Addition of metronidazole to azathioprine for the prevention of postoperative recurrence of Crohn's disease: a randomized, double-blind, placebo-controlled trial

Medical therapies for postoperative Crohn's disease

Postoperative recurrence of Crohn's disease is common and requires a multidisciplinary approach between surgeons and gastroenterologists in the perioperative and postoperative period to improve outcomes in this patient population. Endoscopic recurrence precedes clinical and surgical recurrence and endoscopic monitoring is crucial to guide postoperative management. Risk stratification of patients is recommended to guide early prophylactic management, and follow-up endoscopic monitoring can guide intensification of therapy. This review summarizes evidence behind postoperative recurrence rates, disease monitoring techniques, nonbiologic and biologic therapies available to prevent and treat postoperative recurrence, risk factors associated with recurrence, and postoperative management strategies guided by endoscopic monitoring.

Gut Microbiota Profiles and Microbial-Based Therapies in Post-operative Crohn's Disease: A Systematic Review

Background and Aims: Gut microbiota recolonization after intestinal resection had been reported to be associated with post-operative recurrence in Crohn's disease (CD). However, the results of different studies are inconsistent and even contradictory. In addition, knowledge on the efficacy of microbial-based therapies in preventing post-operative recurrence of CD is limited. Therefore, the aim of this review was to investigate gut microbiota profiles in patients with CD before and after surgery and evaluate microbial-based therapies in preventing post-operative recurrence. Methods: Electronic databases were searched from inception to 31 June 2020 using predefined terms. Studies that investigated gut microbiota pre- and post-intestinal resection, and microbial-based therapies in preventing post-operative recurrence, were eligible. Study quality was assessed using either the Newcastle-Ottawa scale or Jadad scoring system. Results: Twelve studies investigating gut microbiota of CD patients suffering from operation, and other 12 studies evaluating the efficacy of antibiotics and probiotics, were included in our review. The mucosa-associated microbiota in surgical biopsy of CD patients is significantly distinct from that in normal mucosa from healthy subjects. Gut microbiota recolonization following surgery might be associated with post-operative recurrence in CD patients. Furthermore, CD patients with post-operative recurrence presented a gain in pro-inflammatory pathogenic bacteria and a loss in short-chain fatty acid-producing bacteria before and after surgery. However, no consistent bacteria or metabolites were found to predict the post-operative recurrence of CD. Additionally, microbial-based therapies are deficient and present restricted widespread clinical utility due to several deficiencies. Conclusion: Recurrence-associated bacteria observed pre- and post- operation might be promising in preventing the post-operative recurrence of CD. Furthermore, potential microbe biomarkers for predicting subsequent disease recurrence should be validated with larger sample sizes using more rigorous and standardized methodologies.

Management and outcomes of patients with Crohn's disease with first vs multiple surgeries: results from the PRACTICROHN study

Background

Surgery in Crohn's disease (CD) may be associated with poor prognosis and clinical and surgical recurrence. The aim of this study was to describe and compare the post-operative management and outcomes of patients with CD who underwent first vs recurrent surgeries.

Methods

Observational study that included adult CD patients from 26 Spanish hospitals who underwent ileocolonic resection with ileocolonic anastomosis between January 2007 and December 2010. Data were retrospectively collected from the medical records.

Results

Data from 314 patients were analysed, of whom 262 (83%) underwent first surgery and 52 (17%) referred to previous CD surgeries. Baseline characteristics were similar between the two groups except for a higher rate of stricturing behavior at diagnosis among re-operated patients (P = 0.03). After surgery, a higher proportion of re-operated patients received prophylactic treatment with immunomodulators compared with patients with first surgery (P = 0.04). In re-operated patients, time to clinical recurrence was not associated with the fact of receiving or not prophylaxis, whereas, in patients with first surgery, recurrence-free survival was greater when prophylaxis was received (P = 0.03).

Conclusions

After surgery, a higher proportion of patients with previous surgeries received prophylactic treatment with immunomodulators compared with patients with first surgery. Although prophylactic treatment was beneficial for preventing clinical recurrence in patients operated on for the first time, it did not significantly reduce the risk of further recurrence in patients with previous surgeries. This suggests that effective prophylactic therapies are still needed in this subset of patients.

