P631 Effectiveness of Early Thiopurine Use in Korean Patients with Moderate-to-Severe Ulcerative Colitis: A Prospective Multicenter Cohort (MOSAIK) study

Abstract

Abstract Background Thiopurines play an important role in the management of steroid-refractory steroid-dependent ulcerative colitis (UC). However, the effectiveness of the early use of thiopurines in UC remains controversial. Methods In this multicenter prospective cohort study, we divided patients with UC into those who underwent early (within 6 months of diagnosis) and late (6 months after diagnosis) thiopurine therapy to determine the effectiveness of early thiopurine treatment. The primary outcome was the cumulative rate of clinical relapse (Mayo score >2 points). Multivariate Cox proportional hazards regression was used to identify independent clinical factors associated with the outcomes. Results Overall, 333 patients with moderate-to-severe UC were included in the MOSAIK study. Of the 118 patients treated with thiopurines, 65 (55.1%) and 53 (44.9%) received thiopurine therapy within and after 6 months of diagnosis. The cumulative use rate of thiopurines was 38.96% at 3 years after diagnosis. The median initial dose of thiopurines was 0.7 mg/kg (0.3–2.0), and the median maintenance dose was 1.1 mg/kg (0.3–2.4). The cumulative rate of clinical relapse was not significantly different between patients who started thiopurine therapy within 6 months of diagnosis and those who started therapy 6 months after diagnosis during a 3–year period (p = 0.712). Multivariate analysis showed that the presence of extraintestinal manifestations (hazard ratio [HR]: 4.674, 95% CI: 1.210–18.061, p = 0.025) independently predicted an increased risk of clinical relapse. Conclusion Patients with UC who received early thiopurine therapy did not differ significantly in terms of clinical relapse compared with those who received late therapy.