Cost-Effectiveness and Budget Impact Analysis of Apixaban and Rivaroxaban Versus Warfarin in the Prevention of Stroke in Patients With Non-Valvular Atrial Fibrillation (NVAF) in Iran.

INTRODUCTION: This study evaluates the cost-effectiveness of Apixaban and Rivaroxaban, compared to Warfarin, for stroke prevention in patients with non-valvular atrial fibrillation in Iran. METHOD: A Markov model with a 30-year time horizon was employed to simulate and assess different treatment strategies' cost-effectiveness. The study population comprised Iranian adults with NVAF, identified through specialist consultations, hospital visits, and archival record reviews. Direct medical costs, direct nonmedical, and indirect costs were included. Quality-adjusted life years (QALY) were assessed using an EQ-5D questionnaire. This study utilized a cost-effectiveness threshold of $11 134 per QALY. RESULTS: Apixaban demonstrated superior cost-effectiveness compared to Rivaroxaban and Warfarin. Over 30 years, total costs were lower in the Apixaban and Rivaroxaban groups compared to the Warfarin group ($126.18 and $109.99 vs. $150.49). However, Apixaban showed higher total QALYs gained compared to others (0.134 vs. 0.133 and 0.116). The incremental cost-effectiveness ratio for comparing Apixaban to Warfarin was calculated at -1332.83 cost per QALY, below the threshold of $11 134, indicating Apixaban's cost-effectiveness. Sensitivity analyses confirmed the robustness of the findings, with ICER consistently remaining below the threshold. Over 5 years (2024-2028) of Apixaban usage, the incremental cost starts at USD 70 250 296 in the first year and gradually rises to USD 71 770 662 in the fifth year. DSA and PSA were assessed to prove the robustness of the results. CONCLUSION: This study shows that Apixaban is a cost-effective option for stroke prevention in non-valvular atrial fibrillation patients in Iran compared to Warfarin.

Comparative Safety and Effectiveness of Warfarin or Rivaroxaban Versus Apixaban in Patients With Advanced CKD and Atrial Fibrillation: Nationwide US Cohort Study.

RATIONALE & OBJECTIVE: Head-to-head data comparing the effectiveness and safety of oral anticoagulants in patients with atrial fibrillation (AF) and advanced chronic kidney disease (CKD) are lacking. We compared the safety and effectiveness of warfarin or rivaroxaban versus apixaban in patients with AF and non-dialysis-dependent CKD stage 4/5. STUDY DESIGN: Propensity score-matched cohort study. SETTING & PARTICIPANTS: 2 nationwide US claims databases, Medicare and Optum's deidentified Clinformatics Data Mart Database, were searched for the interval from January 1, 2013, through March 31, 2022, for patients with nonvalvular AF and CKD stage 4/5 who initiated warfarin versus apixaban (matched cohort, n=12,488) and rivaroxaban versus apixaban (matched cohort, n = 5,720). EXPOSURES: Warfarin, rivaroxaban, or apixaban. OUTCOMES: Primary outcomes included major bleeding and ischemic stroke. Secondary outcomes included all-cause mortality, major gastrointestinal bleeding, and intracranial bleeding. ANALYTICAL APPROACH: Cox regression was used to estimate HRs, and 1:1 propensity-score matching was used to adjust for 80 potential confounders. RESULTS: Compared with apixaban, warfarin initiation was associated with a higher rate of major bleeding (HR, 1.85; 95% CI, 1.59-2.15), including major gastrointestinal bleeding (1.86; 1.53-2.25) and intracranial bleeding (2.15; 1.42-3.25). Compared with apixaban, rivaroxaban was also associated with a higher rate of major bleeding (1.69; 1.33-2.15). All-cause mortality was similar for warfarin (1.08; 0.98-1.18) and rivaroxaban (0.94; 0.81-1.10) versus apixaban. Furthermore, no statistically significant differences for ischemic stroke were observed for warfarin (1.14; 0.83-1.57) or rivaroxaban (0.71; 0.40-1.24) versus apixaban, but the CIs were wide. Similar results were observed for warfarin versus apixaban in the positive control cohort of patients with CKD stage 3, consistent with randomized trial findings. LIMITATIONS: Few ischemic stroke events, potential residual confounding. CONCLUSIONS: In patients with AF and advanced CKD, rivaroxaban and warfarin were associated with higher rates of major bleeding compared with apixaban, suggesting a superior safety profile for apixaban in this high-risk population. PLAIN-LANGUAGE SUMMARY: Different anticoagulants have been shown to reduce the risk of stroke in patients with atrial fibrillation, such as warfarin and direct oral anticoagulants like apixaban and rivaroxaban. Unfortunately, the large-scale randomized trials that compared direct anticoagulants versus warfarin excluded patients with advanced chronic kidney disease. Therefore, the comparative safety and effectiveness of warfarin, apixaban, and rivaroxaban are uncertain in this population. In this study, we used administrative claims data from the United States to answer this question. We found that warfarin and rivaroxaban were associated with increased risks of major bleeding compared with apixaban. There were few stroke events, with no major differences among the 3 drugs in the risk of stroke. In conclusion, this study suggests that apixaban has a better safety profile than warfarin and rivaroxaban.

