Appendectomy and subsequent risk of inflammatory bowel diseases

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.

Appendectomy and Future Risk of Microscopic Colitis: A Population-Based Case-Control Study in Sweden

BACKGROUND AND AIMS

Microscopic colitis (MC) is an inflammatory bowel disease and a common cause of chronic diarrhea. Appendectomy has been suggested to have immunomodulating effects in the colon, influencing the risk of gastrointestinal disease. The relationship between appendectomy and MC has only been sparsely studied.

METHODS

This was a case-control study based on the nationwide ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) cohort, consisting of histopathological examinations in Sweden, linked to national registers. Patients with MC were matched to population controls by age, sex, calendar year of biopsy, and county of residence. Data on antecedent appendectomy and comorbidities were retrieved from the Patient Register. Unconditional logistic regression models were conducted presenting odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for country of birth and matching factors. Further subanalyses were made based on MC subtypes (lymphocytic colitis and collagenous colitis), follow-up time postappendectomy and severity of appendicitis.

RESULTS

The study included 14,520 cases of MC and 69,491 controls, among these 7.6% (n = 1103) and 5.1% (n = 3510), respectively, had a previous appendectomy ≥1 year prior to MC or matching date. Patients with a previous appendectomy had an increased risk of MC in total (OR, 1.50; 95% CI, 1.40-1.61) and per the collagenous colitis subtype (OR, 1.67; 95% CI, 1.48-1.88) or lymphocytic colitis subtype (OR, 1.42; 95% CI, 1.30-1.55). The risk remained elevated throughout follow-up, and the highest risk was observed in noncomplicated appendicitis.

CONCLUSIONS

This nationwide case-control study found a modestly increased risk of developing MC following appendectomy.

Evolving Experimental Platforms to Evaluate Ulcerative Colitis

Ulcerative colitis (UC) is a multifactorial disease defined by chronic intestinal inflammation with idiopathic origins. It has a predilection to affect the mucosal lining of the large intestines and rectum. Management of UC depends upon numerous factors that include disease pathogenesis and severity that are maintained via medical or surgical means. Chronic inflammation that is left untreated or managed poorly from a clinical stance can result in intestinal ulceration accompanied by resulting physiological dysfunction. End-stage UC is mediated by surgical intervention with the resection of diseased tissue. This can lead to numerous health-related quality of life issues but is considered a curative approach. Regimens to treat UC are ever evolving and find their basis within various platforms to evaluate and treat UC. Numerous modeling systems have been examined to delineate potential mechanisms of action. However, UC is a heterogenous disease spanning unknown genetic origins coupled with environmental factors that can influence disease outcomes and related treatment procedures. Unfortunately, there is no one-size-fits-all model to fully assess all facets of UC. Within the context of this review article, the utility of various approaches that have been employed to gain insight into different aspects of UC will be investigated.

Appendectomy and risk for inflammatory bowel disease: effect of age and time post appendectomy - a cohort study

Background and objective

Appendectomy may modulate the risk of inflammatory bowel disease through an effect on the gut microbiota. This study investigated the associations between appendectomy and incidence of Crohn’s disease (CD) or ulcerative colitis (UC), with an emphasis on the influence of age and time post appendectomy.

Methods

This cohort study included 400 520 subjects born in Québec in 1970–1974 and followed until 2014. Administrative health data were used to ascertain appendectomy and cases of CD and UC. Cox proportional hazards models with time-dependent variables (appendectomy and time elapsed post appendectomy) allowed for the estimation of HRs and 95% CIs.

Results

A total of 2545 (0.6%) CD cases and 1134 (0.3%) UC cases were identified during follow-up. Appendectomy increased the risk of CD (HR=2.02; 95% CI: 1.66 to 2.44), especially when performed at 18–29 years of age. The risk of CD was increased in the first 2 years, and decreased significantly after ≥15 years post appendectomy. Appendectomy appeared to protect against UC (HR=0.39; 95% CI: 0.22 to 0.71). The risk of UC was not associated with age at appendectomy, but decreased with time elapsed post appendectomy (HR=0.21; 95% CI: 0.06 to 0.72, comparing ≥5 with 0–4 years after appendectomy).

Conclusions

The increased risk of CD related to appendectomy in young adults may result from detection bias, but physicians should have a low threshold for suspicion of CD in young symptomatic adults with a history of appendectomy. A strong protective effect of appendectomy against UC was observed after 5 years.

Systematic review with meta-analysis: environmental and dietary differences of inflammatory bowel disease in Eastern and Western populations

BACKGROUND

While the incidence of inflammatory bowel disease (IBD) has stabilised in the West, it is still increasing in several newly industrialised countries.

AIMS

To investigate whether the environmental and dietary risk factors for IBD differ between Eastern and Western populations METHODS: We systematically searched PubMed, Embase, and Web of Science for studies published from inception through June 30, 2020. Data were pooled using a random effects model.

RESULTS

Overall, 255 studies were assessed. We identified 25 risk factors for IBD, seven of which were noted in both Eastern and Western populations: family history of Crohn's disease [CD] or ulcerative colitis [UC], former smoking (CD/UC), smoking (CD), appendicectomy (CD), tonsillectomy (CD), meat and meat products (CD), and vitamin D deficiency (UC). The remaining factors, including urban living, current smoking, antibiotics, oral contraceptives, caesarean section, isotretinoin, total energy, fat, cholesterol, fatty acids and their sub-classifications, eggs, and soft drinks, were associated with an increased risk of IBD in Western or Eastern populations only. We identified 21 protective factors for IBD, among which eight were common in the East and West: farm animals (CD/UC), Helicobacter pylori infection (CD/UC), multiple births (CD), physical activity (CD), history of breastfeeding (CD), pets (UC), current smoking (UC), and coffee intake (UC). Ten factors conferred protection against IBD in Western populations only, whereas eight factors conferred protection against IBD in Eastern populations only.

