A164 IDENTIFYING THE MOST IMPORTANT PREDICTORS TO CORRELATE SERUM METABOLITES WITH MRE CHANGES IN PATIENTS WITH PEDIATRIC CROHN DISEASE

Background

Endoscopy has been the gold standard for assessing activity in Pediatric Crohn disease (pCD); however, it is limited by its invasiveness and partial assessment of small intestine and transmural inflammation. To that end, the Pediatric Inflammatory Crohn's MRE Index (PICMI) is a valid, reliable, non-invasive, and responsive index that includes transmural inflammation when assessing disease activity.

The pathogenesis of pCD remains poorly understood, but evidence suggests that endogenous metabolites produced in the intestinal tract might mediate pathogenesis. Despite the important applicability of metabolomics in increasing the understanding of pCD, there has been limited research on this topic.

Purpose

Serum metabolomic profiles are linked to disease activity in pediatric Crohn disease.

Method

ImageKids is a multicenter, prospective, observational cohort study, designed to develop PICMI for pCD. The study was conducted over 18 months with paired serum specimens collected at study initiation and completion for 56 pCD patients. Due to the long time between the visits and the fact that during the study variables that highly affect serum metabolites were not controlled, we considered each patient visit as an individual measure point. Metabolites were identified using a quantitative metabolomics approach through The Metabolomics Innovation Centre (TMIC; University of Alberta). Disease activity was determined by the cutoff values in the total PICMI score of each patient.

The most relevant serum metabolites were identified by medium-level and high-level variable selection analysis. Pearson correlation and hypothesis testing were used to select important metabolites. Decision trees, regularization techniques, and support vector machines were used to assess explicit importance of metabolites in disease activity.

Result(s)

This work provides a strategy to reduce a dimensional dataset from a metabolomic experiment. By medium-level selection analysis we were able to identify 117 statistical important metabolites for disease activity. The high-level selection analysis allowed to indicate the importance of the top 10 metabolites trough disease activity (defined by PICMI index). Results, also show that the evaluation of importance of metabolites through multivariate statistical models is dependent of the intrinsic variable selection model.

Figure 1 reveals that Tryptophan ranked highest in the feature importance scoring. Histidine, Methylhistidine, Citric acid, Isoleucine, and Decanoylcarnitine also correlated well with disease severity.

Image

Conclusion(s)

This work uses a unique approach of multivariate statistical analyses, to identify metabolites associated with pCD disease activity. Tryptophan has been previously identified as significantly altered in the blood of IBD patients compared to controls. Histidine is known to be involved in the mediation of oxidative stress, potentially influencing intestinal inflammation. These metabolites could serve as biomarkers and help define pCD pathogenesis.

Disclosure of Interest

None Declared

A198 THE LONG-TERM IMPACT OF ENVIRONMENTAL EXPOSURES ON HOST HEALTH AND THE RISK FACTORS OF CROHN'S DISEASE

Background

Several environmental factors are associated with Crohn’s disease (CD) in large case-control studies; however, it is not clear how these factors maybe be influenced by age of exposure and if they are related to alterations in pre-disease biological markers of CD risk.

Purpose

To investigate the association between environmental factors in different age groups with future risk of CD onset and assess their relation to other pre-disease biomarkers.

Method

We used an environmental risk assessment questionnaire (ERA) to collect information from healthy first-degree relatives(FDR) of CD enrolled in the CCC-GEM project. ERA was a multi-item questionnaire querying 69 questions under 7 section headings: background, cultural/ethnic, smoking history, medical history, family history, environmental history and pet history. For the environmental and pet sections, current and historical (<1, 2-4, 5-15 years old) data was captured at the time of recruitment. We used Cox proportional hazard models to identify exposures associated with future CD onset. Next, we used regression models to identify the relationship of exposures with biological factors associated with CD risk previously identified by our group i.e.: i) intestinal permeability using urinary fractional excretion of lactulose to mannitol ratio (LMR) with LMR≥0.025 defined as abnormal; ii) subclinical inflammation using fecal calprotectin (FCP) with FCP≥100µg/g; and iii) fecal microbiome composition and diversity using 16S rDNA sequencing. Two-sided p<0.05 (or false discovery rate corrected p<0.05) were considered significant.

Result(s)

A total of 4289 FDRs were recruited, 47% were male, median recruitment age was 17.0 years[6-35]. After a median follow-up of 5.6-years (IQR=3.42-8.67), 86 FDRs developed CD. Living with a dog between age 5-15 (Hazard Ratio (HR)=0.61; 95% confidence interval (CI)=0.39-0.95), and a large family size (>3) in the first year of life (HR=0.41; 95% CI=0.22-0.89) were protective against CD onset. Conversely, having a bird at time of survey (HR=2.84; CI=1.37-5.90), and having a sibling with CD (HR=2.07; 95% CI=1.18-3.63) were risk factors for CD onset. We found that owning a dog between age of 5-15 (Odd Ratio(OR)=0.77, 95% CI=0.65-0.90) was significantly associated with LMR, nine taxa bacterial and higher chao1 diversity index. Having a bird at time of survey was significantly associated with FCP (OR=2.04, 95% CI=1.33-3.11). There was no association between large family size and having a CD sibling with gut microbiome, FCP or LMR.

Conclusion(s)

The study identified four environmental factors associated with future development of CD. Among them, exposure to dogs during early life was protective against CD onset and might be explained by its association with normal gut permeability and microbiome. We also identified that having a bird at recruitment increased risk of CD onset which might be mediated by an increase in subclinical inflammation.

Submitted on behalf of the CCC-GEM consortium

Disclosure of Interest

None Declared

A183 VARIATION IN HEALTH SERVICES UTILIZATION AND RISK OF SURGERY ACROSS CHILDREN WITH INFLAMMATORY BOWEL DISEASE: A MULTIPROVINCE COHORT STUDY

Background

Marked variation in access to care and health services utilization is a marker of variation in quality of care. With the rising incidence of pediatric inflammatory bowel disease (IBD), we must understand variation in access to and outcomes of care to improve quality.

Purpose

Describe variation in care for pediatric IBD treated in 4 Canadian provinces.

Method

Incident cases of IBD diagnosed in children <16y were identified from health administrative data in Alberta (AB), Manitoba, Nova Scotia, and Ontario (ON) using validated algorithms. Children were assigned to one of 8 centres of care using a hierarchical assessment of health services use within 6 months of diagnosis. Children treated by adult gastroenterologists or community-based pediatric gastroenterologists were excluded due to small sample size. Outcomes included IBD-related hospitalizations, emergency department (ED) visits (AB/ON only), and IBD-related abdominal surgery. Hospitalizations and ED visits were counted cumulatively from 6-60 months after diagnosis. The risk of first surgery was defined during the same 6-60 month period. Mixed-effects meta-analysis was used to pool results across centres. Heterogeneity among centres was quantified using I² (variation in pooled event rates between centres) and τ (standard deviation of the true event rates). R² quantified the residual heterogeneity in outcomes not attributable to among-province variation.

Result(s)

We identified 3777 incident cases of pediatric IBD, 2936 (78%) of which were treated at 8 pediatric centres. The number of hospitalizations was 0.67 (95% CI 0.56-0.79) per person with high between-centre heterogeneity (I² 84%, τ 0.1556). Provincial differences accounted for 93% of heterogeneity across centres (residual heterogeneity: I² 29%, τ 0.0412). Hospitalizations were less frequent in AB than other provinces (0.43 vs. 0.72-0.78). Children averaged 1.94 IBD-related ED visits, with significant heterogeneity (I² 99%, τ 1.33) with 99.7% of heterogeneity attributable to among-province differences (residual heterogeneity: I² 32%; τ 0.074). Mean ED visits were 1.1 visits in ON (I² 39%) and 3.7 in AB (I² 0%). Intestinal resection was required by 12% (95% CI 0.08-0.15) of Crohn’s patients with high among-centre heterogeneity (I² 81%, τ 0.042), and low (19%) heterogeneity due to provincial differences (residual heterogeneity: I² 76%; τ 0.039). Colectomy was required by 12% (95% CI 10-14) of children with ulcerative colitis (UC) with no between-centre heterogeneity (I² 0%, τ 0).

Conclusion(s)

There is a high degree of between-province (but not between-centre, within province) variability in health services utilization among children with IBD. There was significant between-centre variability in surgery rates for Crohn’s, but not colectomy for UC. Differences in patient characteristics or provincial health systems may be more important predictors of variation in care. Surgery for Crohn’s disease may be a target for inter-centre quality improvement efforts.

Please acknowledge all funding agencies by checking the applicable boxes below

CCC

Disclosure of Interest

None Declared

A182 PREDICTING HIGH DIRECT HEALTHCARE COSTS IN PEDIATRIC PATIENTS WITH INFLAMMATORY BOWEL DISEASE IN THE FIRST YEAR FOLLOWING DIAGNOSIS

Background

The incidence of inflammatory bowel disease (IBD) continues to rise rapidly among Canadian children. The care of children results in higher direct healthcare costs than adults with IBD. It is imperative that we identify individuals who will become the highest-cost users of the health system in order to intervene early and decrease the individual- and system-level burden of IBD.

Purpose

To develop a predictive-model for high-cost health system users and (2) identify factors associated with high-cost healthcare use.

Method

Incident cases of IBD diagnosed ≤17y residing in Ontario and enrolled in the Canadian Children IBD Network (CIDsCaNN) between Dec 31 2013 and Jan 31 2019 were linked deterministically using health card number to health administrative data. Using a validated algorithm, direct healthcare costs accumulated between the 31^st and 365^th day after diagnosis were calculated using data from CIDsCaNN (medications) and health administrative data (health system encounters, including surgery). A predictive model was created to determine high-cost (≤25^th percentile) and medium-cost (26^th to 75^th) users, compared to low-cost users (>75th) using ordinal logistic regression. Potential predictive variables were determined a priori based on clinical significance and magnitude of univariable association, based on sample size-informed degrees of freedom. Variables from CIDsCaNN data included: IBD type, age at diagnosis, sex, first line of therapy (steroids, aminosalicylates, exclusive enteral nutrition; yes or no, not mutually exclusive), disease activity (severe vs. moderate vs. none/mild based on PUCAI [UC] or wPCDAI [Crohn’s]). Predictive variables from the health administrative data included: rural/urban residence, hospitalization at diagnosis, intestinal resection or colectomy within 3 months of diagnosis, emergency department visit ±1 month of diagnosis, and a mental health encounter within the first year following diagnosis. Anti-TNF treatment was excluded from models due to the strong correlation with the outcome (direct costs). Overall model fit was estimated with a c-statistic.

