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

INTRODUCTION: 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). METHODS: 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. RESULTS: 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. DISCUSSION: 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.

Diagnosis change in pediatric inflammatory bowel disease.

OBJECTIVES: This study aims to characterize pediatric inflammatory bowel disease (IBD) patients who change diagnosis and describe the characteristics of that change. METHODS: A retrospective study was conducted on pediatric IBD patients from the ImproveCareNow (ICN) multicenter international cohort from 2007 to January 2019. Primary outcome was change in diagnosis after the first four visits. Other variables included demographics, diagnostics, disease characteristics, and timing. RESULTS: 6.1% of 18,055 patients aged 1-20 years changed diagnosis. Median time between the baseline visit and first diagnosis change was 0.9 years. Change in diagnosis occurred in 257/12,178 (2.1%) patients with Crohn's disease (CD), 347/4758 (7.3%) patients with ulcerative colitis (UC), and 495/1119 (44.2%) patients with IBD-Unclassified (IBD-U). In multivariable analysis, initial diagnosis of IBD-U and longer follow-up times were associated with greater odds of a diagnosis change. CONCLUSION: IBD-U initial diagnosis and longer follow-up were associated with increased diagnosis change risk. The most common change was reclassification to CD. Disease activity, moderate malnutrition, and presence of EIMs were not associated with change in diagnosis.

Conceptualizing and redefining successful patient engagement in patient advisory councils in learning health networks.

Introduction: Patient engagement has historically referenced engagement in one's healthcare, with more recent definitions expanding patient engagement to encompass patient advocacy work in Learning Health Networks (LHNs). Efforts to conceptualize and define what patient engagement means-and what successful patient engagement means-are, however, lacking and a barrier to meaningful and sustainable patient engagement via patient advisory councils (PACs) across LHNs. Methods: Several co-authors (Madeleine Huwe, Becky Woolf, Jennie David) are former ImproveCareNow (ICN) PAC members, and we integrate a narrative review of the extant literature and a case study of our lived experiences as former ICN PAC members. We present nuanced themes of successful patient engagement from our lived experiences on ICN's PAC, with illustrative quotes from other PAC members, and then propose themes and metrics to consider in patient engagement across LHNs. Results: Successful patient engagement in our experiences with ICN's PAC reaches beyond the "levels of engagement" previously described in the literature. We posit that our successful patient/PAC engagement experiences with ICN represent key mechanisms that could be applied across LHNs, including (1) personal growth for PAC members, (2) PAC internal engagement/community, (3) PAC engagement and presence within the LHN, (4) local institutional engagement for those who participate in the LHN, and (5) tangible resources/products from PAC members. Conclusion: Patient engagement in LHNs, like ICN, holds significant power to meaningfully shape and co-produce healthcare systems, and engagement is undervalued and conceptualized dichotomously (eg, engaged or not engaged). Reconceptualizing successful patient/PAC engagement is critical in ongoing efforts to study, support, and understand mechanisms of sustainable and successful patient engagement. Having a modern, multidimensional definition for successful patient engagement in LHNs can support efforts to increase underrepresented voices in PACs, measure and track successful multidimensional patient engagement, and study how successful patient engagement may impact outcomes for patients and LHNs.

Variability of Psychosocial Services Within the ImproveCareNow Learning Health System: Opportunities for Optimization.

Care for youth with pediatric inflammatory bowel disease (IBD) is the focus of ImproveCareNow (ICN), an international learning health system devoted to quality care and improved outcomes through collaboration, data sharing, and research. Known to be significantly disruptive to normative social development and quality of life, pediatric IBD significantly increases the risk of internalizing distress and secondary developmental sequelae. While multidisciplinary support including psychosocial care (from social workers and pediatric psychologists) is growing, this evidence-based and beneficial set of services is not universally available to youth with IBD. In a survey sent to the more than 100 established ICN centers, psychosocial providers attempted to identify the coverage and practice scope of psychosocial providers within the network. Results indicated that support varies widely by service type and availability of providers. Recommendations for further research and considerations for centers seeking to expand supports are considered.

