Epidemiology and Natural History of Perianal Crohn's Disease: A Systematic Review and Meta-Analysis of Population-Based Cohorts

Cumulative incidence and prevalence of perianal diseases in patients with inflammatory bowel disease and in the population: a nationwide Swedish study

BACKGROUND

Perianal diseases are more common in patients with Crohn's disease (CD) than in the general population, but data are scarce in other inflammatory bowel disease (IBD) subtypes.

METHOD

Using data from the Swedish National Patient Register (NPR) and SWIBREG, the national quality register for IBD, we estimated the cumulative incidence of perianal fistula/abscess and perianal diseases (fistula, abscess, stenosis, fissure or procedure code for perianal surgery) in relation to diagnosis, and the prevalence in 2023, in individuals with CD, ulcerative colitis (UC) and IBD-unclassified (IBD-U), and in a matched (age, sex, calendar year and region of residence) IBD-free cohort from the general population.

RESULTS

We identified 38,364 patients with incident IBD 2007-2017, and 98,229 patients with prevalent IBD as of 31 December 2022. The cumulative incidence of fistula/abscess was 6.7% at diagnosis, 8.3% at 1 year and 10.4% at 5 years in CD. The corresponding percentages in UC were 0.9%, 1.3% and 2.1%, and in IBD-U 2.4%, 3.1% and 4.5%, respectively. In 2023, 12.8%, 3.1% and 4.1% of patients with prevalent CD, UC and IBD-U had a history of fistula/abscess, compared to 0.8% in the general population. The corresponding numbers for perianal diseases were 19.7%, 7.4%, 8.6% and 2.2%.

CONCLUSIONS

The cumulative incidence and prevalence of perianal diseases in Swedish patients with CD was in parity with reports from other countries, and in patients with UC and IBD-U, it was 3-4 times higher than in the population.

The Impact of Setons on Perianal Fistula Outcomes in Patients With Crohn's Disease Treated With Anti-TNF Therapy: A Multicentre Study

BACKGROUND AND AIMS

We aimed to assess the impact of setons on perianal fistula outcomes in patients with perianal fistulising Crohn's disease (PFCD) treated with anti-TNF therapy.

METHODS

We included patients treated with their first anti-TNF therapy for PFCD after undergoing a pelvic MRI between 2005 and 2022 from 6 North American centres. Our exposure was one or more setons at the time of anti-TNF therapy. Our primary outcome was major adverse fistula outcome (MAFO), a composite of repeat local surgical intervention, hospitalisation, or faecal diversion for PFCD, and our secondary outcome was fistula remission defined clinically. We used 1:1 cardinality matching and propensity score weighting to control for fistula severity based on centrally read MRIs, luminal characteristics, and concomitant therapies.

RESULTS

Our analysis included 221 patients: 81 with setons and 140 without setons. After cardinality matching, our cohorts were balanced (standardised difference < 0.1 for all covariates). Patients with setons had similar rates of MAFO (HR 1.23; 95% CI, 0.68-2.21) and fistula remission at 6 months (OR, 0.81; 95% CI, 0.41-1.59) and 12 months (OR, 0.63; 95% CI, 0.31-1.27) compared to patients without setons. Our results remained stable when analysed by propensity score weighting and in a sensitivity analysis of patients who underwent an exam under anaesthesia. In patients with abscesses, there were lower rates of MAFO (HR, 0.49; 95% CI, 0.19-1.25) but not statistically significant in patients with setons.

CONCLUSIONS

In this multicentre, setons were not associated with improved fistula outcomes. Future prospective controlled studies are warranted.

Adverse maternal outcomes after vaginal versus caesarean delivery in women with Crohn's disease and prior perianal surgery: a population-based study

BACKGROUND AND AIMS

For pregnant women with perianal Crohn's disease (CD), major guidelines recommend delivery by caesarean section (c-section) for active disease, and that delivery mode be governed by obstetric indications for women with inactive disease. However, a significant gray zone exists between active versus inactive disease, such as for women who had a history of prior perianal surgery. We examined adverse maternal outcomes of vaginal delivery versus c-section in women with perianal CD and prior perianal surgeries.

METHODS

We used the Danish national registries to collect information on singleton live births from 1997 through 2022 by mothers with CD and previous perianal surgery. Adverse postpartum maternal outcomes included new perianal or intestinal surgery within 12 months, hospital diagnosed infection or outpatient antibiotic prescription within 6 months, and major haemorrhage within 3 days. Adjusted odds ratios (aOR) were estimated in logistic regression models.

RESULTS

There were 704 deliveries by women with CD and prior perianal surgery, including 245 vaginal deliveries (34.8%) and 459 c-sections (65.2%). Women who delivered vaginally versus by c-section had less new perianal surgery (aOR 0.47, 95% CI, 0.24-0.93) and no significant differences in intestinal CD surgery (aOR 0.87, 95% CI, 0.43-1.75), hospital diagnosed infection (aOR 0.50, 95% CI, 0.18-1.38), outpatient antibiotic prescription (aOR 0.92, 95% CI, 0.65-1.28), or major hemorrhage (aOR 0.79, 95% CI, 0.39-1.59).

CONCLUSIONS

Vaginal delivery was not associated with increased important adverse maternal outcomes in mothers with CD and prior perianal surgery.

Perceptions and emotions in postoperative recovery of patients with perianal diseases

This article examines the complex relationship between disease perception, negative emotions, and their impact on postoperative recovery in patients with perianal diseases. These conditions not only cause physical discomfort, but also carry a significant emotional burden, often exacerbated by social stigma. Psychological factors, including stress, anxiety, and depression, activate neuroendocrine pathways, such as the hypothalamic-pituitary-adrenal axis, disrupting the gut microbiota and leading to dysbiosis. This disruption can delay wound healing, prolong hospital stay, and intensify pain. Drawing on the findings of Hou et al, our article highlights the critical role of illness perception and negative emotions in shaping recovery outcomes. It advocates for a holistic approach that integrates psychological support and gut microbiota modulation, to enhance healing and improve overall patient outcomes.

Development and Validation of a Multimodal Machine Learning Model for Diagnosing and Assessing Risk of Crohn's Disease in Patients With Perianal Fistula

BACKGROUND

Diagnosis of Crohn's disease (CD) can pose challenges, particularly when perianal fistula is the initial presentation.

AIM

To develop and validate a predictive model, establishing a visual web tool for early diagnosis of CD in patients presenting with perianal fistula.

METHODS

This retrospective, multicentre validation study involved patients diagnosed with either perianal fistulising CD or cryptoglandular fistula who underwent initial perianal fistula surgery subsequent to rectal MRI at three Chinese centres from September 2016 to December 2020. A random forest classification model was trained on the derivation cohort (n = 550), randomly split into training and test sets at a 7:3 ratio. Validation utilised data from two external centres (n = 300). Model interpretation employed the Shapley Addictive explanation (SHAP) framework. The validated model was integrated into a web tool for calculating patient-specific risk.

RESULTS

In the derivation cohort, SHAP analysis highlighted rectal wall ulceration, rectal wall thickening, submucosal fistula, and T2 hyperintensity as risk factors, while age was identified as protective. A random forest classification model developed using these top 5 features achieved an AUROC of 0.9425 (95% CI: 0.8943-0.9906). In the validation cohort, the model performed well with AUROC values of 0.9187 (95% CI: 0.8620-0.9754) and 0.9341 (95% CI: 0.8876-0.9806), respectively. We developed a publicly accessible web-based application.

