The prevalence of pouch fistulas in ulcerative colitis following restorative proctocolectomy: a systematic review and meta-analysis.

Background/Aims: One complication of restorative proctocolectomy with ileo-anal pouch anastomosis is fistula formation in the pouch. Fistulas can be associated with significant morbidity and pouch failure. We conducted a systematic review with meta- analysis to try and understand the prevalence of pouch fistulas in patients with ulcerative colitis following restorative proctocolectomy. Methods: The Embase, Embase Classic, and PubMed databases were searched between January 1979 and April 2022. Studies were included if there were cross-sectional, case-controlled, population-based or cohort studies reporting on prevalence of pouch fistulas in ulcerative colitis. Studies had to report the number of patients with pouch fistulas using either clinical, endoscopic, or radiological diagnosis in an adult population. Results: Thirty-three studies screened met the inclusion criteria. The pooled prevalence of developing at least 1 fistula was 0.05 (95% confidence interval [CI], 0.04-0.07). The pooled prevalence of pouch failure in patients with pouch fistula was found to be 0.24 (95% CI, 0.19-0.30). The pooled prevalence of developing a pouch fistula at 3 years, 5 years and more than 5 years was 0.04 (95% CI, 0.02-0.07), 0.05 (95% CI, 0.02-0.07), and 0.05 (95% CI, 0.02-0.10), respectively. Conclusions: This is the first systematic review and meta-analysis to report the prevalence of pouch fistula. It also provides a pooled prevalence of pouch failure in these patients. These results can help to shape future guidelines, power future studies, and help counsel patients.

Treatment Targets Should Influence Choice of Infliximab Dose Intensification Strategy in Inflammatory Bowel Disease: A Pharmacokinetic Simulation Study.

BACKGROUND: The optimal infliximab dose intensification strategy to address loss of response associated with subtherapeutic infliximab trough levels remains uncertain, as does whether post-intensification trough and treatment targets should influence this decision. OBJECTIVES: This pharmacokinetic simulation study aimed to identify infliximab dose intensification strategies capable of achieving post-intensification infliximab trough thresholds associated with clinical and objective treatment targets in Crohn's disease and ulcerative colitis. METHODS: A validated pharmacokinetic infliximab model, applied to 200 simulated patients, identified those with subtherapeutic (< 3.00 mg/L) trough levels after 30 weeks of standard (5 mg/kg 8-weekly) dosing, and subsequently applied 10 dose intensification strategies over a further 32 weeks. The proportion of simulations achieving 32-week post-intensification infliximab trough levels associated with endoscopic remission (ulcerative colitis > 7.50 mg/L, Crohn's disease > 9.70 mg/L) was the primary outcome, with perianal fistula healing (Crohn's disease > 10.10 mg/L) and clinical improvement (ulcerative colitis > 3.70 mg/L, Crohn's disease > 7.00mg/L) evaluated as secondary outcomes. All outcomes were stratified by intensity of dose intensification, with standard (≤ 10 mg/kg 8-weekly or 5 mg/kg 4-weekly; n = 5) and intensive (> 10 mg/kg 8-weekly or 5 mg/kg 4-weekly; n = 5) dosing strategies defined, respectively. RESULTS: The median pre-intensification infliximab trough level was 0.91 mg/L (interquartile range 1.37). Intensive dosing strategies were more likely to achieve infliximab trough concentrations associated with endoscopic remission (ulcerative colitis 36.48% vs. 10.80%, Crohn's disease 25.98 vs. 4.68%), perianal fistula healing (24.52% vs. 4.36%) and clinical improvement (ulcerative colitis 61.90% vs. 34.86%, Crohn's disease 40.32 vs. 12.08%) than standard intensification strategies (all p < 0.01). When controlling for cumulative (mg/kg) infliximab dose over 32 weeks, strategies that concurrently dose increased and interval shortened achieved the highest infliximab trough levels (all p < 0.01). CONCLUSION: This simulation-based analysis highlights the potential of using post-intensification infliximab trough thresholds associated with aspirational treatment targets in Crohn's disease and ulcerative colitis to guide choice of infliximab dose intensification strategy. Intensive dose intensification strategies, particularly those that concurrently dose increase and interval shorten, appear to achieve higher infliximab levels than standard dose intensification strategies. This may be particularly important in the pursuit of stringent endpoints, such as endoscopic remission and fistula healing, which have been consistently associated with higher infliximab trough levels. These findings require validation across real-world cohorts.

