Natural Disease Course of Ulcerative Colitis During the First Five Years of Follow-up in a European Population-based Inception Cohort-An Epi-IBD Study

BACKGROUND AND AIMS

Few population-based cohort studies have assessed the disease course of ulcerative colitis [UC] in the era of biological therapy and widespread use of immunomodulators. The aim of this study was to assess the 5-year outcome and disease course of patients with UC in the Epi-IBD cohort.

METHODS

In a prospective, population-based inception cohort of unselected patients with UC, patients were followed up from the time of their diagnosis, which included the collection of their clinical data, demographics, disease activity, medical therapy, and rates of surgery, cancers, and deaths. Associations between outcomes and multiple covariates were analysed by Cox regression analysis.

RESULTS

A total of 717 patients were included in the study. During follow-up, 43 [6%] patients underwent a colectomy and 163 [23%] patients were hospitalised. Of patients with limited colitis [distal to the left flexure], 90 [21%] progressed to extensive colitis. In addition, 92 [27%] patients with extensive colitis experienced a regression in disease extent, which was associated with a reduced risk of hospitalisation (hazard ratio [HR]: 0.5 95% CI: 0.3-0.8]. Overall, patients were treated similarly in both geographical regions; 80 [11%] patients needed biological therapy and 210 [29%] patients received immunomodulators. Treatment with immunomodulators was found to reduce the risk of hospitalisation [HR: 0.5 95% CI: 0.3-0.8].

CONCLUSIONS

Although patients in this population-based cohort were treated more aggressively with immunomodulators and biological therapy than in cohorts from the previous two decades, their disease outcomes, including colectomy rates, were no different. However, treatment with immunomodulators was found to reduce the risk of hospitalisation.

Developing a core outcome set for fistulising perianal Crohn's disease

OBJECTIVE

Lack of standardised outcomes hampers effective analysis and comparison of data when comparing treatments in fistulising perianal Crohn's disease (pCD). Development of a standardised set of outcomes would resolve these issues. This study provides the definitive core outcome set (COS) for fistulising pCD.

DESIGN

Candidate outcomes were generated through a systematic review and patient interviews. Consensus was established via a three-round Delphi process using a 9-point Likert scale based on how important they felt it was in determining treatment success culminating in a final consensus meeting. Stakeholders were recruited nationally and grouped into three panels (surgeons and radiologists, gastroenterologists and IBD specialist nurses, and patients). Participants received feedback from their panel (in the second round) and all participants (in the third round) to allow refinement of their scores.

RESULTS

A total of 295 outcomes were identified from systematic reviews and interviews that were categorised into 92 domains. 187 stakeholders (response rate 78.5%) prioritised 49 outcomes through a three-round Delphi study. The final consensus meeting of 41 experts and patients generated agreement on an eight domain COS. The COS comprised three patient-reported outcome domains (quality of life, incontinence and a combined score of patient priorities) and five clinician-reported outcome domains (perianal disease activity, development of new perianal abscess/sepsis, new/recurrent fistula, unplanned surgery and faecal diversion).

CONCLUSION

A fistulising pCD COS has been produced by all key stakeholders. Application of the COS will reduce heterogeneity in outcome reporting, thereby facilitating more meaningful comparisons between treatments, data synthesis and ultimately benefit patient care.

Practical guidance for the management of inflammatory bowel disease in patients with cancer. Which treatment?

Clinicians involved in the treatment of inflammatory bowel disease (IBD) increasingly come across patients with current or previous history of malignancies. With increasing and earlier use of immunosuppression and biologics in IBD patients, the question arises whether these treatments further increase the risk of new or recurrent cancers. A number of population-based observational studies have now reported the odds of development of new or recurrent cancers with thiopurines and antitumour necrosis factors (anti-TNFs). These data combined with data arising from treatment registries from other immune disorders such as rheumatoid arthritis are providing evidence of relative risks and safety profiles of these agents in the setting of active or prior cancer. Data from transplant literature give an indication for providing a drug-holiday period in patients with treated cancers. The risks of the treatment should be considered alongside the risk associated with withholding these effective treatments in patients with active IBD. In this review, we aim to summarize the current evidence in this area and provide a practical guidance.

The role of multimodal treatment in Crohn's disease patients with perianal fistula: a multicentre retrospective cohort study

BACKGROUND

Treatment paradigms for Crohn's disease with perianal fistulae (CD-pAF) are evolving.

