The efficacy of azathioprine and 6-mercaptopurine for the prevention of postoperative recurrence in patients with Crohn's disease remains uncertain

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.

Cytomegalovirus reactivation in inflammatory bowel disease: an uncommon occurrence related to corticosteroid dependence

Cytomegalovirus promotes mucosal injury in patients with inflammatory bowel disease, historically affecting 10-25% of ulcerative colitis patients with refractory disease. Viral reactivation is likely related to long-term corticosteroid therapy, which is no longer central to maintenance of patients with inflammatory bowel disease. We hypothesize that viral detection rates have decreased in the modern era, reflecting widespread use of immunomodulatory agents to control inflammation. We performed this study to evaluate the relationships between medical regimens and cytomegalovirus detection rates among patients with inflammatory bowel disease. We searched our database for all patients with established inflammatory bowel disease and severe flares diagnosed from 2002 to 2017. Patients maintained with corticosteroid therapy were considered to be corticosteroid-dependent and those treated with other agents were classified as corticosteroid-independent, provided they had not received corticosteroids within 6 months of colonoscopy. Biopsy samples were reviewed for viral inclusions and subjected to cytomegalovirus immunohistochemistry, and rates of viral detection were compared between groups. There were 135 corticosteroid-dependent patients; most had ulcerative colitis flares occurring during the 2002-2009 period. Patients with ulcerative colitis and Crohn disease were equally represented in the corticosteroid-independent group (n = 133) and most were evaluated for disease flares during the 2010-2017 interval. Cytomegalovirus was detected in 13 (8%) cases; 9 (69%) were diagnosed from 2002 to 2009 and all were obtained from corticosteroid-dependent patients (p = < 0.001). We conclude that rates of cytomegalovirus-related enterocolitis are declining among inflammatory bowel disease patients, reflecting a shift away from corticosteroid-based maintenance therapy in favor of more effective agents that do not promote viral reactivation.

Pediatric Crohn's Disease

The incidence of Crohn's disease in the pediatric population is increasing. While pediatric patients with Crohn's disease exhibit many of the characteristics of older patients, there are important differences in the clinical presentation and course of disease that can impact the clinical decisions made during treatment. The majority of children are diagnosed in the early teen years, but subgroups of very early onset and infantile Crohn's present much earlier and have a unique clinical course. Treatment paradigms follow the traditional laddered approach, but growth and development represent special considerations that must be given to pediatric-specific complications of the treatment and disease. Surgical intervention is an important component of Crohn's management and is often employed to allow improved nutritional intake or decrease reliance on medical treatments that compromise growth.

Trends in Pharmacologic Interventions for Preventing Recurrence of Crohn's Disease After Ileocolonic Surgery

BACKGROUND

Prophylactic treatment of postoperative Crohn's disease (CD) plays a critical role in maintaining clinical remission. We performed the first study in the last decade to examine secular trends in the use of pharmacologic interventions after ileocolonic resection in the United States, to understand whether clinical practice converges with recent advances in scientific knowledge.

METHODS

A retrospective study of a U.S. national claims database was performed. The study cohort included 106 CD patients in the years 1999 to 2001 (prebiologic era) and 294 CD patients in the years 2009 to 2011 (postbiologic era), who underwent ileocolonic resection. Medication use in the 12 months after the surgery was examined.

RESULTS

Significant variations in care were evident in both study periods. Across the 2 study periods, there was an increased use of biologics (from 0% to 36.4%) and a substantial reduction in the use of 5-aminosalicylic acid (from 50.9% to 28.2%; P < 0.0001). Therapeutic interventions that have been found ineffective in published studies continued to be widely applied: one-third of patients were prescribed corticosteroids, and several cases of prolonged use of corticosteroids or antibiotics were observed in both cohorts. Disease behavior (penetrating, stricturing, or nonpenetrating and nonstricturing) was not associated with the choice of postoperative therapeutic interventions, with the exception of an increased use of antibiotics among patients with penetrating disease.

CONCLUSIONS

There is a substantial gap between advances in postoperative care for ileocolonic CD and clinical practice. Strategies to expedite the integration of new knowledge and evidence into practice are urgently needed.

Tripterygium wilfordii Hook. f. versus azathioprine for prevention of postoperative recurrence in patients with Crohn's disease: a randomized clinical trial

BACKGROUND

Tripterygium wilfordii Hook. f. (TwHF) has been used for many years to induce the remission of Crohn's disease in China.

AIMS

To compare TwHF versus azathioprine for the prevention of postoperative recurrence in Crohn's disease.

