title: Warfarin use in atrial fibrillation patients at low risk for stroke: analysis of the Michigan Anticoagulation Quality Improvement Initiative (MAQI(2)).
abstract: To more accurately quantify the proportion of anticoagulated patients with atrial fibrillation (AF) that may be inappropriately treated with warfarin for stroke prevention. Patients with AF have an increased risk of stroke, which is lowered by the use of warfarin. However there is likely more potential harm than benefit in patients that do not have additional stroke risk factors. Studies have described overuse of warfarin for stroke prophylaxis in lowest risk patients. However, many of those studies did not assess for electrical cardioversion (ECV) or radiofrequency ablation (RFA) as indications for warfarin therapy. Data from 1852 non-valvular AF patients treated with warfarin between October 2009 and October 2011 at seven anticoagulation centers participating in the Michigan Anticoagulation Quality Improvement Initiative registry were analyzed. Low risk AF patients were risk stratified using the CHADS2 scoring systems, with a score of zero representing lowest risk. 193 (10.4 %) of AF patients receiving warfarin were identified as having the lowest risk of stroke by the CHADS2 score. Of the patients with CHADS2 = 0, 130 (67.4 %) had undergone a recent ECV and/or RFA. Of all AF patients, only 63 (3.4 %) had a CHADS2 score of 0 and no recent ECV or RFA. The vast majority of AF patients receiving anticoagulation in this multi-center registry are doing so in accordance with national and international guidelines. In contrast to prior population-based studies, very few low risk patients are receiving inappropriate warfarin therapy for stroke prophylaxis in AF, when procedure-based indications are also considered.
authors: Cardiovascular Center, University of Michigan Health System, Ann Arbor, MI, USA, gbarnes@umich.edu.
authors: Geoffrey D
authors: GD
authors: Barnes
authors: Scott
authors: S
authors: Kaatz
authors: Julia
authors: J
authors: Winfield
authors: Xiaokui
authors: X
authors: Gu
authors: Brian
authors: B
authors: Haymart
authors: Eva
authors: E
authors: Kline-Rogers
authors: Jay
authors: J
authors: Kozlowski
authors: Dennis
authors: D
authors: Beasley
authors: Steve
authors: S
authors: Almany
authors: Tom
authors: T
authors: Leyden
authors: James B
authors: JB
authors: Froehlich
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008824:Michigan / Q000453:epidemiology; D017410:Practice Guidelines as Topic; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology / Q000517:prevention & control*; D014859:Warfarin / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D000925:Anticoagulants; D014859:Warfarin
references: Am Heart J. 2010 Mar;159(3):331-9
references: 20211292
references: J Cardiovasc Electrophysiol. 2004 Aug;15(8):920-4
references: 15333087
references: Am J Med. 2010 May;123(5):446-53
references: 20399322
references: Circulation. 2006 Aug 15;114(7):e257-354
references: 16908781
references: Thromb Haemost. 2010 Feb;103(2):442-9
references: 20076843
references: Eur Heart J. 2006 Dec;27(24):3018-26
references: 16731536
references: Am J Manag Care. 2010 Nov;16(10 Suppl):S278-83
references: 21517642
references: Am J Med. 2001 Jun 15;110(9):694-702
references: 11403753
references: Chest. 2012 Feb;141(2 Suppl):e531S-e575S
references: 22315271
references: Clin Cardiol. 2001 Mar;24(3):238-44
references: 11288971
references: Eur Heart J. 2010 Oct;31(19):2369-429
references: 20802247
references: Am Heart J. 2008 Aug;156(2):374.e1-6
references: 18657673
references: N Engl J Med. 2009 Sep 17;361(12):1139-51
references: 19717844
references: J Thromb Haemost. 2005 Apr;3(4):692-4
references: 15842354
references: J Am Coll Cardiol. 2007 Apr 10;49(14):1561-5
references: 17418296
references: Circulation. 1998 Apr 7;97(13):1231-3
references: 9570191
references: Europace. 2008 Jun;10(6):674-80
references: 18403385
references: J Thromb Thrombolysis. 2013 Jan;35(1):10-4
references: 22797905