[Epidemiology and risk factors of inflammatory bowel diseases]

Inflammatory bowel diseases (IBD) are a public health problem in industrialized countries, where 1 in 1000 people are affected Most patients are young adults. The incidence of IBD has increased considerably in western countries since the second world war but is beginning to level off. On the other hand, the incidence is still rising in low-incidence areas such as Eastern Europe, Asia and developing countries. Differences in incidence rates across age, time, and geographic areas suggest that environmental factors are involved in IBD, but only cigarette smoking and appendectomy have consistently been identified as risk factors. An important role of genetic factors in IBD was first suggested by epidemiological studies showing familial aggregation of IBD and by twin studies. In 2001, the first CD susceptibility gene, NOD2/CARD15 on chromosome 16, was characterized. Other susceptibility genes have since been located. Their identification should help to understand the complex interaction between the environment and the intestinal immune system.

CEACAM6 acts as a receptor for adherent-invasive E. coli, supporting ileal mucosa colonization in Crohn disease

The ileal mucosa of Crohn disease (CD) patients is abnormally colonized by adherent-invasive E. coli (AIEC) that are able to adhere to and invade intestinal epithelial cells. Here, we show that CD-associated AIEC strains adhere to the brush border of primary ileal enterocytes isolated from CD patients but not controls without inflammatory bowel disease. AIEC adhesion is dependent on type 1 pili expression on the bacterial surface and on carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) expression on the apical surface of ileal epithelial cells. We report also that CEACAM6 acts as a receptor for AIEC adhesion and is abnormally expressed by ileal epithelial cells in CD patients. In addition, our in vitro studies show that there is increased CEACAM6 expression in cultured intestinal epithelial cells after IFN-gamma or TNF-alpha stimulation and after infection with AIEC bacteria, indicating that AIEC can promote its own colonization in CD patients.

Aseptic abscesses: a study of 30 patients with or without inflammatory bowel disease and review of the literature

Aseptic abscesses (AA) are characterized by deep, sterile, round lesions consisting of neutrophil that do not respond to antibiotics but improve dramatically with corticosteroids. We report the clinical, laboratory, and radiologic characteristics and the associated conditions of 29 patients from the French Register on AA plus 1 patient from the Netherlands.The mean age of patients at AA diagnosis was 29 years (SD = 14). The main clinical manifestations of AA were fever (90%), abdominal pain (67%), and weight loss (50%). Duration of symptoms was 4.7 months on average until abscesses were discovered. The abscesses involved the spleen in 27/29 patients (93%; the thirtieth patient had a personal history of splenectomy after a trauma). In 7 they were unifocal and in the others they were multifocal, involving in addition the abdominal lymph nodes in 14 (48%), liver in 12 (40%), lung in 5 (17%), pancreas in 2 (7%), and brain in 2 (7%). They were not splenic in 3, including 2 with abdominal lymph nodes and 1 with superficial lymph nodes and testicle and lung involvement. Twenty-two patients (70%) had elevated white blood cell and neutrophil count; antineutrophil cytoplasmic autoantibodies with a perinuclear, cytoplasmic or atypical pattern (negative for antiproteinase 3 and negative for antimyeloperoxidase except for 1) were positive in 21% of the 24 patients tested. Twenty-one patients had inflammatory bowel disease (IBD), which preceded the occurrence of abscesses in 7, was concomitant in 7, and appeared secondarily in 7. Six patients had neutrophilic dermatosis (20%), 3 had relapsing polychondritis as an associated condition, and 3 others had monoclonal gammopathy of undetermined significance. Three patients had no associated condition. Splenectomy was performed in 15 (52%) patients. All patients received steroid therapy. Thirteen (43%) were given additional immunosuppressive therapy, 1 immediately and the others after a relapse, of whom 3 were also treated by anti-tumor necrosis factor-alpha agents. Mean follow-up was 7 years. Eighteen (60%) patients experienced 1 or several relapses, but there was no death related to AA. Relapses occurred on immunosuppressive therapy in 2 patients and off immunosuppressive therapy in the others while corticosteroids were being tapered. We surveyed the literature and analyzed 19 additional cases. AA is an emergent and probably underrecognized entity. It represents an apparently noninfectious inflammatory disorder involving neutrophils that responds to corticosteroid therapy. AA mainly affects patients with IBD but also affects those with other conditions, or with no other apparent disease.