Using multiple imputation of real-world data to estimate clinical remission in pediatric inflammatory bowel disease.

Aim: To evaluate the performance of the multiple imputation (MI) method for estimating clinical effectiveness in pediatric Crohn's disease in the ImproveCareNow registry; to address the analytical challenge of missing data. Materials & methods: Simulation studies were performed by creating missing datasets based on fully observed data from patients with moderate-to-severe Crohn's disease treated with non-ustekinumab biologics. MI was used to impute sPCDAI remission statuses in each simulated dataset. Results: The true remission rate (75.1% [95% CI: 72.6%, 77.5%]) was underestimated without imputation (72.6% [71.8%, 73.3%]). With MI, the estimate was 74.8% (74.4%, 75.2%). Conclusion: MI reduced nonresponse bias and improved the validity, reliability, and efficiency of real-world registry data to estimate remission rate in pediatric patients with Crohn's disease.

Use, Durability, and Risks for Discontinuation of Initial and Subsequent Biologics in a Large Pediatric-Onset IBD Cohort.

BACKGROUND: Biologic medications are recommended for treatment of moderately-to-severely active Crohn disease (CD) or ulcerative colitis (UC) in children. However, many patients require sequential biologic treatment because of nonresponse or loss of response to the initial biologic. METHODS: We analyzed pediatric inflammatory bowel disease (IBD) data from the ImproveCareNow Network registry between May 2006 and September 2016, including time to biologic initiation, choice of first subsequent biologics, biologic durability, and reasons for discontinuation. RESULTS: Of 17,649 patients with IBD [CD: 12,410 (70%); UC: 5239 (30%)], 7585 (43%) were treated with a biologic agent before age 18 (CD: 50%; UC: 25%). Biologic treatment was more likely for CD than UC (odds ratio, 3.0; 95% CI: 2.8-3.2; P < 0.0001). First biologic agents for all patients were anti-tumor necrosis factor agents (88% infliximab, 12% adalimumab). Probability of remaining on the first biologic was significantly higher in CD than UC ( P < 0.0001). First biologics were discontinued because of loss of response (39%), intolerance (23%), and nonresponse (19%). In univariate analysis, factors associated with discontinuation of first and/or second biologics in CD include colonic-only disease, corticosteroid use, upper gastrointestinal tract involvement, and clinical and biochemical markers of severe disease. Biologic durability improved with later induction date. CONCLUSIONS: Treatment with biologic medications is common in pediatric IBD. Patients with CD are more likely to receive biologics, receive biologics earlier in disease course, and remain on the first biologic longer than patients with UC. Multiple factors may predict biologic durability in children with IBD.

Toward an ontology of collaborative learning healthcare systems.

Objective: To establish a basis for a domain ontology - a formal, explicit specification of a shared conceptualization - of collaborative learning healthcare systems (CLHSs) in order to facilitate measurement, explanation, and improvement. Methods: We adapted the "Methontology" approach to begin building an ontology of CLHSs. We specified the purpose of an ontology, acquired domain knowledge via literature review, conceptualized a common framework of CLHSs using a grounded approach, refined these concepts based on expert panel input, and illustrated concept application via four cases. Results: The set of concepts identified as important to include in an ontology includes goals, values, structure, actors, environment, and products. To establish this set of concepts, we gathered input from content experts in two ways. First, expert panel methods were used to elicit feedback on these concepts and to test the elicitation of terms for the vocabulary of the Values concept. Second, from these discussions we developed a mapping exercise to test the intuitiveness of the concepts, requesting that network leaders from four CLHSs complete a mapping exercise to associate characteristics of their networks with the high-level concepts, building the vocabulary for each concept in a grounded fashion. We also solicited feedback from these participants on the experience of completing the mapping exercise, finding that the exercise is acceptable and could aid in CLHS development and collaboration. Respondents identified opportunities to improve the operational definitions of each concept to ensure that corresponding vocabularies are distinct and non-overlapping. Discussion: Our results provide a foundation for developing a formal, explicit shared conceptualization of CLHSs. Once developed, such a tool can be useful for measurement, explanation, and improvement. Further work, including alignment to a top-level ontology, expanding the vocabulary, and defining relations between vocabulary is required to formally build out an ontology for these uses.

