Effect of access to anticoagulation management services on warfarin use in patients with atrial fibrillation

Abstract

Study objective: To determine the effect of access to ambulatory anticoagulation management services (AMS) on the rate of warfarin use in patients with atrial fibrillation.

Design: Retrospective medical record review.

Setting: Two ambulatory care clinics in the same managed care system: one with and one without access to pharmacist-managed AMS.

Patients: One hundred seventy-eight patients with atrial fibrillation diagnosed between June 2000 and June 2001.

Measurements and main results: Warfarin use was assessed overall and by contraindications and risk factors for stroke. Independent predictors of therapy were identified. The overall rate of warfarin use in atrial fibrillation was higher in the clinic with access to AMS than in the clinic without access (77.9% vs 61.7%, p=0.03). In patients with no known contraindications, warfarin use increased by 20.2% with access to AMS versus no access (80.2% vs 60.0%, p=0.023). Patients aged 65 years or older with one or more risk factors for stroke and no contraindications were more likely to receive warfarin in the clinic with access to AMS than in the clinic without access (85.1% vs 53.8%, p=0.001). Access to AMS was an independent predictor of warfarin use (odds ratio 2.19, 95% confidence interval [CI] 1.05-4.56). Female sex was an independent negative predictor of warfarin use (odds ratio 0.48, 95% CI 0.24-0.96).

Conclusion: In the managed care setting, use of warfarin for stroke prophylaxis in patients with atrial fibrillation was higher in the ambulatory care clinic with access to pharmacist-managed AMS than in the clinic without access.