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.
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.
We reviewed outcomes in 3,646 consecutive patients with AF or atrial flutter (aged 71 ± 14 years; mean CHADS2 [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 < .0001). Overtreatment was associated with a lower risk of adverse events compared with the guideline-adherent population (relative risk, 0.40; 95% CI, 0.28-0.58; P < .0001). Factors independently associated with increased risk of mortality or stroke were antithrombotic undertreatment, older age, heart failure, renal failure, diabetes, male sex, and previous history of stroke.
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.