Switching from Dose-Intensified intravenous to SubCutaneoUS infliximab in Inflammatory Bowel Disease (DISCUS-IBD): protocol for a multicentre randomised controlled trial.

INTRODUCTION: A substantial proportion of patients with inflammatory bowel disease (IBD) on intravenous infliximab require dose intensification. Accessing additional intravenous infliximab is labour-intensive and expensive, depending on insurance and pharmaceutical reimbursement. Observational data suggest that subcutaneous infliximab may offer a convenient and safe alternative to maintain disease remission in patients requiring dose-intensified infliximab. A prospective, controlled trial is required to confirm that subcutaneous infliximab is as effective as dose-intensified intravenous infliximab, to identify predictors of disease flare and to establish the role of subcutaneous infliximab therapeutic drug monitoring. METHODS AND ANALYSIS: The DISCUS-IBD trial is an investigator-initiated, prospective, multicentre, randomised, open-label non-inferiority study comparing the rate of disease flares in participants randomised to continue dose-intensified intravenous infliximab to those switched to subcutaneous infliximab after 48 weeks. Participants are adult patients with IBD in sustained corticosteroid-free remission on any regimen of dose-intensified infliximab up to a maximum of 10 mg/kg 4-weekly intravenously. Participants allocated to intravenous infliximab will continue infliximab at the same dose-intensified regimen they were receiving at study enrolment. Subcutaneous infliximab dosing will be stratified by prior intravenous infliximab dosing. Clinical (Harvey-Bradshaw Index, partial Mayo score), biochemical (C reactive protein, faecal calprotectin), pharmacokinetic (drug-level±antidrug antibodies) and qualitative data are collected 12-weekly until study conclusion at week 48. 13 sites across Australia will participate in recruitment to reach a calculated sample size of 120 participants. ETHICS AND DISSEMINATION: Multisite ethics approval was obtained from the Health District Human Research Ethics Committee (HREC) at The Alfred Hospital under a National Mutual Acceptance (NMA) agreement (HREC/90559/Alfred-2022; Local Reference: Project 618/22, version 1.6, 2 March 2023). Findings will be reported at national and international gastroenterology meetings and published in peer-reviewed journals. DISCUS-IBD was prospectively registered with the Australian and New Zealand Clinical Trials Registry (ANZCTR) prior to commencing recruitment. TRIAL REGISTRATION NUMBER: ACTRN12622001458729.

The aetiology of pouchitis in patients with inflammatory bowel disease.

Restorative proctocolectomy with ileal pouch-anal anastomosis is a treatment option for patients with refractory ulcerative colitis. Pouchitis is the most common complication, representing a spectrum of diseases ranging from acute antibiotic-responsive type to chronic antibiotic-refractory. Early accurate diagnosis using a combined assessment of symptoms, endoscopy and histology is important for both treatment and prognostication. Most patients respond well to antibiotic therapy; however, management of chronic antibiotic-refractory pouchitis remains a challenge, and treatment options are based on small studies. Pouchitis is thought to be driven by the interaction between genetics, the immune system and the environment but as yet a causal relationship has yet to be identified. Further longitudinal assessment of the pouch integrating new technologies may help us understand the factors driving pouchitis. This review outlines the currently understood risk factors and aetiology of pouchitis.

The use of faecal microbiota transplant as treatment for recurrent or refractory Clostridioides difficile infection and other potential indications: second edition of joint British Society of Gastroenterology (BSG) and Healthcare Infection Society (HIS) guidelines.