Interventions for maintenance of surgically induced remission in Crohn's disease: a network meta-analysis

BACKGROUND

Crohn's disease (CD) is a chronic disease of the gut. About 75% of people with CD undergo surgery at least once in their lifetime to induce remission. However, as there is no known cure for the disease, patients usually experience a recurrence even after surgery. Different interventions are routinely used in maintaining postsurgical remission. There is currently no consensus on which treatment is the most effective.

OBJECTIVES

To assess the effects and harms of interventions for the maintenance of surgically induced remission in Crohn's disease and rank the treatments in order of effectiveness.

SEARCH METHODS

We searched the Cochrane IBD Group Specialized Register, CENTRAL, MEDLINE, and Embase from inception to 15 January 2019. We also searched reference lists of relevant articles, abstracts from major gastroenterology meetings, ClinicalTrials.gov, and the WHO ICTRP. There was no restriction on language, date, or publication status.

SELECTION CRITERIA

We considered for inclusion randomised controlled trials (RCTs) that compared different interventions used for maintaining surgically induced remission in people with CD who were in postsurgical remission. Participants had to have received maintenance treatment for at least three months. We excluded studies assessing enteral diet, diet manipulation, herbal medicine, and nutritional supplementation.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected relevant studies, extracted data, and assessed the risk of bias. Any disagreements were resolved by discussion or by arbitration of a third review author when necessary. We conducted a network meta-analysis (NMA) using a Bayesian approach through Markov Chain Monte Carlo (MCMC) simulation. For the pairwise comparisons carried out in Review Manager 5, we calculated risk ratios (RR) with their corresponding 95% confidence intervals (95% CI). For the NMA, we presented hazard ratios (HR) with corresponding 95% credible intervals (95% CrI) and reported ranking probabilities for each intervention. For the NMA, we focused on three main outcomes: clinical relapse, endoscopic relapse, and withdrawals due to adverse events. Data were insufficient to assess time to relapse and histologic relapse. Adverse events and serious adverse events were not sufficiently or objectively reported to permit an NMA. We used CINeMA (Confidence in Network Meta-Analysis) methods to evaluate our confidence in the findings within networks, and GRADE for entire networks.

MAIN RESULTS

We included 35 RCTs (3249 participants) in the review. The average age of study participants ranged between 33.6 and 38.8 years. Risk of bias was high in 18 studies, low in four studies, and unclear in 13 studies. Of the 35 included RCTs, 26 studies (2581 participants; 9 interventions) were considered eligible for inclusion in the NMA. The interventions studied included 5-aminosalicylic acid (5-ASA), adalimumab, antibiotics, budesonide, infliximab, probiotics, purine analogues, sulfasalazine, and a combination of sulfasalazine and prednisolone. This resulted in 30 direct contrasts, which informed 102 mixed-treatment contrasts.The evidence for the clinical relapse network (21 studies; 2245 participants) and endoscopic relapse (12 studies; 1128 participants) were of low certainty while the evidence for withdrawal due to adverse events (15 studies; 1498 participants) was of very low certainty. This assessment was due to high risk of bias in most of the studies, inconsistency, and imprecision across networks. We mainly judged individual contrasts as of low or very low certainty, except 5-ASA versus placebo, the evidence for which was judged as of moderate certainty.We ranked the treatments based on effectiveness and the certainty of the evidence. For clinical relapse, the five most highly ranked treatments were adalimumab, infliximab, budesonide, 5-ASA, and purine analogues. We found some evidence that adalimumab (HR 0.11, 95% Crl 0.02 to 0.33; low-certainty evidence) and 5-ASA may reduce the probability of clinical relapse compared to placebo (HR 0.69, 95% Crl 0.53 to 0.87; moderate-certainty evidence). However, budesonide may not be effective in preventing clinical relapse (HR 0.66, 95% CrI 0.27 to 1.34; low-certainty evidence). We are less confident about the effectiveness of infliximab (HR 0.36, 95% CrI 0.02 to 1.74; very low-certainty evidence) and purine analogues (HR 0.75, 95% CrI 0.55 to 1.00; low-certainty evidence). It was unclear whether the other interventions reduced the probability of a clinical relapse, as the certainty of the evidence was very low.Due to high risk of bias and limited data across the network, we are uncertain about the effectiveness of interventions for preventing endoscopic relapse. Whilst there might be some evidence of prevention of endoscopic relapse with adalimumab (HR 0.10, 95% CrI 0.01 to 0.32; low-certainty evidence), no other intervention studied appeared to be effective.Due to high risk of bias and limited data across the network, we are uncertain about the effectiveness of interventions for preventing withdrawal due to adverse events. Withdrawal due to adverse events appeared to be least likely with sulfasalazine (HR 1.96, 95% Crl 0.00 to 8.90; very low-certainty evidence) and most likely with antibiotics (HR 53.92, 95% Crl 0.43 to 259.80; very low-certainty evidence). When considering the network as a whole, two adverse events leading to study withdrawal (i.e. pancreatitis and leukopenia) occurred in more than 1% of participants treated with an intervention. Pancreatitis occurred in 2.8% (11/399) of purine analogue participants compared to 0.17% (2/1210) of all other groups studied. Leukopenia occurred in 2.5% (10/399) of purine analogue participants compared to 0.08% (1/1210) of all other groups studied.

