The natural history of pediatric-onset IBD-unclassified and prediction of Crohn's disease reclassification: a 27-year study

Influence of Familial Inflammatory Bowel Disease History on the Use of Immunosuppressants, Biological Agents and Surgery in Patients with Pediatric-Onset of the Disease in the Era of Biological Therapies. Results from the ENEIDA Registry

Background: Pediatric-onset familial inflammatory bowel disease (IBD) may differ from sporadic pediatric-onset IBD in its genetic and environmental background and may have distinct clinical and therapeutic implications. Objective: To evaluate the influence of a positive family history of IBD on the use of medical therapies and surgical interventions in adult patients with pediatric-onset IBD. Methods: Retrospective case-control study using the Spanish ENEIDA registry, including adults diagnosed with pediatric-onset IBD since 2006. Familial forms (FFs) (defined by a first-degree relative with IBD) and sporadic forms (SF) (with no relatives of any grade with IBD) were matched 1:4 by type of IBD, sex, age at IBD diagnosis, disease location, disease pattern, development of perianal disease and smoking status at diagnosis. The study outcomes were the use of immunomodulators, biological therapies, intestinal surgery, and perianal surgery during follow-up. Results: Six-hundred and fifty-five Crohn's disease (CD) (131 FF) and 440 ulcerative colitis (UC) (88 FF) patients were included. Immunomodulators, biological therapy, and intestinal surgery were used evenly among FF and SF patients for both UC and CD. However, a higher requirement for perianal surgery among FF-CD patients (18.3% vs. 10.5%, p = 0.014), together with a shorter time to perianal surgery (11 vs. 20 months, log-rank p = 0.004), was observed. Conclusions: Patients with FF of pediatric-onset IBD do not exhibit an increased use of immunomodulators, biological agents, or intestinal surgery, but do exhibit a higher need for perianal surgery, as compared to patients with SF pediatric-onset IBD.

Special Considerations in Pediatric Inflammatory Bowel Disease Pathology

Inflammatory bowel disease (IBD) in the pediatric population presents distinct characteristics compared to adult cases. Pathology plays a critical role in its diagnosis, and this review underscores key considerations in the pathologic evaluation of pediatric IBD. Recognizing inflammatory patterns in the upper gastrointestinal tract can improve disease classification and aid in diagnosing IBD in certain scenarios, such as isolated upper gastrointestinal or small bowel involvement. Additionally, familiarity with distinctive subtypes, including IBD associated with primary sclerosing cholangitis and monogenic forms of IBD, supports early comorbidity detection, enhances patient management, and improves prognostication.

Pediatric Inflammatory Bowel Disease Type Unclassified: A Nationwide Cohort Study in Scotland With up to 20 Years Follow-up Shows Reclassification in the Majority and Mild Course in Those Whose Diagnosis Is Unchanged

BACKGROUND

Given the paucity of long-term longitudinal data for inflammatory bowel disease type unclassified (IBDU), we aimed to clarify IBDU disease course and reclassification rate by presenting nationwide data with up to 20 years of follow-up.

METHODS

We analyzed a prospectively identified 11-year cohort of pediatric patients diagnosed with IBDU between January 1, 2003 and December 31, 2013 at all Scottish pediatric IBD centers and followed up into adult services until December 31, 2022. Data were obtained from electronic medical records at fixed timepoints (5 and 10 years post-diagnosis) and at the final follow-up.

RESULTS

Overall, 102 patients were included in the analysis (57/102 [56%] male, median [interquartile range {IQR}] age at diagnosis: 11.5 [9.1-13.2] years) with a median (IQR) follow-up length of 10.5 (8.6-14.0) years. A change of diagnosis was made in 61 of 102 patients (60%); of these, 30 patients (29%) were reclassified to Crohn's disease (CD) and 31 patients (30%) to ulcerative colitis (UC). Patients who remained with IBDU had higher 1- to 5-year remission rates (IBDU 30/39 [77%] vs reclassified 16/57 [28%], P < .05), with lower rates of moderate-to-severe disease (IBDU 3/39 [8%] vs reclassified 31/57 [54%], P < .05) and less need for biologics across all timepoints (IBDU vs reclassified: first timepoint 1/39 [3%] vs 17/57 [30%], second timepoint 1/33 [3%] vs 26/56 [46%], third timepoint 0/18 [0%] vs 16/33 [49%]; all P < .05). Higher rates of surgical resections were observed in reclassified patients (reclassified 11/61 [18%] vs IBDU 1/41 [2%], P = .02).