Payer formulary tier increases of apixaban: how patients respond and potential implications.

OBJECTIVE: To assess potential impacts of formulary tier increases of apixaban-an efficacious oral anticoagulant (OAC) for preventing stroke in patients with atrial fibrillation (AF)-on patients' prescription drug plan (PDP) switching and OAC treatment patterns. METHODS: Nationwide claims data for Medicare beneficiaries with Parts A, B, and D (100% sample) were used to assess apixaban-treated AF patients who faced a formulary tier increase for apixaban in 2017 by their Part D PDP. Patients' out-of-pocket (OOP) costs for apixaban were described, along with PDP switching and OAC treatment patterns. RESULTS: Among 1845 included patients, 97.7% had apixaban on tier 3 of their plan's formulary in 2016 and faced its increase to tier 4 for 2017. Approximately 4% (N = 81) of patients pre-emptively switched to a different PDP for 2017 with almost all switching to plans with apixaban on a lower formulary tier and 85.2% continuing apixaban treatment. Among the 96% (N = 1764) of patients who remained on the same PDP for 2017, over half (57.5%) continued apixaban treatment, despite increased OOP costs ($54 vs. $135 for a 30-day supply in 2016 vs. 2017). Only 12.4% of those who remained on the same plan for 2017 switched to another OAC, while as much as 30.1% discontinued OACs. These discontinuers exhibited higher comorbidity burdens than patients continuing on any OAC. CONCLUSION: The majority of patients continued on apixaban despite higher OOP cost, suggesting patients' reluctance to change treatment for non-medical reasons; however, 30% of patients discontinued OAC treatment after higher apixaban tier placement.

Healthcare resources and costs associated with nonvalvular atrial fibrillation in Spain: apixaban versus acenocoumarol.

Aim: Healthcare resources usage and costs associated to nonvalvular atrial fibrillation (NVAF) were analyzed in Spain. Methods: This is an observational and retrospective study on patients with NVAF who started their treatment with apixaban or acenocoumarol between 1 January 2015 and 31 December 2017. Results: 2160 patients treated with apixaban were paired (1:1) with patients treated with acenocoumarol (propensity score matching). Apixaban reduced the incidence of strokes and systemic embolisms, minor and major bleedings and deaths, versus acenocoumarol. Apixaban led to reductions of 80, 55 and 43% in costs related to nursing visits, hospitalizations, and emergency visits, respectively, leading to annual cost savings of €274/patient, from the perspective of society. Conclusion: Our results suggested that apixaban is a cost-effective alternative for patients with NVAF.

Cost-effectiveness of targeted screening for non-valvular atrial fibrillation in the United Kingdom in older patients using digital approaches.

AIM: Screening for non-valvular atrial fibrillation (NVAF) is key in identifying patients with undiagnosed disease who may be eligible for anticoagulation therapy. Understanding the economic value of screening is necessary to assess optimal strategies for payers and healthcare systems. We evaluated the cost effectiveness of opportunistic screening with handheld digital devices and pulse palpation, as well as targeted screening predictive algorithms for UK patients ≥75 years of age. METHODS: A previously developed Markov cohort model was adapted to evaluate clinical and economic outcomes of opportunistic screening including pulse palpation, Zenicor (extended 14 days), KardiaMobile (extended), and two algorithms compared to no screening. Key model inputs including epidemiology estimates, screening effectiveness, and risks for medical events were derived from the STROKESTOP, ARISTOTLE studies, and published literature, and cost inputs were obtained from a UK national cost database. Health and cost outcomes, annually discounted at 3.5%, were reported for a cohort of 10,000 patients vs. no screening over a time horizon equivalent to a patient's lifetime, Analyses were performed from a UK National Health Services and personal social services perspective. RESULTS: Zenicor, pulse palpation, and KardiaMobile were dominant (providing better health outcomes at lower costs) vs. no screening; both algorithms were cost-effective vs. no screening, with incremental cost-effectiveness ratios per quality-adjusted life-year (QALY) of £1,040 and £1,166. Zenicor, pulse palpation, and KardiaMobile remained dominant options vs. no screening in all scenarios explored. Deterministic sensitivity analyses indicated long-term stroke care costs, prevalence of undiagnosed NVAF in patients 75-79 years of age, and clinical efficacy of anticoagulant on stroke prevention were the main drivers of the cost-effectiveness results. CONCLUSIONS: Screening for NVAF at ≥75 years of age could result in fewer NVAF-related strokes. NVAF screening is cost-effective and may be cost-saving depending on the program chosen.

