Pediatric Crohn's Disease Research Articles

Formula modifications to the Crohn's disease exclusion diet donot impacttherapy success in paediatric Crohn's disease.

The Crohn's disease exclusion diet (CDED) + partial enteral nutrition (PEN) is an emerging diet used to induce clinical remission in children with active Crohn's disease (CD). This study aims to determine the effectiveness of using the CDED+PEN to induce clinical remission in an Australian group of children with active CD using different PEN formulas and incorporating patient dietary requirements. We retrospectively collected data from children (both newly diagnosed and with existing CD while on therapy) with active CD (Paediatric Crohn's Disease Activity Index [PCDAI] ≥10)and biochemical evidence of active disease (elevated C-reactive protein [CRP], erythrocyte sedimentation rate [ESR] or faecal calprotectin [FC]) who completed at least phase 1 (6 weeks) of the CDED+PEN to induce clinical remission. Data werecollected at baseline, Week 6 and Week 12. The primary endpoint was clinical remission at Week 6 defined as PCDAI < 10. Twenty-four children were included in phase 1 analysis (mean age 13.8 ± 3.2 years). Clinical remission at Week 6 was achieved in 17/24 (70.8%) patients. Mean PCDAI, CRP, ESR and FC decreased significantly after 6 weeks (p < 0.05). Formula type (cow's milk based, rice based, soy based) did not affect treatment efficacy. A greater than 50% decrease in FC was achieved in 14/21 (66.7%) patients who completed phase 1 and 12/14 (85.7%) patients who completed phase 2 of the CDED+PEN. Formula modifications to the CDED+PEN do not impact the expected treatment efficacy in Australian children with active luminal CD.

Risk Factors for Complications and Disease Recurrence after Ileocecal Resection for Crohn's Disease in Children and Adults.

This study reports the complication and disease recurrence rates for ileocecal resection for pediatric and adult Crohn's disease (CD) and identifies perioperative risk factors for these adverse outcomes in the two groups. Patients who underwent ileocecal resection for CD in a tertiary hospital in Italy (2010-2021) were included. Risk factors for postoperative complications and clinical and surgical disease recurrences were investigated with multivariate models. A total of 96 patients were included (children, 25%). There were no intraoperative complications. Thirty-one (32.3%) patients experienced 35 (36.5%) postoperative complications, and five (5.2%) were severe (Clavien-Dindo III-IV-V), with no intergroup difference for either overall postoperative complication rate (p = 0.257) or severe postoperative complication rate (p = 0.097). Most of these (77.1%) occurred within 30 days after surgery, especially in adults (p = 0.013). The multivariate analysis did not show risk factors for postoperative complications. Clinical and surgical recurrence rates after 5 years were 46.8% and 14.6%, respectively, with no intergroup rate differences. Clinical disease recurrence was positively correlated with previous abdominal surgery (p = 0.047) and negatively correlated with preoperative Hb levels (p = 0.046). A positive correlation was found between perianal disease and both clinical (p = 0.045) and surgical disease recurrences (p = 0.045). Urgent surgery was positively associated with surgical disease recurrence (p = 0.045). Notably, no children underwent urgent surgery in this study. In conclusion, the risk of postoperative complications among CD patients receiving ileocecal resection remains high, but most of them are nonserious. Some factors, such as urgent surgery, may increase the risk of disease recurrences.

Ustekinumab in pediatric patients with Crohn's disease: safety, and efficacy results from a multicenter retrospective study in China.

Ustekinumab (UST) is approved as an effective therapy for Crohn's disease (CD) in adults. Off-label use is increasing in the pediatric population, more data on safety and efficacy in pediatric patients with CD is urgently needed. This study aimed to evaluate the clinical efficacy and safety of UST in children and adolescents with Crohn's disease. This multicenter retrospective study carried out at three tertiary care centers, and identified children who received their first dose of UST at 18 years old or younger and followed up for a minimum of 24 weeks. Data on demographics, disease behavior, location and activity, treatment history were collected. The primary outcomes were clinical remission at weeks 24-32 and weeks 48-56 of UST therapy. Secondary outcomes were clinical response at the same time points, endoscopic remission, changes in C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), albumin and fecal calprotectin, improvement in growth parameters, and rate of adverse events. Sixteen patients were included, and 11/13 (84.6%) continued to receive UST after 1 year. Our data demonstrate that the clinical remission rates were 41.7% at weeks 24∼32 with the Weighted pediatric CD activity index (wPCDAI) was lower than baseline (43.8, IQR: 31.3-51.9 vs.15, IQR: 5.6-25, p < 0.001) and 75% at weeks 48-56 with wPCDAI was lower than baseline (42.5, IQR: 23.8-50 vs. 7.5, IQR: 0-13.8, p = 0.004). Five of eleven children achieved endoscopic remission. No serious adverse events were recorded during the study period. UST is efficacious and safe in pediatric patients with CD. Pediatric patients could benefit from UST as either a primary or secondary biologic therapy for the induction, or maintenance of remission of CD.