CONCLUSIONS

Numerous environmental and dietary factors influenced the development of IBD in both Western and Eastern populations, whereas certain factors influenced IBD risk differently in these populations.

Changes in disease behaviour and location and factor analysis in patients with Crohn's disease undergoing repeated-resections

AIM

Crohn's disease affects the entire gastrointestinal tract and is accompanied by changes in disease location and behaviour. We aimed to analyse changes and the factors in patients with Crohn's disease undergoing intestinal repeated-resection.

METHODS

We included and retrospectively analyzed patients with Crohn's disease who received ≥2 bowel surgeries from a tertiary inflammatory bowel disease centre from January 2008 to December 2019. The Montreal classification was used to describe the disease site and behaviour. Factors were assessed by univariate and multivariate analysis.

RESULTS

A total of 339 patients were included of whom 94 patients received ≥3 bowel resections. The median patient's age at the second and third surgery was 36.4 and 39.6, respectively. Repeated-resection most commonly occurred in the original surgical site. However, disease behaviour progressed with the number of surgical interventions and disease duration, especially for patients with B1 phenotype. Patients with L1 Crohn's disease at a primary resection that progressed to L2 Crohn's disease at a second surgical resection required a resection earlier than patients whose disease remained in L1 or progressed to L3 Crohn's disease. Multivariate analysis showed that history of appendectomy was a predictor of progression from L1 to L3 Crohn's disease at a second surgical resection, while treatment with azathioprine (AZA) may be a protective factor that abated the risk of progression from L1 to L3 Crohn's disease.

CONCLUSION

The original resection site is the most common location for recurrence in patients with Crohn's disease, but disease behaviour progresses with the number of surgeries and disease duration. L1 Crohn's disease patients with a history of appendectomy have a higher risk to progress to L3 Crohn's disease at a second surgical resection, while the AZA may be a protective factor that reduces the risk of progression from L1 to L3.

Risk of Inflammatory Bowel Disease Following Appendectomy in Adulthood

Background: The appendix has a complicated immune function, and appendectomy may derange the immune system. Studies on the relationship between appendectomy and subsequent inflammatory bowel disease (IBD) have been inconsistent. We conducted a nationwide cohort study consisting of individuals who underwent appendectomy to evaluate the incidence and risk of ulcerative colitis (UC) and Crohn's disease (CD).

Methods: We identified patients aged >20 years who underwent appendectomy between 2000 and 2012 from inpatient claims of the National Health Insurance Research Database (NHIRD) and assigned them to the appendectomy cohort. Then, we randomly selected patients without appendectomy in the NHIRD and assigned them to the comparison cohort in a frequency-matched 1:1 ratio based on sex, age, and index year. We tracked down all participants until IBD diagnosis, death, or the end of 2013. Cox models were used to estimate the hazard ratio (HR), and 95% confidence intervals (CIs) were used to compare the IBD risk between the appendectomy and comparison cohorts.

Results: The appendectomy and comparison cohorts in the study consisted of 246 562 patients each. The appendectomy cohort exhibited a 2.23- and 3.48-fold higher risk of UC (adjusted HR = 2.23, 95% CI = 1.59-3.12) and CD (adjusted HR = 3.48, 95% CI = 2.42-4.99), respectively, than did the comparison cohort. UC and CD risks significantly increased in the appendectomy cohort regardless of whether appendicitis was present.

Conclusions: Our study suggests that appendectomy increases UC and CD risks irrespective of appendicitis.

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.

Identification of Environmental Risk Factors Associated With the Development of Inflammatory Bowel Disease

BACKGROUND AND AIMS

Multiple genetic and environmental factors are involved in the aetiology of inflammatory bowel disease [IBD] including Crohn's disease [CD] and ulcerative colitis [UC], but data on these exposome factors are difficult to identify. Several exposome factors such as smoking have been shown to be involved; as for other environmental factors, eg stress, results have been conflicting.

METHODS

We performed a case-control study including 674 IBD patients of the 1000IBD cohort, frequency-matched based on sex and age with 1348 controls from the population-based Lifelines Cohort Study. Exposome data were obtained using the validated Groningen IBD Environmental Questionnaire [GIEQ], capturing exposome factors through different stages of life using 844 items, of which 454 were applicable to study the role of 93 exposome factors in disease aetiology. Logistic regression [LR] modelling with Bonferroni correction for multiple testing was applied to estimate the multivariable-adjusted effect of each exposome factor.

RESULTS

For IBD, we identified four novel factors: stressful life events (CD odds ratio [OR] 2.61/UC OR 2.92), high perceived stress [2.29/2.67], alcohol use [0.40/0.43], and bronchial hyper-reactivity [3.04/2.36]. Four novel factors were associated with only CD: prenatal smoke exposure [1.89], having a bed partner [0.53], allergies [2.66], and cow's milk hypersensitivity [5.87]; and two solely with UC: carpet flooring [0.57] and neuroticism [1.32]. Nine factors were replicated.

CONCLUSIONS

In this study we identified 10 novel, and replicated nine previously reported, exposome factors associated with IBD. Identifying these factors is important for both understanding disease aetiology and future prevention strategies to decrease the development of IBD in genetically susceptible persons.

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

Background and Aim

The relationship between prior appendectomy and Crohn's disease (CD) has previously revealed conflicting findings. The present study investigates the relationship between prior appendectomy and CD development in Chinese patients.

Methods

A retrospective case-control study was performed to compare prior appendectomy rate between CD patients and age- and gender-matched controls at two Chinese hospitals. The clinical course of CD was determined in patients who underwent and did not undergo appendectomies before CD diagnosis.