Polymorphism in IgG Fc receptor gene FCGR3A and response to infliximab in Crohn's disease: a subanalysis of the ACCENT I study

Recently, it has been shown that FCGR3A-158 gene polymorphism is associated with biological and possibly clinical response to infliximab in Crohn's disease. We further assessed this association in a subset of 344 patients from the large and well-defined cohort of 573 patients with Crohn's disease from the ACCENT I study. No association could be observed between FCGR3A-158 gene polymorphism and the clinical response to infliximab, which was primarily defined as a decrease of >or=70 points in the Crohn's disease activity index or clinical remission (Crohn's disease activity index <150). We did, however, confirm a trend towards a greater decrease in C-reactive protein after infliximab in V/V homozygotes as compared with V/F heterozygotes and F/F homozygotes (-79.4, -76.5, and -64.3%, respectively, at week 6; P=0.085; one-tailed P=0.043). This finding has no immediate clinical impact but may enhance the understanding of the complex mechanisms of action of anti-tumor necrosis factor agents in Crohn's disease.

Adalimumab for maintenance of clinical response and remission in patients with Crohn's disease: the CHARM trial

BACKGROUND & AIMS

This study evaluated the efficacy and safety of adalimumab, a fully human, anti-tumor necrosis factor monoclonal antibody administered subcutaneously, in the maintenance of response and remission in patients with moderate to severe Crohn's disease (CD).

METHODS

Patients received open-label induction therapy with adalimumab 80 mg (week 0) followed by 40 mg (week 2). At week 4, patients were stratified by response (decrease in Crohn's Disease Activity Index > or =70 points from baseline) and randomized to double-blind treatment with placebo, adalimumab 40 mg every other week (eow), or adalimumab 40 mg weekly through week 56. Co-primary end points were the percentages of randomized responders who achieved clinical remission (Crohn's Disease Activity Index score <150) at weeks 26 and 56.

RESULTS

The percentage of randomized responders in remission was significantly greater in the adalimumab 40-mg eow and 40-mg weekly groups versus placebo at week 26 (40%, 47%, and 17%, respectively; P < .001) and week 56 (36%, 41%, and 12%, respectively; P < .001). No significant differences in efficacy between adalimumab eow and weekly were observed. More patients receiving placebo discontinued treatment because of an adverse event (13.4%) than those receiving adalimumab (6.9% and 4.7% in the 40-mg eow and 40-mg weekly groups, respectively).

CONCLUSIONS

Among patients who responded to adalimumab, both adalimumab eow and weekly were significantly more effective than placebo in maintaining remission in moderate to severe CD through 56 weeks. Adalimumab was well-tolerated, with a safety profile consistent with previous experience with the drug.

Lactobacillus acidophilus modulates intestinal pain and induces opioid and cannabinoid receptors

Abdominal pain is common in the general population and, in patients with irritable bowel syndrome, is attributed to visceral hypersensitivity. We found that oral administration of specific Lactobacillus strains induced the expression of mu-opioid and cannabinoid receptors in intestinal epithelial cells, and mediated analgesic functions in the gut-similar to the effects of morphine. These results suggest that the microbiology of the intestinal tract influences our visceral perception, and suggest new approaches for the treatment of abdominal pain and irritable bowel syndrome.

Quantitative measurement and visual assessment of ileal Crohn's disease activity by computed tomography enterography: correlation with endoscopic severity and C reactive protein

BACKGROUND

Few studies have correlated computed tomography (CT) enterography findings with endoscopic severity and C reactive protein (CRP) concentrations.

AIM

To examine whether small bowel inflammation at CT enterography correlates with endoscopic severity and CRP in patients with Crohn's disease (CD).

METHODS

CT enterography datasets from 143 CD patients undergoing ileoscopy were examined for three different CT parameters: CT bowel enhancement, as defined by the ratio of terminal ileal versus control ileal loop attenuation; vascular enlargement of the vasa recta ("the comb sign"); and mesenteric fat density. Correlations between CT scan parameters, endoscopy, and histology severity scores, and CRP were assessed using Spearman's rank correlation and logistic regression.

RESULTS

Endoscopic score was significantly correlated with CT bowel enhancement, comb sign, and fat density (Spearman correlation coefficients 0.33-0.39; p<0.001). Correlations with histological inflammation were strongest for bowel enhancement (r = 0.34-0.38; p<0.001). CRP was elevated in patients with increased fat density versus those with increased bowel enhancement only (median 0.96 v 0.23, p = 0.002). CRP did not differ significantly between patients without evidence of active Crohn's and those with bowel enhancement and endoscopic inflammation not involving the perienteric tissues by CT (median 0.24 v 0.36; p = 0.38).