Clinical effectiveness and safety of ustekinumab in youth with refractory inflammatory bowel disease: A retrospective cohort study.

Inflammatory bowel disease (IBD) incidence and prevalence has been increasing worldwide. Limited data exists on the effectiveness of ustekinumab (UST) in children. We aimed to describe the effectiveness and safety of UST in pediatric patients with IBD. A single-center retrospective study was conducted between January 2017 and February 2022. The study included patients ≤16 years of age who were treated with UST and followed up for ≥1 year. Clinical remission was defined as a score of the Pediatric Crohn's Disease (CD) and Pediatric Ulcerative Colitis (UC) Activity Indices ≤10 at week 52. Thirteen patients who had failed anti-tumor necrosis factor-α (anti-TNFα) therapy were included, eight (61.5%) with CD and five (38.5%) with UC. The median age was 13 years (interquartile range [IQR]: 11.5 to 14). UST treatment was initiated at a median age of 3 years (IQR: 2.3 to 7) after diagnosis. Ten patients (76.9%) achieved clinical remission. There were no statistically significant differences in characteristics between patients who achieved and did not achieve clinical remission. Biochemical remission (BioR) was achieved in six patients (46.2%). Body mass index (BMI) significantly improved, C-reactive protein (CRP) significantly decreased, and the need for corticosteroids significantly decreased in the remission group. Endoscopy conducted post-treatment in seven patients confirmed remission in six patients. Adverse events included two cases of infection and one of headache. UST was effective as a secondary biologic therapy for the induction and maintenance of remission in patients with anti-TNFα refractory IBD. At one year, 84% of patients remained on UST with no severe adverse reactions reported.

Pre-Diagnosis Diet Predicts Response to Exclusive Enteral Nutrition and Correlates with Microbiome in Pediatric Crohn Disease.

Exclusive enteral nutrition (EEN) is effective in inducing remission in pediatric Crohn disease (CD). EEN alters the intestinal microbiome, but precise mechanisms are unknown. We hypothesized that pre-diagnosis diet establishes a baseline gut microbiome, which then mediates response to EEN. We analyzed prospectively recorded food frequency questionnaires (FFQs) for pre-diagnosis dietary patterns. Fecal microbiota were sequenced (16SrRNA) at baseline and through an 18-month follow-up period. Dietary patterns, Mediterranean diet adherence, and stool microbiota were associated with EEN treatment outcomes, disease flare, need for anti-tumor necrosis factor (TNF)-α therapy, and long-term clinical outcomes. Ninety-eight patients were included. Baseline disease severity and microbiota were associated with diet. Four dietary patterns were identified by FFQs; a "mature diet" high in fruits, vegetables, and fish was linked to increased baseline microbial diversity, which was associated with fewer disease flares (p < 0.05) and a trend towards a delayed need for anti-TNF therapy (p = 0.086). Baseline stool microbial taxa were increased (Blautia and Faecalibacterium) or decreased (Ruminococcus gnavus group) with the mature diet compared to other diets. Surprisingly, a "pre-packaged" dietary pattern (rich in processed foods) was associated with delayed flares in males (p < 0.05). Long-term pre-diagnosis diet was associated with outcomes of EEN therapy in pediatric CD; diet-microbiota and microbiota-outcome associations may mediate this relationship.

Reverse-engineered exclusive enteral nutrition in pediatric Crohn's disease: A pilot trial.