AUTHORS' CONCLUSIONS

Due to low-certainty evidence in the networks, we are unable to draw conclusions on which treatment is most effective for preventing clinical relapse and endoscopic relapse. Evidence on the safety of the interventions was inconclusive, however cases of pancreatitis and leukopenia from purine analogues were evident in the studies. Larger trials are needed to further understand the effect of the interventions on endoscopic relapse.

Azathioprine and 6-mercaptopurine for maintenance of surgically-induced remission in Crohn's disease

BACKGROUND

Crohn's disease (CD) is a chronic relapsing inflammatory condition and maintenance of remission is a major issue as many patients fail to achieve remission with medical management and require surgical interventions. Purine analogues such as azathioprine (AZA) and 6-mercaptopurine (6-MP) have been used to maintain surgically-induced remission in CD, but the effectiveness, tolerability and safety of these agents remains controversial.

OBJECTIVES

To assess the efficacy and safety of purine analogues (AZA and 6-MP) for maintenance of surgically-induced remission in CD.

SEARCH METHODS

We searched PubMed, MEDLINE, Embase, CENTRAL, and the Cochrane IBD Group Specialized Register from inception to 26 July 2018 (and from inception to 31 July 2019). In addition, we searched reference lists of all included studies and relevant reviews, conference proceedings and trials registers.

SELECTION CRITERIA

Randomised controlled trials (RCTs) with a duration of at least three months that enrolled adults and children with surgically-induced remission of CD and compared AZA or 6-MP to no treatment, placebo or any other active intervention were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility, extracted data, assessed the risk of bias and assessed the certainty of the evidence using GRADE. The primary outcome was clinical relapse. Secondary outcomes included endoscopic relapse, radiologic and surgical relapse, adverse events (AEs), serious adverse events (SAEs), withdrawal due to AEs and health-related quality of life.

