ABSTRACT
BACKGROUND AND STUDY AIMS: Isolated small bowel Crohn's disease (SBCD) is reported to have a worse prognosis compared to other CD phenotypes. The aim of this study was to understand the correlation between Isolated SBCD and ileocolonic disease with blood and faecal biomarkers and also to identify differences in outcome and management between the two phenotypes. PATIENTS AND METHODS: Patients with ileocolonic or isolated small bowel Crohn's Disease (SBCD) were identified from an existing capsule endoscopy (CE) database. Harvey Bradshaw Index (HBI), biomarkers: c-reactive protein (CRP) and faecal calprotectin (FC), Lewis score and findings on CE and subsequent follow up data were collected. SPSS was used to analyse the data. RESULTS: In total 248 patients were included in the study. Patients were split into two groups- Isolated SBCD with 178 patient (median age 44 years (IQR 31-56); 41.5 % male) and Ileocolonic Crohn's with 70 patients (median age 31 years (IQR 22.7-49); 31.5 % male). A new diagnosis of SBCD was made in 38.7 % (n = 96), whilst 60.0 % (n = 144) had established CD. Patients with ileocolonic disease had a higher HBI in comparison to isolated SBCD [HBI = 7 (IQR 5-10) vs HBI = 6(IQR 4-9); P = 0.04 ]. There was no significant difference in the FC levels between isolated SBCD and ileocolonic disease [136ug/g (IQR 53.8-363.3) vs 171ug/g (IQR 68.5-485.5); p = 0.98]. In isolated SBCD group, 30.3 % (n = 54) CE showed proximal disease, 96 % (n = 171) showed distal disease and 26.4 % (n = 47) showed extensive disease. SBCE was superior to MRI at diagnosing proximal SBCD (P < 0.01). On multivariate logistic regression, we did not identify any predictors of disease severity defined as Lewis score > 790. Following SBCE, 68.5 % (n = 170) of the total patients had a management change. This included commencement or dose escalation of corticosteroids in 123 (49.5 %) patients, azathioprine in 80 (33.3 %) patients, methotrexate in 22 (9.1 %) patients and biological therapy in 110 (44.3 %) patients. HBI predicted a change in management (p < 0.01). CONCLUSION: CE is an important modality for the diagnosis of active SBCD. It also helps guide treatment in patients identified with active disease.