Result(s)

Among the 487 (57% Crohn’s) children included in the study, the mean (sd) direct costs accumulated between the 31^st and 365^th days following IBD diagnosis was $14,451 (14,665). The mean cost among high-cost users was $33,533 (16,530); medium-cost users, $11,038 (5322); low-cost users, $2530 (831). The predictive model identified high-cost users of the health system with acceptable model fit (c-statistic 0.69). The relative contribution of individual variables, as measured by odds ratio (OR), is reported in the Table.

Image

Conclusion(s)

The direct healthcare costs of pediatric IBD are substantial. Children with IBD who become high-cost users of the health system were identifiable using characteristics at diagnosis (e.g., need for mental health care, emergency visits, older age). Further research should assess whether interventions in patients at-risk for becoming high-cost users may help to reduce costs.

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Other

Please indicate your source of funding;

Ontario Academic Health Sciences Centres Alternate Funding Plan Innovation Fund

Disclosure of Interest

E. Kuenzig: None Declared, R. Duchen: None Declared, T. Walters Grant / Research support from: Janssen, Abbvie, Psfizer, Ferring, Amgen, Consultant of: Janssen, Abbvie, Psfizer, Ferring, Amgen, D. Mack: None Declared, A. Griffiths Grant / Research support from: Abbvie, Consultant of: Abbvie, Amgen, BristolMyersSquibb, Janssen, Lilly, Takeda, Speakers bureau of: Abbvie, Janssen, Takeda, C. Bernstein Grant / Research support from: Research grants from Abbvie Canada, Amgen Canada, Pfizer Canada, and Sandoz Canada and contract grants from Janssen, Abbvie and Pfizer, Consultant of: Abbvie Canada, Amgen Canada, Bristol Myers Squibb Canada, JAMP Pharmaceuticals, Janssen Canada, Pfizer Canada, Sandoz Canada, Takeda, Speakers bureau of: Abbvie Canada, Janssen Canada, Pfizer Canada and Takeda Canada, G. Kaplan Grant / Research support from: Ferring, Consultant of: AbbVie, Janssen, Pfizer, Amgen, Sandoz, Pendophram, and Takeda, Speakers bureau of: AbbVie, Janssen, Pfizer, Amgen, Sandoz, Pendophram, and Takeda, A. Otley Grant / Research support from: Research support: AbbVie Global. Research site: AbbVie, Pfizer, Eli-Lily, Janssen, Consultant of: AbbVie Canada, W. Yu: None Declared, X. Wang: None Declared, J. Guan: None Declared, S. Fung: None Declared, E. Benchimol Consultant of: McKesson Canada, Dairy Farmers of Ontario (unrelated to medications used to treat inflammatory bowel disease)

A189 EMERGENCY DEPARTMENT UTILIZATION AND RISK OF INTESTINAL RESECTION IS LOWER AMONG CHILDREN DIAGNOSED WITH INFLAMMATORY BOWEL DISEASE BEFORE 10 YEARS OF AGE: A MULTIPROVINCE POPULATION-BASED COHORT STUDY

Background

In Canada, the incidence of inflammatory bowel disease (IBD) is increasing faster among those <10 years (y) of age than in any other age group. Understanding the health services burden of IBD in this population is important for health system planning.

Purpose

To compare healthcare utilization and risk of surgery among children diagnosed with IBD across age groups defined by the Paris Classification (A1a: <10y; A1b: 10 to <16y) across 5 Canadian provinces.

Method

Children diagnosed with IBD <16 years of age were identified from health administrative data using validated algorithms in Alberta, Manitoba, Nova Scotia, Ontario, and Québec. Negative binomial regression models were used to compare (1) the pre-diagnosis frequency of health services utilization (outpatient, emergency department (ED), and hospitalization) using diagnostic codes suggestive of future IBD and (2) the annual post-diagnosis frequency of IBD-specific and IBD-related (signs, symptoms, and extra-intestinal manifestations of IBD) visits among children diagnosed <10y (A1a) and 10 to <16y (A1b). Cox proportional hazard models compared the risk of surgery (identified with validated procedure codes) across age groups. All regression models were adjusted for sex, rural/urban residence, and mean neighbourhood income quintile. Province-specific event counts (all ages combined) and models (comparing age groups; reference: A1b [10 to <16y]) were pooled using random-effects meta-analysis.

Result(s)

Among 5124 children with IBD (1165 [23%] were <10y at diagnosis), the mean number of pre-diagnosis healthcare encounters was 1.0 (95% CI 0.38 to 1.68, I²=99.6%). The mean annual post-diagnosis number of IBD-specific outpatient visits was 3.2 (95% CI 1.9-4.4, I²=99.6%); hospitalizations, 0.19 (95% CI 0.17-0.21, I²=74%); ED visits, 0.17 (95% CI 0.19-0.39, I²=99%). The mean annual post-diagnosis number of IBD-related outpatient visits was 3.9 (95% CI 2.3-5.5, I²=99.7%); hospitalizations, 0.21 (95% CI 0.19-0.23, I²=79%); ED visits, 0.29 (95% CI 0.19-0.39, I²=97%). Intestinal resection or colectomy within 5y of diagnosis occurred in 13% (95%CI 8-22, I²=93%) with Crohn’s disease (CD) and 16% (95% CI 14-18, I²=40%) with ulcerative colitis. IBD-specific ED visits (RR 0.70, 95% CI 0.50-0.97, I²=80) and the risk of intestinal resection in CD (HR 0.49, 95% CI 0.26-0.92, I²=40%) were significantly lower among children diagnosed <10y. There were no age-related differences in pre-diagnosis health services utilization or other post-diagnosis outcomes, including frequency of outpatient visits to a gastroenterologist.

Conclusion(s)

Health services utilization was generally similar for children diagnosed with IBD at <10y and between 10 and <16y, except for lower rates of IBD-specific ED visits and intestinal resection in children with CD. Further exploration of between-province differences, represented by the high statistical heterogeneity (I²) in the meta-analyses, is needed to understand sources of variation in care.

Please acknowledge all funding agencies by checking the applicable boxes below

CCC

Disclosure of Interest

E. Kuenzig: None Declared, H. Singh Consultant of: Amgen Canada, Bristol-Myers Squibb Canada, Sandoz Canada, Roche Canada, Takeda Canada and Guardant Health, A. Bitton: None Declared, G. Kaplan Grant / Research support from: Ferring, Consultant of: AbbVie, Janssen, Pfizer, Amgen, Sandoz, Pendophram, and Takeda, Speakers bureau of: AbbVie, Janssen, Pfizer, Amgen, Sandoz, Pendophram, and Takeda, M. Carroll: None Declared, A. Otley Grant / Research support from: Research support: AbbVie Global. Research site: AbbVie, Pfizer, Eli-Lily, Janssen, Consultant of: AbbVie Canada, T. Stukel: None Declared, S. Spruin: None Declared, A. Griffiths Grant / Research support from: Abbvie, Consultant of: Abbvie, Amgen, BristolMyersSquibb, Janssen, Lilly, Takeda, Speakers bureau of: Abbvie, Janssen, Takeda, D. Mack: None Declared, K. Jacobson Grant / Research support from: Abbvie Canada and Janssen Canada, Consultant of: Abbvie Canada, Janssen Canada, Merck Canada and Mylan Pharmaceuticals, Speakers bureau of: Abbvie Canada and Janssen Canada, G. Nguyen: None Declared, L. Targownik Grant / Research support from: Janssen Canada, Consultant of: AbbVie Canada, Sandoz Canada, Takeda Canada, Merck Canada, Pfizer Canada, Janssen Canada, and Roche Canada, W. El-Matary Consultant of: Abbvie and MERCK, Speakers bureau of: Abbvie and MERCK, E. Benchimol Consultant of: McKesson Canada, Dairy Farmers of Ontario (unrelated to medications used to treat inflammatory bowel disease)

A218 ASSOCIATIONS BETWEEN ADHERENCE TO LITERATURE-DERIVED DIETARY INDICES AND PRE-DISEASE BIOMARKERS: IMPLICATIONS FOR CROHN’S DISEASE PREVENTION

Background

The incidence of Crohn’s disease (CD) is increasing globally, indicating a significant environmental influence such as diet. A plethora of dietary adherence (DA) patterns exist in the literature: the Mediterranean Diet (MD), Empirical Dietary Inflammatory Pattern (EDIP), Specific Carbohydrate Diet (SCD), and low Fermentable Oligosaccharide, Disaccharide, Monosaccharide, or Polyol diet (FODMAP) are all potential candidates to maintain a reduced level of inflammation, improving gastrointestinal function. Contrary, the Westernized diet (WD) is generally reported as a diet promoting inflammation in humans.

Purpose

To determine if DA to literature-derived dietary indices in a cohort of first-degree relatives (FDRs) of CD patients can modulate pre-disease biomarkers.

Method

We used food frequency questionnaire (FFQ) data from 2,696 healthy FDR subjects of the Crohn’s Colitis Canada- Genes, Environment, Microbial (CCC-GEM) project. We rederived each of the following scores using our FFQ data, utilizing originally described methods for the MD, EDIP, SCD, low FODMAP, and WD to obtain DA. Each diet was correlated pairwise via Kendall’s Tau.

We fit multivariable regression models to identify the association of DA (top quintile vs remaining) and: i) intestinal permeability using urinary fractional excretion of lactulose to mannitol ratio (LMR), LMR≥0.03 defined abnormal; ii) subclinical inflammation using fecal calprotectin (FCP) measured with BÜHLMANN fCAL® ELISA, FCP≥250µg/g defined inflammation; and iii) fecal microbiome richness and composition using 16S rRNA sequencing. Two-sided p<0.05 for primary and q<0.05 for secondary analysis defined significance.

Result(s)

There were positive correlations between the MD, SCD, and low FODMAP, these diets negatively correlated with the WD. The EDIP negatively correlated with the SCD and low FODMAP, did not correlate with the MD, and positively correlated with the WD. No diet was associated with abnormal LMR or FCP. Only the SCD was associated with increased microbial richness (q=0.03). All diets were associated with microbial genera: the MD (n=18 taxa, (2.0^-7<q-values< 0.04), EDIP (n=9, [2.8^-4-0.05]), SCD (n=13, [3.7^-11-0.05]), low FODMAP (n=14, [1.3^-7-0.05]), and WD (n=1, [0.03]).