In pediatric Crohn's disease (CD), commercial formulas used as exclusive enteral nutrition (EEN) are effective at inducing remission. This study aims to assess the impact of a whole-food blended smoothie as EEN on CD activity and the intestinal microbiome. A 4-week prospective trial assessed the impact of EEN with a whole-food smoothie on newly diagnosed mild-to-moderate active pediatric CD. The smoothie with a multivitamin were developed to meet age-appropriate nutritional requirements. Assessment over 4 weeks included Pediatric Crohn's Disease Activity Index (PCDAI), serum laboratories, fecal calprotectin (FCP), and stool collection for metagenomic shotgun sequencing and microbiota composition analysis. Clinical remission was defined as PCDAI ≤ 10 at week 4. Ten participants were enrolled with median age 14.5 years, and 8 completed the trial. Baseline mean PCDAI was 26.3 ± 9.1 and mean FCP 1149 ± 718 µg/g. At week 4, 80% of participants achieved clinical remission. FCP decreased by over half in 60% of participants, with FCP below 250 µg/g in 60% and below 100 µg/g in 40%. Microbiome analysis showed a significant increase in species richness over 4 weeks (p = 0.01). Compared to baseline, the relative abundance at week 2 and at week 4 was significantly increased for Bifidobacterium and Streptococcus and decreased for Blautia (p < 0.05 for all). A whole-food blended smoothie was effective for inducing clinical remission and decreasing FCP in pediatric CD similar to commercial EEN formulas. Further research may give insight into data-driven whole-food dietary approaches for CD management. gov NCT03508193.

Surgical management of complicated Crohn's disease

Surgical management of pediatric Crohn's disease is fundamentally palliative, aiming to treat the sequalae of complicated disease while preserving intestinal length. Multidisciplinary discussion of risk factors and quality of life should take place prior to operative intervention. Though the surgical management of pediatric Crohn's disease is largely based on the adult literature, there are considerations specific to the pediatric population – notably disease and treatment effects on growth and development. Intrabdominal abscess is approached with percutaneous drainage when feasible, reserving surgical intervention for the patient who is unstable or failing medical therapy. Pediatric patients with fibrostenotic disease should be considered for strictureplasty when possible, for maximum preservation of bowel length. Patients with medically refractory Crohn's proctocolitis should be treated initially with fecal diversion without proctocolectomy.

Operating Properties of Disease Activity Indices in Pediatric Inflammatory Bowel Disease: A Systematic Review.

Accurate, reliable, and responsive disease activity indices are important to streamline drug approval and treatment modalities for pediatric inflammatory bowel disease (pIBD). We aimed to identify all scoring indices used in pIBD randomized controlled trials (RCTs) and to evaluate their operating properties. MEDLINE, EMBASE, and CENTRAL were searched on December 6, 2022, to identify studies evaluating clinical, endoscopic, imaging, or patient-reported outcome measures (PROMs) in pIBD including Crohn's disease (CD) and ulcerative colitis (UC). Validity, reliability, responsiveness, and feasibility were summarized. Seventy RCTs evaluating pIBD indices were identified. Forty-one studies reported on the operating properties of 14 eligible indices (n = 9 CD, n = 5 UC). The Pediatric Crohn's Disease Activity Index (PCDAI) varied widely in terms of validity and reliability and was less feasible overall. In contrast, the Mucosal Inflammation Noninvasive Index, which includes fecal calprotectin, had better operating properties than the PCDAI. The Simplified Endoscopic Mucosal Assessment of Crohn's Disease appears more feasible and had similar operating properties than the longer Simple Endoscopic Score for Crohn's Disease. The Pediatric Ulcerative Colitis Activity Index was feasible, valid, and reliable, but responsiveness needs to be evaluated further. The Endoscopic Mayo score and the Ulcerative Colitis Endoscopic Index of Severity were reliable, but validity and responsiveness need to be evaluated further. Imaging and PROMs/quality of life indices need further evaluation. The operating properties of pIBD clinical trial end points varied widely. These results highlight the need for further validation and development of novel indices.

Recurrent Crohn's disease

Although surgical management of the ileocolic segment in pediatric Crohn's disease is not curative, the main goal of therapy is to allow for growth, adequate nutrition, and age-appropriate development. Recurrent disease at the site of anastomosis presents as a major morbidity. Several factors have been implicated in the development of surgical recurrence though data in the literature is scarce. This review explores the epidemiology of recurrent ileocolic disease following primary surgery, indications for surgical intervention, and techniques reported in the literature. Pediatric data is scarce, and therefore, much of it is extrapolated from adult literature.

