Treatment of High-Risk AF Patients Often Falls Short of Guidelines

As the number of stroke risk factors increases, so does the prevalence of oral anticoagulation (OAC) prescription in atrial fibrillation (AF) patients, according to a new study.

“However, there appeared to be a plateau effect, such that those patients at the highest risk of stroke still did not receive oral anticoagulation as much as guidelines would expect,” said study lead author Jonathan Hsu, MD, MAS, of the division of cardiology, University of California, San Diego.
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In the cross-sectional study of 4,29,417 outpatients with AF enrolled in the American College of Cardiology National Cardiovascular Data Registry’s PINNACLE Registry between Jan. 1, 2008, and Dec. 30, 2012, the researchers calculated patients’ CHADS₂ score and the CHA₂DS₂-VASc score as a measure of stroke risk. Using multinomial logistic regression models adjusted for patient, physician, and practice characteristics, they examined the association between increased stroke risk score and prescription of an OAC.

The researchers found prescribed treatment consisted of an OAC (192,600 [44.9%]), aspirin only (111,134 [25.9%]), aspirin plus a thienopyridine (23,454 [5.5%]), or no antithrombotic therapy (102,229 [23.8%]).

Each 1-point increase in risk score was associated with increased odds of OAC prescription compared with aspirin-only prescription using the CHADS₂ score (adjusted odds ratio, 1.158; 95% CI, 1.144-1.172; P<.001) and the CHA₂DS₂-VASc score (adjusted odds ratio, 1.163; 95% CI, 1.157-1.169; P<.001). Overall, OAC prescription prevalence did not exceed 50% even in higher-risk patients with a CHADS₂ score exceeding 3 or a CHA₂DS₂-VASc score exceeding 4.

“Certainly it was surprising that cardiovascular specialists who should be well-versed in guideline recommendations and best-care practice did not appear to prescribe oral anticoagulation as much as would be expected in this real-world study of a large United States population of atrial fibrillation patients,” Hsu said. “This highlights a true gap in appropriate care that needs attention for methods of future improvement.”

The biggest message from the study is all clinicians have a responsibility to reduce the risk of stroke in at-risk patients with AF, he said. “If the benefits of oral anticoagulation outweigh the risks of bleeding, there is a clear recommendation to prescribe these medications. We as cardiologists, general practitioners, and neurologists need to make sure we work together to treat AF patients appropriately.”

Future areas of research will include how uptake of the direct OAC (instead of warfarin) will affect the prevalence of OAC prescription in at-risk patients with AF, Hsu said.

“It will be interesting to see if these newer agents will increase the prevalence of oral anticoagulant prescription and narrow ‘the gap’ that we have highlighted in this study,” he said.

-Mike Bederka

Reference:

Hsu JC, Maddox TM, Kennedy KF, et al. Oral anticoagulant therapy prescription in patients with atrial fibrillation across the spectrum of stroke risk: insights from the NCDR PINNACLE Registry. JAMA Cardiol. [epub ahead of print] March 16, 2016. doi:10.1001/jamacardio.2015.0374.