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Competing Interests: Disclosure The following authors disclosed financial relationships: D. K. Rex: Consultant for Olympus Corporation, Boston Scientific, Braintree Laboratories, Norgine, GI Supply, Medtronic, and Acacia Pharmaceuticals; research support from Olympus Corporation, Medivators, Erbe USA Inc, and Braintree Laboratories; shareholder in Satisfai Health. T. Kaltenbach: Consultant for Verily Life Sciences and Olympus Corporation. U. Ladabaum: Advisor for Universal Dx, Kohler Ventures, Vivante Health, and Lean Health; consultant for Freenome, Guardant, Neptune, Media EarlySign, and Medtronic. T. R. Levin: Research support from Freenome, Inc. A. Shaukat: Consultant for Iterative Health. F. A. Farraye: Consultant for AbbVie, Avalo Therapeutics, BMS, Braintree Labs, Fresenius Kabi, GI Reviewers, GSK, IBD Educational Group, Iterative Health, Janssen, Pharmacosmos, Pfizer, Sandoz Immunology, and Viatris; data and safety monitoring board for Lilly. S. Kane: Consultant for Boehringer Ingelheim, Bristol Meyers Squibb, InveniAI, Janssen, Fresenius Kabi, PredicatMed, Lilly, and Takeda; section editor for UpToDate. All other authors disclosed no financial relationships.

Background: Postoperative recurrence of Crohn's disease (CD) is common. While most patients undergo resection with undiverted anastomosis (UA), some individuals also have creation of an intended temporary diversion (ITD) with an ileostomy followed by ostomy takedown (OT) due to increased risk of anastomotic complications. We assessed the association of diversion with subsequent CD recurrence risk and the influence of biologic prophylaxis timing to prevent recurrence in this population., Methods: This was a retrospective cohort study of CD patients who underwent ileocolic resection between 2009 and 2020 at a large quaternary health system. Patients were grouped by continuity status after index resection (primary anastomosis or ITD). The outcomes of the study were radiographic, endoscopic, and surgical recurrence as well as composite recurrence postoperatively (after OT in the ITD group). Propensity score-weighted matching was performed based on risk factors for diversion and recurrence. Multivariable regression and a Cox proportional hazards model adjusting for recurrence risk factors were used to assess association with outcomes. Subgroup analysis in the ITD group was performed to assess the impact of biologic timing relative to OT (no biologic, biologic before OT, after OT) on composite recurrence., Results: A total of 793 CD patients were included (mean age 38 years, body mass index 23.7 kg/m2, 52% female, 23% active smoker, 50% penetrating disease). Primary anastomosis was performed in 67.5% (n = 535) and ITD in 32.5% (n = 258; 79% loop, 21% end) of patients. Diverted patients were more likely to have been males and to have had penetrating and perianal disease, prior biologic use, lower body mass index, and lower preoperative hemoglobin and albumin (all P < .01). After a median follow-up of 44 months, postoperative recurrence was identified in 83.3% patients (radiographic 40.4%, endoscopic 39.5%, surgical 13.3%). After propensity score matching and adjusting for recurrence risk factors, no significant differences were seen between continuity groups in radiographic (adjusted hazard ratio [aHR], 1.32; 95% confidence interval [CI], 0.91-1.91) or endoscopic recurrence (aHR, 1.196; 95% CI, 0.84-1.73), but an increased risk of surgical recurrence was noted in the ITD group (aHR, 1.61; 95% CI, 1.02-2.54). Most (56.1%) ITD patients started biologic prophylaxis after OT, 11.4% before OT, and 32.4% had no postoperative biologic prophylaxis. Biologic prophylaxis in ITD was associated with younger age (P < .001), perianal disease (P = .04), and prior biologic use (P < .001) but not in recurrence (P = .12). Despite higher rates of objective disease activity identified before OT, biologic exposure before OT was not associated with a significant reduction in composite post-OT recurrence compared with starting a biologic after OT (52% vs 70.7%; P = 0.09)., Conclusions: Diversion of an ileocolic resection is not consistently associated with a risk of postoperative recurrence and should be performed when clinically appropriate. Patients requiring diversion at time of ileocolic resection are at high risk for recurrence, and biologic initiation prior to stoma reversal may be considered., (© The Author(s) 2024. Published by Oxford University Press on behalf of Crohn’s & Colitis Foundation. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Since its release in 2022, Chat Generative Pre-Trained Transformer (ChatGPT) became the most rapidly expanding consumer software application in history, 1 and its role in medicine is underscored by its potential to enhance patient education and physician-patient communication. Previous studies in gastroenterology and hepatology have focused primarily on the earlier Generative Pre-Trained Transformer 3 (GPT-3) model, with none investigating ChatGPT's ability to generate supportive references for its responses, or its applicability as a physician educational tool. 2-6 Our study evaluated the accuracy of the more recent ChatGPT, powered by GPT-4, in addressing frequently asked questions by patients on irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), colonoscopy and colorectal cancer (CRC) screening, questions on CRC screening from a physician perspective, and reference generation and suitability., (Copyright © 2024 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Studies report favorable efficacy and safety profiles of ustekinumab (UST) and vedolizumab (VDZ) in Crohn's disease (CD), but effectiveness and safety data in elderly patients with CD is lacking. We retrospectively analyzed 78 elderly patients (39 each UST and VDZ) and found that patients on UST and VDZ experienced similar rates of clinical response, remission and mucosal healing despite high proportion of prior biologic exposure. Both UST and VDZ appear to be effective and safe in this at-risk CD population. Further large studies are needed to validate our findings., (© 2023. Indian Society of Gastroenterology.)