Surgical management of pediatric Crohn's disease

Management of pediatric-onset Crohn's disease uniquely necessitates consideration of growth, pubertal development, psychosocial function and an increased risk for multiple future surgical interventions. Both medical and surgical management are rapidly advancing; therefore, it is increasingly important to define the role of surgery and the breadth of surgical options available for this complex patient population. Particularly, the introduction of biologics has altered the disease course; however, the ultimate need for surgical intervention has remained unchanged. This review defines and evaluates the surgical techniques available for management of the most common phenotypes of pediatric-onset Crohn's disease as well as identifies critical perioperative considerations for optimizing post-surgical outcomes.

Correlation of Socioeconomic and Environmental Factors With Incidence of Crohn Disease in Children and Adolescents: Systematic Review and Meta-Regression.

The worldwide incidence of Crohn disease (CD) in childhood and adolescence has an increasing trend, with significant differences between different geographic regions and individual countries. This includes an increase in the incidence of CD in countries and geographic regions where CD was not previously prevalent. In response to the increasing incidence, the pediatric care landscape is facing growing challenges. This systematic review and meta-analysis were undertaken to comprehensively delineate the incidence rates of CD in pediatric populations across different countries and to explore potential influencing factors. We performed a systematic review of PubMed and Embase (via Ovid) for studies from January 1, 1970, to December 31, 2019. In addition, a manual search was performed in relevant and previously published reviews. The results were evaluated quantitatively. For this purpose, random effects meta-analyses and meta-regressions were performed to investigate the overall incidence rate and possible factors influencing the incidence. A qualitative synthesis of 74 studies was performed, with 72 studies included in the meta-analyses and 52 in the meta-regressions. The results of our meta-analysis showed significant heterogeneity between the individual studies, which cannot be explained by a sample effect alone. Our findings showed geographical differences in incidence rates, which increased with increasing distance from the equator, although no global temporal trend was apparent. The meta-regression analysis also identified geographic location, UV index, and Human Development Index as significant moderators associated with CD incidence. Our results suggest that pediatric CD incidence has increased in many countries since 1970 but varies widely with geographic location, which may pose challenges to the respective health care systems. We identified geographic, environmental, and socioeconomic factors that contribute to the observed heterogeneity in incidence rates. These results can serve as a basis for future research. To this end, implementations of internationally standardized and interoperable registries combined with the dissemination of health data through federated networks based on a common data model, such as the Observational Medical Outcomes Partnership, would be beneficial. This would deepen the understanding of CD and promote evidence-based approaches to preventive and interventional strategies as well as inform public health policies aimed at addressing the increasing burden of CD in children and adolescents. PROSPERO International prospective register of systematic reviews CRD42020168644; https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=168644. RR2-10.1136/bmjopen-2020-037669.

High Body Mass Index and Response to Anti-Tumor Necrosis Factor Therapy in Pediatric Crohn's Disease.

Obesity is common among patients with pediatric Crohn's disease (PCD). Some adult studies suggest obese patients respond less well to anti-tumor necrosis factor (TNF) treatment. This study sought compares anti-TNF response and anti-TNF levels between pediatric patients with normal and high body mass index (BMI). The COMBINE trial compared anti-TNF monotherapy with combination therapy with methotrexate in patients with PCD. In this secondary analysis, a comparison of time-to-treatment failure among patients with normal BMI vs BMI Z -score >1, adjusting for prescribed anti-TNF (infliximab [IFX] or adalimumab [ADA]), trial treatment assignment (combination vs monotherapy), and relevant covariates. Median anti-TNF levels across BMI category was also examined. Of 224 participants (162 IFX initiators and 62 ADA initiators), 111 (81%) had a normal BMI and 43 (19%) had a high BMI. High BMI was associated with treatment failure among ADA initiators (7/10 [70%] vs 12/52 [23%], hazard ratio 0.29, P = 0.007) but not IFX initiators. In addition, ADA-treated patients with a high BMI had lower ADA levels compared with those with normal BMI (median 5.8 vs 12.8 μg/mL, P = 0.02). IFX trough levels did not differ between BMI groups. Overweight and obese patients with PCD are more likely to experience ADA treatment failure than those with normal BMI. Higher BMI was associated with lower drug trough levels. Standard ADA dosing may be insufficient for overweight children with PCD. Among IFX initiators, there was no observed difference in clinical outcomes or drug levels, perhaps due to weight-based dosing and/or greater use of proactive drug monitoring.