Results

A total of 617 CD patients and 617 controls were included. The appendectomy rate before CD diagnosis in patients was higher, when compared to controls (6.65% versus 3.73%, P = 0.033). Appendectomy was a risk factor for the onset of CD independent of smoking in the multivariate analysis (OR: 1.878; 95% CI: 1.111–3.174; P = 0.019). Appendectomies were performed closer to the date of CD diagnosis in the trend test (P = 0.039). The rate of appendectomy within one year or 1-5 years before CD diagnosis was higher in patients when compared to that in controls (0.97% versus 0%, P = 0.031; 1.13% versus 0.32%, P = 0.180). However, the rate of appendectomy over five years before CD diagnosis was close to controls (4.54% versus 3.40%, P = 0.392). No significant differences in disease location, behavior, medication, and intestinal resection between appendectomy and nonappendectomy CD patients were found, even in the subgroup analysis by age of appendectomy.

Conclusion

Prior appendectomy is a risk factor for the onset of CD. However, the appendectomy rate only increased for a short duration before CD diagnosis, likely reflecting a diagnostic bias. Prior appendectomy did not influence the features or course of CD.

Effects of Appendectomy on the Onset and Course of Ulcerative Colitis in Chinese Patients

Background

Previous epidemiological studies have suggested that appendectomy may be a protective factor against the development of ulcerative colitis (UC). However, the results of these studies were inconsistent, with rare studies in Chinese populations.

Aim

This study examined the associations between appendectomy performed before UC diagnosis and the occurrence and clinical course of UC in Chinese patients.

Methods

A case control study was conducted to compare the rate of appendectomy between UC patients and controls matched for age and sex at two Chinese hospitals. Clinical course of UC was compared between UC patients who underwent appendectomies before UC diagnosis and who did not.

Results

402 UC patients and 402 controls were included. The percentage of appendectomy performed before UC diagnosis in UC patients did not differ significantly from controls (2.74% vs 3.98%, P = 0.442). Subgroup analysis on the basis of localization of UC patients did not find significant difference from controls. The extent of disease involvement in UC patients who underwent appendectomy was smaller than patients who did not (P = 0.009). Appendectomy was found to be significantly related to the location of the disease independent of smoking status in multivariate analysis (P < 0.001). Appendectomy did not influence severity of disease and need for immunosuppressive treatment or colectomy.

Conclusion

We did not find a significant negative association between appendectomy and the UC occurrence in Chinese patients. Appendectomy performed before UC diagnosis may reduce the extent of UC involvement.

Long-Term Complications of Appendectomy: A Systematic Review

BACKGROUND AND AIMS

Appendectomy is a common surgical procedure, but no overview of the long-term consequences exists. Our aim was to systematically review the long-term complications of appendectomy for acute appendicitis.

MATERIALS AND METHODS

This systematic review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A protocol was registered on PROSPERO (CRD42017064662). The databases PubMed and EMBASE were searched for original reports on appendectomy with n ≥ 500 and follow-up >30 days. The surgical outcomes were ileus and incisional hernia; other outcomes were inflammatory bowel disease, cancer, fertility, and mortality.

RESULTS

We included 37 studies. The pooled estimate of the ileus prevalence was 1.0% over a follow-up period of 4.6 (range, 0.5-15) years. Regarding incisional hernia, we found a pooled estimate of 0.7% prevalence within a follow-up period of 6.5 (range, 1.9-10) years. Ulcerative colitis had a pooled estimate of 0.15% prevalence in the appendectomy group and 0.19% in controls. The opposite pattern was found regarding Crohn's disease with a pooled estimate of 0.20% prevalence in the appendectomy group and 0.12% in controls. No clear pattern was found regarding most of the examined cancers in appendectomy groups compared with background populations. Pregnancy rates increased after appendicitis compared with controls in most studies. Mortality was low after appendectomy.

CONCLUSION

Appendectomy had a low prevalence of long-term surgical complications. We did not find any significant other long-term complications, though the prevalence of Crohn's disease was higher and the prevalence of ulcerative colitis was lower after appendectomy than in controls. Appendectomy did not impair fertility.

Tonsillectomy and inflammatory bowel disease: a meta-analysis

AIM

The pathogenesis of inflammatory bowel diseases remains unclear. Genetic and environmental factors are involved. Studies of the association between tonsillectomy and inflammatory bowel disease have yielded conflicting results.

METHOD

PubMed and EMBASE were searched to identify studies evaluating the association between tonsillectomy and inflammatory bowel disease [Crohn's disease (CD) and ulcerative colitis (UC)]. Odds ratios with 95% CI were calculated using a random- or fixed-effects model. The χ(2) test and I(2) test were used to assess homogeneity. Egger's test was used to evaluate publication bias.

RESULTS

Thirteen observational case-control studies including 4122 patients (3035 UC/1087 CD) and 5103 controls were analysed. The summary odds ratio estimated for UC following a tonsillectomy was 0.932, 95% CI 0.819-1.062. The odds ratio for CD following a tonsillectomy was 1.194, 95% CI 0.992-1.437. Publication bias was not detected (Egger's test coefficient -3.50 to 1.55; P = 0.39).

CONCLUSION

No obvious association between tonsillectomy and inflammatory bowel disease was identified in our meta-analysis.

Determinants of Weight Loss prior to Diagnosis in Inflammatory Bowel Disease: A Retrospective Observational Study

Aims. To identify prevalence, severity, and environmental determinants of weight loss in inflammatory bowel disease (IBD) patients just prior to time of formal diagnosis. Methodology. IBD patients attending outpatient clinic were questioned about weight loss prior to diagnosis and other environmental and demographic variables. The percentage BMI loss was calculated for each subject and factors associated with weight loss were determined. Results. Four hundred and ninety-four subjects were recruited (237 cases of Crohn's disease (CD) and 257 cases of ulcerative colitis (UC)). Overall, 57% of subjects with CD and 51% of subjects with UC experienced significant weight loss prior to diagnosis (>5% BMI loss). Younger age at diagnosis and history of previous IBD surgery were significantly associated with both lower BMI at diagnosis and increased weight loss prior to diagnosis. In CD patients, increasing age at diagnosis was inversely associated with weight loss prior to diagnosis. Ileal disease was a risk factor of weight loss, whereas prior appendectomy was associated with reduced risk of weight loss. Conclusions. Weight loss is a significant problem for many IBD patients at presentation, especially in younger age and CD with ileal involvement. Appendectomy is associated with diminished weight loss.