Personalized Research on Diet in Ulcerative Colitis and Crohn's Disease: A Series of N-of-1 Diet Trials.

INTRODUCTION: Evidence about specific carbohydrate diet (SCD) for inflammatory bowel disease (IBD) is limited. We conducted 54 single-subject, double-crossover N-of-1 trials comparing SCD with a modified SCD (MSCD) and comparing each with the participant's baseline, usual diet (UD). METHODS: Across 19 sites, we recruited patients aged 7-18 years with IBD and active inflammation. Following a 2-week baseline (UD), patients were randomized to 1 of 2 sequences of 4 alternating 8-week SCD and MSCD periods. Outcomes included fecal calprotectin and patient-reported symptoms. We report posterior probabilities from Bayesian models comparing diets. RESULTS: Twenty-one (39%) participants completed the trial, 9 (17%) completed a single crossover, and 24 (44%) withdrew. Withdrawal or early completion occurred commonly (lack of response [n = 11], adverse events [n = 11], and not desiring to continue [n = 6]). SCD and MSCD performed similarly for most individuals. On average, there was <1% probability of a clinically meaningful difference in IBD symptoms between SCD and MSCD. The average treatment difference was -0.3 (95% credible interval -1.2, 0.75). There was no significant difference in the ratio of fecal calprotectin geometric means comparing SCD and MSCD (0.77, 95% credible interval 0.51, 1.10). Some individuals had improvement in symptoms and fecal calprotectin compared with their UD, whereas others did not. DISCUSSION: SCD and MSCD did not consistently improve symptoms or inflammation, although some individuals may have benefited. However, there are inherent difficulties in examining dietary changes that complicate study design and ultimately conclusions regarding effectiveness.

Whole-genome sequencing of African Americans implicates differential genetic architecture in inflammatory bowel disease.

Whether or not populations diverge with respect to the genetic contribution to risk of specific complex diseases is relevant to understanding the evolution of susceptibility and origins of health disparities. Here, we describe a large-scale whole-genome sequencing study of inflammatory bowel disease encompassing 1,774 affected individuals and 1,644 healthy control Americans with African ancestry (African Americans). Although no new loci for inflammatory bowel disease are discovered at genome-wide significance levels, we identify numerous instances of differential effect sizes in combination with divergent allele frequencies. For example, the major effect at PTGER4 fine maps to a single credible interval of 22 SNPs corresponding to one of four independent associations at the locus in European ancestry individuals but with an elevated odds ratio for Crohn disease in African Americans. A rare variant aggregate analysis implicates Ca2+-binding neuro-immunomodulator CALB2 in ulcerative colitis. Highly significant overall overlap of common variant risk for inflammatory bowel disease susceptibility between individuals with African and European ancestries was observed, with 41 of 241 previously known lead variants replicated and overall correlations in effect sizes of 0.68 for combined inflammatory bowel disease. Nevertheless, subtle differences influence the performance of polygenic risk scores, and we show that ancestry-appropriate weights significantly improve polygenic prediction in the highest percentiles of risk. The median amount of variance explained per locus remains the same in African and European cohorts, providing evidence for compensation of effect sizes as allele frequencies diverge, as expected under a highly polygenic model of disease.

Development and Testing of a New Simplified Endoscopic Mucosal Assessment for Crohn's Disease: The SEMA-CD.

