Overall and cause-specific mortality in ulcerative colitis: meta-analysis of population-based inception cohort studies

OBJECTIVES: It remains debated whether patients with ulcerative colitis (UC) are at greater risk of dying and whether a possible alteration in mortality can be attributed to specific causes of death. We aimed to clarify this issue by conducting a meta-analysis of population-based inception cohort studies on overall and cause-specific mortality in patients with UC. METHODS: The MEDLINE search engine and abstracts from international conferences were searched for relevant literature by use of explicit search criteria. STATA meta-analysis software was used to calculate pooled risk estimates (SMR, standardized mortality ratio, observed/expected deaths) of overall mortality and specific causes of death and to conduct metaregression analyses of the influence of specific variables on SMR. RESULTS: Ten papers fulfilled the inclusion criteria, reporting SMRs varying from 0.7 to 1.4. The overall pooled estimate was 1.1 (95% confidence interval [CI] 0.9-1.2, P= 0.42). However, greater risk of dying was observed during the first years of follow-up, in patients with extensive colitis, and in patients from Scandinavia. Metaregression analysis showed an increase in SMR by increasing cohort size. UC-related mortality accounted for 17% of all deaths. Mortality from gastrointestinal diseases, nonalcoholic liver diseases, pulmonary embolisms, and respiratory diseases was increased whereas mortality from pulmonary cancer was reduced. CONCLUSIONS: The overall risk of dying in patients with UC did not differ from that of the background population, although subgroups of patients were at greater risk of dying. The cause-of-death distribution seemed to differ from that of the background population.