Early management of acute severe UC in the biologics era: development and international validation of a prognostic clinical index to predict steroid response by Adams, A, Gupta, V, Mohsen, W, Chapman, TP, Subhaharan, D, Kakkadasam Ramaswamy, P, Kumar, S, Kedia, S, McGregor, CG, Ambrose, T, George, BD, Palmer, R, Brain, O, Walsh, A, Ahuja, V, Travis, S, Satsangi, J