Is it safe to prescribe OACs to older patients with AF?

Older patients who are taking oral anticoagulants (OAC) for atrial fibrillation (AF) benefit from a reduced risk of stroke and all-cause mortality, reports a study. Moreover, nonvitamin K oral anticoagulants (NOAC) exhibit superiority over vitamin K agonists (VKA), with less mortality and major bleeding among its users.

“This study helps alleviate concerns regarding prescribing OACs for AF patients aged ≥75 years,” the researchers said. “OACs, as prescribed in everyday practice to this patient group, may reduce all-cause mortality and stroke with no significant increase in major bleeding, as compared with no anticoagulants.”

A total of 52,018 patients with newly diagnosed AF were recruited into GARFIELD-AF, a prospective observational registry, and followed up for 24 months. Of these, 32.6 percent were aged 65‒74 years, 29.3 percent were 75‒84 years, and 7.9 percent were ≥85 years.

The researchers calculated the adjusted hazard ratios (HRs) using Cox proportional hazards models with applied weights to examine the relationship between age and clinical outcomes. They also evaluated the comparative effectiveness of OAC versus no OAC and NOAC versus VKA using a propensity score with an overlap weighting scheme.

Compared with no OAC, treatment with OAC resulted in a nominal decrease in all-cause mortality among older adults aged 65‒74 years (HR, 0.86, 95 percent confidence interval [CI], 0.69‒1.06) and aged 75‒84 years (HR, 0.89, 95 percent CI, 0.75‒1.05), and a significant reduction in those aged ≥85 years (HR, 0.77, 95 percent CI, 0.63‒0.95). [Am J Med 2024;137:128-136.E13]

OAC use also contributed to a significant reduction in stroke among patients aged 65‒74 years (HR, 0.51, 95 percent CI, 0.35‒0.76) and ≥85 years (HR, 0.58, 95 percent CI, 0.34‒0.99) and a slight decrease among those aged 75‒84 years (HR, 0.84, 95 percent CI, 0.59‒1.18).

Notably, the incidence of major bleeding did not increase in patients aged ≥85 years who had been treated with OACs. Additionally, use of NOACs contributed to a substantial decrease in all-cause mortality in patients aged <65 and 65‒74 years, with nominal reductions in those aged 75‒84 and ≥85 years, as compared with VKAs.

“The results from this study would help inform the physician community in providing effective anticoagulation to older AF patients,” the researchers said.

“Despite these findings, it is likely that some healthcare providers continue to remain hesitant to prescribe anticoagulation to patients aged ≥75 [years] due to frailty, falling history, or comorbidities such as chronic kidney disease,” they added.

One strategy to solve this problem is to prescribe an ultra-low dose of OACs, such as edoxaban 15 mg daily (25 percent of the standard dose), according to the researchers. A Japanese placebo-controlled trial of patients aged ≥80 years reported an annualized rate of stroke or systemic embolism of 2.3 percent with edoxaban 15 mg versus 6.7 percent in the placebo group. [N Engl J Med 2020;383:1735-1745]

“In GARFIELD-AF, the highest-risk patients were most likely to receive nonrecommended low dose rather than recommended dose of NOACs,” the researchers said. “However, this approach warrants further study before it can be recommended.” [J Am Coll Cardiol 2020;76:1425-1436]