Hyperthyroidism and Risk of Atrial Fibrillation or Flutter

Methods: We identified all patients with an incident hospital diagnosis of hyperthyroidism during the study period in the Danish National Registry of Patients, and among those we identified patients with a diagnosis of atrial fibrillation or flutter that occurred ±30 days from the date of the hospital diagnosis of hyperthyroidism. We used logistic regression analysis to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between sex, 10-year age group, cardiovascular diseases, and risk of atrial fibrillation or flutter. Results: Among 40628 patients diagnosed as having hyperthyroidism,3362(8.3%)werediagnosedashavingatrial fibrillation or flutter within ±30 days from the date of the diagnosis of hyperthyroidism. The following factors were associatedwithriskofatrialfibrillationorflutter:malesex (OR, 1.8; 95% CI, 1.6-1.9), age (OR, 1.7; 95% CI, 1.7-1.8) per10-yearincrement,ischemicheartdisease(OR,1.8;95% CI,1.6-2.0),congestiveheartfailure(OR,3.9;95%CI,3.54.4), and heart valve disease (OR, 2.6; 95% CI, 1.9-3.4). Conclusion:Malesex,increasingage,ischemicheartdisease, congestive heart failure, and heart valve disease are associated with an increased risk of atrial fibrillation or flutter in patients with hyperthyroidism. Arch Intern Med. 2004;164:1675-1678