Histopathologic scores unreliable for fibromuscular stenosis in CD

By Marilynn Larkin

NEW YORK (Reuters Health) - 9/9/2019

Available histologic scoring systems to assess small bowel fibrosis in Crohn's disease (CD) have not been validated or tested for reliability, a systematic review reveals. A new scoring system is currently in development.

"This article for the first time systematically summarizes what histopathologic scoring systems have been used in the area of small bowel intestinal fibrostenosis in CD," Dr. Florian Rieder of the Cleveland Clinic Foundation in Ohio told Reuters Health by email. "The take-home message for clinicians is that...none of them are validated or have been properly developed. The intestinal muscle constitutes a critical component of the stricture in CD."

"We already completed a RAND/UCLA (assessment) (http://bit.ly/2LELUlv) to weigh all the different scoring items we found in this article based on their appropriateness to be included into a new score," he said. "In parallel, we are preparing central (endoscopy) reading exercises to develop a novel index that considers all the items published in the article."

Dr. Rieder and colleagues searched the literature through March 13, 2019. "In brief," they write, "the inclusion criteria for this systematic review were solely full thickness small bowel histopathology, which used a histologic scoring system to characterize small bowel CD assessing inflammatory as well as fibrotic alterations within the same (adult) subject."

"All scores fitting the criteria were included in our analysis," they note, "independently of the presence of stricturing disease, as long as inflammation and fibrosis were evaluated separately but in the same scoring system."

As reported online August 30 in Gastroenterology, the team found "substantial heterogeneity among scoring systems, which were not derived using modern principles for evaluative index development."

None of the systems had undergone formal validity or reliability testing, nor had they been constructed according to accepted methods for development of evaluative indices.

Further, basic knowledge regarding the systems' operating properties was lacking.

The authors conclude, "Data that describe the operating properties of existing cross-sectional imaging techniques for stenosing CD should be questioned. Development and validation of a histopathology index is an important research priority."

Dr. Rieder added, "There are multiple more initiatives ongoing under the umbrella of the Stenosis Therapy and Research (STAR) consortium, all with the goal to build a pathway that allows testing of novel anti-stricture therapies in IBD...We are developing a patient-reported outcome tool and a stricture radiology index and validating them."

Dr. David Binion, Co-Director of the IBD Center at UPMC in Pennsylvania, commented by email, "We are in need of a structured approach to systematically characterize, describe and quantify strictures in CD, which will provide a foundation for assessing efficacy of anti-fibrotic agents which are in development. The authors...have clearly demonstrated that an adequate 'measuring stick' to assess cellular and acellular components of bowel wall fibrosis does not exist at this time."

"They have made a compelling case for a new index which can reliably and reproducibly address inflammation, fibrosis and myofibroblast hypertrophy/hyperplasia in specific anatomic components of the bowel wall," he told Reuters Health. "Only after such an index is created can effective clinical investigation of anti-fibrotic agents for medical therapy of CD small bowel strictures move forward."

"The new index...is in development at this time," he said. "Therefore, we are eagerly awaiting the arrival of this tool for research trials, and potentially to help determine histologic features identifying individuals who might be of highest risk for repeat stenosis and repeat surgery."

SOURCE: http://bit.ly/2LIAn4L

Gastroenterol 2019.

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