Subcutaneous golimumab maintains clinical response in patients with moderate-to-severe ulcerative colitis.

BACKGROUND & AIMS: Subcutaneous golimumab, a fully human monoclonal antibody to tumor necrosis factor-α (TNFα), was evaluated as maintenance therapy in TNFα antagonist-naive adults with moderate-to-severe active ulcerative colitis, despite conventional therapy, who responded to golimumab induction therapy. METHODS: We performed a phase 3, double-blind trial of patients who completed golimumab induction trials (Program of Ulcerative Colitis Research Studies Utilizing an Investigational Treatment, eg, PURSUIT). Patients who responded to induction therapy with golimumab (n = 464) were assigned randomly to groups given placebo or injections of 50 or 100 mg golimumab every 4 weeks through week 52. Patients who responded to placebo in the induction study continued to receive placebo. Nonresponders in the induction study received 100 mg golimumab. The primary end point was clinical response maintained through week 54; secondary end points included clinical remission and mucosal healing at both weeks 30 and 54. RESULTS: Clinical response was maintained through week 54 in 47.0% of patients receiving 50 mg golimumab, 49.7% of patients receiving 100 mg golimumab, and 31.2% of patients receiving placebo (P = .010 and P < .001, respectively). At weeks 30 and 54, a higher percentage of patients who received 100 mg golimumab were in clinical remission and had mucosal healing (27.8% and 42.4%) than patients given placebo (15.6% and 26.6%; P = .004 and P = .002, respectively) or 50 mg golimumab (23.2% and 41.7%, respectively). Percentages of serious adverse events were 7.7%, 8.4%, and 14.3% among patients given placebo, 50 mg, or 100 mg golimumab, respectively; percentages of serious infections were 1.9%, 3.2%, and 3.2%, respectively. Among all patients given golimumab in the study, 3 died (from sepsis, tuberculosis, and cardiac failure, all in patients who received 100 mg golimumab) and 4 developed active tuberculosis. CONCLUSIONS: Golimumab (50 mg or 100 mg) maintained clinical response through week 54 in patients who responded to induction therapy with golimumab and had moderate-to-severe active ulcerative colitis; patients who received 100 mg golimumab had clinical remission and mucosal healing at weeks 30 and 54. Safety was consistent with that reported for other TNFα antagonists and golimumab in other approved indications. ClinicalTrials.gov number: NCT00488631.

Subcutaneous golimumab induces clinical response and remission in patients with moderate-to-severe ulcerative colitis.

BACKGROUND & AIMS: Little is known about the efficacy of golimumab, a fully human monoclonal antibody to tumor necrosis factor (TNF) -α, for treatment of ulcerative colitis (UC). We evaluated subcutaneous golimumab induction therapy in TNF-α antagonist-naïve patients with moderate-to-severe UC despite conventional treatment. METHODS: We integrated double-blind phase 2 dose-finding and phase 3 dose-confirmation trials in a study of 1064 adults with UC (Mayo score: 6-12; endoscopic subscore ≥ 2; 774 patients in phase 3). Patients were randomly assigned to groups given golimumab doses of 100 mg and then 50 mg (phase 2 only), 200 mg and then 100 mg, or 400 mg and then 200 mg, 2 weeks apart. The phase 3 primary end point was week-6 clinical response. Secondary end points included week-6 clinical remission, mucosal healing, and Inflammatory Bowel Disease Questionnaire (IBDQ) score change. RESULTS: In phase 2, median changes from baseline in the Mayo score were -1.0, -3.0, -2.0, and -3.0, in the groups given placebo, 100 mg/50 mg, 200/100 mg, and 400/200 mg golimumab, respectively. In phase 3, rates of clinical response at week 6 were 51.0% and 54.9% among patients given 200 mg/100 mg and 400 mg/200 mg golimumab, respectively, vs 30.3% among those given placebo (both, P ≤ .0001). Rates of clinical remission and mucosal healing and mean changes in IBDQ scores were significantly greater in both golimumab groups vs the placebo group (P ≤ .0014, all comparisons). Rates of serious adverse events were 6.1% and 3.0%, and rates of serious infection were 1.8% and 0.5%, in the placebo and golimumab groups, respectively. One patient in the 400 mg/200 mg group died as a result of surgical complications of an ischiorectal abscess. CONCLUSIONS: Treatment with subcutaneous golimumab induces clinical response, remission, and mucosal healing, and increases quality of life in larger percentages of patients with active UC than placebo. ClinicalTrials.gov Number: NCT00487539.

