Bowel damage and its correlation with the disability index in patients with recently diagnosed Crohn´s Disease

Background: Crohn’s disease (CD) progression can lead to bowel damage (BD) and disability. However, the longitudinal characterization of BD and
disability in early CD patients remains limited.
Methods: The Crohn´s Disease Cohort (CROCO) is a multicentre, European cohort study of newly diagnosed CD patients (<12 months following
diagnosis) intended to prospectively characterize BD progression and disability. At one year following inclusion (Y1), BD progression was evaluated
using the Lémann Index (LI). Magnetic resonance enterography was completed by all patients, with additional endoscopy and/or pelvic MRI
based on disease location. Absence of BD was defined as a LI=0, and any presence of bowel damage was indicated by LI>0. Disability was assessed
using the validated IBD-disability index (IBD-DI) encompassing various domains. We report the LI at Y1 and its association with significant disease
features and with the IBD-DI.
Results: Among the 261 included patients, 135 have completed the Y1 visit, with 100 having their LI calculated [57% male, median age at diagnosis
of 36 years old (IQR 26-48)]. Most patients (90%) had ileal or ileocolonic involvement, 68% had inflammatory phenotype, and 11% had perianal
disease. At inclusion, 7% of patients had undergone surgery (5 intestinal and 2 perianal), and 53% had initiated biological therapy within the first
year of disease, primarily anti-TNF in mono or combination therapy. Of those with stricturing (B2) or penetrating (B3) behaviour, 77% and 79%,
respectively, were on anti-TNF therapy. Overall, 61% of the patients exhibited some degree of BD (LI>0), yet the median LI at Y1 was low [0.6
(IQR 0-2)]. Univariate analysis revealed an association between the presence of any bowel damage at Y1 and disease behaviour at inclusion (B2
OR 3.33, 95%CI 0.84-13.18 and B3 OR 8.5, 95%CI 1.82, 39.66; p<0.01). Additionally, there was a significant association with anti-TNF therapy
(OR 2.88, 95%CI 1.24-6.66, p=0.012). In a multivariate logistic model, only older age at diagnosis appeared protective against any BD (Table 1).
Among those evaluated for the LI, 84 completed the IBD-DI at Y1. The median IBD-DI was 17.3 (IQR 10.7-32.6) and 30% experienced moderateto-
severe disability (IBD-DI>35). No association was observed between LI and IBD-DI at Y1 (OR 1.09, 95%CI 0.39-3.04, p=0.86) and there were
no differences in the median LI across disability categories (p=0.67) (Figure 1).
Conclusion: In a cohort of newly diagnosed CD patients, one-third exhibited no bowel damage as per the LI evaluation. For those presenting any
degree of damage, the global LI remained low. No association was found with disability assessed by the IBD-DI. These data add to the growing
concept that early disease represents a window of opportunity.