CONCLUSION

We have developed a multimodal machine learning model and a web tool that can predict and present CD risk in patients initially presenting with perianal fistula.

Monitoring-Based Model for Personalizing Fecal Incontinence in Patients With Crohn's Disease: A Multicenter Inception Cohort Study

BACKGROUND AND AIMS

Fecal incontinence (FI) is a common complaint that greatly affects the quality of life of patients with Crohn's disease (CD) and is associated with the clinical characteristics of CD. We aimed to identify risk factors related to FI and construct a risk prediction model for FI in patients with CD.

METHODS

This retrospective study included 600 Chinese patients with CD from 4 IBD centers between June 2016 and October 2021. The patients were assigned to the training (n = 480) and testing cohorts (n = 120). Two nomograms were developed based on the logistic regression and Cox regression models to predict the risk factors for FI in patients with CD. The discriminatory ability and accuracy of the nomograms were evaluated using the receiver operating characteristic (ROC) curves and the area under the ROC curves (AUCs). Additionally, the Kaplan-Meier survival curve was also used further to validate the clinical efficacy of the Cox regression model.

RESULTS

The overall prevalence of FI was 22.3% (n = 134 of 600). In the logistic regression model, age at diagnosis (odds ratio [OR], 1.032; P = .033), penetrating behavior of disease (OR, 3.529; P = .008) and Perianal Disease Activity Index score >4 (OR, 3.068; P < .001) were independent risk factors for FI. In the Cox regression model, age at diagnosis (hazard ratio [HR], 1.027; P = .018), Montreal P classification (HR, 2.608; P = .011), and Perianal Disease Activity Index score >4 (HR, 2.190; P = .001) were independent predictors of the prevalence of FI over time. Two nomograms were developed to facilitate risk score calculation, and they showed good discrimination ability according to AUCs.

CONCLUSIONS

In this study, we identified 4 risk factors related to the prevalence of FI and developed 2 models to effectively predict the risk scores of FI in CD patients, helping to delay the course of FI and improve the prognosis with timely intervention.

Separating Infectious Proctitis from Inflammatory Bowel Disease-A Common Clinical Conundrum

Proctitis refers to inflammation in the rectum and may result in rectal bleeding, discharge, urgency, tenesmus, and lower abdominal pain. It is a common presentation, particularly in genitourinary medicine and gastroenterology, as the two most common causes are sexually transmitted infections and inflammatory bowel disease. The incidence of infective proctitis is rising, particularly amongst high-risk groups, including men who have sex with men, those with HIV seropositive status, and those participating in high-risk sexual behaviours. The most commonly isolated organisms are Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema palladium, herpes simplex virus, and Mycoplasma genitalium. Recently, proctitis was also identified as a common feature during the Mpox outbreak. Distinguishing infective proctitis from inflammatory bowel disease remains a significant clinical challenge as there is significant overlap in the clinical presentation and their endoscopic and histological features. This review compares and highlights the distinguishing hallmarks of both inflammatory and infective causes of proctitis. It provides a practical guide to describe the key features that clinicians should focus on in both clinical and key diagnostic investigations to avoid potential misdiagnosis.

Incidence, disease burden and clinical presentation of patients newly diagnosed with inflammatory bowel disease in a population-based inception cohort

BACKGROUND AND AIMS

Emerging data indicate a stabilizing incidence of inflammatory bowel diseases (IBD), including ulcerative colitis (UC), Crohn's disease (CD), and IBD unclassified (IBDU) in Western countries. We aimed to investigate the incidence of IBD, its initial clinical presentation, and patient-reported burden.

METHODS

Copenhagen IBD Inception Cohort is a prospective, population-based cohort of patients with newly diagnosed IBD according to the ECCO guidelines in the period between May 2021 and May 2023, within a catchment area covering 20% of the Danish population.

RESULTS

Based on 554 patients (UC: 308, CD: 201, and IBDU: 18), the incidence rates per 100,000 person-years were: IBD: 23.4 (95% confidence interval, 21.5-25.4), UC: 14.0 (12.6-15.6), CD: 8.6 (7.4-9.8), and IBDU: 0.8 (0.5-1.3). The median diagnostic delay was significantly shorter for UC (2.5 months (interquartile range [IQR] 1-6)) than for CD (5 months (IQR 1.5-11), p<0.01). Moderate-to-severe disability was reported by 34% of CD patients and 22% of UC patients (p=0.01), severe fatigue by 30% and 26% (p=0.43), and severely impaired health-related quality of life (HRQoL) by 43% and 30% of patients, respectively (p=0.01). Hospitalization rates (UC: 20%, CD: 34%, p<0.01), and need for immunomodulators, biologics, or surgery within three months of diagnosis, were high in both UC (3%, 7%, and 37%, respectively) and CD (31%, 18%, and 10%, respectively).

CONCLUSIONS

We found a high incidence of IBD in Copenhagen with a substantial disease burden characterized by early and high requirement for advanced therapies and high rates of fatigue, disability and impaired HRQoL at diagnosis.

Review article: Measuring disease severity in inflammatory bowel disease - Beyond treat to target

BACKGROUND

Inflammatory bowel disease (IBD) follows a heterogenous disease course and predicting a patient's prognosis is challenging. There is a wide burden of illness in IBD and existing tools measure disease activity at a snapshot in time. Comprehensive assessment of IBD severity should incorporate disease activity, prognosis, and the impacts of disease on a patient. This review investigates the concept of disease severity in adults with IBD to highlight key components contributing to this.

METHODS

To perform this narrative review, a Medline search was conducted for full-text articles available at 1st March 2024 using search terms which encompassed disease activity assessment, disease severity, prognosis, natural history of Crohn's disease (CD) and ulcerative colitis (UC), and the burden of IBD.

RESULTS

Current methods of disease assessment in IBD have evolved from a focus on the burden of symptoms to one that includes inflammatory targets, genetic, serological, and proteomic profiles, and assessments of quality-of-life (QoL), disability, and psychosocial health. Longitudinal studies of IBD suggest that the burden of illness is driven by disease phenotype, clinical markers of complicated disease course (previous intestinal resection, corticosteroid use, perianal disease in CD, recent hospitalisations in UC), gut inflammation, and the impact of IBD on the patient.

CONCLUSIONS

Disease severity in IBD can be difficult to conceptualise due to the multitude of factors that contribute to IBD outcomes. Measurement of IBD severity may better encapsulate the full burden of illness rather than gut inflammation alone at a single timepoint and may be associated with longitudinal outcomes.

Current and emerging therapeutic strategies for perianal fistula in Crohn's disease patients

The long-term remission rates achieved with current treatment options for Crohn's disease with perianal fistula (CD-PAF)-including antibiotics, biologics, immunomodulators, and Janus kinase inhibitors, often combined with advanced surgical interventions-remain unsatisfactory. This chapter explores several innovative biomaterials-based solutions, such as plugs, adhesives, fillers, and stem cell-based therapies. The key approaches and treatment outcomes of these advanced therapies are examined, focusing on their ability to modulate the immune response, promote tissue healing, and improve patient outcomes. Additionally, the chapter discusses future directions, including the optimization of biomaterial designs, enhancement of delivery and retention of regenerative therapies, and a deeper understanding of the underlying mechanisms of healing.

