PURPOSE: Oral anticoagulation therapy with warfarin can significantly reduce stroke risk in patients with atrial fibrillation (AF). However, the beneficial outcomes are directly dependent on the quality of anticoagulation management. Management in the US is provided predominantly in the community setting. The purpose of our study is to define the quality of anticoagulation with warfarin in patients with nonvalvular AF who are managed exclusively in community practices, and to contrast the quality in cardiology and primary care practices.
METHODS: This is a retrospective, observational, multi-center study of 392 patients in the community setting who were initiated on anticoagulation with warfarin therapy to prevent stroke associated with atrial fibrillation. International Normalized Ratio (INR) values were collected over a one-year period and the quality of management was expressed as time in therapeutic range (TTR) calculated by the linear interpolation method.
RESULTS: One hundred patients from cardiology practices and 292 patients from primary care practices were studied. During the one-year period, the overall mean TTR was 56.7%. The TTR in the primary care practices vs cardiology practices was 55.3% vs. 60.8% (p=0.016). Both practices had similar percent of time below therapeutic range, 29.8% vs. 29.2%. However, the primary care practice patients were above the therapeutic range 15% of the time vs. 10% in the cardiology practice (p < 0.001). There was one death secondary to intracranial bleed and one major bleed in the primary care group.
CONCLUSIONS: The quality of anticoagulation with warfarin, as assessed by TTR, in the current community setting remains suboptimal. Compared to historical data, there has been little to no improvement in the quality of INR control in current clinical practices that do not utilize anticoagulation clinics.
CLINICAL IMPLICATIONS: The quality of anticoagulation with warfarin, in the current community setting remains inadequate and indicate the need for improved INR control for prevention of thromboembolism. It is possible that additional patient education, specialty clinics, the wider use of algorithms and newer agents may improve patient outcomes.
DISCLOSURE: Seol Young Han: Other: Study was sponsored by Boehringer-Ingelheim Pharmaceuticals but has not contributed to salary.
Ron Aronson: Employee: Full time employee of Boehringer-Ingelheim Pharmaceuticals
Samuel Broderick: Other: Received research funding from Boehringer-Ingelheim Pharmaceuticals - sponsor of the study
Stephen Sander: Other: Full time employee of Boehringer-Ingelheim Pharmaceuticals
Scott Stevens: Other: Site PI for the NIH-sponsored COAG trial, co-investigator on the COUMAGEN I and COUMAGEN II trials (all relevant to warfarin pharmacogenetics), and site PI or Co-I for trials using apixaban and rivaroxaban. None of the above have contributed to salary.
Eric Valezquez: Other: Received research funding from Boehringer-Ingelheim Pharmaceuticals - sponsor of the study
Galen Wagner: Other: Received research funding from Boehringer-Ingelheim Pharmaceuticals - sponsor of the study
John Heitner: Other: Study was sponsored by Boehringer-Ingelheim Pharmaceuticals
The following authors have nothing to disclose: Sebastian Palmeri, Vic Hasselblad, David Rendall, Alan Tenaglia, David Whellan
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