OBJECTIVES: Endoscopic mucosal improvement is the gold standard for assessing treatment efficacy in clinical trials of Crohn's disease. Current endoscopic indices are not routinely used in clinical practice. The lack of endoscopic information in large clinical registries limits their use for research. A quick, easy, and accurate method is needed for assessing mucosal improvement for clinicians in real-world practice. We developed and tested a novel simplified endoscopic mucosal assessment for Crohn's disease (SEMA-CD). METHODS: We developed a 5-point scale for ranking endoscopic severity of ileum and colon based on Simple Endoscopic Score for Crohn's disease (SES-CD). Central readers were trained to perform SES-CD and SEMA-CD. Pediatric patients with Crohn's disease undergoing colonoscopy were enrolled. Video recordings of colonoscopies were de-identified and randomly assigned to blinded central readers. The SES-CD and SEMA-CD were scored for each video. The SES-CD was considered the validated standard for comparison. Correlation was assessed with Spearman rho, inter- and intrarater reliability with kappa statistics. RESULTS: Fifty-seven colonoscopies were read a total of 212 times. Correlation between SEMA-CD and SES-CD was strong (rho = 0.98, P < 0.0001). Inter-rater reliability for SEMA-CD was 0.80, and intrarater reliability was 0.83. Central readers rated SEMA-CD as easier than SES-CD. CONCLUSION: The SEMA-CD accurately and reproducibly correlates with the standard SES-CD. Central readers viewed SEMA-CD as easier than SES-CD. Use of SEMA-CD in practice should enable collecting mucosal improvement information in large populations of patients. This will improve the quality of research that can be conducted in clinical registries. External validation is needed.

Transition to Adult IBD Care: A Pilot Multi-Site, Telehealth Hybrid Intervention.

OBJECTIVE: Transition to adult IBD care continues to be a challenge. Efficacious models of improving transition to adult care in the United States are lacking. We present data from a pilot, prospective, non-randomized, intervention implemented at IBD centers in the Midwest and Southeast United States. DESIGN AND METHODS: Adolescents and young adults (AYAs; 16-20 years) with IBD and their parents completed a 4- to 5-month transition program (1 in-person group session; 4 individual telehealth sessions). Primary outcomes were feasibility (i.e., recruitment, retention, fidelity) and acceptability (i.e., program satisfaction). Secondary outcomes were changes in transition readiness, self-management skill acquisition, perceived readiness to transfer to adult care, and disease knowledge. RESULTS: The study exceeded goals for recruitment (target N = 20; actual: 36) and retention (target: 80%; actual: 86.11%). On average, it took participants 20.91 ± 3.15 weeks to complete our 4- to 5-month intervention and there were no deviations from the study protocol. Participant ratings for overall program satisfaction, perceived helpfulness, and program length and format were positive. Increases in transition readiness, t(30) = 8.30, d = 1.49, p < .001, self-management skill acquisition, t(30) = 3.93, d = 0.70, p < .001, and disease knowledge, t(30) = 8.20, d = 1.58, p < .001 were noted. AYA- and parent-perceived transfer readiness also improved (p's < .05; d's = 0.76-1.68). CONCLUSIONS: This article presents feasibility and acceptability data for a 4- to 5-month transition intervention. Improvements in AYA transition readiness, self-management skill acquisition, IBD knowledge, and AYA/parent perceived transfer readiness were also observed.

Technology-Enabled Health Care Collaboration in Pediatric Chronic Illness: Pre-Post Interventional Study for Feasibility, Acceptability, and Clinical Impact of an Electronic Health Record-Linked Platform for Patient-Clinician Partnership.

BACKGROUND: Mobile health (mHealth) technology has the potential to support the Chronic Care Model's vision of closed feedback loops and patient-clinician partnerships. OBJECTIVE: This study aims to evaluate the feasibility, acceptability, and short-term impact of an electronic health record-linked mHealth platform (Orchestra) supporting patient and clinician collaboration through real-time, bidirectional data sharing. METHODS: We conducted a 6-month prospective, pre-post, proof-of-concept study of Orchestra among patients and parents in the Cincinnati Children's Hospital inflammatory bowel disease (IBD) and cystic fibrosis (CF) clinics. Participants and clinicians used Orchestra during and between visits to complete and view patient-reported outcome (PRO) measures and previsit plans. Surveys completed at baseline and at 3- and 6-month follow-up visits plus data from the platform were used to assess outcomes including PRO completion rates, weekly platform use, disease self-efficacy, and impact on care. Analyses included descriptive statistics; pre-post comparisons; Pearson correlations; and, if applicable, effect sizes. RESULTS: We enrolled 92 participants (CF: n=52 and IBD: n=40), and 73% (67/92) completed the study. Average PRO completion was 61%, and average weekly platform use was 80%. Participants reported improvement in self-efficacy from baseline to 6 months (7.90 to 8.44; P=.006). At 6 months, most participants reported that the platform was useful (36/40, 90%) and had a positive impact on their care, including improved visit quality (33/40, 83%), visit collaboration (35/40, 88%), and visit preparation (31/40, 78%). PRO completion was positively associated with multiple indicators of care impact at 3 and 6 months. CONCLUSIONS: Use of an mHealth tool to support closed feedback loops through real-time data sharing and patient-clinician collaboration is feasible and shows indications of acceptability and promise as a strategy for improving pediatric chronic illness management.

