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Background and AimsWe aimed to determine whether a targeted gene expression panel could predict clinical outcomes in paediatric ulcerative colitis [UC] and investigated putative pathogenic roles of predictive genes.MethodsIn total, 313 rectal RNA samples from a cohort of newly diagnosed paediatric UC patients (PROTECT) were analysed by a real-time PCR microfluidic array for expression of type 1, 2 and 17 inflammation genes. Associations between expression and clinical outcomes were assessed by logistic regression. Identified prognostic markers were further analysed using existing RNA sequencing (RNA-seq) data sets and tissue immunostaining.ResultsIL13RA2 was associated with a lower likelihood of corticosteroid-free remission (CSFR) on mesalamine at week 52 (p = .002). A model including IL13RA2 and only baseline clinical parameters was as accurate as an established clinical model, which requires week 4 remission status. RORC was associated with a lower likelihood of colectomy by week 52. A model including RORC and PUCAI predicted colectomy by 52 weeks (area under the receiver operating characteristic curve 0.71). Bulk RNA-seq identified IL13RA2 and RORC as hub genes within UC outcome-associated expression networks related to extracellular matrix and innate immune response, and lipid metabolism and microvillus assembly, respectively. Adult UC single-cell RNA-seq data revealed IL13RA2 and RORC co-expressed genes were localized to inflammatory fibroblasts and undifferentiated epithelial cells, respectively, which was supported by protein immunostaining.ConclusionTargeted assessment of rectal mucosal immune gene expression predicts 52-week CSFR in treatment-naïve paediatric UC patients. Further exploration of IL-13Rɑ2 as a therapeutic target in UC and future studies of the epithelial-specific role of RORC in UC pathogenesis are warranted.

Summary An important goal of clinical genomics is to be able to estimate the risk of adverse disease outcomes. Between 5% and 10% of individuals with ulcerative colitis (UC) require colectomy within 5 years of diagnosis, but polygenic risk scores (PRSs) utilizing findings from genome-wide association studies (GWASs) are unable to provide meaningful prediction of this adverse status. By contrast, in Crohn disease, gene expression profiling of GWAS-significant genes does provide some stratification of risk of progression to complicated disease in the form of a transcriptional risk score (TRS). Here, we demonstrate that a measured TRS based on bulk rectal gene expression in the PROTECT inception cohort study has a positive predictive value approaching 50% for colectomy. Single-cell profiling demonstrates that the genes are active in multiple diverse cell types from both the epithelial and immune compartments. Expression quantitative trait locus (QTL) analysis identifies genes with differential effects at baseline and week 52 follow-up, but for the most part, differential expression associated with colectomy risk is independent of local genetic regulation. Nevertheless, a predicted polygenic transcriptional risk score (PPTRS) derived by summation of transcriptome-wide association study (TWAS) effects identifies UC-affected individuals at 5-fold elevated risk of colectomy with data from the UK Biobank population cohort studies, independently replicated in an NIDDK-IBDGC dataset. Prediction of gene expression from relatively small transcriptome datasets can thus be used in conjunction with TWASs for stratification of risk of disease complications.

Background Develop a clinical and biological predictive model for colectomy risk in children newly diagnosed with ulcerative colitis (UC). Methods This was a multicenter inception cohort study of children (ages 4-17 years) newly diagnosed with UC treated with standardized initial regimens of mesalamine or corticosteroids (CS) depending upon initial disease severity. Therapy escalation to immunomodulators or infliximab was based on predetermined criteria. Patients were phenotyped by clinical activity per the Pediatric Ulcerative Colitis Activity Index (PUCAI), disease extent, endoscopic/histologic severity, and laboratory markers. In addition, RNA sequencing defined pretreatment rectal gene expression and high density DNA genotyping by the Affymetrix UK Biobank Axiom Array. Coprimary outcomes were colectomy over 3 years and time to colectomy. Generalized linear models, Cox proportional hazards multivariate regression modeling, and Kaplan-Meier plots were used. Results Four hundred twenty-eight patients (mean age 13 years) started initial theapy with mesalamine (n = 136), oral CS (n = 144), or intravenous CS (n = 148). Twenty-five (6%) underwent colectomy at ≤1 year, 33 (9%) at ≤2 years, and 35 (13%) at ≤3 years. Further, 32/35 patients who had colectomy failed infliximab. An initial PUCAI ≥ 65 was highly associated with colectomy (P = 0.0001). A logistic regression model predicting colectomy using the PUCAI, hemoglobin, and erythrocyte sedimentation rate had a receiver operating characteristic area under the curve of 0.78 (95% confidence interval [0.73, 0.84]). Addition of a pretreatment rectal gene expression panel reflecting activation of the innate immune system and response to external stimuli and bacteria to the clinical model improved the receiver operating characteristic area under the curve to 0.87 (95% confidence interval [0.82, 0.91]). Conclusions A small group of children newly diagnosed with severe UC still require colectomy despite current therapies. Our gene signature observations suggest additional targets for management of those patients not responding to current medical therapies.

Background Proactively monitoring infliximab levels is an emerging area of interest in pediatric Crohn’s disease. There are only limited data on therapeutic drug monitoring for children with Crohn’s disease. The goal of our study was to determine the utility of therapeutic drug monitoring in achieving clinical remission in a cohort of pediatric Crohn’s disease patients receiving infliximab. Methods This prospective single-center study enrolled 37 patients with Crohn’s disease at the start of infliximab infusions and monitored trough levels at 6-month intervals for 18 months. Each participant was matched to a historic control for the modified pediatric Crohn’s disease activity index (mPCDAI) at baseline, age and sex. The primary outcome was an mPCDAI score of ≤7.5 at 6, 12 and 18 months. A multivariate logistic regression analysis was performed. Results Data were available for all 37 cases at 6 and 12 months and for 34 cases at 18 months. Demographics and disease characteristics were similar between groups. All 34 cases demonstrated clinical remission at 18 months (100% vs. 88%, P=0.114). Univariate and multivariate analyses did not show statistical significance. Dose intensification was seen more often in the cases at 18 months. Conclusion All of our moderate-to-severe pediatric Crohn’s disease patients who received prospective therapeutic drug monitoring of infliximab were in clinical remission at follow up, but this was not statistically significantly different from the 88% clinical remission rate of the control group.