CONCLUSION

Quantitative measures of bowel enhancement at CT enterography correlate with endoscopic and histological severity. CRP correlates with radiological findings of perienteric inflammation (increased fat density), but not of inflammation limited to the small bowel wall, underscoring the potential role of perienteric inflammation in CRP response in CD.

No evidence for an involvement of the p38 and JNK mitogen-activated protein in inflammatory bowel diseases

Involvement of mitogen-activated protein (MAPK) in inflammatory bowel disease (IBD) remains enigmatic. We sought to evaluate the expression and activity of p38 and JNK MAPK in IBD and 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis; and the effects of a p38 inhibitor, SB203580, in TNBS colitis. P38 and JNK were quantified in colonic mucosa of 28 IBD patients and 19 controls and in 77 TNBS or control mice treated or not with SB203580. Colitis severity was assessed by survival, macroscopic and microscopic scoring, and molecular markers. Expression and activity of p38 and JNK were similar in IBD patients and controls and not modified by inflammation. In mice, p38 and JNK expression or activity did not increase following the induction of colitis. SB203580 decreased the p38 activity but displayed no clinical nor biological therapeutic effect. In conclusion, these results minimize the role of p38 and JNK in inflammatory colitis and the interest of p38 as a therapeutic target in IBD.

Multilocus sequence typing reveals intrafamilial transmission and microevolutions of Candida albicans isolates from the human digestive tract

Candida albicans is a human commensal that is also responsible for superficial and systemic infections. Little is known about the carriage of C. albicans in the digestive tract and the genome dynamics that occur during commensalisms of this diploid species. The aim of this study was to evaluate the prevalence, diversity, and genetic relationships among C. albicans isolates recovered during natural colonization of the digestive tract of humans, with emphasis on Crohn's disease patients who produce anti-yeast antibodies and may have altered Candida sp. carriage. Candida sp. isolates were recovered from 234 subjects within 25 families with multiple cases of Crohn's disease and 10 control families, sampled at the oral and fecal sites. Prevalences of Candida sp. and C. albicans carriage were 53.4% and 46.5%, respectively, indicating frequent commensal carriage. No differences in prevalence of carriage could be observed between Crohn's disease patients and healthy subjects. Multilocus sequence typing (MLST) of C. albicans isolates revealed frequent colonization of a subject or several members of the same family by genetically indistinguishable or genetically close isolates. These latter isolates differed by loss-of-heterozygosity events at one or several of the MLST loci. These loss-of-heterozygosity events could be due to either chromosome loss followed by duplication or large mitotic recombination events between complementary chromosomes. This study was the first to jointly assess commensal carriage of C. albicans, intrafamilial transmission, and microevolution. The high frequency of each of these events suggests that the digestive tract provides an important and natural niche for microevolutions of diploid C. albicans through the loss of heterozygosity.

Wireless capsule endoscopy versus ileocolonoscopy for the diagnosis of postoperative recurrence of Crohn's disease: a prospective study

BACKGROUND AND AIMS

Following ileocolonic resection for Crohn's disease (CD), early endoscopic recurrence predicts recurrence of symptoms. The aim of the study was to compare ileocolonoscopy and wireless capsule endoscopy (WCE) for the detection of postoperative recurrence in CD.

METHODS

WCE and ileocolonoscopy were performed within six months following surgery in 32 prospectively enrolled patients. Two independent observers interpreted the results of WCE. Recurrence in the neoterminal ileum was defined by a Rutgeerts score>or=1. When observers at WCE did not concur, WCE results were considered as either true negative or true positive and sensitivity and specificity were calculated according to both assumptions.

RESULTS

Recurrence occurred in 21 patients (68%) and was detected by ileocolonoscopy in 19 patients. Sensitivity was 90% and specificity 100%. Sensitivity of WCE was 62% and 76% and specificity was 100% and 90%, respectively, depending on assumptions. There was a correlation between the severity of the lesions measured by both methods (p<0.05). Lesions located outside the scope of conventional endoscopy were detected by WCE in two thirds of patients with excellent interobserver agreement (kappa>0.9) for all lesions with the exception of ulceration (kappa=0.7).

CONCLUSIONS

The sensitivity of WCE in detecting recurrence in the neoterminal ileum was inferior to that of ileocolonoscopy. In contrast, WCE detected lesions outside the scope of ileocolonoscopy in more than two thirds of patients. Additional follow up studies are needed to assess the clinical relevance of such lesions. At the present time, it seems that WCE cannot systematically replace ileocolonoscopy in the regular management of patients after surgery.