Apixaban versus other anticoagulants in patients with nonvalvular fibrillation: a comparison of all-cause and event-related costs in real-life setting in France.

OBJECTIVES: Compare costs associated with all-cause healthcare resource use (HCRU), stroke/systemic thromboembolism (STE) and major bleedings (MB) between patients with non-valvular atrial fibrillation (NVAF) initiating apixaban or other oral anticoagulants (OACs). METHODS: We performed a retrospective cohort study using the French healthcare claims database, including NVAF patients between 2014/01/01 and 2016/12/31, followed until 2016/12/31. We used 4 sub-cohorts of OAC-naive patients, respectively initiating apixaban, dabigatran, rivaroxaban or VKAs. We matched patients initiating apixaban with patients initiating each other OACs using 1:n propensity score matching. All-cause HCRU and event-related costs by OAC treatment were estimated and compared between matched patients using generalised-linear models with gamma-distribution and two-part models. RESULTS: There were 175,766 patients in the apixaban-VKA, 181,809 in the apixaban-rivaroxaban, and 42,490 in the apixaban-dabigatran matched cohorts. Patients initiating apixaban had significantly lower HCRU costs than patients initiating VKA (€1,105 vs. €1,578, p < 0.0001), dabigatran (€993 vs. €1,140, p < 0.0001) and rivaroxaban (€1,013 vs. €1,088 p < 0.0001). They have had significantly lower costs related to stroke/STE and MB than patients initiating VKA (respectively, €183 vs. €449 and €147 vs. €413; p < 0.0001), rivaroxaban (respectively, €145 vs. €197 and €129 vs. €193; p < 0.0001), and lower costs related to stroke/STE than patients initiating dabigatran (€135 vs. €192, p < 0.02). Costs related to MB were not significantly different in patients initiating apixaban and those initiating dabigatran (€119 vs. €149, p = 0.07). CONCLUSIONS: HCRU and most event-related costs were lower in patients initiating apixaban compared to other OACs. Apixaban may be cost-saving compared to VKAs, and significantly cheaper than other DOACs, although cost differences are limited.

Payer formulary exclusions of apixaban: how patients respond and potential implications.

In recent years, US payers have increased usage of formulary exclusions as a means to help manage costs. Earlier this year, one of the largest pharmacy benefit managers in the country added Eliquis (apixaban), the most widely used anticoagulant, to its list of excluded medicines from its formulary, raising concerns by physicians and patients. In this commentary, we examine the potential impacts of formulary exclusion of a drug like apixaban-a treatment for patients with atrial fibrillation and venous thromboembolism to help prevent stroke and clotting events and which has been demonstrated to have a strong efficacy and safety profile. We discuss the effect of formulary exclusions on patients' ability to access the most clinically appropriate treatment for their health needs, along with possible effects on their health and well-being. We also report descriptive results on apixaban-treated patients with traditional Medicare coverage who faced a formulary exclusion of apixaban in 2017, and these patients' observed behaviors. We found that the majority of these patients remained on apixaban either through pre-emptively switching to a different Part D drug plan with apixaban coverage or applying for formulary exception. Our findings suggest that formulary exclusion did not help to achieve the goal of switching patients to less costly medications but created additional hurdles for patients to access their preferred treatment and increased patient burden. Alternative ways to manage payer costs may be needed to help avoid poor outcomes and reduce the burden placed on patients in their efforts to access life-saving medications.

Impact of comparative effectiveness research on Medicare coverage of direct oral anticoagulants.

Aim: To evaluate the association of comparative effectiveness research with Medicare coverage of direct oral anticoagulants. Materials & methods: A literature review for direct oral anticoagulants was conducted from 2011 to 2017. Monthly prescription drug plan and formulary files (n = 28) were used to conduct change-point analysis and assess each outcome variable. Results: Up to 2013, studies showed that dabigatran was more effective than rivaroxaban. In 2015, apixaban was shown to be the safest and most effective drug in comparison with all direct oral anticoagulants. In 2016-2017, dabigatran and apixaban were shown to have similar efficacy. Approximately 75% of plans covered dabigatran under tier 3 until 2015. From 2011 to 2017, less than 30% of plans required prior authorizations, 50% imposed quantity limits and mean copayment was lowest for rivaroxaban. Conclusion: Consistent with comparative effectiveness research, Medicare plans covered apixaban more favorably and edoxaban less favorably. However, discrepancies in comparative effectiveness research translation were found for rivaroxaban and dabigatran.

