Prognosis and Guideline-Adherent Antithrombotic Treatment in Patients With Atrial Fibrillation and Atrial Flutter: Implications of Undertreatment and Overtreatment in Real-life Clinical Practice; the Loire Valley Atrial Fibrillation Project

Background In patients with atrial fibrillation (AF), adherence to guidelines for antithrombotic treatment is poorly followed, and undertreatment (or nonadherence with guidelines) is associated with a worse prognosis. The study objective was to evaluate whether this was also the case in a large contemporary series of unselected patients with AF in real-world clinical practice. Methods All patients with AF or atrial flutter seen in our institution between 2000 and 2007 were identified in a database and followed up for mortality and stroke. Antithrombotic guideline adherence was assessed according to the 2006 American College of Cardiology/American Heart Association/European Society of Cardiology guidelines. Results We reviewed outcomes in 3,646 consecutive patients with AF or atrial flutter (aged 71 ± 14 years; mean CHADS 2 [congestive heart failure, hypertension, aged ≥ 75 years, diabetes mellitus, prior stroke or transient ischemic attack] score, 1.5 ± 1.1). Antithrombotic treatment was in agreement with the guidelines in 53% of patients, whereas 31% were classified as undertreated and 16% as overtreated. Among other parameters, nonpermanent AF and atrial flutter were independently associated with an increased risk of undertreatment. After a follow-up of 953 ± 767 days (median, 771 days; interquartile range, 1,286 days), guideline adherence was associated with a lower risk of adverse events (death from all causes or stroke) compared with undertreatment (relative risk, 0.47; 95% CI, 0.40-0.55; P P Conclusions Guideline nonadherence and undertreatment with antithrombotic agents in unselected real-world patients with AF or atrial flutter are independently associated with a high risk of stroke and mortality.