The first British Society of Gastroenterology (BSG) and Healthcare Infection Society (HIS)-endorsed faecal microbiota transplant (FMT) guidelines were published in 2018. Over the past 5 years, there has been considerable growth in the evidence base (including publication of outcomes from large national FMT registries), necessitating an updated critical review of the literature and a second edition of the BSG/HIS FMT guidelines. These have been produced in accordance with National Institute for Health and Care Excellence-accredited methodology, thus have particular relevance for UK-based clinicians, but are intended to be of pertinence internationally. This second edition of the guidelines have been divided into recommendations, good practice points and recommendations against certain practices. With respect to FMT for Clostridioides difficile infection (CDI), key focus areas centred around timing of administration, increasing clinical experience of encapsulated FMT preparations and optimising donor screening. The latter topic is of particular relevance given the COVID-19 pandemic, and cases of patient morbidity and mortality resulting from FMT-related pathogen transmission. The guidelines also considered emergent literature on the use of FMT in non-CDI settings (including both gastrointestinal and non-gastrointestinal indications), reviewing relevant randomised controlled trials. Recommendations are provided regarding special areas (including compassionate FMT use), and considerations regarding the evolving landscape of FMT and microbiome therapeutics.

The synergy of dual faecal immunochemical and faecal calprotectin testing for accurate assessment of endoscopic and histological activity in inflammatory bowel disease.

Background: Faecal biomarkers are increasingly utilized for disease assessment in inflammatory bowel disease (IBD). Objectives: To characterize the relative and combined accuracy of faecal calprotectin (FC) and faecal immunochemical testing (FIT) for detecting endoscopic and histologically active disease in Crohn's disease (CD) and ulcerative colitis (UC), subdivided by disease location. Design: A prospective cohort study. Methods: Patients with confirmed IBD undergoing routine ileocolonoscopy for activity assessment were prospectively recruited and performed both FC and FIT ±30 days of ileocolonoscopy. Endoscopic activity was assessed via the simplified endoscopic score for CD, Mayo endoscopic score for UC and histological activity graded as nil/mild/moderate. Receiver-operator curve analyses were utilized to assess the performance of FC and FIT per disease subtype and location. Results: In all, 137 (79 CD, 57 UC) patients were recruited. FC was more sensitive than FIT in detecting active endoscopic (CD: 91% versus 69%, UC: 94% versus 82%) and histological (CD: 86% versus 55%, UC 88% versus 56%) disease. However, FIT was more specific than FC in detecting active endoscopic (CD: 94% versus 56%, UC: 85% versus 69%) and histological (CD: 93% versus 55%, UC: 96% versus 70%) diseases. FIT was more sensitive and specific than FC in detecting active colonic CD (endoscopic activity: 94% versus 93%, histological activity: 92% versus 77%, respectively); however, it was poorly sensitive for active ileal CD (43% versus 89%). Conclusion: FC demonstrated higher sensitivity and FIT higher specificity for active IBD. Hence, dual testing was synergistic, displaying excellent performance characteristics across most IBD locations and subtypes, holding promise for future clinical application. Trial registration: Not applicable.

British Society of Gastroenterology guidelines on the management of functional dyspepsia.

In 2022, the British Society of Gastroenterology released guidelines on the management of functional dyspepsia (FD), providing a long-anticipated evidence-based approach to the diagnosis, classification and management of patients with FD. This review summarises the key recommendations of the recent guidelines on the management of FD.

Assessing quality of magnetic resonance enterography and its impact on disease assessment of ileal Crohn's disease.