A simple biological score for predicting low risk of short-term relapse in Crohn's disease

BACKGROUND

In Crohn's disease, studies have evaluated the ability of biological markers to predict relapse in the next 12 to 18 months, without differentiating early from late relapses. The aim of this study was to look for biological markers of short-term relapse.

MATERIALS AND METHODS

In a previous therapeutic trial, patients with a medically induced clinical remission had biological markers evaluated and updated every 6 weeks. A Cox model with time-dependent covariates was used for analysis.

RESULTS

Among the 71 patients, 38 had a relapse. Multivariate analysis selected 2 markers predictive of relapse: C-reactive protein >20 mg/L and erythrocyte sedimentation rate >15 mm. A binary biological predictive score was derived: "negative" when both were lower than their limits, "positive" when otherwise. The relative risk of short-term relapse for patients with a positive score compared to those with a negative score was 8.0 (95% confidence interval 2.8-22.9). Sensitivity of the score was 89% and specificity was 43%. Assuming a 10% relapse rate every 6 weeks, negative and positive predictive values were 97% and 15%, respectively.

CONCLUSIONS

This simple biological score can predict short-term maintenance of remission in Crohn's disease and may help physicians in the follow-up of patients in clinical remission.

Ineffectiveness of Lactobacillus johnsonii LA1 for prophylaxis of postoperative recurrence in Crohn's disease: a randomised, double blind, placebo controlled GETAID trial

BACKGROUND AND AIMS

Early endoscopic recurrence is frequent after intestinal resection for Crohn's disease. Bacteria are involved, and probiotics may modulate immune responses to the intestinal flora. Here we tested the probiotic strain Lactobacillus johnsonii LA1 in this setting.

PATIENTS AND METHODS

This was a randomised, double blind, placebo controlled study. Patients were eligible if they had undergone surgical resection of <1 m, removing all macroscopic lesions within the past 21 days. Patients were randomised to receive two packets per day of lyophilised LA1 (2 x 10(9) cfu) or placebo for six months; no other treatment was allowed. The primary endpoint was endoscopic recurrence at six months, with grade >1 in Rutgeerts' classification or an adapted classification for colonic lesions. Endoscopic score was the maximal grade of ileal and colonic lesions. Analyses were performed primarily on an intent to treat basis.

RESULTS

Ninety eight patients were enrolled (48 in the LA1 group). At six months, endoscopic recurrence was observed in 30/47 patients (64%) in the placebo group and in 21/43 (49%) in the LA1 group (p = 0.15). Per protocol analysis confirmed this result. Endoscopic score distribution did not differ significantly between the LA1 and placebo groups. There were four clinical recurrences in the LA1 group and three in the placebo group.

CONCLUSION

L johnsonii LA1 (4 x 10(9) cfu/day) did not have a sufficient effect, if any, to prevent endoscopic recurrence of Crohn's disease.

Candida albicans is an immunogen for anti-Saccharomyces cerevisiae antibody markers of Crohn's disease

BACKGROUND AND AIMS

Antibodies directed against oligomannose sequences alpha-1,3 Man (alpha-1,2 Man alpha-1,2 Man)(n) (n = 1 or 2), termed anti-Saccharomyces cerevisiae antibodies (ASCAs) are markers of Crohn's disease (CD). S. cerevisiae mannan, which expresses these haptens, is used to detect ASCA, but the exact immunogen for ASCA is unknown. Structural and genetic studies have shown that Candida albicans produces mannosyltransferase enzymes that can synthesize S cerevisiae oligomannose sequences depending on growth conditions. This study investigated whether C. albicans could act as an immunogen for ASCA.

METHODS

Sequential sera were collected from patients with CD, systemic candidiasis, and rabbits infected with C. albicans. Antibodies were purified by using chemically synthesized (Sigma) ASCA major epitopes. These affinity-purified antibodies and lectins were then used to analyze the expression of ASCA epitopes on molecular extracts and cell walls of C. albicans and S cerevisiae grown in various conditions.

RESULTS

In humans and rabbits, generation of ASCA was shown to be associated with the generation of anti-C. albicans antibodies resulting specifically from infection. By using affinity-purified antibodies, C. albicans was shown to express ASCA epitopes on mannoproteins similar to those of S. cerevisiae. By changing the growth conditions, C. albicans mannan was also able to mimic S. cerevisiae mannan in its ability to detect ASCA associated with CD. This overexpression of ASCA epitopes was achieved when C. albicans grew in human tissues.

