Trends in the pharmacologic management of atrial fibrillation: data from the Veterans Affairs health system Mary S. Vaughan Sarrazin PhD, Alexander Mazur MD, Elizabeth Chrischilles PhD, Peter Cram MD, MBA PII: DOI: Reference:

S0002-8703(14)00223-3 doi: 10.1016/j.ahj.2014.03.024 YMHJ 4615

To appear in:

American Heart Journal

Received date: Accepted date:

9 January 2014 17 March 2014

Please cite this article as: Vaughan Sarrazin Mary S., Mazur Alexander, Chrischilles Elizabeth, Cram Peter, Trends in the pharmacologic management of atrial fibrillation: data from the Veterans Affairs health system, American Heart Journal (2014), doi: 10.1016/j.ahj.2014.03.024

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ACCEPTED MANUSCRIPT Trends in the pharmacologic management of atrial fibrillation: data from the Veterans Affairs health system Short Title: Trends in management of atrial fibrillation

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Authors:

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Mary S. Vaughan Sarrazin, PhDa,b Alexander Mazur, MDc

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Elizabeth Chrischilles, PhDd

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Peter Cram, MD, MBAa,b

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a: Comprehensive Access and Delivery Research and Evaluation Center (CADRE), Iowa City VA Medical Center, Iowa City, IA 52246

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b: General Internal Medicine, Roy and Lucille J. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242

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c: Cardiovascular Medicine, Roy and Lucille J. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242

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d: Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, Iowa 52242

Address correspondence to: Mary S. Vaughan Sarrazin Comprehensive Access and Delivery Research and Evaluation (CADRE) Center Iowa City VA Medical Center 601 Highway 6 West – (Research 152) Iowa City, IA 52246 Email: [email protected] Fax: 319-877-4932

Word Count: 2,883

Abstract Word Count: 214

Key Words: atrial fibrillation, antiarrhythmic drugs, arrhythmia, temporal trends

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ACCEPTED MANUSCRIPT Acknowledgments: This work was supported by a Mentored Career Enhancement Award in Patient Centered Outcomes Research (PCOR) for Mid-Career and Senior Investigators (K18)

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provided to Dr. Vaughan Sarrazin by the Agency for Healthcare Research and Quality (AHRQ),

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and by the Health Services Research and Development Service (HSR&D) of the Department of Veterans Affairs. The authors do not have any conflicts of interest or financial relationships related

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to the content of this manuscript. The authors had full access to and take full responsibility for the integrity of the data. The views expressed in this article are those of the authors and do not

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necessarily represent the views of the Department of Veterans Affairs.

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ACCEPTED MANUSCRIPT ABSTRACT: Background: Prescribing rate control medications with or without antiarrhythmic drugs

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is often the first course treatment for atrial fibrillation (AF). Clinical trial data suggest

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that antiarrhythmic drugs are only marginally effective and have multiple drawbacks, while rate control alone is sufficient for most patients with minimally symptomatic AF.

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Objectives: This study investigates changes in the use of oral rate and rhythm control

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therapy for AF during years 2002-2011 in the U.S. Veterans Health Administration (VHA).

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Methods: Patients with new AF episodes were identified in VHA administrative data files and receipt of oral rate and rhythm controlling drugs within 90 days of new AF

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episodes was determined for each patient.

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Results: The percentage of patients receiving an oral rate controlling medication decreased from 74.9% in 2002-2003 to 70.9% in 2010-2011. The use of digoxin

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decreased by over 50%, while the use of beta blockers metoprolol and carvedilol

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increased. The proportion of patients receiving any oral antiarrhythmic medication decreased from 13.5% in 2002-2003 to 11.6% in 2010-2011 and use of the most frequently prescribed oral antiarrhythmic, amiodarone, decreased by 17%. Conclusions: Rate control remains the dominant strategy for treating new AF. The decrease in the use of oral antiarrhythmics may be due to lack of concrete data suggesting mortality and morbidity benefit as well as increasing utilization of the ablation approach.

Bullet points: The proportion of patients with new AF episodes who were prescribed oral rate or rhythm control medications decreased modestly from 2002 through 2011. 3

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The use of digoxin decreased by over 50%, and amiodarone decreased by 17%. Rate control remains the dominant strategy for treating new AF.

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ACCEPTED MANUSCRIPT INTRODUCTION Atrial fibrillation (AF) affects up to 1% in the general population1 and 6% in

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persons 65 years of age and older.2 Moreover, the number of patients with AF in the

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United States (US) is projected to rise due to the aging population and epidemics in other risk factors such as obesity, diabetes, hypertension and heart failure.3 AF is

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associated with a five-fold increase in costs of medical care,4 and a number of

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complications including heart failure, cardiomyopathy, and an increased risk of stroke.5 Management of AF includes pharmacologic and non-pharmacologic interventions

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to restore and maintain normal sinus rhythm, and/or control ventricular rate. In patients with symptomatic AF the rhythm control approach is usually attempted while in patients

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with asymptomatic or minimally symptomatic AF, antiarrhythmic drugs may be avoided

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and the rate control approach is an acceptable strategy.6, 7 It is well recognized that available antiarrhythmic medications are only marginally effective at maintaining sinus

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rhythm and have significant side effects. A number of large randomized clinical studies

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comparing oral rate and rhythm control strategies in patients with asymptomatic or minimally symptomatic AF showed no difference in major mortality and morbidity outcomes including death, stroke and hospital admissions.8-11 More recently, similar outcomes associated with rate and rhythm control strategies were found in a population of AF patients with concomitant heart failure secondary to left ventricular systolic dysfunction.12 To determine the impact of the above trials on pharmacological management of AF, we examined contemporary trends in the use of oral rate control and rhythm control therapy for AF between fiscal years (FY) 2002 and 2011 in a large US integrated healthcare delivery system- the Veterans Administration Healthcare System. 5

ACCEPTED MANUSCRIPT Specifically, we evaluated changes in the use of oral rate or rhythm controlling agents within 90 days of a new AF episode, overall and by specific drug. Analyses controlled

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ablation and pharmacologic or electrical cardioversion.