MAIN RESULTS

Ten RCTs with a total of 928 participants were included. Study participants were adults recruited from university clinics and gastroenterology hospitals who received interventions post-surgery for a duration between 12 to 36 months. Most study participants were recruited less than three months after surgery in all except one study where participants were recruited between 6 to 24 months post-surgery. One study was rated as low risk of bias, six studies were rated high risk of bias and three were rated unclear risk of bias.There was moderate certainty evidence that purine analogues are more efficient for preventing clinical relapse than placebo. At 12 to 36 months, 51% (109/215) of AZA/6-MP participants relapsed compared to 64% (124/193) of placebo participants (RR 0.79; 95% CI 0.67 to 0.92; 408 participants; 3 studies; I² = 0%; moderate certainty evidence). The certainty of the evidence regarding the efficacy of AZA or 6-MP for maintaining postoperative clinical remission compared to 5-ASA compounds was low. At 12 to 24 months , 64% (113/177) of purine analogue participants relapsed compared to 59% (101/170) of 5-ASA participants (RR 1.05; 95% CI 0.89 to 1.24; 347 participants; 4 studies; I² = 8%; low certainty evidence). The certainty of evidence that purine analogues are inferior for preventing postsurgical clinical relapse compared to tumour necrosis factor alpha agents (anti-TNF-α) was very low. At 12 to 24 months, 43% (29/67) of AZA participants relapsed compared to 14% (10/72) of anti-TNF-α participants (RR 2.89; 95% CI 1.50 to 5.57; 139 participants; 3 studies; I² = 0%; very low certainty evidence).The effect of purine analogues compounds on AEs compared to placebo or any active treatment was uncertain, as the quality of evidence ranged from very low to low. After 12 to 24 months, 14% (12/87) of purine analogue participants experienced an AE compared to 10% (8/81) of placebo participants (RR 1.36; 95% CI 0.57 to 3.27; 168 participants; 2 studies; I² = 0%; low certainty evidence). The effect of purine analogues on AEs compared to 5-ASA agents was uncertain. After 12 to 24 months, 41% (73/176) of purine analogue participants had an AE compared to 47% (81/171) of 5-ASA participants (RR 0.89; 95% CI 0.74 to 1.07; 346 participants; 4 studies; I² = 15%; low certainty evidence). The effect of purine analogues on AEs in comparison to anti TNF-α agents was uncertain. At 12 to 24 months, 57% (32/56) of AZA participants had an AE compared to 51% (31/61) of anti-TNF-α participants (RR 1.13; 95% CI 0.83 to 1.53; 117 participants; 2 studies; I² = 0%; low certainty evidence). Purine analogue participants were more like than 5-ASA participants to have a SAE (RR 3.39, 95% CI 1.26 to 9.13, 311 participants; 3 studies; I² = 9%; very low certainty evidence), or to withdraw due to an AE (RR 2.21, 95% CI 1.28 to 3.81; 425 participants; 5 studies; I² = 0%; low certainty evidence). Commonly reported AEs across all studies included leucopenia, arthralgia, abdominal pain or severe epigastric intolerance, elevated liver enzymes, nausea and vomiting, pancreatitis, anaemia, nasopharyngitis and flatulence.

AUTHORS' CONCLUSIONS

Moderate certainty evidence suggests that AZA and 6-MP may be superior to placebo for maintenance of surgically-induced remission in participants with CD. There was no clear difference in the number of clinical relapses when purine analogues were compared with 5-ASA agents, however this is based on low certainty evidence. There was very low certainty evidence that AZA and 6-MP are more likely to result in more serious adverse events (SAEs) and withdrawals due to an AE (low certainty) when compared to 5-ASA agents. Very low certainty evidence suggests that purine analogues may be inferior to anti-TNF-α agents, however, no firm conclusions can be drawn. Further research investigating the efficacy and safety of AZA and 6-MP in comparison to other active medications in surgically-induced remission of CD is warranted.

Antibiotics in inflammatory bowel diseases: do we know what we're doing?

Despite the revolution in inflammatory bowel disease (IBD) treatment over the past two decades with the advent of biological therapies, there remains a substantial proportion of patients with inadequate or unsustained response to existent therapies. The overwhelming focus of IBD therapeutics has been targeting mucosal immunity, however with the developing evidence base pointing to the role of gut microbes in the inflammatory process, renewed focus should be placed on the impact of manipulating the microbiome in IBD management. This review provides an overview of the evidence implicating bacteria in the pathogenesis of gut inflammation in IBD and provides an overview of the evidence of antibiotics in IBD treatment. We also suggest a potential role of antibiotics in clinical practice based on available evidence and clinical experience.

Perioperative use of immunosuppressive medications in patients with Crohn's disease in the new "biological era"

Crohn’s disease (CD) is characterized by transmural inflammation of the gastrointestinal tract leading to inflammatory, stricturing and/or and fistulizing disease. Once a patient develops medically refractory disease, mechanical obstruction, fistulizing disease or perforation, surgery is indicated. Unfortunately, surgery is not curative in most cases, underscoring the importance of bowel preservation and adequate perioperative medical management. As many of the medications used to treat CD are immunosuppressive, the concern for postoperative infectious complications and anastomotic healing are particularly concerning; these concerns have to be balanced with preventing and treating residual or recurrent disease. We herein review the available literature and make recommendations regarding the preoperative, perioperative and postoperative administration of immunosuppressive medications in the current era of biological therapy for CD. Standardized algorithms for perioperative medical management would greatly assist future research for optimizing surgical outcomes and preventing disease recurrence in the future.