AIMS

To study the impact of multimodality treatment in CD-pAF on recurrence rates and the need for re-interventions and to identify predictive factors for these outcomes.

METHODS

This was a multinational multicentre retrospective cohort study. Multimodality approach was defined as using a combination of medical treatments (anti-TNFs ± immunomodulators ± antibiotics) along with surgical approach (examination under anaesthesia (EUA) ± seton drainage) at diagnosis of CD-pAF. Univariable and multivariable analyses were performed for variables indicative of the need for reintervention.

RESULTS

A total of 253 patients were included. 65% of patients received multimodality approach. Multimodality treatment resulted in complete fistula healing in 52% of patients. Re-intervention was needed in 27% of patients with simple and in 40.3% of those with complex fistula. On multivariable analysis multimodality treatment (OR: 0.35, 95% CI: 0.17-0.57, P = 0.001), seton removal (OR: 0.090, 95% CI: 0.027-0.30, P = 0.0001, therapy with infliximab (OR: 0.19, 95% CI: 0.06-0.64, P = 0.007), and therapy with adalimumab (OR: 0.12, "95% CI: 0.026-0.56, P = 0.007) were predictive of avoiding repeat surgery. Proctitis (OR: 3.76, 95% CI: 1.09-12.96, P = 0.03) was predictive of the need for radical surgery (proctectomy, diverting stoma) while multimodality treatment reduced the need for radical surgery (OR: 0.21, 95% CI: 0.05-0.81, P = 0.02).

CONCLUSIONS

Multimodality treatment, anti-TNFs use, and removal of setons after multimodality treatment can result in improved outcomes in CD patients with perianal fistulae and reduce the need for repeat surgery and radical surgery.

Effectiveness and Safety of Vedolizumab in Anti-TNF-Naïve Patients With Inflammatory Bowel Disease-A Multicenter Retrospective European Study

BACKGROUND

Vedolizumab (VDZ) is effective for treatment of ulcerative colitis (UC) and Crohn's disease (CD). In GEMINI trials, anti-tumor necrosis factor (anti-TNF)-naïve patients had a superior response compared with anti-TNF-exposed patients. In real-world experience (RWE), the number of included anti-TNF-naïve patients was low. We aimed to evaluate the effectiveness and safety of VDZ in anti-TNF-naïve patients in an RWE setting.

METHODS

This retrospective multicenter European pooled cohort study included consecutive active anti-TNF-naïve IBD patients treated with VDZ. The primary end point was clinical response at week 14. Patients with follow-up beyond week 14 and those discontinuing VDZ at any time were included for maintenance outcomes analysis.

RESULTS

Since January 2015, 184 anti-TNF-naïve patients from 23 centers initiated VDZ treatment (Crohn's disease [CD], 50; ulcerative colitis [UC], 134). In CD, 42/50 (82%) patients responded by week 14 and 32 (64%) were in clinical remission; 26/50 (52%) achieved corticosteroid-free remission (CSFR). At last follow-up (44 weeks; interquartile range [IQR], 30-52 weeks), 27/35 (77.1%) patients with available data responded to treatment; 24/35 (68.6%) were in clinical remission, 21/35 (60%) were in CSFR. For UC, 116/134 (79.1%) responded to treatment by week 14, including 53 (39.5%) in clinical remission; 49/134 (36.6%) achieved CSFR. At last follow-up (42.5 weeks; IQR, 30-52 weeks), 79/103 (76.7%) patients responded to treatment, 69/103 (67.0%) were in remission, and 61/103 (59.2%) were in CSFR. Adverse effects were reported in 20 (11%) of the patients, leading to treatment discontinuation in 6 (3.3%).

CONCLUSIONS

VDZ is similarly effective in ant-TNF-naïve CD and UC patients. The efficacy is higher than reported in anti-TNF-experienced patients and is comparable to that of anti-TNF biologics in this population.

Review article: pathogenesis of Crohn's perianal fistula-understanding factors impacting on success and failure of treatment strategies

BACKGROUND

Evidence from groups who have studied fistula aetiology and extrapolation from interventional studies supports a multifactorial hypothesis of Crohn's perianal fistula, with several pathophysiological elements that may contribute to fistula formation, persistence and resistance to treatment.

AIM

An evidence synthesis of current understanding of pathophysiological factors underlying Crohn's perianal fistula is presented, exploring the fundamental reasons why some treatments succeed and others fail, as a means of focussing clinical knowledge on improving treatment of Crohn's perianal fistula.