Direct Oral Anticoagulants Versus Warfarin in Patients With Atrial Fibrillation and Valve Replacement or Repair.

Background We sought to examine outcomes of direct oral anticoagulants (DOACs) versus warfarin in atrial fibrillation with valve repair/replacement. Methods and Results Two atrial fibrillation cohorts from Medicare were identified from 2015 to 2019. They comprised patients who underwent surgical or transcatheter mitral valve repair (MV repair cohort) and surgical aortic or mitral bioprosthetic or transcatheter aortic valve replacement (bioprosthetic cohort). Each cohort was divided into warfarin and DOACs (apixaban, rivaroxaban, and dabigatran) groups. Study outcomes included mortality, stroke, and major bleeding. Inverse probability weighting was used for adjustment between the 2 groups in each cohort. The MV repair cohort included 1178 patients. After a median of 468 days, DOACs were associated with lower risk of mortality (hazard ratio [HR], 0.67 [95% CI, 0.55-0.82], P<0.001), ischemic stroke (HR, 0.72 [95% CI, 0.52-1.00], P=0.05) and bleeding (HR, 0.79 [95% CI, 0.63-0.99], P=0.04) compared with warfarin. The bioprosthetic cohort included 8089 patients. After a median follow-up of 413 days, DOACs were associated with similar risk of mortality (adjusted HR, 0.93 [95% CI, 0.86-1.01], P=0.08), higher risk of ischemic stroke (adjusted HR, 1.27 [95% CI, 1.13-1.43], P<0.001), and lower risk of bleeding (adjusted HR, 0.86 [95% CI, 0.80-0.93], P<0.001) compared with warfarin. Conclusions In patients with atrial fibrillation, DOACs are associated with similar mortality, lower bleeding, but higher stroke with bioprosthetic valve replacement and lower risk of all 3 outcomes with MV repair compared with warfarin.

Cost-effectiveness of direct oral anticoagulants compared to low-molecular-weight-heparins for treatment of cancer associated venous thromboembolism in Spain.

AIM: Recent studies have compared the efficacy and safety of direct-acting oral anticoagulants (DOAC) and low-molecular-weight heparin (LMWH) for cancer-associated venous thromboembolism (VTE). However, there is no available cost-effectiveness analysis comparing DOAC and LMWH. The study aimed to conduct a cost-effectiveness analysis of DOAC (apixaban, edoxaban, and rivaroxaban) vs. LMWH for the treatment of cancer-associated VTE in Spain from the Spanish healthcare system perspective. METHODS: We developed a Markov model with a 12-month time horizon. The states included pulmonary embolism, deep vein thrombosis, major and non-major bleeding, chronic thromboembolic pulmonary hypertension, post-thrombotic syndrome, and death. The use of medical resources and drug costs were obtained from the 2021 Spanish Ministry of Health database, and the main references for obtaining the outcomes were derived from Caravaggio, Hokusai VTE Cancer, ADAM VTE, and SELECT-D trials. We performed a deterministic and probabilistic sensitivity analysis to validate the robustness. The Incremental Cost-Effectiveness Ratio (ICER) scores cost per life-year (€/LY) gained and cost per quality-adjusted life-year (€/QALY) gained. RESULTS: The 12-month cost of DOAC was 1,994€ (apixaban 1,944€, edoxaban 1,968€, rivaroxaban 2,122€) and 2,152€ for LMWH. The amount of QALY for DOAC was 0.54 (apixaban 0.55, rivaroxaban 0.53, and edoxaban 0.52) and 0.53 for LMWH. We observed similar results for LYs. ICER scores in terms both of €/LY and €/QALY show that DOAC is dominant over LMWH and apixaban showed the best profile. LIMITATIONS: Our research is based on an indirect comparison of a short-term clinical trial. CONCLUSION: Our results suggest that DOAC is cost-effective and cost-saving compared to LMWH in treating VTE.

Thromboprophylaxis of Patients Submitted to Total Hip and Knee Arthroplasty: A Cost-Effectiveness Assessment From the Perspective of the Brazilian National Health System.