CONCLUSIONS

In our nationwide pediatric IBDU cohort, 60% of patients were reclassified to either UC or CD over 10.5 years of median follow-up; those who remained with IBDU had a milder disease course.

Prevalence of Inflammatory Bowel Disease Unclassified, as Estimated Using the Revised Porto Criteria, among Korean Pediatric Patients with Inflammatory Bowel Disease

Purpose

Few studies have reported the prevalence of inflammatory bowel disease unclassified (IBDU) among Korean pediatric IBD (PIBD) population. To address this gap, we used two tertiary centers and nationwide population-based healthcare administrative data to estimate the prevalence of Korean pediatric IBDU at the time of diagnosis.

Methods

We identified 136 patients aged 2-17 years with newly diagnosed IBD (94 Crohn's disease [CD] and 42 ulcerative colitis [UC]) from two tertiary centers in Korea between 2005 and 2017. We reclassified these 136 patients using the revised Porto criteria. To estimate the population-based prevalence, we analyzed Korean administrative healthcare data between 2005 and 2016, which revealed 3,650 IBD patients, including 2,538 CD and 1,112 UC. By extrapolating the reclassified results to a population-based dataset, we estimated the prevalence of PIBD subtypes.

Results

Among the 94 CD, the original diagnosis remained unchanged in 93 (98.9%), while the diagnosis of one (1.1%) patient was changed to IBDU. Among the 42 UC, the original diagnosis remained unchanged in 13 (31.0%), while the diagnoses in 11 (26.2%), 17 (40.5%), and one (2.4%) patient changed to atypical UC, IBDU, and CD, respectively. The estimated prevalences of CD, UC, atypical UC, and IBDU in the Korean population were 69.5%, 9.4%, 8.0%, and 13.1%, respectively.

Conclusion

This study is the first in Korea to estimate the prevalence of pediatric IBDU. This prevalence (13.1%) aligns with findings from Western studies. Large-scale prospective multicenter studies on PIBDU are required to examine the clinical features and outcomes of this condition.

Clinical features of inflammatory bowel disease unclassified: a case-control study

BACKGROUND

Approximately 10-15% of inflammatory bowel disease (IBD) patients with overlapping features of ulcerative colitis (UC) and Crohn's disease (CD) are termed as inflammatory bowel disease unclassified (IBDU). This study aimed to describe the clinical features of IBDU and evaluate the potential associated factors of reclassification.

METHODS

The clinical data of 37 IBDU patients were retrospectively analyzed from November 2012 to November 2020. 74 UC and 74 CD patients were randomly selected and age- and sex-matched with the 37 IBDU patients. Clinical characteristics were compared between the three patient groups. Potential factors associated with the IBDU reclassification were evaluated.

RESULTS

60% of IBDU patients displayed rectal-sparing disease, and 70% of them displayed segmental disease. In comparison to UC and CD, the IBDU group demonstrated higher rates of gastrointestinal bleeding (32.4%), intestinal perforation (13.5%), spontaneous blood on endoscopy (51.4%), and progression (56.8%). The inflammation proceeded relatively slowly, manifesting as chronic alterations like pseudopolyps (78.4%) and haustra blunt or disappearance (56.8%). 60% of IBDU patients exhibited crypt abscess, and 16.7% of them exhibited fissuring ulcers or transmural lymphoid inflammation. The proportions of IBDU patients receiving immunosuppressants, surgery, and infliximab were basically the same as those of CD patients. During the 79 (66, 91) months of follow-up, 24.3% of IBDU patients were reclassified as UC, while 21.6% were reclassified as CD. The presence of intestinal hemorrhaging was associated with CD reclassification, while hypoalbuminemia was associated with UC reclassification.