SUMMARYAn important goal of clinical genomics is to be able to estimate the risk of adverse disease outcomes. Between 5% and 10% of ulcerative colitis (UC) patients require colectomy within five years of diagnosis, but polygenic risk scores (PRS) utilizing findings from GWAS are unable to provide meaningful prediction of this adverse status. By contrast, in Crohn’s disease, gene expression profiling of GWAS-significant genes does provide some stratification of risk of progression to complicated disease in the form of a Transcriptional Risk Score (TRS). Here we demonstrate that both measured (TRS) and polygenic predicted gene expression (PPTRS) identify UC patients at 5-fold elevated risk of colectomy with data from the PROTECT clinical trial and UK Biobank population cohort studies, independently replicated in an NIDDK-IBDGC dataset. Prediction of gene expression from relatively small transcriptome datasets can thus be used in conjunction with transcriptome-wide association studies to stratify risk of disease complications.

Background The incidence of very early onset inflammatory bowel disease (VEOIBD) is increasing, yet the phenotype and natural history of VEOIBD are not well described. Methods We performed a retrospective cohort study of patients diagnosed with VEOIBD (6 years of age and younger) between 2008 and 2013 at 25 North American centers. Eligible patients at each center were randomly selected for chart review. We abstracted data at diagnosis and at 1, 3, and 5 years after diagnosis. We compared the clinical features and outcomes with VEOIBD diagnosed younger than 3 years of age with children diagnosed with VEOIBD at age 3 to 6 years. Results The study population included 269 children (105 [39%] Crohn’s disease, 106 [39%] ulcerative colitis, and 58 [22%] IBD unclassified). The median age of diagnosis was 4.2 years (interquartile range 2.9–5.2). Most (94%) Crohn’s disease patients had inflammatory disease behavior (B1). Isolated colitis (L2) was the most common disease location (70% of children diagnosed younger than 3 years vs 43% of children diagnosed 3 years and older; P = 0.10). By the end of follow-up, stricturing/penetrating occurred in 7 (6.6%) children. The risk of any bowel surgery in Crohn’s disease was 3% by 1 year, 12% by 3 years, and 15% by 5 years and did not differ by age at diagnosis. Most ulcerative colitis patients had pancolitis (57% of children diagnosed younger than 3 years vs 45% of children diagnosed 3 years and older; P = 0.18). The risk of colectomy in ulcerative colitis/IBD unclassified was 0% by 1 year, 3% by 3 years, and 14% by 5 years and did not differ by age of diagnosis. Conclusions Very early onset inflammatory bowel disease has a distinct phenotype with predominantly colonic involvement and infrequent stricturing/penetrating disease. The cumulative risk of bowel surgery in children with VEOIBD was approximately 14%–15% by 5 years. These data can be used to provide anticipatory guidance in this emerging patient population.

BACKGROUND: The genetic contributions to pediatric onset ulcerative colitis (UC), characterized by severe disease and extensive colonic involvement, are largely unknown. In adult onset UC, Genome Wide Association Study (GWAS) has identified numerous loci, most of which have a modest susceptibility risk (OR 0.84–1.14), with the exception of the human leukocyte antigen (HLA) region on Chromosome 6 (OR 3.59). METHOD: To study the genetic contribution to exclusive pediatric onset UC, a GWAS was performed on 466 cases with 2099 healthy controls using UK Biobank array. SNP2HLA was used to impute classical HLA alleles and their corresponding amino acids, and the results are compared with adult onset UC. RESULTS: HLA explained the almost entire association signal, dominated with 191 single nucleotide polymorphisms (SNPs) (p = 5 x 10(-8) to 5 x 10(-10)). Although very small effects, established SNPs in adult onset UC loci had similar direction and magnitude in pediatric onset UC. SNP2HLA imputation identified HLA-DRB1*0103 (odds ratio [OR] = 6.941, p = 1.92*10(–13)) as the most significant association for pediatric UC compared with adult onset UC (OR = 3.59). Further conditioning showed independent effects for HLA-DRB1*1301 (OR = 2.25, p = 7.92*10(–9)) and another SNP rs17188113 (OR = 0.48, p = 7.56*10(–9)). Two HLA-DRB1 causal alleles are shared with adult onset UC, while at least 2 signals are unique to pediatric UC. Subsequent stratified analyses indicated that HLA-DRB1*0103 has stronger association for extensive disease (E4: OR = 8.28, p = 4.66x10(-10)) and female gender (OR = 8.85, p = 4.82x10(-13)). CONCLUSION: In pediatric onset UC, the HLA explains almost the entire genetic associations. In addition, the HLA association is approximately twice as strong in pediatric UC compared with adults, due to a combination of novel and shared effects. We speculate the paramount importance of antigenic stimulation either by infectious or noninfectious stimuli as a causal event in pediatric UC onset.

BackgroundPrevious retrospective studies of paediatric ulcerative colitis have had limited ability to describe disease progression and identify predictors of treatment response. In this study, we aimed to identify characteristics associated with outcomes following standardised therapy after initial diagnosis.MethodsThe PROTECT multicentre inception cohort study was based at 29 centres in the USA and Canada and included paediatric patients aged 4-17 years who were newly diagnosed with ulcerative colitis. Guided by the Pediatric Ulcerative Colitis Activity Index (PUCAI), patients received initial standardised treatment with mesalazine (PUCAI 10-30) oral corticosteroids (PUCAI 35-60), or intravenous corticosteroids (PUCAI ≥65). The key outcomes for this analysis were week 12 corticosteroid-free remission, defined as PUCAI less than 10 and taking only mesalazine, and treatment escalation during the 12 study weeks to anti-tumour necrosis factor α (TNFα) agents, immunomodulators, or colectomy among those initially treated with intravenous corticosteroids. We identified independent predictors of outcome through multivariable logistic regression using a per-protocol approach. This study is registered with ClinicalTrials.gov, number NCT01536535.FindingsPatients were recruited between July 10, 2012, and April 21, 2015. 428 children initiated mesalazine (n=136), oral corticosteroids (n=144), or intravenous corticosteroids (n=148). Initial mean PUCAI was 31·1 (SD 13·3) in children initiating with mesalazine, 50·4 (13·8) in those initiating oral corticosteroids, and 66·9 (13·7) in those initiating intravenous corticosteroids (p