The Significance of the Enteric Microbiome on the Development of Childhood Disease: A Review of Prebiotic and Probiotic Therapies in Disorders of Childhood

Recent studies have highlighted the fact that the enteric microbiome, the trillions of microbes that inhabit the human digestive tract, has a significant effect on health and disease. Methods for manipulating the enteric microbiome, particularly through probiotics and microbial ecosystem transplantation, have undergone some study in clinical trials. We review some of the evidence for microbiome alteration in relation to childhood disease and discuss the clinical trials that have examined the manipulation of the microbiome in an effort to prevent or treat childhood disease with a primary focus on probiotics, prebiotics, and/or synbiotics (ie, probiotics + prebiotics). Studies show that alterations in the microbiome may be a consequence of events occurring during infancy and/or childhood such as prematurity, C-sections, and nosocomial infections. In addition, certain childhood diseases have been associated with microbiome alterations, namely necrotizing enterocolitis, infantile colic, asthma, atopic disease, gastrointestinal disease, diabetes, malnutrition, mood/anxiety disorders, and autism spectrum disorders. Treatment studies suggest that probiotics are potentially protective against the development of some of these diseases. Timing and duration of treatment, the optimal probiotic strain(s), and factors that may alter the composition and function of the microbiome are still in need of further research. Other treatments such as prebiotics, fecal microbial transplantation, and antibiotics have limited evidence. Future translational work, in vitro models, long-term and follow-up studies, and guidelines for the composition and viability of probiotic and microbial therapies need to be developed. Overall, there is promising evidence that manipulating the microbiome with probiotics early in life can help prevent or reduce the severity of some childhood diseases, but further research is needed to elucidate biological mechanisms and determine optimal treatments.

Optimal delivery of follow-up care after surgery for Crohn's disease: current perspectives

Despite improvements in medical therapies for Crohn’s disease (CD), up to 70% of patients require surgery within 10 years of diagnosis. Surgery is not curative, and almost all patients will experience endoscopic recurrence, and many will go on to clinical recurrence. Identifying patients at high-risk of endoscopic recurrence and standardizing postoperative assessments are essential in preventing clinical recurrence of CD. In this review, we discuss the assessment, monitoring, and treatment of postoperative CD patients. We address the various individual risk factors as well as composite risk factors. Medications used for primary CD treatment can be used in the postoperative setting to prevent endoscopic or clinical recurrence with varying efficacy, although the cost-effectiveness of these approaches are not fully understood. Future directions for postoperative CD management include evaluation of newer biologic agents such as anti-integrin therapy and fecal microbiota transplant for prevention of recurrence. Development of a standard preoperative risk assessment tool to clearly stratify those at high-risk of recurrence is necessary to guide empiric therapy. Lastly, the incorporation of noninvasive testing into disease monitoring will likely lead to early detection of endoscopic recurrence that will allow for tailored treatment to prevent clinical recurrence.

Anti-tuberculous therapy for maintenance of remission in Crohn's disease

BACKGROUND

There have been a number of studies with conflicting results which have examined the effect of anti-tuberculous therapy in Crohn's disease. A meta-analysis was performed to evaluate the use of anti-tuberculous therapy for the maintenance of remission in Crohn's disease.

OBJECTIVES

To evaluate the effects of anti-tuberculous therapy for the maintenance of remission in patients with Crohn's disease.

SEARCH METHODS

We searched MEDLINE, EMBASE, the Cochrane LIbrary, and the Cochrane IBD Group Specialized Register from inception to June 22, 2015.

SELECTION CRITERIA

Randomized controlled trials (RCTs) of anti-tuberculous therapy compared to placebo or another active therapy in patients with quiescent Crohn's disease were considered for inclusion.

DATA COLLECTION AND ANALYSIS

At least two authors independently extracted data and assessed the quality of included studies using the Cochrane risk of bias tool. We calculated the risk ratio (RR) and corresponding 95% confidence interval (CI) for dichotomous outcomes.. The primary outcome was relapse. Secondary outcomes included adverse events, withdrawals due to adverse events and serious adverse events. All data were analyzed on an intention-to-treat basis. The overall quality of the evidence supporting the primary and secondary outcomes was evaluated using the GRADE criteria.