Infliximab or cyclosporine as rescue therapy in hospitalized patients with steroid-refractory ulcerative colitis: a retrospective observational study.

BACKGROUND: Cyclosporine (CsA) or infliximab (IFX) are used as rescue therapies in steroid-refractory, severe attacks of ulcerative colitis (UC). There are no data comparing the efficacy of these two alternatives. METHODS: Outcome of rescue therapy was retrospectively studied in two cohorts of patients hospitalized due to steroid-refractory moderate to severe UC: 1) a Swedish-Danish cohort (n = 49) treated with a single infusion of IFX; 2) an Austrian cohort (n = 43) treated with intravenous CsA. After successful rescue therapy, maintenance immunomodulator treatment was given to 27/33 (82%) of IFX patients and to 31/40 (78%) of CsA patients. Endpoints were colectomy-free survival at 3 and 12 months. Kaplan-Meier and Cox regression models were used to evaluate the association between treatment groups and colectomy. RESULTS: At 15 days, colectomy-free survival in the IFX cohort was 36/49 (73%) versus 41/43 (95%) in the CsA cohort (P = 0.005), at 3 months 33/49 (67%) versus 40/43 (93%) (P = 0.002), and at 12 months 28/49 (57%) versus 33/43 (77%) (P = 0.034). After adjusting for potential confounding factors, Cox regression analysis yielded adjusted hazard ratios for risk of colectomy in IFX-treated patients of 11.2 (95% confidence interval [CI] 2.4-53.1, P = 0.002) at 3 months and of 3.0 (95% CI 1.1-8.2, P = 0.030) at 12 months in comparison with CsA-treated patients. There were no opportunistic infections or mortality. CONCLUSIONS: Colectomy frequencies were significantly lower after rescue therapy with CsA than with a single infusion of IFX both at 3 and 12 months' follow-up. The superiority of CsA was seen principally during the first 15 days.

A pyrosequencing study in twins shows that gastrointestinal microbial profiles vary with inflammatory bowel disease phenotypes.

BACKGROUND & AIMS: The composition of the gastrointestinal microbiota is thought to have an important role in the etiology of inflammatory bowel diseases (IBDs) such as Crohn's disease (CD) and ulcerative colitis (UC). Interindividual variation and an inability to detect less abundant bacteria have made it difficult to correlate specific bacteria with disease. METHODS: We used 454 pyrotag sequencing to determine the compositions of microbial communities in feces samples collected from a cohort of 40 twin pairs who were concordant or discordant for CD or UC, and in mucosal samples from a subset of the cohort. The cohort primarily comprised patients who were in remission, but also some with active disease. RESULTS: The profiles of the microbial community differed with disease phenotypes; relative amounts of bacterial populations correlated with IBD phenotypes. The microbial compositions of individuals with CD differed from those of healthy individuals, but were similar between healthy individuals and individuals with UC. Profiles from individuals with CD that predominantly involved the ileum differed from those with CD that predominantly involved the colon; several bacterial populations increased or decreased with disease type. Changes specific to patients with ileal CD included the disappearance of core bacteria, such as Faecalibacterium and Roseburia, and increased amounts of Enterobacteriaceae and Ruminococcus gnavus. CONCLUSIONS: Bacterial populations differ in abundance among individuals with different phenotypes of CD. Specific species of bacteria are associated with ileal CD; further studies should investigate their role in pathogenesis.

Twin studies reveal specific imbalances in the mucosa-associated microbiota of patients with ileal Crohn's disease.

BACKGROUND: Large interindividual variation in the composition of the intestinal microbiota between unrelated individuals has made it challenging to identify specific aspects of dysbiosis that lead to Crohn's disease (CD). METHODS: To reduce variations in exposure during establishment of the gut flora and the influence of genotype, we studied the mucosa-associated microbiota of monozygotic twin pairs that were discordant (n = 6) or concordant (n = 4) for CD. DNA was extracted from biopsies collected from 5 locations between the ileum and rectum. Bacterial 16S ribosomal RNA genes were amplified and community composition assessed by terminal-restriction fragment length polymorphism, cloning and sequencing, and quantitative real-time polymerase chain reaction (PCR). RESULTS: The microbial compositions at all biopsy locations for each individual were similar, regardless of disease state, but there were differences between individuals. In particular, individuals with predominantly ileal CD had a dramatically lower abundance (P < 0.001) of Faecalibacterium prausnitzii and increased abundance (P < 0.03) of Escherichia coli compared to healthy co-twins and those with CD localized in the colon. This dysbiosis was significantly correlated to the disease phenotype rather than genotype. CONCLUSIONS: The reduced abundance of F. prausnitzii and increased abundance of E. coli are indicative of an ileal CD phenotype, distinct from colonic CD, and the relative abundances of these specific bacterial populations are promising biomarker candidates for differential diagnosis of CD and eventually customized treatment.