Conclusion(s)

This study shows that literature-derived dietary indices correlate generally with each other, yet none were not associated with abnormal LMR or FCP. However, we found that diet can impact microbiome richness and composition. Thus, it is tempting to speculate that diet is a possible intervention capable of maintain microbiome homeostasis to reduce future risk of CD.

Submitted on behalf of the CCC-GEM consortium.

Funding

Crohn’s and Colitis Canada Genetics Environment Microbial (CCC-GEM) III

The Leona M. and Harry B. Helmsley Charitable Trust

Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Disease

Disclosure of Interest

None Declared

A238 BILE ACID COMPOSITION AND DIETARY FAT: IMPLICATIONS FOR CROHN’S DISEASE IN A COHORT OF HEALTHY FIRST-DEGREE RELATIVES

Background

Crohn’s disease (CD) is a chronic relapsing inflammatory disease of the gastrointestinal tract. The etiology of CD may arise from complex interactions including host genetics, diet, and the intestinal microbiome. Increased consumption of saturated fats, characteristic of the Western diet, is a known risk factor for CD. Dietary fat (DF) is absorbed by the host through the release of primary bile acids (PBAs) and bio-transformed by the microbiome into secondary bile acids (SBAs). Altogether, bile acids (BAs) can act as signaling molecules involved in host immune regulation and potentially in CD onset.

Purpose

To investigate the relationship between CD risk, BAs, and DF, and evaluate the predictive performance of CD onset of these factors by developing machine learning models.

Method

We used samples healthy first-degree relatives (FDRs) recruited as part of the Crohn’s Colitis Canada- Genes, Environment, Microbial (GEM) project. Those who developed CD (n=87) were matched 1:4 by age, sex, follow-up time, and geographic location with control FDRs remaining healthy (n=347).

Serum, urine, and stool BA were measured using ultrahigh Performance Liquid Chromatography-Tandem Mass Spectroscopy. DF types were derived from food frequency questionnaire data. We used conditional logistic regressions to identify associations between CD onset, BAs (n=93), and DFs (n=9). We further explored the relationships of significant CD-related BAs and DF via Generalized Estimation Equations. Finally, we used a tree-based machine-learning algorithm (XGBoost) with 5-fold cross-validation to assess the prediction performance of CD onset using BA from all sources as well as DF. Two-sided p<0.05 was considered significant.

Result(s)

In total, 10 of 93 BAs, and two of nine DFs were significantly associated with increased odds of CD onset (p<0.05). Additionally, five BAs were significantly associated with DF (p<0.05). Serum-derived BAs had the best predictive performance for CD, with a mean AUC of 0.70 [95% CI: 0.63;0.76], followed by stool derived BAs with a mean AUC= 0.65 [0.55;0.75], and followed by urine derived Bas with a mean AUC= 0.57 [0.48;0.66]. Lastly DF was not a predictive marker of CD onset with a mean AUC= 0.50 [0.41;0.60].

Conclusion(s)

This study suggests that BAs are associated with the pathogenesis of CD and the effects may be influenced by DF. Serum-derived BAs may be able to better predict the risk of CD than other stool or urine derived BA, while DF is not directly implicated in CD risk.

Submitted on behalf of the CCC-GEM consortium.

Funding

Crohn’s and Colitis Canada Genetics Environment Microbial (CCC-GEM) III

The Leona M. and Harry B. Helmsley Charitable Trust

Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Diseases

The International Organization for the Study of Inflammatory Bowel Diseases (IOIBD)

Jingcheng Shao is the recipient of a Data Science Institute Summer Undergraduate Data Science award

Disclosure of Interest

None Declared

The Phenotypic Spectrum of New-onset IBD in Canadian Children of South Asian Ethnicity: A Prospective Multi-Centre Comparative Study

BACKGROUND

Canadian-born children of South Asian [SA] ethnicity develop inflammatory bowel disease [IBD] at similar rates to those among Caucasian children. We evaluated the variation in phenotypic spectrum of IBD in SA and Caucasian children in a national paediatric inception cohort of new-onset IBD.

METHODS

Patients aged <17 years, enrolled in a Canadian nationwide inception cohort study, were included. Baseline demographic and IBD phenotypic features were compared between SA and Caucasian children. Longitudinal outcomes through 18 months of follow-up were compared matched by propensity scores.

RESULTS

Of 1156 children enrolled over 2014 to 2019, 623 were Caucasian [98% and 88% parents Canadian born] and 114 SA [79% Canadian born, 87% parents SA born]. Fewer SAs have a first-degree relative with IBD, 6% vs 19% in Caucasians, p = 0.002. SAs present at a younger age, median age 11.4 years (interquartile range [IQR] 9.2-14.3) vs 13 years [IQR 10.9-15 years], p = 0.03 and more commonly with a UC/IBD-U [ulcerative colitis/IBD-unclassified] subtype [ratio of UC/IBD-U to CD 1.2:1 vs 1:1.8 for Caucasians, p <0.001]. Additionally, a greater proportion of SA CD patients present with colonic-only disease [colonic-only CD/UC/IBD-U in SAs 67% vs 57% for Caucasians, p = 0.001], and among those with CD, colonic CD in SAs 31% vs 23% in Caucasians, p = 0.20]. Perianal fistulising disease was also numerically more common in SAs (14 [27%] vs 64 [18%], p = 0.06]. Adjusting for differences in phenotypic presentation, anti-tumour necrosis factor [TNF] exposure, and time to initiation was similar, and two-thirds of children, whether anti-TNF exposed or naïve, were in corticosteroid-free clinical remission at 18 months irrespective of ethnicity.

CONCLUSIONS

The phenotypic spectrum of new-onset IBD in SA children differs from that of Caucasian children, but treatment and clinical course are similar within phenotypic subgroups.

Phenotypic Variation in Paediatric Inflammatory Bowel Disease by Age: A Multicentre Prospective Inception Cohort Study of the Canadian Children IBD Network

BACKGROUND AND AIMS

Incidence of paediatric inflammatory bowel disease [IBD] in Canada is among the highest worldwide, and age of onset may be decreasing. In a multicentre nationwide inception cohort study, we examined variation in phenotype of IBD throughout the paediatric age spectrum.

METHODS

Children aged ≥2 years [y] and <17y [A1 age at diagnosis], with new onset IBD, were systematically evaluated at sites of the Canadian Children IBD Network. Prospectively recorded phenotypic data were compared between age groups.

RESULTS

Among 1092 children (70% Caucasian; 64% Crohn's disease [CD], 36% ulcerative colitis/inflammatory bowel disease unclassified [UC/IBD-U]; median age 13 y, interquartile range [IQR] 11-15 y), 210 [19%] were diagnosed before the age of age 10 y [Paris A1a] and 43 [4%] before age 6 y (very-early-onset [VEO-IBD]). CD was less common in younger children [42%, 56%, 66%, respectively, of VEO-IBD, A1a; A1b]. Colon-only IBD [UC/IBDU or CD-colon] was present in 81% of VEO-IBD and 65% of A1a; ileal disease increased progressively, reaching plateau at age 10 y. CD location was ileocolonic [L3] in 53% overall. Ileitis [L1] increased with age [6% of VEO-IBD; 13% of A1a; 21% of A1b], as did stricturing/penetrating CD [4% of A1a; 11% of A1b]. At all ages UC was extensive [E3/E4] in >85%, and disease activity moderate to severe according to Physician's Global Assessment [PGA] and weighted Paediatric Crohn's Disease Activity Index/Paediatric Ulcerative Colitis Activity Index [wPCDAI/PUCAI] in >70%. Heights were modestly reduced in CD [mean height z score -0.30 ± 1.23], but normal in UC/IBD-U.

CONCLUSIONS

Paris classification of age at diagnosis is supported by age-related increases in ileal disease until age 10 years. Other phenotypic features, including severity, are similar across all ages. Linear growth is less impaired in CD than in historical cohorts, reflecting earlier diagnosis.

Systematic review with meta-analysis: magnetic resonance enterography signs for the detection of inflammation and intestinal damage in Crohn's disease

BACKGROUND

In the treatment of Crohn's disease (CD), mucosal healing has become a major goal, with the hope of avoiding intestinal damage from chronic inflammation. Magnetic resonance enterography (MRE) has emerged as a non-invasive means of monitoring inflammation and damage.

AIMS

As part of the development of MRE-based multi-item measures of inflammation and damage for paediatric studies, we carried out a systematic review and meta-analysis to identify MRE variables used to describe these two distinct concepts.

METHODS

2501 studies of MRI and CD were identified. Studies written in any language reporting individual MRE signs for patients diagnosed with CD were included. Two-hundred-and-forty-four studies were fully reviewed and 62 were included (inflammation, n = 51; damage, n = 24). Sensitivity, specificity and associated confidence intervals were calculated, and hierarchical summary ROC curves were constructed for each MRE sign.

RESULTS

A total of 22 MRE signs were used to reflect inflammation, and 9 to reflect damage. Diagnostic accuracy of MRE signs of inflammation and damage was heterogeneous; however, wall enhancement, mucosal lesions and wall T2 hyperintensity were the most consistently useful for inflammation (most sensitivities >80% and specificities >90%), and detection of abscess and fistula were most consistently useful for damage (most sensitivities >90%, specificities >95%).

CONCLUSIONS

Identifying the best MRE variables to reflect inflammation and damage will maximise the utility of this rapidly emerging technique and is the first stage of constructing MRE-based indices for evaluating inflammation and intestinal damage.

Long-term effects of stock transfers: synergistic introgression of allochthonous genomes in salmonids

The genus Salmo was employed as a model to study introgression of genes between species due to secondary contacts. Seven microsatellite loci, the LDH-C1* locus and the 5S ribosomal DNA were studied. Results showed the mutually enhanced introgression of allochthonous genomes into southern European salmonids. This phenomenon appears to go beyond a simple consequence of the altered behaviour of domestic individuals. Invasions of autochthonous genomes by allochthonous genes would be enhanced by human activities such as stock transfers, which would simultaneously promote allochthonous and allospecific (from other species) introgressions in a synergistic process in Atlantic salmon Salmo salar and brown trout Salmo trutta. As a minor result, the data do not support the value of the microsatellite locus SsaD486 as a species-specific marker.

The first confirmed cases of full albinism in rajid species

Three albino skate specimens (Rajidae) were captured from the North Sea and English Channel between 2008 and 2011. Using DNA barcoding (COI gene) and morphometric analyses, species were identified as a spotted ray Raja montagui, a blonde ray Raja brachyura and a thornback ray Raja clavata. This finding represents the first record of full albinism (a lack of skin and retinal pigmentation) in rajid species.