Background & Aims: Up to 30% of patients with Crohn's disease (CD) require surgery within the first 5 years from diagnosis. We investigated the recent risk of bowel surgery in an inception cohort of pediatric patients with CD and whether early use of biologics (tumor necrosis factor antagonists) alters later disease course. Methods: We collected data from the Pediatric Inflammatory Bowel Disease Collaborative Research Group registry on 1442 children (age, ó16 y) diagnosed with CD from January 2002 through December 2014. Data were collected at diagnosis, 30 days following diagnosis, and then quarterly and during hospitalizations for up to 12 years. Our primary aim was to determine the 10-year risk for surgery in children with CD. Our secondary aim was to determine whether early use of biologics (

Background & Aims Standard therapy for children newly diagnosed with Crohn's disease (CD) includes early administration of immunomodulators after initial treatment with corticosteroids. We compared the effectiveness of early (≤3 mo after diagnosis) treatment with an anti-tumor necrosis factor (TNF)α with that of an immunomodulator in attaining clinical remission and facilitating growth of pediatric patients. Methods We analyzed data from the RISK study, an observational research program that enrolled patients younger than age 17 diagnosed with inflammatory (nonpenetrating, nonstricturing) CD from 2008 through 2012 at 28 pediatric gastroenterology centers in North America. Patients were managed by physician dictate. From 552 children (median age, 11.8 y; 61% male; 63% with pediatric CD activity index scores >30; and median C-reactive protein level 5.6-fold the upper limit of normal), we used propensity score methodology to identify 68 triads of patients matched for baseline characteristics who were treated with early anti-TNFα therapy, early immunomodulator, or no early immunotherapy. We evaluated relationships among therapies, corticosteroid and surgery-free remission (pediatric CD activity index scores, ≤10), and growth at 1 year for 204 children. Treatment after 3 months was a covariate. Results Early treatment with anti-TNFα was superior to early treatment with an immunomodulator (85.3% vs 60.3% in remission; relative risk, 1.41; 95% confidence interval [CI], 1.14-1.75; P = .0017), whereas early immunomodulator therapy was no different than no early immunotherapy (60.3% vs 54.4% in remission; relative risk, 1.11; 95% CI, 0.83-1.48; P = .49) in achieving remission at 1 year. Accounting for therapy after 3 months, early treatment with anti-TNFα remained superior to early treatment with an immunomodulator (relative risk, 1.51; 95% CI, 1.20-1.89; P = .0004), whereas early immunomodulator therapy was no different than no early immunotherapy (relative risk, 1.00; 95% CI, 0.75-1.34; P = .99). The mean height z-score increased compared with baseline only in the early anti-TNFα group. Conclusions In children newly diagnosed with comparably severe CD, early monotherapy with anti-TNFα produced better overall clinical and growth outcomes at 1 year than early monotherapy with an immunomodulator. Further data will be required to best identify children most likely to benefit from early treatment with anti-TNFα therapy.

Budesonide (BUD) is being used in pediatric Crohn disease (CD) because it is believed to have the potential to reduce corticosteroid-related toxicity; however, few data are available describing its use. The aim of the present study was to describe BUD use in an inception cohort of pediatric patients with CD.Data were derived from the prospective Pediatric IBD Collaborative Research Group Registry established in 2002 in North America. Use of BUD in children with CD was examined.BUD was used in 119 of 932 (13%) of children with newly diagnosed CD, with 56 of 119 (47%) starting BUD ≤ 30 days of diagnosis (26/56 with ileum and/or ascending colon [IAC] disease). BUD was used as monotherapy (9%), in combination with 5-aminosalicylates (77%), or in combination with immunomodulators (43%). Forty-three percent (24/56) went on to receive conventional corticosteroid at some point following their first BUD course. For the 63 of 119 (53%) who started BUD beyond the diagnosis period, 51 of 63 (81%) also received prednisone, with BUD used as a means of weaning from prednisone in 17 of 63 (27%). Patients with IAC disease who received BUD ≤ 30 days of diagnosis were just as likely to have received conventional corticosteroids by 1 year as were those who did not receive BUD ≤ 30 days of diagnosis. Two-thirds (77/119) of patients received BUD for ≤ 6 months.BUD is being used among pediatric patients newly diagnosed as having CD, although the majority does not have disease limited to the IAC. BUD monotherapy was rare, and further data are required to better define the role of BUD in the treatment of pediatric CD.

Despite little supporting data, thiopurine use is common in pediatric ulcerative colitis (UC). Our aim was to determine outcome following thiopurine use in a multicenter inception cohort of children diagnosed with UC.Data were obtained from a prospective observational study of newly diagnosed children16 years of age. Data are recorded at diagnosis, 30 days, and quarterly. Patients are managed by physician dictates not protocol. Disease activity is classified by physician global assessment. The primary outcome was corticosteroid (CS)-free inactive UC at 1 year following thiopurine initiation without the need for rescue therapy (infliximab, calcineurin inhibitors, or colectomy).Of 1,490 patients in our registry, 394 have UC (mean age at diagnosis 11.3±3.7 years); 197 (50%) received thiopurine (49% ≤3 months from diagnosis). Also, 84% were receiving CSs and 60% 5-aminosalicylates at thiopurine start. Of the 197 patients, there was insufficient follow-up (41), previous or concomitant use of infliximab (16), or calcineurin inhibitor (7), leaving 133 patients evaluable at 1 year. Of these, 65 (49%) had CS-free inactive UC without rescue therapy. CS-free inactive disease at 1 year after initiating thiopurine was not affected by starting thiopurine ≤3 months vs.3 months from diagnosis, gender, age, or concomitant treatment with 5-aminosalicylates. Kaplan-Meier analysis showed that the likelihood of remaining free of rescue therapy in the thiopurine-treated patients was 73% at 1 year.Approximately 50% of children with UC starting thiopurine without previous or concomitant biologic or calcineurin inhibitor therapy have CS-free inactive disease 1 year later without the need for rescue therapy.