Epidemiological studies of migration and environmental risk factors in the inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are idiopathic chronic diseases of the gastrointestinal tract well known to be associated with both genetic and environmental risk factors. Permissive genotypes may manifest into clinical phenotypes under certain environmental influences and these may be best studied from migratory studies. Exploring differences between first and second generation migrants may further highlight the contribution of environmental factors towards the development of IBD. There are few opportunities that have been offered so far. We aim to review the available migration studies on IBD, evaluate the known environmental factors associated with IBD, and explore modern migration patterns to identify new opportunities and candidate migrant groups in IBD migration research.

Pre-colectomy appendectomy and risk for Crohn's disease in patients with ileal pouch-anal anastomosis

BACKGROUND

A subset of patients with a pre-operative diagnosis of ulcerative colitis can develop Crohn's disease (CD) of the pouch after restorative proctocolectomy. While appendectomy has been implicated to be associated with an increased risk for CD, its impact on the development of de novo CD of the pouch in patients' ileal pouch-anal anastomosis (IPAA) has not been studied. The aims of the study were to assess the prevalence of CD of the pouch in patients with pre-colectomy appendectomy and to investigate the impact of appendectomy on the development of de novo CD of the pouch.

METHODS

All eligible patients with restorative proctocolectomy and IPAA for IBD who had available information on pre-colectomy appendectomy were studied. Demographic and clinical characteristics were evaluated. Cox regression analysis was performed.

RESULTS

The study included 434 patients (44.9 % male) with a mean age of 45.2 ± 4.4 years and follow-up of 4.6 ± 2.3 years. Forty patients (9.2 %) had had appendectomy prior to colectomy. Appendectomy was not shown to be associated with CD of the pouch or its phenotypes in both univariable and multivariable analyses. In the Cox model, independent risk factors associated with CD of the pouch were active smoking (hazard ratio [HR] =1.58; 95 % confidence interval [CI], 1.03-2.43) and family history of CD (HR=1.82; 95 % CI, 0.99-3.32).

CONCLUSIONS

While this study has shown no association between previous appendectomy and the development of CD of pouch, active smoking was an independent risk factor for development of CD of the pouch.

Environmental factors in inflammatory bowel disease: a case-control study based on a Danish inception cohort

BACKGROUND

The role of environmental factors in development of inflammatory bowel disease (IBD) remains uncertain. The aim of the present study was to assess a number of formerly suggested environmental factors in a case-control study of an unselected and recently diagnosed group of patients with IBD and a control group of orthopaedic patients.

METHODS

A total of 123 patients diagnosed with Crohn's disease (CD) and 144 with ulcerative colitis (UC) in Copenhagen (2003-2004) were matched 1:1 on age and gender to 267 orthopaedic controls. Participants received a questionnaire with 87 questions concerning environmental factors prior to IBD/orthopaedic admission. Odds ratios (OR) were calculated by logistic regression.

RESULTS

Being breastfed >6 months (OR, 0.50; 95% CI, 0.23-1.11) and undergoing tonsillectomy (OR, 0.49; 95% CI, 0.31-0.78) decreased the odds for IBD, whereas appendectomy decreased the odds for UC only (OR, 0.29; 95% CI, 0.12-0.71). Vaccination against pertussis (OR, 2.08; 95% CI, 1.07-4.03) and polio (OR, 2.38; 95% CI, 1.04-5.43) increased the odds for IBD, whereas measles infection increased the odds for UC (OR, 3.50; 95% CI, 1.15-10.6). Low consumption of fibres and high consumption of sugar were significantly associated with development of CD and UC. Smoking increased the risk for CD and protected against UC.

CONCLUSION

Among Danish patients with CD and UC belonging to an unselected cohort, disease occurrence was found to be associated both with well-known factors such as smoking and appendectomy, and with more debated factors including breastfeeding, tonsillectomy, childhood vaccinations, childhood infections, and dietary intake of fibres and sugar.

The appendix may protect against Clostridium difficile recurrence

BACKGROUND & AIMS

Several risk factors have been identified for the development of recurrent Clostridium difficile infection (CDI) that alter host immunity and disrupt colonic flora. Although the function of the appendix has been debated, its active, gut-associated lymphoid tissue and biofilm production indicate potential roles in recovery from initial CDI and protection against recurrent CDI. We investigated whether the presence or absence of an appendix is associated with CDI recurrence.

METHODS

We reviewed the medical records of adult inpatients with CDI who were admitted to a tertiary-care teaching hospital from 2005 to 2007 to identify those with and without an appendix. The primary dependent variable for statistical analysis was CDI recurrence.

RESULTS

In a multivariate analysis of 11 clinical variables, the presence of an appendix was associated inversely with CDI recurrence (P < .0001; adjusted relative risk, .398). Age older than 60 years also was associated with CDI recurrence (P = .0280; adjusted relative risk, 2.44).

CONCLUSIONS

The presence of an appendix has a significant and independent, inverse association with CDI recurrence, but this finding requires validation in a prospective study. Assessing the presence or absence of an appendix might be useful in predicting CDI recurrence.

Familial aggregation in inflammatory bowel disease: Is it genes or environment?

Inflammatory bowel disease (IBD) develops in genetically susceptible individuals due to the influence of environmental factors, leading to an abnormal recognition of microbiota antigens by the innate immune system which triggers an exaggerated immune response and subsequent bowel tissue damage. IBD has been more frequently found in families, an observation that could be due to either genetic, environmental or both types of factors present in these families. In addition to expanding our knowledge on IBD pathogenesis, defining the specific contribution to familial IBD of each one of these factors might have also clinical usefulness. We review the available evidence on familial IBD pathogenesis.