Perianal Crohn's disease: Still more questions than answers

In this editorial we comment on the article by Pacheco et al published in a recent issue of the World Journal of Gastroenterology. We focus specifically on the burden of illness associated with perianal fistulizing Crohn's disease (PFCD) and the diagnostic and therapeutic challenges in the management of this condition. Evolving evidence has shifted the diagnostic framework for PFCD from anatomical classification systems, to one that is more nuanced and patient-focused to drive ongoing decision making. This editorial aims to reflect on these aspects to help clinicians face the challenge of PFCD in day-to-day clinical practice.

PTGER4 signaling regulates class IIa HDAC function and SPINK4 mRNA levels in rectal epithelial cells

BACKGROUND

The prostaglandin receptor PTGER4 facilitates homeostasis in the gut. Previous reports indicate that goblet cells, marked by SPINK4 expression, might be affected by PTGER4 activity. Current evidence suggests that prostaglandin E2 (PGE2) produced by mesenchymal stromal cells (MSC) stimulates PTGER4 in epithelial cells during inflammatory conditions. Here, we investigate the subcellular mechanisms and mRNA levels downstream of PTGER4 activity in epithelial cells.

METHODS

Mucosal cells, organoids, and MSC were obtained from patient biopsies harvested by endoscopy. Using independent and co-cultures, we manipulated the activity of PTGER4, the downstream enzymes, and mRNA levels, by using PGE2, in combination with chemical inhibitors, L-161982, H89, LB100, DAPT, LMK-235, or with butyrate. Immunofluorescence, single cell sequencing, RNAscope, ELISA, real time PCR, and Western blotting were used to examine these samples.

RESULTS

SPINK4 mRNA levels were increased in organoids by co-culture with MSC or exogenous stimulation with PGE2 that could be blocked by L-161982 or LMK-235, PTGER4 or HDAC4 inhibitors, respectively. Expression of PTGER4 was co-localized with JAM-A in the basolateral surfaces in rectal epithelial cells grown as organoids. PGE2 treatment of rectal organoids decreased HDAC4, 5, and 7 phosphorylation levels that could be blocked by L-161982 treatment. Butyrate treatment, or addition of L-161982, increased the phosphorylated levels of HDAC4, 5, and 7.

CONCLUSIONS

These findings suggest a mechanism during mucosal injury whereby MSC production of PGE2 increases HDAC4, 5, and 7 activities in epithelial cells by upregulating PTGER4 signaling, ultimately increasing SPINK4 mRNA levels and extracellular release of SPINK4.

Clinical Course of Isolated Recurrent, Persistent Complex Perianal Fistulas Without Luminal Crohn's Disease: A Multicenter Case Series of 24 Patients

Background

Isolated complex perianal fistulas, without luminal evidence of inflammatory bowel disease in the gastrointestinal tract, pose diagnostic and treatment dilemmas for gastroenterologists and colorectal surgeons. For patients who develop recurrent complex fistulas, a presumptive diagnosis of Crohn's disease may be made. It is unclear whether these cases of isolated perianal disease in the absence of luminal inflammation truly represent isolated severe cryptoglandular fistulas or rather an early presentation of Crohn's disease. We aimed to investigate the clinical course and outcomes of patients with isolated complex perianal fistulas.

Methods

In this retrospective multicenter case series across 6 institutions in the United States, we report the clinical course of patients with isolated recurrent complex perianal fistulas, including their diagnostic evaluation, medical and surgical therapies, and clinical outcomes.

Results

All patients (n = 24) required incision and drainage of perirectal abscesses. The majority received setons (n = 19, 79%), more intensive surgical interventions (n = 15, 62.5%, including fistulotomy/sphincterotomy, advancement flap, and ligation of the intersphincteric fistula tract), antibiotics (n = 17, 71%), and biologic therapy (n = 16, 67%). Nine patients (37.5%) underwent a combined medical-surgical approach with biologics and intensive surgical intervention. Despite surgical and/or medical management, active symptomatic complex perianal fistulas persisted in 58% (n = 14) of patients at follow-up (median 5.5 years, interquartile range 2.5-10 years); symptom remission was achieved in 21% (n = 5), and fistula closure in 21% (n = 5).

Conclusions

These cases highlight a multidisciplinary and multimodal approach when treating isolated complex perianal fistulas and their propensity to persist despite the incorporation of advanced therapies.

Perianal fistulizing lesions of Crohn's disease are associated with long-term behavior and its transition: a Chinese cohort study

BACKGROUND/AIMS

Crohn's disease (CD) has a progressive nature and commonly perianal involvement. The aim of this study is to assess the prevalence, surgical treatment, and outcome of perianal fistulizing CD with associated risk factors in a large Chinese cohort.

METHODS

Hospitalized patients diagnosed with CD in our center were consecutively enrolled between January 2000 and December 2018. Transition of disease behavior was classified according to the presence or absence of penetrating behavior (B3 in the Montreal classification) at diagnosis and at a median follow-up of 102 months.

RESULTS

A total of 504 patients were included, of whom 207 (41.1%) were classified as B3 and 348 (69.0%) as L2/3 at follow-up. Transition of behavior to B3 was observed in 86 patients (17.1%). The incidence of perianal fistulizing lesions was 10.9% at 10 years with a final prevalence of 27.0% (n = 136) at the end of follow-up. Multivariate Cox regression identified independent risks of perianal fistulizing lesions for persistent B3 (hazard ratio, 4.72; 95% confidence interval, 1.91-11.66) and behavior transition of progressed to B3 (hazard ratio, 9.90; 95% confidence interval, 4.60-21.33). Perianal surgical treatments were performed in 104 patients (20.6%). Thirty-six cases (7.1%) were refractory, and it is independently associated with behavior of persistent B3 (P= 0.011).

CONCLUSIONS

Perianal fistulizing lesions occurred frequently in Chinese CD patients. Its incidence and refractory outcome were closely associated with the penetrating CD behavior. An additional risk of perianal fistulizing lesions was indicated for CD patients with behavior of progressing to B3, suggesting further attention.

'My sexual desires, everything, my normal life just stops'; a qualitative study of male sexual health in inflammatory bowel disease

AIM

To describe and interpret the sexual health experiences of men with IBD.

DESIGN

Interpretive qualitative study.

METHODS

In-depth, semi-structured interviews were conducted with 22 men with a diagnosis of Inflammatory Bowel Disease. Interviews were digitally audio-recorded and transcribed verbatim. Data were analysed using constant comparative, thematic analysis.

RESULTS

Three themes were identified from interview data: (1) the disease shapes intimate connections, (2) the disease thwarts sexual experiences and (3) the disease disrupts male gender norms. Men reported that active disease lowered libido and could change pre-, inter- and post-coital sexual practices. All participants noted that health professionals did not initiate the discussion of sexual health and well-being needs in the outpatient hospital setting. Men who engaged in receptive anal sex reported a lack of disease-specific guidance and understanding from professionals.

CONCLUSION

Inflammatory bowel disease can negatively impact the sexual well-being, gender identity and activities of men. Further research is required to identify the care preferences of men with IBD and clarify the barriers and facilitators to sexual health assessment so that nurses may better support the health needs of this population.

IMPLICATIONS FOR THE PROFESSION AND PATIENT CARE

This study highlights the need for sexual health and well-being support that is specific to disease and gender in IBD. There is a paucity of information and guidance for men with peri-anal disease and proctitis who engage in receptive anal sex, which requires urgent attention.

REPORTING METHOD

Reporting follows the COREQ checklist.

PATIENT OR PUBLIC CONTRIBUTION

A patient and public involvement group informed the development of the study design. The group reviewed public facing documents and interview guides. One member of the group provided comments on the identified themes.

