Trends in antithrombotic therapy for atrial fibrillation: Data from the Veterans Health Administration Health System.
Although controversial, several prior studies have suggested that oral anticoagulants (OACs) are underused in the US atrial fibrillation (AF) population. Appropriate use of OACs is essential because they significantly reduce the risk of stroke in those with AF. In the >2 million Americans with AF, OACs are recommended when the risk of stroke is moderate or high but not when the risk of stroke is low. To quantify trends and guideline adherence, we evaluated OAC use (either warfarin or dabigatran) in a 10-year period in patients with new AF in the Veterans Health Administration.



New AF was defined as at least 2 clinical encounters documenting AF within 120 days of each other and no previous AF diagnosis (N = 297,611). Congestive Heart Failure, Hypertension, Age > 75, Diabetes, and Stroke (CHADS2) scores were determined using age and diagnoses of hypertension, diabetes, heart failure, and stroke or transient ischemic attack during the 12 months before AF diagnosis. Receipt of an OAC within 90 days of a new diagnosis of AF was evaluated using VA pharmacy data.



Overall, initiation of an OAC fell from 51.3% in 2002 to 43.1% in 2011. For patients with CHADS2 score of 0, 1, 2, 3, 4, and 5-6, the proportions of patients prescribed an OAC showed a relative decrease of 26%, 23%, 14%, 12%, 9%, and 13%, respectively (P < .001). Clopidogrel use was stable at 10% of the AF population.



Among US veterans with new AF and additional risk factors for stroke, only about half receive OAC, and the proportion is declining.
Comprehensive Access and Delivery Research and Evaluation Center (CADRE), Iowa City VA Medical Center, Iowa City, IA. Electronic address: joshua-buck@uiowa.edu.
Joshua
J
Buck
Comprehensive Access and Delivery Research and Evaluation Center (CADRE), Iowa City VA Medical Center, Iowa City, IA; Department of Internal Medicine, Roy and Lucille J. Carver College of Medicine, University of Iowa, Iowa City, IA.
Peter
P
Kaboli
Department of Internal Medicine, Washington University in St. Louis, St. Louis, MO.
Brian F
BF
Gage
Division of General Internal Medicine, University of Toronto, Toronto, ON, Canada.
Peter
P
Cram
Comprehensive Access and Delivery Research and Evaluation Center (CADRE), Iowa City VA Medical Center, Iowa City, IA; Department of Internal Medicine, Roy and Lucille J. Carver College of Medicine, University of Iowa, Iowa City, IA. Electronic address: mary-vaughan-sarrazin@uiowa.edu.
Mary S
MS
Vaughan Sarrazin
D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use; D000991:Antithrombins / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000150:complications / Q000188:drug therapy*; D000077144:Clopidogrel; D000069604:Dabigatran / Q000627:therapeutic use*; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D019983:Guideline Adherence; D006333:Heart Failure / Q000453:epidemiology; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D002546:Ischemic Attack, Transient / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D017410:Practice Guidelines as Topic; D012306:Risk; D018570:Risk Assessment; D020521:Stroke / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D014481:United States; D014493:United States Department of Veterans Affairs; D014859:Warfarin / Q000627:therapeutic use*
D000925:Anticoagulants; D000991:Antithrombins; D010975:Platelet Aggregation Inhibitors; D014859:Warfarin; D000077144:Clopidogrel; D000069604:Dabigatran; D013988:Ticlopidine