This study assesses 2 different disease activity measures, the Modified Truelove Witts Severity Index and the partial Mayo score, in hospitalized patients with acute severe ulcerative colitis (UC) for prediction of postdischarge corticosteroid-free clinical remission and endoscopic improvement to help guide future considerations for disease activity assessment. In this post hoc analysis from the Tofacitinib for Hospitalized Acute Severe Ulcerative Colitis Management (TRIUMPH) trial, these results suggest resolution of the Mayo rectal bleeding subscore may have high prognostic utility and could be considered as a primary end point for hospitalized UC trials. The study underscores the need for further research on patient-reported outcomes and endoscopic indices in larger populations for inpatient UC trials.