P411 Is transmural healing better than mucosal healing in pediatric Crohn’s disease?

Abstract

Abstract Background While the long-term benefit of achieving mucosal healing (MH) in Crohn’s disease (CD) has been demonstrated, data on transmural healing (TH), assessed by non-invasive imaging modalities (i.e. magnetic resonance enterography, MRE) are scarce, particularly in the pediatric setting. Nonetheless it has been deemed as an adjunctive target for CD by the STRIDEII consensus. We aimed to investigate the outcomes of pediatric CD patients with TH comparing them to those with MH and with “no healing”. Methods Prospective, single-center, observational study conducted at the Pediatric Gastroenterology and Liver Unit of the Umberto I Hospital, Sapienza University of Rome. Children with an established diagnosis of CD and under biological therapy undergoing an MRE and an ileocolonoscopy performed within a 3-month interval were consecutively enrolled. Transmural healing was defined as the complete healing of both the mucosa at endoscopy (absence of ulceration) and of the bowel layers at the MRE. In the presence of a normal colonoscopy but an active MRE children were deemed as MH. The group “no healing” (NH) included children with an active endoscopy, regardless of the MRE classification. At 6, 12, and 24 months, the following outcomes were evaluated and compared in the three groups: disease flares, CD-related hospitalization, CD-related surgery, need for step-up treatment, and occurrence of complications. Results 93 children were included (30% female, mean age 11,2±3,8). Twenty-three (25%) were classified as TH, 27 (29%) as MH and 43 (46%) as NH. Overall, at the Kaplan Meier analysis, the risk of any unfavorable outcome was significantly lower in both TH and MH patients compared to NH (Log Rank p<0.0001 and p=0.002, respectively). Specifically, children with TH were at lower risk of hospitalization (p=0.02), and complications (p=0.007) compared to those with NH. No difference was found between MH and NH children for the same outcomes. Both TH and MH children were at lower risk of step-up treatment (p<0.0001 and p=0.0.0002, respectively) compared to NH. No difference was found between TH and MH patients for all the outcomes evaluated. Conclusion Achieving transmural healing in pediatric CD is associated with better long-term outcomes, although the additional benefit compared to reaching MH alone does not appear significant. However, the persistence of inflammation is associated with worse outcomes in all patients.