METHODS

Evidence to support this review was gathered via the Pubmed database. Studies discussing pathophysiological factors underpinning perianal fistula, particularly in Crohn's disease, were reviewed and cross-referenced for additional reports.

RESULTS

Pathophysiological factors that impact on success or failure of interventions for Crohn's perianal fistulae include the high-pressure zone, obliterating the dead space, disconnecting the track from the anus, removing epithelialisation, eradicating sepsis and by-products of bacterial colonisation, correcting abnormalities in wound repair and removing the pro-inflammatory environment which allows fistula persistence. Most current interventions for Crohn's perianal fistulae tend to focus on a single, or at best two, aspects of the pathophysiology of Crohn's anal fistulae; as a result, failure to heal fully is common.

CONCLUSIONS

For an intervention or combination of interventions to succeed, multiple factors must be addressed. We hypothesise that correct, timely and complete attention to all of these factors in a multimodal approach represents a new direction that may enable the creation of an effective treatment algorithm for Crohn's anal fistula.

Golimumab induction and maintenance for moderate to severe ulcerative colitis: results from GO-COLITIS (Golimumab: a Phase 4, UK, open label, single arm study on its utilization and impact in ulcerative Colitis)

Objective

GO-COLITIS aimed to measure the effectiveness of subcutaneous golimumab in tumour necrosis factor-α antagonist–naive patients with moderate to severe ulcerative colitis (UC) despite conventional treatment.

Design

GO-COLITIS was an open label, single arm, phase 4 study with a pragmatic design which reflected UK clinical practice. Adult patients were eligible if diagnosed with UC ≥3 months, partial Mayo score (PMS) 4–9. Patients received subcutaneous golimumab induction (200 mg initially and 100 mg at week 2) followed at week 6 by 50 mg or 100 mg (depending on weight) every 4 weeks until week 54 with a 12-week follow-up. Efficacy was measured by PMS at baseline, week 6, 30, 54 and 66. Health-related quality of life (HRQoL; Inflammatory Bowel Disease Questionnaire (IBDQ) and EuroQol Group 5 Dimensions Health Questionnaire (EQ-5D)) was assessed at baseline, week 6 and week 54. All safety adverse events (AEs) were recorded.

Results

207 patients were enrolled and 205 received golimumab (full analysis set (FAS)205). At week 6, 68.8% (95% CI 62.0% to 75.1%) and 38.5% (95% CI 31.8% to 45.6%) of patients were in response and remission, respectively, using PMS. At the end of the induction phase, 140/141 patients in clinical response continued into the maintenance phase (Maintenance FAS). Sustained clinical response through week 54 was achieved in 51/205 (24.9%) of the FAS205 population and 51/140 (36.4%) of the Maintenance FAS population. Statistically significant improvements from baseline to week 6 were observed for the IBDQ total score and for each IBDQ domain score (bowel symptoms, emotional function, systemic symptoms and social function), as well as the EQ-5D index score and associated visual analogue scale score (p<0.0001). Improvement of HRQoL was sustained through week 54. Serious AEs leading to treatment discontinuation occurred in 8.8% of patients.

Conclusion

In this study measuring patient-reported outcomes in patients with moderate to severe UC, golimumab induced and maintained response as measured by PMS and significantly improved quality of life measures.

Trial registration number

NCT02092285; 2013-004583-56.

Quality of Care in Ulcerative Colitis: A Modified Delphi Panel Approach

OBJECTIVES

To establish clinical consensus on important and relevant quality-of-care (QoC) attributes in ulcerative colitis (UC) treatment that may improve treatment outcomes and guide best practices.

METHODS

Thirty-eight QoC attributes were identified in a literature review. Sixteen European-based experts were selected based on their contributions to UC guidelines, publications, and patient care. A 3-round, modified Delphi panel was conducted including an interview round, and 2 web-based rounds to reach consensus and finalize a QoC attribute list.

RESULTS

The draft QoC attribute list derived from a literature review and Round 1, expert interviews, comprised 63 attributes. In Rounds 2 and 3, the QoC attributes frequently rated as critically important were diagnosis (n = 15, 93.8%), treatment adherence (n = 15, 93.8%), and access to care/treatment (Round 2: n = 14, 87.5%; Round 3: n = 15, 93.8%). The final QoC attribute list consisted of 61 attributes across 20 domains, with the most attributes reported in the "treatment goals" domain (n = 9).

