression was defined using Multi-Ethnic Study of Atherosclerosis method. Risk for adenoma at follow-up colonoscopy was determined using hazard ratio (HR) by Cox regression. The area under the receiver operating characteristic (ROC) curve was measured. The mean follow-up duration was 3.4 ± 2.5 years. CAC progression was found in 215 participants (28.5%). Participants with adenoma at index colonoscopy showed a higher rate of CAC progression than those without (38.8% vs 23.6%, P

Background and aim We conducted a nationwide validation study of diagnostic algorithms to identify cases of inflammatory bowel disease (IBD) within the Korea National Health Insurance System (NHIS) database. Method Using the NHIS dataset, we developed 44 algorithms combining the International Classification of Diseases (ICD)-10 codes, codes for Rare and Intractable Diseases (RID) registration and claims data for health care encounters, and pharmaceutical prescriptions for IBD-specific drugs. For each algorithm, we compared the case identification results from electronic medical records data with the gold standard (chart-based diagnosis). A multiple sampling test verified the validation results from the entire study population. Results A random nationwide sample of 1697 patients (848 potential cases and 849 negative control cases) from 17 hospitals were included for validation. A combination of the ICD-10 code, ≥ 1 claims for health care encounters, and ≥ 1 prescription claims (reference algorithm) achieved excellent performance (sensitivity, 93.1% [95% confidence interval 91-94.7]; specificity, 98.1% [96.9-98.8]; positive predictive value, 97.5% [96.1-98.5]; negative predictive value, 94.5% [92.8-95.8]) with the lowest error rate (4.2% [3.3-5.3]). The multiple sampling test confirmed that the reference algorithm achieves the best performance regarding IBD diagnosis. Algorithms including the RID registration codes exhibited poorer performance compared with that of the reference algorithm, particularly for the diagnosis of patients affiliated with secondary hospitals. The performance of the reference algorithm showed no statistical difference depending on the hospital volume or IBD type, with P-value Conclusions We strongly recommend the reference algorithm as a uniform standard operational definition for future studies using the NHIS database.

Background: Sarcopenia, defined as skeletal muscle loss, has been known as a poor prognosis factor in various malignant diseases The aim of this study is to investigate the effect of sarcopenia on prognosis in patients with esophageal cancer who received concurrent chemo- and radiotherapy (CCRT).Methods: We retrospectively collected clinical data of 287 patients with esophageal cancer who were treated by definite CCRT at Gangnam Severance and Severance hospital from August 2005 to December 2014. The cross-sectional area of muscle at the level of the third lumbar vertebra was measured using pre- and post-CCRT computed tomography images. Sarcopenia was defined as skeletal muscle index

Background Therapeutic options for inflammatory bowel disease (IBD) have increased since the introduction of tumour necrosis factor (TNF) inhibitors a few decades ago. However, direct comparisons of the effectiveness of second-line biological agents in patients with ulcerative colitis (UC) and Crohn’s disease (CD) are lacking. Methods Patients with UC or CD who experienced anti-TNF treatment failure and subsequently used vedolizumab, ustekinumab, or tofacitinib as a second-line drug were retrospectively recruited. The primary outcomes were the clinical remission rate at week 16 and the cumulative relapse rate 48 weeks after receiving induction therapy. Results A total of 94 patients with UC or CD experienced anti-TNF treatment failure and received vedolizumab (UC : 37; CD : 28), ustekinumab (CD : 16), or tofacitinib (UC : 13). The clinical remission rates were not significantly different between the vedolizumab and tofacitinib groups in UC patients (56.8% vs. 46.2%, p = 0.509). In CD patients, the clinical remission rates were not significantly different between the vedolizumab and ustekinumab groups (53.6% vs. 50.0%, p = 0.820). Moreover, the cumulative rates of clinical relapse were not significantly different between the vedolizumab and tofacitinib groups in UC patients and between the vedolizumab and ustekinumab groups in CD patients (p = 0.396 and p = 0.692, respectively). Safety profiles were also similar among the treatment groups in both UC and CD patients. Conclusion After prior anti-TNF therapy failure, vedolizumab and tofacitinib in UC patients and vedolizumab and ustekinumab in CD patients showed similarities in terms of the efficacy in inducing and maintaining a clinical response.