MAIN RESULTS

Four placebo-controlled RCTs including 206 participants were included. Three trials included an 8 to 16 week induction phase with tapering corticosteroids (prednisone, prednisolone or methylprednisolone) as induction therapy. Anti-tuberculous therapy included monotherapy with clofazimine, combination therapy with clofazimine, rifampin, ethambutol, and dapsone or combination therapy with clarithromycin, rifabutin and clofazimine. All of the studies were rated as unclear risk of bias for allocation concealment, three were rated as unclear risk of bias for random sequence generation and two were rated as unclear risk of bias for blinding or participants and personnel. There was a statistically significant difference in relapse rates favoring anti-tuberculous therapy over placebo. Thirty-nine per cent (44/112) of patients in the anti-tuberculous therapy group relapsed at 9 months to 2 years compared to 67% (63/94) of placebo patients (RR 0.58, 95% CI 0.45 to 0.75, I(2) = 47%). A GRADE analysis indicates that the overall quality of the evidence supporting this outcome was very low due to unknown risk of bias and sparse data. Adverse events occurred more frequently in the anti-tuberculous therapy group (37/159) compared to the placebo group (14/163) with a pooled RR of 2.57 (95% CI 1.45 to 4.55; N=322; studies=4, I(2)=64%). A GRADE analysis indicates that the overall quality of the evidence supporting this outcome was very low due to unknown risk of bias, unexplained heterogeneity and sparse data. There was no difference in withdrawals due to adverse events. Nine per cent (14/159) of anti-tuberculous therapy patients withdrew due to adverse events compared to 7% (11/163) of placebo patients (RR 1.29, 95% CI 0.60 to 2.77, I(2) = 0%). Common adverse events included increased skin pigmentation and rashes. No serious adverse events were reported in any of the included studies.

AUTHORS' CONCLUSIONS

Anti-tuberculous therapy may provide a benefit over placebo for the prevention of relapse in participants with Crohn's disease in remission. However, this result is very uncertain due to unclear study quality and the small numbers of patients assessed. Further studies are needed to provide better quality evidence for the use of anti-tuberculous therapy for maintaining remission in people with quiescent Crohn's disease.

IBD and the gut microbiota--from bench to personalized medicine

Inflammatory bowel diseases (IBD) are chronic relapsing inflammatory disorders involving the gastrointestinal (GI) tract, which arise from the confluence of genetic, immunological, microbial, and environmental factors. Clinical, genetic, and experimental data support the role of gut microbiota in contributing to the etiopathogenesis of these diseases. In IBD, the development of gut dysbiosis and imbalances in host-microbe relationships contribute to the extent, severity, and chronicity of intestinal inflammation. With continued advances in knowledge, technology, bioinformatics tools, and capabilities to define disease subsets, we will be able to lower risk and improve clinical outcomes in IBD through individualized interventions that restore host-microbial balance. This article provides a critical review of the field, based on the latest clinical and experimental information.

The microbiota in inflammatory bowel disease

This review explores our current understanding of the complex interaction between environmental risk factors, genetic traits and the development of inflammatory bowel disease. The primacy of environmental risk factors is illustrated by the rapid increase in the incidence of the disease worldwide. We discuss how the gut microbiota is the proximate environmental risk factor for subsequent development of inflammatory bowel disease. The evolving fields of virome and mycobiome studies will further our understanding of the full potential of the gut microbiota in disease pathogenesis. Manipulating the gut microbiota is a promising therapeutic avenue.

Therapeutic Manipulation of the Microbiome in IBD: Current Results and Future Approaches

