Apixaban linked to lesser adverse events in AF elderly patients with frailty: Study
USA: Apixaban compared with warfarin is associated with a lower rate of adverse events across all frailty levels in older adults with atrial fibrillation, the researchers report in Annals of Internal Medicine. Further, the researchers found dabigatran and rivaroxaban to be associated with lower events only among non-frail AF patients.
Currently, the decisions on anticoagulant therapy are driven mainly by risk assessment models for ischemic stroke and major bleeding without considering frailty. The role of frailty in the choice between a [direct oral anticoagulant] and warfarin is uncertain because of the poor representation of older adults with frailty and the lack of frailty assessment in clinical trials and anticoagulant use remains suboptimal in frail patients with AF.
Against the above background, Dae Hyun Kim, Hebrew SeniorLife, and Beth Israel Deaconess Medical Center, Boston, Massachusetts (D.H.K.), and colleagues aimed to examine the outcomes of direct oral anticoagulants (DOACs) versus warfarin by frailty levels.
For this purpose, the researchers conducted a 1:1 propensity score-matched analysis of Medicare data from 2010 to 2017 to compare outcome among three groups -- dabigatran users vs. warfarin users; rivaroxaban users vs. warfarin users, and apixaban users vs. warfarin users.
The researchers then measured the composite endpoint of death, ischemic stroke, or major bleeding by frailty levels, defined by a claims-based frailty index.
Key findings of the study include:
- In the dabigatran–warfarin cohort (n = 158 730; median follow-up, 72 days), the event rate per 1000 person-years was 63.5 for dabigatran initiators and 65.6 for warfarin initiators (hazard ratio [HR], 0.98).
- For nonfrail, prefrail, and frail persons, HRs were 0.81, 0.98, and 1.09, respectively.
- In the rivaroxaban–warfarin cohort (n = 275 944; median follow-up, 82 days), the event rate per 1000 person-years was 77.8 for rivaroxaban initiators and 83.7 for warfarin initiators (HR, 0.98).
- For nonfrail, prefrail, and frail persons, HRs were 0.88, 1.04, and 0.96, respectively.
- In the apixaban–warfarin cohort (n = 218 738; median follow-up, 84 days), the event rate per 1000 person-years was 60.1 for apixaban initiators and 92.3 for warfarin initiators (HR, 0.68).
- For nonfrail, prefrail, and frail persons, HRs were 0.61, 0.66, and 0.73, respectively.
"For older adults with AF, apixaban was associated with lower rates of adverse events across all frailty levels," wrote the authors. "Dabigatran and rivaroxaban were associated with lower event rates only among nonfrail patients."
The study titled, "Frailty and Clinical Outcomes of Direct Oral Anticoagulants Versus Warfarin in Older Adults With Atrial Fibrillation," is published in Annals of Internal Medicine.