Acute pancreatitis in children: Updates in epidemiology, diagnosis and management.

Acute pancreatitis (AP), manifesting as acute onset of abdominal pain, vomiting, and nausea, is increasingly being recognized in children secondary to increased awareness, more identifiable etiologies as well as advances in diagnostic capabilities, like imaging. Despite this increased awareness and ability for more frequent diagnoses, the natural history of AP remains poorly understood leading to gaps in approach and management, especially in children. Coupled with poor epidemiologic and management awareness, there remains a lack of understanding of the long term implications of severe acute pancreatitis (SAP). Hence, the role of the primary care clinician in the early diagnosis, and management, remains critical and may affect the need for consultation with pediatric sub-specialists like gastroenterologists. This review provides guidelines regarding epidemiology, diagnosis, and management strategies to address some of these gaps.

Updates in diagnosis and management of inflammatory bowel disease.

Worldwide incidence of inflammatory bowel disease (IBD) is stable in developed countries, but rising in developing countries. Presenting symptoms of IBD can be highly variable. New imaging modalities, a greater armamentarium of therapeutic options, and a greater understanding of complication risks have changed the diagnosis and management of pediatric inflammatory bowel diseases. Effective teamwork among those who care for pediatric patients with IBD minimizes complications and maximizes desired outcomes.

Fecal Markers of Inflammation and Disease Activity in Pediatric Crohn Disease: Results from the ImageKids Study.

BACKGROUND: Noninvasive and accurate methods to monitor inflammatory bowel disease are required. As a planned ancillary study of the prospective ImageKids cohort, we aimed to assess the performance of fecal calprotectin (FC) with comparison to 3 fecal inflammatory markers; S100A12 (FA12), tumor pyruvate kinase isoenzyme type M2 (FM2PK) and fecal osteoprotegerin (FOPG) as indicators of a number of disease characteristics. METHODS: The ImageKids study was a multicenter study designed to develop 2 magnetic resonance enterography-based measures for children with Crohn disease (6-18 years old). All patients underwent magnetic resonance enterography, a complete ileocolonoscopic evaluation and provided a fecal sample. Fecal samples were assay for FC, FA12, FM2PK, and FOPG by ELISA. RESULTS: One-hundred fifty-six children provided 190 fecal samples. Median (interquartile range) for fecal makers were FC, 602 (181-1185) µg/g; FA12, 21 (3-109) µg/g; FM2PK, 16 (2-20) U/mL; and FOPG, 125 (125-312) µg/g. All markers correlated with simple endoscopic severity index for Crohn disease and with other constructs of disease activity, but FC had the highest overall correlations. FA12, however, predicted mucosal healing with significantly higher specificity (87% vs 70%, P = 0.004) and equivalent sensitivity (91% vs 90%) compared to FC. CONCLUSION: This study has confirmed that FC is useful, and overall best, marker to monitor mucosal inflammation in inflammatory bowel disease. FA12, however, appears to be a more suitable maker for prediction of mucosal healing in children.

Evaluating the Comparative Effectiveness of Two Diets in Pediatric Inflammatory Bowel Disease: A Study Protocol for a Series of N-of-1 Trials.