CONCLUSIONS

IBDU may evolve into UC or CD during follow-up, and hemorrhage was associated with CD reclassification. Different from the other two groups, IBDU exhibited a more acute onset and a gradual progression. When an IBD patient presents with transmural inflammation or crypt abscess but lacks transmural lymphoid aggregates or fissuring ulcers, the diagnosis of IBDU should be considered.

Diagnosis change in pediatric inflammatory bowel disease

OBJECTIVES

This study aims to characterize pediatric inflammatory bowel disease (IBD) patients who change diagnosis and describe the characteristics of that change.

METHODS

A retrospective study was conducted on pediatric IBD patients from the ImproveCareNow (ICN) multicenter international cohort from 2007 to January 2019. Primary outcome was change in diagnosis after the first four visits. Other variables included demographics, diagnostics, disease characteristics, and timing.

RESULTS

6.1% of 18,055 patients aged 1-20 years changed diagnosis. Median time between the baseline visit and first diagnosis change was 0.9 years. Change in diagnosis occurred in 257/12,178 (2.1%) patients with Crohn's disease (CD), 347/4758 (7.3%) patients with ulcerative colitis (UC), and 495/1119 (44.2%) patients with IBD-Unclassified (IBD-U). In multivariable analysis, initial diagnosis of IBD-U and longer follow-up times were associated with greater odds of a diagnosis change.

CONCLUSION

IBD-U initial diagnosis and longer follow-up were associated with increased diagnosis change risk. The most common change was reclassification to CD. Disease activity, moderate malnutrition, and presence of EIMs were not associated with change in diagnosis.

Short noncoding RNAs as predictive biomarkers for the development from inflammatory bowel disease unclassified to Crohn's disease or ulcerative colitis

Numerous pathogenic processes are mediated by short noncoding RNAs (sncRNA). Twenty percent of inflammatory bowel disease (IBD) patients are labelled as IBD unclassified (IBDU) at disease onset. Most IBDU patients are reclassified as Crohn's disease (CD) or ulcerative colitis (UC) within few years. Since the therapeutic methods for CD and UC differ, biomarkers that can forecast the categorization of IBDU into CD or UC are highly desired. Here, we investigated whether sncRNAs can predict CD or UC among IBDU patients. 35 IBDU patients who were initially diagnosed with IBDU were included in this retrospective investigation; of them, 12, 15, and 8 were reclassified into CD (IBDU-CD), UC (IBDU-UC), or remained as IBDU (IBDU-IBDU), respectively. Eight IBD patients, were included as references. SncRNA profiling on RNA from mucosal biopsies were performed using Affymetrix miRNA 4.0 array. Selected probe sets were validated using RT-qPCR. Among all patients and only adults, 306 and 499 probe sets respectively were differentially expressed between IBDU-CD and IBDU-UC. Six of the probe sets were evaluated by RT-qPCR, of which miR-182-5p, miR-451a and ENSG00000239080 (snoU13) together with age and sex resulted in an AUC of 78.6% (95% CI: 60-97) in discriminating IBDU-CD from IBDU-UC. Based on the three sncRNAs profile it is possible to predict if IBDU patients within 3 years will be reclassified as CD or UC. We showed that the expression profile of IBDU patients differ from that of definite CD or UC, suggesting that a subgroup of IBDU patients may compose a third unique IBD subtype.

Fecal Calprotectin in Predicting Relapse of Inflammatory Bowel Disease in Children and Adolescents: A Meta-Analysis and Systematic Review

The application of fecal calprotectin in the relapse of inflammatory bowel disease remains uncertain in children and adolescents. We systematically searched the common databases for eligible studies. Judgment of diagnostic accuracy included pooled sensitivity and specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and pooled area under the receiver operating characteristic curve. Ultimately, a total of 414 participants from six studies were included. The combined sensitivity, specificity, PLR, and NLR with 95% confidence intervals (CIs) were 0.85 (95% CI = 0.65 to 0.79), 0.71 (95% CI = 0.52 to 0.85), 2.95 (95% CI = 1.71 to 5.09), and 0.21 (95% CI = 0.08 to 0.51), respectively. The area under the summary receiver operating characteristic curve was 0.85, and the DOR was 14.14 (95% CI = 4.46 to 44.80). Our study showed that fecal calprotectin as a biomarker to predict the clinical relapse of inflammatory bowel disease during remission in children and adolescents is effective and worth applying. [Pediatr Ann. 2023;52(9):e357-e362.].