The role of appendicectomy in the subsequent development of inflammatory bowel disease: a UK-based study

BACKGROUND

Several studies have shown an inverse relationship between appendicectomy and subsequent development of inflammatory bowel disease (IBD), although these findings remain contentious. This study aims to further elucidate the role appendicitis/appendicectomy has in the development of IBD.

METHOD

All patients undergoing appendicectomy at Hereford County Hospital between 1986 and 2005 were identified from pathology records. Those already diagnosed with IBD were excluded. Age- and sex-matched controls were randomly selected from a database of orthopaedic clinic attendees. Those with prior history of IBD or appendicectomy were excluded. The incidence of IBD was determined by cross-referencing with the histology database, colonoscopy database and IBD register.

RESULTS

Three thousand eight hundred twenty-nine patients were included in each group, with mean follow-up of 12 +/- 5.9 years. Twelve patients in the appendicectomy group developed IBD. Mean age at diagnosis was 30.3 years, and mean interval from appendicectomy of 3.7 years. Age at appendicectomy and appendicectomy for appendicitis conferred no benefit (Mann-Whitney test, p = 0.991). Eleven patients in the control group developed IBD, with no significant differences in any of the measured outcomes.

CONCLUSION

This study has shown no relationship between appendicitis/appendicectomy and development of IBD.

Appendicectomy as a therapy for ulcerative proctitis

OBJECTIVES

Available data regarding whether appendicectomy performed after the onset of ulcerative colitis can modulate its clinical course are currently limited. This study aimed at addressing this issue.

METHODS

In this study, we report a prospective case series of 30 adult patients (median age 35 years, range 17-70 years; male/female: 11/19) with ulcerative proctitis (median duration of symptoms 5 years, range 8 months to 30 years; median Simple Clinical Colitis Activity Index score 9, range 7-12), who underwent appendicectomy in the absence of any history suggestive of previous appendicitis. Patients were subsequently followed up clinically with the assessment of the Simple Clinical Colitis Activity Index for a median of 14 months (range 9-32 months).

RESULTS

After appendicectomy, the clinical activity index improved significantly to a median score of 2 (range 0-12) (P<0.0005). The improvement in the clinical activity index occurred in 27 of 30 (90%) patients, whereas the index remained unchanged in the remaining 3 of 30 (10%) patients. Furthermore, 12 of 30 (40%) patients experienced a complete resolution of symptoms (clinical activity index score of 0) by 12 months, such that all pharmacological treatments could be withdrawn, and have remained in remission off all previous treatments for a median 9 months (range 6-25 months). The time required for a complete resolution of symptoms post appendicectomy ranged from 1 to 12 months (median 3 months) (Kaplan-Meier analysis). None of the clinical or histological factors analyzed were significantly associated with post-appendicectomy outcome.

CONCLUSIONS

This case series, the largest reported so far, provides rationale for controlled trials to properly evaluate the possible role of appendicectomy in the treatment of ulcerative proctitis.

Appendicitis, mesenteric lymphadenitis, and subsequent risk of ulcerative colitis: cohort studies in Sweden and Denmark

OBJECTIVE

To determine whether the repeatedly observed low risk of ulcerative colitis after appendicectomy is related to the appendicectomy itself or the underlying morbidity, notably appendicitis or mesenteric lymphadenitis.

DESIGN

Nationwide cohort studies.

SETTING

Sweden and Denmark.

PARTICIPANTS

709 353 Swedish (1964-2004) and Danish (1977-2004) patients who had undergone appendicectomy were followed up for subsequent ulcerative colitis. The impact of appendicectomy on risk was also studied in 224 483 people whose parents or siblings had inflammatory bowel disease.

MAIN OUTCOME MEASURES

Standardised incidence ratios and rate ratios as measures of relative risk.

RESULTS

During 11.1 million years of follow-up in the appendicectomy cohort, 1192 patients developed ulcerative colitis (10.8 per 100 000 person years). Appendicectomy without underlying inflammation was not associated with reduced risk (standardised incidence ratio 1.04, 95% confidence interval 0.95 to 1.15). Before the age of 20, however, appendicectomy for appendicitis (0.45, 0.39 to 0.53) or mesenteric lymphadenitis (0.65, 0.46 to 0.90) was associated with significant risk reduction. A similar pattern was seen in those with affected relatives, whose overall risk of ulcerative colitis was clearly higher than the background risk (1404 observed v 446 expected; standardised incidence ratio 3.15, 2.99 to 3.32). In this cohort, appendicectomy without underlying appendicitis did not modify risk (rate ratio 1.04, 0.66 to 1.55, v no appendicectomy), while risk after appendicectomy for appendicitis was halved (0.49, 0.31 to 0.74).

CONCLUSIONS

In individuals with or without a familial predisposition to inflammatory bowel disease, appendicitis and mesenteric lymphadenitis during childhood or adolescence are linked to a significantly reduced risk of ulcerative colitis in adulthood. Appendicectomy itself does not protect against ulcerative colitis.

Clinical characteristics of inflammatory bowel disease in Turkey: a multicenter epidemiologic survey

AIM

To investigate the epidemiologic and clinical characteristics of inflammatory bowel disease (IBD) patients in a large multicenter, countrywide, hospital-based study in Turkey.

MATERIALS AND METHODS

Twelve centers uniformly distributed throughout Turkey reported through a questionnaire the new IBD cases between 2001 and 2003. The incidence of ulcerative colitis (UC) and Crohn's disease (CD) has been reported per 100,000 people. Epidemiologic features and clinical characteristics of both diseases were analyzed.