METHODS

90 Crohn's disease patients who had undergone resection were treated with TwHF 1.5mg/kg/day or azathioprine 2.0 mg/kg/day. The primary endpoint was clinical recurrence, and the secondary endpoint was endoscopic recurrence.

RESULTS

47 patients completed the trial. Clinical recurrence was observed in 6/45 patients in the TwHF group and 4/45 patients in the azathioprine group at week 26 (P=0.74). At week 52, 8/45 azathioprine patients and 12/45 TwHF patients had clinical recurrence (P = 0.45). During the first 26 weeks, 56.8% of the patients in the TwHF group versus 47.7% in the azathioprine group experienced endoscopic recurrence (P = 0.52). However, at week 52, 74.4% of patients in the TwHF group and 50% in the azathioprine group had endoscopic recurrence (P = 0.03).

CONCLUSIONS

TwHF was less effective in maintaining endoscopic remission at week 52, even though TwHF was comparable to azathioprine for preventing postoperative clinical recurrence.

Preliminary results of the influence of the in vivo use of a lymphatic dye (patent blue v) in the surgical treatment of Crohn's disease

INTRODUCTION

Recently, the lymphatic vessels has been considered to play a key role in the pathophysiology and, consequently, in the treatment of Crohn's disease (CD). The aim of this study is to show that the evaluation of lymphatic anomaly might be a useful tool in the recognition of the pathological involvement of the intestinal wall in CD.

MATERIAL AND METHODS

Fourteen patients with CD who underwent surgical treatment for distal ileum critical stenosis were prospectively evaluated. During surgery, 0.05 to 0.1 mL of Patent Blue V was injected into the subserosal layer of the antimesenteric edge of ileum and colon. The intestinal section was performed just beneath the outflow of the vital dye where it seemed to be normal (≤2 minutes), as a index of healthy intestinal wall. A comparison between the lymphatic alterations and the macroscopic aspects was performed.

RESULTS

Out of 14 patients, 13 were electively operated on, whereas 1 was treated in emergency. In 8 patients (57%), laparoscopic approach was chosen in the first instance. One patient needed laparotomic conversion. When comparing the Patent Blue V outflow time with the macroscopic and microscopic evidence of CD, we found an absolute integrity of the intestinal wall with an outflow ≤2 minutes. Mean follow-up was 110 months with a recurrence rate of 14%.

CONCLUSION

We can conclude that this method may be of utility to distinguish between normal and diseased intestine in CD. The possible consequences in postsurgical recurrences of this evidence are critical.

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

BACKGROUND

Endoscopic recurrence occurs in up to 80% of patients with Crohn's disease 1 year after intestinal resection. Imidazole antibiotics, thiopurines, and particularly their combination have proven efficacy in preventing endoscopic recurrence. The aim of the study was to compare the efficacy of the addition of metronidazole (for 3 months after the surgical treatment) to azathioprine for the prevention of postsurgical endoscopic recurrence.

METHODS

A pilot study was made of 50 patients with Crohn's disease undergoing intestinal resection with ileocolic anastomosis and treated with 2 to 2.5 mg/kg of azathioprine per day for 1 year. The patients were randomized to receive additional 15 to 20 mg/kg of metronidazole per day or placebo for the first 3 months (n = 25 per arm). Endoscopic assessment was performed 6 and 12 months after the surgical resection. The primary end point was the prevention of endoscopic recurrence as defined by a Rutgeerts score of <2 at 6 months. The initial sample size had an 80% statistical power in detecting an absolute risk reduction of ≥30%.

RESULTS

Endoscopic recurrence occurred in 28% and 44% of the patients at 6 months (P = 0.19) and in 36% and 56% (P = 0.15) at 12 months in the metronidazole and placebo groups, respectively. No statistically significant differences were found between the treatment groups regarding severe endoscopic recurrence (Rutgeerts score ≥ 3) at 6 and 12 months. Likewise, there were no differences in the rate of adverse events between the treatment groups.

CONCLUSIONS

The addition of metronidazole to azathioprine did not significantly reduce the risk of endoscopic recurrence beyond azathioprine alone in this study but does not worsen its safety profile.

