Background and aims: Serum infliximab trough level(S-IFX) and antibody were documented to correlate with clinical response. The aim of this study was to identify the relationship between early S-IFX, early mucosal healing (MH) and one-year outcome in a cohort on maintenance IFX therapy in Crohn's disease (CD).
Methods: The study group comprised of retrospectively enrolled patients diagnosed for Crohn's disease (n = 108). Patients received scheduled maintenance therapy after response to IFX induction, and had undergone the early S-IFX test and endoscopic examination at week 14. Clinical outcomes were evaluated during maintenance therapy until week 52.
Results: Early S-IFX was 4.78 ± 6.16 ug/ml in all the patients and 19% (21/108) of them developed antibodies, and 52 patients reached early MH. During 52 weeks' follow-up. Twenty-eight percent (30/108) of patients showed loss of response to IFX. Patients who lost response had lower early S-IFX than those who had sustained response (3.01 ± 3.66 vs. 5.47 ± 6.79 ug/ml, p = .02; 48 vs. 23%, p = .02). At week 52, 73 patients had repeated endoscopy and 42% of them reached MH. Early S-IFX had a predictive value on MH at week 52. When early S-IFX > 2.5 ug/ml, the sensitivity for predicting MH at week 52 was 87%, and the specificity were 61% (AUC = 0.73, p < .01). The combined predictive value of early S-IFX and early MH became stronger. Only 6% (1/18) of those patients who had low early S-IFX and had not reached early MH could reach MH at week 52.
Conclusions: Early S-IFX and early MH could predict one-year response after initiating IFX therapy in Crohn's disease.
Keywords: Crohn’s disease (CD); early mucosal healing (MH); early serum infliximab trough level (S-IFX); infliximab; outcome.