BACKGROUND Crohn's disease is a heterogeneous disorder with both a genetic and environmental aetiology. Clinical classifications of the disease, such as the newly proposed Vienna classification, may help to define subgroups of patients suitable for studying the influence of specific genetic or environmental factors. AIM To assess the stability over the course of the disease of its location and behaviour, as determined according to the Vienna classification. PATIENTS AND METHODS The notes of 297 Crohn's disease patients regularly followed up at our institution were carefully reviewed retrospectively. The behaviour and location of the disease according to the Vienna classification were determined at diagnosis and after 1, 3, 5, 10, 15, 20, and 25 years of follow up. The proportions of the different behaviours and locations of the disease were calculated at these time points. A statistical analysis of the evolution of these characteristics over 10 years was performed on a subgroup of 125 patients with at least 10 years of follow up. The influence of age at diagnosis on location and behaviour of the disease was assessed as well as the influence of location on the behaviour of the disease. RESULTS The location of the disease remained relatively stable over the course of the disease. Although the proportion of patients who had a change in disease location became statistically significant after five years (p=0.01), over 10 years only 15.9% of patients had a change in location (p<0.001). We observed a more rapid and prominent change in disease behaviour, which was already statistically significant after one year (p=0.04). Over 10 years, 45.9% of patients had a change in disease behaviour (p<0.0001). The most prominent change was from non-stricturing non-penetrating disease to either stricturing (27.1%; p<0.0001) or penetrating (29.4%; p<0.0001) disease. Age at diagnosis had no influence on either location or behaviour of disease. Ileal Crohn's disease was more often stricturing, and colonic or ileocolonic Crohn's disease was more often penetrating: this was already the case at diagnosis and became more prominent after 10 years (p<0.05). CONCLUSIONS Location of Crohn's disease, as defined by the Vienna classification, is a relatively stable phenotype which seems suitable for phenotype-genotype analyses. Behaviour of Crohn's disease according to the Vienna classification varies dramatically over the course of the disease and cannot be used in phenotype-genotype analyses. The potential influence of genes on the behaviour of Crohn's disease should be studied in subgroups of patients defined by their disease behaviour after a fixed duration of disease.

Objective. A model based on clinical characteristics at diagnosis and predicting the early development of disabling Crohn's disease (CD) has recently been proposed in order to target patients for early intervention. The objectives of this study were to confirm the predictive factors established in a previous study and to establish the predictive factors for the development of severe disease characterized by the development of clinically significant non-reversible damage. Material and methods. Our retrospective study comprised a total of 361 patients with CD from our clinical database with a follow-up of longer than 5 years. Clinical, demographic and biological factors associated with the development of disabling disease (according to predefined criteria) within 5 years after the diagnosis of CD and with the time to development of severe disease (according to predefined criteria) were successively studied by univariate and multivariate analyses. Results. The rate of disabling CD within 5 years after diagnosis was 57.9%. Perianal lesions, the need for steroids to treat the first flare and ileo-colonic location, but not age below 40 years were confirmed as predictive markers. The rate of severe disease was 37.4%. Stricturing behaviour (HR: 2.11 (95% CI: 1.39–3.20)) and loss of weight (>5kg) (HR: 1.67 (95% CI: 1.14–2.45)) at diagnosis were independently associated with the time to development of severe disease. The predictive performances of the models generated were low. Conclusions. Disabling and severe CD developed in roughly one-third and two-thirds of our patients, respectively. Some clinical predictive markers could be found or even confirmed but their performances were low.

Background: Crohn’s disease is a heterogeneous entity. Disease behaviour, characterised as stricturing, penetrating, or non-stricturing non-penetrating, is a clinically important phenotype as it is associated with complications and need for surgery. It has recently been showed that the behaviour of Crohn’s disease changes over the course of the disease. Aim: To assess the association between rapid development of a penetrating or stricturing pattern of Crohn’s disease and demographic and clinical characteristics as well as NOD2/CARD15 genotype. Patients and methods: A total of 163 patients with a firm diagnosis of Crohn’s disease and who had non-penetrating non-stricturing disease at diagnosis were studied. Various demographic and clinical characteristics as well as antisaccharomyces cerevisiae antibody status and NOD2/CARD15 genotype were documented in these patients. These characteristics were compared in subgroups of patients according to evolution of disease behaviour five years after diagnosis. Results: Five years after diagnosis there were 110 (67.5%) patients with non- structuring non-penetrating disease, 18 (11%) with stricturing disease, and 35 (21.5%) with penetrating disease. In multivariate analysis, only disease location and number of flares per year were significantly discriminant between the three subgroups (p=0.0009 and 0.0001, respectively). Ileal location of the disease was associated with a stricturing pattern while a high number of flares was associated with a penetrating pattern. Active smoking was also associated with a penetrating pattern compared with a non-stricturing non-penetrating pattern only. Conclusions: Early development of stricturing or penetrating behaviour in Crohn’s disease is influenced by disease location, clinical activity of the disease, and smoking habit, but not by NOD2/CARD15 genotype.