Molecular analysis of the gut microbiota of identical twins with Crohn's disease.

Increasing evidence suggests that a combination of host genetics and the composition of the gut microbiota are important for development of Crohn's disease (CD). Our aim was to study identical twins with CD to determine microbial factors independent of host genetics. Fecal samples were studied from 10 monozygotic twin pairs with CD (discordant n=6 and concordant n=4) and 8 healthy twin pairs. DNA was extracted, 16S rRNA genes were PCR amplified and T-RFLP fingerprints generated using general bacterial and Bacteroides group-specific primers. The microbial communities were also profiled based on their percentage G+C contents. Bacteroides 16S rRNA genes were cloned and sequenced from a subset of the samples. The bacterial diversity in each sample and similarity indices between samples were estimated based on the T-RFLP data using a combination of statistical approaches. Healthy individuals had a significantly higher bacterial diversity compared to individuals with CD. The fecal microbial communities were more similar between healthy twins than between twins with CD, especially when these were discordant for the disease. The microbial community profiles of individuals with ileal CD were significantly different from healthy individuals and those with colonic CD. Also, CD individuals had a lower relative abundance of B. uniformis and higher relative abundances of B. ovatus and B. vulgatus. Our results suggest that genetics and/or environmental exposure during childhood, in part, determine the gut microbial composition. However, CD is associated with dramatic changes in the gut microbiota and this was particularly evident for individuals with ileal CD.

Short health scale: a valid, reliable, and responsive instrument for subjective health assessment in Crohn's disease.

BACKGROUND: Health-related quality of life (HRQoL) is an essential part of inflammatory bowel disease (IBD) assessment. The Short Health Scale (SHS), an HRQoL questionnaire in which the patients rate the disease impact on 4 important aspects of subjective health (symptoms, function, worry, and general well-being) was demonstrated in a previous study to be valid, reliable, and responsive in patients with ulcerative colitis. The present study evaluates the SHS in patients with Crohn's disease (CD). METHODS: In all, 367 CD patients completed the SHS and 4 other HRQoL questionnaires (IBDQ, SF-36, RFIPC, and PGWB) at their regular outpatient visits. Then 330 patients completed the questionnaires at a second visit 6 months later. In addition, reliability data were obtained from repeat measurements 4 weeks after the first visit in 40 patients stable in remission. RESULTS: Patients in remission scored better on all 4 questions than those with active disease (P < 0.001). All 4 questions were strongly correlated with the corresponding dimensions of the other HRQoL questionnaires (r(s) = 0.74-0.83). Reliability was confirmed with strong test-retest correlations (r(s) = 0.69-0.82) and intraclass correlation coefficients (0.66-0.77). Patients who changed from remission to active disease or vice versa showed a significant change in all 4 SHS scores (P < 0.005). CONCLUSIONS: SHS is a valid, reliable and responsive HRQoL instrument also in patients with CD. It is easily completed by the patient and requires no further calculation by the investigator. SHS gives a comprehensive overview of the main aspects of the patient's subjective health perception and is a useful tool in both clinical practice and clinical studies.

Longitudinal concordance for clinical characteristics in a Swedish-Danish twin population with inflammatory bowel disease.