Kono-S anastomosis in Crohn's disease: initial experience in pediatric patients.

Children diagnosed with Crohn's disease (CD) often undergo ileocecal resection (ICR) during childhood. Anastomotic recurrence is a frequent finding following this procedure. Data addressing the effect of the anastomosis type on disease recurrence are scarce in the pediatric population. The Kono-S anastomosis has shown promise in reducing endoscopic, clinical, and surgical recurrence rates in adults. We aimed to report our experience with Kono-S anastomosis in children, focusing on its feasibility and postoperative complications. We retrospectively analyzed pediatric CD patients who underwent ICR with Kono-S anastomosis between August 2022 and May 2023. Data on demographics, clinical characteristics, surgery, hospitalization, and follow-up including colonoscopy were collected. Complications were classified using the Clavien-Dindo classification. Twelve patients (7 females, 58.3%) were included. Six (50%) of the patients had the B3 luminal form of the disease (according to Paris classification). Median surgery duration was 174 (interquartile range [IQR] 161-216) minutes. Anastomosis creation took a median of 62 (IQR, 54.5-71) minutes. Median hospitalization length was 6 (IQR 4-7) days. No short- or mid-term complications were observed. Median follow-up duration was 9.5 (IQR 6.8-12) months. According to our results, Kono-S anastomosis is safe and feasible in pediatric CD patients, with no observed postoperative complications. These findings support the potential benefit of using Kono-S anastomosis as a treatment approach in children with CD.

Aberrant miR-29 is a predictive feature of severe phenotypes in pediatric Crohn's disease.

Crohn's disease (CD) is a chronic inflammatory gut disorder. Molecular mechanisms underlying the clinical heterogeneity of CD remain poorly understood. MicroRNAs (miRNAs) are important regulators of gut physiology, and several have been implicated in the pathogenesis of adult CD. However, there is a dearth of large-scale miRNA studies for pediatric CD. We hypothesized that specific miRNAs uniquely mark pediatric CD. We performed small RNA-Seq of patient-matched colon and ileum biopsies from treatment-naive pediatric patients with CD (n = 169) and a control cohort (n = 108). Comprehensive miRNA analysis revealed 58 miRNAs altered in pediatric CD. Notably, multinomial logistic regression analysis revealed that index levels of ileal miR-29 are strongly predictive of severe inflammation and stricturing. Transcriptomic analyses of transgenic mice overexpressing miR-29 show a significant reduction of the tight junction protein gene Pmp22 and classic Paneth cell markers. The dramatic loss of Paneth cells was confirmed by histologic assays. Moreover, we found that pediatric patients with CD with elevated miR-29 exhibit significantly lower Paneth cell counts, increased inflammation scores, and reduced levels of PMP22. These findings strongly indicate that miR-29 upregulation is a distinguishing feature of pediatric CD, highly predictive of severe phenotypes, and associated with inflammation and Paneth cell loss.

Gut metabolome and microbiota signatures predict response to treatment with exclusive enteral nutrition in a prospective study in children with active Crohn’s disease

BackgroundPredicting response to exclusive enteral nutrition (EEN) in active Crohn’s disease (CD) could lead to therapy personalization and pretreatment optimization. ObjectivesThis study aimed to explore the ability of pretreatment parameters to predict fecal calprotectin (FCal) levels at EEN completion in a prospective study in children with CD. MethodsIn children with active CD, clinical parameters, dietary intake, cytokines, inflammation-related blood proteomics, and diet-related metabolites, metabolomics and microbiota in feces, were measured before initiation of 8 wk of EEN. Prediction of FCal levels at EEN completion was performed using machine learning. Data are presented with medians (IQR). ResultsOf 37 patients recruited, 15 responded (FCal < 250 μg/g) to EEN (responders) and 22 did not (nonresponders). Clinical and immunological parameters were not associated with response to EEN. Responders had lesser (μmol/g) butyrate [responders: 13.2 (8.63–18.4) compared with nonresponders: 22.3 (12.0–32.0); P = 0.03], acetate [responders: 49.9 (46.4–68.4) compared with nonresponders: 70.4 (57.0–95.5); P = 0.027], phenylacetate [responders: 0.175 (0.013–0.611) compared with nonresponders: 0.943 (0.438–1.35); P = 0.021], and a higher microbiota richness [315 (269–347) compared with nonresponders: 243 (205–297); P = 0.015] in feces than nonresponders. Responders consumed (portions/1000 kcal/d) more confectionery products [responders: 0.55 (0.38–0.72) compared with nonresponders: 0.19 (0.01–0.38); P = 0.045]. A multicomponent model using fecal parameters, dietary data, and clinical and immunological parameters predicted response to EEN with 78% accuracy (sensitivity: 80%; specificity: 77%; positive predictive value: 71%; negative predictive value: 85%). Higher taxon abundance from Ruminococcaceae, Lachnospiraceae, and Bacteroides and phenylacetate, butyrate, and acetate were the most influential variables in predicting lack of response to EEN. ConclusionsWe identify microbial signals and diet-related metabolites in feces, which could comprise targets for pretreatment optimization and personalized nutritional therapy in pediatric CD.