Faecal calprotectin, lactoferrin, M2-pyruvate kinase and S100A12 in severe ulcerative colitis: a prospective multicentre comparison of predicting outcomes and monitoring response

OBJECTIVE

To compare four faecal markers for their ability to predict steroid refractoriness in severe paediatric ulcerative colitis (UC). Construct validity and responsiveness to change were also assessed.

METHODS

This was a prospective multicentre cohort study. Stool samples from 101 children (13.3 + or - 3.6 years; Pediatric UC Activity Index (PUCAI) at admission 72 + or - 12 points) were obtained at the third day of intravenous steroid therapy. Repeated samples at discharge were obtained from 24 children. Predictive validity was assessed using diagnostic utility statistics to predict steroid failure (ie, the need for salvage treatment). Concurrent validity was assessed using correlational analysis with the following constructs: PUCAI, Lindgren and Seo scores, physician's global assessment, albumin, erythrocyte sedimentation rate and C-reactive protein (CRP). Responsiveness was assessed using test utility and correlational strategies.

RESULTS

Median values (IQR) were very high at baseline for all four markers (calprotectin 4215 microg/g (2297-8808); lactoferrin 212 microg/g (114-328); M2-pyruvate kinase (M2-PK) 363 U/g (119-3104); and S100A12 469 microg/g (193-1112)). M2-PK was numerically superior to the other three markers and CRP in predicting response to corticosteroid treatment (area under the receiver operating characteristic (ROC) curve 0.75 (95% CI 0.64 to 0.85; p<0.001) vs <0.65 for the others). However, it did not add to the predictive ability of the PUCAI (area under the ROC 0.81 (95% CI 0.73 to 0.89)). M2-PK also had the highest construct validity but with a modest mean correlation with all constructs (r=0.3; p<0.05). None of the markers was responsive to change (Spearman's rho correlation with change in the PUCAI <0.1; p>0.05, area under the ROC curve <0.65; p>0.05).

CONCLUSIONS

The four markers were greatly elevated in severe paediatric UC. Only M2-PK had good construct and predictive validity, and none was responsive to change. The PUCAI, a simple clinical index, performed better than the faecal markers in predicting outcome following a course of intravenous corticosteroids in severe UC.

Pico-Salax versus polyethylene glycol for bowel cleanout before colonoscopy in children: a randomized controlled trial

BACKGROUND AND STUDY AIMS

Comparison of bowel preparation for colonoscopy in children with either Pico-Salax (sodium picosulphate with magnesium citrate) or polyethylene glycol with electrolyte solution (PEG-ELS).

PATIENTS AND METHODS

In this investigator-blinded, randomized controlled trial, 83 children (12.5 +/- 3.1 years) requiring elective colonoscopy at a referral hospital were randomly allocated to Pico-Salax (n = 43) or PEG-ELS (n = 40), and an intention-to treat analysis was applied. Pico-Salax was administered in two doses, one the evening before and one on the morning of the procedure. PEG-ELS was administered over 4 hours. Efficacy was scored using the Ottawa scale and other constructs. Tolerability and toxicity were measured by patient and nursing questionnaires and serum biochemistry.

RESULTS

35 of Pico-Salax patients (81 %) were satisfied or very satisfied with the cleanout, compared with 19 (48 %) in the PEG-ELS group (P = 0.001). No differences were found in bowel cleanout effectiveness, as judged by the Ottawa score (P = 0.24), completion rates (P = 0.69), colonoscopy duration (P = 0.59), need for enemas (P = 0.25), or physician's global impression (P = 0.7). Except for one case of mild dehydration in the Pico-Salax group, no clinically significant adverse events were recorded. Serum biochemistry results were similar between groups except for more hypermagnesemia associated with Pico-Salax and hypokalemia with PEG-ELS; neither was clinically significant.

CONCLUSION

Children tolerate Pico-Salax better than PEG-ELS for bowel cleanout before colonoscopy. This study did not demonstrate superiority of effectiveness or safety for either regimen.

Increasing incidence of paediatric inflammatory bowel disease in Ontario, Canada: evidence from health administrative data

OBJECTIVE

Health administrative databases can be used to track chronic diseases. The aim of this study was to validate a case ascertainment definition of paediatric-onset inflammatory bowel disease (IBD) using administrative data and describe its epidemiology in Ontario, Canada.

METHODS

A population-based clinical database of patients with IBD aged <15 years was used to define cases, and patient information was linked to health administrative data to compare the accuracy of various patterns of healthcare use. The most accurate algorithm was validated with chart data of children aged <18 years from 12 medical practices. Administrative data from the period 1991-2008 were used to describe the incidence and prevalence of IBD in Ontario children. Changes in incidence were tested using Poisson regression.

RESULTS

Accurate identification of children with IBD required four physician contacts or two hospitalisations (with International Classification of Disease (ICD) codes for IBD) within 3 years if they underwent colonoscopy and seven contacts or three hospitalisations within 3 years in those without colonoscopy (children <12 years old, sensitivity 90.5%, specificity >99.9%; children <15 years old, sensitivity 89.6%, specificity >99.9%; children <18 years old, sensitivity 91.1%, specificity 99.5%). Age- and sex-standardised prevalence per 100 000 population of paediatric IBD has increased from 42.1 (in 1994) to 56.3 (in 2005). Incidence per 100 000 has increased from 9.5 (in 1994) to 11.4 (in 2005). Statistically significant increases in incidence were noted in 0-4 year olds (5.0%/year, p = 0.03) and 5-9 year olds (7.6%/year, p<0.0001), but not in 10-14 or 15-17 year olds.

CONCLUSION

Ontario has one of the highest rates of childhood-onset IBD in the world, and there is an accelerated increase in incidence in younger children.

Polymorphisms in E-cadherin (CDH1) result in a mis-localised cytoplasmic protein that is associated with Crohn's disease

BACKGROUND

Patients with Crohn's disease have defects in intestinal epithelial permeability that are inadequately explained by known inflammatory bowel disease (IBD) susceptibility genes. E-cadherin (CDH1) plays a vital role in maintaining the integrity of the intestinal barrier and its cellular localisation is disrupted in patients with Crohn's disease.

AIM

To determine if polymorphisms in the CDH1 gene are associated with Crohn's disease and to determine the function associated with these polymorphisms.

METHODS

The hypothesis was tested using a candidate gene approach using 20 Tag SNPs derived from the HapMap and Crohn's disease trios. Functional studies were carried out using HapMap cell lines and polarised epithelial cell lines (MDCK-1 and Caco2).

RESULTS

Here we show that CDH1 is associated with Crohn's disease in 327 trios (rs10431923 excess transmission of "TT" genotype; p = 0.0020) and is replicated in the Wellcome Trust Case Control Consortium CD data set (TT risk allele; OR 1.2, p = 0.005). Patients with the Crohn's disease risk haplotype (rs12597188, rs10431923 and rs9935563; GTC allelic frequency 21%; p = 0.000016) exhibited increased E-cadherin cytoplasmic accumulation in their intestinal epithelium which may be explained by the presence of a novel truncated form of E-cadherin. Accordingly, expression of this truncated E-cadherin in cultured polarised epithelial cells resulted in abnormal intracellular accumulation and impaired plasma membrane localisation of both E-cadherin and beta-catenin.

CONCLUSION

The mis-localisation of E-cadherin and beta-catenin may explain the increased permeability seen in some patients with Crohn's disease. Thus, the polymorphisms identified in CDH1 are important for understanding the pathogenesis of Crohn's disease and point to a defect in barrier defence.

Characterization and utilization of microsatellite loci in the New World screwworm fly, Cochliomyia hominivorax

New World screwworm populations in North and Central America have been the targets of virtually continuous eradication attempts by sterile insect technique (SIT) since the 1950s. Nevertheless, in some areas, such as Jamaica, SIT control programmes have failed. Reasons for the failure of SIT-based control programmes in some locations are unknown, but it has been hypothesized that failure may be related to mating incompatibility between sterile and wild fly populations or to the existence of sexually incompatible cryptic species. This paper outlines the development of a suite of four new microsatellite loci which can be used to study intra-specific relationships between populations of Cochliomyia hominivorax from the Caribbean and South America, which represent those populations involved in, or earmarked for, forthcoming SIT control. Cross-amplification with the secondary screwworm, Cochliomyia macellaria, was also successful with three of the new loci. We present results which suggest that populations from Trinidad and Jamaica form distinct groupings of flies and that C. hominivorax from Trinidad appears particularly distinct.

Complete mitochondrial control region sequences indicate a distinct variety of brown trout Salmo trutta in the Aral Sea

Complete sequencing of the mtDNA control region (CR) from five specimens of brown trout Salmo trutta from the Amu Darya River identified two novel haplotypes belonging to the Danubian lineage. This finding supports the long-standing hypothesis that brown trout in the Aral Sea represent a distinct genetic stock and also illustrates the benefits that complete sequencing of the CR can provide for elucidating phylogeographic relationships.

Genetic variation in strains of zebrafish (Danio rerio) and the implications for ecotoxicology studies

There is substantial evidence that genetic variation, at both the level of the individual and population, has a significant effect on behaviour, fitness and response to toxicants. Using DNA microsatellites, we examined the genetic variation in samples of several commonly used laboratory strains of zebrafish, Danio rerio, a model species in toxicological studies. We compared the genetic variation to that found in a sample of wild fish from Bangladesh. Our findings show that the wild fish were significantly more variable than the laboratory strains for several measures of genetic variability, including allelic richness and expected heterozygosity. This lack of variation should be given due consideration for any study which attempts to extrapolate the results of ecotoxicological laboratory tests to wild populations.

Traditional corticosteroids for induction of remission in Crohn's disease

BACKGROUND

Historically, corticosteroids have been the most commonly used class of medication for induction of remission in Crohn's disease (CD). Corticosteroids down regulate production of inflammatory cytokines and interfere with NF-kappaB production, thereby blunting inflammatory response.

OBJECTIVES

The primary objective was to systematically review the efficacy and safety of traditional corticosteroids (given orally or intravenously) for induction of remission in CD.

SEARCH STRATEGY

The following electronic databases were searched: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, the Cochrane Inflammatory Bowel Disease and Functional Bowel Disorders (IBD/FBD) Group Specialized Trial Register, and ClinicalTrials.gov. No language restrictions were applied. Reference lists of trials and review articles, as well as recent proceedings from major gastroenterology meetings were manually searched.

