Dong C, et al. - Since acute severe ulcerative colitis (ASUC) is a life-threatening condition, researchers evaluated 3-month and 12-month mortalities in ASUC in population-based studies and in referral centre studies, separately and combined, as well as identified risk factors of mortality in ASUC. This systematic literature review and meta-analysis involved six population-based studies with 741,743 individuals and 47 referral centre-based studies with 2,556 individuals. Findings revealed that the pooled 3-month and 12-month mortalities were 0.84% and 1.01%, respectively. Advanced age was significantly linked to both 3 months and 12 months mortalities. The data presented in this work showed a higher mortality rate in older ASUC patients. Care for elderly patients with severe UC should be improved.