Mortality Risk in Irritable Bowel Syndrome: Results From a Nationwide Prospective Cohort Study

Abstract

Introduction: Mortality concern is a frequent driver of care seeking in patients with irritable bowel syndrome (IBS). Data on mortality in IBS are scarce, and population-based studies have been limited in size. We examined mortality in IBS.

Methods: A nationwide, matched, population-based cohort study was conducted in Sweden. We identified 45,524 patients undergoing a colorectal biopsy at any of Sweden's 28 pathology departments and with a diagnosis of IBS from 2002 to 2016 according to the National Patient Register, a nationwide registry of inpatient and outpatient specialty care. We compared the mortality risk between these individuals with IBS and age- and sex-matched reference individuals (n = 217,316) from the general population and siblings (n = 53,228). In separate analyses, we examined the role of mucosal appearance for mortality in IBS. Finally, we examined mortality in 41,427 patients with IBS not undergoing a colorectal biopsy. Cox regression estimated hazard ratios (HRs) for death.

Results: During follow-up, there were 3,290 deaths in individuals with IBS (9.4/1,000 person-years) compared with 13,255 deaths in reference individuals (7.9/1,000 person-years), resulting in an HR of 1.10 (95% confidence interval [CI] = 1.05-1.14). After adjustment for confounders, IBS was not linked to mortality (HR = 0.96; 95% CI = 0.92-1.00). The risk estimates were neutral when patients with IBS were compared with their siblings. The underlying mucosal appearance on biopsy had only a marginal impact on mortality, and patients with IBS not undergoing a colorectal biopsy were at no increased risk of death (HR = 1.02; 95% CI = 0.99-1.06).

Discussion: IBS does not seem to confer an increased risk of death.

Figure 1:

Flow chart of identified patients and their matched comparators IBS, irritable bowel syndrome; IBD, inflammatory bowel disease; SNOMED, Systematized Nomenclature of Medicine

Figure 2:

Kaplan-Meier survival curves of time to all-cause mortality (follow-up until Dec 31, 2017) and cause-specific mortality (follow-up until Dec 31, 2016) in patients with IBS and matched comparators IBS, irritable bowel syndrome; CVD, cardiovascular disease