Clinical research studyAre Atrial Fibrillation Patients Receiving Warfarin in Accordance with Stroke Risk?
Section snippets
Study Design
This retrospective cohort study included adult patients in the US MarketScan Commercial Claims and Encounters Database and Medicare Supplemental Database from Thomson Reuters (New York, NY). These databases are derived from employer- and government-funded (Medicare) health care insurance plans and represent 21.6 million individuals covered under a variety of fee-for-service and capitated provider reimbursement schemes. Data from the MarketScan database have been used previously for a range of
Statistical Analysis
All analyses were conducted using SAS version 9 (SAS Institute Inc., Cary, NC). Continuous variables were summarized as mean ± SD and median, while binary data were summarized with percentages. The Charlson Comorbidity Index was calculated according to the method of Romano et al.30 The CHADS2 score was calculated as the sum of points allocated to each of the following stroke risk factors: congestive heart failure exacerbation (1 point), hypertension (1 point), age >75 years (1 point), diabetes
Characteristics of Overall Study Population
Of 573,519 patients in the MarketScan database with a diagnosis of atrial fibrillation/atrial flutter during the study period, 171,393 patients were included in the analysis: 51,907 (30.3%) with newly diagnosed atrial fibrillation/atrial flutter and 119,486 (69.7%) with pre-existing atrial fibrillation/atrial flutter (Figure 1). The mean (SD) duration of continuous eligibility across all patient groups was 41.0 (13.7) months. Overall, patients were of mean age 73.5 years, and 54.8% were male (
Discussion
This study demonstrated that less than half of patients with newly diagnosed or pre-existing atrial fibrillation/atrial flutter in a large US medical claims database received warfarin therapy following a diagnosis of atrial fibrillation/atrial flutter, and only a third of patients starting treatment had 6 months of uninterrupted therapy. Furthermore, the low utilization of warfarin was consistently observed across patients with high, moderate, or low stroke risk.
Despite guideline
Conclusion
This study indicates that physicians currently fail to take sufficient account of patients' overall risk of stroke when considering anticoagulant therapy, and that anticoagulation is generally underused in atrial fibrillation patients. There is a need for continued research in this area to help physicians to balance the risks and benefits of anticoagulation in atrial fibrillation patients, especially in relation to stroke risk. However, until further evidence is available, physicians should
References (35)
- et al.
Assessing the direct costs of treating nonvalvular atrial fibrillation in the United States
Value Health
(2006) - et al.
Risk of stroke in patients with atrial flutter
Am J Cardiol
(2001) Does atrial fibrillation confer a hypercoagulable state?
Lancet
(1995)- et al.
Randomized trial of rate-control versus rhythm-control in persistent atrial fibrillation: the Strategies of Treatment of Atrial Fibrillation (STAF) study
J Am Coll Cardiol
(2003) - et al.
Antithrombotic therapy in atrial fibrillation: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)
Chest
(2008) - et al.
Differential use of warfarin for secondary stroke prevention in patients with various types of atrial fibrillation
Am J Cardiol
(2009) - et al.
Hospitalized patients with atrial fibrillation and a high risk of stroke are not being provided with adequate anticoagulation
J Am Coll Cardiol
(2005) - et al.
Adapting a clinical comorbidity index for use with ICD-9-CM administrative data: differing perspectives
J Clin Epidemiol
(1993) - et al.
Factors affecting bleeding risk during anticoagulant therapy in patients with atrial fibrillation: observations from the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study
Am Heart J
(2005) - et al.
Incidence of stroke in paroxysmal versus sustained atrial fibrillation in patients taking oral anticoagulation or combined antiplatelet therapy: an ACTIVE W Substudy
J Am Coll Cardiol
(2007)
Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the AnTicoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study
JAMA
Impact of atrial fibrillation on the risk of death: the Framingham Heart Study
Circulation
Impact of atrial fibrillation on mortality, stroke, and medical costs
Arch Intern Med
Atrial fibrillation as an independent risk factor for stroke: the Framingham Study
Stroke
Atrial fibrillation is associated with severe acute ischemic stroke
Neuroepidemiology
Is the hypercoagulable state in atrial fibrillation mediated by vascular endothelial growth factor?
Stroke
Risk factors for stroke and efficacy of antithrombotic therapy in atrial fibrillationAnalysis of pooled data from five randomized controlled trials
Arch Intern Med
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Funding: Financial support for the preparation of this manuscript was provided by sanofi-aventis US, Inc. This funding was used for provision of editorial support by Elizabeth Harvey, PhD and Andrew Fitton, PhD of UBC Scientific Solutions.
Conflict of Interest: Dr. Peter Zimetbaum is a research consultant to sanofi-aventis. Dr. Jay Lin is an employee of sanofi-aventis. Hsing-Ting Yu and Matthew Emons are employees of Cerner LifeSciences, which provided consulting services to sanofi-aventis. Yan Xiong and Prajesh Kothawala were employed by Cerner LifeSciences at the time the research was conducted.
Authorship: All authors had access to the study data, and participated in analysis or interpretation of the data (or both), and preparation of the manuscript.