Mortality in inflammatory bowel disease: a population-based cohort study

BACKGROUND & AIMS: There is no consensus regarding any increase in mortality 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.