Use of the CHADS2 risk score to guide antithrombotic treatment in patients with atrial fibrillation - room for improvement

BACKGROUND: Antithrombotic treatment (AT) is recommended for patients with atrial fibrillation (AF), except for those with lone AF or contraindications. AIM: The aim of our study was to determine contemporary AT in AF patients and to ascertain reasons for withholding oral anticoagulant treatment (OAC) in eligible patients. DESIGN: Prospective observational study. METHODS: Consecutive patients were screened for non-valvular paroxysmal or permanent AF. Subjects with newly diagnosed AF or with an indication for AT other than AF were excluded. According to the CHADS2 risk score patients were divided into a low- (CHADS2 = 0), an intermediate (CHADS2 = 1) and a high risk group (CHADS2 > or =2). AT on hospital admission was correlated to current guidelines. RESULTS: 389 patients were screened and 84 (22%) excluded (71 new onset AF, 13 other indications for OAC). Of the remaining 305 patients (80 +/- 10 yrs) 43% had paroxysmal and 57% permanent AF. Eleven patients (4%) were classified as low risk, 61 (20%) as intermediate risk, and 233 (76%) as high risk. In patients at low risk OAC was prescribed in 63%, whereas one third of those at high risk were not on anticoagulant therapy. The main reasons why OAC was withheld in high risk patients were presumed risk of fall in 21 patients (27%), while the grounds were a history of major bleeding and presumed drug non-compliance in 13 (17%), respectively. CONCLUSION: In this survey of AF-patients, AT was not tailored to the thromboembolic risk.