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New Index Measures Progression of Crohn's Disease
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Researchers have developed and validated the Lémann Index, the first comprehensive scoring system to assess cumulative structural bowel damage in Crohn’s disease.
“The Lémann Index we have developed is unique in that it takes into account both the extent and the depth of the damage all over the digestive tract and gives a global assessment of the digestive damage,” Jacques Cosnes, MD, from the gastroenterology and nutrition department at Hôpital Saint-Antoine in Paris, told Healio Gastroenterology. “By measuring the damage index at different time points in one individual we will be able to identify different phenotypes of the disease according to the speed of damage progression.”
Responding to the need for a scoring system that can better assess long-term effects of treatment strategies and cumulative structural bowel damage caused by CD over time — including stricturing lesions, penetrating lesions (fistulae and abscesses) and surgical resection — the International Program to Develop New Indexes in Crohn’s Disease (IPNIC) group performed an international, prospective, cross-sectional, observational study from August 2008 to December 2010. In the construction phase, investigators analyzed data from 138 patients from 12 centers stratified by disease duration and location (24 upper tract, 115 small bowel, 92 colon/rectum and 59 anus); these locations were further divided into segments for the purposes of developing this index.
All patients underwent clinical examination and abdominal MRI while upper endoscopy, colonoscopy and pelvic MRI were performed based on disease location. Surgical procedures, predefined strictures and/or penetrating lesions were graded on a 3-point severity scale. For each segment, damage was measured from zero (no damage) to 10 (maximal damage/complete resection), taking strictures and penetrating lesions into account. Overall organ damage was calculated using averages of segmental damage, and a global damage evaluation was provided on a 10-point scale using calculated organ damage evaluations. Predicted organ indexes and Lémann Index were then developed using a multiple linear mixed model.
Validation demonstrated the unbiased correlation coefficients between predicted indexes, and investigator damage evaluations were 0.85 for upper tract, 0.98 for small bowel, 0.9 for colon/rectum, 0.82 for anus and 0.84 overall. Median Lémann Index also increased with disease duration (P<.001).
“We know now that what is important for the long term is not to control symptoms but to control anatomical lesions,” Cosnes said. “An important point will be to identify in the short-term patients who progress rapidly to a significant damage. If we can identify those patients during the first few months following diagnosis, we can treat them aggressively with the more potent drugs (biologics) having the objective to delay or avoid surgery. Conversely, patients who do not develop [significant] damage or who do not progress may be treated with more classical drugs.”
Stephen B. Hanauer
In an accompanying editorial, Ashwin N. Ananthakrishnan, MD, from Massachusetts General Hospital and Harvard Medical School, and Stephen B. Hanauer, MD, from the Feinberg School of Medicine at Northwestern University, wrote that, “The time is ripe for the implementation of indices that measure cumulative bowel damage, truly the most important measure, for progressive diseases.” However, although the Lémann Index may be a strong first step toward that goal, “much additional efforts and financial support are needed to move forward to address the unresolved practical and technical issues related to the reproducibility and validation of the index.” These issues include validation in an independent inflammatory bowel disease cohort, variability in interpretation and availability of abdominal MRI in the wider community, and “lack of a reliable ‘gold standard’ clinical or patient-reported comparator,” they wrote.
For more information:
Ashwin NA. Gastroenterology. 2015;148:8-19.
Pariente B. Gastroenterology. 2015;148:52-63.
Disclosure: Cosnes received consultancy fees from AbbVie. See the study for a full list of the other researchers’ financial disclosures. Ashwin and Hanauer report no relevant financial disclosures.