Stournaras E, Qian W, Pappas A, et al. - In ulcerative colitis (UC) and Crohn disease (CD), researchers evaluated the long-term effectiveness of thiopurines, including their impact on the need for surgery, the largest series reported to date. Outcomes were evaluated in 11,928 individuals (4,968 with UC, 6,960 with CD) from the UK IBD BioResource who were initiated on thiopurine monotherapy with the intention of maintaining medically induced remission. Thiopurine monotherapy appeared effective for the duration of treatment in 2,617/4,968 (52.7%) patients with UC vs 2,378/6,960 (34.2%) patients with CD, after assessing 68,132 patient-years of exposure. Overall, the authors concluded that thiopurine monotherapy is an effective long-term treatment for UC, but significantly less so for CD. Thiopurine intolerance was linked with a greater risk of surgery in UC, with a more modest impact on need for surgery in CD.