Abstract 14870: Quality of Anticoagulation Management in Atrial Fibrillation and Venous Thromboembolism: The CVRN WAVE Study
Background: Warfarin is the most commonly prescribed anticoagulant for preventing thromboembolism in patients with atrial fibrillation (AF) and venous thromboembolism (VTE). However, relatively little is known about recent quality of care in patients starting warfarin. We assessed time to reaching target anticoagulation intensity and longitudinal anticoagulation quality after starting warfarin for AF or VTE.
Methods: We conducted a multicenter cohort study of adults with AF or VTE initiating warfarin between 2004-2007 within 5 health plans in the Cardiovascular Research Network (CVRN). We used health plan databases to ascertain information on demographic features, diagnoses, procedures, drug exposure, and lab results. Longitudinal warfarin exposure was based on dispensed prescriptions and outpatient international normalized ratio (INR) tests using a validated algorithm. Time to reaching target INR was defined as the number of days needed to achieve two consecutive INR 2-3 between days 8 and 90 after starting warfarin. Anticoagulation quality was measured using percentage of time in therapeutic INR range (%TTR) 2-3.
Results: Among 34,331 adults initiating warfarin, 25,570 had AF and 9649 had VTE. Mean (SD) age was 70 (13) yr and 46% were women. During the first 90 days after starting warfarin, 79.2% of subjects reached a consecutive target INR (median 31 days), with a lower proportion for AF (77.2%) vs. VTE (85.0%, P<0.001). Overall %TTR was 68.0% and was similar for AF (68.4%) and VTE (65.7%). Multivariable predictors of suboptimal %TTR <60% included a history of cancer, coronary artery bypass surgery, other systemic thromboembolism, intracranial hemorrhage, gastrointestinal bleeding, dementia, lung disease, liver disease, diabetes mellitus or mechanical fall.
Conclusions: In a large, geographically diverse cohort of patients initiating warfarin therapy for AF or VTE, nearly 80% reached consecutive target INR within 90 days. Longitudinal %TTR was similar to that seen in recent clinical trials. Targeting selected patient characteristics associated with suboptimal anticoagulation management may assist in identifying patients that may benefit from more careful monitoring of warfarin therapy or alternative anticoagulation strategies.
- © 2010 by American Heart Association, Inc.