WASHINGTON – Use of the new oral anticoagulant rivaroxaban to prevent stroke in atrial fibrillation patients doubled and then redoubled during 2010-2013, based on a review of nearly 10,000 atrial fibrillation patients who received their care through a large health network in Wisconsin and Illinois.
Data from 9,652 atrial fibrillation (AF) patients who received care through Aurora Health Care during the 4-year period also showed that two new oral anticoagulants, rivaroxaban (Xarelto) and dabigatran (Pradaxa), seemed roughly comparable to warfarin for preventing strokes and not causing bleeding, including in patients aged 80 years or older, a patient group poorly represented in the pivotal trials of the new drugs, Dr. Anton V. Strunets said at the annual meeting of the American College of Cardiology.
Mitchel L. Zoler/Frontline Medical News
Dr. Anton V. Strunets
"In community-based, real-world practice, use of novel anticoagulants in the older population was substantial and increasing," and the results were also "reassuring" about the efficacy and safety of these drugs during routine use, particularly in the elderly, said Dr. Strunets, a physician on the staff of Aurora Health Care in Milwaukee.
Since 2010, "the type of anticoagulant used has changed dramatically," he said, with the use of warfarin and dabigatran as a percentage of AF patients falling and the use of rivaroxaban rising sharply. After rivaroxaban received Food and Drug Administration approval in 2011 for use in preventing stroke in AF patients, it entered the Aurora practice with roughly 8% of patients on the drug by the end of the year, rising to about 16% in 2012, and up to about 30% by the end of last year. In contrast, about 8% of patients were on dabigatran in 2010, and the level then dropped steadily during the next 3 years, so that last year about 1% of AF patients were on dabigatran. While warfarin remained the most widely used anticoagulant throughout, its share of the treated AF population fell from more than 90% in 2010 to less than 70% in 2013.
These numbers from Aurora matched numbers reported last November from a U.S. registry maintained by the American College of Cardiology, which showed that during June-September 2013, 72% of U.S. AF patients on an anticoagulant received warfarin.
Dr. Strunets cited several factors likely driving shifting anticoagulant use in AF patients, though none were documented by the data he reported: the attraction of once-daily dosing with rivaroxaban to boost compliance, especially in older patients; the coverage allowed by insurers and health plans; and recent concern about dabigatran tied to a new study of the drug’s safety launched by the Food and Drug Administration.
Another facet of oral anticoagulant use at Aurora is that during the 4-year period, 38% of AF patients were 80 years or older, including about 30% of those who received rivaroxaban and 25% of those on dabigatran. The efficacy and safety of treatment, based on the incidence of strokes and of intracranial and gastrointestinal bleeds, were roughly similar in the dabigatran, rivaroxaban, and warfarin subgroups, and the rates for the new anticoagulants also roughly matched the rates seen in the pivotal trials with those drugs, suggesting that the new anticoagulants were performing well when used in octo- and nonagenarians, Dr. Strunets said. But he cautioned that the patients who received rivaroxaban or dabigatran were significantly younger and had significantly lower stroke and bleeding risk scores than patients who received warfarin, a selection bias that may have affected outcomes.
Dr. Strunets and his associates had no disclosures.
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