State-of-the-art medical prevention of postoperative recurrence of Crohn's disease

Postoperative recurrence of Crohn's disease is a frequent and often severe sequela of the disease. Until a few years ago it was deemed inescapable, as all the conventional medications used to treat the disease have been proven of little benefit in preventing recurrence after surgical treatment. In the past few years, anti-TNF agents given immediately after surgery have shown a remarkable efficacy in the prevention of disease recurrence. Large, randomized, controlled trials are currently underway to confirm these findings. Anti-TNF treatment of endoscopic lesions that occur after surgery seems to be less effective than using TNF antagonists to prevent recurrence. However, although the data are limited, this treatment strategy seems to be still superior to all the other prevention strategies that are not based on anti-TNF agents. Limited data are available on long-term outcomes of patients treated with anti-TNF agents after surgery. They suggest that these medications are safe and effective after many years of treatment. In addition, these agents might prevent recurrence even at doses lower than those used in patients with Crohn's disease who have not had surgery.

Impact of postoperative infliximab maintenance therapy on preventing the surgical recurrence of Crohn's disease: a single-center paired case-control study

PURPOSE

Preventing a recurrence of Crohn's disease is a problem that remains to be solved. We evaluated the impact of using infliximab as a postoperative therapy on preventing the surgical recurrence of Crohn's disease.

METHODS

We performed a pair-matched study comparing 100 patients who had received postoperative infliximab maintenance therapy with those who had not between 1995 and 2010. The patients were matched by gender, Vienna classification and age at the time of the operation. Crohn's disease-related reoperation was evaluated as surgical recurrence.

RESULTS

In the postoperative infliximab maintenance therapy group, infliximab was administrated within 8 weeks after the operation. The median follow-up period was 36 months in the postoperative infliximab maintenance therapy group and 51 months in the control group. Surgical recurrences were recognized in 37 patients (three in the postoperative infliximab maintenance therapy group and 34 in the control group). A univariate analysis by the Kaplan-Meier method identified a body mass index >18 at the time of the operation (HR 0.19, p = 0.01) and postoperative infliximab maintenance therapy (HR 0.22, p = 0.0022) as factors related to the reduction of surgical recurrence. The multivariate analysis revealed that postoperative infliximab maintenance therapy was the only significant factor preventing surgical recurrence.

CONCLUSION

Postoperative infliximab maintenance therapy for Crohn's disease prevents surgical recurrence, at least within 3 years after the operation.

The evolving management of postoperative Crohn's disease

Two-thirds to three-quarters of Crohn's disease patients require intestinal surgery for medically refractory disease or complications. Surgery is not a cure and most patients develop recurrent Crohn's disease and require additional intestinal resections. There are a number of medications that have been investigated for preventing and treating recurrence. Risk factors for postoperative disease recurrence help guide the physician in determining the appropriate treatment strategy after Crohn's disease surgery. The approach to Crohn's disease treatment has evolved over the years. No longer should surgery be considered a failure of treatment, rather an important intervention to correct irreversible disease. In combination with a better understanding of postoperative medication strategies, patients with Crohn's disease may achieve longer term remission than previously realized. This review elucidates current understanding of the natural course of postoperative Crohn's disease, monitoring for recurrence, the risk factors for recurrence, and provides insight into an evolving new paradigm for postoperative Crohn's disease treatment.

Prevention of postoperative recurrence of Crohn's disease by Adalimumab: a case series

Adalimumab, an anti-TNF-α monoclonal antibody, was found to be effective for the treatment of luminal Crohn's disease (CD), but its efficacy for the prevention of postoperative recurrence of CD is still unknown. Here, we present a case series of six patients who underwent resection for an ileocecal stricture caused by CD. Surgery removed the involved ileocolon, and pathology confirmed the presence of a fibrotic stricture. Two weeks after the operation, they were given Adalimumab at the dose of 160/80/40 mg every 2 weeks and were followed up. Since then, they have been disease-free for ≈ 3 years after surgery on clinical, radiological, and endoscopic/histological grounds (Crohn's Disease Activity Index ≤ 110 in all occasions). Up to now, they have had no anemia, no increase in inflammatory indices, and no abnormal blood tests. These are the first cases, to our knowledge, in which Adalimumab has been successfully used to prevent the postsurgical recurrence of CD, an event so far considered to be mandatory. Further large placebo-controlled studies are necessary to show the therapeutic advantage and the economic implications of these observations.

Predicting, treating and preventing postoperative recurrence of Crohn's disease: the state of the field

The majority of patients diagnosed with Crohn's disease eventually require surgical intervention. Unfortunately, postsurgical remission tends to be short lived; a significant number of patients experience clinical relapse and many require additional operations. The pathogenesis of this postoperative recurrence is poorly understood and, currently, there are no reliable tools to predict when and in whom the disease will recur. Furthermore, the postoperative prophylaxis profiles of available Crohn's disease therapeutic agents such as 5-aminosalicylates, immunomodulators, steroids and probiotics have been disappointing. Recently, the combination of antibiotics and azathioprine in selected high-risk patients has demonstrated some potential for benefit. The goal of the present article is to provide a coherent summary of previous and new research to guide clinicians in managing the challenging and complex problem of postoperative Crohn's disease recurrence.

