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 2 (NPV = 75%), and MCV ≥ 95 fL (NPV = 73%). Conclusions In UC, thiopurine monotherapy is associated with MH in 43.7% and HH in 38%.