BACKGROUND/AIMS: Assessment of quality of magnetic resonance enterography (MRE) in small bowel Crohn's disease (CD) activity evaluation has received little attention. We assessed the impact of bowel distention and motion artifact on MRE activity indices in ileal CD. METHODS: A cohort of patients who underwent contemporaneous MRE and colonoscopy for ileal CD assessment between 2014 and 2021 at 2 centers were audited. An abdominal radiologist blinded to clinical data reviewed each MRE, graded bowel distention and motion artifact upon a pre-specified 3-point scale and calculated the original magnetic resonance index of activity (MaRIA) and simplified MaRIA (sMaRIA), London index and CD MRE index (CDMI). Ileal endoscopic activity was graded via the Simplified Endoscopy Score for CD (SES-CD). The performance of MRE indices in discriminating active disease (SES-CD ≥3) stratified by MRE quality was measured by receiver operator characteristic analyses. RESULTS: One hundred and thirty-seven patients had MRE and colonoscopy within a median of 16 days (range, 0-30 days) with 63 (46%) exhibiting active disease (SES-CD ≥3). Forty-four MREs (32%) were deemed low quality due to motion artifact and/or moderate to poor distention. Low-quality MREs demonstrated reduced discriminative performance between ileal SES-CD ≥3 and MRE indices (MaRIA 0.838 vs. 0.634, sMaRIA 0.834 vs. 0.527, CDMI 0.850 vs. 0.595, London 0.748 vs. 0.511, P<0.05 for all). Individually the presence of any motion artifact markedly impacted the discriminative performance (e.g., sMaRIA area under the curve 0.544 vs. 0.814, P<0.05). CONCLUSIONS: Image quality parameters can significantly impact MRE disease activity interpretation. Quality metrics should be reported, enabling cautious interpretation in lower-quality studies.

Prevalence of Extraintestinal Manifestations in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis.

BACKGROUND: Inflammatory bowel disease (IBD) is a multisystem disease impacting various body systems including musculoskeletal, ocular, skin, hepatobiliary, pulmonary, cardiac, and haematological systems. The extraintestinal manifestations of IBD are frequent, common in both ulcerative colitis (UC) and Crohn's disease (CD), and impact the morbidity and mortality of patients. METHODS: The Embase, Embase classic, and PubMed databases were searched between January 1979 and December 2021. A random effects model was performed to find the pooled prevalence of joint, ocular, and skin extraintestinal manifestations of UC and CD. RESULTS: Fifty-two studies were included that reported on 352 454 patients. The prevalence of at least 1 joint, ocular, or skin extraintestinal manifestation in all IBD, UC, and CD was 24%, 27%, and 35% respectively. The prevalence between UC and CD were similar for pyoderma gangrenosum and axial joint manifestations. Ocular manifestations were found to be more common in CD than in UC. Peripheral joint manifestations and erythema nodosum were found to be more common in CD than UC. DISCUSSION: To our knowledge, this is the first meta-analysis that reports on the prevalence of at least 1 joint, ocular, or skin extraintestinal manifestation in IBD. Our results are largely consistent with figures and statements quoted in the literature. However, our findings are based on significantly larger cohort sizes. Thus, our results have the potential to better power studies and more accurately counsel patients.

The prevalence of joint, ocular, or skin extraintestinal manifestations in IBD, UC, and CD was 24%, 27%, and 35% respectively. Ocular manifestations were more common in CD. Peripheral joint manifestations and erythema nodosum were more common in CD.

Crohn's disease: an update.

Crohn's disease (CD) is a chronic, relapsing and remitting inflammatory bowel disease (IBD) that is increasing in incidence and prevalence globally. Management aims to achieve endoscopic healing, symptom resolution and improvement in quality of life. Therapeutic approaches in CD vary depending on disease phenotype. Thiopurines are important in steroid-sparing maintenance therapy, while anti-tumour necrosis factor agents play a fundamental role, especially in fistulising CD. Suboptimal response to these medications may require escalation to other immunosuppressive and biologic therapies, and surgical intervention is still required in a proportion of patients. Tailoring treatment to target specific patient phenotypes, disease severity and patient wishes is becoming more feasible with the growing array of therapeutic options in CD.

The Impact of Obesity on Inflammatory Bowel Disease.

