Patients with valvular atrial fibrillation who start taking direct oral anticoagulants (DOACs) have a lower risk of systemic embolism or ischemic stroke than new warfarin users. This is what emerges from a new analysis published on Annals of Internal Medicine by University of Pennsylvania researchers.
Atrial fibrillation is the most frequent arrhythmia found in daily clinical practice according to the latest estimates, with a prevalence of 1.85% in Italy, that is, more than one million affected patients and about 120,000 new cases per year. It involves severe brain and cardiovascular risks such as stroke, heart failure and sudden death.
The advantages of anticoagulants
Patients with atrial fibrillation are recommended to follow prophylactic anticoagulant therapy to protect themselves from an increased risk of stroke and other thromboembolic events. Before the arrival of direct oral anticoagulants, the ‘therapeutic pillar’ for stroke prevention was represented by warfarin which, however, has a number of disadvantages including – the researchers write in the study – “a narrow therapeutic window, dose variability – response and many interactions with drugs and food “. In contrast, Doacs have a fairly short half-life, fewer interactions with other drugs and none with food, an easier-to-manage dosage, and do not require continuous monitoring with laboratory tests.
The other comparative studies
In previous randomized clinical trials, the use of anticoagulants demonstrated similar or superior antithrombotic effects to warfarin in patients with atrial fibrillation and a lower risk of bleeding, but excluded or underrepresented patients with valvular heart disease. “This analysis, however – he explains Ghadeer K. Dawwas, of the Department of Biostatistics, Epidemiology, and Computer Science at the University of Pennsylvania’s Perelman School of Medicine – focused on patients with atrial fibrillation and concomitant valve abnormalities. This subpopulation of subjects is at greater risk of adverse outcomes since valvular diseases increase the possibility of a stroke independent of atrial fibrillation, ”the researchers specify.
The subgroup analysis
The cohort study of University of Pennsylvania researchers was conducted by analyzing data from 56,336 patients with valvular atrial fibrillation collected from January 1, 2010 to June 30, 2019 and new users of Doacs. Most of the patients were in their 70s or 80s, and about half were men. Researchers matched data from patients on anticoagulants with those on warfarin and followed them until the end of the study or until they temporarily or permanently stopped receiving treatment, changed their therapy, or experienced one. outcomes of the study which included the occurrence of ischemic stroke, systemic embolism and / or intracranial or gastrointestinal bleeding.
The efficacy results of the new drugs
The study authors report that the use of anticoagulants, compared with that of warfarin, was associated with a lower risk of major bleeding events and ischemic stroke or systemic embolism. The primary efficacy outcome was a composite of ischemic stroke or SE, while the primary safety outcome was a composite of intracranial or gastrointestinal bleeding. At the end of the study, 787 patients on DOAC had a stroke or systemic embolism after a median follow-up of 134 days (3.9 events per 100 person-years) compared with 1,211 patients on warfarin after one follow-up. median up of 124 days (6.0 events per 100 person-years). Regarding the risk of major bleeding, 1,465 Doac users had one event (compared with 2,155 warfarin users.
New directions for use
“The results were largely similar for the different Doacs with the exception of a nonsignificant efficacy benefit for dabigatran over warfarin,” Dawwas and colleagues write. “This is consistent with another small study, but we don’t know if this observed benefit is due to the small number of patients who received dabigatran or to a real difference in efficacy.” Although this study is based on a relatively short follow-up and the severity of the patients involved is not known, the findings are considered important. “The results of this large observational analysis support the use of DOACs in patients with valvular atrial fibrillation for the prevention of ischemic stroke or systemic embolism, without concern for adverse bleeding complications,” the authors conclude.
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