ROME – The new oral anticoagulants performed as advertised in a real-world, Danish registry of more than 40,000 patients with atrial fibrillation.
During the first year on anticoagulant treatment, patients who received a new oral anticoagulant (NOAC) had an ischemic stroke rate similar to that of patients who received the traditional oral anticoagulant, warfarin, but a significantly reduced rate of intracranial hemorrhage, Laila Stærk, MD, reported at the annual congress of the European Society of Cardiology.
These results “reinforce what we have seen in the clinical trials, but with the strength of looking in the entire Danish population,” said Dan Atar, MD, a cardiologist and professor of medicine at the University of Oslo.
“It is enlightening and very reassuring to have these real-world, unselected, registry data. They provide reassurance about safety and efficacy” when prescribing a NOAC, Dr. Atar said in an interview.
The study reported by Dr. Stærk and her associates included 43,299 Danish patients who were recently diagnosed with nonvalvular atrial fibrillation and started on treatment with an oral anticoagulant during the period August 2011 (when the first NOAC, dabigatran, became available for routine use in Denmark) through December 2015. During this period, 42% of these patients received warfarin, 29% received dabigatran (Pradaxa), 16% received apixaban (Eliquis) and 13% received rivaroxaban (Xarelto).
In a propensity-score type of analysis that controlled for baseline differences in clinical and demographic parameters, the results showed that the rate of ischemic stroke during the first year on treatment ranged from 2.0% to 2.5% in the four subgroups based on the anticoagulant received with no statistically-significant differences among the four subgroups. In other words, all three NOACs had efficacy profiles similar to those of warfarin, said Dr. Stærk, a cardiology researcher at Herlev and Gentofte University Hospitals in Hellerup, Denmark.
But on the safety side, all three NOACs were linked with lower rates of intracranial hemorrhages during the 1-year follow-up compared with the patients who received warfarin. In the cases of dabigatran and apixaban, the reduced intracranial hemorrhage rates were statistically significant, with a 0.6% rate among the patients on warfarin and rates that were reduced by a relative 34% for patients who received dabigatran and by a relative 20% among those on apixaban. Rivaroxaban linked with a 13% relative risk reduction in intracranial hemorrhage that was not statistically significant.
Dr. Atar said he would not make comparisons among the three NOACs based on these data, but rather interpreted the finding as showing that collectively the three NOACs assessed had comparable efficacy but better safety compared with warfarin.
He also noted that the Danish registry data document the transition that occurred during 2011 to 2015 in anticoagulant prescribing that shifted from warfarin to NOACs, with 57% of atrial fibrillation patients receiving a NOAC. In Norway, NOAC prescriptions for atrial fibrillation patients recently pulled ahead of warfarin prescription rates, Dr. Atar said. Reassuring data such as those in this report will help to further drive the shift from warfarin to NOACs, and he predicted that soon NOACs will be the anticoagulants used to treat the overwhelming majority of patients with nonvalvular atrial fibrillation.
Dr. Stærk has received research funding from Boehringer Ingelheim, the company that markets dabigatran (Pradaxa). Dr. Atar said that he has been a consultant to and has received research funding from several drug companies.
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