Efficacy and Safety of Upadacitinib for Perianal Fistulizing Crohn's Disease: A Post Hoc Analysis of 3 Phase 3 Trials

BACKGROUND & AIMS

Efficacy of upadacitinib, an oral Janus kinase inhibitor, for moderate-to-severe Crohn's disease was demonstrated in phase 3 induction (U-EXCEL, U-EXCEED) and maintenance (U-ENDURE) trials; this post hoc analysis evaluated upadacitinib outcomes in patients with fistulizing disease in these studies.

METHODS

Patients were randomized (2:1) to once daily upadacitinib 45 mg or placebo for 12 weeks. Upadacitinib 45 mg clinical responders were rerandomized (1:1:1) to upadacitinib 15 mg, upadacitinib 30 mg, or placebo for 52 weeks. In patients with fistulas (any and perianal), resolution of drainage, closure of external openings, clinical remission, endoscopic response, and safety were assessed.

RESULTS

Of 1021 patients in U-EXCEL and U-EXCEED, 143 (14.0%) had any fistulas at baseline (66 draining); of these, most (n = 128) had perianal fistulas (56 draining). Greater proportions of patients receiving upadacitinib vs placebo achieved resolution of drainage of perianal fistulas at the end of induction (placebo: 5.6%, n/n = 1/18; upadacitinib 45 mg: 44.7%, n/n = 17/38; P = .003) and maintenance (placebo: 0%, n/n = 0/11; upadacitinib 15 mg: 28.6%, n/n = 4/14; P = .105; upadacitinib 30 mg: 23.1%, n/n = 3/13; P = .223) and closure of perianal fistula external openings (for induction, placebo: 4.8%, n/n = 2/42; upadacitinib 45 mg: 22.1%, n/n = 19/86; P = .013; for maintenance, placebo: 0%, n/n = 0/30; upadacitinib 15 mg: 18.8%, n/n = 6/32; P = .024; upadacitinib 30 mg: 16.0%, n/n = 4/25; P = .037).

CONCLUSION

Patients with fistulizing disease (primarily perianal) treated with upadacitinib achieved higher rates of resolution of drainage, closure of external openings, clinical remission, and endoscopic response vs placebo.

CLINICALTRIALS

gov, Numbers: NCT03345849 (U-EXCEL), NCT03345836 (U-EXCEED), NCT03345823 (U-ENDURE).

Management of Perianal Fistulizing Crohn's Disease

Perianal fistulizing Crohn's disease (CD) represents a severe phenotype of CD that is associated with significant morbidity and reduction in quality of life. Perianal fistulizing CD is caused by a complex interplay of genetic predisposition, immune dysregulation, gut dysbiosis, and various unknown physiological and mechanical factors. A multidisciplinary approach is hence required for optimal management . A detailed anatomical description and classification of perianal fistula, including comprehensive clinical, endoscopic, and radiological diagnostic workup, is an important prerequisite to treatment. For simple perianal fistulas, use of antibiotics and immunomodulators, with or without fistulotomy, are appropriate measures. The medical management of complex perianal fistula, on the other hand, requires adequate control of infection before initiation of therapy with immunomodulators. In active complex perianal fistula, anti-tumor necrosis factors remain the most accepted therapy, with concomitant use of antibiotics or immunomodulators enhancing the efficacy. For patients refractory to anti-tumor necrosis factors, treatment with anti-integrins, anti-interleukins, and small molecules is being evaluated. Mesenchymal stem cells, hyperbaric oxygen therapy, and exclusive enteral nutrition have also been investigated as adjunct therapies. Despite the expansion of the medical armamentarium, a large proportion of the patients require surgical interventions. In this review, we provide an up-to-date overview of the pathophysiology, clinical presentation, diagnosis, and medical management of perianal fistulizing CD. A brief overview of the surgical management of perianal fistulizing CD is also provided.

Does Combined Medical and Surgical Treatment Improve Perianal Fistula Outcomes in Patients With Crohn's Disease? A Systematic Review and Meta-Analysis

BACKGROUND

The optimal treatment of perianal fistulizing Crohn's disease [PFCD] is unknown. We performed a systematic review with meta-analysis to compare combined surgical intervention and anti-tumour necrosis factor [anti-TNF] therapy [combined therapy] vs either therapy alone.

METHODS

MEDLINE, EMBASE, and Cochrane databases were searched systematically up to end December 2023. Surgical intervention was defined as an exam under anaesthesia ± setons. We calculated weighted risk ratios [RRs] with 95% confidence intervals [CIs] for our co-primary outcomes: fistula response and healing, defined clinically as a reduction in fistula drainage or number of draining fistulas and fistula closure respectively.

RESULTS

Thirteen studies were analysed: 515 patients treated with combined therapy, 330 patients with surgical intervention, and 406 patients with anti-TNF therapy with follow-up between 10 weeks and 3 years. Fistula response [RR 1.10; 95% CI 0.93-1.30, p = 0.28] and healing [RR 1.06; 95% CI 0.86-1.31, p = 0.58] was not significantly different when comparing combined therapy with anti-TNF therapy alone. In contrast, combined therapy was associated with significantly higher rates of fistula response [RR 1.25; 95% CI 1.10-1.41, p < 0.001] and healing [RR 1.17; 95% CI 1.00-1.36, p = 0.05] compared with surgical intervention alone. Our results remained stable when limiting to studies that assessed outcomes within 1 year and studies where <10% of patients underwent fistula closure procedures.

CONCLUSION

Combined surgery and anti-TNF therapy was not associated with improved PFCD outcomes compared with anti-TNF therapy alone. Due to an inability to control for confounding and small study sizes, future, controlled trials are warranted to confirm these findings.

Fistulizing Perianal Disease as a First Manifestation of Crohn's Disease: A Systematic Review and Meta-Analysis

Background: Incidences of perianal fistulas (PAFs) as a first manifestation of Crohn's disease (CD) vary widely in the literature. Aim: To analyse the percentage of patients with a PAF preceding CD diagnosis and assess the time to diagnosis. Methods: A systematic literature search was conducted. Studies reporting on patients with a PAF preceding CD diagnosis were identified. Primary outcomes were the (weighted) percentage of patients with CD with a PAF preceding CD and their time to CD diagnosis. Secondary outcomes were the (weighted) percentage of patients with CD with a PAF preceding CD diagnosis in predefined patient subgroups, including (1) sex (men vs. women), (2) ethnicity (Asian vs. non-Asian), and (3) age (paediatric (0-18 y) and patients with elderly onset CD (>60 y) vs. adult patients (18-60 y)). Results: Seventeen studies were included (34,030 patients with CD). In the overall CD population, a PAF preceded CD in 8.6% [95%CI; 5.72; 12.71] with a weighted mean time to CD diagnosis of 45.9 (31.3) months. No studies reported details on sex differences in patients with a PAF as a manifesting sign of CD. In Asian populations, a PAF preceded CD in 17.66% [95%CI; 11.45; 26.25], which was significantly higher when compared with non-Asians (4.99% [95%CI; 3.75; 6.60], OR:3.99, p < 0.0001). In adolescents, an incidence of 9.17% [95%CI; 5.92; 13.93] was found with significantly lower incidences in paediatric patients (6.38% [95%CI; 1.84; 19.85], OR:0.53, p < 0.0001), and elderly-onset patients (3.77% [95%CI; 1.68; 8.25], OR:0.44, p = 0.0035). Conclusions: This systematic review shows that in the literature, almost 10% of patients present with a PAF as a first manifestation of CD, with a mean time to diagnosis of almost four years. These results emphasise that increased clinical awareness is needed.