Is the length of postoperative recurrence on the neo ileum terminal ileum predictable in Crohn's disease?

Crohn's disease (CD) often has a stricturing phenotype on the terminal ileum requiring surgery due to obstruction. Recurrence is frequent, creating a risk of multiple surgeries. We studied patients with ileal or ileo-colic CD who had undergone at least two surgical bowel resections between 1968 and 2008 for obstructive symptoms.

AIMS

The aim of this retrospective study was to determine if the length of the removed diseased bowel varied from one surgical resection to the next. The measurements obtained from radiology (small bowel follow-up), surgery and histology were compared.

RESULTS

Twenty four patients were included. Seventeen had 2 resections, 5 patients had 3 resections and two had 4 resections. The resected length of the diseased ileum was significantly shorter for the second intervention than for the first as assessed by radiology (median 16 cm vs 37 cm; p=0.0005), surgery (20 cm vs 40 cm; p=0.005) and histology (15 cm vs 25 cm; p=0.02) while there was no difference between the second and third resections (16 cm, 13 cm, 19.5 cm respectively) for the three types of measurements (p=NS). The surgeon's assessment of the diseased segment was longer than the histologist's (p=0.003). No factor was found to be significantly associated with the length of the diseased bowel on recurrence.

CONCLUSION

This study shows that the length of the excised neo-terminal ileum during the first episode of recurrence was shorter than during the first episode of disease and remained stable for the third episode. This is an important prognostic finding that could influence the therapeutic choices for this disease and reduce hesitation to indicate surgery.

Low-dose maintenance therapy with infliximab prevents postsurgical recurrence of Crohn's disease

BACKGROUND & AIMS

Infliximab might prevent postsurgical recurrence of Crohn's disease. However, it is unclear whether long-term therapy is necessary and whether alternative strategies could be applied to minimize potential side effects and reduce the costs of treatment.

METHODS

We performed a prospective cohort study in 12 consecutive patients, treated immediately after surgery with maintenance infliximab (5 mg/kg), who did not have clinical or endoscopic evidence of disease recurrence after 24 months; they were followed up for an additional year. Infliximab treatment was then discontinued; patients with disease recurrence, based on endoscopy (Rutgeerts score, >or=2), were given lower doses of infliximab (starting with 1 mg/kg) to re-establish mucosal integrity. Surrogate markers of disease activity (fecal calprotectin [FC], C-reactive protein, and erythrocyte sedimentation rate) were assessed after each infliximab dose.

RESULTS

None of the patients had clinical or endoscopic recurrence of Crohn's disease 3 years after surgery. However, discontinuation of infliximab caused endoscopic recurrence after 4 months in 10 of 12 patients (83%). All 10 patients then were treated again with infliximab, which, at a dose of 3 mg/kg every 8 weeks, restored and maintained mucosal integrity for 1 year. Among the surrogate markers, FC levels correlated with endoscopic scores (Wald test, P < .0001).

CONCLUSIONS

Long-term maintenance therapy with infliximab is required to maintain mucosal integrity in patients after surgery for Crohn's disease. However, a dose of 3 mg/kg (a 40% reduction from the standard dose) was sufficient to avoid disease recurrence, determined by endoscopy, in all patients at 1 year. FC levels correlate with mucosal status at different infliximab doses.

Interventions for prevention of post-operative recurrence of Crohn's disease

BACKGROUND

Recurrence of Crohn's disease is common after intestinal resection. A number of agents have been studied in controlled trials with the goal of reducing the risk of endoscopic or clinical recurrence of Crohn's disease following surgery.

OBJECTIVES

To undertake a systematic review of the use of medical therapies for the prevention of post-operative recurrence of Crohn's disease

SEARCH STRATEGY

MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched to identify relevant studies. References from selected papers and abstracts from Digestive Disease Week were also searched.

SELECTION CRITERIA

Randomised controlled trials that compared medical therapy to placebo or other medical agents for the prevention of recurrence of intestinal Crohn's disease were selected for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors reviewed all abstracts containing search terms, and those meeting inclusion criteria were selected for full data abstraction. Dichotomous data were summarised using relative risk and 95% confidence intervals. A fixed-effects model was used, and sensitivity analysis performed.