Pilot studies have shown good sensitivity and specificity for ¹⁸F-FDG PET in detecting gastrointestinal lesions of Crohn's disease. The combination of ¹⁸F-FDG PET with CT may further improve the localization and characterization of lesions with increased ¹⁸F-FDG uptake. Our aim was to assess the use of ¹⁸F-FDG PET/CT in evaluating the activity and location of Crohn's disease along the gastrointestinal tract. Methods: After giving informed consent, 22 patients with Crohn's disease were prospectively studied. They underwent ¹⁸F-FDG PET/CT, followed by ileocolonoscopy within 1 wk (mean, 2 d). The Crohn's disease activity index (CDAI) was calculated, and serum C-reactive protein (CRP) and fecal calprotectin were measured before endoscopy. The Crohn's disease endoscopy index of severity (CDEIS) was calculated during endoscopy. The global CDEIS score and endoscopic subscores for various ileocolonic segments were used for analysis. Results: Globally, 95 intestinal and colonic segments in 22 patients were analyzed. ¹⁸F-FDG PET/CT detected 35 of 48 endoscopically affected segments (sensitivity for the detection of endoscopic lesions, 72.9%). The sensitivity of ¹⁸F-FDG PET/CT for the detection of severe endoscopic lesions (deep ulcers and strictures) was 100% (14/14). The global PET/CT score significantly correlated with CDEIS (r = 0.51; 95% confidence interval [CI], 0.09–0.77; P = 0.017), CDAI (r = 0.58; 95% CI, 0.17–0.80; P = 0.005), and CRP (r = 0.56; 95% CI, 0.19–0.81; P = 0.007). Conclusion: ¹⁸F-FDG PET/CT was globally well correlated to the clinical, endoscopic, and biologic activity of Crohn's disease. Above all, this technique had a good sensitivity for the detection of intestinal and colonic segments with moderate to severe mucosal lesions. The potential impact of this promising tool on the global management of patients with Crohn's disease should be further evaluated in prospective studies.

Summary: Background: Women with inflammatory bowel diseases (IBD) often receive biologicals during pregnancy to maintain disease remission. Data on outcome of vedolizumab‐exposed pregnancies (VDZE) are sparse.Aims: To assess pregnancy and child outcomes of VDZE pregnancies and to compare these results to anti‐TNF exposed (TNFE) or both immunomodulatory and biologic unexposed (CON IBD) pregnancies.Methods: A retrospective multicentre case‐control observational study was performed.Results: VDZE group included 79 pregnancies in 73 IBD women. The TNFE and CON IBD group included 186 pregnancies (162 live births) in 164 IBD women and 184 pregnancies (163 live births) in 155 IBD women, respectively. At conception, cases more often had active disease ([VDZE: 36% vs TNFE: 17%, P = .002] and [VDZE: 36% vs CON IBD: 24%, P = .063]). No significant difference in miscarriage rates were found between groups (VDZE and TNFE: 16% vs 13%, P = .567; VDZE and CON IBD: 16% vs 10%, P = .216). In live‐born infants, median gestational age and birthweight were similar between groups. Median Apgar score at birth was numerically equal. Prematurity was similar in the VDZE group compared to the control groups, even when correcting for disease activity during pregnancy. The frequency of congenital anomalies was comparable between groups as were the percentages of breastfed babies. During the first year of life, no malignancies were reported and infants' infection risk did not significantly differ between groups.Conclusion: No new safety signal was detected in VDZE pregnancies although larger, prospective studies are required for confirmation.