CONCLUSION

QoC is a complex and evolving concept that can improve outcomes while maximizing healthcare resources. Limited time and resources hamper clinicians' ability to openly and empathetically communicate with patients; novel technology may help to offer solutions.

Infliximab versus ciclosporin for steroid-resistant acute severe ulcerative colitis (CONSTRUCT): a mixed methods, open-label, pragmatic randomised trial

Background

Infliximab and ciclosporin are of similar efficacy in treating acute severe ulcerative colitis, but there has been no comparative evaluation of their relative clinical effectiveness and cost-effectiveness.

Methods

In this mixed methods, open-label, pragmatic randomised trial, we recruited consenting patients aged 18 years or older at 52 district general and teaching hospitals in England, Scotland, and Wales who had been admitted, unscheduled, with severe ulcerative colitis and failed to respond to intravenous hydrocortisone within about 5 days. Patients were randomly allocated (1:1) to receive either infliximab (5 mg/kg intravenous infusion given over 2 h at baseline, and again at 2 weeks and 6 weeks after the first infusion) or ciclosporin (2 mg/kg per day by continuous infusion for up to 7 days, followed by twice-daily tablets delivering 5·5 mg/kg per day for 12 weeks). Randomisation used a web-based password-protected site, with a dynamic algorithm to generate allocations on request, thus protecting against investigator preference or other subversion, while ensuring that each trial group was balanced by centre, which was the only stratification used. Local investigators and participants were aware of the treatment allocated, but the chief investigator and analysts were masked. Analysis was by treatment allocated. The primary outcome was quality-adjusted survival—ie, the area under the curve (AUC) of scores from the Crohn's and Ulcerative Colitis Questionnaire (CUCQ) completed by participants at baseline, 3 months, and 6 months, then every 6 months from 1 year to 3 years. This trial is registered with the ISRCTN Registry, number ISRCTN22663589.

Findings

Between June 17, 2010, and Feb 26, 2013, 270 patients were recruited. 135 patients were allocated to the infliximab group and 135 to the ciclosporin group. 121 (90%) patients in each group were included in the analysis of the primary outcome. There was no significant difference between groups in quality-adjusted survival (mean AUC 564·0 [SD 241·9] in the infliximab group vs 587·0 [226·2] in the ciclosporin group; mean adjusted difference 7·9 [95% CI −22·0 to 37·8]; p=0·603). Likewise, there were no significant differences between groups in the secondary outcomes of CUCQ scores, EQ-5D, or SF-6D scores; frequency of colectomy (55 [41%] of 135 patients in the infliximab group vs 65 [48%] of 135 patients in the ciclosporin group; p=0·223); or mean time to colectomy (811 [95% CI 707–912] days in the infliximab group vs 744 [638–850] days in the ciclosporin group; p=0·251). There were no differences in serious adverse reactions (16 reactions in 14 participants receiving infliximab vs ten in nine patients receiving ciclosporin); serious adverse events (21 in 16 patients vs 25 in 17 patients); or deaths (three in the infliximab group vs none in the ciclosporin group).

Interpretation

There was no significant difference between ciclosporin and infliximab in clinical effectiveness.

Funding

NIHR Health Technology Assessment programme.

European Crohn's and Colitis Organisation Topical Review on Treatment Withdrawal ['Exit Strategies'] in Inflammatory Bowel Disease

Clinically effective therapies now exist for remission maintenance in both ulcerative colitis [UC] and Crohn's Disease [CD]. For each major class of IBD medications [5-aminosalicyclates, immunomodulators, and biologic agents], used alone or in combination, there is a risk of relapse following reduction or cessation of treatment. A consensus expert panel convened by the European Crohn's and Colitis Organisation [ECCO] reviewed the published literature and agreed a series of consensus practice points. The objective of the expert consensus is to provide evidence-based guidance for clinical practice so that physicians can make informed decisions in partnership with their patients. The likelihood of relapse with stopping each class of IBD medication is reviewed. Factors associated with an altered risk of relapse with withdrawal are evaluated, and strategies to monitor and allow early identification of relapse are considered. In general, patients in clinical, biochemical, and endoscopic remission are more likely to remain well when treatments are stopped. Reintroduction of the same treatment is usually, but not always, successful. The decision to stop a treatment needs to be individualized, and shared decision making with the patient should take place.