MAIN RESULTS

Twenty-three studies were identified for inclusion. Probiotics were not superior to placebo for any outcome measured. The use of nitroimidazole antibiotics appeared to reduce the risk of clinical (RR 0.23; 95%CI 0.09 to 0.57, NNT=4) and endoscopic (RR 0.44; 95%CI 0.26 to 0.74, NNT = 4) recurrence relative to placebo. However, these agents were associated with higher risk of serious adverse events (RR 2.39, 95% CI 1.5 to 3.7). Mesalamine therapy was associated with a significantly reduced risk of clinical recurrence (RR 0.76; 95% CI 0.62 to 0.94, NNT = 12), and severe endoscopic recurrence (RR 0.50; 95% CI 0.29 to 0.84, NNT = 8) when compared to placebo. Azathioprine/6MP was also associated with a significantly reduced risk of clinical recurrence (RR 0.59; 95% CI 0.38 to 0.92, NNT = 7), and severe endoscopic recurrence (RR 0.64; 95% CI 0.44 to 0.92, NNT = 4), when compared to placebo. Neither agent had a higher risk than placebo of serious adverse events. When compared to azathioprine/6MP, mesalamine was associated with a higher risk of any endoscopic recurrence (RR 1.45, 95% CI 1.03 to 2.06), but a lower risk of serious adverse events (RR 0.51; 95% CI 0.30 to 0.89). There was no significant difference between mesalamine and azathioprine/6MP for any other outcome.

AUTHORS' CONCLUSIONS

There are insufficient randomised controlled trials of infliximab, budesonide, tenovil and interleukin-10 to draw conclusions. Nitro-imidazole antibiotics, mesalamine and immunosuppressive therapy with azathioprine/6-MP or infliximab all appear to be superior to placebo for the prevention of post-operative recurrence of Crohn's disease. The cost, toxicity and tolerability of these approaches require careful consideration to determine the optimal approach for post-operative prophylaxis.

Azathioprine and 6-mercaptopurine for the prevention of postoperative recurrence in Crohn's disease: a meta-analysis

OBJECTIVES

To evaluate the efficacy and safety of purine analogs (azathioprine, 6-mercaptopurine (6-MP)) in the prevention of postoperative recurrence in Crohn's disease (CD).

METHODS

We searched MEDLINE, the Cochrane Library, and EMBASE. The primary end points, clinical and endoscopic recurrence at 1 and 2 years, and safety were analyzed by the methods of Peto and Der Simonian and Laird.

RESULTS

Four controlled trials enrolled 433 patients and compared azathioprine (n=3) or (6-MP) (n=1) with control arms (placebo with or without antibiotic induction therapy or mesalamine). In the overall analysis, purine analogs were more effective than control arms in preventing clinical recurrence at 1 year (mean difference, 95% confidence interval (CI): 8, 1-15%, P=0.021, number needed to treat (NNT)=13) and 2 years (mean difference, 95% CI: 13%, 2-24%, P=0.018, NNT=8). In sensitivity analyses, the efficacy of purine analogs was superior to that of placebo for the prevention of clinical and endoscopic recurrence at 1 year (mean differences, 95% CI: 13, 1.8-25%, P=0.025, NNT=7, and 23%, 9-37%, P=0.0016, NNT=4, respectively). At 1 year, in the overall analysis, purine analogs were more effective than control arms were in preventing severe (i2-4) endoscopic recurrence (mean difference, CI 95%: 15, 1.8-29%, P=0.026, NNT=7), but they were not effective in the prevention of very severe (i3-4) recurrence. The rate of adverse events leading to drug withdrawal was higher in thiopurine-treated patients than in control arms (17.2 vs. 9.8%, respectively, P=0.021).

CONCLUSIONS

Purine analogs are more effective than placebo in preventing both clinical and endoscopic postoperative recurrence in CD, but they are associated with a higher rate of adverse events leading to drug withdrawal.

Postoperative Crohn's disease: prevention and treatment

Crohn's disease is a chronic, relapsing-remitting inflammatory disease of the intestinal tract that commonly requires surgical treatment. Unfortunately, the majority of patients will ultimately develop postoperative disease recurrence and require subsequent surgery. A number of medications have been researched for the maintenance of postoperative remission. Of these, few have demonstrated consistent efficacy. A recently published randomized, controlled trial indicated that infliximab is effective in the maintenance of postoperative remission.

