Effect of the 2014 Atrial Fibrillation Guideline Revisions on the Proportion of Patients Recommended for Oral Anticoagulation

In 2014, the American Heart Association, American College of Cardiology, and Heart Rhythm Society published a revised guideline for atrial fibrillation (AF) treatment recommending use of a refined stroke risk score and revised threshold for oral anticoagulation (OAC) initiation.¹ We assessed the potential effect of this new guideline by comparing the proportion of patients with AF recommended for OAC under the 2011 and 2014 guidelines.^1,2

We used data from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) study, a national, prospective, outpatient registry of AF in patients 18 years or older at 176 sites in the United States.³ The primary outcome was the proportion of patients recommended for OAC at baseline under each guideline. The CHADS₂ score, recommended for stroke risk assessment by the 2011 guideline, incorporates information on prior stroke and transient ischemic attack, congestive heart failure and dysfunction, hypertension, age of 75 years or older, and diabetes mellitus (score range, 0-6).⁴ The revised 2014 guideline recommends use of the CHA₂DS₂-VASc score, which increases the point value from 1 to 2 for age of 75 years and older and adds elements for female sex, vascular disease, and age of 65 through 74 years (score range, 0-9).⁵ We considered only those patients with a definitive recommendation to be OAC recommended (CHADS₂ score≥2 under the 2011 guideline² and CHA₂DS₂-VASc score ≥2 under the 2014 guideline¹). We also examined changes in recommendations according to age (<65 and ≥65 years) and sex. We used Pearson χ² tests to compare the proportions.

From May 29, 2010, through August 8, 2011, a total of 10 132 patients were enrolled in ORBIT-AF (age, median [IQR], 75 years [67-82 years]; 42.3% female). The overall proportion of patients recommended for OAC increased by 19.0% from 71.8% (95% CI, 70.9%-72.7%) under the 2011 guideline to 90.8% (95% CI, 90.2%-91.4%) under the 2014 guideline (P < .001; Figure). For patients younger than 65 years, the proportion recommended for OAC increased from 43.1% to 60.6%, whereas the proportion recommended for patients 65 years or older increased from 79.1% to 98.5%. Among women, the percentage recommended increased from 76.7% to 97.7%.

Of 1926 patients who were newly recommended for OAC, 43.6% were reclassified because of a single risk factor, 49.5% because of 2 risk factors, and 6.9% because of 3 risk factors. Female sex was a contributing factor for 46.8% of patients who were reclassified, age for 81.4%, and vascular disease for 35.1%. Among those reclassified because of a single risk factor, 20.7% were reclassified because of female sex, 63.8% because of age, and 15.5% because of vascular disease. Extrapolating under the assumption that the stroke risk distribution in ORBIT-AF is representative of that of the broader US AF population, adoption of the 2014 guideline could result in reclassification of 988 500 individuals as newly recommended for OAC (Table).

The 2014 AF treatment guideline revision substantially increases the proportion of patients recommended for OAC, with near-universal indication for women and for patients older than 65 years. Under the 2014 guideline, 2 of 3 patients with AF who were not previously recommended for OAC were reclassified as being recommended for OAC. The increase in patients with AF who were recommended for OAC is due to adoption of the CHA₂DS₂-VASc score, which was created to better identify patients with AF with truly low risk of stroke by incorporating information on female sex, younger age, and vascular disease.⁵ Although a previous analysis⁶ suggested that CHA₂DS₂-VASc has superior discrimination compared with CHADS₂ in low-risk patients, the 2014 guideline authors acknowledge that ongoing refinement of methods to estimate thromboembolic risk in AF is needed.

Two-thirds of patients with AF who were previously not recommended for OAC are newly recommended under the 2014 guideline. Future studies evaluating longitudinal changes in anticoagulation treatment patterns and outcomes among patients reclassified by the new guideline are warranted.

Corresponding Author: Emily O'Brien, PhD, The Duke Clinical Research Institute, 2400 Pratt St, Room 0311, Terrace Level, Durham, NC 27705 (emily.obrien@duke.edu).

Published Online: March 2, 2015. doi:10.1001/jamainternmed.2015.13.

Author Contributions: Dr O’Brien had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: O’Brien, Hess, Kowey, Fonarow, Piccini.

Acquisition, analysis, or interpretation of data: O’Brien, Kim, Hess, Fonarow, Piccini, Peterson.

Drafting of the manuscript: O’Brien, Kim, Hess, Kowey.

Critical revision of the manuscript for important intellectual content: O’Brien, Hess, Kowey, Fonarow, Piccini, Peterson.

Statistical analysis: O’Brien, Kim, Peterson.

Obtained funding: Piccini.

Study supervision: O’Brien, Kowey, Piccini.

Conflict of Interest Disclosures: Dr O’Brien has reported receiving research support from Janssen Pharmaceuticals Inc and serving as a consultant and on the advisory board for Modest and Portola Pharmaceuticals Inc. Dr Fonarow has reported working as a consultant or on the advisory board for Modest and Ortho-McNeil Pharmaceutical. Dr Piccini has reported receiving research support from Boston Scientific Corporation and Janssen Pharmaceuticals Inc and providing consultancies to Forest Laboratories, Janssen Pharmaceuticals Inc, and Medtronic Inc. Dr Peterson has reported receiving research support from Eli Lilly & Company and Janssen Pharmaceuticals Inc. No other disclosures were reported.

Funding/Support: The ORBIT-AF registry is sponsored by Janssen Scientific Affairs LLC, Raritan, New Jersey. This project was supported in part by cooperative agreement 1U19 HS021092 from the Agency of Healthcare Research and Quality. Drs Piccini and Peterson receive research support as principal investigators for the ORBIT-AF registry.

Role of the Funder/Sponsor: The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and the decision to submit the manuscript for publication. All authors reviewed and agree with the content, including the sponsor.

Additional Contributions: We acknowledge the following individuals for their important contributions to this letter: James V. Freeman, MD, Laine Thomas, PhD, Jack E. Ansell, MD, Elaine M. Hylek, MD, Paul S. Chan, MD, Alan S. Go, MD, Kenneth W. Mahaffey, MD, and Paul Chang, MD. We also thank the ORBIT-AF Registry staff and participants for their important contributions to this work. Drs Ansell, Hylek, Go, and Mahaffey are compensated for their leadership as members of the ORBIT-AF Executive Committee. Dr Chang is an employee of Janssen. None of the contributors were compensated for their review of the manuscript or provision of critical feedback to the coauthors.