Atrial fibrillation is very common, such that by age 40 years, there is a 1 in 4 lifetime risk of developing atrial fibrillation.1 The prevalence of atrial fibrillation increases substantially with advancing age, from 0.5% at age 40 through 50 years to 5% through 15% at age 80 years. Atrial fibrillation significantly increases the risk of mortality, heart failure, and myocardial infarction, as well as the risk of stroke, which may be severe due to a cardioembolic origin. However, treatment of patients with atrial fibrillation with oral anticoagulation is effective in reducing stroke risk by approximately two-thirds and reducing mortality by almost one-third, with a relatively smaller increased risk of major bleeding, such that the net clinical benefit favors anticoagulation for almost all patients with atrial fibrillation.2 European and US guidelines therefore recommend anticoagulant therapy when stroke risk, as calculated by CHA2DS2-VASc score, is 2 or higher.1,2 Such pronounced treatment effects are rarely seen in therapies for other conditions for which screening is undertaken.
Ben Freedman S, Lowres N. Asymptomatic Atrial FibrillationThe Case for Screening to Prevent Stroke. JAMA. 2015;314(18):1911-1912. doi:10.1001/jama.2015.9846