Identification of platelet-related subtypes and diagnostic markers in pediatric Crohn's disease based on WGCNA and machine learning.

The incidence of pediatric Crohn's disease (PCD) is increasing worldwide every year. The challenges in early diagnosis and treatment of PCD persist due to its inherent heterogeneity. This study's objective was to discover novel diagnostic markers and molecular subtypes aimed at enhancing the prognosis for patients suffering from PCD. Candidate genes were obtained from the GSE117993 dataset and the GSE93624 dataset by weighted gene co-expression network analysis (WGCNA) and differential analysis, followed by intersection with platelet-related genes. Based on this, diagnostic markers were screened by five machine learning algorithms. We constructed predictive models and molecular subtypes based on key markers. The models were evaluated using the GSE101794 dataset as the validation set, combined with receiver operating characteristic curves, decision curve analysis, clinical impact curves, and calibration curves. In addition, we performed pathway enrichment analysis and immune infiltration analysis for different molecular subtypes to assess their differences. Through WGCNA and differential analysis, we successfully identified 44 candidate genes. Following this, employing five machine learning algorithms, we ultimately narrowed it down to five pivotal markers: GNA15, PIK3R3, PLEK, SERPINE1, and STAT1. Using these five key markers as a foundation, we developed a nomogram exhibiting exceptional performance. Furthermore, we distinguished two platelet-related subtypes of PCD through consensus clustering analysis. Subsequent analyses involving pathway enrichment and immune infiltration unveiled notable disparities in gene expression patterns, enrichment pathways, and immune infiltration landscapes between these subtypes. In this study, we have successfully identified five promising diagnostic markers and developed a robust nomogram with high predictive efficacy. Furthermore, the recognition of distinct PCD subtypes enhances our comprehension of potential pathogenic mechanisms and paves the way for future prospects in early diagnosis and personalized treatment.

A222 CLINICAL EFFECTIVENESS AND SAFETY OF USTEKINUMAB IN YOUTH WITH REFRACTORY INFLAMMATORY BOWEL DISEASE IN SAUDI ARABIA: A RETROSPECTIVE COHORT STUDY

Abstract Background Inflammatory bowel disease (IBD) incidence and prevalence have been increasing worldwide with higher disease severity observed in pediatrics. Limited data exists on the effectiveness of ustekinumab (UST) in children. Aims To describe the effectiveness and safety of UST in pediatric patients with IBD. Methods A retrospective, single-center cohort study was conducted between January 2017 and February 2022. The study included patients ≤16 years of age who were treated with off-label UST and followed up for a minimum of one year. Clinical remission was defined as a decrease in the score on the Pediatric Crohn's Disease (CD) and Pediatric Ulcerative Colitis (UC) Activity Indices to ≤10 at week 52. Results A total of 13 patients who had failed anti-TNFα therapy were included, 8 (61.5%) with CD and 5 (38.5%) with UC. The median age of the patients was 13y (IQR: 11.5 to 14). UST treatment was initiated at a median of 3y (IQR: 2.3 to 7) after diagnosis. Ten patients (76.9%) achieved clinical remission. There were no statistically significant differences in baseline characteristics between patients who achieved and did not achieve clinical remission. Biochemical remission was achieved in 6 patients (46.2%). C-reactive protein levels decreased significantly in the remission group and insignificantly in the non-remission group. No significant changes were observed in erythrocyte sedimentation rate, albumin, or hemoglobin. BMI improved (Fig 1) and the need for corticosteroids significantly decreased after UST therapy in the remission group (P = 0.014). Endoscopy conducted post-treatment in 7 patients confirmed remission in 6 patients, with one patient showing clinical remission but not endoscopic remission. Adverse events included two instances of infection and once case of headache. Conclusions UST was effective as a secondary biologic therapy for the induction and maintenance of remission in patients with anti-TNFα refractory IBD. At one year, 84% of patients remained on UST with no severe adverse reactions reported. Future prospective large-scale studies are necessary to assess the therapeutic positioning and optimal dosing regimens of UST in pediatric IBD. Figure 1. Change in BMI Z-score throughout the study (P value of interaction = 0.049). Funding Agencies None

