Lemann Index for Assessing Bowel Damage in Crohn’s Disease: A Real-world Study

Abstract

Abstract Background and Aims The Lemann Index [LI], an endpoint to measure cumulative structural bowel damage in Crohn’s disease [CD], has been recently updated and validated. We applied this to investigate predictors of bowel damage in a real-world cohort. Methods We performed a retrospective study [2008–2022] involving two tertiary referral IBD centres in the USA. Magnetic resonance imaging [MR] or computed tomography [CT] enterographies were reviewed by study radiologists with endoscopy reports by study gastroenterologists, to calculate LI scores. Baseline and follow-up LI scores were calculated. We defined high bowel damage as LI ≥ 2. Factors associated with high LI were identified in patients with ≥ 2 LI scores, using multivariate logistic regression, and then assessed for a change in LI [increase vs no change/decrease], using a multivariate linear mixed-effects model. Results A total of 447 patients with CD had a median first LI of 7 (interquartile range [IQR], 1.25–14.55). Median LI scores were significantly different when categorised by disease duration; 2.0 [IQR, 0.6–5.9] for < 2 years, 2.6 [IQR, 0.6–9.6] for ≥ 2 and < 10 years, and 12.5 [IQR, 6.4–21.5] for ≥ 10 years, with a p < 0.01. Disease duration, presence of perianal disease, elevated C-reactive protein, and Harvey–Bradshaw index, were associated with a high LI at inclusion and increase in LI during follow-up [all p < 0.01]. Conclusions The updated LI quantified cross-sectional and longitudinal cumulative bowel damage in a real-world cohort of patients with CD, with predictors identified for a longitudinal increase in LI. Further studies for prospective validation of LI and identification of multi-omic predictors of bowel damage are needed.