Postoperative therapy for Crohn's disease

Prevention of the postoperative recurrence of Crohn's disease (CD) remains a challenging clinical problem. The majority of patients with CD will need surgery for treatment of the disease, most of these patients will develop recurrent symptoms within 5 years postoperatively, and many patients will need reoperation within 10 years. In patients with an ileocolic anastomosis, endoscopic recurrence precedes clinical recurrence and the severity of endoscopic recurrence correlates with the risk of clinical recurrence. Despite multiple studies, the best postoperative prophylactic therapy remains uncertain. Numerous randomized controlled trials of 5-aminosalicylates have shown only modest effect. Antibiotics, including metronidazole and ornidazole, decrease short-term, but not long-term endoscopic recurrence and are limited by side effects. Immunomodulators have yet to be extensively evaluated, although limited data suggest possible efficacy in preventing postoperative recurrence, particularly in high-risk patients. This review will evaluate the current state of the art therapy for postoperative prophylaxis in CD, with an emphasis on critical analysis of the available randomized controlled trials.

Management of Crohn's disease in adults

Guidelines for clinical practice are intended to suggest preferable approaches to particular medical problems as established by interpretation and collation of scientifically valid research, derived from extensive review of published literature. When data that will withstand objective scrutiny are not available, a recommendation may be made based on a consensus of experts. Guidelines are intended to apply to the clinical situation for all physicians without regard to specialty. Guidelines are intended to be flexible, not necessarily indicating the only acceptable approach, and should be distinguished from standards of care that are inflexible and rarely violated. Given the wide range of choices in any health-care problem, the physician should select the course best suited to the individual patient and the clinical situation presented. These guidelines are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee. Expert opinion is solicited from the outset for the document. The quality of evidence upon which a specific recommendation is based is as follows: Grade A: Homogeneous evidence from multiple well-designed randomized (therapeutic) or cohort (descriptive) controlled trials, each involving a number of participants to be of sufficient statistical power. Grade B: Evidence from at least one large well-designed clinical trial with or without randomization, from cohort or case-control analytic studies, or well-designed meta-analysis. Grade C: Evidence based on clinical experience, descriptive studies, or reports of expert committees. The Committee reviews guidelines in depth, with participation from experienced clinicians and others in related fields. The final recommendations are based on the data available at the time of the production of the document and may be updated with pertinent scientific developments at a later time.

Matrix metalloproteinases and their tissue inhibitors as prognostic indicators for diagnostic and surgical recurrence in Crohn's disease

BACKGROUND

Recurrence of disease after surgically induced remission constitutes a major and largely unpredictable problem in Crohn's disease (CD). Matrix metalloproteinases (MMP) and the tissue inhibitors of metalloproteinases (TIMP) are involved in the (etio)pathogenesis of CD and may thereby also affect postsurgical outcome. We studied the predictive value of 1) allelic composition at MMP, TIMP, and TNF-alpha single nucleotide polymorphism loci, and 2) MMP and TIMP intestinal protein levels relative to important clinical variables for recurrence of CD after resection of diseased bowel.

METHODS

From 87 CD patients with a full medical record, surgically resected tissue was homogenized and analyzed for single nucleotide polymorphism (SNP) genotype and MMP-TIMP protein levels. The prognostic value of these parameters was determined using the uni- and multivariate Cox proportional hazards analyses.

RESULTS

The T allele at TIMP-1 SNP +372 T/C was found to be associated with an increased risk for surgical recurrence. Higher levels of TIMP-1, TIMP-2, and MMP-9 in noninflamed CD tissue, but not in inflamed tissue, and negative smoking status independently protected against diagnostic and/or surgical recurrence.

CONCLUSIONS

The TIMP-1 SNP +372 T allele with an increased risk of recurrence is in line with our previous results demonstrating increased CD susceptibility and low TIMP-1 protein expression associated with this allele. High TIMP and MMP-9 levels in noninflamed tissue are predictive of a favorable disease recurrence in CD. The contribution of MMP-9 and TIMPs to disease recurrence appears not to be mediated by smoking status, since no correlation with this parameter could be demonstrated.

Infliximab in Crohn's disease: a look at the (not so distant) future

Although infliximab has brought about a major advance in the treatment of Crohn's disease (CD), several questions remain unanswered. In particular, there is no consensus regarding the best timing to use it in the ideal therapeutic algorithm. Another controversial issue is whether this medication should be given or not for life once proven effective in the individual patient. Therapy with infliximab has also been associated to the development of intestinal strictures in CD: hence, some authors have discouraged its use in their presence. Finally, given its powerful antiinflammatory action, infliximab could in theory be effective in preventing postsurgical recurrence of CD, an as yet almost inescapable consequence of "curative" surgery. This review will focus on and discuss the relevant recent literature related to these issues with special regard to the efficacy and safety of infliximab in the presence of intestinal strictures and the potential role of this medication in preventing recurrence after surgery.