Introduction: Patients with ulcerative colitis (UC) who are likely to have primary sclerosing cholangitis (PSC) should be identified because PSC can influence UC clinical behavior and outcomes.The aim of this study was to establish a model incorporating clinical and genetic risk predictors that identifies patients with UC at risk of developing PSC., Methods: We conducted a retrospective case-control study. Inflammatory bowel disease cohorts from multiple institutions were used as discovery and replicate datasets. Quality control criteria, including minor allele frequency, call rates, Hardy-Weinberg equilibrium, cryptic relatedness, and population stratification (through principal components), were used. Discriminative accuracy was evaluated with area under the receiver operating characteristic curve., Results: Fifty-seven of 581 patients (9.8%) with UC had PSC. Multivariate analysis showed that patients with UC-PSC had more extensive disease (odds ratio [OR], 5.42; P = 1.57E-04), younger diagnosis age (younger than 20 years; OR, 2.22; P = 0.02), and less smoking (OR, 0.42; P = 0.02) than those with UC. After linkage disequilibrium pruning and multivariate analyses, 3 SNPs (rs3131621 at 6p21.33; rs9275596 and rs11244 at 6p21.32) at the HLA region were found associated with a 2- to 3-fold increased risk of PSC. Our model demonstrated good discriminatory power (area under the receiver operating characteristic curve, 88%)., Discussion: Three variants in HLA (6p21.3) region significantly distinguished patients with UC-PSC from patients with UC alone. Once further validated in an independent large cohort, our model could be used to identify patients with UC at risk of PSC, and it could also help guide disease management., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.)

Pyoderma gangrenosum (PG) is a debilitating skin condition often accompanied by inflammatory bowel disease (IBD). Strikingly, ~40% of patients that present with PG have underlying IBD, suggesting shared but unknown mechanisms of pathogenesis. Impeding the development of effective treatments for PG is the absence of an animal model that exhibits features of both skin and gut manifestations. This study describes the development of the first experimental drug-induced mouse model of PG with concomitant intestinal inflammation. Topical application of pyrimidine synthesis inhibitors on wounded mouse skin generates skin ulcers enriched in neutrophil extracellular traps (NETs) as well as pro-inflammatory cellular and soluble mediators mimicking human PG. The mice also develop spontaneous intestinal inflammation demonstrated by histologic damage. Further investigations revealed increased circulating low density IL-1β primed neutrophils that undergo enhanced NETosis at inflamed tissue sites supported by an increase in circulatory citrullinated histone 3, a marker of aberrant NET formation. Granulocyte depletion dampens the intestinal inflammation in this model, further supporting the notion that granulocytes contribute to the skin-gut crosstalk in PG mice. We anticipate that this novel murine PG model will enable researchers to probe common disease mechanisms and identify more effective targets for treatment for PG patients with IBD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Jatana, Ponti, Johnson, Rebert, Smith, Fulmer, Maytin, Achkar, Fernandez and McDonald.)

Background: Approximately 30% of Crohn's disease-related perianal fistulas heal in the adult population with conventional medical and surgical interventions. This healing rate remains unknown in pediatric patients., Objective: This study aimed to determine the healing rate of pediatric perianal Crohn's fistulas and identify factors associated with healing., Design: Retrospective case series., Setting: A quaternary referral center., Patients: Patients aged <18 years with a Crohn's perianal fistula, seen between January 1, 1991, and August 1, 2021, were included in the study., Interventions: Multivariable logistic regression to identify factors independently associated with perianal fistula healing., Main Outcome Measures: Healing of Crohn's perianal fistula at the date of last clinical encounter, defined as the clinical note reporting a healed fistula or normal perianal examination., Results: A total of 91 patients aged <18 years with a Crohn's disease-related perianal fistula were identified (59% female, 76% white). The mean (SD) age at Crohn's diagnosis was 12 (±4) years. The mean follow-up after Crohn's diagnosis was 10 (±7) years. Overall, 89% of patients had a perianal fistula, 2% had an anovaginal fistula, and 10% had an ileal pouch-associated fistula. Patients underwent a median (interquartile range) of 2 (1-5) operations. A seton was placed in 60% of patients, 47% underwent abscess drainage, and 44% underwent fistulotomy or fistulectomy. Fistula healing occurred in 71% of patients over a median of 1.3 (0.4-2.5) years. Seven patients (7%) underwent proctectomy, and 3 (3%) underwent ileal pouch excision. After multivariable adjustment, younger age at diagnosis of perianal fistula was associated with an increased likelihood of healing (OR 0.56 for each increased year; 95% CI, 0.34-0.92)., Limitations: Retrospective, single institution., Conclusions: Over two-thirds of fistulas heal in pediatric Crohn's disease patients with conventional surgical and medical intervention. Younger age at fistula development is associated with an increased likelihood of healing. See Video Abstract at http://links.lww.com/DCR/C185 ., Resultados a Largo Plazo De Las Fstulas Perianales En La Enfermedad De Crohn En Pacientes Peditricos: ANTECEDENTES:Aproximadamente el 30% de las fístulas perianales relacionadas con la enfermedad de Crohn se curan en la población adulta con intervenciones médicas y quirúrgicas convencionales. Esta tasa de curación sigue siendo desconocida en pacientes pediátricos.OBJETIVO:Determinar la tasa de curación de las fístulas de Crohn perianales en población pediátrica e identificar los factores asociados con la curación.DISEÑO:Serie de casos retrospectiva.ESCENARIO:Un centro de referencia cuaternario.PACIENTES:Pacientes menores de 18 años con fístula(s) perianal(es) por enfermedad de Crohn, atendidos entre el 1 de enero de 1991 y el 1 de agosto de 2021.INTERVENCIONES:Regresión logística multivariable para identificar factores asociados de forma independiente con la cicatrización de la fístula perianal.PRINCIPALES MEDIDAS DE RESULTADO:Curación de la fístula perianal de Crohn en la fecha del último encuentro clínico, definida como la nota clínica que informa una fístula curada o un examen perianal normal.RESULTADOS:Se identificó un total de 91 pacientes <18 años de edad con una fístula perianal relacionada con la enfermedad de Crohn (59% mujeres, 76% blancos). La edad media (DE) al diagnóstico de Crohn fue de 12 (±4) años. El seguimiento medio tras el diagnóstico de Crohn fue de 10 (±7) años. En general, el 89 % de los pacientes tenía fístula perianal, el 2 % tenía fístula anovaginal y el 10 % de los pacientes tenía fístula asociada a reservorio ileal. Los pacientes fueron sometidos a una mediana (RIC) de 2 (1-5) operaciones. En el 60% de los pacientes se colocó sedal, en el 47% se drenó el absceso y en el 44% se realizó fistulotomía o fistulectomía. La curación de la fístula se produjo en el 71% de los pacientes durante una mediana de 1,3 (0,4-2,5) años. Siete pacientes (7%) se sometieron a proctectomía y 3 (3%) se sometieron a escisión del reservorio ileal. Después del ajuste multivariable, la edad más joven en el momento del diagnóstico de la fístula perianal se asoció con una mayor probabilidad de curación (OR 0,56 por cada año de aumento, IC del 95%, 0,34-0,92).LIMITACIONES:Retrospectivo, institución única.CONCLUSIONES:Más de dos tercios de las fístulas se curan en pacientes pediátricos con enfermedad de Crohn con intervención médica y quirúrgica convencional. Una edad más joven en el momento del desarrollo de la fístula se asocia con una mayor probabilidad de curación. Consulte Video Resumen en http://links.lww.com/DCR/C185 . (Traducción--Dr. Felipe Bellolio )., (Copyright © The ASCRS 2023.)

