Physicians continue to turn to warfarin as an anticoagulant for atrial fibrillation (AF) patients despite the availability of newer drugs, according to an unpublished analysis from the PINNACLE-AF Registry. The analysis, based on more than 121,000 unique AF patients in 2011, found among those prescribed anticoagulants, 87.4 percent were on warfarin.

The American College of Cardiology (ACC) released its first findings from its expanded outpatient registry, the PINNACLE Registry, on Aug. 14 with a focus on AF and the novel oral anticoagulants dabigatran (Pradaxa, Boehringer Ingelheim Pharmaceuticals) and rivaroxaban (Xarelto, Bayer HealthCare/Janssen Pharmaceuticals). The drugs entered the market in late 2010 and late 2011, respectively.

Analysts found that the anticoagulation rate was slightly less than 50 percent, with warfarin dominating. Only 12.6 percent of patients on anticoagulants were prescribed either dabigatran or rivaroxaban.

PINNACLE-AF operates within the existing PINNACLE Registry, which is the largest cardiovascular outpatient database in the U.S., and is part of the ACC’s National Cardiovascular Data Registry (NCDR). NCDR is the most comprehensive, outcomes-based cardiovascular patient data registry for quality improvement in the U.S., according to the ACC.

It is documented in the PINNACLE Registry as well as in the peer-reviewed AF literature that nearly half of all AF patients at moderate to high risk of stroke are not anticoagulated according to current scientific guidelines. In a 2011 study, Chan et al found anticoagulation rates of 55.1 percent in a population of 10,000 patients in the PINNACLE Registry. They reported an “almost random pattern of treatment” when all clinical variables were considered.

The ACC is exploring whether novel oral anticoagulants appear to most often be used as an alternative to warfarin in patients already treated or likely to be treated rather than as an option for patients previously not anticoagulated for stroke prevention. A PINNACLE sub-committee is analyzing these data in preparation for a manuscript that will be submitted for peer review.

“As new treatments for atrial fibrillation come online, assessing shifts in care patterns—and the impact of these shifts on patients—is a top clinical and research priority,” said William J. Oetgen, MD, MBA, senior vice president of science and quality at the ACC, in a release. “We are interested to see if these new medications change the way doctors think about stroke prevention and help us close a long-standing quality gap in anticoagulation."

PINNACLE currently has 4.7 million patient records from hundreds of outpatient practices nationwide. Of those patients, more than 250,000 have AF. Bristol-Myers Squibb and Pfizer provided financial support for the registry.