- Background: Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is a leading cause of morbidity and mortality. It is a major risk factor for thromboembolic disease and it is well known that even short episodes of intermittent AF convey an increased risk for stroke. These events can be avoided with anticoagulation treatment for patients in high risk (according to CHA2DS2-VASc score). Objective: Creating a risk score within the general population for identifying individuals at high risk for diagnosis of non-valvular AF. Methods: A retrospective cohort study, based on Clalit Health Services (CHS) data warehouse. The study population consists all adult members older than 40 years, with no previous diagnosis of AF.