NOAC better than VKA for elderly patients with atrial fibrillation
Nonvitamin K antagonist oral anticoagulants (NOACs) appear to confer more clinical benefits to elderly patients with atrial fibrillation (AF) than vitamin K antagonist anticoagulants (VKAs), suggests a study, adding that this is primarily driven by the lower rates of major bleeding.
Moreover, major bleeding is numerically lower with NOACs in higher-risk patients with low body mass index (BMI) or age ≥85 years.
“NOAC use is associated with a lower incidence of major bleeding in elderly patients with AF,” researchers said. “Protection from cardiovascular events was also more prominent with the NOACs, with the safety benefits providing the greatest contribution to the improved net clinical outcome observed in the NOAC group.”
This study pooled data on 3,825 elderly patients from the PREFER in AF and PREFER in AF PROLONGATION registries. The incidence of the net composite endpoint, including major bleeding and ischaemic cardiovascular events, on NOACs (n=1,556) vs VKAs (n=2,269) was the primary outcome.
The net composite endpoint rates with NOACs compared with VKAs were 6.6 percent vs 9.1 percent per year (odds ratio [OR], 0.71, 95 percent CI, 0.51–0.99; p=0.042). NOAC therapy correlated with a lower rate of major bleeding relative to VKAs (OR, 0.58, 0.38–0.90; p=0.013). [Am J Med 2019;132:749-757.e5]
There was a nominal reduction in ischaemic events as well (OR, 0.71, 0.51–1.00; p=0.050). Moreover, major bleeding was numerically lower with NOACs in higher-risk patients with low BMI (OR, 0.50, 0.22–1.12; p=0.07) or with age ≥85 years (OR, 0.44, 0.13–1.49, p=0.17).
In a pooled analysis of phase III studies on NOACs in patients with AF, results showed no interaction between clinical benefit of these drugs vs warfarin and age. [Lancet 2014;383:955-962; Circulation 2011;123:2363-2372; Circulation 2014; 130:138-146; Eur Heart J 2014;35:1864-1872; J Am Heart Assoc 2016;5:e003432]
A meta-analysis on elderly patients with AF also reported greater efficacy of NOACs compared to conventional therapy in preventing thromboembolic events, without bleeding excess. [J Am Geriatr Soc 2014;62:857-864]
“However, available data on NOACs in older populations with AF are essentially derived from subgroup analyses of randomized studies that, although often prespecified, have included low numbers of patients,” researchers said.
“Moreover, various conditions at high prevalence in older populations may impact on the efficacy and mainly on the safety of NOACs, for example, hypoalbuminaemia, fluctuations of renal function, low body weight and propensity to gastrointestinal bleeding,” they added.
Furthermore, a small observational study reported low event rates with NOACs in elderly patients who switched from other antithrombotic treatments. [Clin Appl Thromb Hemost 2017;23:58-63]
“Indeed, real-world evidence focused on the net clinical outcome of NOAC utilization in advancing age populations is relevant to address current concerns and better define the specific role of such agents in this expanding setting of patients,” according to researchers. “The analysis here presented is consistent with this need.”