Outcome of elective withdrawal of anti-tumour necrosis factor-α therapy in patients with Crohn's disease in established remission

BACKGROUND AND AIMS

Outcomes of cessation of anti-TNF therapy for Crohn's disease (CD) in clinical and/or endoscopic remission in routine clinical practice is uncertain. This study aimed to evaluate clinical outcomes and factors associated with relapse in CD patients following formal disease assessment and elective anti-TNF withdrawal.

METHODS

Prospective observational study of CD patients in whom anti-TNF therapy was stopped electively after ≥12months and follow-up of ≥6months. Investigations at assessment prior to cessation included ≥1 of clinical assessment, endoscopic and/or imaging. Relapse was defined as recurrent symptoms of CD requiring medical or surgical therapy.

RESULTS

Eighty-six patients received anti-TNF for a median duration of 23 (12-80) months for severe active luminal (70%), fistulating perianal (25.5%) and other fistulating disease (4.5%). Relapse rates at 90,180 and 365days were 4.7%, 18.6% and 36%, respectively. If anti-TNF dose escalation occurred 6months prior to withdrawal, 88% (7/8) relapsed. Based on multivariate analysis, risk factors for relapse include ileocolonic disease at diagnosis and previous anti-TNF therapy. An elevated faecal calprotectin (FC) is likely to predict relapse (p=0.02), with a PPV of 66.7% at >50μg/g. Of 36 patients who relapsed, 31 were retreated with anti-TNF, with an overall recapture rate of 93%.

CONCLUSION

Relapse rates at 1year following elective withdrawal of anti-TNF are 36%, with high retreatment response rate. Predictors of relapse include ileocolonic involvement, previous anti-TNF therapy and raised FC. Endoscopic/radiologic assessment prior to cessation of therapy does not appear to predict those at lower risk of relapse.

Occurrence of Anaemia in the First Year of Inflammatory Bowel Disease in a European Population-based Inception Cohort-An ECCO-EpiCom Study

BACKGROUND AND AIMS

Anaemia is an important complication of inflammatory bowel disease [IBD]. The aim of this study was to determine the prevalence of anaemia and the practice of anaemia screening during the first year following diagnosis, in a European prospective population-based inception cohort.

METHODS

Newly diagnosed IBD patients were included and followed prospectively for 1 year in 29 European and one Australian centre. Clinical data including demographics, medical therapy, surgery and blood samples were collected. Anaemia was defined according to the World Health Organization criteria.

RESULTS

A total of 1871 patients (Crohn's disease [CD]: 686, 88%; ulcerative colitis [UC]: 1,021, 87%; IBD unclassified [IBDU] 164. 81%) were included in the study. The prevalence of anaemia was higher in CD than in UC patients and, overall, 49% of CD and 39% of UC patients experienced at least one instance of anaemia during the first 12 months after diagnosis. UC patients with more extensive disease and those from Eastern European countries, and CD patients with penetrating disease or colonic disease location, had higher risks of anaemia. CD and UC patients in need of none or only mild anti-inflammatory treatment had a lower risk of anaemia. In a significant proportion of patients, anaemia was not assessed until several months after diagnosis, and in almost half of all cases of anaemia a thorough work-up was not performed.

CONCLUSIONS

Overall, 42% of patients had at least one instance of anaemia during the first year following diagnosis. Most patients were assessed for anaemia regularly; however, a full anaemia work-up was frequently neglected in this community setting.

UK guideline on transition of adolescent and young persons with chronic digestive diseases from paediatric to adult care

The risks of poor transition include delayed and inappropriate transfer that can result in disengagement with healthcare. Structured transition care can improve control of chronic digestive diseases and long-term health-related outcomes. These are the first nationally developed guidelines on the transition of adolescent and young persons (AYP) with chronic digestive diseases from paediatric to adult care. They were commissioned by the Clinical Services and Standards Committee of the British Society of Gastroenterology under the auspices of the Adolescent and Young Persons (A&YP) Section. Electronic searches for English-language articles were performed with keywords relating to digestive system diseases and transition to adult care in the Medline (via Ovid), PsycInfo (via Ovid), Web of Science and CINAHL databases for studies published from 1980 to September 2014. The quality of evidence and grading of recommendations was appraised using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. The limited number of studies in gastroenterology and hepatology required the addition of relevant studies from other chronic diseases to be included.These guidelines deal specifically with the transition of AYP living with a diagnosis of chronic digestive disease and/or liver disease from paediatric to adult healthcare under the following headings;1. Patient populations involved in AYP transition2. Risks of failing transition or poor transition3. Models of AYP transition4. Patient and carer/parent perspective in AYP transition5. Surgical perspective.

