Systemic lupus erythematosus is a risk factor for atrial fibrillation: a nationwide, population-based study

Objective Cardiac involvement is present in more than half of the patients with systemic lupus erythematosus (SLE). However, large-scale studies on the prevalence of atrial fibrillation (AF) in this disease do not exist. We aimed to investigate the incidence and clinical significance of AF in SLE. Methods Patients with SLE (n=21,143; mean age, 41.8 +/- 13.13 years; female, 90.38%) without previous AF were selected from the Korean National Health Insurance Service National Sample Cohort database between 2008 and 2014. Age-and sex-matched controls (n=105,715) were randomly sampled in a 5:1 ratio from the population of individuals without SLE from the same database. Both cohorts were followed-up for incidental AF and death until 2015. Results AF was newly detected in 481 (2.27%) patients with SLE and 619 (0.59%) controls (incidence: 3.692 and 0.941 per 1000 person-years, respectively). After multivariate adjustment, SLE was found to be a risk factor for developing AF [hazard ratio (HR), 2.84; 95% confidence interval (CI), 2.50-3.23]. On subgroup analysis, younger (age <40) patients showed a higher incidence of AF. SLE patients with incidental AF had a higher mortality rate compared with patients without SLE with AF (HR, 2.35; 95% CI 1.73-3.20) and those with SLE without AF (HR, 3.53; 95% CI 2.84-4.39) after adjustment. Conclusion SLE was an independent risk factor for AF development, especially in younger patients without previous AF, stressing the importance of cardiac assessment in this population. Development of AF in patients with SLE was associated with increased mortality.