CONCLUSIONS

C. albicans is one of several immunogens for ASCA and may be at the origin of an aberrant immune response in CD.

Colectomy with ileorectal anastomosis preserves female fertility in ulcerative colitis

OBJECTIVES

Restorative proctocolectomy with ileoanal anastomosis (IPAA) is the surgical standard for patients with ulcerative colitis (UC). Significant reduction in female fertility and fecundity after IPAA has been shown in recent studies. In selected cases, colectomy with ileorectal anastomosis (IRA) is another surgical option. The aim of this study was to evaluate fertility in women with UC who underwent IRA.

PATIENTS AND METHODS

This study included all women with UC who underwent IRA between 1962 and 1999 and who were 40 years old or younger at the time of surgery, and older than 18 years of age at the time of the interview. Data were collected using a structured telephone interview concerning reproductive behavior and waiting times to pregnancy.

RESULTS

Among 40 eligible patients, 37 whose mean age at IRA was 28 years (range 11-39) answered the questionnaire. Twenty-two were unmarried, not wishful of pregnancy and/or already had children. Among 15 females wishing children after IRA, 10 (66%) became pregnant: one had therapeutic abortion, two had a miscarriage, four had 1 child, two had 2 children and one had 4 children. Five patients were sterile after IRA.

CONCLUSION

These preliminary results suggest that IRA for UC preserves female fertility. If confirmed in other series this information should be provided to young women with UC before deciding surgical option.

Anti-Saccharomyces cerevisiae antibodies in twins with inflammatory bowel disease

BACKGROUND AND AIMS

An increased occurrence of anti-Saccharomyces cerevisiae antibodies (ASCA) is reported in unaffected members of families with Crohn's disease. Whether ASCA is a familial trait due to genetic factors or is caused by exposure to environmental factors is unknown. To assess the genetic influence of ASCA we studied its occurrence in a twin population.

PATIENTS AND METHODS

ASCA were analysed in 98 twin pairs with inflammatory bowel disease and were related to clinical phenotype and CARD15/NOD2 genotype.

RESULTS

ASCA were more common in Crohn's disease than in ulcerative colitis (40/70 (57%) twins v 5/43 (12%) twins). Associations with ileal Crohn's disease, stricturing/penetrating behaviour, and young age, but not CARD15/NOD2 were confirmed. ASCA were found in 1/20 (5%) healthy siblings in discordant monozygotic pairs with Crohn's disease compared with 7/27 (26%) in discordant dizygotic pairs. Using the intraclass correlation coefficient (ICC), no agreement in ASCA titres was observed in discordant twin pairs with Crohn's disease, in monozygotic (ICC = -0.02) or dizygotic (ICC = -0.26) pairs. In contrast, strong agreement was seen within concordant monozygotic twin pairs with Crohn's disease (ICC = 0.76).

CONCLUSIONS

These findings question the concept of ASCA as a marker of genetic susceptibility for Crohn's disease. The agreement in ASCA titres within concordant monozygotic twin pairs with Crohn's disease, suggests that the level of increase is genetically determined. We propose that ASCA are a marker of a response to an environmental antigen and that a specific gene(s) other than CARD15/NOD2 determines the level of response and perhaps also specific phenotypic characteristics.

[Eosinophilic gastroenteritis in a tropical area: report of a Congolese case]

Eosinophilic gastroenteritis is an uncommon disease with an unknown natural history, and its relation to digestive allergies has not been confirmed. This study reports the case of a 27 year old patient who developed eosinophilic gastroenteritis with gastric, intestinal, rectal and peritoneal localisations. In the Congo, massive blood hypereosinophilia suggests digestive parasitosis and gastroenteritis with malnutrition and cutaneous symptoms suggest AIDS/HIV, making the present agnosis uncommon.

Inflammation increases sufentanil requirements during surgery for inflammatory bowel diseases

BACKGROUND AND OBJECTIVE

Inflammation promotes hyperalgesia and increases opioid binding protein (alpha1-acid glycoprotein) inducing increased opioid requirement. To investigate the influence of an acute episode of inflammatory bowel disease in opioid requirement during major abdominal surgery, 17 patients with Crohn's disease, 12 patients with ulcerative colitis and seven patients without any inflammatory process (control group) were prospectively studied. Sufentanil requirements were assessed during surgery.