Obesity is prevalent in the inflammatory bowel disease (IBD) population, particularly in newly developed countries where both IBD and obesity in the general population are on the rise. The role of obesity in the pathogenesis of IBD was entertained but results from available studies are conflicting. It does, however, appear to negatively influence disease course whilst impacting on our medical and surgical therapies. The pro-inflammatory profile of the visceral adipose tissue might play a role in the pathogenesis and course of Crohn's Disease (CD). Interestingly, isolating the mesentery from the surgical anastomosis using a KONO-S technique significantly decreases anastomotic recurrence rate. Anti-obesity therapy is not widely used in IBD but was suggested as an adjunctive therapy in those patients. In this review, we aimed to highlight the epidemiology of obesity in IBD and to describe its influence on disease course and outcomes.

Benefits and Challenges of Treat-to-Target in Inflammatory Bowel Disease.

There is notable disparity between symptomatology and disease activity in a significant proportion of patients with inflammatory bowel disease (IBD), and escalation of treatment based on symptoms alone can fail to significantly alter the course of disease. The STRIDE-II position statement, published in 2021 by the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) initiative of the International Organisation for the Study of IBD (IOIBD) provides the most current recommendations for a treat-to-target (T2T) approach in IBD. Despite the benefits offered by a T2T approach in IBD, there are numerous drawbacks and current limitations to its widespread implementation in real-world clinical practice. Owing to the lack of a standardised definition of MH, outcome data are heterogeneous and limit the comparability of existing data. Further, studies investigating the likelihood of achieving MH with a T2T approach are limited and largely retrospective. Evidence of the real-world feasibility of tight monitoring is currently minimal and demonstrates sub-optimal adherence among patients. Further, the few studies on the acceptability and uptake of a T2T approach in real-world practice demonstrate the need for increased acceptability on both patients' and clinicians' behalf. Real-world applicability is further limited by the need for repeated endoscopic assessments of MH as well as a lack of guidance on how to incorporate the various treatment targets into therapeutic decision-making. We aim to review the benefits and challenges of the T2T approach and to discuss potential solutions to further patient care.

Are We Ready to Reclassify Crohn's Disease Using Molecular Classification?

Crohn's disease (CD) is a type of inflammatory bowel disease. The number of IBD cases worldwide was estimated to be 4.9 million in 2019. CD exhibits heterogeneity in clinical presentation, anatomical involvement, disease behaviour, clinical course and response to treatment. The classical description of CD involves transmural inflammation with skip lesions anywhere along the entire gastrointestinal tract. The complexity and heterogeneity of Crohn's disease is not currently reflected in the conventional classification system. Though the knowledge of Crohn's pathophysiology remains far from understood, the established complex interplay of the omics-genomics, transcriptomics, proteomics, epigenomics, metagenomics, metabolomics, lipidomics and immunophenomics-provides numerous targets for potential molecular markers of disease. Advancing technology has enabled identification of small molecules within these omics, which can be extrapolated to differentiate types of Crohn's disease. The multi-omic future of Crohn's disease is promising, with potential for advancements in understanding of its pathogenesis and implementation of personalised medicine.

Sensitivity and specificity of diagnostic modalities in pouchitis: a systematic review and meta-analysis.

Restorative proctocolectomy (RPC) is the most common surgical procedure to restore gastrointestinal continuity after surgical resection of the colon and rectum. Pouchitis is a common complication with several different modalities that can be used to aid diagnosis. This systematic review and meta-analysis aimed at exploring the sensitivity and specificity these diagnostic modalities. The medical literature was searched using MEDLINE, EMBASE and EMBASE classic and PubMed from 1978 to June 2022. We calculated descriptive statistics using sensitivity, specificity, and false-positive rate of the primary studies and also their positive and negative likelihood ratios, and their diagnostic odds ratios. The screen found 5477 records with 13 studies being included. Faecal lactoferrin was found to have the highest pooled sensitivity and specificity of 98% and 88% respectively with imaging modalities coming in second and faecal calprotectin third with pooled sensitivities and specificities of 87% and 79% and 74% and 81% respectively. Faecal biomarkers particularly lactoferrin and imaging modalities may have an important role to play in diagnosing pouchitis. Importantly due to delays in availability of pouchoscopy, our data supports early ordering of these tests to help delineate from other causes. Further studies are required with larger cohort sizes to further validate these tests.

