Inflammatory bowel disease increases the risk of atrial fibrillation, particularly during active disease stages:a nationwide cohort study

Purpose: Inflammation plays a role in the development of atrial fibrillation (AF). Thus, inflammatory bowel disease (IBD) may increase the risk of AF. We therefore investigated the risk of AF in patients with IBD in a Danish nationwide cohort. Methods: We included all incident patients with IBD from 1996-2011. Each IBD patient was matched by age and sex with ten population controls. An IBD flare was defined as the first 120 days after either hospital admission, prescription(s) of glucocorticoids or initiation of biological treatment. Persistent activity succeeded flares in cases with repeated glucocorticoid prescriptions or hospitalizations within 120 days of onset of a flare, and remissions started after 120 days without IBD activity. Poisson regression analysis was used to estimate the relative risk (RR) of AF controlling for comorbidity and concomitant medications as time-dependent covariates. Results: We identified 24,527 IBD patients with a mean age of 43.9 years and 236,550 matched controls. A total of 685 IBD patients and 4,390 controls were diagnosed with AF corresponding to incidence rates of 4.16 and 2.70 per 1000 person-years. Patients with IBD had an increased risk of AF (Figure) with age- sex- and calendar-year adjusted RR 1.60 (95% confidence interval [CI] 1.47-1.74) and fully adjusted RR 1.17 (1.08-1.27). During flares and periods with persistent activity the RRs of AF increased to 2.36 (2.03-2.75) and 1.68 (1.36-2.08), respectively. In remission periods the risk of AF was similar to controls and lower (p