Population-based evaluation of the management of antithrombotic therapy for atrial fibrillation.

BACKGROUND: Oral anticoagulation is an effective therapy for the prevention of cardioembolic complications in patients with atrial fibrillation. However, previous practice reviews have indicated that oral anticoagulants are often underused in this setting. Most of those reports have focused on reviews of hospitalized and institutionalized patients, or small geographical areas.

OBJECTIVES: To determine the use of antithrombotic therapy for the treatment of atrial fibrillation in Nova Scotia and to survey the knowledge of antithrombotic therapy for atrial fibrillation among a concurrent cohort of primary care and specialist physicians involved in the management of patients with atrial fibrillation.

PATIENTS AND METHODS: Patients with atrial fibrillation were identified through outpatient electrocardiography clinics held throughout Nova Scotia. Following consent of the primary care physicians, patients were contacted and completed a survey about their current management. Family physicians and specialists in Nova Scotia were also surveyed about the management of atrial fibrillation with antithrombotic therapy through the receipt of one of four case scenarios.

RESULTS: Four hundred twenty-five patients participated in the cross-sectional survey. The mean patient age was 70.6 years, 255 (60%) were male and 398 (93.6%) had at least one risk factor for stroke in addition to atrial fibrillation. Two hundred ninety-four patients (69.2%) were receiving oral anticoagulants either alone (61.9%) or in combination with acetylsalicylic acid (ASA) (7.3%). An additional 85 patients (20%) received ASA alone. There was no difference in the rates of prescription of oral anticoagulants between elderly patients (75 years of age and older) and those younger than 75 years (71.7% versus 67.3%, 95% CI -13.1% to 4.5%; P=0.34). Overall, 72.0% of patients were receiving antithrombotic therapy in accordance with the 2001 guidelines of the American College of Chest Physicians, with no difference in the rates between individuals younger than 75 years (72.2%) and those over 75 years of age (71.7%) (absolute difference -0.5%, 95% CI -9.2% to 8.1%). Physician responses to case scenarios indicated that knowledge was high among both general practitioners and specialists regarding the appropriate use of oral anticoagulants for the prevention of thrombotic complications associated with atrial fibrillation.

CONCLUSIONS: The appropriate use of oral antithrombotic therapy for the prevention of thrombotic complications of atrial fibrillation occurs in approximately 72% of patients studied in Nova Scotia, and physician knowledge about this indication is high. There was no bias against prescribing oral anticoagulants to elderly patients. The findings suggest that with time, education and evidence have positively impacted the use of antithrombotic therapy in these patients.