RESULTS

During the study period, 661 patients of UC and 216 patients of CD were identified. The incidence in the referral population was 4.4/100,000 and 2.2/100,000 for UC and CD, respectively. The age of the patients showed the characteristic biphasic distribution with 2 peaks between 20 and 30 and 50 and 70 years. A male predominance was observed in both diseases. A history of smoking was detected in 15.5% of UC patients and 49.3% of patients with CD. Family history was positive in 4.4% in UC and 8.3% in CD patients. Concomitant amebiasis was observed in 17.3% of patients with UC and 1.3% of patients with CD. A history of appendectomy was reported in 15% of patients with CD and only 3% of patients with UC. Both extraintestinal and local complications were more frequent in CD patients, whereas arthritis was most common in both diseases.

CONCLUSIONS

IBDs are frequently encountered in Turkey. IBD incidence is lower than North and West Europe but close to Middle East in our country. The majority of IBD cases are diagnosed in young people (20 to 40 y) with predominance in males. The rate of both intestinal and extraintestinal complications in our population was low when compared with the data reported in the literature. IBD and especially UC, can coexist with amebiasis or become manifest with amebic infestation. The presence of concomitant ameba may create confusion and cause dilemmas in the diagnosis and treatment of UC.

The risk of developing Crohn's disease after an appendectomy: a meta-analysis

BACKGROUND

Studies exploring the association between appendectomy and Crohn's disease (CD) have reported conflicting findings. We conducted a systematic review of the literature and a meta-analysis to assess the risk of CD following an appendectomy and determine the effect of time between appendectomy and CD diagnosis.

METHODS

MEDLINE was used to identify observational studies evaluating the association between appendectomy and CD. Authors were contacted when data were insufficient. Relative risks (RR) with 95% confidence intervals (CI) were calculated using a random effects model. Studies that analyzed their data by the interval between the appendectomy and the diagnosis of CD were assessed separately. The Woolf chi(2) statistic was used to test for homogeneity. Egger's test was used to evaluate publication bias.

RESULTS

The summary RR estimate for CD following an appendectomy was significantly elevated (RR 1.61, 95% CI 1.28-2.02), though heterogeneity was observed (P < 0.0001). The risk was elevated within the first year following the operation (RR 6.69, 95% CI 5.42-8.25). The risk of CD was also significantly increased 1-4 yr following an appendectomy (RR 1.99, 95% CI 1.66- 2.38); however, after 5 yr or more, the risk fell to baseline levels (RR 1.08, 95% CI 0.99-1.18). Publication bias was not detected (P = 0.2).

CONCLUSION

The meta-analysis demonstrated a significant risk of CD following an appendectomy, though heterogeneity was observed between the studies. The elevated risk early after an appendectomy, which diminishes thereafter, likely reflects diagnostic problems in patients with incipient CD.

Appendectomy, smoking habits and the risk of developing ulcerative colitis: a case control study in private practice setting

OBJECTIVES

The strongest environmental factors identified for ulcerative colitis (UC) are cigarette smoking and appendectomy. However, most studies have been performed using case-controls from hospital-based populations. The purpose of this study was to compare the history of previous appendectomy and smoking habits in a group of patients with UC and a control group, followed by gastroenterologists in private practice.

METHODS

We performed a case control study in which 100 physicians recruited UC-patients and age and sex matched controls. Data were collected during a single visit. Based on a standardized questionnaire, UC patients and controls were divided into never, former or current smokers, and into subjects with or without a previous history of appendectomy.

RESULTS

One hundred and ninety eight age- and sex-matched pairs of UC patients and controls were included. The prevalence of appendectomy in the UC-patients and control group was 12% and 46%, respectively. The pairwise-matched OR of ulcerative colitis for previous appendectomy was 0.10 (95% CI, 0.05-0.21) (P<0.0001). The OR for former and never smokers versus current smokers was 2.40 (95% CI 1.31-4.38) (P=0.004). In UC-patients, the OR of family history of UC compared with controls was 2.80 (95% CI, 1.01-7.77) (P=0.048).

CONCLUSIONS

This case-control study confirmed a strong negative correlation between both appendectomy and tobacco smoking, and ulcerative colitis in patients followed-up by gastroenterological practitioners.

Inflammatory bowel disease: past, present, and future

Crohn's disease and ulcerative colitis, collectively known as the inflammatory bowel diseases (IBD), are largely diseases of the twentieth century, and are associated with the rise of modern, Westernized industrial society. Although the causes of these diseases remain incompletely understood, the prevailing model is that the intestinal flora drives an unmitigated intestinal immune response and inflammation in the genetically susceptible host. A review of the past and present of these diseases shows that detailed description preceded more fundamental elucidation of the disease processes. Working out the details of disease pathogenesis, in turn, has yielded dividends in more focused and effective therapy for IBD. This article highlights the key descriptions of the past, and the pivotal findings of current studies in disease pathogenesis and its connection to medical therapy. Future directions in the IBD will likely explicate the inhomogeneous causes of these diseases, with implications for individualized therapy.

Diagnosis underlying appendectomy and coeliac disease risk

BACKGROUND

Earlier studies suggest that appendectomy is associated with a substantially reduced risk of certain types of bowel inflammation such as ulcerative colitis, particularly where the underlying diagnosis is acute appendicitis. Previous research on appendectomy and coeliac disease is inconsistent, based on small numbers with retrospective data collection, and has not differentiated between different diagnoses underlying appendectomy.

OBJECTIVE

To investigate the association of diagnosis underlying appendectomy with coeliac disease.

METHODS

We used Cox regression to study the risk of later appendectomy in more than 14,000 individuals with coeliac disease and 68,000 referents without coeliac disease, identified through the Swedish National Registers 1964-2003, and conditional logistic regression to study the risk of coeliac disease associated with a history of prior appendectomy. Appendectomy was categorised according to the underlying diagnosis: perforated appendicitis, non-perforated appendicitis, and appendectomy without appendicitis.