Early symptomatic recurrence after intestinal resection in Crohn's disease is unpredictable

OBJECTIVE

To identify predictors of early symptomatic recurrence of Crohn's disease (CD) after surgical resection.

METHOD

We studied a cohort of 128 patients who had undergone at least one intestinal resection for CD. Factors that might predict early recurrence were documented for analysis using a standardized pro forma. These comprised age, gender, family history, extra-intestinal manifestations, smoking, complicated disease at first presentation, site of disease, preoperative inflammatory markers, involvement of resection margins, orientation and method of anastomosis and postoperative medical therapy. All symptomatic recurrences were confirmed by endoscopic, radiological, or operative means. We defined early recurrence as that which occurred within 36 months of first surgery. Univariate analysis was conducted to compare the distribution of each factor in those who developed early recurrence (n = 48) and those who remained disease free for the first 36 months (n = 50).

RESULTS

Of the 128 patients studied, 98 fulfilled the inclusion criteria of at least 36 months of follow up. Of these patients, 48 (49%) patients developed recurrence. Trends towards fewer early recurrences were seen in patients with colonic disease (33%vs 56%, P = 0.068). Of the current smokers, 60% developed early recurrence compared with 43% of nonsmokers (P = 0.269). All other factors examined were similarly distributed between the two groups. Metronidazole as adjuvant treatment does not appear to protect against early symptomatic recurrence.

CONCLUSION

This study shows that early symptomatic postoperative recurrence of CD remains unpredictable. Against expectation, abstinence from smoking and postoperative adjuvant metronidazole did not appear to protect against early symptomatic recurrence.

Drug insight: aminosalicylates for the treatment of IBD

Sulfasalazine and mesalazine (also known as mesalamine; 5-aminosalicylic acid) preparations have for many years been used for the treatment of IBD (i.e. ulcerative colitis and Crohn's disease), for both active disease and the control of remission. It has also been suggested that mesalazine is a chemoprophylactic agent that protects against the development of colorectal cancer. This Review focuses on the latest clinical evidence for the use of these aminosalicylates for the treatment of IBD, and concludes that sulfasalazine and mesalazine are useful for the treatment of both active and quiescent ulcerative colitis, whereas they have no clinical effect on either active or inactive Crohn's disease. Furthermore, evidence is lacking that mesalazine per se is a chemoprophylactic agent.

Review article: can post-operative recurrence in Crohn's disease be prevented?

The decision regarding prophylactic treatment after surgery in Crohn's disease (CD) requires a good estimation of the risk of recurrence. It is also important to consider the consequences of recurrence for the patient, and the risks and benefits of treatment, bearing in mind that it will be given over a long period. Several drugs have been tried to decrease the risk of recurrence. Corticosteroids and budesonide have proved to be ineffective. Mesalazine has significant efficacy in some, but not all trials, and a meta-analysis has established that it decreases the absolute risk by 10-15% after 1-2 years. Mercaptopurine seemed to be effective in a recent study. Metronidazole and ornidazole have significant efficacy, but cannot be tolerated for long periods. Probiotics represent a new approach, but evidence for their efficacy in CD is still lacking. In the past, the strategy was to give no treatment until clinical recurrence. Another approach is to give no treatment, and then to treat the patient according to severity of endoscopic recurrence. Alternative strategies include treating all patients with mesalazine until either severe endoscopic or clinical recurrence occurs, and then to use azathioprine/mercaptopurine, or to give azathioprine/mercaptopurine immediately, especially in high-risk patients.

Review article: thiopurines in inflammatory bowel disease

BACKGROUND

In the past 10-20 years, knowledge of both thiopurine pharmacology and -pharmacogenetics has been extended dramatically and used to develop new strategies to improve efficacy and reduce toxicity.

AIM

To review thiopurine efficacy, toxicity, pharmacology, pharmacogenetics, interactions in patients with inflammatory bowel disease. Special attention was paid to new strategies for optimization of pharmacotherapy.

METHODS

To collect relevant scientific articles, a Pubmed search was performed from 1966 through January 2006 with the following key words (MeSH terms preferentially) in multiple combinations: 'azathioprine', '6-mercaptopurine', '6-MP', '6-thioguanine', '6-TG', 'thiopurine(s)', 'metabolites', 'level(s)', 'TDM', 'TMPT', 'ITPA', 'genotype(s)', 'phenotype(s)', 'inflammatory bowel disease', 'Crohn('s) disease', 'ulcerative colitis'.

