Validation and update of the Lémann index to measure cumulative structural bowel damage in Crohn's disease.

BACKGROUND The Lémann index is a tool measuring cumulative structural bowel damage in Crohn's disease (CD). We here report its validation and updating. METHODS This was an international, multicenter, prospective, cross-sectional observational study. At each center, 10 inclusions, stratified by CD duration and location, were planned. For each patient, the digestive tract was divided into 4 organs, upper tract, small bowel, colon/rectum, anus, and subsequently into segments, explored systematically by magnetic resonance imaging (MRI), and by endoscopies in relation to disease location. For each segment, investigators retrieved information on previous surgical procedures, identified predefined strictures and penetrating lesions of maximal severity (grades 1-3) at each organ investigational method (gastroenterologist and radiologist for MRI), provided segmental damage evaluation ranging from 0.0 to 10.0 (complete resection). Organ resection-free cumulative damage evaluation was then calculated from the sum of segmental damages. Then, investigators provided a 0-10 global damage evaluation from the 4 organ standardized cumulative damage evaluations. Simple linear regressions of investigator damage evaluations on their corresponding Lémann index were studied, as well as calibration plots. Finally, updated Lémann index was derived through multiple linear mixed models applied to combined development and validation samples. RESULTS In 15 centers, 134 patients were included. Correlation coefficients between investigator damage evaluations and Lémann indexes were above 0.80. When analyzing data in 272 patients from both samples and 27 centers, the unbiased correlation estimates were 0.89, 0,97, 0,94, 0.81, 0.91 for the 4 organs and globally, and stable when applied to one sample or the other. CONCLUSIONS The updated Lémann index is a well-established index to assess cumulative bowel damage in Crohn's disease that can be used in epidemiological studies and disease modification trials.

[1]  S. Ng,et al.  Selecting Endpoints for Disease-Modification Trials in Inflammatory Bowel Disease: the SPIRIT consensus from the IOIBD. , 2021, Gastroenterology.

[2]  D. Altman,et al.  The Impact of Clinical Information on the Assessment of Endoscopic Activity: Characteristics of the Ulcerative Colitis Endoscopic Index Of Severity [UCEIS] , 2015, Journal of Crohn's & colitis.

[3]  D. Altman,et al.  Reliability and initial validation of the ulcerative colitis endoscopic index of severity. , 2013, Gastroenterology.

[4]  E. Louis,et al.  Evolving Definitions of Remission in Crohn’s Disease , 2013, Inflammatory bowel diseases.

[5]  L. Peyrin-Biroulet,et al.  Moving towards disease modification in inflammatory bowel disease therapy , 2013, Current opinion in gastroenterology.

[6]  Jordi Rimola,et al.  Magnetic resonance imaging for evaluation of Crohn's disease: Validation of parameters of severity and quantitative index of activity , 2011, Inflammatory bowel diseases.

[7]  H. Tilg,et al.  Development of the Crohn's disease digestive damage score, the Lémann score , 2010, Inflammatory bowel diseases.

[8]  L. Peyrin-Biroulet,et al.  The Natural History of Adult Crohn's Disease in Population-Based Cohorts , 2010, The American Journal of Gastroenterology.

[9]  C.J.H. Mann,et al.  Clinical Prediction Models: A Practical Approach to Development, Validation and Updating , 2009 .

[10]  P. Rutgeerts,et al.  Development and validation of a new, simplified endoscopic activity score for Crohn's disease: the SES-CD. , 2004, Gastrointestinal endoscopy.

[11]  R. Xu.  Measuring explained variation in linear mixed effects models , 2003, Statistics in medicine.

[12]  Sunil J Rao,et al.  Regression Modeling Strategies: With Applications to Linear Models, Logistic Regression, and Survival Analysis , 2003 .

[13]  P. Rutgeerts,et al.  A review of activity indices and efficacy endpoints for clinical trials of medical therapy in adults with Crohn's disease. , 2002, Gastroenterology.

[14]  V. Carey,et al.  Mixed-Effects Models in S and S-Plus , 2001 .

[15]  J Y Mary,et al.  Development and validation of an endoscopic index of the severity for Crohn's disease: a prospective multicentre study. Groupe d'Etudes Thérapeutiques des Affections Inflammatoires du Tube Digestif (GETAID). , 1989, Gut.

[16]  Uma Mahadevan,et al.  Inflammatory Bowel Disease 2017: Innovations and Changing Paradigms. , 2017, Gastroenterology.

[17]  E. Louis,et al.  Development of the Lémann index to assess digestive tract damage in patients with Crohn's disease. , 2015, Gastroenterology.

[18]  M. Picco,et al.  Magnetic resonance for assessment of disease activity and severity in ileocolonic Crohn's disease , 2010 .

[19]  Y Vergouwe,et al.  Updating methods improved the performance of a clinical prediction model in new patients. , 2008, Journal of clinical epidemiology.

[20]  Province,et al.  Development and validation of an endoscopic index of the severity for Crohn's disease: a prospective multicentre study. Groupe d'Etudes Thérapeutiques des Affections Inflammatoires du Tube Digestif (GETAID). , 1989, Gut.