Partial responders to intravenous corticosteroids at day 3 benefit from continued therapy in acute severe ulcerative colitis

In acute severe ulcerative colitis (ASUC), early response patterns to intravenous corticosteroids (IVCS) during the first week may shape subsequent disease course. Characterizing these trajectories is crucial for guiding timely therapy and improving patient outcomes. We evaluated response patterns to IVCS in hospitalized patients with ASUC. Clinical response was categorized as complete response (CR), partial response (PR), or non-response (NR) on days 3, 5, and 7. Patients were followed up to day 90 for need for rescue therapy (RT), post-discharge escalation of therapy (EOT), and mortality. Seventy-nine patients were analyzed. By day 3, 12 (15%) achieved CR, 34 (43%) PR, and 33 (42%) NR. Among the 67 patients with PR or NR on day 3, 9 (13.4%) achieved CR by day 5 and 22 (32.8%) more by day 7. On day 7, CR, PR, and NR were observed in 42 (53%), 17 (21%), and 20 (25%) patients, respectively. Patients with CR on day 3 had a lower, but not statistically significant, likelihood of needing RT + EOT by day 90 compared to NR (29% vs. 47%; p = 0.15). However, by day 5, patients with CR or PR had significantly lower day 90 RT + EOT needs compared to NR (26% vs. 54%, p = 0.02; 23% vs. 54%, p = 0.03). By day 7, the day 90 probability of RT + EOT was higher in PR (45%) and NR (63%) versus CR (16%) (p = 0.001 and < 0.0001, respectively). Only a small proportion of patients with ASUC show CR at day 3; most are partial responders. Partial responders to IVCS at day 3 frequently achieve CR by day 5-7, and have relatively favorable short term disease course, highlighting the prognostic value of early response stratification.