Inflammatory bowel disease (IBD) affects 3 million children and adults in the US. Treatment involves medications with considerable risk profiles. Dietary modification, such as the specific carbohydrate diet (SCD), may be helpful in treating IBD, but there is insufficient evidence of its effectiveness. N-of-1 trials are ideal for addressing this important research question. The Personalized Research on Diet in Ulcerative Colitis and Crohn's Disease (PRODUCE) study employs a series of 50 individual N-of-1 trials that compare the SCD to a modified SCD. Treatment periods are assigned in blocks of two, with each patient completing two balanced treatment blocks. Patients are randomized to start with the SCD or modified SCD and alternate between conditions for four eight-week periods. A mobile app guides collecting and viewing data, transitioning diets, and reviewing personal results. Primary outcomes include patient reported outcomes (PROs) of stool frequency, stool consistency, pain interference, and gastrointestinal (GI) symptom severity. We examine changes in inflammation via fecal calprotectin. Participants will receive a personalized answer regarding comparative effectiveness between the SCD and a less restrictive diet option (modified SCD), as well as compared to their baseline diet. We will aggregate the results of completed N-of-1 trials across patients to estimate population level comparative effectiveness of these treatments and the effectiveness of each diet.

Improving IBD Transition, Self-management, and Disease Outcomes With an In-clinic Transition Coordinator.

OBJECTIVES: Deficits in the preparation of patients with inflammatory bowel disease (IBD) who are transitioning to adult care are known yet studies presenting outcome data of transition interventions in IBD are lacking. We present data evaluating the impact of a transition coordinator on behavioral and clinical transition outcomes. METHODS: A retrospective chart review identified 135 patients who had met with our transition coordinator and completed the Transition Readiness Assessment Questionnaire before, and 1 year after, the intervention. Changes in transition readiness, self-management skill acquisition, and clinical outcomes (eg, number of patients transferred vs "bounced back" to pediatrics, percentage of patients over age 21, changes in disease remission) were examined and compared with patients who received no intervention. RESULTS: Intervention participants demonstrated a significant increase in transition readiness, F(1, 134) = 24.34, P < 0.001, and self-management skill acquisition, F(1, 134) = 5.61, P < 0.05. The percentage of patients in remission significantly increased from pre- to post-intervention, χ(134) = 9.03, P < 0.01. There were no significant changes in the comparison population (Ps > 0.05). Following implementation of our programming, the percentage of patients over age 21 decreased by 33.07%. CONCLUSIONS: A 1-time transition coordinator-led intervention improved adolescent transition readiness and acquisition of self-management skills. The proportion of young adult patients retained in pediatric care was reduced. Benefits of hiring a transition coordinator are discussed.

Decreased Fecal Bacterial Diversity and Altered Microbiome in Children Colonized With Clostridium difficile.

OBJECTIVES: The gut microbiome is believed to play a role in the susceptibility to and treatment of Clostridium difficile infections (CDIs). It is, however, unknown whether the gut microbiome is also affected by asymptomatic C difficile colonization. Our study aimed to evaluate the fecal microbiome of children based on C difficile colonization, and CDI risk factors, including antibiotic use and comorbid inflammatory bowel disease (IBD). METHODS: Subjects with IBD and non-IBD controls were prospectively enrolled from pediatric clinics for a biobanking project (n = 113). A fecal sample was collected from each subject for research purposes only and was evaluated for asymptomatic toxigenic C difficile colonization. Fecal microbiome composition was determined by 16S rRNA sequencing. RESULTS: We found reduced bacterial diversity and altered microbiome composition in subjects with C difficile colonization, concurrent antibiotic use, and/or concomitant IBD (all P < 0.05). Accounting for antibiotic use and IBD status, children colonized with C difficile had significant enrichment in taxa from the genera Ruminococcus, Eggerthella, and Clostridium. Children without C difficile had increased relative abundances of Faecalibacterium and Rikenellaceae. Imputed metagenomic functions of those colonized were enriched for genes in oxidative phosphorylation and beta-lactam resistance, whereas in the subjects without C difficile, several functions in translation and metabolism were over-represented. CONCLUSIONS: In children, C difficile colonization, or factors that predispose to colonization such as antibiotic use and IBD status were associated with decreased gut bacterial diversity and altered microbiome composition. Averting such microbiome alterations may be a method to prevent or treat CDI.