BACKGROUND: The genetic influence on disease course in inflammatory bowel disease (IBD) remains unknown. We therefore aimed to study longitudinal concordance for clinical characteristics and longitudinal stability using the Montreal Classification in an IBD twin population. METHODS: A total of 158 twins with ulcerative colitis (UC) (18 belonging to 9 concordant monozygotic pairs) and 141 twins with Crohn's disease (CD) (34 belonging to 17 concordant monozygotic pairs) were enrolled. Medical notes were scrutinized for clinical characteristics at diagnosis and after 10 years. Using the binominal distribution, we tested the hypothesis that clinical characteristics were independent within individuals in disease concordant monozygotic pairs. RESULTS: In CD, location was identical in 11/17 monozygotic concordant pairs at diagnosis (P = 0.008) and in 11/16 pairs after 10 years (P = 0.02). Behavior at diagnosis was identical in 13/17 pairs (P = 0.03) and in 11/16 pairs after 10 years (P = 0.01). Monozygotic UC twins were concordant (within 5 years) for age at diagnosis (6/9 pairs; P < 0.001) and symptomatic onset (4/9 pairs; P = 0.02) but not for extent of disease at diagnosis or after 10 years. The Montreal Classification did not demonstrate longitudinal stability, either regarding location or behavior of CD or extent of UC. CONCLUSIONS: The high phenotypic concordance, both at diagnosis and longitudinally, in monozygotic twins with CD supports a genetic influence not only on disease occurrence but also on disease course. This contrasts with UC, where the genetic impact appears less. Montreal Classification characteristics changed over time and should be used cautiously.

Long-term colectomy rate after intensive intravenous corticosteroid therapy for ulcerative colitis prior to the immunosuppressive treatment era.

OBJECTIVES: Corticosteroids are a cornerstone in the treatment of a severe attack of ulcerative colitis (UC). The long-term prognosis in this patient group is not well described. We studied the long-term colectomy and relapse rates in patients given intensive intravenous corticosteroid treatment (IIVT) for acute UC. METHODS: A retrospective clinical study of 158 patients with UC treated in 1975-1982 with IIVT. Patients were followed-up to death, colectomy or last visit. RESULTS: A total of 11 patients were excluded due to change of diagnosis (N = 10) or lost to follow-up (N = 1). The indication for index IIVT in the remaining 147 patients was a severe attack (N = 61), a moderately severe attack (N = 45), a mild attack (N = 29) or chronic continuous disease (N = 12). The median (range) duration of follow-up was 173 (4-271) months in patients escaping colectomy during the first 3 months. Three months after IIVT, the colectomy rates were 28/61 (46%) in a severe attack, 4/45 (9%) in a moderately severe, and 1/29 (3%) in a mild attack. After 10 yr, the colectomy rates were 39/61 (64%), 22/45 (49%), and 8/29 (28%), respectively. During follow-up, neither colectomy incidence beyond 3 months, time to first relapse nor relapse incidence was influenced by severity of initial attack, except for a lower relapse incidence after a severe attack. CONCLUSIONS: In patients escaping colectomy during the first 3 months after IIVT, the future prognosis was similar irrespective of initial disease severity.

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

BACKGROUND: Genetics and environmental factors are implicated in the etiology of inflammatory bowel disease (IBD). We studied environmental factors in a population-based Swedish-Danish twin cohort using the co-twin control method. SUBJECTS AND METHODS: A questionnaire was sent to 317 twin pairs regarding markers of exposures in the following areas: infections/colonization and diet as well as smoking, appendectomy, and oral contraceptives. Odds ratios (OR) were calculated by conditional logistic regression. When confounding appeared plausible, multivariate conditional logistic regression was added. The questions were also divided into topic groups, and adjustment was made for multiple testing within each of the groups. RESULTS: The response rate to the questionnaire was 83%. In consideration of the study design, only discordant pairs were included (Crohn's disease [CD], n = 102; ulcerative colitis [UC], n = 125). Recurrent gastrointestinal infections were associated with both UC (OR, 8.0; 95% confidence interval [CI], 1.0-64) and CD (OR, 5.5; 95% CI, 1.2-25). Hospitalization for gastrointestinal infections was associated with CD (OR, 12; 95% CI, 1.6-92). Smoking was inversely associated with UC (OR, 0.4; 95% CI, 0.2-0.9) and associated with CD (OR, 2.9; 95% CI, 1.2-7.1). CONCLUSIONS: The observed associations indicate that markers of possible infectious events may influence the risk of IBD. Some of these effects might be mediated by long-term changes in gut flora or alterations in reactivity to the flora. The influence of smoking in IBD was confirmed.

The Short Health Scale: a valid measure of subjective health in ulcerative colitis.