Machine Learning in Antibody Diagnostics for Inflammatory Bowel Disease Subtype Classification

Antibody testing in inflammatory bowel disease (IBD) can add to diagnostic accuracy of the main subtypes Crohn's disease (CD) and ulcerative colitis (UC). Whether modern modeling techniques such as supervised and unsupervised machine learning are of value for finer distinction of subtypes such as IBD-unclassified (IBD-U) is not known. We determined the antibody profile of 100 adult IBD patients from the Swiss IBD cohort study with known subtype (50 CD, 50 UC) as well as of 76 IBD-U patients. We included ASCA IgG and IgA, p-ANCA, MPO- and PR3-ANCA, and xANCA measurements for computing different antibody panels as well as machine learning models. The AUC of an optimized antibody panel was 85% (95%CI, 78-92%) to distinguish CD from UC patients. The antibody profile of IBD-U patients was closely related to UC. No specific antibody profile was predictive for IBD-U nor for re-classification. The panel diagnostic was in favor of UC reclassification prediction with a correct assignment rate of 69.2-73.1% depending on the cut-off applied. Supervised machine learning could not distinguish between CD, UC, and IBD-U. More so, unsupervised machine learning suggested only two distinct clusters as a likely number of IBD subtypes. Antibodies in IBD are supportive in confirming clinical determined subtypes CD and UC but have limited capacity to predict IBD-U and reclassification during follow-up. In terms of antibody profiles, IBD-U is not a distinct subtype of IBD.

SYSTEMATIC REVIEW AND META - ANALYSIS OF THE FREQUENCY AND RE-CLASSIFICATION TRENDS OF PEDIATRIC INFLAMMATORY BOWEL DISEASE - UNCLASSIFIED

BACKGROUND

The term inflammatory bowel disease-unclassified (IBDU) is used when an individual has chronic colitis but cannot be sub-typed into ulcerative colitis (UC) or Crohn's disease (CD) on the basis of the clinical, endoscopic, imaging and histopathological features. On follow-up a proportion of patients with IBDU are re-classified as CD or UC. There has been considerable variability in the frequency and reclassification rates of pediatric IBDU in published literature.

METHODS

PubMed and Scopus and were searched for publications related to Pediatric Inflammatory Bowel Disease (PIBD) published between Jan,2014 and July,2021. Two reviewers independently searched and selected studies reporting the frequency of IBDU and/or their re-classification. The pooled prevalence was expressed as proportion and 95%CI. Meta-analysis was performed using the inverse variance heterogeneity model.

RESULTS

A total of 2750 studies were identified through a systematic search of which 27 studies were included in this systematic review. The overall pooled frequency of IBDU (n=16064) was found to be 7.1% (95%CI 5.8-8.5%). There was no variation in IBDU frequency by geographical location. Seven studies (n=5880) were included in the IBDU re-classification analysis. Overall, 50% (95%CI 41-60%) children with IBDU were re-classified on follow-up. Amongst these 32.7% (95% 21-44%) were re-classified to UC and 17% (95%CI 12-22%) were re-classified to CD.

CONCLUSION

IBDU comprises 7.1% of PIBD at initial diagnosis. Half of these children are re-classified into UC or CD on follow-up with a higher likelihood of re-classification to UC as compared to CD.

Histopathological assessment of the microscopic activity in inflammatory bowel diseases: What are we looking for?

