The Pattern of Underlying Cause of Death in Patients with Inflammatory Bowel Disease in England: A Record Linkage Study

Background and Aims: Numerous studies have established that mortality risk in inflammatory bowel disease [IBD] patients is higher than in the general population, but the causes of death have seldom been examined. We aimed to describe causes of death in IBD. Methods: A matched cohort study using UK general practice data from Clinical Practice Research Datalink linked to death registration records. We described the distribution of causes of death among IBD patients by age at death and time since IBD diagnosis. We estimated age-specific mortality rates and hazard ratios of death in multivariable Cox proportional hazards models. Results: 20 293 IBD patients were matched to 83 261 non IBD patients. The mortality rate was 40% higher in IBD patients [2005 deaths] than in non IBD patients [6024 deaths] (adjusted overall hazard ratio: = 1.4, 95% confidence interval [CI]: = 1.4-1.5], with greater risk of death in Crohn's disease [hazard ratio: = 1.6, 1.5-1.7] than in ulcerative colitis [1.3, 1.3-1.4]. Causes attributable to IBD constituted 3.7% of all deaths in ulcerative colitis and 8.3% in Crohn's disease. Among IBD patients, death was less likely to be due to circulatory, respiratory or neoplastic diseases than among non IBD patients. In both IBD and non IBD patients all these causes became more clinically important with advancing age, with the commonest neoplastic cause of death being lung cancer rather than gastrointestinal cancers. Conclusions: IBD patients have an additional risk of death. Most IBD patients die of circulatory or respiratory causes, and the contribution to mortality from long-term complications of IBD is clinically less important.