SELECTION CRITERIA

Randomized, controlled clinical trials of traditional, systemic corticosteroids for the induction of remission of active CD were included in this review. Control groups included patients receiving either placebo or 5-aminosalicylates (5-ASA). The study population included patients of any age with active CD (as defined by the study authors or validated clinical activity indices), receiving any formulation of systemically available corticosteroid by any oral or parenteral methods of delivery. The primary outcome was induction of remission of CD. Secondary outcomes included clinical response, change in mean CDAI, adverse events and the proportion of patients withdrawing due to adverse events.

DATA COLLECTION AND ANALYSIS

Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality using Jadad's criteria. A random or fixed effects model was chosen based on an assessment of heterogeneity, and studies were weighted using the DerSimonian & Laird or the Mantel-Haenszel method accordingly. Meta-analysis was performed using RevMan 4.2.10 software.

MAIN RESULTS

Two studies compared corticosteroids to placebo and six studies compared corticosteroids to 5-ASA. Corticosteroids were found to be significantly more effective than placebo at inducing remission in CD (RR 1.99; 95% CI 1.51 to 2.64; P < 0.00001). Corticosteroids were found to be more effective than 5-ASA at inducing remission in studies with long follow-up duration (i.e. > 15 weeks; RR 1.65; 95% CI 1.33 to 2.03; P < 0.00001). Corticosteroids induced adverse events in a higher proportion of patients than placebo (RR 4.89; 95% CI 1.98 to 12.07; P = 0.0006), or low-dose 5-ASA (RR 2.38; 95% CI 1.34 to 4.25; P = 0.003). No difference existed in the proportion of patients experiencing adverse events when steroids were compared to high-dose 5-ASA. Steroids did not induce more study withdrawals due to adverse events than either placebo or 5-ASA.

AUTHORS' CONCLUSIONS

Corticosteroids are effective for induction of remission in patients with CD, particularly when used for more than 15 weeks. Although corticosteroids cause more adverse events than either placebo or low-dose 5-ASA, these adverse events did not lead to increased study withdrawal in the included studies. Further information is required to determine the optimal duration of treatment and tapering protocol to maximize the efficacy of treatment with corticosteroids. Additionally, further study is required to determine whether corticosteroids are more effective in patients with certain phenotypes or when administered intravenously.

Traditional corticosteroids for induction of remission in Crohn's disease

BACKGROUND

Historically, corticosteroids have been the most commonly used class of medication for induction of remission in Crohn's disease (CD). Corticosteroids down regulate production of inflammatory cytokines and interfere with NF-kappaB production, thereby blunting inflammatory response.

OBJECTIVES

The primary objective was to systematically review the efficacy and safety of traditional corticosteroids (given orally or intravenously) for induction of remission in CD.

SEARCH STRATEGY

The following electronic databases were searched: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, the Cochrane Inflammatory Bowel Disease and Functional Bowel Disorders (IBD/FBD) Group Specialized Trial Register, and ClinicalTrials.gov. No language restrictions were applied. Reference lists of trials and review articles, as well as recent proceedings from major gastroenterology meetings were manually searched.

SELECTION CRITERIA

Randomized, controlled clinical trials of traditional, systemic corticosteroids for the induction of remission of active CD were included in this review. Control groups included patients receiving either placebo or 5-aminosalicylates (5-ASA). The study population included patients of any age with active CD (as defined by the study authors or validated clinical activity indices), receiving any formulation of systemically available corticosteroid by any oral or parenteral methods of delivery. The primary outcome was induction of remission of CD. Secondary outcomes included clinical response, change in mean CDAI, adverse events and the proportion of patients withdrawing due to adverse events.

DATA COLLECTION AND ANALYSIS

Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality using Jadad's criteria. A random or fixed effects model was chosen based on an assessment of heterogeneity, and studies were weighted using the DerSimonian & Laird or the Mantel-Haenszel method accordingly. Meta-analysis was performed using RevMan 4.2.10 software.

MAIN RESULTS

Two studies compared corticosteroids to placebo and six studies compared corticosteroids to 5-ASA. Corticosteroids were found to be significantly more effective than placebo at inducing remission in CD (RR 1.99; 95% CI 1.51 to 2.64; P < 0.00001). Corticosteroids were found to be more effective than 5-ASA at inducing remission in studies with long follow-up duration (i.e. > 15 weeks; RR 1.65; 95% CI 1.33 to 2.03; P < 0.00001). Corticosteroids induced adverse events in a higher proportion of patients than placebo (RR 4.89; 95% CI 1.98 to 12.07; P = 0.0006), or low-dose 5-ASA (RR 2.38; 95% CI 1.34 to 4.25; P = 0.003). No difference existed in the proportion of patients experiencing adverse events when steroids were compared to high-dose 5-ASA. Steroids did not induce more study withdrawals due to adverse events than either placebo or 5-ASA.

AUTHORS' CONCLUSIONS

Corticosteroids are effective for induction of remission in patients with CD, particularly when used for more than 15 weeks. Although corticosteroids cause more adverse events than either placebo or low-dose 5-ASA, these adverse events did not lead to increased study withdrawal in the included studies. Further information is required to determine the optimal duration of treatment and tapering protocol to maximize the efficacy of treatment with corticosteroids. Additionally, further study is required to determine whether corticosteroids are more effective in patients with certain phenotypes or when administered intravenously.

Severe paediatric ulcerative colitis: incidence, outcomes and optimal timing for second-line therapy

BACKGROUND

Despite the predominance of extensive disease in children with ulcerative colitis, data concerning severe paediatric ulcerative colitis are sparse. We reviewed rates and predictors of response to intravenous-corticosteroid therapy in a single-centre cohort with long-term follow-up.

METHODS

99 children (49% males; age 2-17 years) were hospitalised (1991-2000) for treatment of severe ulcerative colitis (90% extensive; 49% new onset ulcerative colitis). Clinical, laboratory and radiographic data were reviewed. A population-based subset was used to assess incidence. Predictors of corticosteroid response were analysed using univariate and multivariate analyses at days 3 and 5 of therapy. Colectomy rates were calculated using Kaplan-Meier survival analyses.

RESULTS

28% (95% CI, 23 to 34%) of children with ulcerative colitis resident in the Greater Toronto Area required admission for intravenous corticosteroid therapy, of whom 53 (53%; 95% CI, 44 to 63%) responded. Several predictors were associated with corticosteroid failure, but in multivariable modelling only C-reactive protein [OR = 3.5 (1.4 to 8.4)] and number of nocturnal stools [OR = 3.2 (1.6 to 6.6)] remained significant at both days 3 and 5. The Pediatric Ulcerative Colitis Activity Index (PUCAI), Travis and Lindgren's indices strongly predicted non-response. Radiographically, the upper range of colonic luminal width was 40 mm in children younger than 11 years versus 60 mm in older patients. Cumulative colectomy rates at discharge, 1 year and 6 years were 42%, 58% and 61%, respectively.

CONCLUSIONS

Children with ulcerative colitis commonly experience at least one severe exacerbation. Response to intravenous corticosteroids is poor. The PUCAI, determined at day 3 (>45 points) should be used to screen for patients likely to fail corticosteroids and at day 5 (>70 points) to dictate the introduction of second-line therapies.

Omega 3 fatty acids (fish oil) for maintenance of remission in ulcerative colitis

BACKGROUND

Omega-3 fatty acids (n-3, fish oil) have been shown to have anti-inflammatory properties. Therefore, n-3 therapy may be beneficial in chronic inflammatory disorders such as ulcerative colitis.

OBJECTIVES

To systematically review the efficacy and safety of n-3 for maintaining remission in ulcerative colitis (UC).

SEARCH STRATEGY

The following databases were searched from their inception without language restriction: Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Healthstar, PubMed, and ACP journal club. Experts were contacted for unpublished data.

SELECTION CRITERIA

Randomized placebo-controlled trials (RCT) of fish oil for maintenance of remission in UC were included. Studies must have enrolled patients (of any age group) who were in remission at the time of recruitment, and were followed for at least six months. The intervention must have been fish oil given in pre-defined dosage. Co-interventions were allowed only if they were balanced between the study groups. The primary outcome was relapse rate and the secondary outcome was frequency of adverse events. Other outcomes to assess efficacy were change in disease activity scores and time to first relapse.

DATA COLLECTION AND ANALYSIS

Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality. Meta-analysis weighted by the Mantel-Haenszel method was performed using RevMan 4.2.8 software. Random or fixed effect models were used according to degree of heterogeneity and subgroup analyses were performed to explore heterogeneity. A sensitivity analysis was performed excluding a study of questionable quality .

MAIN RESULTS

The three studies that were included used different formulation and dosing of n-3 but none used enteric coated capsules. The pooled analysis showed a similar relapse rate in the n-3 treated patients and controls (RR 1.02; 95% CI 0.51 to 2.03; P = 0.96). Combining the studies resulted in virtually no statistical heterogeneity (P = 0.93, I(2) = 0%). Various subgroup and sensitivity analyses showed similar results. However, the total number of patients enrolled in these studies was small (n = 138). No significant adverse events were recorded in any of the studies and not enough data were available to pool the other secondary outcomes for meta-analysis.

AUTHORS' CONCLUSIONS

No evidence was found that supports the use of omega 3 fatty acids for maintenance of remission in UC. Further studies using enteric coated capsules may be justified.

Omega 3 fatty acids (fish oil) for maintenance of remission in Crohn's disease

BACKGROUND

The anti-inflammatory effects of n-3 (omega-3 fatty acids, fish oil) have been suggested to be beneficial in chronic inflammatory disorders such as inflammatory bowel disease.

OBJECTIVES

To systematically review the efficacy and safety of n-3 for maintaining remission in Crohn's disease (CD).

SEARCH STRATEGY

The following databases were searched from their inception without language restriction: Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Healthstar, PubMed, and ACP journal club. Experts were contacted for unpublished data.

SELECTION CRITERIA

Randomized placebo-controlled trials (RCT) of n-3 for maintenance of remission in CD were included. Studies must have enrolled patients of any age group, who were in remission at the time of recruitment, and were followed for at least six months. The intervention must have been fish oil or n-3 given in pre-defined dosage. Co-interventions were allowed only if they were balanced between the study groups. The primary outcome was relapse rate and secondary outcomes were change in disease activity scores, time to first relapse and adverse events.

DATA COLLECTION AND ANALYSIS

Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality using Jadad's criteria. Meta-analysis was performed using RevMan 4.2 software, weighted by the Mantel-Haenszel method. Random or fixed effect models were used according to degree of heterogeneity and subgroup analyses were performed to address heterogeneity.