A257 EARLY PROACTIVE THERAPEUTIC DRUG MONITORING WITH USTEKINUMAB THERAPY IN PAEDIATRIC CROHN’S DISEASE

Abstract Background Ustekinumab (UST) is an effective therapy for adults with moderate to severe Crohn’s disease (CD), but data concerning optimal dosing in children are sparse. Aims To examine real-world post-induction PK and efficacy in a prospective multicentre cohort study of paediatric CD (Canadian Children IBD Network (CIDsCaNN)). Methods Children 2-17 years-old with CD were eligible for this analysis if they received IV UST for treatment of luminal CD and had serum UST levels measured at week 8. Median with interquartile range (IQR) UST dose and serum trough levels at weeks 8 and 16 were compared between children ampersand:003C40 kg and ≥40 kg with Mann-Whitney U test. Clinical remission was defined as weighted Pediatric CD Activity Index (wPCDAI) ampersand:003C12.5. UST durability was compared between those with a week 8 serum UST level ampersand:003C5 versus ≥5 µg/mL (log-rank p-value). Results Between 21/04/2017 and 30/04/2023, 39 children were eligible (74% M; median age 13.5 (IQR 11.9-15.6) y; median weight 44.7 (IQR 30.4-55.0) kg, 12 children ampersand:003C40 kg; 84% bio-naïve). Median disease duration at UST start was 4 (IQR 1-17) months; CD location distal ileal ± limited cecal (18%), colonic (26%), ileocolonic (54%). Median follow-up duration was 10.0 (IQR 6.7-12.7) months. All children received UST IV induction (67% 260 mg, 18% 390 mg) followed by 90 mg SC every 8 weeks. Induction doses in mg per kg were higher in those ampersand:003C40 kg (median 9.11 (IQR 8.68-10.08)) compared to those ≥40 kg (5.77 (IQR 5.24-6.45) mg/kg), pampersand:003C0.001. Induction doses in mg per body surface area (BSA) in m2 were similarly higher in those ampersand:003C40 kg (median 251.66 (IQR 244.16-258.99) versus 195.15 (IQR 172.71-224.11) mg/m2, pampersand:003C0.001). Despite higher induction doses, week 8 trough levels were numerically lower in those ampersand:003C40 kg (median 4.32 (IQR 1.33-8.36) versus 6.96 (IQR 5.38-8.90) µg/mL, p=0.29). Week 16 serum UST levels were also numerically lower in ampersand:003C40 kg versus ≥40 kg (median 4.04 (IQR 1.92-6.98) versus 5.50 (IQR 3.17-8.27) µg/mL, p=0.57). Interval shortening during maintenance to every 4 weeks occurred in 7 children prior to week 16, and in 14 children prior to 6 months. By 4 months, 19 of 33 children with available data (56%) achieved clinical remission. Overall, 8/39 (21%) ceased UST. Those who discontinued UST had significantly lower week 8 levels than those who continued UST (median 3.52 (IQR 1.19-6.12) versus 7.15 (IQR 5.09-10.15) µg/mL, p=0.027). In survival analysis, week 8 trough level ampersand:003C5 µg/mL was associated with an increased risk of UST discontinuation (log-rank p=0.032) (Figure 1). Conclusions Higher UST concentration at week 8 is associated with greater drug durability. A higher BSA-based induction for children ampersand:003C40 kg is supported by higher serum drug levels and improved drug durability. Figure 1. Ustekinumab durability by week 8 serum drug level Funding Agencies CIHR

