BACKGROUND Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease, associated with a number of cardiovascular diseases. We sought to investigate whether AS increases the risk of atrial fibrillation (AF) in a nationwide population-based study.

METHODS A total of 14,129 patients newly diagnosed with AS (mean age 41.8 ± 15.3 years, 72% male) were recruited from the Korean National Health Insurance Service database between 2010 and 2014 and followed up for new onset AF. Age- and sex-matched non-AS subjects (1:5, n = 70,645) were selected and compared with the AS patients.

RESULTS During a mean follow-up of 3.5 years, AF was newly diagnosed in 486 patients (114 patients of the AS group). The AS patients developed AF more frequently than the non-AS subjects (2.32 vs. 1.51 per 1000 person-years). In multivariate Cox regression analysis, AS was an independent risk factor for AF (Hazard ratio [HR] 1.28, 95% confidence interval [1.03-1.58]). The AS with tumor necrosis factor inhibitor (TNFi) therapy group showed higher risk for AF (HR 1.60 [1.02-2.39]). In younger patients of the AS group (patients <40 years old), the risk for AF was three times higher than patients at same age in the non-AS group. AS was an independent risk factor for AF in men, but not in women (HR 1.53 [1.18-1.95]; HR 1.42 [0.94-2.08], respectively).

CONCLUSIONS AS was an independent risk factor for AF, especially in those under 40 years of age and those administered TNFi. It would be reasonable to screen for AF and stroke prevention in these high-risk patients.