Background: Postoperative recurrence [POR] of Crohn's disease following ileocolonic resection is common. The impact of immediate postoperative intra-abdominal septic complications [IASC] on endoscopic and surgical recurrence has not been elucidated., Aims: To evaluate if IASC is associated with an increased risk for endoscopic and surgical POR., Methods: This was a retrospective study of adult Crohn's disease patients undergoing ileocolonic resection with primary anastomosis between 2009 and 2020. IASC was defined as anastomotic leak or intra-abdominal abscess within 90 days of the date of surgery. Multivariable logistic and Cox proportional hazard modelling were performed to assess the impact of IASC on endoscopic POR [modified Rutgeerts' score ≥ i2b] at index postoperative ileocolonoscopy and long-term surgical recurrence., Results: In 535 Crohn's disease patients [median age 35 years, 22.1% active smokers, 35.7% one or more prior resection] had an ileocolonic resection with primary anastomosis. A minority of patients [N = 47; 8.8%] developed postoperative IASC. In total, 422 [78.9%] patients had one or more postoperative ileocolonoscopies, of whom 163 [38.6%] developed endoscopic POR. After adjusting for other risk factors for postoperative recurrence, postoperative IASC was associated with significantly greater odds (adjusted odds ratio [aOR]: 2.45 [1.23-4.97]; p = 0.01) and decreased time (adjusted hazards ratio [aHR]: 1.60 [1.04-2.45]; p = 0.03] to endoscopic POR. Furthermore, IASC was associated with increased risk (aOR: 2.3 [1.04-4.87] p = 0.03) and decreased survival-free time [aHR: 2.53 [1.31-4.87]; p = 0.006] for surgical recurrence., Conclusion: IASC is associated with an increased risk for endoscopic and surgical POR of Crohn's disease. Preoperative optimization to prevent IASC, in addition to postoperative biological prophylaxis, may help reduce the risk for endoscopic and surgical POR., (© The Author(s) 2022. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Analytic tools to study important clinical issues in complex, chronic diseases such as Crohn's disease (CD) include randomized trials, claims database studies, or small longitudinal epidemiologic cohorts. Using natural language processing (NLP), we sought to define the computable phenotype health state of pediatric and adult CD and develop patient-level longitudinal histories for health outcomes., Methods: We defined 6 health states for CD using a subjective symptom-based assessment (symptomatic/asymptomatic) and an objective disease state assessment (active/inactive/no testing). Gold standard for the 6 health states was derived using an iterative process during review by our CD experts. We calculated the transition probabilities to estimate the time to transitions between the various health states using nonparametric Kaplan-Meier estimation and a Markov model. Finally, we determined a standard utility measure from clinical patients assigned to different health states., Results: The NLP computable phenotype health state model correctly ascertained the objective test results and symptoms 96% and 85% of the time, respectively, based on a blinded chart evaluation. In our model, >25% of patients who begin as asymptomatic/active transition to symptomatic/active over the following year. For both adult and pediatric CD health states, the utility assessments of a symptomatic/inactive health state closely resembled a symptomatic/active health state., Conclusions: Our methodology for a computable phenotype health state demonstrates the application of real-world data to define progression and optimal management of a chronic disease such as CD. The application of the model has the potential to lead to a better understanding of the true impact of a therapeutic intervention and can provide long-term cost-effectiveness analyses for a new therapy., Highlights: Using natural language processing, we defined the computable phenotype health state of Crohn's disease and developed patient-level longitudinal histories for health outcomes.Our methodology demonstrates the application of real-world data to define the progression of a chronic disease.The application of the model has the potential to provide better understanding of the true impact of a new therapy.

Background & Aims: Postoperative Crohn's disease (CD) surveillance relies on endoscopic monitoring. The role of cross-sectional imaging is less clear. We evaluated the concordance of cross-sectional enterography with endoscopic recurrence and the predictive ability of radiography for future CD postoperative recurrence., Methods: We performed a multi-institution retrospective cohort study of postoperative adult patients with CD who underwent ileocolonoscopy and cross-sectional enterography within 90 days of each other following ileocecal resection. Imaging studies were interpreted by blinded, expert CD radiologists. Patients were categorized by presence of endoscopic postoperative recurrence (E+) (modified Rutgeerts' score ≥i2b) or radiographic disease activity (R+) and grouped by concordance status., Results: A total of 216 patients with CD with paired ileocolonoscopy and imaging were included. A majority (54.2%) exhibited concordance (34.7% E+/R+; 19.4% E-/R-) between studies. The plurality (41.7%; n = 90) were E-/R+ discordant. Imaging was highly sensitive (89.3%), with low specificity (31.8%), in detecting endoscopic postoperative recurrence. Intestinal wall thickening, luminal narrowing, mural hyper-enhancement, and length of disease on imaging were associated with endoscopic recurrence (all P &lt; .01). Radiographic disease severity was associated with increasing Rutgeerts' score (P &lt; .001). E-/R+ patients experienced more rapid subsequent endoscopic recurrence (hazard ratio, 4.16; P = .033) and increased rates of subsequent endoscopic (43.8% vs 22.7%) and surgical recurrence (20% vs 9.5%) than E-/R- patients (median follow-up, 4.5 years)., Conclusions: Cross-sectional imaging is highly sensitive, but poorly specific, in detecting endoscopic disease activity and postoperative recurrence. Advanced radiographic disease correlates with endoscopic severity. Patients with radiographic activity in the absence of endoscopic recurrence may be at increased risk for future recurrence, and closer monitoring should be considered., (Copyright © 2022 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Introduction: The efficacy and safety profile of ustekinumab (UST) in Crohn's disease (CD) is favorable; however, data in elderly patients are lacking. We aimed to assess the safety and efficacy of UST in elderly CD., Methods: We performed a retrospective cohort study of CD patients classified as elderly (age ≥ 65 years at UST initiation) or nonelderly (<65 years) treated at a large, tertiary referral center. Outcomes assessed were clinical (measured by physician global assessment [PGA]) and steroid-free response, remission, adverse events, and postsurgical complications were compared by age category. Multivariable regression modeling and survival analysis was also performed., Results: In total, 117 patients (elderly n = 39, nonelderly n = 78) were included in the study. Elderly patients had predominantly moderate disease (87.2%), while nonelderly had a higher proportion of severe disease activity (44.9%) (p = 0.001), though no differences in baseline endoscopic activity, prior biologic use, or steroid or immunomodulator use at baseline existed (p > 0.05 all). While nearly 90% patients in both groups experienced clinical response to UST, compared to nonelderly, elderly patients were less likely to achieve complete clinical remission (28.2% vs. 52.6%, p = 0.01). On regression modeling, age was not associated with clinical outcomes (p > 0.05 all). Mucosal healing was achieved in 26% elderly and 30% nonelderly patients (p = 0.74). There were no significant differences in infusion reactions (2.6% vs. 6.4%, p = 0.77), infection (5.2% vs. 7.7%, p = 0.7), or postsurgical complications (p = 0.99) by age category., Conclusion: UST is safe and effective in elderly CD. Although limited by sample size and retrospective design, such real-world data can inform biologic positioning in this IBD population., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

