ACC: Newer anticoagulants may reduce medical costs compared with warfarin

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CHICAGO—The usage of dabigatran, rivaroxban and apixaban may be associated with a reduction in medical costs when used instead of warfarin—with apixaban “potentially” being associated with the greatest cost reduction, based on an analysis of ARISTOTLE, RE-LY and ROCKET-AF trials, presented March 26 at the 61st annual American College of Cardiology (ACC) scientific session.

Atrial fibrillation (AF) is the most common significant cardiac rhythm disorder, and is associated with a five-fold increased risk for ischemic stroke. The anticoagulant commonly used for stroke prevention in AF patients is warfarin, even though its therapeutic range is “narrow,” according to the study authors. In three large randomized, controlled trials—RE-LY, ROCKET-AF and ARISTOTLE—the novel oral anticoagulants dabigatran, rivaroxaban and apixaban demonstrated themselves as effective options for stroke prevention among nonvalvular AF patients.

Therefore, Steven B. Deitelzweig, MD, of Ochsner Clinic Foundation in New Orleans, and colleagues sought to evaluate the medical cost reductions associated with the use of individual novel oral anticoagulants instead of warfarin for stroke prevention in AF, from a U.S. payor perspective.

The researchers took the relative risks of clinical events, including ischemic stroke, hemorrhagic stroke, systemic embolism, MI, pulmonary embolism and deep vein thrombosis (DVT), associated with novel anticoagulants vs. warfarin from each trial publication. For warfarin, the rates of clinical events were estimated as the averages weighted by patient sample size in the three trials. The absolute risk of events, (i.e., the clinical event rate) associated with each novel oral anticoagulant, was derived by applying trial relative risks to the weighted averages of warfarin event rates. 

For the estimation of the medical costs, Deitelzweig et al obtained one-year incremental costs among AF patients with clinical events vs. those without events from the U.S. payor perspective from publications or based on input from clinical experts. The costs of clinical events were inflation adjusted to 2010 cost levels via the CPI Medical Care Index.

The authors noted that their “study focuses on the medical cost reduction driven by clinical outcomes, with drug costs and other additional monitoring-related expenses not included in this analysis.” 

For the incremental one-year costs of patients with clinical end points, these were the determined costs: ischemic or uncertain type of stroke ($39,511), hemorrhagic stroke ($51,659), systemic embolism ($19,756), MI ($37,446), pulmonary embolism or DVT ($19,756), major bleedings ($34,617), clinically relevant non-major bleedings ($522) and other minor bleeding ($97).

For these clinical events, the medical costs and cost differences per patient per year of novel anticoagulants in comparison with warfarin are as follows:
  • The warfarin costs for an ischemic or uncertain type of stroke is $490, and the cost differences with 150 mg dabigatran is $118 less, with rivaroxaban is $29 less and with apixaban is $39 less.
  • The warfarin costs for a hemorrhagic stroke is $225, and the cost differences with 150 mg dabigatran is $167 less, with rivaroxaban is $92 less and with apixaban is $110 less.
  • The warfarin costs for a systemic embolism is $27, and the cost differences with 150 mg dabigatran is $9 less, with rivaroxaban is $20 less and with apixaban is $3 less.
  • The warfarin costs for an MI is $292, and the cost differences with 150 mg dabigatran is $79 more, with rivaroxaban is $56 less and with apixaban is $35 less.
  • The warfarin costs for a pulmonary embolism or DVT is $13, and the cost differences with 150 mg dabigatran is $8 more, with rivaroxaban is $2 less and with apixaban is $3 less.
  • The warfarin costs for a major bleed (excluding hemorrhagic stroke) is $998, and the cost differences with 150 mg dabigatran is $31 more, with rivaroxaban is $108 more and with apixaban is $282 less.
  • The warfarin costs for a clinically relevant non-major bleed is $25, and the cost differences with 150 mg dabigatran is $2 less, with rivaroxaban is $1 more and with apixaban is $8 less.
  • The warfarin costs for other minor bleeds is $13, and the cost differences with 150 mg dabigatran is $1 less, with rivaroxaban is $2 more and with apixaban is $4 less.

Overall, the total costs for warfarin per patient per year are $2,084, and the cost differences with 150 mg dabigatran are $179 less, with rivaroxaban $89 less and with apixaban $485 less.

Therefore, Deitelzweig et al wrote that apixaban usage may potentially be associated with the greatest medical cost reduction, its cost reduction being primarily driven by significant reductions in the risks for both stroke and major bleeding events.

In acknowledging their study’s limitations, they wrote that drug costs and monitoring-related expenses as well as the long-term burden of clinical events, indirect costs and quality of life were not included in the analysis. Also, patient death was not included as an end point due to the substantial overlap between clinical events and deaths. Finally, they pointed out that their analysis was based on trial data, and therefore, might not have direct application of the results in the real-world setting.

However, the study authors said their results were consistent under additionally evaluated scenarios, when using median instead of mean incremental medical costs of AF patients with clinical events or when the clinical event rates of warfarin were taken separately from each original novel oral anticoagulant trial instead of estimated as the weighted average.

“The estimated medical cost reductions associated with novel oral anticoagulant usage, relative to warfarin, can be helpful in determining the overall cost impacts of the usage of novel oral anticoagulants for the growing population of AF patients in the U.S.,” the researchers concluded.