Mortality in Inflammatory Bowel Disease: A Population-Based Cohort Study

Background & Aims: There is no consensus regarding any increase in mortalityh: with inflammatory bowel disease (IBD). In general, previous studies were not contemporary and were unable to correct for likely confounders. We have performed a large cohort study to examine contemporary IBD related mortality in the United Kingdom. Methods: We selected subjects within the General Practice Research Database with a coded diagnosis of inflammatory bowel disease and up to 5 matched controls for each. We derived the date of recorded deaths and information on smoking and a variety of medical conditions. We calculated both the absolute risk of death and the relative risk as a hazard ratio corrected for available confounders by Cox regression. Results: We included 16,550 IBD cases with 1047 deaths and 82,917 controls with 3758 deaths. The mortality rate was 17.1 per 1000 person-years overall for IBD cases and 12.3 for controls; this difference was greatest in the elderly. Conversion of these figures to hazard ratios by Cox regression gave hazard ratios of 1.54 (1.44-1.65) for all IBD, 1.44 (1.31-1.58) for ulcerative colitis (UC), and 1.73 (1.54-1.96) for Crohn's disease. The greatest hazard ratio for UC was among the 40-59-year age group (1.79 [1.42-2.27]) and for Crohn's disease among 20-39-year-olds (3.82 [2.17-6.75]). Conclusions: IBD is associated with an overall small increase in mortality rate greatest in relative terms in younger subjects but in absolute terms in the elderly.