OPINION STATEMENT

Despite recent major strides in our understanding of the genetic and microbial influences that contribute to the development of the inflammatory bowel diseases (IBDs), their etiology continues to be enigmatic. Results from experiments in animal models of IBDs overwhelmingly support a causal role of the microbiota in these diseases, though whether such a cause-effect relationship exists in human IBDs is still uncertain. Therefore, virtually all currently approved and most often prescribed treatments for IBDs are directed toward the over-active immune response in these diseases rather than the intestinal bacteria. Nevertheless, there is an important need for non-immunosuppressive therapies that may present a more favorable risk-benefit profile such as those that selectively target the disruptions in gut microbiota that accompany IBDs. This need has led to clinical trials of various microbial-directed therapies including fecal microbial transplant, antibiotics, probiotics, and prebiotics. Unfortunately, these published studies, many of which are small, have generally failed to demonstrate a consistent benefit of these agents in IBDs, thus leading to slow acceptance of microbe-focused treatments for these conditions. In this article, we review and summarize the microbial basis for IBDs and the results of the most recent trials of fecal microbial transplant, antibiotics, probiotics, and prebiotics in IBDs. We also comment on possible safety concerns with these agents, speculate on why they have failed to show efficacy in certain clinical settings, and propose strategies to improve their usefulness.

Understanding host-adherent-invasive Escherichia coli interaction in Crohn's disease: opening up new therapeutic strategies

A trillion of microorganisms colonize the mammalian intestine. Most of them have coevolved with the host in a symbiotic relationship and some of them have developed strategies to promote their replication in the presence of competing microbiota. Recent evidence suggests that perturbation of the microbial community favors the emergence of opportunistic pathogens, in particular adherent-invasive Escherichia coli (AIEC) that can increase incidence and severity of gut inflammation in the context of Crohn's disease (CD). This review will report the importance of AIEC as triggers of intestinal inflammation, focusing on their impact on epithelial barrier function and stimulation of mucosal inflammation. Beyond manipulation of immune response, restoration of gut microbiota as a new treatment option for CD patients will be discussed.

Predictors of recurrence of Crohn’s disease after ileocolectomy: A review

Recurrence after ileocolectomy for Crohn’s disease (CD) is common and occurs in up to 80% of patients. Such recurrence can result in repeated surgical interventions, an increased need for medical treatment and, frequently, an impaired quality of life. The aim of this overview is to provide a summary of the factors associated with disease recurrence after ileocolectomy for CD. Recurrence can be measured clinically or endoscopically using established scoring systems. Radiology and serologic tests can also be used, oftentimes in conjunction with endoscopy and/or clinical findings. Many patient and operative factors as well as pharmacologic treatments have been studied as potential predictors of recurrence. Of these, only smoking and immunomodulatory or biologic medical treatment have repeatedly been shown to effect recurrence. Genetic predictors have been studied and suggested but further evaluation in larger cohorts is necessary. This paper highlights validated, reproducible scoring systems for recurrence and the key findings of studies including patient demographics, operative techniques, various pharmacological treatments and histological findings as predictors of recurrence post ileocolectomy in CD.

Azathioprine and 6-mercaptopurine for maintenance of surgically-induced remission in Crohn's disease

BACKGROUND

Crohn's disease (CD) is a chronic relapsing inflammatory condition. Many patients fail to achieve remission with medical management and require surgical interventions. Purine analogues have been used to maintain surgically-induced remission in CD, but the effectiveness of these agents is unclear.

OBJECTIVES

The objectives were to evaluate the efficacy and safety of purine analogues for maintenance of surgically-induced remission in CD.

SEARCH METHODS

We searched the following databases from inception to 30 April 2014: PubMed, MEDLINE, EMBASE, CENTRAL, and the Cochrane Inflammatory Bowel Disease and Functional Bowel Disorders Group Specialized Trials Register). We also searched the reference lists of all included studies, and contacted personal sources and drug companies to identify additional studies. The searches were not limited by language.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared purine analogues to placebo or another intervention, with treatment durations of at least six months were considered for inclusion. Participants were patients of any age with CD in remission following surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility and extracted data. Methodological quality was assessed using the Cochrane risk of bias tool. The primary outcome measures were clinical and endoscopic relapse as defined by the primary studies. Secondary outcomes included adverse events, withdrawal due to adverse events and serious adverse events. Data were analysed on an intention-to-treat basis where patients with missing final outcomes were assumed to have relapsed. We calculated the risk ratio (RR) and corresponding 95% confidence interval (95% CI) for dichotomous outcomes. The Chi(2) and I(2) statistics were used to assess heterogeneity. The overall quality of the evidence supporting the primary outcomes and selected secondary outcomes was assessed using the GRADE criteria.

