麻豆传媒

Although older people with atrial fibrillation (Afib) were increasingly willing to initiate and adhere to their prescribed anticoagulants in recent years, this population stayed undertreated as a whole as recently as 2020, a study found.

Within those on a Medicare Advantage plan, the proportion of Afib patients filling a prescription for an oral anticoagulant (OAC) within 12 months of diagnosis improved significantly from 20.2% in 2010 to 32.9% in 2020, attributed in part to the advent of direct oral anticoagulants (DOACs) during this period, according to Dae Hyun Kim, MD, ScD, of Hebrew SeniorLife and Beth Israel Deaconess Medical Center in Boston, and colleagues.

Increases in OAC initiation and DOAC uptake were similar across subgroups by race and ethnicity, bleeding risk, and prior stroke. However, factors associated with low OAC initiation were older age, dementia, frailty, and anemia, Kim's group reported in .

"The association between noninitiation of OAC in older adults with concomitant geriatric conditions highlights the frequent challenges faced by clinicians in optimizing the risks and benefits of OAC in a medically complex older population," the authors wrote.

"Several factor XIa inhibitors are currently undergoing phase 2 trials, and if proven to reduce bleeding risks compared with factor Xa inhibitors, this new class of anticoagulants may address this large unmet clinical need," the team suggested.

Indeed, fears of life-threatening bleeding, even with the use of reversal agents, are not eliminated with apixaban (Eliquis), the factor Xa inhibitor that contributed most to rising OAC use up to 2020 in the report by Kim and colleagues.

Apixaban, FDA approved in 2012 for people with Afib, is particularly appealing among the DOACs because of its relatively low bleeding risk, more predictable pharmacokinetics, and association with lower composite clinical events. It had been hoped that DOACs would generally improve OAC utilization in Afib given a superior safety profile and relative ease of use compared with warfarin and its required international normalised ratio (INR) tests.

To a certain extent, that has been true. Besides the evidence of in older people, the Medicare Advantage population also cut nonadherence to OACs from 52.2% to 39.0% since DOACs became available, Kim's team reported.

Whether these findings can be generalized to older adults overall is unknown, however, as fewer than half of Medicare-eligible people opt for Medicare Advantage. The analysis was also restricted to patients who survived and kept their insurance coverage for the entire calendar year of their diagnosis, the study authors noted.

"One surprising finding was the low overall use of anticoagulants in this sample" when the "general trends of increasing anticoagulation use over time seemed consistent," commented Margaret Fang, MD, medical director of the University of California San Francisco Anticoagulation Clinic, who was not involved with the study.

She suggested to 麻豆传媒 that some Afib diagnoses could have been considered clinically insignificant to prescribers yet still counted in the present analysis.

"It would be interesting to see what has happened to anticoagulant use since the pandemic," Fang added. "The fears of COVID-19 could accelerate even further the transition from warfarin to DOACs, since patients may want to minimize exposure to healthcare settings, such as for INR checks."

For their retrospective cohort study, Kim and colleagues analyzed administration claims from Optum's Clinformatics Data Mart. The study population was limited to beneficiaries of Medicare Advantage plans age 65 years and older with Afib and elevated risk of ischemic stroke who had no contraindications to DOACs or warfarin.

The cohort came out to over 380,000 eligible people (mean age 77 years, roughly split between the sexes). About 8% had had a prior stroke or transient ischemic attack. Average CHA2DS2-VASc and HAS-BLED scores were 4.5 and 3.8, respectively.

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