Mucosal healing might alter midterm and long-term outcomes of patients with Crohn's disease (CD) and has become an important end point in clinical trials.
However, the minimal degree of mucosal improvement (endoscopic response) required to alter midterm outcomes is not known.
Dr Marc Ferrante and colleagues from Belgium determined the best definition of endoscopic response by evaluating data on the Simple Endoscopic Score for Crohn's Disease (SES-CD), and the Crohn's Disease Endoscopic Index of Severity (CDEIS) from the Study of Biologic and Immunomodulator Naive Patients in Crohn's Disease (SONIC trial).
The researchers analyzed data from 172 patients who participated in the SONIC trial, were found to have endoscopic lesions at baseline, and underwent a second endoscopic examination at week 26 of treatment with infliximab, azathioprine, or both.
The team defined mucosal healing as absence of ulcers.
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A central reader calculated SES-CD and CDEIS results.
Different cutoff values were set for endoscopic response based on the SES-CD or CDEIS.
The diagnostic ability of these different cutoff values was evaluated using receiver operating characteristic curves, positive likelihood ratios, and negative likelihood ratios.
Corticosteroid-free clinical remission (CFREM) at week 50 was used as a binary classifier.
Based on analyses of ROC curves, positive likelihood ratios, and negative likelihood ratios, endoscopic response was defined as a decrease from baseline in SES-CD of at least 50%.
The research team found that at week 26, mucosal healing and endoscopic response were achieved in 48% and 65% of patients, respectively.
Mucosal healing at week 26 was associated with CFREM at week 50, with 56% sensitivity, 65% specificity, a positive likelihood ratios of 1.60, and an negative likelihood ratios of 0.67.
Endoscopic response at week 26 was associated with CFREM at week 50, with 74% sensitivity, 48% specificity, a positive likelihood ratios of 1.42, and an negative likelihood ratios of 0.54.
The team observed that endoscopic response, defined as a decrease from baseline in CDEIS of at least 50%, yielded similar results.
Dr Ferrante's team concludes, "In patients with Crohn's disease, mucosal healing and endoscopic response at week 26 of treatment identified those most likely to be in CFREM at week 50."
"The ability of the proposed endoscopic response cutoff value to predict midterm CFREM should be validated in an independent, prospective cohort."
"Its correlation with changes in long-term disease progression still needs to be demonstration."