Background: We evaluated the psychometric performance of the Pediatric Ulcerative Colitis Activity Index (PUCAI) in a real-life cohort from the Pediatric IBD Collaborative Research Group. Methods: Two consecutive visits of 215 children with ulcerative colitis (UC) were included (mean age 11.2 ± 3.6 years; 112 (52%) males; 63 (29%) newly diagnosed and the others after disease duration of 24 ± 15.6 months). Validity was assessed using several constructs of disease activity. Distributional and anchor-based strategies were used to assess the responsiveness of the PUCAI to change over time following treatment. Results: Reflecting feasibility, 97.6% of 770 eligible registry visits had a completed PUCAI score versus only 47.6% for a contemporaneously collected Pediatric Crohn's Disease Activity Index (odds ratio = 45.8, 95% confidence interval [CI] 28.6–73.5) obtained for children with Crohn's disease accessioned into the same database. The PUCAI score was significantly higher in patients requiring escalation of medical therapy (45 points [interquartile range, IQR, 30–60]) versus those who did not, (0 points [IQR 0–10]; P < 0.001), and was highly correlated with physician's global assessment of disease activity (r = 0.9, P < 0.001). The best cutoff to differentiate remission from active disease was 10 points (area under receiver operating characteristic curve [AUC] 0.94; 95% CI 0.90–0.97). Test–retest reliability was excellent (intraclass correlation coefficient = 0.89; 95% CI 0.84–0.92, P < 0.001) as well as responsiveness to change (AUC 0.96 [0.92–0.99]; standardized response mean 2.66). Conclusion: This study on real-life, prospectively obtained data confirms that the PUCAI is highly feasible by virtue of the noninvasiveness, valid, and responsive index. The PUCAI can be used as a primary outcome measure to reflect disease activity in pediatric UC. (Inflamm Bowel Dis 2009)

Crohn's disease (CD) is often associated with antibodies to microbial antigens. Differences in immune response may offer clues to the pathogenesis of the disease. The aim was to examine the influence of age at diagnosis on the serologic response in children with CD.Data were drawn from 3 North American multicenter pediatric inflammatory bowel disease (IBD) research consortia. At or shortly after diagnosis, pANCA, ASCA IgA, ASCA IgG, anti-ompC, and anti-CBir1 were assayed. The results were compared as a function of age at CD diagnosis (0-7 years versus 8-15 years).In all, 705 children (798 years of age at diagnosis, 626or=8 years) were studied. Small bowel CD was less frequent in the younger group (48.7% versus 72.6%; P0.0001), while colonic involvement was comparable (91.0% versus 86.5%). ASCA IgA and IgG were seen in20% of those 0-7 years old compared to nearly 40% of those 8-15 years old (P0.001), while anti-CBir1 was more frequent in the younger children (66% versus 54%, P0.05). Anti-CBir1 detected a significant number of children in both age groups who otherwise were serologically negative. Both age at diagnosis and site of CD involvement were independently associated with expression of ASCA and anti-CBir1.Compared to children 8-15 years of age at diagnosis, those 0-7 years are more likely to express anti-CBir1 but only half as likely to express ASCA. These age-associated differences in antimicrobial seropositivity suggest that there may be different, and as yet unrecognized, genetic, immunologic, and/or microbial factors leading to CD in the youngest children.

Background: The immunomodulators (IMs) 6-mercaptopurine and azathioprine decrease corticosteroid dependence and maintain remission in Crohn's disease (CD). We describe IM use in newly diagnosed pediatric CD, comparing outcomes of “early” versus “late” initiation of therapy. Methods: Data were obtained from pediatric CD patients enrolled in a prospective, multicenter observational study. Moderate/severe disease patients treated with IM were compared for outcomes of remission, corticosteroid use, infliximab therapy, hospitalizations, and CD-related surgery based on timing of initiation of IM therapy. Results: In all, 247 children met the criteria (60% male, mean age 11.9 years); 199 were treated with IM within 1 year of diagnosis; 150 between 0–3 months (early), 49 between 3–12 months (late). Both groups showed a decrease in corticosteroid use by 12 months, at which time proportionately fewer early group patients had received corticosteroids in the preceding quarter (22%) than late groups patients (41%)(P = 0.013). The number of hospitalizations per patient was also noted to be significantly lower in the early group over the 2-year follow-up (P = 0.03). No difference was noted in the rates of remission, infliximab use over time, or surgery. Conclusions: 80% of children with newly diagnosed moderate to severe CD are treated with IM within 1 year. Early IM use is associated with reduced corticosteroid exposure and possibly fewer hospitalizations per patient. (Inflamm Bowel Dis 2008)

Background: Variation in care is a ubiquitous feature of medical practice and may lead to significant differences in health care costs, quality, and outcomes. We undertook this study to determine the extent of intercenter variation in the initial management of children newly diagnosed with Crohn’s disease. Methods: We analyzed the utilization of 5 classes of medication (immunomodulators, prednisone, antibiotics, 5-aminosalicylates, and infliximab) among 311 children with newly diagnosed Crohn’s disease followed at 10 North American pediatric gastroenterology centers. Multivariate logistic regression was used to compare the utilization rate of each class of medication at each of the 10 centers, adjusting for potential confounders including patient age, sex, race, disease severity, and anatomic location of disease. Results: Median utilization of each class of medication was: immunomodulators, 56% (range 29%–97%); prednisone, 78% (range 32%– 88%); antibiotics, 29% (range 11%– 68%); 5-aminosalicylates, 63.5% (range 18%–92%); and infliximab, 7.5% (range 3%–21%). Each of these treatments showed statistically significant intercenter variation in utilization (P 0.001 for immunomodulators, prednisone, antibiotics, and 5-ASA; P 0.02 for infliximab). After adjusting for the demographic and clinical factors listed above, intercenter variation remained significant; however, the low utilization of infliximab precluded multivariate analysis. Conclusions: Widespread intercenter variation in the medical management of newly diagnosed children with Crohn’s disease was observed, even after adjusting for possible differences in case mix between institutions. This variation may lead to unintended differences in health care costs and outcomes. (Inflamm Bowel Dis 2007;13:890 – 895)