OBJECTIVE: Assessment of health-related quality of life (HRQOL) is important in both clinical practice and clinical trials, and several multi-item questionnaires are currently in use. We have devised and evaluated a simplified four-item questionnaire, the Short Health Scale (SHS), representing each of four health dimensions: (a) symptom burden, (b) social function, (c) disease-related worry and (d) general well-being. MATERIAL AND METHODS: Three hundred patients with ulcerative colitis completed the SHS and three other HRQOL questionnaires (IBDQ, RFIPC and PGWB). Half of the patients repeated the questionnaires after 6 months - or earlier if disease activity changed. Test-retest reliability was derived from measurements of the SHS questions, 2 weeks apart, on 18 patients in remission. RESULTS: Patients in relapse scored higher on each of the four SHS questions than patients in remission (p < 0.001). Each of the four SHS scores were associated with results of their corresponding health dimension obtained with the other three questionnaires (rs=0.57-0.78, p < 0.001) (validity). The results of the SHS proved stable on repeated measurement with a 2-week interval in patients in remission (rs=0.71-0.91, p < 0.01) (test-retest reliability). Patients with a change in disease activity had a significant change in their SHS scores (p < 0.05) (responsiveness). CONCLUSIONS: The SHS is a valid, reliable and responsive measure of subjective health in patients with ulcerative colitis. It is simple to administer, quickly completed and the results do not need further calculations. The SHS can be used in clinical trials and in clinical practice to identify the patient's main problems affecting health.

Evaluation of the Inflammatory Bowel Disease Questionnaire in Swedish patients with Crohn's disease.

OBJECTIVE: Health-related quality of life (HRQoL) is an important measure of inflammatory bowel disease (IBD) health outcome. The Inflammatory Bowel Disease Questionnaire (IBDQ) comprising 32 items grouped into four dimensions is a widely used IBD-specific HRQoL instrument. The purpose of this study was to evaluate the validity, reliability and responsiveness of the Swedish translation of the IBDQ in patients with Crohn's disease (CD). MATERIAL AND METHODS: Four hundred and forty-eight patients with CD completed the IBDQ and three other HRQoL questionnaires (Rating Form of IBD Patient Concerns; Short Form-36; and the Psychological General Well-Being Index) in connection with their regular visit at the outpatient clinic. Disease activity was assessed by the physician on a 4-point Likert scale. Thirty-two patients who were stable in remission completed the questionnaires a second time, 4 weeks later. A total of 418 patients repeated all measurements after 6 months. RESULTS: The dimensional scores were highly correlated with other measures of corresponding aspects of HRQoL and were significantly better in remission than in relapse. High test-retest correlations indicated good reliability. Responsiveness was confirmed in patients whose disease activity changed over time. However, high correlations between the dimensions, poor correlations between items within each dimension, and factor analysis all indicated that the original grouping of the items is not valid for Swedish CD patients. CONCLUSIONS: Although the Swedish IBDQ has good external validity, reliability and responsiveness for patients with CD, our results did not support the original grouping of the items.

[Microscopic colitis--more common cause of diarrhea than believed. Biopsies are the only way to diagnosis, drug treatment is effective]. / Mikroskopisk kolit--vanligare diarrésjukdom än du tror. Biopsier enda väg till diagnos, medicinsk behandling ger god effekt.

Microscopic colitis, encompassing collagenous and lymphocytic colitis, is a fairly common cause of chronic watery diarrhoea, especially in elderly women. In recent epidemiological studies the annual incidence of each disorder was 4-6/100.000 inhabitants. The aetiology is unknown. The main clinical symptoms are watery diarrhoea, weight loss and abdominal pain. Laboratory analyses are nondiagnostic, and the diagnoses rely on histopathological examination of colonic mucosal biopsies. There is an association to autoimmune diseases such as thyroid disorders, diabetes mellitus, celiac disease and arthritis. Budesonide is the best-documented treatment of collagenous colitis. It is superior to placebo in short-term therapy, but the long-term efficacy is not well studied. The evidence for other therapeutic alternatives such as loperamide, cholestyramine, bismuth subsalicylate, or 5-aminosalicylates is weak. In unresponsive severe disease azathioprine or methotrexate may be tried. There are at present no controlled data on the treatment of lymphocytic colitis. The long-term prognosis of microscopic colitis is good, serious complications are rare and there is no increased mortality.

Infliximab as rescue therapy in severe to moderately severe ulcerative colitis: a randomized, placebo-controlled study.