The Role of Small-Bowel Capsule Endoscopy in the Diagnostic Algorithm of Complicated Perianal Disease

INTRODUCTION

Complicated perianal disease (cPD) may be the sole presentation of Crohn's disease (CD). The role of small-bowel capsule endoscopy (SBCE) in the diagnostic algorithm of cPD is unclear. We aimed to evaluate the role of SBCE as a diagnostic tool, in patients with cPD, after a negative standard workup for CD.

METHODS

A multicenter, retrospective, cross-sectional study, in patients with cPD, and negative standard workup for CD (ileocolonoscopy and cross-sectional imaging), who underwent SBCE for suspected CD. Demographics, biomarkers, and the Lewis Score (LS) were recorded and analyzed. An LS ≥ 135 was considered a positive SBCE for diagnosing CD.

RESULTS

Ninety-one patients were included: 65 (71.4%) males; median age: 37 (29-51) years; cPD duration: 25.1 (12.5-66.1) months. Positive SBCE: 24/91 (26.4%) patients. Fecal calprotectin (FC) positively correlated with LS (r = 0.81; p < 0.001). FC levels of 100 µg/g and 50 µg/g had a sensitivity of only 40% and 55% to rule out small-bowel CD, with a negative predictive value (NPV) of only 76% and 80%, respectively.

CONCLUSIONS

SBCE contributed to CD diagnosis in a quarter of patients with cPD after a negative standard workup. FC levels correlated with the degree of inflammation defined by the LS. However, the NPV of FC was low, suggesting that SBCE should be considered for patients with cPD even after a negative standard workup.

Which magnetic resonance imaging feature is associated with treatment response in perianal fistulizing Crohn's disease?

PURPOSE

Perianal fistulae are disabling complications of Crohn's Disease. Magnetic resonance imaging features could predict treatment response. This study aimed to determine which magnetic resonance imaging features were predictive of long-term clinical outcome in real life.

METHODS

Consecutive patients with magnetic resonance imaging performed in a tertiary center were retrospectively analyzed. Clinical outcome was defined as a need for surgical drainage of perianal fistulae or hospitalization. Clinical data and magnetic resonance imaging features (MAGNIFI-CD and Van Assche indices, degree of fibrosis) were studied.

RESULTS

Fifty-two patients were included between 2016 and 2019 with a mean follow-up of 38 months [29;48]. A higher MAGNIFI-CD index (17/25 versus 11/25; p < 0.01) was associated with an unfavorable long-term clinical outcome. The MAGNIFI-CD index showed an area under the curve of 0.74 (p = 0.006) to predict the clinical outcome of perianal Crohn's disease, compared to 0.67 (p < 0.05) for the Van Assche index. At a threshold of 13 for the MAGNIFI-CD index, sensitivity was 75% (CI95% [59%; 86%]) and specificity was 69% (CI95% [44%; 86%]). No association was found between the degree of fibrosis and clinical outcome, but the association of a high degree of fibrosis (≥ 80%) and of a low MAGNIFI-CD index (≤ 13) was predictive of clinical outcome (p < 0.01).

CONCLUSION

The MAGNIFI-CD index could be used to predict clinical outcome in perianal Crohn's disease. In combination with a high degree of fibrosis, a low MAGNIFI-CD index, may help to identify patients with the best prognosis.

Interventional inflammatory bowel disease: current and future practice

PURPOSE OF REVIEW

Inflammatory bowel diseases (IBD) are associated with several well described neoplastic and structural complications. Increasing disease prevalence, healthcare barriers, and medication refractory phenotypes contribute to ongoing complications despite significant strides in medical management. Enhancements in endoscopic technology and techniques have allowed a minimally invasive approach for what has historically required surgery. In this article, we review the current and future landscape of endoscopic IBD intervention.

RECENT FINDINGS

Endoscopic resection is the first line for managing conventional and complex colitis-associated dysplasia. Evidence supporting endoscopic submucosal dissection is mounting, yet there is a paucity of studies evaluating modified endoscopic mucosal resection techniques or hybrid endoscopic submucosal dissection. We also have more clarity in how best to approach fibrostenotic disease, as we learn how to position endoscopic stricturotomy and stenting, relative to balloon dilation. Finally, applications in managing penetrating and postsurgical complications have been described, but still require further study.

SUMMARY

While important knowledge gaps still exist, the application of endoscopic therapies in IBD is more refined, especially within the management of colitis-associated dysplasia and strictures. The indications for endoscopy in perianal disease and other penetrating manifestations of Crohn's disease presents exciting opportunities for growth.

Scoring Indices for Perianal Fistulising Crohn's Disease: A Systematic Review

BACKGROUND AND AIMS

In this systematic review we summarise existing scoring indices for assessing disease activity and quality of life in perianal fistulising Crohn's disease [PFCD], and highlight gaps in the literature.

METHODS

MEDLINE, EMBASE, and CENTRAL were searched from August 24, 2022, to identify studies evaluating clinical, radiological, or patient-reported outcome measures [PROMS] in PFCD. The primary objective was to identify all available scoring indices and describe the operating properties of these indices.

RESULTS

A total of 53 studies reported on the use of one clinical index [Perianal Disease Activity Index: PDAI], three PROMs, and 10 radiological indices; 25 studies evaluated the operating properties of these indices. The PDAI demonstrated content validity, construct validity, and responsiveness but criterion validity or reliability were not assessed. The Van Assche Index [VAI], modified VAI, and the Magnetic Resonance Index for Assessing Fistulas in Patients with CD [MAGNIFI-CD] were the most studied radiological indices. These indices demonstrated responsiveness and reliability. The VAI and MAGNIFI-CD demonstrated construct validity; criterion and content validity and feasibility have not been assessed. Among the three PROMs, the Crohn's Anal Fistula Quality of Life index demonstrated content and construct validity, inter-observer reliability, and responsiveness; criterion validity, intra-observer reliability, and feasibility have not been assessed for this index.

CONCLUSIONS

There are no fully valid, reliable, and responsive clinical disease or radiological indices for PFCD. Although the radiological indices demonstrated responsiveness and reliability, well-defined cut-offs for response and remission are lacking. Future research should focus on establishing standardised definitions and thresholds for outcomes.

Early diagnosis and treatment of perianal Crohn's disease in a 1-year-old infant: Case report and review of literature

Inflammatory bowel disease is rare in infants and it includes perianal Crohn's disease, which is inflammation at or near the anus. An early diagnosis is essential to prevent the complications that may affect the development and growth of the child.

Challenges in IBD Research 2024: Pragmatic Clinical Research

Pragmatic clinical research is 1 of the 5 focus areas of the Challenges in IBD Research 2024, a multidisciplinary effort by scientists, clinicians, patients, and funders to identify priorities for patient-centric research. This summary provides a comprehensive overview of current gaps in inflammatory bowel disease (IBD) clinical research and actionable approaches to address them. This review is focused on identifying research that is needed to achieve the best outcomes for patients in clinical practice. Research gaps include understanding the needs of understudied patient groups and addressing barriers to care so all patients receive optimal care, validating and using biomarkers to enable early diagnosis and result in better outcomes for adults and children with IBD, and determining the optimal sequencing of treatments (medical, surgical, adjunct) in children and adults. Inclusive pragmatic research is needed to address these gaps and lead to improvements in patient care and outcomes for all populations of patients with IBD.