There are conflicting data assessing the impact of isolated post-operative anastomotic inflammation on future disease progression. The aim of this study was to determine the relative risk of severe disease progression in post-operative Crohn's disease (CD) patients with isolated anastomotic disease., Methods: Retrospective cohort study of adult CD patients undergoing ileocolonic resection between 2009 and 2020. Patients with a post-operative ileocolonoscopy ≤18 months from surgery and ≥1 subsequent ileocolonoscopy were included. Disease activity was assessed using the modified Rutgeerts' score (RS). Primary outcome was severe endoscopic progression, defined as i3 or i4 disease, on immediate subsequent ileocolonoscopy and during entire post-operative follow-up. Secondary outcome was surgical recurrence., Results: One hundred and ninety-nine CD patients had an ileocolonoscopy ≤18 months from surgery, index RS of i0-i2b and ≥1 subsequent ileocolonoscopy. At index ileocolonoscopy, 34.7% had i0 disease, 16.1% i1, 24.6% i2a and 24.6% i2b. On multivariable logistic regression, i2b disease was associated with severe endoscopic progression compared to i0 or i1 (aOR 5.53; P < 0.001) and i2a disease patients (aOR 2.63; P = 0.03). However, i2a disease did not confer increased risk compared to i0 or i1 disease (P = 0.09). Furthermore, i2b patients experienced severe endoscopic progression significantly earlier than i0 or i1 disease (aHR 4.68; P < 0.001), whereas i2a disease did not differ from i0 or i1 disease (P = 0.25). Surgical recurrence was not associated with index RS i0-i2b (P = 0.86)., Conclusion: Post-operative ileal disease recurrence, not isolated anastomotic inflammation, confers increased risk for severe endoscopic disease progression. Location of CD recurrence may impact optimal management strategies., (© 2022 John Wiley & Sons Ltd.)

Clinicians may be hesitant to prescribe biologics or immunomodulators to individuals with familial adenomatous polyposis (FAP) and comorbid inflammatory disease (CID) because of increased cancer risk. Our aim was to compare the risk of malignancy in FAP individuals with inflammatory bowel (IBD) and/or rheumatic disease that received biologics/immunomodulators to those who did not. Individuals with FAP and CID were included in the study. We compared the incidence of cancer between individuals exposed to biologics/immunomodulators compared to unexposed from the date of diagnosis of comorbid disease till last follow up or death. Hazard ratio (HR) for cancer was computed using Cox regression model and compared by exposure status to biologic/immunomodulators. 25 individuals with FAP and a comorbid inflammatory disease were identified including 9 (36%) with IBD and 16 (64%) with rheumatic disease. 14 (56%) were exposed to a biologic and or immunomodulator. Median duration of biologic/immunomodulator exposure was 48 (2-180) months. 3 (21.4%) in the exposed group compared to 1 (9.1%) in the unexposed group developed cancer with a HR for exposure of 1.92 (CI 0.2-18.5, p = 0.57). Median duration of follow up after the diagnosis of inflammatory disease was 10 (5.5-17.0) years in the exposed and 6 (3.0-15.0) years in the unexposed group. In the exposed group, 1 patient developed gastric and 2 developed colon cancer. One unexposed patient developed medullary thyroid cancer. There is a possible trend of more cancers in the group that received biologics/immunomodulators-but given the small number of patients and p-value, there may be no difference at all. This preliminary finding warrants study in a larger cohort., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

Introduction: Ileocolic resection for Crohn's disease traditionally does not include a high ligation of the ileocolic pedicle, and most commonly is performed with a stapled side-to-side ileocolic anastomosis. The mesentery has recently been implicated in the pathophysiology of Crohn's disease. Two techniques have been developed and are associated with reduced postoperative recurrence: the Kono-S anastomosis that excludes diseased mesentery and extended mesenteric excision that resects diseased mesentery. We aimed to assess the technical feasibility and safety of a novel combination of techniques: mesenteric excision and exclusion., Techniques: This initial report is a single-center descriptive study of consecutive adults who underwent mesenteric excision and exclusion for primary or recurrent ileocolic Crohn's disease from September 2020 to June 2021. Medication exposure and endoscopic balloon dilation before surgery were recorded. Phenotype was classified using the Montreal Classification. Thirty-day outcomes were reported. A video of the mesenteric excision and exclusion including the Kono-S anastomosis is presented., Results: Twenty-two patients with ileocolic Crohn's disease underwent mesenteric excision and exclusion: 100% had strictures, 59% had fistulas, 81% were on biologics, and 27% had previous ileocolic resection(s). Seventy-two percent underwent laparoscopic procedures, a mesenteric defect was closed in 86%, omental flaps were fashioned in 77%, and 3 patients were diverted. Median operative time was 175 minutes. Median postoperative stay was 4 days. At 30 days, there were 2 readmissions for reintervention: 1 seton placement and 1 percutaneous drainage of a sterile collection. There were no cases of intra-abdominal sepsis or anastomotic leak., Conclusions: Mesenteric excision and exclusion represents an innovative, progressive, and promising approach that appears to be highly feasible and safe. Further study is warranted to determine if mesenteric excision and exclusion is associated with reduced postoperative recurrence of ileocolic Crohn's disease., (Copyright © The ASCRS 2021.)

