Prior Appendectomy and the Onset and Course of Crohn's Disease in Chinese Patients

The Place of Appendicectomy in Inflammatory Bowel Disease-A Review

The aetiology and pathophysiology of inflammatory bowel disease (IBD) are not completely understood; however, a dysregulated intestinal immune system appears key to its pathogenesis. It has been suggested that the appendix is central to nurturing the enteric mucosal system due to its production of lymphoid products and that an appendicectomy may have an immune modulating effect. The aim of this review is to explore the available evidence for the association between IBD and appendicectomy and attempt to define its impact on the incidence and risk of Crohn's disease (CD) and Ulcerative colitis (UC) onset and progression.

Early Progression Prediction in Korean Crohn's Disease Using a Korean-Specific PrediXcan Model

Crohn's disease (CD) is a chronic inflammatory disorder with potential progression to stricturing (B2) or penetrating (B3) phenotypes, leading to significant complications. Early identification of patients at risk for these complications is critical for personalized management. This study aimed to develop a predictive model using clinical data and a Korean-specific transcriptome-wide association study (TWAS) to forecast early progression in CD patients. A retrospective analysis of 430 Korean CD patients from 15 hospitals was conducted. Genotyping was performed using the Korea Biobank Array, and gene expression predictions were derived from a TWAS model based on terminal ileum data. Logistic regression models incorporating clinical and gene expression data predicted progression to B2 or B3 within 24 months of diagnosis. Among the cohort, 13.9% (60 patients) progressed to B2 and 16.9% (73 patients) to B3. The combined model achieved mean area under the curve (AUC) values of 0.788 for B2 and 0.785 for B3 progression. Key predictive genes for B2 included CCDC154, FAM189A2, and TAS2R19, while PUS7, CCDC146, and MLXIP were linked to B3 progression. This integrative model provides a robust approach for identifying high-risk CD patients, potentially enabling early, targeted interventions to reduce disease progression and associated complications.

Investigating the causal relationship between inflammatory bowel disease and simple appendicitis using Mendelian randomization

The relationship between simple appendicitis and inflammatory bowel disease (IBD) is not clear. In this study, we approach the issue from a genetic perspective, using Mendelian randomization (MR) tools to explore the potential causal connection between the two. We used GWAS data from 12,882 IBD patients (21,770 controls), 5956 crohn's disease (CD) patients (14,927 controls), 6968 ulcerative colitis (UC) patients (20,464 controls), and 4604 simple appendicitis patients (481,880 controls). These statistical data were derived from a large-scale whole-genome association study of individuals with European ancestry. The primary analytical method for inferring the causal relationship between the conditions involved the use of the Inverse Variance Weighting (IVW) method as the main approach for bidirectional MR analysis. The MR analysis results predicted IBD was associated with a lower risk of simple appendicitis (OR: 0.947 (0.911, 0.984), p = 0.005). The results for CD (OR: 0.948 (0.916, 0.981), p = 0.002) and UC (OR: 0.954 (0.917, 0.992), p = 0.020) are consistent with this finding. In the reverse MR analysis, there is no significant association between simple appendicitis and the occurrence of IBD (p > 0.05), and the same holds true for CD and UC (p > 0.05). Our MR study results suggest a potential negative causal effect of IBD on the occurrence of simple appendicitis. Conversely, there does not appear to be a significant causal relationship between simple appendicitis and the risk of developing IBD.

Mucosa-Associated Lymphoid Tissue Surgeries as a Possible Risk for Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Inflammatory bowel disease (IBD) is a group of chronic inflammatory gastrointestinal disorders that are caused by genetic susceptibility and environmental factors and affects a significant portion of the global population. The gut-associated lymphoid tissue (GALT) is known to play a crucial role in immune modulation and maintaining gut microbiota balance. Dysbiosis in the latter has a known link to IBD. Therefore, the increasing prevalence of adenoidectomy in children should be explored for its potential association with IBD. The objective of this paper was to assess the association between adenoid tissue removal and the risk of developing Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

We conducted a pooled meta-analysis to evaluate the extended clinical outcomes in patients who underwent appendicectomy and tonsillectomy compared to those who did not. Our approach involved systematically searching the PubMed database for relevant observational studies written in English. We followed the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines to collect data from various time periods, and to address the diversity in study results; we employed a random-effects analysis that considered heterogeneity. For outcomes, odds ratios (ORs) were pooled using a random-effects model.

RESULTS

Seven studies, out of a total of 114,537, met our inclusion criteria. Our meta-analysis revealed a significant association between appendicectomy and CD (OR: 1.57; 95% confidence interval (CI): 1.01 - 2.43; heterogeneity I2 = 93%). Similarly, we found a significant association between tonsillectomy and CD (OR: 1.93; 95% CI: 0.96 - 3.89; I2 = 62%). However, no significant association was observed between appendicectomy and UC (OR: 0.60; 95% CI: 0.24 - 1.47; I2 = 96%), while a modest association was found between tonsillectomy and UC (OR: 1.24; 95% CI: 1.18 - 1.30; I2 = 0%).

CONCLUSIONS

In summary, we found that the trend of appendicectomy is linked to higher odds of CD, and tonsillectomy is more likely associated with increased odds for both CD and UC, with a risk of bias present.

Ileocecal valve that cannot be intubated in Crohn's disease: is this a sign of poor prognosis?

BACKGROUND

In Crohn's disease (CD), the inability to intubate the ileocecal valve during colonoscopy may be associated with a poor disease prognosis. In this study, we aimed to compare the long-term outcomes of CD patients with and without ileocecal valve intubation during colonoscopy to assess its value as a prognostic parameter.