BACKGROUND & AIMS: Despite treatment with corticosteroids, severe to moderately severe attacks of ulcerative colitis have a high colectomy rate. We intended to find a rescue therapy other than cyclosporin A, which imposes a high risk of side effects and cyclosporine-related mortality. METHODS: This was a randomized double-blind trial of infliximab or placebo in severe to moderately severe ulcerative colitis not responding to conventional treatment. Patients were randomized to infliximab/placebo either on day 4 after the initiation of corticosteroid treatment if they fulfilled the index criteria for fulminant ulcerative colitis on day 3 or on day 6-8 if they fulfilled index criteria on day 5-7 for a severe or moderately severe acute attack of ulcerative colitis. Results were analyzed according to the intention-to-treat principle. The primary end point was colectomy or death 3 months after randomization. Secondary end points were clinical and endoscopic remission at that time in patients who did not undergo operation. RESULTS: Forty-five patients were included (24 infliximab and 21 placebo). No patient died. Seven patients in the infliximab group and 14 in the placebo group had a colectomy (P = .017; odds ratio, 4.9; 95% confidence interval, 1.4-17) within 3 months after randomization. No serious side effects occurred. Three patients in the placebo group required operation for septic complications. CONCLUSIONS: Infliximab 4-5 mg/kg is an effective and safe rescue therapy in patients experiencing an acute severe or moderately severe attack of ulcerative colitis not responding to conventional treatment.

Colonic perforation in collagenous colitis: an unusual complication.

Collagenous colitis is generally regarded as a benign disease with few serious complications. We report two women with collagenous colitis who presented with colonic perforation, one spontaneously and one 7 days after a barium enema, and a review of the literature. Including the present cases, 13 patients with collagenous colitis and colonic perforation have been reported, in two patients spontaneously and in 11 patients after a colonoscopy or barium enema. All were operated on except one patient who recovered after medical treatment. The pathogenesis of this complication is unknown. We propose that there might be a connection between mucosal tears and colonic perforation in collagenous colitis.

The influence of demographic and disease-related factors on health-related quality of life in patients with ulcerative colitis.

OBJECTIVE: The aims of this study were to analyse the health-related quality of life of patients with ulcerative colitis and to assess in what way demographic and disease-related factors influence patients' experiences of this, in order to interpret the results of health-related quality of life assessment more correctly. PATIENTS AND METHODS: We carried out a cross-sectional evaluation of 300 consecutive patients with ulcerative colitis from the catchment areas of Linköping University Hospital and Orebro University Hospital in Sweden. Health-related quality of life was measured using four questionnaires: the IBDQ, the RFIPC, the SF-36 and the PGWB. Disease activity was evaluated using a one-week symptom diary, blood tests and rigid sigmoidoscopy. Demographic factors (gender, age, civil status, educational level), disease-related factors (disease duration, disease extent, disease activity) and presence of co-morbidity were obtained. RESULTS: Health-related quality of life was mainly impaired in the psychological and social areas and to a much lesser degree in physical areas. Patients with relapse had significantly more disease-related worries and concerns (the RFIPC), more impaired social functioning (the IBDQ and SF-36), and a lower feeling of well being (the IBDQ, the SF-36 and the PGWB). However, their physical function (SF-36) was no worse than patients in remission. Besides the symptom burden of the current disease, co-morbidity and female gender were associated with a lower health-related quality of life. CONCLUSION: To correctly interpret health-related quality of life assessments, it is necessary to consider co-morbidity and gender distribution in addition to the symptom burden of the disease studied.

Inflammatory bowel disease in a Swedish twin cohort: a long-term follow-up of concordance and clinical characteristics.

BACKGROUND & AIMS: In 1988, we reported the first twin study in inflammatory bowel disease. The aim of the current study was to follow up these twins regarding new cases of inflammatory bowel disease and Crohn's disease characteristics using the Vienna classification. METHODS: The official Swedish population register and the cause of death register were used to search for the twins. All living patients were interviewed. RESULTS: Three monozygotic twins earlier classified as healthy had been diagnosed with inflammatory bowel disease (ulcerative colitis, n = 2; Crohn's disease, n = 1). Retrospectively, all 3 were symptomatic at the original survey. This changed the pair concordance in monozygotic twins from 6.3% to 18.8% in ulcerative colitis and from 44.4% to 50.0% in Crohn's disease. A high degree of concordance regarding age at diagnosis, disease location at diagnosis and during the course, and disease behavior was found in concordant monozygotic twin pairs with Crohn's disease. Seven of 9 pairs were identical in 3 or more of these disease characteristics compared with an expected number of 1.5 (P = 0.000076). CONCLUSIONS: This study confirms that the genetic influence is stronger in Crohn's disease than in ulcerative colitis. A remarkable phenotype similarity within concordant pairs with Crohn's disease was found using the Vienna classification.