Experts have established a severity index for inflammatory bowel disease (IBD), according to results of an analysis published in the journal Gut (doi: 10.1136/gutjnl-2016-312648). The index, conceived by a panel of IBD specialists from the International Organization for the Study of Inflammatory Bowel Diseases, is a step toward the standardization of disease severity definitions in ulcerative colitis and Crohn’s disease.
The panel determined 16 severity attributes for Crohn’s disease and 13 for ulcerative colitis. The analysis found that, in Crohn’s disease, mucosal lesions, fistulas, and abscesses were the greatest contributors to disease severity at 15.8%, 10.9%, and 9.7%, respectively. In ulcerative colitis, 18.1% of disease severity was attributed to mucosal lesions, 14% to impact on daily activities, and 11.2% to C-reactive protein, wrote Corey A. Siegel, MD , MS, of the Dartmouth-Hitchcock Medical Center in Lebanon, N.H., and his coauthors.
Investigators used a PubMed literature search to identify three broad elements of disease severity: impact of disease symptoms on daily activities, inflammatory burden, and disease course. A panel of 16 experts then conducted a series of votes to determine which attributes within each domain would be used to assess disease severity. Two sets of attributes were defined as disease markers in Crohn’s disease and ulcerative colitis.
A type of conjoint analysis called adaptive choice-based conjoint was then performed to ascertain how different clinical factors influenced specialists’ decision making and impressions of disease severity. A series of questions was asked, with each response determining subsequent questions, until “ample consistency” was found in their choices.
The exercise first had participants decide which hypothetical patient profiles met their evaluation criteria; it then showed them two final profiles and asked which was the more severe case. Survey length depended on the consistency of participants’ responses, with those lacking consistency being given more tasks to complete, Dr. Siegel and his colleagues reported.
Respondents completed the exercise three times: first independently without discussion, then after discussion in a group setting with an automated response system, and finally, independently following group discussion. Disease severity indexes were created on a 100-point scale, and average part-worth utility scores were used to determine minimum and maximum scores for each attribute, with zero representing the absence of a symptom.
Crohn’s disease severity was largely dependent on factors related to intestinal damage, whereas ulcerative colitis disease severity was associated with symptoms and effects on daily life.
This analysis “helps redefine overall disease severity for IBD,” the authors wrote. Once validated, the indexes will offer “both further research opportunities and a practical tool by which to classify overall disease severity of patients and offer appropriate treatment without relying on present symptoms alone,” they added.
Dr. Siegel and colleagues noted that future studies should focus on prospective validation of the disease indexes in different patient populations, as well as conducting a conjoint analysis with patients.
“We expect this work to begin to address a change in how we think about patients with IBD and how to identify those at the higher end of the risk spectrum so that appropriate intensive treatment can be initiated and optimized in an efficient, precise, and cost effective manner,” they concluded.
The study was funded by AbbVie and Tillotts Pharma. The authors disclosed financial relationships with numerous additional pharmaceutical companies.
SOURCE: Siegel CA et al. Gut. 2018 Feb;67(2):244-54.