RESULTS

Overall, coeliac disease was negatively associated with perforated appendicitis (hazard ratio=0.78, 95% confidence interval=0.60-1.01), not associated with non-perforated appendicitis (hazard ratio=1.11, 95% confidence interval=0.99-1.25), but positively associated with appendectomy without appendicitis (hazard ratio=1.58, 95% confidence interval=1.32-1.89). The magnitudes of the relative risks were similar irrespective of whether coeliac disease occurred prior to or after appendectomy.

CONCLUSION

Coeliac disease and perforated appendicitis are negatively associated irrespective of the timing of the conditions. Not surprisingly, CD increases the risk for appendectomy without appendicitis.

Environmental factors in inflammatory bowel disease: a co-twin control study of a Swedish-Danish twin population

BACKGROUND

Genetics and environmental factors are implicated in the etiology of inflammatory bowel disease (IBD). We studied environmental factors in a population-based Swedish-Danish twin cohort using the co-twin control method.

SUBJECTS AND METHODS

A questionnaire was sent to 317 twin pairs regarding markers of exposures in the following areas: infections/colonization and diet as well as smoking, appendectomy, and oral contraceptives. Odds ratios (OR) were calculated by conditional logistic regression. When confounding appeared plausible, multivariate conditional logistic regression was added. The questions were also divided into topic groups, and adjustment was made for multiple testing within each of the groups.

RESULTS

The response rate to the questionnaire was 83%. In consideration of the study design, only discordant pairs were included (Crohn's disease [CD], n = 102; ulcerative colitis [UC], n = 125). Recurrent gastrointestinal infections were associated with both UC (OR, 8.0; 95% confidence interval [CI], 1.0-64) and CD (OR, 5.5; 95% CI, 1.2-25). Hospitalization for gastrointestinal infections was associated with CD (OR, 12; 95% CI, 1.6-92). Smoking was inversely associated with UC (OR, 0.4; 95% CI, 0.2-0.9) and associated with CD (OR, 2.9; 95% CI, 1.2-7.1).

CONCLUSIONS

The observed associations indicate that markers of possible infectious events may influence the risk of IBD. Some of these effects might be mediated by long-term changes in gut flora or alterations in reactivity to the flora. The influence of smoking in IBD was confirmed.

Prior appendectomy and the phenotype and course of Crohn's disease

AIM

To determine whether prior appendectomy modifies the phenotype and severity of Crohn's disease.

METHODS

Appendectomy status and smoking habits were specified by direct interview in 2838 patients consecutively seen between 1995 and 2004. Occurrence of complications and therapeutic needs were reviewed retrospectively. Additionally, annual disease activity was assessed prospectively between 1995 and 2004 in patients who had not had ileocecal resection and of a matched control group.

RESULTS

Compared to 1770 non-appendectomized patients, appendectomized patients more than 5 years before Crohn's disease diagnosis (n=716) were more often females, smokers, with ileal disease. Cox regression showed that prior appendectomy was positively related to the risk of intestinal stricture (adjusted hazard ratio, 1.24; 95% confidence interval, 1.13 to 1.36; P=0.02) and inversely related to the risk of perianal fistulization (adjusted hazard ratio, 0.75; 95% confidence interval, 0.68 to 0.83; P=0.002). No difference was observed between the two groups regarding the therapeutic needs, except for an increased risk of surgery in appendectomized patients, attributable to the increased prevalence of ileal disease. Between 1995 and 2004, Crohn's disease was active during 50% of years in appendectomized patients (1318 out of 2637 patient-years) and 51% in non-appendectomized patients (1454 out of 2841 patient-years; NS).

CONCLUSION

Prior appendectomy is associated with a more proximal disease and has an increased risk of stricture and a lesser risk of anal fistulization. However, the severity of the disease is unaffected.

Granulomatous appendicitis and the appendix in idiopathic inflammatory bowel disease

Granulomatous appendicitis is a rare condition, accounting for less than 2% of all cases of appendicitis. The initial belief that it represented a manifestation of Crohn's disease is incorrect in the great majority of cases, as only 5-10% of patients with granulomatous appendicitis develop Crohn's disease elsewhere in their gastrointestinal tract. The remaining etiologies are diverse. Unusual causes include sarcoidosis, foreign body reaction, and infection by mycobacteria, fungi, or parasites. These conditions combined explain less than 10% of cases. More recently, two etiologies have been recognized that potentially account for most of the previous "idiopathic" cases of granulomatous appendicitis. The first is infection by pathogenic Yersinia species, now demonstrated in approximately 25% of cases. The second cause may be the most common of all, namely subacute/recurrent appendicitis with interval appendectomy. This condition likely produces a granulomatous reaction in relation to a protracted secondary inflammatory response to appendicitis and temporizing measures to delay appendectomy, such as antibiotic therapy. Thus, granulomatous appendicitis only rarely represents a manifestation of Crohn's disease. Rather, the overwhelming majority of patients with this condition are cured by appendectomy alone. The appendix, however, can be involved by idiopathic inflammatory bowel disease, both Crohn's disease and ulcerative colitis. It can be involved by ulcerative colitis in patients with distal colonic involvement and sparing of the intervening colonic segment, a phenomenon known as the appendiceal "skip lesion" or "cecal patch" and this pattern of involvement does not necessarily indicate Crohn's disease. Interestingly, appendectomy has been shown to provide some protection against developing inflammatory bowel disease and in reducing its severity if performed before the onset of disease.

Worse clinical course of disease in Crohn's patients with previous appendectomy

OBJECTIVES

The aim of the present study was to assess the effect of previous appendectomy in a series of Crohn's disease (CD) patients on the clinical characteristics and course of disease.

METHODS

Demographic and clinical data were retrospectively analysed for 129 consecutive outpatients (68 men and 61 women, median age 38 years) with CD. For each patient, information concerning appendectomy, indication for surgery (acute/chronic) and the date of surgery were recorded. The date of the appendectomy in relation to the date of CD diagnosis was carefully assessed in order to evaluate the precise relationship between the two events. A total of 129 CD patients who had not undergone previous appendectomy served as controls. The severity of disease was assessed retrospectively by evaluating the need for systemic steroids, immunosuppressants and surgical treatment for CD, particularly resective procedures.

