Warfarin does not increase mortality risk among hemodialysis (HD) patients with atrial fibrillation (AF), according to what researchers believe is the first prospective study on the subject.
The oral anticoagulant therapy (OAT) was linked to a 4-fold increased risk of bleeding, and it did not reduce the incidence of ischemic stroke. Results also showed that a history of hemorrhagic events doubled the risk of hemorrhage.
“Our findings confirm that HD patients are at high risk for both thrombosis and bleeding, and that any OAT treatment needs to be performed with great care,” stated Simonetta Genovesi, MD, of the University of Milano-Bicocca in Italy, and colleagues. “In particular, warfarin should not be administered in patients with previous bleeding episodes occurring in the presence or even in the absence of OAT.”
The investigators evaluated the effects of OAT in 134 of 290 HD patients with AF from 10 Italian centers who had paroxysmal, persistent, or permanent AF. During a 2-year period, 115 patients died, only 4 from stroke (3 hemorrhagic, 1 ischemic). Of the 115 patients, 51 received OAT and 64 did not.
Unlike OAT, antiplatelet therapy (e.g., aspirin, ticlopidine, and clopidogrel) was associated with a 71% increased risk of death, the researchers reported in Nephrology Dialysis Transplantation (2015;30:491-498). The investigators suggest the higher prevalence of ischemic heart disease in patients taking antiplatelets could make them more vulnerable.
Continuous warfarin use was associated with better survival compared with discontinuing the medication for reasons such as bleeding (69% vs. 50%). Warfarin might not be the sole factor in better outcomes, however, the researchers suggest.
“These results emphasize the need to identify effective interventions that go beyond anticoagulation to reduce further high mortality in the AF population,” the investigators stated.
Previous retrospective studies on the subject have yielded conflicting results. The researchers urge larger prospective studies and randomized trials to assess the risks and benefits of warfarin and determine best practices for preventing stroke and bleeding in high-risk AF patients on HD.
A strength of the study was the use of computed tomography or magnetic resonance imaging to document whether cerebrovascular events were ischemic or hemorrhagic; a limitation of the study was its non-randomized design.