Background: There are limited data on the postoperative outcomes in Crohn's disease patients exposed to preoperative ustekinumab or vedolizumab. We hypothesised that preoperative biologic use in Crohn's disease is not associated with postoperative complications after ileocolic resection., Methods: Crohn's disease patients who underwent ileocolic resection over 2009-2019 were identified at a large regional health system. Preoperative biologic use within 12 weeks of surgery was categorised as no biologic, anti-tumour necrosis factor, vedolizumab, or ustekinumab. The primary endpoint was 90-day intra-abdominal septic complication. Risk factors included preoperative medical therapies, demographics, disease characteristics, laboratory values, and surgical approach. Regression models assessed the association of biologic use with intra-abdominal septic complication., Results: A total of 815 Crohn's disease patients who underwent an ileocolic resection were included [62% no biologic, 31.4% anti-tumour necrosis factor, 3.9% vedolizumab, 2.6% ustekinumab]. Primary anastomosis was performed in 85.9% of patients [side-to-side 48.8%, end-to-side 26%, end-to-end 25%] in primarily a stapled [77.2%] manner. Minimally invasive approach was used in 41.4%. The 90-day postoperative intra-abdominal sepsis rate of 810 patients was 12%, abscess rate was 9.6%, and anastomotic leak rate was 3.2%. Multivariable regression modelling controlling for confounding variables demonstrated that preoperative biologic use with anti-tumour necrosis factor [p = 0.21], vedolizumab [p = 0.17], or ustekinumab [p = 0.52] was not significantly associated with intra-abdominal septic complication. Preoperative albumin < 3.5 g/dl was independently associated with intra-abdominal septic complication (odds ratio [OR] 1.76 [1.03, 3.01])., Conclusions: In Crohn's disease patients undergoing ileocolic resection, preoperative biologics are not associated with 90-day postoperative intra-abdominal septic complication. Preoperative biologic exposure should not delay necessary surgery., (© The Author(s) 2021. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Hypertrophy of visceral adipose tissue (VAT) is a hallmark of Crohn disease (CD). The VAT produces a wide range of adipokines, biologically active factors that contribute to metabolic disorders in addition to CD pathogenesis. The study aim was to concomitantly evaluate serum adipokine profiles and VAT volumes as predictors of disease outcomes and treatment course in newly diagnosed pediatric patients with CD., Methods: Pediatric patients ages 6 to 20 years were enrolled, and their clinical data and anthropometric measurements were obtained. Adipokine levels were measured at 0, 6, and 12 months after CD diagnosis and baseline in control patients (CP). The VAT volumes were measured by magnetic resonance imaging or computed tomography imaging within 3 months of diagnosis., Results: One hundred four patients undergoing colonoscopy were prospectively enrolled: 36 diagnosed with CD and 68 CP. The serum adipokine resistin and plasminogen activator inhibitor (PAI)-1 levels were significantly higher in patients with CD at diagnosis than in CP. The VAT volume was similar between CD and CP. Baseline resistin levels at the time of diagnosis in patients with CD who were escalated to biologics was significantly higher than in those not treated using biologic therapy by 12 months (29.8 ng/mL vs 13.8 ng/mL; P = 0.004). A resistin level of ≥29.8 ng/mL at the time of diagnosis predicted escalation to biologic therapy in the first year after diagnosis with a specificity of 95% (sensitivity = 53%; area under the curve = 0.82; P = 0.015 for model with log-scale). There was a significantly greater reduction in resistin (P = 0.002) and PAI-1 (P = 0.010) at the 12-month follow-up in patients on biologics compared with patients who were not treated using biologics., Conclusions: Serum resistin levels at diagnosis of pediatric CD predict the escalation to biologic therapy at 12 months, independent of VAT volumes. Resistin and PAI-1 levels significantly improved in patients with CD after treatment using biologics compared with those not on biologics. These results suggest the utility of resistin as a predictive biomarker in pediatric CD., (© 2020 Crohn’s & Colitis Foundation. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background and Aims: Crohn's disease (CD) is a chronic illness that affects both the pediatric and adult populations with an increasing worldwide prevalence. We aim to identify a large, single-center cohort of patients with CD using natural language processing (NLP) in combination with codified data and extract surgical rates and medication usage from the electronic medical record (EMR)., Methods: Patients with CD were identified from the entire Cleveland Clinic EMR using ICD codes and CD-specific terms identified by NLP to fit a logistic regression model. Cohorts were developed for pediatric-onset (younger than 18 years) and adult-onset (18 years and older) CD. Surgeries were identified using current procedural terminology (CPT) codes and NLP. Crohn's disease-related medications were extracted using physician orders in the EMR., Results: Patients with pediatric-onset (n = 2060) and adult-onset (n = 4973) CD were identified from 2000 to 2017 with a positive predictive value of 98.5%. Rate of CD-related abdominal surgery over time was significantly higher in adult-onset compared with pediatric-onset CD (10-year surgery rate 49.9% vs 37.7%, respectively; P < 0.001). Treatment with biologics was significantly higher in pediatric vs adult-onset CD cohorts (63.6% vs 49.2%; P < 0.001). The overall rate of CD-related abdominal surgery was significantly higher in those who received <6 months of a biologic compared with ≥6 months of a biologic for both cohorts (pediatric 64.1% vs 39.1%, P ≤ 0.001; adult 69.3% vs 56.5%, P ≤ 0.001). Additionally, 60.9% in pediatric-onset CD and 43.5% in adult-onset CD treated with ≥6 months of biologic therapy have not required abdominal surgery. On multivariable analysis, perianal surgery was a significant risk factor for abdominal surgery in both cohorts., Conclusion: We used a combination of codified and NLP data to establish the largest, North American, single-center EMR cohort of pediatric- and adult-onset CD patients and determined that biologics are associated with lower rates of surgery over time, potentially altering the natural history of the disease., (© 2020 Crohn’s & Colitis Foundation. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Gastrointestinal (GI) symptoms are seen in patients with COVID-19. The prevalence could be as high as 50%, but most studies show ranges from 16% to 33%. Presenting with GI symptoms increases the risk of testing positive for SARs-CoV-2. Approximately 50% of patients with COVID-19 have detectable virus in their stool. Having GI symptoms has been associated with more severe disease. Management of GI symptoms is mainly supportive. Healthcare providers should be aware of the GI manifestations of COVID-19 and perform SARS-CoV-2 testing for patients presenting with digestive changes, especially in those with respiratory symptoms., (Copyright © 2021 The Cleveland Clinic Foundation. All Rights Reserved.)

