Rate and Predictors of Mucosal Healing in Ulcerative Colitis Treated with Thiopurines: Results of a Multicentric Cohort Study.

Background And Aims: Mucosal healing (MH) with thiopurines has been poorly investigated in ulcerative colitis (UC). We aimed to assess MH rate in UC patients treated with thiopurine monotherapy.

Patients And Methods: We retrospectively collected all UC patients treated with thiopurines more than 6 months who have undergone colonoscopy at baseline and after at least 6 months of treatment. Patients were recruited from January 2005 to May 2015 through a personal database and/or standardized hospital inpatient diagnostic dataset. Patients were excluded in case of any use of other immunomodulator or biological agent. MH was defined as a Mayo endoscopic subscore ≤1 and UCEIS ≤ 2. Histological healing (HH) was defined by the absence of epithelial polynuclear infiltrate, cryptic abscesses, or ulcerations.

Results: Eighty patients (31 women, median age 43 [IQR 32-58]) were included. Median disease duration was 10.5 [6-16] years. At baseline, median full Mayo score, endoscopic subscore, and UCEIS were 8 [6.8-10], 3 [2-3], and 5 [3-6], respectively. MH was first assessed after a mean follow-up of 38 ± 31 months. Median full Mayo score, endoscopic subscore, and UCEIS decreased to 3.5 [1-6], 2 [0-2.2], and 2 [0-4], respectively. MH was achieved in 43.7%, HH in 38%. In multivariate analysis, predictors of MH were thiopurine exposure duration ≥2 years [odds ratio (OR) 2.9, CI 95% (1.1-7.6), p = 0.03] and a prior acute severe colitis [OR 5.9, CI 95% (1.1-32), p = 0.04]. Factors associated with MH during treatment were partial Mayo score ≤2 (NPV = 100%), BMI ≥ 25 kg/m (NPV = 75%), and MCV ≥ 95 fL (NPV = 73%).

Conclusions: In UC, thiopurine monotherapy is associated with MH in 43.7% and HH in 38%.