OBJECTIVES: Venous thromboembolism (VTE) is a serious national and international public health issue. Major orthopedic surgeries, such as a total hip (THA) and knee (TKA) arthroplasties, are associated with an increased risk of VTE, long-term complications, functional disability, and death resulting from hypercoagulability by surgical trauma. This pharmacoeconomic analysis aimed to identify the most cost-effective anticoagulant alternative in preventing VTE in patients undergoing THA and TKA. METHODS: A decision tree model was developed, comparing direct oral anticoagulants (rivaroxaban, apixaban, and dabigatran) with enoxaparin, with separate THA and TKA models a 3-month time horizon from the perspective of the Brazilian National Health System. The results were presented as incremental cost-effectiveness ratio (ICER), and the outcomes analyzed were avoided complications (ACs) after thromboprophylaxis. Comparative effectiveness was obtained from a published meta-analysis. A willingness to pay value of approximately R$ 15 000.00 was used per AC, and a probabilistic sensitivity analysis with the Monte Carlo simulation was conducted. RESULTS: Apixaban was the anticoagulant that presented the best ICER for patients undergoing THA (R$ 207.52/AC) and TKA (R$ 133.59/AC), followed by rivaroxaban (R$ 347.21/AC), dabigatran (R$ 372.56/AC), and enoxaparin (R$ 711.44/AC) for THA and by dabigatran (R$ 194.07/AC), rivaroxaban (R$ 221.12/AC), and enoxaparin (R$ 747.25/AC) for TKA. After ICER analysis, apixaban prevails over the other technologies analyzed for both surgical procedures, confirmed after sensitivity analysis. CONCLUSION: Our model suggests that, in the Brazilian National Health System, apixaban is the most cost-effective alternative in preventing VTE after THA and TKA.

Apixaban Dosing Patterns Versus Warfarin in Patients With Nonvalvular Atrial Fibrillation Receiving Dialysis: A Retrospective Cohort Study.

BACKGROUND & OBJECTIVES: Comparison of clinical outcomes across anticoagulation regimens using different apixaban dosing or warfarin is not well-defined in patients with nonvalvular atrial fibrillation (AF) who are receiving dialysis. This study compared these outcomes in a US national cohort of patients with kidney failure receiving maintenance dialysis. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Patients receiving dialysis represented in the US Renal Data System database 2013-2018 who had AF and were treated with apixaban or warfarin. EXPOSURE: First prescribed treatment with apixaban dosed according to the label, apixaban dosed below the label, or warfarin. OUTCOME: Ischemic stroke/systemic embolism, major bleeding, and all-cause mortality. ANALYTICAL APPROACH: Cox proportional hazards models with inverse probability of treatment weighting. Analyses simulating an intention-to-treat (ITT) approach as well as those incorporating censoring at drug switch or discontinuation (CAS) were also implemented. Inverse probability of censoring weighting was used to account for possible informative censoring. RESULTS: Among 17,156 individuals, there was no difference in risk of stroke/systemic embolism among the label-concordant apixaban, below-label apixaban, and warfarin treatment groups. Both label-concordant (HR, 0.67 [95% CI, 0.55-0.81]) and below-label (HR, 0.68 [95% CI, 0.55-0.84]) apixaban dosing were associated with a lower risk of major bleeding compared with warfarin in ITT analyses. Compared with label-concordant apixaban, below-label apixaban was not associated with a lower bleeding risk (HR, 1.02 [95% CI, 0.78-1.34]). In the ITT analysis of mortality, label-concordant apixaban dosing was associated with a lower risk versus warfarin (HR, 0.85 [95% CI, 0.78-0.92]) while there was no significant difference in mortality between below-label dosing of apixaban and warfarin (HR, 0.97 [95% CI, 0.89-1.05]). Overall, results were similar for the CAS analyses. LIMITATIONS: Study limited to US Medicare beneficiaries; reliance on administrative claims to ascertain outcomes of AF, stroke, and bleeding; likely residual confounding. CONCLUSIONS: Among patients with nonvalvular AF undergoing dialysis, warfarin is associated with an increased risk of bleeding compared with apixaban. The risk of bleeding with below-label apixaban was not detectably less than with label-concordant dosing. Label-concordant apixaban dosing is associated with a mortality benefit compared to warfarin. Label-concordant dosing, rather than reduced-label dosing, may offer the most favorable benefit-risk trade-off for dialysis patients with nonvalvular AF.

Apixaban versus Warfarin for Treatment of Venous Thromboembolism in Patients Receiving Long-Term Dialysis.

