Pharmacogenetic guided versus standard warfarin dosing for routine clinical care with its pharmacoeconomic impact: a randomized controlled clinical trial.

BACKGROUND: Empirical use of pharmacogenetic test(PGT) is advocated for many drugs, and resource-rich setting hospitals are using the same commonly. The clinical translation of pharmacogenetic tests in terms of cost and clinical utility is yet to be examined in hospitals of low middle income countries (LMICs). AIM: The present study assessed the clinical utility of PGT by comparing the pharmacogenetically(PGT) guided- versus standard of care(SOC)- warfarin therapy, including the health economics of the two warfarin therapies. METHODS: An open-label, randomized, controlled clinical trial recruited warfarin-receiving patients in pharmacogenetically(PGT) guided- versus standard of care(SOC)- study arms. Pharmacogenetic analysis of CYP2C9*2(rs1799853), CYP2C9*3(rs1057910) and VKORC1(rs9923231) was performed for patients recruited to the PGT-guided arm. PT(Prothrombin Time)-INR(international normalized ratio) testing and dose titrations were allowed as per routine clinical practice. The primary endpoint was the percent time spent in the therapeutic INR range(TTR) during the 90-day observation period. Secondary endpoints were time to reach therapeutic INR(TRT), the proportion of adverse events, and economic comparison between two modes of therapy in a Markov model built for the commonest warfarin indication- atrial fibrillation. RESULTS: The study enrolled 168 patients, 84 in each arm. Per-protocol analysis showed a significantly high median time spent in therapeutic INR in the genotype-guided arm(42.85%; CI 21.4-66.75) as compared to the SOC arm(8.8%; CI 0-27.2)(p < 0.00001). The TRT was less in the PG-guided warfarin dosing group than the standard-of-care dosing warfarin group (17.85 vs. 33.92 days) (p = 0.002). Bleeding and thromboembolic events were similar in the two study groups. Lifetime expenditure was ₹1,26,830 in the PGT arm compared to ₹1,17,907 in the SOC arm. The QALY gain did not differ in the two groups(3.9 vs. 3.65). Compared to SOC, the incremental cost-utility ratio was ₹35,962 per QALY gain with PGT test opting. In deterministic and probabilistic sensitivity analysis, the base case results were found to be insensitive to the variation in model parameters. In the cost-effectiveness-acceptability curve analysis, a 90% probability of cost-effectiveness was reached at a willingness-to-pay(WTP) of ₹ 71,630 well below one time GDP threshold of WTP used. CONCLUSION: Clinical efficacy and the cost-effectiveness of the warfarin pharmacogenetic test suggest its routine use as a point of care investigation for patient care in LMICs.

Trends in Oral Anticoagulant Use and Individual Expenditures Across the United States from 2014 to 2020.

BACKGROUND: Landmark clinical trials have expended the indications for the direct oral anticoagulants (DOACs), but contemporary data on usage and expenditure patterns are lacking. OBJECTIVE: This study aimed to assess annual trends in oral anticoagulant (OAC) utilization and expenditure across the United States (US) from 2014 to 2020. METHODS: We utilized the Medical Expenditure Panel Survey (MEPS) to study the trends of use and expenditures of warfarin, dabigatran, rivaroxaban, apixaban, and edoxaban between 2014 and 2020 in the US. Survey respondents reported OAC use within the past year, which was verified against pharmacy records. Payment information was obtained from the respondent's pharmacy and was categorized as third-party or self/out-of-pocket. Potential indications and medical conditions of interest for OAC therapy were identified from respondent-reported medical conditions. We estimated the national number of OAC users and total expenditures across age, sex, race, ethnicity, insurance, and medical condition subgroups. Trends of OAC users' characteristics, expenditure, and number of prescriptions were evaluated using the Mann-Kendall test for trends. RESULTS: Between 2014 and 2020, the number of warfarin users decreased from 3.8 million (70% of all OAC users) to 2.2 million (p = 0.007) [29% of all OAC users], while the number of DOAC users increased from 1.6 million (30% of all OAC users) to 5.4 million (p = 0.003) [70% of all OAC users]. The total expenditure of OACs in the US increased from $3.4 billion in 2014 to $17.8 billion in 2020 (p = 0.003), which was driven by the increase in DOAC expenditures (p = 0.003). CONCLUSIONS: DOACs have replaced warfarin as the preferred OAC in the US. The increased costs associated with DOAC use may decline when generic formulations are approved.

Comparing total medical expenditure between patients receiving direct oral anticoagulants vs warfarin for the treatment of atrial fibrillation: evidence from VA-Medicare dual enrollees.