Development of an MRI-Based Prediction Model for Anti-TNF Treatment Failure in Perianal Crohn's Disease: A Multicenter Study

BACKGROUND & AIMS

Clinical and radiologic variables associated with perianal fistula (PAF) outcomes are poorly understood. We developed prediction models for anti-tumor necrosis factor (TNF) treatment failure in patients with Crohn's disease-related PAF.

METHODS

In a multicenter retrospective study between 2005 and 2022 we included biologic-naive adults (>17 years) who initiated their first anti-TNF therapy for PAF after pelvic magnetic resonance imaging (MRI). Pretreatment MRI studies were prospectively reread centrally by blinded radiologists. We developed and internally validated a prediction model based on clinical and radiologic parameters to predict the likelihood of anti-TNF treatment failure, clinically, at 6 months. We compared our model and a simplified version of MRI parameters alone with existing imaging-based PAF activity indices (MAGNIFI-CD and modified Van Assche MRI scores) by De Long statistical test.

RESULTS

We included 221 patients: 32 ± 14 years, 60% males, 76% complex fistulas; 68% treated with infliximab and 32% treated with adalimumab. Treatment failure occurred in 102 (46%) patients. Our prediction model included age at PAF diagnosis, time to initiate anti-TNF treatment, and smoking and 8 MRI characteristics (supra/extrasphincteric anatomy, fistula length >4.3 cm, primary tracts >1, secondary tracts >1, external openings >1, tract hyperintensity on T1-weighted imaging, horseshoe anatomy, and collections >1.3 cm). Our full and simplified MRI models had fair discriminatory capacity for anti-TNF treatment failure (concordance statistic, 0.67 and 0.65, respectively) and outperformed MAGNIFI-CD (P = .002 and < .0005) and modified Van Assche MRI scores (P < .0001 and < .0001), respectively.

CONCLUSIONS

Our risk prediction models consisting of clinical and/or radiologic variables accurately predict treatment failure in patients with PAF.

Pharmacological Therapies for the Management of Fistulizing Crohn's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Fistulas are a debilitating complication of Crohn's disease [CD]. We conducted a systematic review to assess the efficacy of medical therapies for fistulizing CD.

METHODS

MEDLINE, Embase, and CENTRAL were searched on May 26, 2022, for randomized controlled trials [RCTs] of pharmacological therapy in adults with fistulizing CD. The primary outcome was induction and maintenance of fistula response. Pooled risk ratios [RRs] and 95% confidence intervals [CIs] were calculated. GRADE was used to assess the certainty of evidence.

RESULTS

Thirty-eight RCTs were included. Nineteen trials [50%] exclusively involved perianal fistula. The remaining studies included some participants with non-perianal fistula. Pooled RRs for anti-tumour necrosis factor [TNF] agents were not statistically significant for induction [RR 1.36, 95% CI 0.97-1.91] or maintenance of fistula response [RR 1.48, 95% CI 0.97-2.27]. However, in a sensitivity analysis of studies with fistula response as the primary outcome, anti-TNFs were superior to placebo for induction [RR 1.94, 95% CI 1.10-3.41] and maintenance [RR 1.88, 95% CI 1.23-2.88] of fistula response. Oral small molecules [RR 2.56, 95% CI 1.18-5.53] and mesenchymal stem cell [MSC] therapy [RR 1.26, 95% CI 1.01-1.57] were effective for induction of fistula response. Ustekinumab was associated with maintenance of fistula response [RR 1.80, 95% CI 1.04-3.11]. Vedolizumab was not superior to placebo. The certainty of evidence ranged from very low to moderate.

CONCLUSION

Very low- to moderate-certainty evidence suggests that anti-TNF therapy, oral small molecules, ustekinumab, and MSCs are effective for perianal fistulizing CD. Dedicated fistula studies evaluating biologics and small molecules are needed.

Characteristics, Clinical Outcomes, and Prognosis of Anal and Pouch-related Carcinoma in Patients With Crohn's Disease

BACKGROUND

This study described the clinical characteristics, outcomes, and prognosis of Crohn's disease (CD) patients with anal cancer in a tertiary referral center.

METHODS

The electronic medical records of 35 adult CD patients, including CD of the pouch, with anal carcinoma evaluated at Mayo Clinic Rochester, Florida, or Arizona between January 1989 and August 2022 were retrospectively reviewed.

RESULTS

Before cancer diagnosis, patients with pouch-related carcinoma had a shorter median duration of inflammatory bowel disease than those with anal carcinoma (10 vs 26 years). Twenty-six patients (74%) had perianal diseases or rectovaginal fistula, and 35% had a history of human papillomavirus infection. Twenty-one patients (60%) were diagnosed with cancer by anal examination under anesthesia (EUA). More than half of adenocarcinomas were mucinous. Sixteen patients (47%) were American Joint Committee on Cancer (AJCC) Tumor Nodes Metastasis (TNM) stage 3, and 83% were treated by surgery. At last follow-up, 57% of patients were alive without cancer. The 1-, 3- and 5-year overall survival rates were 93.8% (95% confidence interval [CI], 85.7%-100%), 71.5% (95% CI, 56.4%-90.7%), and 67.7% (95% CI, 51.2%-87.7%), respectively. Advanced AJCC TNM stage (hazard ratio, 3.20 per stage; 95% CI, 1.05-9.72; P = .040) was significantly associated with increased risk of death, whereas the period of cancer diagnosis in 2011-2022 (HR, relative to 1989-2000, 0.16; 95% CI, 0.04-0.72; P = .017) was significantly related to decreased risk of death.

CONCLUSIONS

Anal and pouch-related carcinomas were rare complications of CD, and long-standing perianal diseases were an important risk factor. Anal EUA improved the diagnostic yield. Newer cancer treatment strategies and surgery were associated with excellent survival outcome.

Perianal Fistula; from Etiology to Treatment - A Review

Anal fistula has been a challenging clinical issue for years due to its complex pathogenesis. The risk of frequent recurrence and incontinence complicates long-term treatment. Recent scientific literature has reviewed new techniques used for anal fistula treatment in recent years, assessing the advantages and disadvantages of each based on clinical outcomes. Although surgery is the main method used to treat anal fistula, there is no simple technique that can completely heal complex anal fistula. The surgical treatment should consider the healing outcome and the protection of anal function comprehensively. Several innovative techniques have emerged in recent years, such as combined techniques based on drainage seton and LIFT-plug, which appear to be relatively effective therapies. However, more multi-center prospective trials with long-term follow-up are needed to validate their effectiveness. In some situations, medical treatment may also be considered.

Perianal disease: Updates and controversies in closing the gaps

Perianal complications are common and morbid in children with Crohn's disease. In this review, we describe the epidemiology, the presentation and diagnosis, evaluation and management. We focus on updates such as the increasing frequency of biologic medications and MRI for evaluation. We also highlight controversies on the timing and approaches to surgical techniques. Finally, perianal disease requires the coordination of multidisciplinary care with nursing, radiology, gastroenterology, and surgery to optimize outcomes - both medical and patient-centered.

Perianal Mucinous Adenocarcinoma: A Case of Recurrent Anal Fistula

An anal fistula is a fairly common clinical condition, with a very low incidence of malignant transformation. Mucinous adenocarcinoma is a subtype of adenocarcinoma, and its occurrence within perianal fistula tracts is quite rare. This case report describes a 54-year-old male patient with recurrent anal fistula, initially suspected of Crohn's disease (CD), and ultimately diagnosed with perianal mucinous adenocarcinoma. After our joint internal medicine, surgery, and imaging reassessment, the diagnosis was confirmed. Anal fistula is usually considered a benign lesion, but it may also be associated with other diseases. Due to overlapping symptoms of related diseases, the investigation of malignant lesions is often overlooked. This case report emphasizes the importance of timely referral and multidisciplinary management for disease diagnosis and early treatment.