MAIN RESULTS

Four studies were eligible for inclusion. There was a non statistically significant benefit of n-3 therapy for maintaining remission (RR 0.64; 95%CI 0.4 to 1.03; P = 0.07). However, the studies were both clinically and statistically heterogeneous (P = 0.01, I(2) = 72%). Three studies used enteric coated capsules (positive effects) and one ordinary gelatin capsules (no advantage). Subgroup analyses of studies which used enteric coated capsules revealed a statistically significant benefit for maintenance of remission (RR 0.49; 95% CI 0.35 to 0.69; RD 0.31; 95% CI 0.19 to 0.43); number needed to treat to prevent relapse in 1 year was 3 (95% CI 2 to 5; I(2) = 19%). However, the total number of patients enrolled in these studies was small (n = 166). No significant adverse events were recorded in any of the studies and not enough data were available to analyze the other secondary outcomes.

AUTHORS' CONCLUSIONS

Omega 3 fatty acids are safe and may be effective for maintenance of remission in CD when used in enteric coated capsules. However, there are not sufficient data to recommend the routine use of n-3 for maintenance of remission in CD. The small number of patients in the included studies warrants further larger RCTs.

Enteral nutritional therapy for induction of remission in Crohn's disease

BACKGROUND

The role of enteral nutrition in Crohn's disease is controversial. Increasing research on the mechanisms by which nutritional therapy improves the clinical well being of patients with Crohn's disease has led to novel formula design and trials comparing two different forms of enteral nutrition. This meta-analysis aims to provide an update on the existing effectiveness data for both corticosteroids versus enteral nutrition and for one form of enteral nutrition versus another for inducing remission of active Crohn's disease.

OBJECTIVES

To evaluate the effectiveness of exclusive enteral nutrition (EN) as primary therapy to induce remission in Crohn's disease and to examine the importance of formula composition on effectiveness.

SEARCH STRATEGY

Studies were selected using a computer-assisted search of the on-line bibliographic databases MEDLINE (1966-2006) and EMBASE (1984-2006), as well as the Science Citation Index on Web of Science. Additional citations were sought by manual search of references of articles retrieved from the computerized search, abstracts submitted to major gastroenterologic meetings and published in the journals: American Journal of Gastroenterology, Gut, Gastroenterology, Journal of Pediatric Gastroenterology and Nutrition, and Journal of Parenteral and Enteral Nutrition, and from the reviewers' personal files or contact with leaders in the field.

SELECTION CRITERIA

All randomized and quasi-randomized controlled trials involving patients with active Crohn's disease defined by a clinical disease activity index were considered for review. Studies evaluating the administration of one type of enteral nutrition to one group of patients and another type of enteral nutrition or conventional corticosteroids to the other group were selected for review.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two authors and any discrepancies were resolved by rereading and discussion. For the dichotomous variable, achievement of remission, individual and pooled trial statistics were calculated as odds ratios (OR) with 95% confidence intervals (CI); both fixed and random effect models were used. The results for each analysis were tested for heterogeneity using the chi square statistic. The studies were separated into two groups: A. one form of enteral nutrition compared with another form of enteral nutrition and B. one form of enteral nutrition compared with corticosteroids. Subgroup analyses were conducted on the basis of clinical or disease criteria and formula composition. Sensitivity analyses were conducted on the basis of the inclusion of abstract publications, methodologic quality and by random or fixed effects models.

MAIN RESULTS

In part A, of the 15 included eligible trials (one abstract) comparing different formulations of EN for the treatment of active CD, 11 compared one (or more) elemental formula to a non-elemental one, three compared enteral diets of similar protein composition but different fat composition, and one compared non-elemental diets differing only in glutamine enrichment. Meta-analysis of ten trials comprising 334 patients demonstrated no difference in the efficacy of elemental versus non-elemental formulas (OR 1.10; 95% CI 0.69 to 1.75). Subgroup analyses performed to evaluate the different types of elemental and non-elemental diets (elemental, semi-elemental and polymeric) showed no statistically significant differences. Further analysis of seven trials including 209 patients treated with EN formulas of differing fat content (low fat: < 20 g/1000 kCal versus high fat: > 20 g/1000 kCal) demonstrated no statistically significant difference in efficacy (OR 1.13; 95% CI 0.63 to 2.01). Similarly, the effect of very low fat content (< 3 g/1000 kCal) or type of fat (long chain triglycerides) were investigated, but did not demonstrate a difference in efficacy in the treatment of active CD, although a non significant trend was demonstrated favoring very low fat and very low long chain triglyceride content. This result should be interpreted with caution due to statistically significant heterogeneity and small sample size. Sensitivity analyses had no significant effects on the results. The role of specific fatty acids or disease characteristics on response to therapy could not be evaluated. In part B, eight trials (including two abstracts) comparing enteral nutrition to steroid therapy met the inclusion criteria for review. Meta-analysis of six trials that included 192 patients treated with enteral nutrition and 160 treated with steroids yielded a pooled OR of 0.33 favouring steroid therapy (95% CI 0.21 to 0.53). A sensitivity analysis including the abstracts resulted in an increase in the number of participants to 212 in the enteral nutrition group and 179 in the steroid group but the meta-analysis yielded a similar result (OR 0.36; 95% CI 0.23 to 0.56). There were inadequate data from full publications to perform further subgroup analyses by age, disease duration and disease location.

AUTHORS' CONCLUSIONS

Corticosteroid therapy is more effective than enteral nutrition for inducing remission of active Crohn's disease as was found in previous systematic reviews. Protein composition does not influence the effectiveness of EN in the treatment of active CD. A non significant trend favouring very low fat and/or very low long chain triglyceride content exists but larger trials are required to explore the significance of this finding.

Gastral antral biopsy in the differentiation of pediatric colitides

OBJECTIVES

Differentiation of Crohn's disease (CD) from ulcerative colitis (UC) is problematic, primarily when inflammation is confined to the colon. In a historical cohort study, we evaluated the usefulness of baseline gastric antral biopsies in the differentiation of pediatric chronic colitides.

METHODS

During initial investigation for suspected inflammatory bowel disease, 39 children and adolescents with colitis but normal small bowel radiography underwent pretreatment upper endoscopy concurrently with colonoscopy. Two reviewers assigned a colonoscopic diagnosis (colonic CD, UC, or indeterminate colitis) based on the macroscopic and microscopic appearances of the colonic mucosa. Antral histological findings were compared between groups using Fisher's exact test.

RESULTS

Five (14%) of colonoscopic diagnoses (four indeterminate, one UC) were changed to CD by the finding of granulomatous inflammation in antral biopsies. Nonspecific antral gastritis was found in similar proportions of children and adolescents with Crohn's colitis and UC (92% vs 75%). Focal antral gastritis was more common in patients with Crohn's colitis than UC (52% vs 8%).

CONCLUSIONS

Nonspecific antral gastritis is common in all forms of chronic colitis. Nevertheless, upper gastrointestinal endoscopy with biopsy is useful in the differentiation of inflammatory bowel disease confined to the colon, particularly when colonoscopic findings are indeterminate.

A critical assessment of items on the Pediatric Crohn's Disease Activity Index

OBJECTIVES

Questions have been raised about the discriminative value of the three laboratory items (hematocrit, erythrocyte sedimentation rate, and albumin) and three physical items (height, perirectal disease, and extraintestinal manifestations) included in the Pediatric Crohn's Disease Activity Index (PCDAI). The aim of this study was to analyze the value of these six "criticized" items to the discriminative properties of the PCDAI.

METHODS

Data from 71 children with Crohn's disease visiting an outpatient clinic were analyzed. Physician global assessment of disease activity was used as the gold standard. A "basic index" was calculated by subtracting the score of the six criticized items from the score of the PCDAI calculated in the standard fashion. Multivariate logistic regression procedures identified which items significantly contributed to the "basic index". Receiver operating characteristic curves were produced comparing the standard PCDAI score to the "basic index" and a new "clinical index" which included only the criticized items truly contributing to the discriminatory ability of the "basic index".

RESULTS

Logistic regression models identified only perirectal disease as contributing to the discriminative abilities of the basic index. The clinical index therefore consists of the three history items (abdominal pain, number of liquid stools, and general well-being), three physical examination items (weight loss, abdominal examination, and perirectal disease) and no laboratory tests. The clinical index had an area under the curve not significantly inferior to that of the original PCDAI (0.93 [95% confidence interval, 0.89-0.99] vs. 0.96 [95% confidence interval, 0.92-0.99]).

CONCLUSIONS

A clinical index consisting of three history items and three physical examination items has an accuracy equal to the standard PCDAI in distinguishing children with disease in remission from those with a relapse.

Pediatric Crohn Disease Activity Index: responsive to short-term change

BACKGROUND/AIMS

Despite documented feasibility, reliability, and validity, the Pediatric Crohn's Disease Activity Index (PCDAI) has yet to be demonstrated to be sensitive to change in the time frame of acute treatment trials. We evaluated short-term responsiveness and determined the minimal change in PCDAI score associated with a clinically meaningful improvement in disease activity.

METHODS

Standardized effect size (SES) and standardized response mean (SRM) were calculated as measures of responsiveness among pediatric patients being treated for acute exacerbations of Crohn disease 1) in a regular clinical practice setting and 2) as part of a multicenter, randomized controlled trial (RCT). Receiver operating characteristic (ROC) curves were constructed to determine the minimal PCDAI score change associated with significant clinical improvement used as the gold standard in 1) physician global assessment of change and in 2) change in adult Crohn disease activity index (CDAI).

RESULTS

Among responders, the SES and SRM of the PCDAI were 1.78 and 1.41 (95% CI: 0.89-1.92) and 2.10 and 1.95 (95% CI: 1.70-2.20) in the clinical practice setting and RCT setting, respectively. The optimal minimal PCDAI change score associated with clinically significant change in physician global assessment was determined to be -12.5 (sensitivity 83.3%, specificity 92.3%). In the RCT setting a change in PCDAI of -10 corresponded to a change in CDAI of not greater-than-or-equal 70 points.

CONCLUSIONS

The PCDAI is responsive to improvement in disease activity in Crohn disease patients over a short interval. As such, the PCDAI is an appropriate instrument to use in pediatric acute treatment trials.