Capsule endoscopy (CE) enables evaluation of the entire mucosal surface of the small bowel (SB), which is one of the most important steps for evaluating obscure gastrointestinal bleeding. Although the diagnostic yield of SB CE depends on many clinical factors, there are no reports on quality indicators. Thus, the Korean Gut Image Study Group (KGISG) publishes an article titled, "Quality Indicators for Small Bowel Capsule Endoscopy" under approval from the Korean Society of Gastrointestinal Endoscopy (KSGE). Herein, we initially identified process quality indicators, while the structural and outcome indicators are reserved until sufficient clinical data are accumulated. We believe that outcomes of SB CE can be improved by trying to meet our proposed quality indicators.

Inverter surge resistant enameled wire was prepared with an organic/inorganic hybrid nanocomposite, and the effect of ambient temperature on the insulation lifetime of the enameled wire in the form of twisted pair was studied by a withstanding voltage tester. The organic polymer was Polyesterimide-polyamideimide (EI/AI) and the inorganic material was a Nano-sized silica (average particle size : 15 nm). The enamel thickness was 50 μm and the ambient temperature was 100℃, 150℃, 200℃, and 250℃, respectively. Transmission electron microscopy (TEM) observation showed that Nano-sized Silica were evenly dispersed in EI/AI. There were many air gaps in a twisted pair, therefore, when voltage was applied to the twisted pair, enamel erosion took place in the air gap area because of partial discharge accordi, ng to Paschen's law. As ambient temperature increased, insulation lifetime decreased according to Arrhenius relationship, which was explained by the increasing mobility of polymer chains in EI or AI. And insulation breakdown voltage value at 10 kHz was 1,864.5 sec (31.1 min), which is 1.9 times higher than at 20 kHz, 981.6 sec (16.4 min).

Background/aims A limited number of studies are available regarding the long-term natural history of post-infectious irritable bowel syndrome (PI-IBS). We aimed to investigate the long-term clinical course of PI-IBS. Methods A prospective cohort study was conducted from a 2001 shigellosis outbreak in a Korean hospital with about 2000 employees. A cohort of 124 hospital employees who were infected by Shigella sonnei due to contaminated food in the cafeteria, and 105 sex- and age-matched, non-infected, controls were serially followed for their bowel symptoms by questionnaire surveys for 10 years. Results The Shigella -infected cohort showed significantly higher odds ratio for irritable bowel syndrome (IBS) at 1-year (11.90; 95% CI, 1.49-95.58) and 3-year (3.93; 95% CI, 1.20-12.86) follow-up, compared to their controls. However, corresponding odds ratio for PI-IBS was not significantly increased at 5-year (1.88; 95% CI, 0.64-5.54) and 8-year (1.87; 95% CI, 0.62-5.19) follow-up. At 10-year follow-up survey, the prevalence of IBS was similar for the Shigella -infected cohort and their controls (23.3% versus 19.7%, P = 0.703). Risk factors which were independently associated with PI-IBS among the Shigella -infected cohort included younger age, previous history of functional bowel disorder, and longer duration of diarrhea at baseline. Conclusions Patients who were infected by Shigella sonnei experienced significantly increased risk of IBS until 3 years after shigellosis, and modestly increased risk until 8 years, but showed similar risk of IBS with uninfected controls at 10 years post-infection. PI-IBS is quite a chronic disorder, and follows a long-term natural course.