METHODS

This retrospective study involved CD patients with isolated ileal involvement who underwent colonoscopy between 1993 and 2022. We compared the basic characteristics and long-term clinical outcomes of two groups of patients: those with intubated and non-intubated ileocecal valves during colonoscopy.

RESULTS

Of the 155 participants, 97 (62.5%) patients' ileum could be intubated and 58 (37.5%) could not be intubated. The non-intubated group was younger at diagnosis (39 years versus 30.5 years, p = 0.002), but other baseline characteristics such as sex, smoking status, disease duration, perianal disease, and upper gastrointestinal involvements were similar. The non-intubated group had higher rates of steroid dependence (67.2% versus 46.4%; p = 0.012), biologic treatment (89.7% versus 58.8%; p < 0.001), CD-related hospitalization (81% versus 24.7%; p < 0.001), and major abdominal surgery (58.6% versus 15.5%; p < 0.001). In the logistic regression analysis, the positive predictors of successful ileum intubation were inflammatory type CD (OR: 14.821), high serum albumin level (OR: 5.919), and older age (OR: 1.069), while the negative predictors were stenosing (OR: 0.262) and penetrating (OR: 0.247) CD behavior.

CONCLUSIONS

In Crohn's disease patients with isolated ileal involvement, ileocecal valve cannot be intubated during colonoscopy may indicate the severity of the disease.

Association between prior appendectomy and the risk and course of Crohn's disease: A systematic review and meta-analysis

BACKGROUND AND AIMS

The appendix has an important immune function in both health and disease, and appendectomy may influence microbial ecology and immune function. This meta-analysis aims to assess the association between appendectomy and the risk and course of Crohn's disease (CD).

METHODS

PubMed, EMBASE, and the Cochrane Library were used to identify all studies published until June 2022. Data from studies evaluating the association between appendectomy and CD were reviewed.

RESULTS

A total of 28 studies were included in the final analysis, comprising 22 case-control and 6 cohort studies. A positive relationship between prior appendectomy and the risk of developing CD was observed in both case-control studies (odds ratio [OR]: 1.59, 95% confidence interval [CI]: 1.22-2.08) and cohort studies (relative risk [RR]: 2.28, 95% CI: 1.66-3.14). The elevated risk of CD persisted 5 years post-appendectomy (RR = 1.24, 95% CI: 1.12-1.36). The risk of developing CD was similarly elevated regardless of the presence (RR = 1.64, 95% CI: 1.17-2.31) or absence (RR = 2.77, 95% CI: 1.84-4.16) of appendicitis in patients. Moreover, significant differences were found in the proportion of terminal ileum lesions (OR = 1.63; 95% CI: 1.38-1.93) and colon lesions (OR = 0.70; 95% CI: 0.5-0.84) between CD patients with appendectomy and those without appendectomy.

CONCLUSIONS

The risk of developing CD following an appendectomy is significant and persists 5 years postoperatively. Moreover, the elevated risk of CD may mainly occur in the terminal ileum.

Appendix and Ulcerative Colitis: a Key to Explaining the Pathogenesis and Directing Novel Therapies?

The vermiform appendix is generally considered a redundant organ, but recent evidence suggests that the appendix could contribute to the pathogenesis of inflammatory bowel diseases, in particular ulcerative colitis (UC), and may even have a therapeutic role; however, mechanisms of the appendix involvement remain unclear. Here, we highlight current evidence on the link between the appendix and UC and consider plausible therapeutic implications. A literature search was conducted using PubMed and PubMed Central from inception to Nov 2021 using the terms "Appendix", "UC", "Appendix & UC," "Appendectomy", and "Peri-appendicular patch," including only articles published in English. Reference lists from the selected studies were manually searched and reviewed to gather additional related reports. Inflammation around the appendix ("peri-appendicular patch") has been frequently observed in UC patients without other cecal involvement, and this inflammation can even precede the onset of UC. Epidemiologic studies propose that appendectomy reduces the risk of developing UC or even the risk of flare after UC is diagnosed, although this remains controversial. We reviewed studies showing altered host-microbe interactions in the appendix in UC, which suggest that the appendix could act as a priming site for disease via alterations in the immune response and changes in microbiota carried distally to the colon. In summary, recent literature suggests a possible role for microbes and immune cells within the appendix; however, the role of the appendix in the pathogenesis of UC remains unclear. Further research could clarify the therapeutic potential related to this organ.

Long-term effects of appendectomy in humans: is it the optimal management of appendicitis?

INTRODUCTION

Appendectomy remains the gold standard for treating uncomplicated and complicated appendicitis. However, the vermiform appendix may play a significant role in the immune system (secondary immune function) and maintain a reservoir of the normal microbiome for the human body. The aim of this study was to summarize the long-term effects after appendectomy and discuss whether appendectomy is suitable for all appendicitis patients.

AREAS COVERED

A comprehensive and unbiased literature search was performed in PubMed. The terms 'appendix,' 'appendicitis,' 'appendectomy,' and 'endoscopic retrograde appendicitis therapy' were searched in the title and/or abstract. This review summarizes the long-term effects of appendectomy on some diseases in humans and describes three methods including appendectomy, medical treatment, and an 'organ-sparing' technique, named endoscopic retrograde appendicitis therapy (ERAT) to treat appendicitis.

EXPERT OPINION

Appendectomy remains the first-line therapy for appendicitis. The patient's problem is appendix, not appendicitis. If we treat appendicitis, the problem should be resolved. During COVID-19, an initial antibiotic treatment of mild appendicitis represents a promising strategy. For patients who are worried about the long-term adverse effect after appendectomy and have a strong desire to preserve the appendix and are aware of the risk of appendicitis recurrence, medical treatment, or ERAT could be proposed.