MAIN RESULTS

Seven RCTs (n = 584 patients) were included in the review. Three studies compared azathioprine to 5-aminosalicylic acid (5-ASA). One small study compared azathioprine to both 5-ASA and adalimumab. One study compared azathioprine to placebo and another study compared 6-mercaptopurine to 5-ASA and placebo. One small study compared azathioprine to infliximab. Three studies were judged to be at low risk of bias. Four studies were judged to be at high risk of bias due to blinding. The study (n = 22) comparing azathioprine to infliximab found that the effects on the proportion of patients who had a clinical (RR 2.00, 95% CI 0.21 to 18.98) or endoscopic relapse (RR 4.40, 95% CI 0.59 to 3.07) were uncertain. One study (n = 33) found decreased clinical (RR 5.18, 95% CI 1.35 to 19.83) and endoscopic relapse (RR 10.35, 95% CI 1.50 to 71.32) rates favouring adalimumab over azathioprine. A pooled analysis of two studies (n = 168 patients) showed decreased clinical relapse rates at one or two years favouring purine analogues over placebo. Forty-eight per cent of patients in the purine analogue group experienced a clinical relapse compared to 63% of placebo patients (RR 0.74, 95% CI 0.58 to 0.94). A GRADE analysis indicated that the overall quality of the evidence supporting this outcome was low due to high risk of bias (one study was single-blind) and sparse data (93 events). One study (87 patients) found a reduction in endoscopic relapse rates favouring 6-mercaptopurine over placebo. Seventeen per cent of 6-mercaptopurine patients had an endoscopic relapse at two years compared to 42% of placebo patients (RR 0.40, 95% CI 0.19 to 0.83). A GRADE analysis indicated that the overall quality of the evidence for this outcome was low due to very sparse data (25 events). A pooled analysis of five studies (n = 425 patients) showed no difference in clinical relapse rates at one or two years between purine analogues and 5-ASA agents. Sixty-three per cent of patients in the purine analogues group experienced a clinical relapse compared to 54% of 5-ASA patients (RR 1.15, 95% CI 0.99 to 1.34). A GRADE analysis indicated that the overall quality of the evidence supporting this outcome was very low due to high risk of bias (two open-label studies), sparse data (249 events) and moderate heterogeneity (I(2) = 45%). There was no difference in endoscopic relapse at 12 months between azathioprine and 5-ASA (RR 0.78, 95% CI 0.52 to 1.17; 1 study, 35 patients). A GRADE analysis indicated that the overall quality of the evidence for this outcome was very low due to high risk of bias (open-label study) and very sparse data (26 events). There was a reduction in endoscopic relapse at 24 months favouring 6-mercaptopurine over 5-ASA patients. Seventeen per cent of 6-mercaptopurine patients had an endoscopic relapse compared to 48% of 5-ASA patients (RR 0.36, 95% CI 0.18 to 0.72; 1 study, 91 patients). A GRADE analysis indicated that the overall quality of the evidence for this outcome was low due to very sparse data (29 events). Adverse events that required withdrawal were more common in the purine analogue group compared to 5-ASA. Twenty per cent of patients in the purine analogue group withdrew due to adverse events compared to 10% of 5-ASA patients (RR 2.07, 95% CI 1.26 to 3.39; 5 studies, 423 patients).The results for withdrawal due to adverse events between purine analogues and placebo or for other comparisons were uncertain. Commonly reported adverse events across all studies included leucopenia, arthralgia, abdominal pain or severe epigastric intolerance, elevated liver enzymes, nausea and vomiting, pancreatitis, anaemia, exacerbation of Crohn's disease, nasopharyngitis, and flatulence.

AUTHORS' CONCLUSIONS

Purine analogues may be superior to placebo for maintenance of surgically-induced remission in patients with CD, although this is based on two small studies. The results for efficacy outcomes between purine analogues and 5-ASA agents were uncertain. However, patients taking purine analogues were more likely than 5-ASA patients to discontinue therapy due to adverse events. No firm conclusions can be drawn from the two small studies that compared azathioprine to infliximab or adalimumab. Adalimumab may be superior to azathioprine but further research is needed to confirm these results. Further research investigating the efficacy and safety of azathioprine and 6-mercaptopurine in comparison to other active medications in patients with surgically-induced remission of CD is warranted.