Prevalence of atrial fibrillation in patients with high CHADS2- and CHA2DS2VASc-scores: anticoagulate or monitor high-risk patients?

Background: In patients with known atrial fibrillation (AF) different scores are utilized to estimate the risk of thromboembolic events and guide oral anticoagulation. Diagnosis of AF strongly depends on the duration of electrocardiogram monitoring. The aim of this study was to use established scores to predict the prevalence of AF. Methods: The CHADS(2) -(Congestive Heart failure, hypertension, Age >75 years, Diabetes, Stroke [doubled]) and CHA(2)DS(2)VASc-score (Congestive Heart failure, hypertension, Age >= 75 years [doubled], Diabetes, Stroke [doubled], Vascular disease, Age 65-74 years, Sex category [female sex]) was calculated in 150,408 consecutive patients, referred to the University Hospital of Rostock between 2007 and 2012. All factors constituting these scores and a history of AF were prospectively documented with the ICD-10 admission codes. Results: Mean age of our study population was 67.6 +/- 13.6 years with a mean CHADS(2)-score of 1.65 +/- 0.92 and CHA(2)DS(2)VASc-score of 3.04 +/- 1.42. AF was prevalent in 15.9% of the participants. The prevalence of AF increased significantly with every CHADS(2)- and CHA(2)DS(2)VASc-score point up to 54.2% in CHADS(2)-score of 6 and 71.4% in CHA(2)DS(2)VASc-score of 9 (P < 0.001). Conclusion: The prevalence of AF increases with increasing CHADS(2)- and CHA(2)DS(2)VASc-score. In intermediate scores intensified monitoring may be recommended. In high scores, thromboembolic complications occurred irrespective of the presence of AF and anticoagulant therapy may be initiated irrespective of documented AF.