European Crohn's and Colitis Organisation Topical Review on IBD in the Elderly

This ECCO topical review of the European Crohn's and Colitis Organisation [ECCO] focuses on the epidemiology, pathophysiology, diagnosis, management and outcome of the two most common forms of inflammatory bowel disease, Crohn's disease and ulcerative colitis, in elderly patients. The objective was to reach expert consensus to provide evidence-based guidance for clinical practice.

3rd European Evidence-based Consensus on the Diagnosis and Management of Crohn's Disease 2016: Part 2: Surgical Management and Special Situations

This paper is the second in a series of two publications relating to the European Crohn's and Colitis Organisation [ECCO] evidence-based consensus on the diagnosis and management of Crohn's disease [CD] and concerns the surgical management of CD as well as special situations including management of perianal CD and extraintestinal manifestations. Diagnostic approaches and medical management of CD of this ECCO Consensus are covered in the first paper [Gomollon et al JCC 2016].

Mercaptopurine versus placebo to prevent recurrence of Crohn's disease after surgical resection (TOPPIC): a multicentre, double-blind, randomised controlled trial

BACKGROUND

Up to 60% of patients with Crohn's disease need intestinal resection within the first 10 years of diagnosis, and postoperative recurrence is common. We investigated whether mercaptopurine can prevent or delay postoperative clinical recurrence of Crohn's disease.

METHODS

We did a randomised, placebo-controlled, double-blind trial at 29 UK secondary and tertiary hospitals of patients (aged >16 years in Scotland or >18 years in England and Wales) who had a confirmed diagnosis of Crohn's disease and had undergone intestinal resection. Patients were randomly assigned (1:1) by a computer-generated web-based randomisation system to oral daily mercaptopurine at a dose of 1 mg/kg bodyweight rounded to the nearest 25 mg or placebo; patients with low thiopurine methyltransferase activity received half the normal dose. Patients and their carers and physicians were masked to the treatment allocation. Patients were followed up for 3 years. The primary endpoint was clinical recurrence of Crohn's disease (Crohn's Disease Activity Index >150 plus 100-point increase in score) and the need for anti-inflammatory rescue treatment or primary surgical intervention. Primary and safety analyses were by intention to treat. Subgroup analyses by smoking status, previous thiopurines, previous infliximab or methotrexate, previous surgery, duration of disease, or age at diagnosis were also done. This trial is registered with the International Standard Randomised Controlled Trial Register (ISRCTN89489788) and the European Clinical Trials Database (EudraCT number 2006-005800-15).

FINDINGS

Between June 6, 2008, and April 23, 2012, 240 patients with Crohn's disease were randomly assigned: 128 to mercaptopurine and 112 to placebo. All patients received at least one dose of study drug, and no randomly assigned patients were excluded from the analysis. 16 (13%) of patients in the mercaptopurine group versus 26 (23%) patients in the placebo group had a clinical recurrence of Crohn's disease and needed anti-inflammatory rescue treatment or primary surgical intervention (adjusted hazard ratio [HR] 0·54, 95% CI 0·27-1·06; p=0·07; unadjusted HR 0·53, 95% CI 0·28-0·99; p=0·046). In a subgroup analysis, three (10%) of 29 smokers in the mercaptopurine group and 12 (46%) of 26 in the placebo group had a clinical recurrence that needed treatment (HR 0·13, 95% CI 0·04-0·46), compared with 13 (13%) of 99 non-smokers in the mercaptopurine group and 14 (16%) of 86 in the placebo group (0·90, 0·42-1·94; pinteraction=0·018). The effect of mercaptopurine did not significantly differ from placebo for any of the other planned subgroup analyses (previous thiopurines, previous infliximab or methotrexate, previous surgery, duration of disease, or age at diagnosis). The incidence and types of adverse events were similar in the mercaptopurine and placebo groups. One patient on placebo died of ischaemic heart disease. Adverse events caused discontinuation of treatment in 39 (30%) of 128 patients in the mercaptopurine group versus 41 (37%) of 112 in the placebo group.

INTERPRETATION

Mercaptopurine is effective in preventing postoperative clinical recurrence of Crohn's disease, but only in patients who are smokers. Thus, in smokers, thiopurine treatment seems to be justified in the postoperative period, although smoking cessation should be strongly encouraged given that smoking increases the risk of recurrence.

FUNDING

Medical Research Council.