Concerns About the Use of New Oral Anticoagulants for Stroke Prevention in Elderly Patients with Atrial Fibrillation

Abstract

The prevalence of atrial fibrillation (AF) and the embolic risk increase with age. Elderly AF patients are undertreated with vitamin K antagonists (VKA). The new oral anticoagulants (NOAC) dabigatran, rivaroxaban and apixaban have been shown to be non-inferior to VKA for stroke prevention in AF. We summarize the knowledge about primary and secondary stroke prevention by NOAC in AF patients >75 years of age. A literature search was carried out using the terms 'dabigatran', 'rivaroxaban', 'apixaban', 'elderly', 'octogenarians', 'atrial fibrillation' and 'anticoagulation' from 1998 to 2013. Randomized clinical trials, longitudinal studies, case series and case reports were included. Whereas studies investigating the use of VKA for stroke prevention in the 1990s were carried out by industry-independent institutions, all NOAC-investigating trials were sponsored by the manufacturers of the respective drugs. Frail elderly people were not represented in NOAC-investigating trials because of various exclusion criteria, and only one-third of patients were aged >75 years. A subgroup analysis from the dabigatran-investigating trial indicated that elderly patients might have a higher risk for extracranial bleeding complications with NOAC than with VKA. Further concerns about the use of NOAC in the elderly are the high prevalence of renal insufficiency in AF patients >75 years of age, the largely unknown risk of drug-drug and drug-food interactions, the lack of easily available laboratory monitoring tests of anticoagulant activity and the lack of an antidote. There is a need for independent studies comparing the efficacy and risk of side effects of NOAC with that of VKA in elderly AF patients.