Background The inflammatory bowel diseases (IBD) are common, complex disorders in which genetic and environmental factors are believed to interact leading to chronic inflammatory responses against the gut microbiota. Earlier genetic studies performed in mostly adult population of European descent identified 163 loci affecting IBD risk, but most have relatively modest effect sizes, and altogether explain only ~20% of the genetic susceptibility. Pediatric onset represents about 25% of overall incident cases in IBD, characterized by distinct disease physiology, course and risks. The goal of this study is to compare the allelic architecture of early onset IBD with adult onset in population of European descent. Methods We performed a fine mapping association study of early onset IBD using high-density Immunochip genotyping on 1008 pediatric-onset IBD cases (801 Crohn’s disease; 121 ulcerative colitis and 86 IBD undetermined) and 1633 healthy controls. Of the 158 SNP genotypes obtained (out of the 163 identified in adult onset), this study replicated 4% (5 SNPs out of 136) of the SNPs identified in the Crohn’s disease (CD) cases and 0.8% (1 SNP out of 128) in the ulcerative colitis (UC) cases. Replicated SNPs implicated the well known NOD2 and IL23R. The point estimate for the odds ratio (ORs) for NOD2 was above and outside the confidence intervals reported in adult onset. A polygenic liability score weakly predicted the age of onset for a larger collection of CD cases (p< 0.03, R2= 0.007), but not for the smaller number of UC cases. Conclusions The allelic architecture of common susceptibility variants for early onset IBD is similar to that of adult onset. This immunochip genotyping study failed to identify additional common variants that may explain the distinct phenotype that characterize early onset IBD. A comprehensive dissection of genetic loci is necessary to further characterize the genetic architecture of early onset IBD.

It is important to determine the effects of immunomodulators on the ability of children to remain on infliximab therapy for Crohn's disease (durability of therapy), given the potential benefits and risks of concomitant therapy-especially with thiopurines in male patients. We investigated how immunomodulatory treatment affects the durability of infliximab therapy.We collected data from the Pediatric Inflammatory Bowel Disease Collaborative Research Group Registry, from January 2002 through August 2014, on 502 children with Crohn's disease who participated in a prospective multicenter study. Data were collected from patients who received at least a 3-dose induction regimen of infliximab, and their concomitant use of immunomodulators: no thiopurine or methotrexate treatment, treatment for 6 months or less during infliximab therapy, or treatment for more than 6 months during infliximab therapy.The probabilities (± standard error) that children remained on infliximab therapy for 1 year, 3 years, and 5 years after the treatment began were 0.84 ± 0.02, 0.69 ± 0.03, and 0.60 ± 0.03, respectively. Age, sex, and disease extent or location did not affect the durability of infliximab therapy. Greater length of concomitant use of immunomodulators was associated with increased time of infliximab therapy. The probability that patients with more than 6 months of immunomodulator use remained on infliximab therapy for 5 years was 0.70 ± 0.04, compared with 0.48 ± 0.08 for patients who did not receive immunomodulators and 0.55 ± 0.06 for patients who received immunomodulators for 6 months or less (P.001). In boys who received immunomodulators for 6 months or more after starting infliximab, the overall durability of infliximab therapy was greater among patients receiving methotrexate than thiopurine (P.01); the probabilities that they remained on infliximab therapy for 5 years were 0.97 ± 0.03 vs 0.58 ± 0.08, respectively.In children with Crohn's disease, concomitant treatment with an immunomodulator for more than 6 months after starting infliximab therapy increases the chances that patients will remain on infliximab. In boys, methotrexate appears to increase the durability of infliximab therapy compared with thiopurine.

BACKGROUND Methotrexate (MTX) use as an alternative to thiopurines in the treatment of Crohn's disease (CD) in children is increasing. This study was undertaken to assess safety and efficacy of MTX in children with CD. METHODS Patients treated with MTX with a minimum of 1-year follow-up were identified in the Pediatric IBD Collaborative Research Group Registry, a prospective inception cohort study started in 2002. The clinical efficacy and safety of MTX were analyzed retrospectively. RESULTS Two hundred ninety patients treated with MTX were identified. One hundred seventy-two patients received at least 3 months of MTX without thiopurine or biologicals and had ≥1 year of follow-up. Eighty-one of 172 patients (47%) received MTX as first immunomodulator (IMM), of which 22 (27%) achieved ≥12 months of sustained clinical remission without surgery, thiopurine, biologicals, or corticosteroids. Those receiving MTX as second IMM achieved similar remission rate (35%, P = not significant). Fourteen percent received MTX as first IMM in 2002 and 60% in 2010 (P = 0.005). Disease location did not affect outcomes. MTX doses were equivalent in both groups. Fifteen percent of patients developed an alanine aminotransferase >60 international units/liter and 12% developed a white blood cell

Inflammatory bowel disease-associated liver diseases (IBD-LDs) include autoimmune hepatitis (AIH), primary sclerosing cholangitis (PSC), and an overlap syndrome. Prospective unbiased multicenter data regarding the frequency of IBD-LD in patients with pediatric inflammatory bowel disease (IBD) are lacking. We examined early alanine aminotransferase (ALT) and γ-glutamyl transpeptidase (GGT) elevations in children diagnosed as having IBD and assessed the likelihood of IBD-LD.Data collected from the prospective observational Pediatric Inflammatory Bowel Disease Collaborative Research Group Registry enrolling children of age16 years within 30 days of diagnosis. AIH, PSC, and overlap syndrome were diagnosed using local institutional criteria.A total of 1569 subjects had liver enzymes available. Of the total, 757 had both ALT and GGT, 800 had ALT only (no GGT), and 12 had GGT only (no ALT). Overall, 29 of 1569 patients (1.8%) had IBD-LD. IBD-LD was diagnosed in 1 of 661 (0.15%) of patients with both ALT and GGT ≤ 50 IU/L compared with 21 of 42 (50%) of patients with both ALT and GGT 50 (odds ratio 660, P 0.0001). Of the 29 patients with IBD-LD, 21 had PSC, 2 had AIH, and 6 had overlap syndrome. IBD-LD was more common in patients with ulcerative colitis and IBD-unclassified (indeterminate colitis) than in those with Crohn disease (4% vs 0.8%, respectively, P 0.001).Elevation of both ALT and GGT within 90 days after the diagnosis of IBD is associated with a markedly increased likelihood of IBD-LD. Both ALT and GGT levels should be measured in all of the pediatric patients newly diagnosed as having IBD.