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for patient characteristics as well as the use of related therapies such as cardiac

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METHODS:

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Patients: We identified patients with AF newly diagnosed between October 1, 2001 and September 30, 2011 using the VA Outpatient Care files and Inpatient

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Treatment Files (ICD-9-CM diagnosis code 427.31). Patients were deemed to have AF if they had at least two encounters with a primary or secondary AF diagnosis within 120

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days of each other. Episodes were deemed new if the patient had no other AF-related

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encounters during the 12 months prior. A total of 406,168 episodes met these criteria. Episodes in which patients were not receiving care in the VA for at least 12 continuous

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months prior to the AF diagnosis date were excluded (n=94,561) because this lack of

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enrollment precluded us from knowing that the AF episode was truly new. In addition, approximately 1% of patients had more than one eligible AF episode during the study period (i.e., patients had two or more AF episodes separated by at least 12-months). We selected the first episode for patients with multiple episodes, leaving 297,611 episodes during the 10-year period. Finally, 20,635 episodes that were preceded by oral antiarrhythmic medication or pharmacologic or electric cardioversion within 90 days prior to the AF diagnosis were excluded, leaving 275,559 eligible episodes. Variable Definition: We searched VA Decision Support System (DSS) National Pharmacy Extracts for prescriptions filled by VA pharmacies. Drugs were identified by the VA identification number (IEN), which corresponds to national drug codes 6

ACCEPTED MANUSCRIPT associated with generic names of drugs. Three types of rate control medications were identified with input and guidance from the clinicians (AM and PC) and pharmacist (EC)

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involved in this project. Medications were classified according to mechanism of action:

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Beta Blockers (eg. atenolol, carvedilol, metoprolol, propranolol), Calcium Channel Blockers (e.g., diltiazem, verapamil), and digoxin. Oral rhythm-controlling medications

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included amiodarone, dofetilide, dronedarone, flecainide, profafenone, sotalol,

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disopyramide, and quinidine. We confirmed that all oral medications were in doses approved for maintenance therapy due to the fact that some antiarrhythmics

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(e.g.,flecainide) have been approved for cardioversion in high doses. We defined the use of each medication type as a binary variable indicating any use within 90 days of

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the AF diagnosis date.

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Patients’ demographic characteristics were identified using information in the VA administrative data, including age, sex, race (categorized as white, black, Hispanic,

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other non-white, and missing), region of the country where the patient resided

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(categorized as Northeast, South, Midwest, and West), and VA enrollment priority (categorized as patients with service connected disabilities, low income, and other). Patient comorbid conditions were identified on inpatient and outpatient claims during the 12 months prior to the AF diagnosis date. Using algorithms originally developed by Elixhauser et al13 and updated by Quan et al,14 we identified the presence of 31 possible comorbid conditions (e.g., diabetes, hypertension, renal disease). Additional conditions relevant to AF were identified, including other dysrhythmias (ICD-9-CM codes 427.xx, excluding 427.31), cardiomyopathy (ICD9 codes 425.x), cardiac conduction disorder (e.g., bundle branch block; ICD9 codes 426.x), previous implantable pacemaker (ICD9 codes V45.01 and V53.31) and previous implantable 7

ACCEPTED MANUSCRIPT cardiac defibrillator (ICD9 code V45.02 and V53.32). Previous cerebrovascular events were identified using a previously published algorithm and included cerebral infarction

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(ICD-9-CM codes 433.01, 433.11, 433.21, 433.31, 433.81, 433.91, 434.01, 434.11,

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434.91) and transient ischemic attacks (ICD-9-CM code 435.x).15 We also calculated the CHADS score for each patient, as has been done in prior studies based on

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administrative data.15, 16 This score represents the risk of stroke based on a point

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system reflecting the presence of congestive heart failure (1 point), hypertension (1 point), age 75 or older (1 point), diabetes (1 point), and previous stroke (2 points).

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Statistical Analysis: Characteristics of patients with AF episodes during FY20022003 and FY2010-2011 were compared using chi-square statistics and analysis of

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variance. The proportion of patients receiving at least one medication in each

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medication category and the proportions receiving individual medications were calculated in two-year increments over the study period. Trends in the use of each

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medication type as well as medication combinations were evaluated using the Cochran-

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Armitage Test for Trend.17 Additional analysis used logistic regression to estimate risk adjusted rates of medication use while controlling for patient demographic and comorbid conditions, using a statistical criterion of p30%) observed for hypertension with complications, conduction disorders, renal failure, prior ICD and pacemaker receipt.

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There were no large (>30%) relative decreases in comorbid conditions. Finally, the use

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of electrical cardioversion decreased by 13% while the use of pharmacologic cardioversion increased modestly. All comparisons were statistically significant (p

Trends in the pharmacologic management of atrial fibrillation: Data from the Veterans Affairs health system.

Prescribing rate control medications with or without antiarrhythmic drugs is often the first course treatment for atrial fibrillation (AF). Clinical t...
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