April 4, 2016 – The study confirmed that apixaban is superior to warfarin for preventing serious outcomes, regardless of when a patient received the AF diagnosis.
Patients with recently diagnosed atrial fibrillation (AF) are just as likely as patients with longstanding AF to experience a stroke, and are at greater risk of death. However, AF patients who receive the anticoagulant apixaban are less likely to experience a stroke or bleeding regardless of when they received their diagnosis.
In a new study, the DCRI’s Patrícia O. Guimarães, MD, (pictured) and her colleagues analyzed clinical outcomes among patients with recent and
remote diagnoses of AF. They also examined the efficacy and safety of apixaban versus warfarin in patients with recently diagnosed AF.
Guimarães presented their findings Monday at the annual Scientific Sessions of the American College of Cardiology in Chicago.
Because AF patients are at greater risk of stroke, current clinical guidelines recommend anticoagulation therapy. However, the studies that informed those guidelines contained few patients with recently diagnosed AF. In this study the DCRI researchers sought to determine if the risk of stroke outweighed the risk of bleeding for recently diagnosed AF patients on anticoagulant therapy, and if apixaban is as effective in this population as it is in patients with remote diagnoses of AF.
To do so, they examined data from the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial. That trial compared apixaban with warfarin in primary and secondary prevention of thrombo-embolism in AF patients. Defining recently diagnosed AF as a new diagnosis of AF within 30 days prior to enrollment, the researchers analyzed the efficacy and safety of apixaban and warfarin according to time since AF diagnosis.
Of the 18,140 patients enrolled in ARISTOTLE, 1,899 (10.5 percent) patients had recently diagnosed AF. Patients with recently diagnosed AF had a similar risk of stroke at patients with remotely diagnosed AF (HR 1.07, 95 percent CI 0.80–1.42; p=0.67) but were at greater risk of death (adjusted HR 1.21, 95 percent CI 1.02–1.43; p=0.03), a finding that surprised the researchers.
“We were not expecting this finding,” Guimarães said. “Even after adjusting for potentially confounding factors, we got the same result. It’s definitely intriguing.”
The effects of apixaban in reducing stroke and systemic embolism were also found to be consistent with ARISTOTLE’s original conclusion: that apixaban is superior to warfarin for preventing major bleeding, stroke, and even death, regardless of when a patient received his or her AF diagnosis.
This study, Guimarães said, demonstrated that recently diagnosed AF patients should not be considered low risk by their physicians.
In addition to Guimarães, the study’s other Duke authors included Daniel M. Wojdyla, MS; John H. Alexander, MD, MHS; Laine Thomas, PhD; Sana M. Al-Khatib, MD, MHS; Christopher B. Granger, MD, and Renato D. Lopes, MD, MHS, PhD.