Advances in diagnostics of inflammatory bowel diseases (IBD) and improved treatment strategies allowed the establishment of new therapeutic endpoints. Currently, it is desirable not only to cease clinical symptoms, but mainly to achieve endoscopic remission, a macroscopic normalization of the bowel mucosa. However, up to one-third of IBD patients in remission exhibit persisting microscopic activity of the disease. The evidence suggests a better predictive value of histology for the development of clinical complications such as clinical relapse, surgical intervention, need for therapy escalation, or development of colorectal cancer. The proper assessment of microscopic inflammatory activity thus became an important part of the overall histopathological evaluation of colonic biopsies and many histopathological scoring indices have been established. Nonetheless, a majority of them have not been validated and no scoring index became a part of the routine bioptic practice. This review summarizes a predictive value of microscopic disease activity assessment for the subsequent clinical course of IBD, describes the most commonly used scoring indices for Crohn's disease and ulcerative colitis, and comments on current limitations and unresolved issues.

Features and Outcomes of Children with Ulcerative Colitis who Undergo a Diagnostic Change: A Single-Center Experience

PURPOSE

A change in diagnosis from ulcerative colitis (UC) to Crohn's disease (CD) has been reported in pediatric inflammatory bowel disease; however, only a few clinical characteristics and predictors of this diagnostic change have been reported. We aimed to describe the clinical characteristics of patients with UC who underwent a change in diagnosis to CD and identify variables associated with the change.

METHODS

The medical records of pediatric patients with UC who were followed up at the National Center for Child Health and Development between 2006 and 2019 were retrospectively reviewed. Clinical data on disease phenotype, laboratory parameters, endoscopic findings, and treatment of patients whose diagnosis changed to CD (cCD) were compared to those of patients whose diagnosis remained UC (rUC).

RESULTS

Among the 111 patients initially diagnosed with UC, 11 (9.9%) patients were subsequently diagnosed with CD during follow-up. There was no significant difference between the cCD and rUC groups in terms of sex, age at initial diagnosis, and the extent and severity of disease at initial diagnosis. Albumin and hemoglobin levels were significantly lower in the cCD group than in the rUC group. The proportion of patients who required biologics was significantly higher in the cCD group than in the rUC group (p<0.05).

CONCLUSION

Approximately 10% children initially diagnosed with UC were subsequently diagnosed with CD. Hypoalbuminemia and anemia at initial diagnosis and use of biologics could be predictors of this diagnostic change.

Appraisal of the PIBD-classes Criteria: A Multicentre Validation

INTRODUCTION

The PIBD-classes criteria were developed to standardise the classification of children with inflammatory bowel disease [IBD], from Crohn's disease [CD], through IBD-unclassified [IBD-U], to typical ulcerative colitis [UC]. We aimed to further validate the criteria and to explore possible modifications.

METHODS

This was a multicentre retrospective cohort study of children diagnosed with IBD with at least 1 year of follow-up. Clinical, radiological, endoscopic, and histological data were recorded at diagnosis and latest follow-up, as well as the 23 items of the PIBD-classes criteria. The PIBD-classes criteria were assessed for redundant items, and a simplified algorithm was proposed and validated on the original derivation cohort from which the PIBD-classes algorithm was derived.

RESULTS

Of the 184 included children [age at diagnosis 13 ± 3 years, 55% males], 122 [66%] were diagnosed by the physician with CD, 17 [9%] with IBD-U, and 45 [25%] with UC. There was high agreement between physician-assigned and PIBD-classes generated diagnosis for CD [93%; eight patients moved to IBD-U] and for UC [84%; six moved to IBD-U and one to CD]. A simplified version of the algorithm with only 19 items is suggested, with comparable performance to the original algorithm [81% sensitivity and 81% specificity vs 78% and 83% for UC; and 79% and 95% vs 80% and 95% for CD, respectively].

CONCLUSIONS

The PIBD-classes algorithm is a useful tool to facilitate standardised objective classification of IBD subtypes in children. A modified version of the PIBD-classes maintains accuracy of classification with a simplified algorithm.