METHODS

Sufentanil administration was adjusted when haemodynamic variables changed more than 20% of preoperative values. In a subgroup of 20 patients (Crohn's disease: 7, ulcerative colitis: 7, control group: 6), plasma concentrations of alpha1-acid glycoprotein and unbound sufentanil were measured. Total plasma clearance of sufentanil was also determined. Data presented as median (25-75 per thousand) were analysed by non-parametric and ANOVA tests.

RESULTS

Despite similar surgery duration, intraoperative sufentanil requirements were significantly larger in both the Crohn's disease group (0.9 (0.6-1.6) microg kg(-1) h(-1)) and the ulcerative colitis group (1.1 (0.6-1.7) microg kg(-1) h(-1)) than in the control group (0.5 (0.4-0.5) microg kg(-1) h(-1)). Total plasma clearance of sufentanil was larger in patients with inflammatory bowel disease than in the control group. The plasma alpha1-acid glycoprotein concentration was increased in the inflammatory bowel disease group. However, the free fraction of sufentanil was similar in all three groups. The largest sufentanil consumption in patients with inflammatory bowel disease was observed during time of pain stimulation in the area of referred hyperalgesia from the affected viscus. In the control group, the sufentanil requirement was constant throughout surgery.

CONCLUSION

Inflammatory bowel disease increases opioid requirement during major abdominal surgery.

Incidence, clinical presentation and location at diagnosis of pediatric inflammatory bowel disease: a prospective population-based study in northern France (1988-1999)

OBJECTIVE

To assess the incidence and location at diagnosis of inflammatory bowel disease in children and adolescents in northern France between 1988 and 1999.

METHODS

A 12-year prospective population-based study was conducted by gastroenterologists and pediatric gastroenterologists of northern France (1,312,141 children <17 years of age).

RESULTS

From 1988 to 1999, 509 cases of childhood inflammatory bowel disease were recorded (7.2% of all inflammatory bowel disease cases in Northern France): 367 Crohn disease, 122 ulcerative colitis and 20 indeterminate colitis. The mean standardized incidence was 3.1/10(5) for inflammatory bowel disease as a whole (2.3 for Crohn disease, 0.8 for ulcerative colitis and 0.12 for indeterminate colitis). Crohn disease location at diagnosis was: small bowel and colon (71%), colon only (10%) and small bowel only (19%). Location of initial ulcerative colitis was: proctitis (11%), left colitis (57%) and pancolitis (32%). Although ulcerative colitis incidence remained stable (0.8), Crohn disease incidence increased from 2.1 in 1988 to 1990 to 2.6 in 1997 to 1999 (P = 0.2).

CONCLUSIONS

The incidence of Crohn disease in the children of northern France showed an increasing trend (20%; not significant) during the 12-year period while the incidence of ulcerative colitis remained stable. In the entire population(children and adults)the incidence of Crohn disease increased significantly (+23%; P < 0.001), while the incidence of ulcerative colitis decreased (-17%; P < 0.0001).

A randomized, double-blind, controlled withdrawal trial in Crohn's disease patients in long-term remission on azathioprine

BACKGROUND & AIMS

An open study reported that patients with Crohn's disease in remission who have taken azathioprine for longer than 3.5 years are at low risk of relapse when azathioprine is discontinued. To confirm this observation, we performed a multicenter, double-blind, noninferiority withdrawal study.

METHODS

Patients who were in clinical remission on azathioprine for > or = 42 months were randomized to continue azathioprine or to receive an equivalent placebo for 18 months. The primary end point was clinical relapse at 18 months.

RESULTS

Forty patients were randomly assigned to receive azathioprine and 43 to receive placebo. Characteristics of patients at entry were similar in the 2 study groups. At 18 months, 3 patients had a relapse in the azathioprine group, and 9 had a relapse in the placebo group. Kaplan-Meier estimates of the relapse rate at 18 months were 8% +/- 4% and 21% +/- 6%, respectively. The hypothesis that placebo was inferior to azathioprine was not rejected (P = .195). Among the baseline variables, C-reactive protein level > 20 mg/L, time without steroids < 50 months, and hemoglobin level < 12 g/dL were found to be predictive of relapse in the multivariate analysis.

CONCLUSIONS

This study shows that azathioprine withdrawal is not equivalent to continued therapy with azathioprine for maintenance of remission in patients with Crohn's disease who have been in remission on azathioprine for > or = 3.5 years. Thus, azathioprine maintenance therapy should be continued beyond 3.5 years.