RESULTS

Forty-one CD patients (31.8%) underwent appendectomy before the diagnosis of disease. Appendectomy before diagnosis showed a negative association with colonic disease localization and with articular manifestations. In addition, the 41 patients with previous appendectomy had a significantly greater risk of surgery, particularly resective. Multivariate analysis confirmed appendectomy performed before diagnosis as an independent risk factor for surgery; on the contrary, colonic site and inflammatory type of disease were independent factors protecting against surgery. Although current smokers were at an increased risk of surgical treatment, a smoking habit alone did not seem to be relevant at the multivariate analysis.

CONCLUSION

The results of this study indicate a worse clinical course of CD in patients appendicectomized before diagnosis.

Clinical epidemiology of inflammatory bowel disease: Incidence, prevalence, and environmental influences

Although the incidence and prevalence of ulcerative colitis and Crohn's disease are beginning to stabilize in high-incidence areas such as northern Europe and North America, they continue to rise in low-incidence areas such as southern Europe, Asia, and much of the developing world. As many as 1.4 million persons in the United States and 2.2 million persons in Europe suffer from these diseases. Previously noted racial and ethnic differences seem to be narrowing. Differences in incidence across age, time, and geographic region suggest that environmental factors significantly modify the expression of Crohn's disease and ulcerative colitis. The strongest environmental factors identified are cigarette smoking and appendectomy. Whether other factors such as diet, oral contraceptives, perinatal/childhood infections, or atypical mycobacterial infections play a role in expression of inflammatory bowel disease remains unclear. Additional epidemiologic studies to define better the burden of illness, explore the mechanism of association with environmental factors, and identify new risk factors are needed.

Does Appendectomy Reduce the Risk of Ulcerative Colitis?

BACKGROUND

Persons who have had an appendectomy are less prone to develop ulcerative colitis than those who have not. The underlying mechanism and the clinical use of this finding are unknown.

METHODS

Two competing hypotheses were examined: (1) the inverse association between appendectomy and ulcerative colitis is conferred by a mutual determinant such as genes, and (2) the appendix itself has biologic effects that promote the development of ulcerative colitis. We performed a population-based cohort study of all 234,559 persons who had an appendectomy performed in Denmark 1977 through 1999. We used a bidirectional cohort design, calculating the standardized incidence rate of ulcerative colitis both before and after the appendectomy. If the hypothesis of a constant, confounding factor were true, incidence rates of ulcerative colitis would be equal before and after appendectomy. If the incidence of ulcerative colitis were lower after appendectomy than before, it would support the second hypothesis and a true protective effect of the appendectomy. We controlled confounding by age and sex using direct standardization.

RESULTS

Of 234,559 persons who had an appendectomy, 559 developed ulcerative colitis during a mean follow up of 17.5 years. The standardized incidence rate of ulcerative colitis was lower in the postappendectomy period than in the preappendectomy period (incidence rate ratio = 0.74; 95% confidence interval = 0.62-0.88).

CONCLUSIONS

The inverse association between appendectomy and ulcerative colitis is not explained by time-stable factors such as genes. Appendectomy might have a genuine protective effect toward development of ulcerative colitis.

Multiple myenteric networks in the human appendix

The general histological organization of the appendix, including its innervation, is believed to be generally similar to that of the large intestine. However, several authors described an unusual arrangement of the myenteric ganglia within the appendiceal muscle, but conflicting reports do not allow clear conclusions on this matter. The aim of this work was to examine the appendiceal innervation in detail. The myenteric plexus of the human appendix was examined using sections and whole mount preparations. Human small and large intestines were used for comparison. The nerves were stained using immunohistochemistry, enzyme histochemistry for NADPH-diaphorase, and vital staining with 4-(4-diethylaminostyryl)-methylpyridinium iodide. Appendices from rabbits were also studied. In most cases, the innervation of the external muscle of the appendix consisted of three concentric networks of ganglia. These networks were located both between the circular and longitudinal muscle layers and within them. The middle network made connections with the other two. Such arrangement was not observed in the human small and large intestines. The myenteric plexus in the rabbit appendix displayed a much smaller degree of three-dimensional distribution compared with that of the human appendix. It is concluded that the myenteric plexus in the human appendix consists of several distinct networks, and appears to be unique in comparison with the other parts of the intestine.

Appendectomy is followed by increased risk of Crohn's disease

BACKGROUND & AIMS

Appendectomy is associated with a low risk of subsequent ulcerative colitis. This study analyzes the risk of Crohn's disease after appendectomy.

METHODS

We followed-up 212,218 patients with appendectomy before age 50 years and a cohort of matched controls, identified from the Swedish Inpatient Register and the nationwide Census, for any subsequent diagnosis of Crohn's disease.

RESULTS

An increased risk of Crohn's disease was found for more than 20 years after appendectomy, with incidence rate ratio 2.11 (95% confidence interval [CI], 1.21-3.79) after perforated appendicitis, 1.85 (95% CI, 1.10-3.18) after nonspecific abdominal pain, 2.15 (95% CI, 1.25-3.80) after mesenteric lymphadenitis, 2.52 (95% CI, 1.43-4.63) after other diagnoses. After nonperforated appendicitis, there was an increased risk among women but not among men (incidence rate ratio 1.37; 95% CI, 1.03-1.85, respectively, 0.89, 95% CI, 0.64-1.24). Patients operated on before age 10 years had a low risk (incidence rate ratio 0.48, 95% CI, 0.23-0.97). Crohn's disease patients with a history of perforated appendicitis had a worse prognosis.

CONCLUSIONS

Appendectomy is associated with an increased risk of Crohn's disease that is dependent on the patient's sex, age, and the diagnosis at operation. The pattern of associations suggests a biologic cause.