BACKGROUND AND OBJECTIVES: The association of apixaban compared with warfarin for the treatment of venous thromboembolism in patients receiving maintenance dialysis is not well studied. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted a retrospective cohort study of Medicare fee-for-service beneficiaries receiving dialysis using United States Renal Data System data from 2013 to 2018. The study included patients who received a new prescription for apixaban or warfarin following a venous thromboembolism diagnosis. The outcomes were recurrent venous thromboembolism, major bleeding, and death. Outcomes were analyzed using Cox proportional hazards regression for intention-to-treat and censored-at-drug-switch-or-discontinuation analyses. Models incorporated inverse probability of treatment and censoring weights to minimize confounding and informative censoring. RESULTS: In 12,206 individuals, apixaban, compared with warfarin, was associated with lower risks of both recurrent venous thromboembolism (hazard ratio [HR], 0.58; 95% confidence interval [95% CI], 0.43 to 0.77) and major bleeding (HR, 0.78; 95% CI, 0.62 to 0.98) in the intention-to-treat analysis over 6 months of follow-up. However, there was no difference between apixaban and warfarin in terms of risk of all-cause death (HR, 1.04; 95% CI, 0.94 to 1.16). Corresponding hazard ratios for the 6-month censored-at-drug-switch-or-discontinuation analysis and for corresponding analyses limited to a shorter (3-month) follow-up were all highly similar to the primary analysis. CONCLUSIONS: In a large group of US patients on dialysis with recent venous thromboembolism, we observed that apixaban was associated with lower risk of recurrent venous thromboembolism and of major bleeding than warfarin. There was no observed difference in mortality.

Assessment of Anti-Xa activity in patients receiving concomitant apixaban with strong p-glycoprotein inhibitors and statins.

WHAT IS KNOWN AND OBJECTIVES: Although the apixaban Food and Drug Administration (FDA) package insert recommends dose reduction in patients administered dual strong inhibitors of p-glycoprotein (P-gp) and cytochrome P-450 (CYP) 3A4, there are limited published data regarding potential drug-drug interactions between apixaban (Eliquis) and common p-glycoprotein (P-gp) and CYP3A4 inhibitors co-administered with statins. The aim of this study was to investigate the degree of elevation relative to apixaban serum peak and trough concentration after the co-administration of amiodarone, diltiazem and statins (atorvastatin, rosuvastatin and simvastatin). METHODS: Patients prescribed apixaban 5mg twice daily for at least one week were identified from the anticoagulation clinic database and contacted for potential enrolment. A total of 117 volunteers were enrolled with eight excluded due to discontinued use, resulting in 109 volunteers (44 females and 65 males delineated into age groups 40-64 and ≥65 years old) completing the observational study. Fifty-five volunteers were administered apixaban without the P-gp inhibitors amiodarone or diltiazem, with or without statins (atorvastatin, rosuvastatin and simvastatin). Fifty-four volunteers were administered apixaban with either amiodarone or diltiazem, with or without statins (atorvastatin, rosuvastatin or simvastatin). Peak and trough concentrations were assessed for each patient utilizing an apixaban anti-Xa assay. RESULTS: Of the combinations studied, the mean apixaban trough concentration upon co-administration of amiodarone without a statin was elevated compared to apixaban alone (experimental 156.83 +/- 79.59 ng/ml vs. control 104.09 +/- 44.56 ng/ml; p = 0.04). The co-administration of diltiazem and rosuvastatin, and the administration of amiodarone without a statin led to greater than 1.5-fold increase in apixaban concentrations (peak experimental 315.19 +/- 157.53 ng/ml vs control 207.6 +/- 83.38 ng/ml; p = 0.08 and trough experimental 182.03 +/- 95.93 ng/ml vs control 112.32 +/- 37.78 ng/ml; p = 0.17) suggesting the need to assess dose adjustment for patients per the FDA package insert. In addition, the aggregated mean peak (p = 0.0056) and trough (p = 0.0089) elevation of CYP3A4 experimental groups (atorvastatin and simvastatin) co-administered apixaban and diltiazem were statistically significant compared with the aggregated non-CYP3A4 control groups (no statin and rosuvastatin). WHAT IS NEW AND CONCLUSION: Herein, we report novel data regarding peak and trough apixaban concentrations after concomitant administration of P-gp and CYP3A4 inhibitors (amiodarone or diltiazem) co-administered with statins (atorvastatin, rosuvastatin or simvastatin). Providers should consider utilizing the apixaban anti-Xa assay or comparative heparin anti-Xa assay to determine if patients require dose reduction to decrease adverse events in high-risk patients prescribed apixaban and concomitant p-glycoprotein and CYP3A4 inhibitors amiodarone or diltiazem with and without a CYP3A4 or non-3A4 statin.

Effectiveness and Safety of Apixaban Versus Warfarin Among Older Patients with Venous Thromboembolism with Different Demographics and Socioeconomic Status.

