Delineation of Crohn's Disease Trajectories Using Change in Lémann Index: A Natural History Study

Crohn's disease (CD) causes lifelong, progressive bowel damage, which may be quantified using the Lémann Index (LI). We aimed to analyze patterns of LI and its association with 5-year clinical course, in an independent cohort of CD patients.

CD patients with 5-year follow-up from a registry maintained at a tertiary center were included. LI was calculated using a computerized metric from the first (LI1) and last (LI2) clinical encounters during the 5 years. Groups were created based on change in score (LI2-LI1) or the delta Lémann Index (DLI) as showing improvement, no change, or deterioration and used for association analysis with patterns of health care utilization, disease activity, and quality-of-life scores.

A total of 363 CD patients with 5-year follow-up formed the study population [median age 43 y (interquartile range (IQR), 33.3 to 55 y); 57% female; median disease duration 12 y (IQR, 3 to 19 y), overall surgical exposure 69.7%]. Median (IQR) LI1, LI2, and DLI were 8 (0 to 54), 9 (0 to 75), and 0 (-22 to -47), respectively. Patients were stratified based on DLI into 3 groups: A: DLI<0; B: DLI=0; and C: DLI>0; which comprised 16.5%, 35.3%, and 48.2% of the cohort, respectively. Patients in group C had significantly higher CD-related surgical exposure, health care utilization, and annual use of steroids and biological agents. DLI showed independent significant positive correlation with perianal disease (P=0.044), steroid use (P=0.007), clinical visits (P<0.001), and new surgeries (P=0.001).

Change in LI over time could function as a marker of disease trajectory for risk substratification and prognostication in CD.