Background: Medical therapy and/or endoscopic balloon dilation with intralesional therapies are options for the treatment of small bowel fibrostenotic Crohn's disease (CD)., Aim: To perform a systematic review summarising evidence for efficacy of systemic and endoscopic intralesional medical therapy in established small bowel strictures in adult CD patients., Methods: A systematic search of MEDLINE, EMBASE, CENTRAL and Scopus was conducted. Primary outcomes were rates of surgical resection and repeat endoscopic dilation. Pooled event rates from random effects models across studies with 95% confidence intervals were reported., Results: Ten studies describing systemic medical therapy and eight studies of intralesional injection were included. One randomised controlled trial each for systemic therapy and intrastricture injection were identified. Only observational studies were found for systemic biologic therapies, which exclusively included tumour necrosis factor (TNF) antagonists, while intralesional therapies all involved corticosteroids except for one study that evaluated infliximab. Pooled event rates for surgical resection after systemic and intralesional therapy were 28.3% (95% CI: 18.2%-41.3%) and 18.5% (95% CI: 8.3%-36.2%), respectively over a median follow-up of 23 months (range 5.5-105.8), and 21.8 months (range 5-47). Risk of repeat endoscopic balloon dilation in those with intralesional therapy was 58.3% (95% CI: 36.6%-77.3%) over a median follow-up of 21.8 months (range 5-47)., Conclusions: There are no favoured therapies for patients with stricturing small bowel CD. Data are lacking for ustekinumab and vedolizumab. No endoscopic intralesional medications provided a clear benefit for prevention of repeat EBD or surgery., (© 2020 John Wiley & Sons Ltd.)

Despite advancements in medical therapy, many patients with Crohn's disease continue to require surgery for intestinal resection and/or management of perianal disease at some point in their disease course. Unfortunately, in this complex group of patients, postoperative disease recurrence rates are high. Medical prophylaxis can be used to prevent Crohn's disease recurrence or manage residual disease after surgery, but the ideal timing to start medications after surgery varies based on patient risk factors and patient preference for medication use. Currently, the largest medical treatment effects are seen with thiopurines and antitumor necrosis factor antibodies, but there are continually expanding options as new medical therapies are developed. A proposed algorithm stratified based on patient risk factors is provided.

Scientific research into the effects and mechanisms of acupuncture for gastrointestinal diseases including inflammatory bowel disease has been rapidly growing in the past several decades. In this review, we discuss the history, theory, and methodology of acupuncture and review potentially beneficial mechanisms of action of acupuncture for managing inflammatory bowel disease. Acupuncture has been shown to decrease disease activity and inflammation via increase of vagal activity in inflammatory bowel disease. Acupuncture has demonstrated beneficial roles in the regulation of gut dysbiosis, intestinal barrier function, visceral hypersensitivity, gut motor dysfunction, depression/anxiety, and pain, all of which are factors that can significantly impact quality of life in patients with inflammatory bowel disease. A number of clinical trials have been performed to investigate the therapeutic effects of acupuncture in ulcerative colitis and Crohn's disease. Although the data from these trials are promising, more studies are needed given the heterogeneous and multifactorial aspects of inflammatory bowel disease. There is also an important need to standardize acupuncture methodology, study designs, and outcome measurements., (© 2018 Crohn’s & Colitis Foundation. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Inflammatory bowel diseases (IBDs) are considered immune-mediated disorders with dysregulated innate and adaptive immunities. Secondary immunogloblin deficiency can occur in IBD and its impact on the disease course of IBD is not clear., Aims: We sought to determine associations between low IgG/G1 levels and poor clinical outcomes in IBD patients., Methods: This historic cohort study was performed on IBD patients with obtained IgG/IgG1 levels. The primary outcome was defined as any IBD-related bowel resection surgery and/or hospitalization. Subgroup analyses assessed particular surgical outcomes in Crohn's disease (CD), ulcerative colitis (UC) or indeterminate colitis (IC), and ileal pouch-anal anastomosis (IPAA). The secondary outcomes included IBD drug escalations and C. difficile or cytomegalovirus infections., Results: A total of 136 IBD patients had IgG/G1 levels checked and adequate follow-up, 58 (42.6 %) with normal IgG/G1 levels and 78 (57.4 %) having low levels. A total of 49 patients (62.8 %) with low immunoglobulin levels had IBD-related surgeries or hospitalizations, compared to 33 patients (56.9 %) with normal levels [odds ratio (OR) 1.28, 95 % confidence interval (CI) 0.64-2.56; p = 0.49]. Low IgG/G1 levels were associated with IBD-related surgery in CD in univariate analysis [hazard ratio (HR) 4.42, 95 % CI 1.02-19.23; p = 0.048] and in Kaplan-Meier survival curve analysis (p = 0.03), with a trend toward significance on multivariate analysis (HR 3.07, 95 % CI 0.67-14.31; p = 0.15). IBD patients with low IgG/G1 levels required more small bowel resections (12.8 vs. 1.7 %, p = 0.024) and 5-aminosalicylate initiations (28.2 vs. 13.8 %, p = 0.045)., Conclusions: Our study demonstrated a possible association between low IgG/G1 levels and poor outcomes in CD including surgery. Future implications include using immunoglobulin levels in IBD patients as a prognostic indicator or boosting humoral immunity as a treatment in this subset.