INTRODUCTION: Impact of demographics and socioeconomic status (SES) on anticoagulant treatment outcomes among patients with venous thromboembolism (VTE) is not well understood. This study evaluated risks of recurrent VTE, major bleeding (MB), and clinically relevant non-major bleeding (CRNMB) among older patients with VTE initiating apixaban or warfarin stratified by demographics and SES. METHODS: Adult patients (≥ 65 years) who initiated apixaban or warfarin after a VTE event were selected from the US CMS Medicare database (September 2014-December 2017). Stabilized inverse probability treatment weighting (IPTW) was used to balance patient characteristics between treatment cohorts. Patients were stratified by age, gender, race, and SES. For each subgroup, Cox proportional hazard models were used to evaluate if there was a significant interaction (p < 0.10) between treatment and subgroup for recurrent VTE, MB, and CRNMB. RESULTS: In total, 22,135 apixaban and 45,840 warfarin patients with VTE were included. Post-IPTW, patient characteristics were balanced between treatment cohorts. In older patients, apixaban treatment was associated with significantly lower risks of recurrent VTE (hazard ratio [HR] 0.64; 95% confidence interval [CI] 0.52-0.79), MB (HR 0.65; 95% CI 0.57-0.75), and CRNMB (HR 0.79; 95% CI 0.75-0.85) versus warfarin. When stratified by demographics and SES, higher incidence rates of recurrent VTE, MB, and CRNMB were observed for black vs white patients and patients with lower vs higher SES. Comparison of apixaban with warfarin by different demographic and SES subgroups showed generally consistent results as the overall analysis. For most subgroups, no significant interaction was observed between treatment and subgroup strata for recurrent VTE, MB, and CRNMB. CONCLUSION: Among older patients with VTE initiating apixaban or warfarin, higher rates of recurrent VTE and bleeding were observed in black patients and patients with lower SES. Apixaban had a lower risk of recurrent VTE, MB, and CRNMB compared to warfarin. Analyses of demographic and SES subgroups showed consistent findings.

Cost-Effectiveness of Apixaban versus Other Direct Oral Anticoagulants and Warfarin in the Prevention of Thromboembolic Complications Among Finnish Patients with Non-Valvular Atrial Fibrillation.

PURPOSE: Direct oral anticoagulant (DOAC) use for the prevention of thromboembolic complications in patients with non-valvular atrial fibrillation (AF) has increased steadily in Finland. DOACs have been shown to be cost-effective in comparison to warfarin, but published evidence of relative cost-effectiveness between DOACs is still scarce and mostly based on indirect comparisons of clinical trial evidence. The aim of this study was to compare the cost-effectiveness of apixaban to dabigatran, rivaroxaban and warfarin in a Finnish setting using real-life evidence where available. PATIENTS AND METHODS: A lifetime Markov simulation model used previously in a published Finnish assessment comparing apixaban and warfarin was modified and updated with the relative effectiveness and safety data available from the real-world NAXOS-study and representative Finnish input data for patient characteristics, event risks, mortality, resource use, costs, and quality of life. Apixaban's cost-effectiveness was assessed from health care payer perspective (using 3% per year discount rate) based on incremental cost-effectiveness ratio (ICER, cost per quality-adjusted life year [QALY] gained), probability of cost-effectiveness (at willingness-to-pay [WTP] of 35,000 euros/QALY), and net monetary benefit (NMB). RESULTS: Apixaban increased the average modelled quality-adjusted life-expectancy and reduced the average total health care costs of AF patients when compared to warfarin (+0.14 QALYs, -3691 euros), dabigatran (+0.11 QALYs, -404 euros), and rivaroxaban (+0.03 QALYs, -43 euros). The resulting NMB of apixaban versus warfarin, dabigatran and rivaroxaban was 8723, 4168, and 1129 euros, respectively. The respective probabilities of apixaban being cost-effective against each comparator were 100%, 92.7%, and 64.0%. CONCLUSION: In this modelling study, apixaban dominated other anticoagulants in the Finnish real-life setting.

Laboratory assessment of the direct oral anticoagulants: who can benefit?