RESULTS

Strategies for optimization of pharmacotherapy include therapeutic drug monitoring of thiopurine metabolites, geno- or phenotyping crucial enzymes in thiopurine metabolism like thiopurine S-methyltransferase and inosine triphosphate pyrophosphatase, and the use of thioguanine as such.

CONCLUSIONS

Thiopurine S-methyltransferase genotyping and therapeutic drug monitoring are useful instruments for individualizing thiopurine pharmacotherapy of inflammatory bowel disease. Inosine triphosphate pyrophosphatase genotyping may be helpful in case of unexplainable myelotoxicity. In case of azathioprine- or mercaptopurine-intolerance, thioguanine seems a promising alternative. However, more knowledge needs to be gathered about its potential hepatotoxicity.

Prevention of postoperative recurrence of Crohn's disease by infliximab

The prevention of the recurrence of Crohn's disease after surgery remains difficult. The monoclonal antibody anti-TNF-alpha, infliximab, is very effective in inducing and maintaining the remission of uncomplicated, active Crohn's disease. We present here the case of a 23-year-old white woman who underwent resection for a sigmoid stricture caused by Crohn's disease. Surgery removed the involved colon, and pathology confirmed the stricture to be fibrotic. Two weeks after the operation she was given infliximab at the dose of 5 mg/kg body weight and followed in time. Since then, she has been disease free for approximately 4 years after surgery on clinical, radiological and endoscopic/histological grounds (Crohn's Disease Activity Index < or = 110 on all occasions). Up to now, she has had no increase in inflammatory indices, no anaemia and no abnormal blood tests. In contrast, all of five control patients operated in the same period with colonic or ileocolonic resection for symptomatic strictures and treated with mesalamine or no medication developed endoscopic or clinical recurrence (abdominal pain or diarrhoea) by year 3. This is the first case, to our knowledge, in which infliximab has been successfully used to prevent the postsurgical recurrence of Crohn's disease, an event so far considered to be inescapable. We believe that, with this aim in mind, clinical trials with this drug are warranted.

Surgical management of Crohn's disease in children

One of the most common beliefs in the management of Crohn's disease is that surgery should be considered only as a last resort. Surgery is often considered by patients and gastroenterologists to represent a "failure." However, the role of surgery in the care of patients with Crohn's disease has increasingly become a collaborative effort, with surgeons involved in many aspects of the management of these patients. This is particularly true in pediatric patients, as issues of growth and development may involve surgical intervention at earlier stages than might be required in older patients. In fact, surgical interventions may be indicated at any stage of the disease process. For example, early examination under anesthesia with abscess drainage and delineation of fistula tracts has proven very useful in patients with complex perineal disease. Surgery may contribute to the medical management of the disease by way of providing chronic enteral or parenteral access for nutritional interventions such as elemental feedings and total parenteral nutrition. Finally, surgical treatment of intra-abdominal complications including fistulas, phlegmon, and bowel strictures may have a dramatic impact on patient symptoms and side effects. Although bowel resection carries the long-term risk of short bowel syndrome should future resections be required, the improvements in medical therapy continue to reduce the risk of recurrent disease, making surgical resection more palatable. Surgical treatment of complicated disease offers significant potential to limit toxic medical therapy and improve quality of life. In addition, application of minimally invasive techniques can minimize the impact of insults to body image in this vulnerable patient population as well as speed recovery. Future interventions may be facilitated by reducing adhesion formation through the use of minimally invasive techniques. The dynamic nature of growth and development in the pediatric population presents unique complications from medical therapies that are different from those seen in adults. Criteria for surgical intervention must be interpreted in light of the specific challenges facing the pediatric population as frequently pointed out in the oft-quoted maxim, "children are not small adults!"

Postoperative Crohn's disease

More than three quarters of patients with Crohn's disease (CD) will require surgery. After resection, disease recurs postoperatively with a median time to second resection of about 10 years. Despite its importance, the postoperative period remains one of the most poorly understood clinical settings in the field. Postoperatively, CD may exhibit unique pathophysiologic features, but the current state of knowledge does not allow for identification of patients at risk for relapse, and leaves clinicians without guidance on optimal maintenance treatment. Therapies used as maintenance for CD in other settings may have different efficacies when used after surgery, and clinical research in patients requiring surgery is limited by the subset of patients available for study. Despite the many limitations in current knowledge of postoperative CD, it is an exciting field because new developments have improved patient care, and ongoing research has the potential for further gains.