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

Abstract

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. 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. 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. 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.