Direct oral anticoagulants (DOACs), apixaban, dabigatran, edoxaban, and rivaroxaban, are widely used for the prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation as well as for prevention and treatment of venous thromboembolism. Although DOACs do not require routine laboratory monitoring of anticoagulant effect, there are special situations in which laboratory assessment may be warranted. Laboratory tests include quantitative assays, which measure plasma DOAC levels, and qualitative or semi-quantitative assays, which may be used to screen for the presence of clinically relevant DOAC levels. Indications for laboratory assessment include emergent indications (serious bleeding, urgent surgery, acute ischemic stroke with consideration of thrombolysis) and elective indications (extremes of bodyweight, renal hypo- or hyperfunction, liver disease, suspected drug-drug interactions, suspected gastrointestinal malabsorption). In general, quantitative assays that measure DOAC levels may be used for elective indications, whereas screening assays may be necessary for emergent indications if a quantitative assay with sufficiently rapid turnaround time is not available. Therapeutic ranges for DOACs have not been defined. In lieu of therapeutic ranges, data from pharmacokinetic studies may be used to determine whether a patient's plasma DOAC level falls within the expected range. If it does not, a change in therapy may be warranted. Depending on the clinical scenario, a change in therapy may involve adjustment of the DOAC dose, a change to a different DOAC, or a change to a different class of anticoagulant.

CKD Progression in Medicare Beneficiaries With Nonvalvular Atrial Fibrillation Treated With Apixaban Versus Warfarin.

RATIONALE & OBJECTIVE: Comparing kidney disease progression among patients treated with direct oral anticoagulants (DOACs) versus warfarin has not been well studied. We hypothesized that apixaban would be associated with lower risks of progression of chronic kidney disease (CKD) and progression to incident kidney failure than warfarin in patients with atrial fibrillation (AF). STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Medicare recipients with stage 3, 4, or 5 CKD and incident AF who received a new prescription for apixaban or warfarin from 2013 through 2017. EXPOSURE: Apixaban or warfarin. OUTCOMES: Progression to incident kidney failure or, separately, to a more advanced stage of CKD. ANALYTICAL APPROACH: Marginal structural cause-specific proportional hazards models with inverse probability weighting to estimate marginal hazard ratios (HRs) for each outcome. HRs compared apixaban to warfarin in intention-to-treat and censored-at-drug-switch analyses. RESULTS: 12,816 individuals met inclusion criteria (50.3% received apixaban; 49.7% received warfarin). After weighting, the mean age of the cohort was 80 ± 7 years, 51% were women, and 88% were White. Approximately 84% had stage 3, 15% had stage 4, and 1% had stage 5 CKD. In the intention-to-treat analysis, apixaban, relative to warfarin, was associated with an HR of developing incident kidney failure of 0.98 (95% confidence interval [CI], 0.79-1.22) and of CKD stage progression of 0.90 (95% CI, 0.82-0.99). Corresponding HRs for censored-at-drug-switch analyses were 0.81 (95% CI, 0.56-1.17) and 0.81 (95% CI, 0.70-0.92). Results were similar for a series of subgroup and sensitivity analyses. LIMITATIONS: CKD was defined based on diagnosis codes from claims; findings may not be generalizable to non-Medicare CKD populations. CONCLUSIONS: Apixaban, compared with warfarin, was associated with lower risk of CKD stage progression, but not with incident kidney failure.

Safety and effectiveness of apixaban compared with warfarin among clinically-relevant subgroups of venous thromboembolism patients in the United States Medicare population.

BACKGROUND: The AMPLIFY trial found significantly lower major bleeding (MB) and similar recurrent venous thromboembolism (VTE) risks associated with apixaban vs warfarin among patients with VTE. OBJECTIVES: To compare MB, clinically-relevant non-major (CRNM) bleeding, and recurrent VTE risks among clinically-relevant subgroups of newly diagnosed elderly patients with VTE prescribed apixaban vs warfarin. METHODS: US Medicare patients prescribed apixaban or warfarin within 30 days post-VTE encounter were identified. Propensity score matching (PSM) was used to control for patient characteristics. Cox models were used to assess MB, CRNM bleeding, and recurrent VTE. Subgroup analyses were conducted for index VTE encounter type, index VTE diagnosis type, index VTE etiology, sex, and frailty. RESULTS: Post-PSM, 11,363 matched pairs of patients prescribed apixaban or warfarin were identified. Apixaban had lower MB (Hazard Ratio [HR]:0.76; 95% CI:0.64-0.91) and similar recurrent VTE risks (HR:1.04; 95% CI:0.75-1.43) vs warfarin. No significant interactions were observed between treatment and index VTE encounter type, index VTE diagnosis type, or sex for risk of MB, CRNM bleeding, or recurrent VTE. Significant interactions: frail patients prescribed apixaban had a 15% lower, while non-frail patients prescribed apixaban had 32% lower CRNM bleeding risk vs those prescribed warfarin. Patients with provoked VTE prescribed apixaban trended toward a higher, while those with unprovoked VTE trended toward a lower risk of recurrent VTE vs patients prescribed warfarin. CONCLUSIONS: Apixaban was associated with significantly lower risks of MB and CRNM bleeding, and similar risk of recurrent VTE as compared with warfarin across the overall population and most subgroups.