Genetic variation in the 5q31 cytokine gene cluster confers susceptibility to Crohn disease

Linkage disequilibrium (LD) mapping provides a powerful method for fine-structure localization of rare disease genes, but has not yet been widely applied to common disease. We sought to design a systematic approach for LD mapping and apply it to the localization of a gene (IBD5) conferring susceptibility to Crohn disease. The key issues are: (i) to detect a significant LD signal (ii) to rigorously bound the critical region and (iii) to identify the causal genetic variant within this region. We previously mapped the IBD5 locus to a large region spanning 18 cM of chromosome 5q31 (P<10(-4)). Using dense genetic maps of microsatellite markers and single-nucleotide polymorphisms (SNPs) across the entire region, we found strong evidence of LD. We bound the region to a common haplotype spanning 250 kb that shows strong association with the disease (P< 2 x 10(-7)) and contains the cytokine gene cluster. This finding provides overwhelming evidence that a specific common haplotype of the cytokine region in 5q31 confers susceptibility to Crohn disease. However, genetic evidence alone is not sufficient to identify the causal mutation within this region, as strong LD across the region results in multiple SNPs having equivalent genetic evidence-each consistent with the expected properties of the IBD5 locus. These results have important implications for Crohn disease in particular and LD mapping in general.

Controlled ileal release budesonide in pediatric Crohn disease: efficacy and effect on growth

BACKGROUND

Although the effectiveness of controlled ileal release (CIR) budesonide in children can be extrapolated from adult studies, there are currently no data available concerning the effects of CIR budesonide therapy on linear growth. In the absence of controlled, prospective pediatric clinical trials, we reviewed the outcomes, particularly linear growth, of children and adolescents given CIR budesonide to treat active intestinal inflammation and to maintain remission.

METHODS

Thirty-two children (20 males) aged 14.1 +/- 2.7 years with Crohn disease of the distal ileum with or without right colon involvement were treated for active Crohn disease (baseline Pediatric Crohn Disease Activity Index, 34 +/- 14) with 9 mg daily of CIR budesonide through the Hospital for Sick Children, University of Toronto, Inflammatory Bowel Diseases program.

RESULTS

At first follow-up visit 8.7 +/- 6.0 weeks later, 19 of 32 (59%) were judged by the physician to have responded. In the subset of 22 patients who had laboratory tests repeated at the first follow-up visit, their Pediatric Crohn Disease Activity Index fell from 33 +/- 14 to 22 +/- 16 (P = 0.001). The Pediatric Crohn Disease Activity Index score fell to less than 15 (cut-off score remission) in 29%. Six prepubertal responders continued to receive 6 mg CIR budesonide for 6 to 13 months. Five of the 6 experienced only mild or no gastrointestinal symptoms and gained weight. Nevertheless, their mean height velocity was only 2.3 +/- 1.0 cm/year, and none grew at a rate of more than 4cm/year whilst receiving CIR budesonide.

CONCLUSIONS

These data provide grade III evidence of modest effectiveness of CIR budesonide in children with active Crohn disease confined to the ileum with or without right colon involvement. The subnormal growth observed with continued therapy is concerning and may reflect either inadequately controlled intestinal inflammation or direct suppression of linear growth, as is observed with conventional corticosteroids. Randomized controlled pediatric trials of CIR budesonide must include parameters of linear growth as an outcome variable.

Quality of life in inflammatory bowel disease: a cross-cultural comparison of English and Canadian children

BACKGROUND

Any disease and its treatment has an important impact on health-related quality of life for affected individuals. There have been few previous studies on the quality of life for children with inflammatory bowel disease (IBD).

METHODS

A cross-cultural comparison was performed to determine whether the concerns of children with IBD in the United Kingdom are ranked similarly to those of children with IBD in Canada. An item reduction questionnaire, developed from interviews with Canadian children with IBD, was scored by 53 British children with IBD for importance and frequency, as a questionnaire had been scored previously by 117 Canadian children.

RESULTS

There was a significant correlation between the mean scores (r = 0.831, P < 0.001) and ranks (r = 0.801, P < 0.001) for the 96 questions, and 43 of the 50 highest-ranking concerns corresponded for both populations. Confidence interval analysis showed a significant difference between the mean values for 21 of the 96 items; 20 of these 21 were ranked higher in the United Kingdom than they had been in Canada, suggesting that the frequency and/or degree of concern was greater for the British children with IBD.

CONCLUSIONS

Health-related concerns of British children with Crohn disease and ulcerative colitis correlate closely with those of Canadian children with those diseases. Further studies are needed to determine the sensitivity of individual questions, the most appropriate wording of these questions, and the optimal length for a proposed instrument to assess quality of life in children with IBD.

Repeated doses of porcine secretin in the treatment of autism: a randomized, placebo-controlled trial

BACKGROUND AND OBJECTIVES

Anecdotal reports on the efficacy of secretin in autism raised great hopes for the treatment of children with this disorder. Initial single-dose, randomized, controlled trials failed to demonstrate any therapeutic effects of secretin. The present study is the first to test the outcome of repeated doses and to examine whether there is a subgroup of children who are more likely to achieve positive effects.

METHOD

Sixty-four children with autism (ages 2-7 years; 55 boys and 9 girls) with a range of intelligence quotient and verbal ability were randomly assigned, in a double-blind manner, to secretin or placebo groups. Children received 2 doses of placebo or porcine secretin, 6 weeks apart. Assessments were performed at baseline and 3 weeks after each injection using several outcome measures.

RESULTS

There were no group differences on formal measures of language, cognition, or autistic symptomatology. Subgroupings based on cognitive level, the presence or absence of diarrhea, or a history of regression failed to show any significant therapeutic effects of secretin.

CONCLUSION

No evidence is provided for the efficacy of repeated doses of porcine secretin in the treatment of children with autism. The possible relationship between relief of biological symptoms and enhanced skill performance is discussed.

Enteral nutritional therapy for inducing remission of Crohn's disease

BACKGROUND

The role of enteral nutrition in Crohn's disease is controversial. Increasing research on the mechanisms by which nutritional therapy improves the clinical well being of patients with Crohn's disease has led to novel formula design and trials comparing two different forms of enteral nutrition. This systematic review aims to provide an update on the existing efficacy data for both corticosteroids versus enteral nutrition and for one form of enteral nutrition versus another for inducing remission of active Crohn's disease.

OBJECTIVES

To evaluate the efficacy of exclusive enteral nutrition as primary therapy to induce remission in Crohn's disease and to examine the importance of formula composition on efficacy.

SEARCH STRATEGY

Studies were selected using a computer-assisted search of the on-line bibliographic databases MEDLINE (1966-2000) and EMBASE (1984-2000), as well as the Science Citation Index on Web of Science. Additional citations were sought by manual search of references of articles retrieved from the computerized search, abstracts submitted to major gastroenterologic meetings and published in the journals: Gut, Gastroenterology, Journal of Pediatric Gastroenterology and Nutrition, and Journal of Parenteral and Enteral Nutrition, and from the reviewers' personal files or contact with leaders in the field.

SELECTION CRITERIA

All randomized and quasi-randomized controlled trials involving patients with active Crohn's disease defined by a clinical disease activity index were considered for review. Studies evaluating the administration of one type of enteral nutrition to one group of patients and another type of enteral nutrition or conventional corticosteroids to the other group were selected for review.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two reviewers and any discrepancies were resolved by rereading and discussion. For the dichotomous variable, achievement of remission, individual and pooled trial statistics were calculated as odds ratios (OR) with 95% confidence intervals (CI); both fixed and random effect models were used. The results for each analysis were tested for heterogeneity using the chi square statistic. The studies were separated into two groups: A. one form of enteral nutrition compared with another form of enteral nutrition and B. one form of enteral nutrition compared with corticosteroids. Subgroup analyses were conducted on the basis of clinical or disease criteria and formula composition. Sensitivity analyses were conducted on the basis of the inclusion of abstracts of studies not yet fully published, methodologic quality and by random or fixed effects models.

MAIN RESULTS

In part A, of the 11 trials (one abstract) comparing different formulations of enteral nutrition ten compared one [or more (Middleton (a)1995)] elemental formulas to a non-elemental diet. The eleventh study (Akobeng 2000) compared two non-elemental diets differing only by glutamine enrichment in one group. This study was therefore not included in the primary analysis but was part of the subgroup analyses. Meta-analysis of nine studies which included 170 patients treated with an elemental diet and 128 patients treated with a non-elemental diet for active Crohn's disease demonstrated no significant difference among diet formulations [OR 1.15 (95% CI: 0.64, 2.08)]. Significant heterogeneity was not present [chi-square 9.77 (df=8)]. Subgroup and sensitivity analyses had no significant effect on the results. In part B, six trials (two abstracts) comparing enteral nutrition to steroid therapy met the inclusion criteria for review. Meta-analysis of four trials that included 130 patients treated with enteral nutrition and 123 treated with steroids yielded a pooled OR of 0.30 favouring steroid therapy (95% CI: 0.17, 0.52). Heterogeneity was not demonstrated [chi-square 0.43 (df=3)]. The risk difference calculated from this meta-analysis was 0.26, and the NNT (number of patients needed to treat with steroids rather than enteral nutrition to achieve one remission) was four. The same result was found in a sensitivity analysis that included abstracts. The inclusion of abstracts resulted in an increase in the number of participants to 150 in the enteral nutrition group and 142 in the steroid group but the meta-analysis yielded a similar result [OR 0.34 (95% CI: 0.20, 0.56)]. There were inadequate data from full publications to perform further subgroup analyses by age, disease duration and disease location.

REVIEWER'S CONCLUSIONS

Corticosteroid therapy is more effective than enteral nutrition for inducing remission of active Crohn's disease as was found in past meta-analyses. There is no significant difference in the efficacy of elemental and non-elemental diets for induction of remission of Crohn's disease.

Oral tacrolimus treatment of severe colitis in children

OBJECTIVE

To evaluate the efficacy of oral tacrolimus as an induction agent in steroid-refractory severe colitis.

STUDY DESIGN

Open-label, multicenter trial of oral tacrolimus in patients with severe colitis. Patients not responding to conventional therapy received tacrolimus, 0.1 mg/kg/dose given twice a day, and the dosage was adjusted to achieve blood levels between 10 and 15 ng/mL. Response was defined as improvement in a number of clinical parameters (including abdominal pain, diarrhea, rectal bleeding, and cessation of transfusions). Patients who responded by 14 days continued to receive tacrolimus, and 6-mercaptopurine or azathioprine was added as a steroid-sparing agent 4 to 6 weeks after the tacrolimus was instituted.

RESULTS

Fourteen patients were enrolled in the study. One patient elected to withdraw after 48 hours. Of the 13 remaining, 9 (69%) responded and were discharged. Tacrolimus was continued for 2 to 3 months in the responders, except for 1 patient who was given tacrolimus for 11 months. After 1 year of follow-up, only 5 (38%) patients were receiving maintenance therapy; the other 4 responders had undergone colectomy.

