This Article Full Text Full Text (PDF) All Versions of this Article: 37/8/1969    most recent 01.STR.0000230607.07928.17v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lakshminarayan, K. Articles by Herzog, C. A. Search for Related Content PubMed PubMed Citation Articles by Lakshminarayan, K. Articles by Herzog, C. A. Related Collections Anticoagulants Other Stroke Treatment - Medical

(Stroke. 2006;37:1969.)
© 2006 American Heart Association, Inc.

Original Contributions

Atrial Fibrillation and Stroke in the General Medicare Population

A 10-Year Perspective (1992 to 2002)

Kamakshi Lakshminarayan, MD, PhD; Craig A. Solid, MS; Allan J. Collins, MD, FACP; David C. Anderson, MD Charles A. Herzog, MD

From the Departments of Neurology (K.L., D.C.A.) and Medicine (A.J.C., C.A.H.), Hennepin County Medical Center, University of Minnesota, Minneapolis, Minn (K.L., D.C.A.); and the Chronic Disease Research Group, Minneapolis Medical Research Foundation, Minneapolis, Minn (C.A.S., A.J.C., C.A.H.).

Correspondence to Charles A. Herzog, MD, Chronic Disease Research Group, Minneapolis Medical Research Foundation, 914 South 8th Street, Suite S-206, Minneapolis, MN 55404. E-mail cherzog{at}cdrg.org

Background and Purpose— Clinical trials have illustrated warfarin’s protective effect on stroke risk in patients with atrial fibrillation (AF). The current study investigated temporal trends in AF prevalence, warfarin use, and its relation to stroke risk in Medicare patients with AF from 1992 to 2002.

Methods— The Medicare 5% sample for 1992 to 2002 was used to create 1-year cohorts of patients with Medicare as primary payer throughout the year. International Classification of Diseases, Ninth Revision, Clinical Modification codes were used to identify AF, ischemic and hemorrhagic stroke, and comorbid conditions. A previously validated surrogate measure, prothrombin/international normalized ratio claims, was used to identify warfarin use. Cox proportional hazards regression was used to examine time to stroke with warfarin use as a time-dependent variable.

Results— Among Medicare patients aged 65 years, AF prevalence increased from 3.2% in 1992 to 6.0% in 2002 with higher prevalence in older subsets of the study population. Among patients with AF, warfarin use increased significantly (P0.001) for each year examined, from 24.5% in 1992 to 56.3% in 2002. Stroke rates per 1000 patient-years declined from 46.7 in 1992 to 19.5 in 2002 for ischemic stroke but remained fairly steady for hemorrhagic stroke (range, 1.6 to 2.9). Time-to-event modeling confirmed a protective association of warfarin against ischemic stroke among Medicare patients with AF.

Conclusions— This analysis represents an observational validation of stroke prevention in AF trials. The significant increase in warfarin use among patients with AF illustrates diffusion of trial evidence into clinical practice.

Key Words: atrial fibrillation • Medicare • warfarin

This article has been cited by other articles:

				N. S. Rost, S. M. Greenberg, and J. Rosand The Genetic Architecture of Intracerebral Hemorrhage Stroke, July 1, 2008; 39(7): 2166 - 2173. [Abstract] [Full Text] [PDF]

				D. E. Singer, G. W. Albers, J. E. Dalen, M. C. Fang, A. S. Go, J. L. Halperin, G. Y. H. Lip, and W. J. Manning Antithrombotic Therapy in Atrial Fibrillation: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition) Chest, June 1, 2008; 133(6_suppl): 546S - 592S. [Abstract] [Full Text] [PDF]

				W. Rosamond, K. Flegal, K. Furie, A. Go, K. Greenlund, N. Haase, S. M. Hailpern, M. Ho, V. Howard, B. Kissela, et al. Heart Disease and Stroke Statistics--2008 Update: A Report From the American Heart Association Statistics Committee and Stroke Statistics Subcommittee Circulation, January 29, 2008; 117(4): e25 - e146. [Full Text] [PDF]

				T. Deneke, K. Khargi, B. Lemke, T. Lawo, M. Lindstaedt, A. Germing, T. Brodherr, L. Bosche, A. Mugge, A. Laczkovics, et al. Intra-operative cooled-tip radiofrequency linear atrial ablation to treat permanent atrial fibrillation Eur. Heart J., December 1, 2007; 28(23): 2909 - 2914. [Abstract] [Full Text] [PDF]

				M. L. Flaherty, B. Kissela, D. Woo, D. Kleindorfer, K. Alwell, P. Sekar, C. J. Moomaw, M. Haverbusch, and J. P. Broderick The increasing incidence of anticoagulant-associated intracerebral hemorrhage Neurology, January 9, 2007; 68(2): 116 - 121. [Abstract] [Full Text] [PDF]