Terminal Ileum Thickness During Maintenance Therapy Is a Predictive Marker of the Outcome of Infliximab Therapy in Crohn Disease.

Background: Mucosal healing has been associated with long-term response to therapy for Crohn disease (CD). However, little is known about the significance of terminal ileum (TI) transmural thickness in predicting clinical outcomes.
Methods: In this retrospective observational cohort study, we examined the association of an index ultrasonographic assessment of TI thickness during the maintenance phase and the subsequent clinical outcome of CD in a cohort of patients treated with infliximab (IFX). Treatment failure was defined as treatment discontinuation because of lack of efficacy, a need for dose escalation, or surgery. Clinical response was defined as treatment continuation in the absence of any of the aforementioned failure criteria.
Results: Sixty patients with CD receiving IFX therapy were included in the study. The patients were followed for a median of 16 months (5-24 months) after an index intestinal ultrasound. Thirty-eight patients (63.3%) maintained response to the therapy and 22 patients (36.6%) failed the treatment, with a mean follow up of 10.5 months (6.5-17 months) vs 9.25 months (1-10.25 months), respectively. On univariate analysis, the only variables differing between treatment response and failure were a TI thickness of 2.8 vs 5 mm (P < 0.0001) and an IFX trough level of 6.6 vs 3.9 µg/mL (P = 0.008).On multivariable analysis, only a small bowel thickness of ≥4 mm was associated with the risk of treatment failure (odds ratio, 2.9; 95% CI, 1.49-5.55; P = 0.002).
Conclusions: Our findings suggest that transmural thickness of ≥4 mm can predict subsequent treatment failure in patients with CD treated using IFX, indicating transmural thickness <4 mm as a potential novel valuable therapeutic target.
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