Lemann Index for Assessment of Crohn's Disease: Correlation with the Quality of Life, Endoscopic Disease Activity, Magnetic Resonance Index of Activity and C- Reactive Protein

Changes Over Time in the Lémann Index and the Inflammatory Bowel Disease Disability Index in a Prospective Cohort of Patients With Crohn's Disease

BACKGROUND

Crohn's disease (CD) is a progressive, destructive, and disabling disorder. Our study aimed to assess changes over time in the Lémann index (LI) and the Inflammatory Bowel Disease Disability Index (IBD-DI) in a cohort of CD patients.

METHODS

This was a single-center prospective cohort study of 130 consecutive CD patients with a follow-up of at least 4 years. The LI 1 and the IBD-DI 1 questionnaires were assessed in 2016 and again between September 2020 and October 2021 (LI 2 and IBD-DI 2).

RESULTS

Of the 130 patients with assessment of both LI 1 and IBD-DI 1, 61 had calculation of the LI 2 and 98 patients answered the IBD-DI 2 questionnaire, with a median time between the 2 evaluations of 4.2 years. The LI increased for 16 (26%), decreased for 26 (43%), and remained unchanged for 19 (31%) patients. The median LI did not change over time (9.6 vs 9.3; P = .14). Clinical disease activity was significantly associated with bowel damage progression. A high initial LI (>7.9) was not associated with CD progression (surgery, drug dose escalation, or change of biologic). The IBD-DI decreased for 59 (60.2%), increased for 37 (37.8%), and remained unchanged for 2 (2%) patients. The median IBD-DI decreased significantly over time (23.2 vs 21.4; P = .006). There was no correlation between the 2 indexes.

CONCLUSIONS

This is the first prospective cohort study assessing changes over time in both the LI and the IBD-DI in CD patients. After 4 years, the LI appeared to be stable and the IBD-DI decreased, with no correlation between the 2 indexes.

Prospective Validation of the Lémann Index in Children: A Report From the Multicentre Image Kids Study

BACKGROUND

The Lémann Index [LI] and the recently updated LI are tools for measuring structural bowel damage in adults with Crohn's disease [CD] but have not been evaluated in children. We aimed to validate the updated LI in the prospective multicentre ImageKids study of paediatric CD.

METHODS

We included children with CD undergoing magnetic resonance enterography [MRE], pelvic magnetic resonance imaging [MRI] and ileocolonoscopy. Half were followed for 18 months, when MRE was repeated. Serum was collected for fibrosis-related proteomic markers. The LI was calculated by central readers from the MRE, ileocolonoscopy, physical examination and surgical data. Reliability and construct validity were assessed at baseline, while responsiveness and test-retest reliability were explored longitudinally.

RESULTS

In total, 240 children were included (mean age, 14.2 ± 2.5 years; median disease duration, 2.2 years [interquartile range, IQR 0.25-4.42]; median baseline LI, 4.23 [IQR 2.0-8.8]). The updated LI had excellent inter-observer reliability (interclass correlation coefficient [ICC] = 0.94, 95% confidence interval [CI] 0.92-0.95) but poor, although statistically significant, correlation with radiologist and gastroenterologist global assessments of damage and with serum proteomic levels of fibrotic markers [rho = 0.15-0.30, most p < 0.05]. The updated LI had low discriminative validity for detecting damage (area under the receiver operating characteristic curve [AUC-ROC] 0.69, 95% CI 0.62-0.75). In 116 repeated MREs, responsiveness was suboptimal for differentiating improved from unchanged disease [AUC-ROC 0.58, 95% CI 0.45-0.71]. Test-retest reliability was high among stable patients [ICC = 0.84, 95% CI 0.72-0.91].

CONCLUSION

Overall, the updated LI had insufficient psychometric performance for recommending its use in children. An age-specific index may be needed for children with shorter disease duration than typical adult cohorts.

Diagnosis and natural history of preclinical and early inflammatory bowel disease

Inflammatory bowel disease is a chronic and progressive disorder of the gastrointestinal tract. A relevant proportion of patients develop complicated lesions, defined as strictures, fistulas and/or abscesses already at diagnosis, and this proportion increases over time. The preclinical phase defines the period of time from the appearance of the first immune disturbances until the development of overt disease, and it may be present months to years before the diagnosis. Multiple biomarkers (e.g., C-reactive protein, interleukin-6, fecal calprotectin) and cellular mechanisms (e.g., complement cascade, lysosomes, innate immunity, and glycosaminoglycan metabolism) are already altered during this period. Research in this area allows the description of the initial immune disturbances that may identify potential targets and lead to the development of new drug therapies. During this period, different interventions in high-risk individuals, including drugs or environmental factors, will open the possibility of innovative strategies focused on the reduction of complications, or even prevention trials for inflammatory bowel disease. Here, we review the most relevant findings regarding the characteristics, prevalence and biomarkers associated with preclinical disease, along with their possible use in our future clinical practice.

Impact of therapies on bowel damage in Crohn's disease

Crohn's disease (CD) is a chronic inflammatory bowel disease that usually progresses to bowel damage, defined as strictures, fistulas and abscesses. These complications require intestinal resection and lead to further irreversible structural damage. Cross-sectional imaging, such as magnetic resonance imaging, computed tomography and ultrasound, are accurate in assessing intestinal damage at a definite time point and the progression of damage over time. Recently, an imaging-based index, the Lémann Index, has been proposed and developed in order to quantify bowel damage in CD patients; emerging data confirm that this Index can measure the structural damage with good sensitivity to change. One challenge remains to understand whether existing or future treatments might be able to stop bowel-damage progression or even reverse intestinal damage, improving the prognosis and changing the natural history of CD. We reviewed the current data available in the literature focused on the measure of structural damage in CD patients, mainly focusing on the impact on therapies in reversing bowel damage. We also explored some further perspectives on measuring and targeting intestinal damage in clinical research and in clinical practice as an ultimate therapeutic target.