Increased atrial fibrillation risk in rheumatoid arthritis: Greater in seropositive than seronegative patients

Background The link between rheumatoid arthritis (RA) and atrial fibrillation (AF) has received less attention. Objective This study aimed to examine the association between RA and incident AF in a nationwide cohort, with particular focus on differences according to serostatus - seropositive RA (SPRA) and seronegative RA (SNRA). We explored the potential influence of biologic or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) use as a secondary objective. Methods This retrospective cohort study used the National Health Insurance Service database to include participants who were first diagnosed with RA between 2010 and 2017. Matched non-RA controls were selected by age and sex (1:3 ratio). Participants were followed from 1 year after the index date (to mitigate surveillance bias) until December 31, 2020. Results A total of 48,885 patients with RA (34,699 SPRA, 14,186 SNRA) and 146,655 matched controls were included. Patients with RA had a significantly higher risk of AF than non-RA controls (adjusted hazard ratio [aHR] 1.55, 95% confidence interval 1.46-1.65). Both patients with SPRA and SNRA had a higher AF risk than non-RA controls (aHR 1.63 in SPRA, 1.37 in SNRA). Patients with SPRA had a higher risk compared with those with SNRA (aHR 1.19, 95% confidence interval 1.02-6.34). The use of biologic disease-modifying antirheumatic drugs was associated with a slightly higher risk of AF, while targeted synthetic disease-modifying antirheumatic drug use led to risk reduction, but was not statistically significant. Conclusion This study shows that both patients with SPRA and SNRA are at a significantly greater risk for AF compared with non-RA controls, with patients with SPRA at the highest risk.