Diagnostic Features of Perianal Fistula in Patients With Crohn's Disease: Analysis of a Japanese Claims Database

Diagnostic Process and Applied Criteria for Crohn's Disease in Patients Presenting with Perianal Lesions in Japan: A Retrospective Observational Multicenter Cohort Study

Introduction

In Japan, the confirmed diagnosis of Crohn's disease (CD) is based on a single, historically established set of clinical criteria. However, for patients who present with a perianal lesion (PL), the diagnostic pattern actually applied is unclear.

Methods

We conducted a retrospective observational multicenter study among patients who presented with a PL without synchronous abdominal symptoms and were subsequently diagnosed with confirmed or probable CD according to the Japanese diagnostic criteria from May 1996 to April 2024. In total, 100 patients with confirmed CD and 10 with probable CD were identified and enrolled.

Results

Among the 100 patients with confirmed CD, 72% met the criterion for the category "confirmed 1: main finding A (longitudinal ulcer) or B (cobblestone appearance)." In the same cohort, 35% met the criterion for the category "confirmed 2: main finding C (non-caseating epithelioid cell granuloma [NCEG]) with secondary finding a (extensive irregular-to-round ulcers or aphthae in the gastrointestinal tract) or b (characteristic anorectal lesions)," including 24% without the main finding A or B. Finally, 4% met the criterion for the category "confirmed 3: all secondary findings a, b, and c (characteristic gastric and duodenal lesions)." All 10 patients with probable CD were diagnosed based on secondary finding b only or secondary findings a and b.

Conclusion

In cases of suspected CD due to initial PLs, histological investigation of NCEG and precise total gastrointestinal inspection should be conducted to confirm the diagnosis.

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.

Evaluation surgical strategies in perianal fistulas treatment: Efficacy draining seton compared to other surgical approaches; a case-control study

Background and Aims

Perianal fistula is a prevalent anorectal condition originating from an infectious crypt extending to the external opening. Multiple surgical methods exist for treating perianal fistulas; however, selecting the appropriate options is still controversial. Our study aims to evaluate seton replacement versus other surgical methods in treating perianal fistula.

Methods

This study recruited 72 patients presenting with perianal discharge and diagnosed with perianal fistula through intra-sphincteric, trans-sphincteric, and supra-sphincteric examinations at Imam Reza and Besat Hospitals from July 2022 up to March 2023. Regarding case-control design, patients were divided into two groups: the first group (n = 36) underwent seton insertion, while the control group (n = 36) received alternative surgical methods. Follow-up was conducted for 1 month post-discharge, with monthly visits for 6 months. Patients were evaluated for fistula tract healing, seton loosening, and daily secretion rate (based on infected pads) during each visit. Finally, the two groups were compared in terms of improvement rates.

Results

In the seton group, approximately 94.4% of patients showed improvement. However, the difference between the groups was insignificant (p = 0.494). Seton replacement was performed in 52% of patients, with the majority requiring replacement twice (61%). Improvement rates were highest among cases with two seton replacements, although the difference was not statistically significant (p = 0.073). Following seton replacement, the most common treatment methods were endoanal flap and fistulotomy, with observed improvement in 10 cases for each procedure.

Conclusion

This study highlights that draining seton remains a primary choice for intermediate treatment due to its satisfactory improvement rate and lower requirement for replacement, especially up to two times.

Darvadstrocel for Complex Perianal Fistulas in Japanese Adults with Crohn's Disease: A Phase 3 Study

BACKGROUND AND AIMS

Previous studies conducted in Europe suggested that darvadstrocel, a suspension of expanded, allogeneic, adipose-derived, mesenchymal stem cells, is safe and effective for treatment-refractory complex perianal fistulas in patients with Crohn's disease. The aim of this study was to evaluate the efficacy and safety of darvadstrocel for the treatment of complex perianal fistulas in Japanese adults with Crohn's disease.

METHODS

This is a phase 3, open-label, single-arm study conducted at nine sites in Japan. Adult patients with non-active or mildly active Crohn's disease and complex perianal fistulas received a single 24-mL intralesional injection of darvadstrocel [120 × 106 cells]. The primary endpoint was combined remission (clinically confirmed closure of all treated external openings that were draining at screening, and absence of collections >2 cm, [confirmed by magnetic resonance imaging] among treated fistulas) at Week 24.

RESULTS

Between March 6, 2019 and February 1, 2021, 22 patients received darvadstrocel and completed the 52-week follow-up. The proportion of patients achieving combined remission at Week 24 was 59.1% (95% confidence interval [CI], 38.5-79.6). The effect was maintained at Week 52, with 68.2% [95% CI, 48.7-87.6] of patients achieving combined remission. Treatment-related adverse events included: one [4.5%] patient with worsening of Crohn's disease and diarrhoea, and one [4.5%] patient with blood bilirubin increase. No new safety findings were identified in this study.

CONCLUSIONS

The efficacy and tolerability of darvadstrocel in Japanese adult patients with treatment-refractory complex perianal fistulas in Crohn's disease were similar to those observed in the previous European study. ClinicalTrials.gov number, NCT03706456.

Crohn's Disease-Associated and Cryptoglandular Fistulas: Differences and Similarities

Perianal fistulas are defined as pathological connections between the anorectal canal and the perianal skin. Most perianal fistulas are cryptoglandular fistulas, which are thought to originate from infected anal glands. The remainder of the fistulas mainly arises as complications of Crohn's disease (CD), trauma, or as a result of malignancies. Fistulas in CD are considered as a consequence of a chronic and transmural inflammatory process in the distal bowel and can, in some cases, even precede the diagnosis of CD. Although both cryptoglandular and CD-associated fistulas might look similar macroscopically, they differ considerably in their complexity, treatment options, and healing rate. Therefore, it is of crucial importance to differentiate between these two types of fistulas. In this review, the differences between CD-associated and cryptoglandular perianal fistulas in epidemiology, pathogenesis, and clinical management are discussed. Finally, a flow chart is provided for physicians to guide them when dealing with patients displaying their first episode of perianal fistulas.