Thromboembolic prophylaxis in nonrheumatic atrial fibrillation: utilization patterns, efficacy, and complications in a long-term follow-up of community patients

OBJECTIVES: To define the incidence, contemporary utilization patterns, efficacy, and complications of thromboembolic prophylactic treatment in patients with chronic (CAF) and paroxysmal atrial fibrillation (PAF). BACKGROUND: Although recent randomized trials with antithrombotic therapy in nonrheumatic atrial fibrillation (AF) patients emphasized the benefits of warfarin in preventing stroke, warfarin treatment is still far from optimal. METHODS: A retrospective analysis of the medical records of 506 patients with nonrheumatic PAF or CAF from 23 clinics in the north of Israel, including an interview with the patients' family physician. RESULTS: (1) The most effective treatment for preventing thromboembolic events (a reduction of 75.9%) was warfarin at an international normalized ratio (INR) intensity of 2-3. (2) After diagnosis, 26.9% of the patients were treated with warfarin. (3) During the follow-up period (not following a thromboembolic event), an additional 26.9% of the patients began treatment with warfarin. (4) Elderly patients (p<0.001), patients with limited activity of daily living (ADL) (p<0.012) or instrumental activity of daily living (IADL) (p<0.001), and patients with PAF (p<0.0001) were less likely to be treated with warfarin. (5) Three new risk factors found for thromboembolic event were limited ADL (p<0.001), limited IADL (p<0.002), and extended duration of AF (p<0.006). CONCLUSIONS: Less than optimal utilization patterns of thromboembolic prophylactic treatment with anticoagulants were found, especially regarding elderly patients, patients with limited ADL and IADL, and patients with PAF, despite the fact that their thromboembolic risk is as high or higher than that of other patients with AF.