Low-volume polyethylene glycol (PEG) plus ascorbic acid solutions are widely used for bowel cleansing before colonoscopy. This study aimed to investigate the pre-endoscopic predictive factors for inadequate preparation in subjects receiving low-volume PEG plus ascorbic acid. A prospective study was performed at Gangnam Severance Hospital, Korea, from June 2016 to December 2016. All participants received low-volume PEG plus ascorbic acid solutions for outpatient colonoscopy. The split-dose bowel preparation was administered in subject with morning colonoscopy while same day bowel preparation was used for afternoon colonoscopy. 715 patients were enrolled (mean age 56.1 years, 54.4% male), of which 138 (19.3%) had an inadequate bowel preparation. In multivariable analysis, cirrhosis (OR 4.943, 95% CI 1.191–20.515), low (less than 70%) compliance for three-day low-residual diet (OR 2.165, 95% CI 1.333–3.515), brown liquid rectal effluent (compared with clear or semi-clear effluent) (OR 7.604, 95% CI, 1.760–32.857), and longer time interval (≥2 hours) between last defecation and colonoscopic examination (OR 1.841, 95% CI, 1.190–2.849) were found as an independent predictors for inadequate preparation. These predictive factors may be useful in guiding additional intervention to improve quality of bowel preparation.

Background & Aims Thiopurine-related myelosuppression (most frequently leukopenia) interferes with thiopurine therapy for patients with inflammatory bowel diseases (IBD). We investigated whether pretreatment analyses genetic variants associated with thiopurine-induced leukopenia could be used to effectively identify patients who required dose adjustments. Methods We performed a multicenter, prospective study of patients with IBD at 5 tertiary medical centers in Korea, from January 2016 through September 2018. Seventy-two patients were randomly assigned to a group that underwent genotype analysis for the NUDT15 variant (rs116855232) and FTO variant (rs79206939) and 3 common TPMT variants (rs1800460, rs1800462, rs1142345) associated with myelosuppression and 92 patients were assigned to a group that did not undergo genotype analysis (non-genotyping group). Patients heterozygous for any variant received 50 mg azathioprine equivalents, whereas those who were homozygous for any variant received alternative drugs. Patients who did not carry any of the genetic variants and patients in the non-genotyping group received 50 mg azathioprine equivalents followed by dose escalation up to 2–2.5 mg/kg. Myelosuppression was defined as white blood cell counts below 3000/μL, levels of hemoglobin 10 g/dL, or platelet counts below 100 K/μL. Results Twelve patients (16.7%) in the genotype analysis group and 33 patients (35.9%) in the non-genotyping group developed myelosuppression (P=.005). A multivariate analysis revealed that body mass indices above 21 kg/m2 (hazard ratio [HR], 0.43; 95% CI, 0.22–0.81; P = .009), pretreatment genotype analysis (HR, 0.37; 95% CI, 0.18–0.77; P = .008), and the maximum dose of thiopurines (HR, 0.34; 95% CI, 0.19–0.59; P Conclusions In a randomized controlled study of patients undergoing thiopurine therapy for IBD, we found that selection of therapy based on genetic variants associated with thiopurine-induced leukopenia significantly reduced the proportion of patients with myelosuppression during treatment. ClinicalTrials.gov no: NCT03719118 .

The most concerning complication of capsule endoscopy (CE) is capsule retention (CR) in the gastrointestinal (GI) tract; however, the clinical outcomes and management of patients with CR are still uncertain. This study aimed to investigate the clinical outcomes and management of CR. The outcomes of CR in multiple centers between October 2002 and June 2018 were retrospectively reviewed. Data on CE indication, findings, and management details were analyzed. A total of 2705 consecutive small-bowel CE procedures were performed. CR was detected in 20 cases (0.7%). The most common site of CR was the small bowel (19 cases), followed by the esophagus (one case). In patients who underwent CE, CR was detected in nine (0.6%) of 1397 patients with obscure GI bleeding. Further, CR occurred in 11 (6.5%) of 169 patients with Crohn’s disease based on the final diagnoses after CE. Capsule retrieval was safely performed surgically in nine cases and endoscopically in six cases. The retained capsules dislodged after steroid treatment in two cases, whereas three cases of CR resolved without any intervention. In multivariate analysis, the development of abdominal symptoms after CR was a significant predictive factor for requiring endoscopic or surgical interventions for capsule extraction. This large multicenter study shows that CR is a rare complication with favorable clinical outcomes. Three-fourths of the patients with CR were managed with endoscopic or surgical intervention, which was required particularly in patients with abdominal symptoms after CR.