Crohn's disease

Crohn's disease is a chronic inflammatory disease of the gastrointestinal tract that might lead to progressive bowel damage and disability. The exact cause of Crohn's disease is unknown, but evidence points towards multifactorial events causing dysregulation of the innate immune system in genetically susceptible people. Commonly affecting the terminal ileum and proximal colon, Crohn's disease inflammation is often discontinuous and patchy, segmental, and transmural. Identification of characteristic findings on ileocolonoscopy and histology remains the diagnostic gold standard, but complete assessment involves laboratory abnormalities, including micronutrient deficiencies, cross-sectional imaging to identify transmural disease extent, severity and complications, and a psychosocial assessment. Treatment strategies for patients with Crohn's disease now go beyond achieving clinical remission to include deeper targets of endoscopic healing and consideration of adjunctive histological and transmural targets to alter disease progression potentially further. The use of early effective advanced therapies and development of therapies targeting alternative novel pathways with improved safety profiles have resulted in a new era of healing in Crohn's disease management. Future combination of advanced therapies with diet or other biological drugs and small molecules, together with improvements in tight control monitoring tools and predictive biomarkers might continue to improve outcomes for patients with Crohn's disease.

Editorial: The prevalence and outcomes of perianal Crohn's disease across treatment eras

This article is linked to Gonczi et al papers. To view these articles, visit https://doi.org/10.1111/apt.17836 and https://doi.org/10.1111/apt.17879

Burden of perianal disease in Crohn's disease: Accelerating medical therapy and high rates of perianal surgery over the last four decades - Results from a population-based study over four decades

BACKGROUND

Few population-based studies have investigated the prevalence and disease course of perianal manifestation in Crohn's disease.

AIMS

To analyse the prevalence and outcomes of perianal Crohn's disease including medical therapies and need for perianal surgery, over different therapeutic eras based on the time of diagnosis; cohort A (1977-1995), cohort B (1996-2008), and cohort C (2009-2018) METHODS: Patient inclusion lasted between 1977 and 2018. We followed patients prospectively, and regularly reviewed both in-hospital and outpatient records. We defined a perianal surgical procedure as any perianal incision and excision, fistulotomy, or abscess drainage.

RESULTS

We included 946 incident patients. Perianal disease at diagnosis was present in 17.4% (n = 165) of the total cohort, with a declining prevalence in cohorts A/B/C, respectively (24.7%/18.5%/13.2%; p = 0.001). By the end of follow-up, an additional 9.3% (n = 88) of the total cohort developed perianal disease. Cumulative immunosuppressive and biologic exposure increased over time; biologic use was higher in patients with perianal disease [pLog Rank < 0.001]. The overall rate of perianal surgery was 44.7% (113/253), with a probability of 28.3% (95% CI: 25.4-31.2) after 10 years, 41.0% (95% CI: 37.5-44.5) after 20 years, and 64.1% (95% CI: 59-69.2) after 30 years. There was no statistically significant difference in the probability of first perianal surgery among cohorts A/B/C [Log Rank = 0.594].

CONCLUSIONS

The burden of perianal disease and perianal surgery rates were high in this cohort. Therapeutic strategy was accelerated in patients with perianal Crohn's over time with higher exposure to immunosuppressives and biologics. Surgical management of perianal disease remained unchanged amongst the cohorts.

Perianal fistulizing Crohn's disease: Current perspectives on diagnosis, monitoring and management with a focus on emerging therapies

Crohn's disease (CD), a chronic inflammatory bowel disorder, manifests in various phenotypes, with fistulizing perianal CD (CD-PAF) being one of its most severe phenotypes. Characterized by fistula formation and abscesses, CD-PAF impacts 17% to 34% of all CD cases and with a significantly deleterious impact on patient's quality of life, while increasing the risk for anorectal cancers. The pathogenesis involves a complex interplay of genetic, immunological and environmental factors, with cytokines such as tumor necrosis factor-alpha (TNF-α) and transforming growth factor-beta (TGF-β) playing pivotal roles. Diagnostic protocols require a multi-disciplinary approach including colonoscopy, examination under anesthesia and magnetic resonance imaging. In terms of treatment, biologics alone often prove inadequate, making surgical interventions such as setons and fistula surgeries essential. Emerging therapies such as mesenchymal stem cells are under study. The South Asian context adds layers of complexity, including diagnostic ambiguities related to high tuberculosis prevalence, healthcare access limitations and cultural stigma toward perianal Crohn's disease and ostomy surgery. Effective management necessitates an integrated, multi-disciplinary approach, especially in resource-constrained settings. Despite advances, there remain significant gaps in understanding the disease's pathophysiology and a dearth of standardized outcome measures, underscoring the urgent need for comprehensive research.

Comparative Effectiveness of Biologic Therapies in Preventing Penetrating Complications in Patients With Crohn's Disease

BACKGROUND & AIMS

Comparative effectiveness of biologics in preventing penetrating disease (PD) in Crohn's disease (CD) is not well established. We compared the risk of developing luminal and perianal PD (LPD and PPD) between biologics used as first-line therapies.

METHODS

Adults (>17 years) with CD who initiated their first biologic (anti-tumor necrosis factor [anti-TNF], ustekinumab [UST], or vedolizumab [VDZ]) were identified from Merative Commercial Database (2006 and 2020). We excluded preexisting PD using a minimum look-back period of 1 year. Cohorts were balanced by inverse probability of treatment weighting based on age, sex, comorbidities, prior CD surgery, and CD severity. Pairwise comparisons were performed by Cox proportional hazards models, adjusted for immunomodulator exposure, and with biologic exposure treated as a time-dependent variable based on a medication possession ratio of 0.8.

RESULTS

Our analysis included 40,693 patients: 93% anti-TNF, 3% UST, and 4% VDZ. After inverse probability of treatment weighting all comparisons were well balanced. Anti-TNF was protective against LPD (hazard ratio, 0.66; 95% confidence interval, 0.55-0.78; P < .0001) and PPD (hazard ratio, 0.88; 95% confidence interval, 0.80-0.96; P = .0045) compared with VDZ and LPD (hazard ratio, 0.37; 95% confidence interval, 0.30-0.46; P < .0001) compared with UST. There were no significant differences in the risk of LPD and PPD between VDZ and UST. These results were similar after limiting the study period to after 2016.

CONCLUSIONS

Anti-TNF therapy was associated with a lower risk of LPD and PPD compared with VDZ, and lower risk of LPD compared with UST. Further studies are needed to validate these findings and to determine potential reasons for these differences.

Correlation between Polymorphisms of Vitamin D Metabolism Genes and Perianal Disease in Crohn's Disease

Although the role of vitamin D (VD) in the pathogenesis and progression of Crohn's disease (CD) is known, the association between single-nucleotide polymorphisms (SNPs) of genes linked to vitamin D pathway and CD risk is still under study. Furthermore, no significant association has been previously found between these SNPs and perianal CD (pCD), a severe phenotypic manifestation of CD that may present as perianal fistula, abscess, and recto-vaginal fistula. Among the mechanisms involved in its pathogenesis, local inflammation and intestinal microbiota alteration are recognized. VD seems to act on these elements. The aim of this study was to evaluate the presence of an association between SNPs of genes coding for enzymes, transporters, and receptors involved in the VD pathway and the occurrence of pCD. Blood samples of 206 patients with CD, including 34 with pCD, were analyzed for VDR, CYP27B1, CYP24A1, and GC genetic variants. VDR Apal Aa genotype and VDR BsmI Bb genotype resulted in an association with pCD (p = 0.01 and p = 0.02, respectively). Our study demonstrates for the first time the impact of the polymorphisms of genes associated with the VD pathway on the onset of pCD. Future multicenter studies are needed to confirm these data.

