Graves’ disease, its treatments, and the risk of atrial fibrillation: A Korean population-based study

BACKGROUND: Atrial fibrillation (AF) is occasionally diagnosed in individuals with Graves’ disease. Definite treatments, including radioactive iodine therapy (RAIT) or surgery might lower the risk of AF in the literature. However, no studies have compared the effects of anti-thyroid drugs (ATDs), RAIT, and surgery on the risk of AF. METHODS: This retrospective cohort study included 94,060 newly diagnosed Graves’ disease patients and 470,300 controls from the Korean National Health Insurance database. The incidence of AF was evaluated in patients and controls. Patients were categorized based on treatment method into ATD (95.6%), RAIT (3.5%), and surgery (0.9%) groups. In the ATD group, the dose and duration of ATDs were calculated for each patient. In the RAIT and surgery groups, remission was defined as levothyroxine prescription. RESULTS: Graves’ disease patients had a 2.2-fold higher risk of developing AF than controls. Regardless of demographic factors, the patient group had a consistently higher risk of AF than controls, with the highest risk of AF (HR, 5.49) in the younger patient group. The surgery group had a similar risk of AF compared with controls, whereas the ATD (HR, 2.23) and RAIT (HR, 2.00) groups had increased risks of AF, even in patients reaching hypothyroid status after RAIT. Patients with higher dose or longer treatment duration of ATDs were at greater risk of AF. CONCLUSION: We observed differing risks of AF according to methods of treatment for Graves’ disease, and that definite treatment can be an option for subjects needing sustained medical treatment considering the risk of AF.