Background and purpose Based on the 6th edition of the American Joint Commission on Cancer (AJCC) staging system for esophageal squamous cell carcinoma (ESCC), M1a node involvement was classified as regional node involvement in the revised 7th/8th edition. However, the clinical significance of M1a node involvement is unclear. Thus, we analyzed the prognostic value of M1a node involvement in patients with ESCC after definitive concurrent chemoradiotherapy (CCRT). Materials and methods In total, 188 patients with ESCC had M0 disease according to the 7th/8th edition AJCC. We reclassified 31 (16.5%) of these patients as having M1a disease according to the 6th edition. After definitive CCRT, we compared baseline characteristics between the two groups and analyzed the rates of responders and recurrence. Finally, we compared prognoses according to overall survival (OS), disease-specific OS, and disease-free survival (DFS). Results Among 31 patients reclassified to have M1a disease, 21 (67.7%) had supraclavicular lymph node metastasis and 10 (32.3%) had celiac lymph node metastasis. The number of responders was significantly lower for M1a disease based on univariate (p = 0.004) and multivariate (p = 0.011) analyses. Significantly lower survival rates were observed in individuals with M1a disease (median OS, 16.4 vs. 42.7 months; 5-year OS, 10.8% vs. 41.2%). Conclusions M1a node involvement should be differentiated from regional node involvement.

Background Thiopurine-related myelosuppression (most frequently leukopenia) interferes with thiopurine therapy for patients with inflammatory bowel diseases (IBD). We investigated whether pre-treatment analyses genetic variants associated with thiopurine-induced leukopenia could be used to effectively identify patients who required dose adjustments. Methods We performed a multicentre, prospective study of patients with IBD at 5 tertiary medical centres in Korea, from January 2016 through September 2018. Seventy-two patients were randomly assigned to a group that underwent genotype analysis for the NUDT15 variant (rs116855232) and FTO variant (rs79206939) and 3 common TPMT variants (rs1800460, rs1800462, rs1142345) associated with myelosuppression and 92 patients were assigned to a group that did not undergo genotype analysis (non-genotyping group). Patients heterozygous for any variant received 50 mg azathioprine equivalents, whereas those who were homozygous for any variant received alternative drugs. Patients who did not carry any of the genetic variants and patients in the non-genotyping group received 50 mg azathioprine equivalents followed by dose escalation up to 2–2.5 mg/kg. Myelosuppression was defined as white blood cell counts below 3000/μL, levels of haemoglobin 10 g/dl, or platelet counts below 100 K/μl. Results Twelve patients (16.7%) in the genotype analysis group and 33 patients (35.9%) in the non-genotyping group developed myelosuppression (p = .005). A multivariate analysis revealed that body mass indices above 21 kg/m2 (hazard ratio [HR], 0.43; 95% CI, 0.22–0.81; p = 0.009), pre-treatment genotype analysis (HR, 0.37; 95% CI, 0.18–0.77; p = 0.008), and the maximum dose of thiopurines (HR, 0.34; 95% CI, 0.19–0.59; p < 0.001) independently decreased risk of myelosuppression. Pre-treatment genotype analysis reduced numbers of outpatient clinic visit and numbers of patients with drug discontinuation or dose reductions. Conclusion In a randomised controlled study of patients undergoing thiopurine therapy for IBD, we found that selection of therapy based on genetic variants associated with thiopurine-induced leucopoenia significantly reduced the proportion of patients with myelosuppression during treatment.