Proximal Small Bowel Crohn’s Disease is Associated With More Severe Injury and Need for Treatment With Biologics

Background: Crohn’s disease (CD) is heterogeneous, and proximal involvement in the small bowel (SB) is associated with worse outcomes. Nonetheless, studies on the impact of duodenal and jejunal lesions in SB CD are limited. This study aimed to investigate the clinical characteristics and outcomes of individuals diagnosed with SB CD, comparing those with and without proximal inflammation. Methods: A cohort of 53 treatment-naive SB CD patients that underwent capsule endoscopy at diagnosis were retrospectively selected. The inflammatory activity was quantified using the Lewis Score (LS) for each SB tertile. Exclusion criteria encompassed colonic involvement, stricturing, and fistulizing phenotypes. The follow-up period averaged five years. Results: Thirty-seven (69.8%) patients displayed inflammatory activity in the first and/or second tertile together with third tertile involvement (proximal+T3 group). Sixteen (30.2%) had inflammation in the third tertile only (T3 group). The LS accounts for the SB tertile with the highest degree of inflammation, yet we found that individuals with CD lesions in the proximal SB segments had a higher risk for moderate to severe inflammation (OR 4.93, 95% CI: 1.3-18.3, p=0.013). A subgroup analysis for those with mild inflammatory activity, in which treatment guidelines are less clear, was performed. There were no demographic or clinical differences at baseline between the Proximal+T3 and T3 groups. Notably, individuals with mild disease in the Proximal+T3 group initiated biologic drugs more often (OR 11, 95% CI: 1.1-109.7, p=0.036). Conclusions: Proximal small bowel lesions are associated with increased inflammatory activity, necessitating more frequent use of biologics in patients with mild disease. Early detection of proximal SB CD with capsule endoscopy may contribute to timely treatment.