Factors associated with long-term healthcare expense and steroid exposure in patients admitted with acute severe ulcerative colitis.

Background and Aim: Acute severe ulcerative colitis (ASUC) remains a significant cause of morbidity and healthcare utilization. This study aimed to characterize the total healthcare costs of ASUC, explore factors associated with significant cost over the 12 months following an index admission, and document outcomes including corticosteroid exposure. Methods: Patients admitted from January 2016 until January 2021 for ASUC to a tertiary inflammatory bowel disease (IBD) center in Australia were identified via retrospective chart review. Costs were calculated over a 12-month period following index admission. Results: Seventy-two patients (30 [42%] female, median age 39 [IQR 27-54] years) were included. The median length of stay of index admission was 6 days (IQR 5-10 days). The median cost of index admission was 7829 AUD, which was driven by the initial length of stay (P < 0.01) and requirement for colectomy (P < 0.01). Median total healthcare cost over the first 12 months was 13 873 AUD (IQR 9684-19 936 AUD), again predominately driven by the length of stay (P < 0.01) and requirement for colectomy (P < 0.01). Median cumulative corticosteroid use over 12 months inclusive of index hospitalization was 1760 mg (IQR 1560-2350 mg). Requirement for inpatient medical salvage therapy with infliximab was associated with increased corticosteroid requirement (P = 0.01). Conclusion: Healthcare expense related to ASUC remains high, driven predominantly by the length of stay during initial hospitalization and need for colectomy. From a healthcare cost perspective, novel methods to reduce inpatient hospital stay as well as need for colectomy may help reduce the economic and steroid burden of ASUC.

Prevalence of NUDT15 Genetic Variants and Incidence of Thiopurine-induced Leukopenia in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis.

BACKGROUND AND AIMS: Nudix hydrolase 15 [NUDT15] genetic variants confer an increased risk of thiopurine-induced leukopenia [TIL]; however, their global prevalence in inflammatory bowel disease [IBD] patients is unknown. We aimed to evaluate the global prevalence of NUDT15 variants in IBD patients and incidence of TIL in these patients. METHODS: Six databases were searched from inception until July 2022. Studies reporting the frequency of any NUDT15 variant and/or frequency of leukopenia in adult IBD patients with these variants were included. A random effects model was performed to estimate the pooled prevalence of variants, incidence of early [≤8 weeks] and late [>8 weeks] leukopenia, and relative risk of developing leukopenia. RESULTS: Twenty studies comprising 5232 patients were included. The pooled prevalence of the *1/*3 c.415C > T C/T diplotype was 13% (95% confidence interval [CI]: 10-18%), *3/*3 c.415C > T T/T diplotype was 2% [95% CI: 1-2%], *1/*5 c.52G > A G/A diplotype was 2% [95% CI: 1-3%], and *1/*6 c.36_37insGGAGTC ins/- diplotype was 7% [95% CI: 4-12%]. The pooled prevalence of *1/*3 was high in Japanese [20%, 95% CI: 16-24%] and Chinese patients [18%, 95% CI: 12-27%]. The incidence of early leukopenia was 20% [95% CI: 16-26%] in *1/*3 patients, 99% [95% CI: 7-100%] in *3/*3 patients, and 49% [95% CI: 29-69%] in *1/*6 patients. The incidence of late leukopenia was 36% [95% CI: 26-49%] in *1/*3 patients. CONCLUSIONS: NUDT15 variants are common and strongly predict TIL in IBD patients. Pre-treatment NUDT15 genotyping should be considered particularly in Asian populations, to guide thiopurine dosing and prevent myelotoxicity.