BACKGROUND: Direct oral anticoagulants (DOACs) are an alternative to warfarin for treatment of atrial fibrillation (AF). Evidence demonstrating the efficacy and safety of DOACs has primarily been from clinical trial settings. The real-world effectiveness of DOACs in specific nontrial populations that differ in age, comorbidity burden, and socioeconomic status is unclear. OBJECTIVE: To compare total downstream medical expenditure between AF patients treated with warfarin and DOACs dually enrolled in the Veterans Affairs (VA) Healthcare System and fee-for-service Medicare. METHODS: This was an exploratory treatment effectiveness study that analyzed VA administrative data and Medicare claims. We examined patients with an incident diagnosis for AF and initiated warfarin or DOAC treatment between 2012 and 2015. The primary outcome was total medical expenditure over 3 years following treatment initiation. To address potential informative censoring, we applied a multipart estimator that extends traditional 2-part models to separate differences between groups due to survival and cost accumulation effects. Inverse probability weighting was applied to address potential treatment selection bias. RESULTS: We identified 31,276 and 17,021 patients receiving warfarin and DOACs, respectively. Mean unadjusted (SD) expenditure was higher for warfarin ($56,265 [$96,666]) compared with DOAC patients ($32,736 [$52,470]). Compared with patients receiving DOACs, adjusted 3-year expenditure was $25,688 (P < 0.001) higher for patients receiving warfarin. CONCLUSIONS: VA patients with AF initiating warfarin incurred markedly higher downstream expenditure compared with similar patients receiving DOACs. The benefits of DOACs found in previous clinical trials were present in this population, suggesting that these DOACs may be the preferred option for treatment of AF in older VA patients. DISCLOSURES: This study was funded by a VA Health Services Research and Development Investigator Initiated Research Award (IIR 15-139). Support for VA/CMS data was provided by the Department of Veterans Affairs, Veterans Health Administration, Office of Research and Development, Health Services Research and Development, VA Information Resource Center (Project Numbers SDR 02-237 and 98-004). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs, the University of Washington, Northeastern University, and Boston University. The authors declare no conflicts of interest. This research includes data obtained from the VHA Office of Performance Measurement (17API2), which resides within the Office of Analytics and Performance Integration (API), under the Office of Quality and Patient Safety (QPS; formerly known as RAPID). An oral presentation documenting a subset of the findings from this study was presented at the 2020 AcademyHealth Annual Research Meeting, delivered virtually on July 29, 2020.

Cost-effectiveness analysis of apixaban compared to other direct oral anticoagulants for prevention of stroke in Austrian atrial fibrillation patients.

OBJECTIVES: Several direct oral anticoagulants (DOACs) have been approved by the European Medicines Agency since 2008. The aim of the present cost-effectiveness-analysis was to analyze apixaban compared to other DOACs and vitamin K antagonists (warfarin) in Austria. METHODS: A cost-utility-model was developed to simulate lifetime-costs and quality-adjusted-life-years of DOACs and warfarin, based on a published Markov-Model and 23 randomized trials with 94,656 atrial-fibrillation (AF) patients. Each year, a patient has a probability of suffering a clinically relevant (extracranial) bleed, an intracranial hemorrhage (ICH), an ischemic stroke or a myocardial infarction (MI), remaining healthy, or deceasing. Direct-costs (2018€) were derived from published sources from the payer's perspective. RESULTS: In the base-case, warfarin had the lowest cost of 12,968 € (95%-CI±593 €) followed by apixaban (15,269 €±661 €), edoxaban (15,534 €±641 €), dabigatran (15,687 €±667 €), and rivaroxaban (17,522 €±764 €). Apixaban had the highest quality-adjusted-life-years estimate at 5.45 (SD, 0.06). In a Monte-Carlo probabilistic sensitivity analysis, apixaban was cost-effective vs. edoxaban, dabigatran, warfarin, and rivaroxaban in 85.6%, 79.0%, 76.4%, and 61.2% of the simulations, respectively. CONCLUSION: In patients with AF and an increased risk of stroke, prophylaxis with apixaban was highly cost-effective from the perspective of the Austrian health-care system.

Clinical and budget impacts of changes in oral anticoagulation prescribing for atrial fibrillation.

