Abstract
BACKGROUND: Prior research suggests an important role of systemic inflammation in pathogenesis of atrial fibrillation (AF). It is well known that rheumatoid arthritis (RA), a chronic, systemic inflammatory disorder, increases the risk of cardiovascular disease (CVD), but little evidence exists whether the risk of AF is increased in RA. METHODS: Using data from a large US commercial insurance plan, we examined the incidence rate (IR) of hospitalisation for AF in patients with RA compared with non-RA. RA patients were identified with ≥2 separate visits coded for RA and ≥1 disease-modifying antirheumatic drug dispensing. The IR of AF in RA patients was also compared with those with osteoarthritis, a chronic non-inflammatory condition. RESULTS: There were 20 852 RA and 104 260 non-RA patients, matched on age, sex and index date. The mean follow-up was 2 years. The IR per 1000 person-years of AF was 4.0 (95% CI 3.4 to 4.7) in RA and 2.8 (95% CI 2.6 to 3.0) in non-RA patients. The IR ratio for AF was 1.4 (95% CI 1.2 to 1.7) in RA compared with non-RA patients. In a multivariable Cox model adjusting for a number of risk factors such as diabetes, CVD, medications and healthcare utilisation, the risk of AF was no longer increased in RA (HR 1.1, 95% CI 0.9 to 1.4) compared with non-RA patients. There was also no difference in the AF risk between RA and osteoarthritis patients. CONCLUSIONS: Our results show no increased risk of AF associated with RA, after adjusting for various comorbidities, medications and healthcare use.