Despite a paucity of published supporting data, 5-aminosalicylate (5-ASA) use in pediatric ulcerative colitis (UC) is common. The present study describes the use and outcome of a large multicenter inception cohort of children with UC treated with 5-ASA.Data were obtained from the Pediatric Inflammatory Bowel Disease Collaborative Research Group Registry, a prospective North American observational study of children newly diagnosed as having inflammatory bowel disease ages 16 years or younger. Patient data are recorded at diagnosis, 30 days, and then quarterly. Patients are managed by physician dictate, not protocol. Disease activity is classified by physician global assessment. The primary outcome examined was corticosteroid (CS) free, inactive UC at 1 year following initiation of 5-ASA within 30 days of diagnosis (with or without concomitant CS use) without the need for rescue therapy (immunomodulators, biologics, or colectomy).Study subjects included 213 patients newly diagnosed as having UC who received oral 5-ASA compounds (115 of whom also received CS) during the first 30 days after diagnosis, and no other oral therapies for the treatment of UC. Of these 213 patients, 86 (40%) were CS free and physician global assessment inactive at 1 year without rescue. Outcome was not associated with disease severity at diagnosis, demographic or laboratory factors examined, or initial dose of 5-ASA used.Forty percent of children taking 5-ASA as primary maintenance therapy at diagnosis are in CS-free remission after 1 year of treatment. Further pediatric studies will be needed to address whether increased adherence and/or higher dosing schedules will improve outcomes.

Background: The Pediatric Crohn’s Disease Activity Index (PCDAI) has become the standard outcome measure in pediatric Crohn’s disease (CD) clinical research. Other versions have been proposed but without systematic evaluation. The aim was to assess validity and responsiveness of the abbreviated PCDAI (abbrPCDAI), short PCDAI (shPCDAI), and modified PCDAI (modPCDAI) as measures of disease activity and to compare these with a mathematically weighted version developed here (wPCDAI). Methods: The raw data from four prospectively collected datasets were used, totaling 437 children with CD (including two clinical trials). Discriminant validity utilized physician global assessment of disease activity (PGA), and construct validity the correlation with PGA and laboratory results. Feasibility and face validity were ascertained by a survey of 33 experts in pediatric CD. Results: The wPCDAI had better performance than the PCDAI in construct validity and responsiveness and it discriminated better between the disease activity categories (area under the receiver operator characteristic [ROC] 0.97; 95% confidence interval [CI]: 0.95–0.99). In comparison to the original PCDAI, the noninvasive versions (abbrPCDAI and shPCDAI) had lower face, construct, and discriminant validity but were judged to be significantly more feasible. The modPCDAI performed well in the construct validation but was consistently inferior in all other parameters. Cutoffs that correspond to remission, response, and gradations of disease activity were determined for each index. Conclusions: The newly weighted wPCDAI performed better than the original PCDAI and is more feasible. The noninvasive versions (shPCDAI and abbrPCDAI) are inferior to the full PCDAI, but when needed in retrospective studies either may be equally used.

Although it is known that extraintestinal manifestations (EIMs) commonly occur in pediatric inflammatory bowel disease (IBD), little research has examined rates of EIMs and their relation to other disease-related factors in this population. The purpose of this study was to determine the rates of EIMs in pediatric IBD and examine correlations with age, sex, diagnosis, disease severity, and distribution.Data were prospectively collected as part of the Pediatric IBD Collaborative Research Group Registry, an observational database enrolling newly diagnosed IBD patients16 years old since 2002. Rates of EIM (occurring anytime during the period of enrollment) and the aforementioned variables (at baseline) were examined. Patients with indeterminate colitis were excluded from the analysis given the relatively small number of patients.One thousand nine patients were enrolled (mean age 11.6 +/- 3.1 years, 57.5% boys, mean follow-up 26.2 +/- 18.2 months). Two hundred eighty-five (28.2%) patients experienced 1 or more EIMs. Eighty-seven percent of EIM occurred within the first year. Increased disease severity at baseline (mild vs moderate/severe) was associated with the occurrence of any EIM (P0.001), arthralgia (P = 0.024), aphthous stomatitis (P = 0.001), and erythema nodosum (P = 0.009) for both Crohn disease (CD) and ulcerative colitis (UC) during the period of follow-up. Statistically significant differences in the rates of EIMs between CD and UC were seen for aphthous stomatitis, erythema nodosum, and sclerosing cholangitis.EIMs as defined in this study occur in approximately one quarter of pediatric patients with IBD. Disease type and disease severity were commonly associated with the occurrence of EIMs.

Infliximab is effective in treating moderate/severe ulcerative colitis (UC) in adults. The aim of this study was to determine the outcome after treatment with infliximab in pediatric UC.We performed a multicenter cohort study of 332 pediatric patients with UC enrolled in the Pediatric Inflammatory Bowel Disease Collaborative Research Group Registry. Childrenor=16 years of age and newly diagnosed with UC are enrolled in the registry. Disease and medication information are collected prospectively from the treating physician at diagnosis, 30 days, and quarterly thereafter. No interventions were specified, per protocol.Of 332 patients, 52 (16%) received infliximab (23%3 months from diagnosis, 38% 3-12 months, 38%12 months). Mean age at infliximab initiation was 13.3+/-2.6 (range 6-17) years; 87% of patients had pancolitis. Median follow-up was 30 months. Continuous maintenance (CM) therapy was given in 65%, episodic in 21%, episodic converted to CM in 6%, and insufficient data in 8% of patients. Sixty-three percent of patients were corticosteroid refractory, and 35% were corticosteroid dependent. Concomitant medications at first infliximab infusion included corticosteroids (87%), thiopurines (63%), and 5-aminosalicylates (51%). Corticosteroid-free inactive disease by physician global assessment was noted in 12/44 (27%), 15/39 (38%), and 6/28 (21%) patients at 6, 12, and 24 months, respectively. Kaplan-Meier analysis showed that the likelihood of remaining colectomy free after treatment with infliximab was 75% at 6 months, 72% at 12 months, and 61% at 2 years.In this cohort of children with UC receiving infliximab, corticosteroid-free inactive disease was observed in 38 and 21% of patients at 12 and 24 months, respectively. By 24 months, 61% of patients had avoided colectomy.

