A recent study published in the Journal of the American Medical Directors Association reports that direct oral anticoagulants (DOACs) were associated with higher bleeding risk vs dicumarol, a vitamin K antagonist (VKA), in oldest old patients (aged ≥75 years) with nonvalvular Afib. DOACs were reported to be more effective than warfarin with similar major bleeding rates in patients aged ≥75 years by a network meta-analysis of phase 3 trials. Authors of this study infer that their observations could be because of worse clinical profile of patients. They call for close monitoring of DOAC prescription in this patient category.
554 outpatients (aged ≥75 years) with nonvalvular Afib, initiated on oral anticoagulants, were evaluated. 193 patients received dicumarol whereas 203, 112 and 46 received dabigatran (110/150 mg twice daily), rivaroxaban (15/20 mg once daily) or apixaban (2.5/5 mg twice daily), respectively.
DOACs vs dicumarol was associated with a higher risk for bleeding (HR, 1.60; 95% CI, 1.04-2.44) and heavy bleeding (HR, 2.22; 95% CI, 0.88-5.59). After adjusting for clinical characteristics, excess risk for bleeding associated with DOACs vs dicumarol disappeared yielding corresponding figures of (aHR, 1.19; 95% CI, 0.68-2.08) and (aHR, 1.01; 95% CI, 0.35-2.93) for bleeding and major bleeding, respectively. Incidence (per 100 patient-years) of major bleeding for dicumarol, dabigatran, rivaroxaban and apixaban was 3.3 (95% CI, 1.3%-5.3%), 5.4 (95% CI, 2.5%-8.3%), 5.4 (95% CI, 1.1%-9.7%) and 2.7 (95% CI, 2.6%-8.2%) respectively.
Authors comment, “Future research in very old patients should focus on better defining risk factors for anticoagulant-associated bleeding.” They further add, “Type of DOAC that is most appropriate according to the clinical characteristics of each patient should be defined.”
