Increased risks of aortic regurgitation and atrial fibrillation in radiographic axial spondyloarthritis patients: a 10-year nationwide cohort study

Background: To compare the incidences of aortic regurgitation, atrial fibrillation (AF), and atrioventricular (AV) block II–III between radiographic axial spondyloarthritis (r-axSpA) patients and the general population (GP). Methods: National Health Insurance Services data were used. R-axSpA patients (N = 8877) and the age- and sex-matched GP (N = 26,631) were followed from August 2006 to December 2019. Incidence rates and standardized incidence ratios (SIRs) of aortic regurgitation, AF, and AV block II–III were compared between these groups. Ten-year incidence rates and hazard ratios (HRs) were calculated by the Kaplan–Meier method and Cox regression analysis. Results: Incidence rates of aortic regurgitation, AV block II–III, and AF in the r-axSpA group were 0.42, 0.21, and 4.0 per 1000 person-years (PYs), respectively. In the r-axSpA group, the SIR for aortic regurgitation was highest among 40- to 49-year-old men (4.11). Incidence rates of aortic regurgitation and AF were higher in the r-axSpA group than in the GP group (0.42 versus 0.18 per 1000 PYs 4.00 versus 3.13 per 1000 PYs, both p < 0.001, respectively), whereas the difference was insignificant for AV block II–III (0.21 versus 0.14 per 1000 PYs, p = 0.222). In multivariate analysis, r-axSpA was associated with a higher hazard (risk) for the development of aortic regurgitation and AF [HR (95% confidence interval) = 2.55 (1.49–4.37) and 1.20 (1.04–1.39), respectively], but the difference was insignificant for AV block II–III [HR (95% confidence interval) = 1.17 (0.59–2.31)]. Conclusions: Compared with the GP, r-axSpA patients are at increased risk of aortic regurgitation and AF, but not AV block II–III. These patients should be carefully monitored for occurrence of aortic regurgitation and AF.