Atrial fibrillation (AF) is a growing public health problem associated with significant morbidity and mortality. Numerous randomized controlled trials of warfarin have conclusively demonstrated that long-term anticoagulation therapy can reduce the risk for stroke by approximately 68% per year in patients with nonvalvular AF, and even more in patients with valvular AF. However, available data show that of those patients with AF and no contraindication to warfarin therapy, only 15% to 44% are prescribed warfarin. Our literature review has identified patient-, physician-, and health care system-related barriers to warfarin prescription. However, the relative importance of these specific barriers remains unknown. Further work is needed to understand the discrepancy between the randomized controlled trial evidence and clinical practice patterns.

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Collaborative efforts among health care professionals, regulatory health authorities, and patients led to the development of the current prescribing model for pharmacists practicing in Alberta. The model includes provisions for adapting a prescription, prescribing in an emergency, and additional prescribing by pharmacists who obtain authorization.

BackgroundAnticoagulation management services (AMSs) are widely used for anticoagulation management in many countries. Our AMS is a pharmacist-run ambulatory clinic with a physician advisory committee that manages patients referred with complicated anticoagulation histories. This paper assesses the adequacy of anticoagulation, rates of anticoagulant-related events and associated health care resource utilization for patients before and after referral to our AMS.MethodsConsecutive patients referred to the AMS with 4 months of prior anticoagulation management who also had anticoagulation management for 4 months within the AMS were included in the evaluation. The primary endpoint was adequacy of anticoagulation (target international normalized ratio [INR] ± 0.5). Secondary outcomes included adverse events requiring an emergency department (ED) visit or hospital stay. These were classified by International Classification of Diseases (ICD) codes as thromboembolic, hemorrhagic, or non-anticoagulant related. Health care system resource consumption data were collected as number of hours spent in an ED and hospitalization costs.ResultsA total of 125 patients were included: 57.6% were male, with a mean age of 62.9 (standard deviation [SD]) ± 15.0 years. Indications for warfarin therapy were atrial fibrillation (40.0%), mechanical valve replacement (24.0%) and venous thromboembolism (19.2%). The adequacy of anticoagulant control was significantly greater during AMS care compared with the period before referral; patients were in the target INR range 66.5% versus 48.8% of the time, respectively (95% confidence interval [CI] 13.4%–22.0%; p < 0.0001). The relative risk of a thromboembolic event before referral to AMS care was 17.6 (95% CI 6.0–51.9; p < 0.0001), while the relative risk of a hemorrhagic event before AMS care was 1.6 (95% CI 0.7–3.7; p = 0.25). During AMS care, savings included 572 hours in the ED and Cdn$122,145.40 in hospitalization costs.ConclusionsA pharmacist-directed, physician-supported AMS program achieved significantly better INR control and reduced rates of thromboembolic complications compared with standard care. Resource utilization was substantially reduced during AMS care.

Although warfarin was the most appropriate treatment in nearly all of this population at high risk for stroke, it was prescribed in fewer than two-thirds of patients. Antithrombotic therapy was not always prescribed in accordance with patients' risk factors for stroke and bleeding. There is a need for systematic identification of appropriate candidates for anticoagulation in the long-term care setting.