CONCLUSION

Although tacrolimus is effective induction therapy for severe ulcerative or Crohn's colitis, fewer than 50% of patients treated will successfully achieve a long-term remission.

Nutrition in inflammatory bowel disease

Recent developments concerning nutritional complications of inflammatory bowel disease include a better understanding of disease-associated anorexia and increasing recognition of the interaction of nutrition and cytokines in the pathogenesis of growth impairment of children. Decreased bone mineral density is a multifactorial complication and an increased focus of research. Enteral nutrition continues to play an important role in the therapy of Crohn's disease. The mechanisms whereby specific nutrients, such as n-3 fatty acids, antioxidants, and butyrate, ameliorate inflammation are being elucidated in in-vitro studies, but beneficial effects have yet to be translated into the clinical sphere.

Genomewide search in Canadian families with inflammatory bowel disease reveals two novel susceptibility loci

The chronic inflammatory bowel diseases (IBDs)-Crohn disease (CD) and ulcerative colitis (UC)-are idiopathic, inflammatory disorders of the gastrointestinal tract. These conditions have a peak incidence in early adulthood and a combined prevalence of approximately 100-200/100,000. Although the etiology of IBD is multifactorial, a significant genetic contribution to disease susceptibility is implied by epidemiological data revealing a sibling risk of approximately 35-fold for CD and approximately 15-fold for UC. To elucidate the genetic basis for these disorders, we undertook a genomewide scan in 158 Canadian sib-pair families and identified three regions of suggestive linkage (3p, 5q31-33, and 6p) and one region of significant linkage to 19p13 (LOD score 4.6). Higher-density mapping in the 5q31-q33 region revealed a locus of genomewide significance (LOD score 3.9) that contributes to CD susceptibility in families with early-onset disease. Both of these genomic regions contain numerous genes that are important to the immune and inflammatory systems and that provide good targets for future candidate-gene studies.

Analysis of the effects of increasing delivered dialysis treatment to malnourished peritoneal dialysis patients

BACKGROUND

Poor nutrition is associated with a loss of residual renal function and inferior clinical outcome in peritoneal dialysis (PD) patients. The value of increasing the PD dose in these individuals is unclear.

METHODS

An open, prospective, longitudinal, "intention to treat" study was performed on a whole PD population. All patients treated during an 18-month recruitment period underwent nutritional assessment and were defined as malnourished if they had a subjective global assessment (SGA) of B or C and were 5% or more below their desirable body weight. These patients received an intended dialysis dose increase of 25% and were reassessed after six months. Dialysis was not increased in the remaining patients, unless dictated by uremic symptoms.

RESULTS

Forty-eight of 153 patients were malnourished by the previously mentioned criteria. When compared with well-nourished PD patients, they had evidence of declining nutrition over the previous 12 months, as judged by a loss in body weight and mid-arm circumference (MAC), a reduced creatinine appearance, a reduced appetite for protein and calories, and low plasma albumin. They had been on treatment longer and had less residual renal function, resulting in significantly poorer solute clearances. Their peritoneal membrane function, plasma bicarbonate, comorbid, Karnofsky, Hospital Anxiety and Depression (HAD) scores were not different. Following intervention, their peritoneal Kt/Vurea was increased by 22.5%, and their total Kt/Vurea by 18%, because of a continued loss of residual function. There was also an increase in dialysis-derived calories. Weight and MAC stabilized after an initial deterioration, and creatinine appearance increased. There was no increase in protein intake, as judged by dietetic interview or protein nitrogen appearance. Oral calorie intake improved, as did plasma albumin after an initial decline. Both of these improvements were correlated with the achieved increase in Kt/Vurea. Objective measures of improvement (plasma albumin and protein nitrogen appearance) were significant in those patients without comorbid disease.

CONCLUSIONS

These results support the existing evidence that malnutrition is acquired on PD in those patients who lose residual renal function. It is feasible to increase the dialysis dose in these individuals without a detrimental effect, and there is evidence of a modest benefit in patients without comorbidity.

Magnetic resonance imaging to distinguish the type and severity of pediatric inflammatory bowel diseases

BACKGROUND

The distinction between ulcerative colitis and Crohn's disease is important, because treatment options and clinical course may vary. Magnetic resonance imaging (MRI) allows noninvasive transmural assessment of the intestine and may facilitate differentiation of ulcerative colitis from Crohn's disease. The objective of this prospective study was to determine whether MRI differentiates Crohn's disease from ulcerative colitis in children as effectively as colonoscopy with mucosal biopsies.

METHODS

Fifteen patients underwent colonoscopy with biopsies followed by abdominal MRI. The MRI diagnosis, determined by two radiologists independently completing a standardized form was compared with the gastroenterologic diagnosis.

RESULTS

After colonoscopy and review of histology, Crohn's disease was diagnosed in nine patients, ulcerative colitis in five, and indeterminate colitis in one, who was excluded from study. Agreement of the MRI diagnosis with the gastroenterologic diagnosis was 4 of 4 (100%) for ulcerative colitis, 4 of 10 (40%) for Crohn's disease considering both radiologists, and 5 of 10 (50%) for Crohn's disease for each radiologist individually. Percentage of enhancement by MRI did not correlate with the severity of inflammation determined at endoscopy among the patients with Crohn's disease (r = -0.3, P = 0.366). There was agreement on severity of inflammation in three of four patients with ulcerative colitis.

CONCLUSIONS

Current MRI interpretation of inflammatory bowel disease did not adequately recognize Crohn's disease in children. Therefore, colonoscopy with biopsy remains the most accurate tool for determining the type and severity of inflammatory bowel disease in children and adolescents.

Corticosteroids for maintaining remission of Crohn's disease

OBJECTIVES

To evaluate the effectiveness and safety of conventional systemic corticosteroid therapy in maintaining clinical remission in Crohn's disease.

SEARCH STRATEGY

A computer-assisted search of the on-line bibliographic database MEDLINE of studies published in English, French, Spanish, Italian and German between 1966 and May, 1998. Manual searches of the reference lists from the potentially relevant studies were performed in order to identify additional studies that may have been missed using the computer-assisted search strategy. Proceedings from major gastrointestinal meetings were also manually searched from 1985 to 1997 in order to identify unpublished studies. The Cochrane Controlled Trials Register and the Inflammatory Bowel Disease Review Group Trials Register were also searched.

SELECTION CRITERIA

Randomized double-blind placebo-controlled trials involving patients of any age with Crohn's disease in clinical remission as defined by a CDAI < 150 or by the presence of no symptoms or only mild symptoms at the time of entry into the trial. The experimental treatment consisted of oral conventional corticosteroid therapy (excluding budesonide, fluticasone, etc). Clinical disease relapse was used as the outcome measure of interest.

DATA COLLECTION AND ANALYSIS

Eligible studies were selected by 4 reviewers and data were extracted onto standardized data extraction forms. Disagreements in eligibility or data extraction were resolved by consensus. Data were converted into individual 2x2 tables for each study. The presence of significant heterogeneity among studies was tested using the chi-square test. The 2x2 tables were synthesized into a summary test statistic using the pooled odds ratio and 95% confidence intervals as described by Cochran and Mantel and Haenszel (the 'odds ratio' in MetaView). A fixed effects model was used for the pooling of data.

MAIN RESULTS

Four studies were initially judged as being eligible for inclusion. After obtaining additional information on one of the studies it was excluded because it was not double-blind. The total number of subjects included in the analysis at the time points of 6, 12 and 24 months were 142, 131 and 95 for the corticosteroid group and 161, 138 and 87 for the control group. The odds ratios for relapse on active treatment and the corresponding 95% confidence intervals were 0.71 (0.39, 1.31), 0.82 (0.47, 1.43) and 0.72 (0.38, 1.35) at 6, 12 and 24 months. The numbers needed to treat with corticosteroids to prevent one additional relapse were 24, 35, 15 respectively.

REVIEWER'S CONCLUSIONS

The use of conventional systemic corticosteroids in patients with clinically quiescent Crohn's disease does not appear to reduce the risk of relapse over a 24 month period of follow-up.

Impact of peritoneal membrane function on long-term clinical outcome in peritoneal dialysis patients

It is increasingly clear that peritoneal membrane transport status has clinical implications. The role of the peritoneum in dialysis delivery becomes paramount once residual renal function is lost, particularly as the membrane characteristics may change for the worse with time on treatment. These findings have several important implications: Clinicians need to take solute transport characteristics into account as they assess their patients. Adverse effects of high solute transport include reduced ultrafiltration, solute removal (in particular, sodium), and increased peritoneal protein losses. A need exists to replace lost residual renal function, not just with enhanced solute removal, but also with adequate salt and water removal. The interpretation of urea and creatinine clearances in anuric PD patients needs further consideration and validation. Hypoalbuminemia in PD patients will result from the combined effects of high protein losses, over-hydration, comorbidity, and malnutrition.

Development of a quality-of-life index for pediatric inflammatory bowel disease: dealing with differences related to age and IBD type

BACKGROUND

A child- and adolescent-generated IBD quality-of-life index was designed to be descriptive (to be used to assess the overall impact of IBD on individual patients), and evaluative (to be used as an outcome measure in clinical trials).

METHODS

Item-generation and item-reduction interviews with 82 patients with IBD aged 8 to 17 years (61 with Crohn's disease, 21 with ulcerative colitis; 36 girls, 45 boys) generated a list of ways in which their lives were affected by IBD. These issues were incorporated into an item-reduction questionnaire, which was administered to 117 patients (87 Crohn's disease, 30 ulcerative colitis). Patients indicated on a visual analog scale how important an item was to them and how often it bothered them. Mean and median importance-plus-frequency scores for each issue were calculated for the entire group and among patients in subgroups according to age and IBD type.

RESULTS

Ulcerative colitis and Crohn's disease affect the lives of children and adolescents differently. Bowel symptoms are more troubling and disabling to patients with ulcerative colitis, whereas systemic symptoms and body image concerns are greater for patients with Crohn's disease. The impact of Crohn's disease on ability to function in school and leisure activities is greater. Worries about future health problems and about the effects of IBD on the family are shared. Crohn's disease and ulcerative colitis trigger emotional responses of unfairness and frustration, but anger and embarrassment are more prevalent in ulcerative colitis. Disparities between age groups are fewer and less marked than those between types of IBD.

CONCLUSION

In selection of items to be retained in a pediatric IBD quality-of-life measure, the variation in concerns with disease type must be considered. A single index to assess IBD-related quality of life must include items of major importance to one subgroup of patients, even if not important to all. Alternately, a core of common concerns could be supplemented by disease-specific modules, thereby increasing the content validity of the tool for all patients.