A264 IDENTIFYING CLINICAL PREDICTORS FOR SUCCESS OF EXCLUSIVE ENTERAL NUTRITION INDUCTION THERAPY IN PEDIATRIC CROHN DISEASE

Abstract Background Current treatments for IBD focus on reducing inflammation, mostly through suppression of the immune system. Exclusive enteral nutrition (EEN) is recognized as the first line therapy for mild-to-moderate luminal pediatric Crohn disease patients pCD. Although EEN is safe, as it does not suppress the immune system, it poses considerable challenges to patients, mostly due to palatability and monotony of the formula and treatment costs. Moreover, the efficacy of EEN varies greatly from patient to patient. Therefore, there is a need to distinguish between responders and non-responder patients. Aims Identify clinical features associated with efficacy of EEN induction therapy and apply machine learning to build a classifier to identify EEN non-responders. Methods The Canadian Children Inflammatory Bowel Disease Network prospectively enrolled and followed new onset pediatric IBD cases. Prospective data for 308 pCD with EEN as their first treatment for CD are available. Patients with weighted Pediatric CD Activity Indexes (wPCDAI) collected after at least 4 weeks on EEN were compiled into a dataset (n=108). For this analysis, treatment response was defined as a wPCDAI reduction of at least 12.5 points of a patient’s wPCDAI baseline score. The dataset includes 26 features for each of the 108 pCD patients at time of diagnosis. This included blood test results (Hgb, ESR, CRP, Alb, Htc, Plt), Paris Classifications, height, and weight Z-scores, as well as wPCDAI, SES-CD (simple endoscopic score, CD), PGA (physician global assessment), and Mayo scores. Odds ratios were calculated to determine whether any features were associated with response to EEN induction therapy. Then, the most relevant features were identified with regularization techniques and a machine learning classifier for predicting response to EEN was built. Results Results showed that the appropriate subset of features to include for optimal accuracy over model simplicity are n=4 (PUCAI, PGA, SES-CD scores, and hematocrit). Also, an increase in PGA score (e.g., moving from “mild disease” to “moderate disease”) was associated with an increase in the chance of EEN failure (OR 3.1, 95% CI [1.7,5.8], p=0.0001). The best classifier for predicting EEN response was a random forest consisting of 20 decision trees. The classifier achieved an area under the ROC curve of 0.75 ± 0.07 Conclusions Our results suggest that it is possible to produce a classifier capable of predicting EEN clinical remission with an accuracy over 60%. Higher PGA, PUCAI, and SES-CD scores show potential for predicting patients less likely to respond to EEN induction. This research has the potential to provide better quality of life for children who live with IBD. Funding Agencies CIHRIMAGINE SPOR Network , Women and Children's Health Research Institute

Disordered eating behaviors in pediatric patients with inflammatory bowel disease in remission or mild-moderate disease activity.

Inflammatory bowel disease (IBD) is a chronic, autoimmune disorder that affects the gastrointestinal tract. Disordered eating describes irregular eating behaviors that may be a precursor to an eating disorder diagnosis. Higher rates of disordered eating have been described in chronic diseases. Screening for disordered eating is not performed in pediatric patients with IBD. The goal of this longitudinal study was to use the Eating Attitudes Test (EAT-26) to screen pediatric patients with IBD for disordered eating, estimate our population's prevalence, identify potential risk factors, and correlate positive EAT-26 screen results with evaluation in adolescent medicine clinic. Eighty patients with IBD between 10 and 21 years completed the EAT-26 questionnaire during gastroenterology clinic visit. Disease activity was measured using Pediatric Ulcerative Colitis Activity Index (PUCAI) and Pediatric Crohn's Disease Activity Index (PCDAI). Patients also rated their own disease activity on a numerical scale. Five patients had a positive EAT-26 screen and were evaluated in the adolescent medicine clinic. One hundred percent of those who screened positive were diagnosed with a concomitant eating disorder once evaluated. Only 20% of those who screened positive had active IBD. Higher weight, body mass index, and patient perception of disease activity were associated with increased EAT-26 score. Pediatric patients with IBD are at risk for disordered eating, with a prevalence of 6% in our population, which is twice the prevalence of disordered eating in the general population. The EAT-26 questionnaire is a feasible tool to screen pediatric IBD patients for disordered eating.