Background & Aims: Genome-wide association studies have identified 200 inflammatory bowel disease (IBD) loci, but the genetic architecture of Crohn's disease (CD) and ulcerative colitis remain incompletely defined. Here, we aimed to identify novel associations between IBD and functional genetic variants using the Illumina ExomeChip (San Diego, CA)., Methods: Genotyping was performed in 10,523 IBD cases and 5726 non-IBD controls. There were 91,713 functional single-nucleotide polymorphism loci in coding regions analyzed. A novel identified association was replicated further in 2 independent cohorts. We further examined the association of the identified single-nucleotide polymorphism with microbiota from 338 mucosal lavage samples in the Mucosal Luminal Interface cohort measured using 16S sequencing., Results: We identified an association between CD and a missense variant encoding alanine or threonine at position 391 in the zinc transporter solute carrier family 39, member 8 protein (SLC39A8 alanine 391 threonine, rs13107325) and replicated the association with CD in 2 replication cohorts (combined meta-analysis P = 5.55 × 10(-13)). This variant has been associated previously with distinct phenotypes including obesity, lipid levels, blood pressure, and schizophrenia. We subsequently determined that the CD risk allele was associated with altered colonic mucosal microbiome composition in both healthy controls (P = .009) and CD cases (P = .0009). Moreover, microbes depleted in healthy carriers strongly overlap with those reduced in CD patients (P = 9.24 × 10(-16)) and overweight individuals (P = 6.73 × 10(-16))., Conclusions: Our results suggest that an SLC39A8-dependent shift in the gut microbiome could explain its pleiotropic effects on multiple complex diseases including CD., (Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background: The significance of serrated lesions in inflammatory bowel disease (IBD) remains unclear. We aim to characterize synchronous and metachronous lesions in IBD patients with an index serrated polyp and compare them to sporadic subjects with SSP., Methods: Serrated lesions in patients with IBD were identified from a pathology database and, after review, were reclassified as hyperplastic (HP), sessile serrated (SSPs), or serrated polyps unclassifiable (SPU)., Results: One hundred thirty-four IBD patients were found to have 147 serrated polyps at index colonoscopy. SSPs were more likely to be located in the right colon: SSP (76.0%), SPU (41.7%) and HP (27.8%); P = 0.002. Synchronous multifocal visible dysplasia occurred more frequently in the SSP or SPU groups (44.5% and 66%) compared to the HP group (12%); P = 0.031. Among 13 IBD patients with index SSP followed over a median of 6 years, 61.5% developed metachronous visible dysplasia or additional SSPs. Larger index SSP size was associated with higher risk of developing subsequent visible dysplasia with a 10% increase for every 1 mm increase in size (HR = 1.1; P = 0.028), but was not associated with developing subsequent SSP (P = 0.50). The risk of subsequent SSP or visible dysplasia was no different between the IBD and non-IBD groups, but there was a trend suggesting SSP may be a marker of increased early risk of metachronous visible dysplasia in IBD patients., Conclusions: IBD patients with an index SSP and SPU have a heightened risk of synchronous multifocal visible dysplasia. Additionally, IBD patients with SSP may be at risk of early metachronous visible dysplasia.

Protein-truncating variants protective against human disease provide in vivo validation of therapeutic targets. Here we used targeted sequencing to conduct a search for protein-truncating variants conferring protection against inflammatory bowel disease exploiting knowledge of common variants associated with the same disease. Through replication genotyping and imputation we found that a predicted protein-truncating variant (rs36095412, p.R179X, genotyped in 11,148 ulcerative colitis patients and 295,446 controls, MAF=up to 0.78%) in RNF186, a single-exon ring finger E3 ligase with strong colonic expression, protects against ulcerative colitis (overall P=6.89 × 10(-7), odds ratio=0.30). We further demonstrate that the truncated protein exhibits reduced expression and altered subcellular localization, suggesting the protective mechanism may reside in the loss of an interaction or function via mislocalization and/or loss of an essential transmembrane domain.

Purpose of Review: Inflammatory bowel disease (IBD) has long been known to have genetic risk factors because of increased prevalence in the relatives of affected individuals. However, genome-wide association studies have only explained limited heritability in IBD. The observed globally rising incidence of IBD has implicated the role of environmental factors. The hidden unexplained heritability remains to be explored., Recent Findings: Recent aggregate evidence has highlighted the extent and nature of host genome-microbiome associations, a key next step in understanding the mechanisms of pathogenesis in IBD. An individual's gut microbiota is shaped not only by genetic but also by environmental factors like diet. Minimizing exposure of the intestinal lumen to selected food items has shown to prolong the remission state of IBD. Among a genetically susceptible host, the shift of gut microbiota (or 'dysbiosis') can lead to increasing the susceptibility to IBD. With the advances in high-throughput large-scale 'omics' technologies in combination with creative data mining and system biology-based network analyses, the complexity of biological functional networks behind the cause of IBD has become more approachable. Therefore, the hidden heritability in IBD has become more explainable, and can be attributable to the changing environmental factors, epigenetic modifications, and gene-host microbial ('in-vironmental') or gene-extrinsic environmental interactions., Summary: This review discusses the perspectives of relevance to clinical translation with emphasis on gene-environment interactions. No doubt, the use of system-based approaches will lead to the development of alternative, and hopefully better, diagnostic, prognostic, and monitoring tools in the management of IBD.

Background: Increased abdominal visceral adipose tissue (VAT) is associated with systemic inflammation. The influence of VAT on pediatric inflammatory bowel disease (IBD) has not been studied. The objective of this study was to investigate the differences in VAT between pediatric patients with IBD and age-matched controls and identify associations between VAT and Crohn's disease (CD) outcomes., Methods: Single-center retrospective cohort study of 114 pediatric patients with IBD (101 CD and 13 ulcerative colitis) who had abdominal computed tomography at diagnosis. VAT volumes were measured from computed tomography images. A control group of 78 age-matched patients without IBD who had abdominal computed tomography was selected for comparison., Results: Median VAT was 634 cm (interquartile range, 411-1041) in the IBD group and 659 cm (interquartile range, 394-1015) in the controls. IBD group had 33% higher VAT than controls (95% confidence interval [CI], 11-58) P = 0.002 after adjusting for body mass index and age. In patients with CD, higher VAT was associated with fistulizing or fibrostenotic disease (odds ratio [OR], 1.7; 95% CI, 1.1-2.9; P = 0.03), CD hospitalizations (OR, 1.9; 95% CI, 1.2-3.4; P = 0.01), moderate or severe disease activity scores (OR, 1.8; 95% CI, 1.1-3.1; P = 0.02), and shorter intervals from diagnosis to surgery (hazard ratio, 1.4; 95% CI, 1.0-2.0; P = 0.05) after adjusting for body mass index and age., Conclusions: At diagnosis, pediatric patients with IBD have higher adjusted VAT volumes than age- and body mass index-matched controls. Higher VAT volumes in pediatric patients with CD predicted more hospitalizations, increased likelihood of complicated disease, shorter interval from diagnosis to surgery, and higher disease activity scores at diagnosis.

