Bowel Damage in Patients With Long-term Crohn's Disease, Assessed by Magnetic Resonance Enterography and the Lémann Index

Abstract

Background & aims: Magnetic resonance enterography (MRE) is used to evaluate the extent and complications of Crohn's disease (CD). MRE results are used in calculation of the Lémann index (LI) score, which quantifies bowel damage. The long-term outcomes of CD are uncertain; we aimed to assess bowel disease and damage in patients with CD for 20 years using MRE and the LI.

Methods: We performed a follow-up analysis of a population-based cohort of 237 patients in southeastern Norway diagnosed with CD from 1990 to 1993. Twenty years after diagnosis, 156 attended the evaluation in which they were offered routine clinical blood tests and colonoscopies. Ninety-six patients were examined by MRE and LI scores were calculated. The independent association of the LI score with clinical variables was examined by univariate analysis.

Results: Sixty-five patients (67.7%) had CD manifestations based on findings from MRE (36.9%), colonoscopy (29.2%), or both (33.9%). MRE findings changed disease classification for 8 patients (8.3%). The median LI score was 4.6 (interquartile range, 17.5) and associated with younger age (P = .02), complicated ileocolonic phenotype (P < .001), and use of biologic (P < .001), or immunosuppressant therapies (P = .045). Factors independently associated with LI score during the follow-up period were age, complicated disease, use of medication, and markers of inflammation.

Conclusions: In a population-based study of 237 patients with CD in Norway, we found that almost 68% had imaging features of CD, half of which were only detectable by MRE. LI score associated with ongoing active disease. Young age, complicated disease, and persistent inflammation were associated with bowel damage.

Keywords: Epidemiology; IBD; Inflammatory bowel disease; Radiology.