OBJECTIVE: To assess temporal clinical and budget impacts of changes in atrial fibrillation (AF)-related prescribing in England. METHODS: Data on AF prevalence, AF-related stroke incidence and prescribing for all National Health Service general practices, hospitals and registered patients with hospitalised AF-related stroke in England were obtained from national databases. Stroke care costs were based on published data. We compared changes in oral anticoagulation prescribing (warfarin or direct oral anticoagulants (DOACs)), incidence of hospitalised AF-related stroke, and associated overall and per-patient costs in the periods January 2011-June 2014 and July 2014-December 2017. RESULTS: Between 2011-2014 and 2014-2017, recipients of oral anticoagulation for AF increased by 86.5% from 1 381 170 to 2 575 669. The number of patients prescribed warfarin grew by 16.1% from 1 313 544 to 1 525 674 and those taking DOACs by 1452.7% from 67 626 to 1 049 995. Prescribed items increased by 5.9% for warfarin (95% CI 2.9% to 8.9%) but by 2004.8% for DOACs (95% CI 1848.8% to 2160.7%). Oral anticoagulation prescription cost rose overall by 781.2%, from £87 313 310 to £769 444 028, (£733,466,204 with warfarin monitoring) and per patient by 50.7%, from £293 to £442, giving an incremental cost of £149. Nevertheless, as AF-related stroke incidence fell by 11.3% (95% CI -11.5% to -11.1%) from 86 467 in 2011-2014 to 76 730 in 2014-2017 with adjustment for AF prevalence, the overall per-patient cost reduced from £1129 to £840, giving an incremental per-patient saving of £289. CONCLUSIONS: Despite nearly one million additional DOAC prescriptions and substantial associated spending in the latter part of this study, the decline in AF-related stroke led to incremental savings at the national level.

Non-warfarin oral anticoagulant copayments and adherence in atrial fibrillation: A population-based cohort study.

BACKGROUND: In patients with atrial fibrillation, incomplete adherence to anticoagulants increases risk of stroke. Non-warfarin oral anticoagulants (NOACs) are expensive; we evaluated whether higher copayments are associated with lower NOAC adherence. METHODS: Using a national claims database of commercially-insured patients, we performed a cohort study of patients with atrial fibrillation who newly initiated a NOAC from 2012 to 2018. Patients were stratified into low (<$35), medium ($35-$59), or high (≥$60) copayments and propensity-score weighted based on demographics, insurance characteristics, comorbidities, prior health care utilization, calendar year, and the NOAC received. Follow-up was 1 year, with censoring for switching to a different anticoagulant, undergoing an ablation procedure, disenrolling from the insurance plan, or death. The primary outcome was adherence, measured by proportion of days covered (PDC). Secondary outcomes included NOAC discontinuation (no refill for 30 days after the end of NOAC supply) and switching anticoagulants. We compared PDC using a Kruskal-Wallis test and rates of discontinuation and switching using Cox proportional hazards models. RESULTS: After weighting patients across the 3 copayment groups, the effective sample size was 17,558 patients, with balance across 50 clinical and demographic covariates (standardized differences <0.1). Mean age was 62 years, 29% of patients were female, and apixaban (43%), and rivaroxaban (38%) were the most common NOACs. Higher copayments were associated with lower adherence (P < .001), with a PDC of 0.82 (Interquartile range [IQR] 0.36-0.98) among those with high copayments, 0.85 (IQR 0.41-0.98) among those with medium copayments, and 0.88 (IQR 0.41-0.99) among those with low copayments. Compared to patients with low copayments, patients with high copayments had higher rates of discontinuation (hazard ratio [HR] 1.13, 95% confidence interval [CI] 1.08-1.19; P < .001). CONCLUSIONS: Among atrial fibrillation patients newly initiating NOACs, higher copayments in commercial insurance were associated with lower adherence and higher rates of discontinuation in the first year. Policies to lower or limit cost-sharing of important medications may lead to improved adherence and better outcomes among patients receiving NOACs.

Cost-effectiveness of rivaroxaban versus warfarin in non-valvular atrial fibrillation patients with chronic kidney disease in China.

WHAT IS KNOWN AND OBJECTIVE: In non-valvular atrial fibrillation (NVAF) patients with chronic kidney disease (CKD), rivaroxaban was not inferior to warfarin in preventing stroke and systemic embolism. However, a comparative evaluation of the cost-effectiveness of rivaroxaban and warfarin therapies for NVAF patients at different renal function levels has not yet been reported, and this study aimed to estimate the cost-effectiveness of rivaroxaban compared with warfarin in Chinese NVAF patients with CKD. METHODS: A Markov model was constructed to estimate quality-adjusted life years (QALYs) and lifetime costs associated with the use of rivaroxaban relative to warfarin in patients with NVAF at different estimated glomerular filtration rate (eGFR) levels as follows: 30 to <50, 50 to <80 and ≥80 mL/min. Input parameters were sourced from the clinical literature. Probabilistic sensitivity analyses were performed to assess model uncertainty. RESULTS AND DISCUSSION: The incrementalQALYs with rivaroxaban was slightly increased by approximately 0.3 QALY as compared with that with warfarin in all the subgroups, resulting in an ICER of $9,736/QALY (eGFR, 30 to <50 mL/min), $9,758/QALY (50 to <80 mL/min) and $9,969/QALY (≥80 mL/min). The probabilistic sensitivity analysis suggested a chance of >80% that the ICER would be lower than the willingness-to-pay threshold of three times the GDP of China in 2019 in all the subgroups. Results were consistent even under the assumption of anticoagulant discontinuation after major bleeding events. The model was most sensitive to event-free-related utility and survival rates. WHAT IS NEW AND CONCLUSION: The existing evidence supports the cost-effectiveness of rivaroxaban therapy as an alternative anticoagulant to warfarin for patients with NVAF at different renal function levels.

