Comparison of accelerated and standard infliximab induction regimens in acute severe ulcerative colitis using propensity score analysis: a retrospective multicenter study in China

Background: The optimal regimen of infliximab salvage in acute severe ulcerative colitis (ASUC) patients remains controversial. This study aimed to compare accelerated and standard infliximab induction in Chinese ASUC patients, and to explore risk factors and concrete accelerated regimens for them. Methods: Data were retrospectively collected from steroid-refractory ASUC patients receiving infliximab as rescue therapy at seven tertiary centers across China. Outcomes including colectomy and clinical remission (Mayo score <= 2 and every subscore <= 1 at Day 14) rates were compared between patients receiving accelerated and standard infliximab induction using propensity score adjustment for potential confounders. The dose-response relationship was explored by plotting restricted cubic splines. Logistic regression and Cox proportional hazards regression analyses were performed to determine risk factors for adverse outcomes. A systematic review and meta-analysis was also performed. Results: A total of 76 patients were analysed: 29 received standard and 47 received accelerated induction. The accelerated group had a higher 90-day colectomy rate (17.8% vs 0%, P = 0.019) and lower clinical remission rate (27.7% vs 65.5%, P = 0.001). After adjusting for propensity score and institution, there was no significant difference in colectomy or clinical remission rates (both P > 0.05). Dose-effect curves showed decreased colectomy hazard with higher cumulative infliximab dosage within 5 days, with no improvement observed for increasing cumulative infliximab dosage within 28 days. Multivariate logistic regression analyses revealed C-reactive protein of >10 mg/L at infliximab initiation (odds ratio = 5.00, 95% confidence interval: 1.27-24.34) as an independent risk factor for no clinical remission. Meta-analysis also revealed no significant difference in colectomy rates at 3 months (P = 0.54). Conclusions: After adjusting for confounders, there were no significant differences in colectomy or clinical remission rates between accelerated and standard infliximab induction among ASUC patients. Early administration of an intensified dosage within 5 days may be beneficial. Elevated C-reactive protein at infliximab initiation indicated need for intensive treatment.