Video Capsule Endoscopy can Identify Occult Luminal Crohn's Disease in Patients with Isolated Perianal Fistulas

BACKGROUND

Accurate tools to distinguish Crohn's disease [CD] from cryptoglandular disease in patients with perianal fistulas without detectable luminal inflammation on ileocolonoscopy and abdominal enterography (isolated perianal fistulas [IPF]) are lacking. We assessed the ability of video capsule endoscopy [VCE] to detect luminal inflammation in patients with IPF.

METHODS

We studied consecutive adults [>17 years] with IPF who were evaluated by VCE after a negative ileocolonoscopy and abdominal enterography between 2013 and 2022. We defined luminal CD by VCE as diffuse erythema, three or more aphthous ulcers, or a Lewis score greater than 135. We compared rates of intestinal inflammation in this cohort with age- and sex-matched controls without perianal fistulas, who underwent VCE for other indications. We excluded persons with pre-existing inflammatory bowel disease [IBD] and exposure to non-steroidal anti-inflammatory drugs or immunosuppressive treatments.

RESULTS

A total of 45 patients with IPF underwent VCE without complications. Twelve patients [26%] met our definition of luminal CD. Luminal CD was more common in patients with IPF than in controls [26% vs 3%; p <0.01]. Among patients with IPF, male sex (OR [odds ratio], 9.2; 95% confidence interval [CI] [1.1-79.4]), smoking (OR, 4.5; 95% CI [0.9-21.2]), abscess (OR, 6.3; 95% CI [1.5-26.8]), rectal enhancement on magnetic resonance imaging [MRI] (OR, 9.0; 95% CI [0.8-99.3]), and positive antimicrobial serology (OR, 7.1; 95% CI, [0.7-70.0]) were more common in those with a positive VCE study.

CONCLUSIONS

VCE detected small intestinal inflammation suggestive of luminal CD in approximately one-quarter of patients with IPF. Larger studies are required to validate these findings.

Typical MR features and interpretation of perianal fistulas in patients with Crohn's disease

Perianal fistulas in Crohn's disease (CD) are a poor prognostic phenotype requiring a combination of medical and surgical management. Perianal fistulas in CD are characterized by more complex and multi-branched fistulas, association with skin tags, and frequent presence of proctitis. A comprehensive approach with clinical examination, endoscopic and MR assessment is required, and in particular, MR interpretation provides detailed information on the type of fistula with its internal component and activity, secondary tracts and extension, internal, external openings, associated abscess, and presence of proctitis. Structured reporting of these items would be recommended for further discussion and management planning both at initial diagnosis and for disease monitoring during treatment follow-up. Management strategy would be individualized for each patient, and control of luminal disease activity could be an important determinant in the selection of treatment options. In this review, we provide an overview of the MRI evaluation of perianal fistulas in CD with a proposed structured MR report.

Management of Perianal Crohn's Disease

Perianal Crohn's disease affects 25%-35% of patients with Crohn's disease and has proven to be one of the most difficult complications of the disease to treat. Patients with perianal Crohn's disease have lower health-related quality of life scores typically related to pain and fecal incontinence. In addition, patients with perianal Crohn's disease have higher rates of hospitalizations, surgeries, and overall healthcare costs. A multidisciplinary approach is necessary for the successful management of Crohn's disease with perianal fistula. Medical management is required to treat the underlying immune dysregulation to heal the luminal inflammation and the inflammation within the fistula tracts. Current options for medical therapy include biologics, dual therapy with thiopurines, therapeutic drug monitoring, and a close follow-up. Surgical management is critical to drain abscesses before immunosuppressive therapy and place setons when appropriate. Once the patient's inflammatory burden is well managed, definitive surgical therapies including fistulotomies, advancement flaps, and ligation of intersphincteric fistula tract procedures can be considered. Most recently, the use of stem cell therapy in the treatment of perianal fistula has given new hope to the cure of perianal fistula in Crohn's disease. This review will outline the most current data in the medical and surgical management of perianal Crohn's disease.

The Intersection of Human and Veterinary Medicine-A Possible Direction towards the Improvement of Cell Therapy Protocols in the Treatment of Perianal Fistulas

The effective treatment of perianal fistulizing Crohn's disease is still a challenge. Local administration of mesenchymal stromal cells (MSCs) is becoming a part of accepted treatment options. However, as a fledgling technique, it still can be optimized. A new trend in translational research, which is in line with "One Health" approach, bases on exploiting parallels between naturally occurring diseases affecting humans and companion animals. Canine anal furunculosis (AF) has been indicated as condition analogous to human perianal Crohn's disease (pCD). This narrative review provides the first comprehensive comparative analysis of these two diseases based on the published data. The paper also outlines the molecular mechanisms of action of MSCs which are likely to have a role in modulating the perianal fistula niche in humans, and refers them to the current knowledge on the immunomodulatory properties of canine MSCs. Generally, the pathogenesis of both diseases shares main determinants such as the presence of genetic predispositions, dysregulation of immune response and the relation to intestine microbiota. However, we also identified many aspects which should be further specified, such as determining the frequency of true fistulas formation in AF patients, elucidating the role of TNF and Th17 pathway in the pathogenesis of AF, or clarifying the role of epithelial-to-mesenchymal transition phenomenon in the formation of canine fistulae. Nevertheless, the available data support the hypothesis that the results from testing cell therapies in dogs with anal furunculosis have a significant translational value in optimizing MSC transplants procedures in pCD patients.

Placebo response rates in randomized controlled trials for perianal Crohn's disease: A systematic review and meta-analysis

BACKGROUND AND AIMS

Perianal fistulizing disease is a common complication of Crohn's disease (CD), for which new therapies are urgently needed. To assist design of clinical trials for novel therapeutics, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to quantify placebo rates and identify factors influencing them in perianal CD.

METHODS

We searched MEDLINE, EMBASE and CENTRAL from inception to June 2021. Eligible studies were placebo-controlled trials of pharmacological interventions for perianal CD (pCD). Placebo fistula response and remission rates for induction and maintenance trials were extracted and pooled using a random-effects model. Mixed-effects meta-regression was used to evaluate the impact of patient and study-level characteristics on point estimates.

RESULTS

In 17 RCTs (13 induction, 5 maintenance) the pooled placebo fistula response and remission rate for induction trials was 25% (95% CI 17-36%) and 17% (95% CI 11-25%), respectively. For maintenance trials, the pooled placebo fistula response and remission rate was 23% (95% CI 17-32%) and 19% (95% CI 14-25%), respectively. Trials enrolling patients with less disease activity and a higher proportion with ileal predominant disease were associated with significantly higher placebo response rates. Trials originating in Europe (compared to North America), therapies requiring perianal injection and a longer timepoint to measure remission were associated with higher placebo remission rates.

CONCLUSIONS

Placebo response and remission rates in pCD trials are influenced by patient and disease-related factors, as well as the type of intervention being studied. These contemporary rates will inform trial design for novel therapeutics.