Adalimumab, an anti-tumor necrosis factor immunoglobulin-1 antibody, is increasingly being reported as a potential treatment option for children with moderate-to-severe Crohn's disease (CD). The aim of this study was to characterize common indications, safety, tolerability, and clinical response to adalimumab in pediatric CD in a large, multicenter, patient cohort.Data were obtained using a retrospective, uncontrolled chart review at 12 sites of the Pediatric Inflammatory Bowel Disease Collaborative Research Group. Clinical, laboratory, and demographic data were obtained for CD patients who received at least one dose of adalimumab. Indication for adalimumab, concomitant medications, and clinical outcome at 3, 6, and 12 months for each patient were recorded using physician global assessment (PGA) and Pediatric CD Activity Index scores. Serious adverse events were identified.A total of 115 patients (54% female) received at least one dose of adalimumab. The mean age at the diagnosis of CD was 11.1+/-3.1 years, with the first adalimumab dose administered at 4.7+/-2.8 years after diagnosis. The most common dosing frequency was every other week with induction doses of 160/80 mg in 19%, 80/40 mg in 44%, and 40/40 mg in 15% of patients. Maintenance dosing was 40 mg every other week in 88% of patients. Mean follow-up after initial adalimumab dose was 10+/-8.6 months. Infliximab treatment preceded adalimumab in 95% of patients, with a mean of 12 infliximab infusions (range: 1-44). Infliximab discontinuation was due to loss of response (47%), infusion reaction or infliximab intolerance (45%), or preference for a subcutaneous medication (9%). Concomitant medications at the commencement of adalimumab were corticosteroids (38%), azathioprine/6-mercaptopurine (41%), and methotrexate (23%). Clinical response measured by PGA at 3, 6, and 12 months was 65, 71, and 70%, respectively, with steroid-free remission at 3, 6, and 12 months of 22, 33, and 42%, respectively. There were no malignancies, serious infections, or deaths in the study subjects.Adalimumab was a well-tolerated and effective rescue therapy for moderate-to-severe pediatric CD patients previously treated with infliximab. Adalimumab demonstrated a steroid-sparing effect, and70% of patients achieved rapid response that was sustained through 12 months.

Background: Infliximab therapy has short-term benefits in children with moderate-to-severe Crohn's disease (CD). We assessed the long-term outcome of infliximab maintenance therapy in children with CD. Methods: We performed a multicenter cohort study of 729 pediatric patients with CD enrolled in the Pediatric Inflammatory Bowel Disease Collaborative Research Group Registry. Children younger than 16 years and newly diagnosed with CD were eligible for this study. Disease and medication information were collected prospectively from the treating physician at diagnosis, 30 days, and quarterly thereafter. No interventions were specified, per protocol. Results: In all, 202 of 729 patients received infliximab: 62%, 23%, and 15% within 1, 1–2, and >2 years of diagnosis, respectively. The mean age at infliximab initiation was 12.7 years. A total of 158 infliximab-treated patients received maintenance therapy, 29 episodic (8 converted to maintenance), and 15 had incomplete follow-up. Among 128 patients administered maintenance infliximab and followed for ≥1 year, concomitant medications at infliximab initiation included corticosteroids (52%) and immunomodulators (90%). By 1, 2, and 3 years

Background: We sought to characterize perianal disease and its treatment in pediatric patients newly diagnosed with Crohn's disease. Methods: Data were obtained from the Pediatric Inflammatory Bowel Disease (IBD) Collaborative Group Registry, a prospective, multicenter observational registry recording clinical and laboratory outcomes in children under 16 years of age newly diagnosed with IBD. Patients with Crohn's disease were selected who had data on perianal disease and at least 24 months of follow-up. The records of patients with a Pediatric Crohn's Disease Activity Index perianal subscore greater than 0 were reviewed, and patients with abscesses or fistulas were selected. The therapies used and the course of their perianal disease were then assessed. Results: Of the 276 patients identified, 41 had perianal lesions within 30 days of diagnosis. Thirteen of these had skin tags and fissures only, whereas 28 had fistulas and/or abscesses. The latter lesions resolved by 1 year in 20 patients, and 8 had chronic/recurrent perianal disease persisting for more than 1 year following diagnosis. Patients with fistulizing disease were much more likely to be treated and were treated earlier with antibiotics, infliximab, and immunomodulators than were nonfistulizing patients. Patients who developed chronic perianal disease were more likely to have low body mass indices and required more perianal surgery than did patients whose perianal disease resolved. Conclusions: Approximately 10% of newly diagnosed pediatric patients with Crohn's disease will have perianal fistulas and/or abscesses at the time of diagnosis. Most of these will resolve within a year with medical therapy alone. (Inflamm Bowel Dis 2008)

Risk factors for postoperative infections have not been evaluated in pediatric patients with ulcerative colitis (UC). This review was undertaken to evaluate the effects of immunosuppressive therapy and other preoperative factors on infectious wound complications in children undergoing first stage surgical therapy for UC.A 10-year retrospective review of children under 18 years of age receiving first stage surgical therapy for UC at a major children's hospital was performed. Preoperative clinical and treatment variables were identified and correlated with postoperative wound complications.A total of 51 children were identified: 19 underwent colectomy with ileo-anal-pouch anastomosis and 32 underwent total abdominal colectomy with Hartmann's pouch. A total of 20 infectious complications were identified in 18 patients. Preoperative steroid use was associated with a greater postoperative wound infection rate. Preoperative hemoglobin less than 10 g/dL (P.05) and albumin less than 3 g/dL (P = 0.1) were associated with greater rates of postoperative infection. Preoperative body mass index and other immunosuppressive agents did not influence postoperative infectious morbidity.The majority of pediatric patients who require operative intervention for UC are debilitated from their disease and medication use. Children with normal serum albumin and hemoglobin who are not on steroid therapy have a low risk of postoperative infectious complications.