Background: Inflammation is increasingly being recognized as an important factor in the pathogenesis of atherosclerosis and outcome of percutaneous coronary intervention (PCI). The purpose of this study was to compare conventional risk factors and PCI outcomes in patients with inflammatory bowel disease (IBD) and non-IBD controls with angiographically proven coronary artery disease (CAD)., Methods: We performed a historical cohort study of patients with IBD who were diagnosed with CAD by cardiac catheterization between January 2004 and June 2010. Four non-IBD controls with CAD were matched to each IBD case. Framingham risk score and corresponding 10-year coronary heart disease risk were calculated for all the patients. Outcomes were obtained using a prospectively maintained Institutional Interventional Catheterization Database., Results: One hundred thirty-one patients with IBD (54 Crohn's disease, 77 ulcerative colitis) with CAD and 524 matched non-IBD controls with CAD were included. Patients with IBD were younger (65.3 ± 10.0 versus 67.8 ± 11.0 yr, P = 0.016), had lower prevalence of active tobacco use (10.7% versus 18.7%, P = 0.03), and had lower body mass index (28.0 ± 5.1 versus 29.4 ± 6.4, P = 0.026) compared with controls. Patients with IBD had lower rates of severe left anterior descending artery disease (56% versus 73%, P < 0.0002) and multivessel CAD (71% versus 79%, P = 0.05). There was no difference in post-PCI major adverse cardiovascular outcomes (defined as all-cause death, myocardial infarction, cerebrovascular events, and target lesion revascularization)., Conclusions: Patients with IBD are diagnosed with CAD at a younger age as compared with non-IBD patients, are less likely to be active smokers and have lower body mass index. Post-PCI outcomes in patients with IBD with CAD are similar to non-IBD controls with CAD.

Background: Markers that predict the occurrence of a complicated disease behavior in patients with Crohn's disease (CD) can permit a more aggressive therapeutic regimen for patients at risk. The aim of this cohort study was to test the blood levels of hemoglobin (Hgb) and hematocrit (Hct) for the prediction of complicated CD behavior and CD related surgery in an adult patient population., Methods: Blood samples of 62 CD patients of the German Inflammatory Bowel Disease-network "Kompetenznetz CED" were tested for the levels of Hgb and Hct prior to the occurrence of complicated disease behavior or CD related surgery. The relation of these markers and clinical events was studied using Kaplan-Meier survival analysis and adjusted COX-proportional hazard regression models., Results: The median follow-up time was 55.8 months. Of the 62 CD patients without any previous complication or surgery 34% developed a complication and/or underwent CD related surgery. Low Hgb or Hct levels were independent predictors of a shorter time to occurrence of the first complication or CD related surgery. This was true for early as well as late occurring complications. Stable low Hgb or Hct during serial follow-up measurements had a higher frequency of complications compared to patients with a stable normal Hgb or Hct, respectively., Conclusions: Determination of Hgb or Hct in complication and surgery naïve CD patients might serve as an additional tool for the prediction of complicated disease behavior.

Genome-wide association studies (GWAS) have identified at least 133 ulcerative colitis (UC) associated loci. The role of genetic factors in clinical practice is not clearly defined. The relevance of genetic variants to disease pathogenesis is still uncertain because of not characterized gene-gene and gene-environment interactions. We examined the predictive value of combining the 133 UC risk loci with genetic interactions in an ongoing inflammatory bowel disease (IBD) GWAS. The Wellcome Trust Case-Control Consortium (WTCCC) IBD GWAS was used as a replication cohort. We applied logic regression (LR), a novel adaptive regression methodology, to search for high-order interactions. Exploratory genotype correlations with UC sub-phenotypes [extent of disease, need of surgery, age of onset, extra-intestinal manifestations and primary sclerosing cholangitis (PSC)] were conducted. The combination of 133 UC loci yielded good UC risk predictability [area under the curve (AUC) of 0.86]. A higher cumulative allele score predicted higher UC risk. Through LR, several lines of evidence for genetic interactions were identified and successfully replicated in the WTCCC cohort. The genetic interactions combined with the gene-smoking interaction significantly improved predictability in the model (AUC, from 0.86 to 0.89, P = 3.26E-05). Explained UC variance increased from 37 to 42 % after adding the interaction terms. A within case analysis found suggested genetic association with PSC. Our study demonstrates that the LR methodology allows the identification and replication of high-order genetic interactions in UC GWAS datasets. UC risk can be predicted by a 133 loci and improved by adding gene-gene and gene-environment interactions.

Background: Genome-wide association studies have identified at least 71 Crohn's disease (CD) genetic risk loci, but the role of gene-gene interactions is unclear. The value of genetic variants in clinical practice is not defined because of limited explained heritability., Methods: We examined model predictability of combining the 71 CD risk alleles and genetic interactions in an ongoing inflammatory bowel disease genome-wide association study. The Wellcome Trust Case Control Consortium inflammatory bowel disease genome-wide association study was used as a replicate cohort. We used logic regression, an adaptive regression methodology, to search for high-order binary predictors (e.g., single-nucleotide polymorphism [SNP] interactions)., Results: The combined 71 CD SNPs had good CD risk predictability (area under the curve of 0.75 and 0.73 in the 2 cohorts). Higher cumulative allele score predicted higher CD risk, but a relatively small difference in cumulative allele scores was observed between CD and controls (49 versus 47, P < 0.001). Through LR, we identified high-order genetic interactions and significantly improved the model predictability (area under the curve, from 0.75 to 0.77, P < 0.0001). A genetic interaction model, including NOD2, ATG16L1, IL10/IL19, C13orf31, and chr21q loci, was discovered and successfully replicated in the independent Wellcome Trust Case Control Consortium cohort. The explained heritability of the 71 CD SNPs alone was 24% and increased to 27% after adding the genetic interactions., Conclusions: A novel approach allowed the identification and replication of genetic interactions among NOD2, ATG16L1, IL10/IL19, C13orf31, and chr21q loci. CD risk can be predicted by a model of 71 CD loci and improved by adding genetic interactions.