Clinical and Economic Implications of Apixaban Versus Aspirin in the Low-Risk Nonvalvular Atrial Fibrillation Patients

Abstract

Background and Purpose-Although recommended by guidelines, the benefits of treating patients with atrial fibrillation with a low-stroke risk score, with aspirin or anticoagulants, have not been clearly established. With advent of safer nonvitamin K antagonist oral anticoagulant, we assessed the clinical and economic implications of 5 mg BID of apixaban versus aspirin among patients with a relative low risk of stroke as assessed using the CHADS 2 (congestive heart failure, hypertension, age>75, diabetes mellitus, stroke/transient ischemic attack) and CHA 2 DS 2 -VASc (congestive heart failure, hypertension, age, diabetes mellitus, stroke/transient ischemic attack, vascular disease) stroke risk classification. Methods-A previously developed and validated Markov model was adapted. A secondary analysis of the Apixaban VersusAcetylsalicylic Acid to Prevent Stroke in Atrial Fibrillation Patients Who Have Failed or Are Unsuitable for Vitamin K Antagonist Treatment (AVERROES) study was conducted to estimate event rates in different low-risk cohorts by treatment. Three cohorts (n=1000) with a CHADS 2 score of 1, CHA 2 DS 2 -VASc score of 1, and CHA 2 DS 2 -VASc of score 2 to 4 were simulated to assess the number of clinical events avoided in terms of strokes and major bleeds, as well as life years gained, quality-adjusted life years gained, costs, and incremental costs per quality-adjusted life year gained. Results-Apixaban was associated with fewer strokes and systemic embolism versus aspirin across all subgroups; however, it caused more major bleeding events. The reduction in systemic embolism offset the increase in major bleeding events leading to increased life expectancy and quality-adjusted life year gains, achieved at an increased cost that was lower than the UK threshold of $44 400 (ie, £30 000) per quality-adjusted life year gained across the 3 cohorts examined. Conclusions-Anticoagulant treatment with apixaban versus aspirin in low-risk patients, as identified using CHADS 2 or CHA 2 DS 2 -VASc, is projected to increase life expectancy and provide clinical benefits that are cost effective.

Cost-effectiveness of Direct Oral Anticoagulant vs. Warfarin Among Atrial Fibrillation Patients With Intermediate Stroke Risk

“…There is little evidence in previous literature on the cost-effectiveness of DOACs in AF patients with intermediate stroke risk, and only a few investigated the cost-effectiveness of DOACs compared with warfarin while considering stroke risk ( 9 , 17 , 18 ). A UK study, which included 1,000 AF patients, showed that apixaban was more cost-effective than aspirin among AF patients with intermediate stroke risk, both having an ICER of $26,852 for a CHADS score of 1 and $14,001 for a CHA 2 DS 2 -VASc score of 1, respectively ( 17 ). However, our study included 7,954 AF patients with intermediate stroke risk, and the ICER of apixaban was $8,426.71 per QALY.…”

“…However, this reimbursement scheme is limited to AF patients with high stroke risk (defined as a CHA 2 DS 2 -VASc score of 2 or higher), as most previous studies on the cost-effectiveness of DOACs included AF patients with high stroke risk or did not consider the risk of stroke ( 16 ). Some studies have investigated the cost-effectiveness of DOACs after a stratification on individuals regarding stroke risk ( 9 , 17 , 18 ). To the best of our knowledge, no purposely designed study has investigated the cost-effectiveness of DOACs by focusing on the intermediate stroke risk group.…”

A Cost-Effectiveness Analysis of Biomarkers for Risk Prediction in Atrial Fibrillation

“…The baseline estimates of the annual clinical event rates for the SOC strategy (Table 1 ) were obtained from the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial [ 19 ]. Those for the PM strategy, low and intermediate-untreated risk groups (Tables 2 , 3 ) were obtained from published studies in low-risk and/or untreated or non-anticoagulated patients [ 24 , 25 ]. The clinical event rates for the intermediate-treated and high-risk groups (Tables 4 , 5 ) were obtained from the ABC-Stroke [ 17 ] and ABC-Bleeding [ 16 ] risk score data, except for ischemic and hemorrhagic stroke, MI, and death, which were derived from the hs-TnI substudy [ 26 ].…”