Objective To evaluate the presentation, therapeutic management, and long-term outcome of children with very early-onset (VEO) (≤5 years of age) inflammatory bowel disease (IBD). Study design Data were obtained from an inception cohort of 1928 children with IBD enrolled in a prospective observational registry at multiple centers in North America. Results One hundred twelve children were ≤5 years of age with no child enrolled at P = .04), and 11- to 16-year-olds (22.3%, P P = .01). Five years postdiagnosis, there was no difference in disease activity among the 3 groups. However, compared with the oldest group, a greater proportion of 1- to 5-year-olds with CD were receiving corticosteroids ( P P P P Conclusions Children with VEO-CD are more likely to have mild disease at diagnosis and present with a colonic phenotype with change to an ileocolonic phenotype noted at 6-10 years of age. Five years after diagnosis, children with VEO-CD and VEO-UC are more likely to have been administered corticosteroids and immunomodulators despite similar disease activity in all age groups. This may suggest development of a more aggressive disease phenotype over time.

Background and Aims: Assessment of health-related quality of life (HRQOL) is of increasing importance in the evaluation of new therapies for inflammatory bowel disease (IBD). Available data concerning HRQOL in pediatric patients are sparse and uniformly cross-sectional. The aim of this study was to describe HRQOL and influential factors in newly diagnosed pediatric patients with Crohn's disease and ulcerative colitis during the first 12 months after diagnosis. Materials and Methods: Participants were drawn from a large, prospectively derived observational IBD registry of pediatric patients studied through 18 U.S. and Canadian centers. Patients who had completed a baseline IMPACT questionnaire and for whom there were 12 months of follow-up data available were included. In addition to description of cohort, factors that were believed to influence HLQOL were assessed during the course of the year from diagnosis. Results: Two hundred eighteen children met inclusion criteria (77% Crohn's disease, 23 % ulcerative colitis, mean age 12.7 ± 1.9 years). Mean total IMPACT score at baseline was 154, 181 at 6 months, and 191 at 1 year (possible range 0-238, with increasing scores representing better quality of life). Repeated measures analysis showed that age and disease severity significantly negatively affected the IMPACT scores during the course of the year. Conclusions: In this large prospective pediatric IBD cohort, significant improvement in HRQOL is noted during the year from diagnosis. Mean IMPACT scores varied significantly depending on the disease severity and also decreased with increasing age.

Background & Aims: The aim of this study was to describe 3-month and 1-year outcomes of children with Crohn's disease (CD) treated with corticosteroids within 30 days of diagnosis, with particular emphasis on the influence of infliximab on these outcomes. We also aimed to determine whether there are clinical or laboratory characteristics associated with corticosteroid therapy outcomes. Methods: Data from 109 children were drawn from a multicenter observational registry that was started in 2002. Clinical characteristics and data on corticosteroid and other therapies were recorded prospectively. Corticosteroid therapy outcomes at 3 months were defined as complete acute response, partial response, or corticosteroid resistance. At 1 year, corticosteroid responsiveness, dependence, and surgical rates were determined. Infliximab's influence on short- and long-term outcomes also was investigated. Results: At 3 months, 65 of 109 (60%) patients had a complete acute response to corticosteroids, 26 (24%) had a partial response, and 18 (17%) were corticosteroid resistant. At 1 year, 61% were corticosteroid responsive, 31% were corticosteroid dependent, and 8% required surgery. Irrespective of the duration of corticosteroid treatment, 16 of 24 of corticosteroid-dependent/resistant patients rapidly discontinued corticosteroids after starting infliximab. No clinical or laboratory characteristics at diagnosis predicted short-term outcome. Growth impairment at diagnosis increased risk for corticosteroid dependence or surgery at 1 year. Conclusions: At 3 months, 84% of children had a complete or partial response to corticosteroids. However, despite concomitant immunomodulators, at 1 year 31% were corticosteroid dependent and 8% required surgery. Infliximab improves outcomes of corticosteroid-dependent/resistant patients because the duration of corticosteroid use can be controlled by initiating treatment with infliximab.

Background & Aims We examined the incidence of Crohn's disease (CD)-related surgery in a multi-center, inception cohort of pediatric patients with CD. We also examined the effect of starting immunomodulator therapy within 30 days of diagnosis. Methods Data from 854 children with CD from the Pediatric Inflammatory Bowel Disease Collaborative Research Group who were diagnosed with CD between 2002 and 2008 were analyzed. Results Overall, 76 (9%) underwent a first CD-related surgery, 57 (7%) underwent a first bowel surgery (bowel resection, ostomy, strictureplasty, or appendectomy), and 19 (2%) underwent a first non-bowel surgery (abscess drainage or fistulotomy). The cumulative risks for bowel surgery, non-bowel surgery, and all CD-related surgeries were 3.4%, 1.4%, and 4.8%, respectively, at 1 year after diagnosis and 13.8%, 4.5%, and 17.7%, respectively, at 5 years after diagnosis. Older age at diagnosis, greater disease severity, and stricturing or penetrating disease increased the risk of bowel surgery. Disease between the transverse colon and rectum decreased the risk. Initiation of immunomodulator therapy within 30 days of diagnosis, sex, race, and family history of inflammatory bowel disease did not influence the risk of bowel surgery. Conclusions In an analysis of pediatric patients with CD, the 5-year cumulative risk of bowel surgery was lower than that reported in recent studies of adult and pediatric patients but similar to that of a recent retrospective pediatric study. Initiation of immunomodulator therapy at diagnosis did not alter the risk of surgery within 5 years of diagnosis.