The use of ICD codes to identify IBD subtypes and phenotypes of the Montreal classification in the Swedish National Patient Register

Introduction: Whether data on International Classification of Diseases (ICD)-codes from the Swedish National Patient Register (NPR) correctly correspond to subtypes of inflammatory bowel disease (IBD) and phenotypes of the Montreal classification scheme among patients with prevalent disease is unknown.Materials and methods: We obtained information on IBD subtypes and phenotypes from the medical records of 1403 patients with known IBD who underwent biological treatment at ten Swedish hospitals and retrieved information on their IBD-associated diagnostic codes from the NPR. We used previously described algorithms to define IBD subtypes and phenotypes. Finally, we compared these register-generated subtypes and phenotypes with the corresponding information from the medical records and calculated positive predictive values (PPV) with 95% confidence intervals.Results: Among patients with clinically confirmed disease and diagnostic listings of IBD in the NPR (N = 1401), the PPV was 97 (96-99)% for Crohn's disease, 98 (97-100)% for ulcerative colitis, and 8 (4-11)% for IBD-unclassified. The overall accuracy for age at diagnosis was 95% (when defined as A1, A2, or A3). Examining the validity of codes representing disease phenotype, the PPV was 36 (32-40)% for colonic Crohn's disease (L2), 61 (56-65)% for non-stricturing/non-penetrating Crohn's disease behaviour (B1) and 83 (78-87)% for perianal disease. Correspondingly, the PPV was 80 (71-89)% for proctitis (E1)/left-sided colitis (E2) in ulcerative colitis.Conclusions: Among people with known IBD, the NPR is a reliable source of data to classify most subtypes of prevalent IBD, even though misclassification commonly occurred in Crohn's disease location and behaviour and also among IBD-unclassified patients.

An Overview of Inflammatory Bowel Disease Unclassified in Children

BACKGROUND

The inflammatory bowel diseases cover a diverse range of conditions generally grouped into Crohn's disease (CD) or ulcerative colitis (UC) based on clinical, laboratory, radiological, endoscopic, and histological criteria. However, inflammatory bowel disease unclassified (IBDU) is used when there are clinical and endoscopic signs of chronic colitis without specific features of UC or CD but features of both. Conjecture exists regarding IBDU, especially in children, as to whether it represents a unique childhood phenotype or whether it reflects the difficulties in assigning an IBD subtype at an early age.

SUMMARY

This review examines the current understanding of pediatric IBDU and assesses the evidence supporting IBDU as a distinctive disease entity on the spectrum of inflammatory bowel disease.

KEY MESSAGES

Pediatric-onset IBDU is more common than adult-onset IBDU. Therefore, an understanding of IBDU in this age group assumes more importance. However, there remains a paucity of information and a lack of exclusive longitudinal studies on pediatric IBDU. Subsequently there is significant disparity in the reported prevalence, clinical course, reclassification trends, and treatment responses around pediatric IBDU. Therefore, it remains challenging to chart the natural history of pediatric IBDU and consequently form an accurate understanding of where pediatric IBDU sits on the spectrum of disease.

Changes in inflammatory bowel disease subtype during follow-up and over time in 44,302 patients

AIM

To investigate inflammatory bowel disease (IBD) register-based subtype classifications over a patient's disease course and over time.

METHODS

We examined International Classification of Diseases coding in patients with ≥2 IBD diagnostic listings in the National Patient Register 2002-2014 (n = 44,302).

RESULTS

18% of the patients changed diagnosis (17% of adults, 29% of children) during a median follow-up of 3.8 years. Of visits with diagnoses of Crohn's disease (CD) or ulcerative colitis (UC), 97% were followed by the same diagnosis, whereas 67% of visits with diagnosis IBD-unclassified (IBD-U) were followed by another IBD-U diagnosis. Patients with any diagnostic change changed mostly once (47%) or twice (31%), 39% from UC to CD, 33% from CD to UC and 30% to or from IBD-U. Using a classification algorithm based on the first two diagnoses ('incident classification'), suited for prospective cohort studies, the proportion adult patients with CD, UC, and IBD-U 2002-2014 were 29%, 62%, and 10% (43%, 45%, and 12% in children). A classification model incorporating additional information from surgeries and giving weight to the last 5 years of visits ('prevalent classification'), suited for description of a study population at end of follow-up, classified 31% of adult cases as CD, 58% as UC and 11% as IBD-U (44%, 38%, and 18% in children).

CONCLUSIONS

IBD subtype changed in 18% during follow-up. The proportion with CD increased and UC decreased from definition at start to end of follow-up. IBD-U was more common in children.