Prognostic Factors for the Efficacy of Infliximab in Patients with Luminal Fistulizing Crohn's Disease

Background: Enteric fistula is one of the penetrating features in Crohn's disease (CD). This study aimed to clarify the prognostic factors for the efficacy of infliximab (IFX) treatment in luminal fistulizing CD patients.

Methods: We retrospectively included 26 cases diagnosed with luminal fistulizing CD hospitalized in our medical center from 2013 to 2021. The primary outcome of our research was defined as death from all causes and undergoing of any relevant abdominal surgery. Kaplan-Meier survival curves were used to describe overall survival. Univariate and multivariate analyses were used to identify prognostic factors. A predictive model was constructed using Cox proportional hazard model.

Results: The median follow-up time was 17.5 months (range 6-124 months). The 1- and 2-year surgery-free survival rates were 68.1% and 63.2%, respectively. In the univariate analysis, the efficacy of IFX treatment at 6 months after initiation (P < 0.001, HR 0.23, 95% CI 0.01-0.72) and the existence of complex fistula (P = 0.047, HR 4.11, 95% CI 1.01-16.71) was found significantly related to the overall surgery-free survival, while disease activity at baseline (P = 0.099) also showed predictive potential. The multivariate analysis showed that efficacy at 6 months (P = 0.010) was an independent prognostic factor. The C-index of the model for surgery-free survival was 0.923 (P < 0.001), indicating an acceptable predictive effect.

Conclusion: Prognostic model including the existence of complex fistula, disease activity at baseline and efficacy of IFX at 6 months may be useful to predict long-term outcome of luminal fistulizing CD patients.