Cost-effectiveness of antithrombotic agents for atrial fibrillation in older adults at risk for falls: a mathematical modelling study.

BACKGROUND: Antithrombotic drugs decrease stroke risk in patients with atrial fibrillation, but they increase bleeding risk, particularly in older adults at high risk for falls. We aimed to determine the most cost-effective antithrombotic therapy in older adults with atrial fibrillation who are at high risk for falls. METHODS: We conducted a mathematical modelling study from July 2019 to March 2020 based on the Ontario, Canada, health care system. We derived the base-case age, sex and fall risk distribution from a published cohort of older adults at risk for falls, and the bleeding and stroke risk parameters from an atrial fibrillation trial population. Using a probabilistic microsimulation Markov decision model, we calculated quality-adjusted life years (QALYs), total cost and incremental cost-effectiveness ratios (ICERs) for each of acetylsalicylic acid (ASA), warfarin, apixaban, dabigatran, rivaroxaban and edoxaban. Cost data were adjusted for inflation to 2018 values. The analysis used the Ontario public payer perspective with a lifetime horizon. RESULTS: In our model, the most cost-effective antithrombotic therapy for atrial fibrillation in older patients at risk for falls was apixaban, with an ICER of $8517 per QALY gained (5.86 QALYs at $92 056) over ASA. It was a dominant strategy over warfarin and the other antithrombotic agents. There was moderate uncertainty in cost-effectiveness ranking, with apixaban as the preferred choice in 66% of model iterations (given willingness to pay of $50 000 per QALY gained); edoxaban, 30 mg, was preferred in 31% of iterations. Sensitivity analysis across ranges of age, bleeding risk and fall risk still favoured apixaban over the other medications. INTERPRETATION: From a public payer perspective, apixaban is the most cost-effective antithrombotic agent in older adults at high risk for falls. Health care funders should implement strategies to encourage use of the most cost-effective medication in this population.

Cost-effectiveness of direct oral anticoagulants versus vitamin K antagonist in atrial fibrillation: A study protocol using Real-World Data from Catalonia (FantasTIC Study).

BACKGROUND: Anticoagulant therapy is used for stroke prevention and proved to be effective and safe in the long term. The study aims to analyse the cost-effectiveness relationship of using of direct-acting oral anticoagulants vs vitamin K antagonists to prevent ischaemic stroke in patients with nonvalvular atrial fibrillation, including all the active ingredients marketed in Spain, prescribed for 2 years in the Primary Care service of the Institut Català de la Salut. METHODS: Population-based cohort study, in which the cost of the 2 treatment groups will be evaluated. Direct costs (pharmacy, primary care, emergency and hospitalization) and indirect costs (lost productivity) will be included from a social perspective. Effectiveness (assessed as the occurrence of a health event, the 1 of primary interest being stroke) will be determined, with a 2-year time horizon and a 3% discount rate. The average cost of the 2 groups of drugs will be compared using a regression model to determine the factors with the greatest influence on determining costs. We will carry out a univariate ('one-way') deterministic sensitivity analysis. DISCUSSION: We hope to provide relevant information about direct and indirect costs of oral anticoagulants, which, together with aspects of effectiveness and safety, could help shape the consensual decision-making of evaluating bodies.

Warfarin control in Hong Kong clinical practice: a single-centre observational study.

INTRODUCTION: Time in therapeutic range (TTR) assesses the safety and effectiveness of warfarin therapy using the international normalised ratio. This study investigated the TTR in Hong Kong patients using both European and Japanese therapeutic ranges and patients' economic and clinical outcomes. Predictors of poor warfarin control and patient knowledge concerning warfarin therapy were assessed. METHODS: A 5-month observational study with retrospective and prospective components was conducted in the Prince of Wales Hospital. The study examined electronic patient records of patients who received warfarin for at least 1 year during the period from January 2010 to August 2015. Patient knowledge was assessed via phone interview using the Oral Anticoagulation Knowledge (OAK) test. RESULTS: In total, 259 patients were included; 174 completed the OAK test. The calculated mean TTR was 40.2±17.1% (European therapeutic range), compared with 49.1±16.1% (Japanese therapeutic range) [P<0.001]. Mean TTR was higher in patients with atrial fibrillation than in patients with prosthetic heart valve (P<0.001). The abilities of TTR to predict clinical and economic outcomes were comparable between European and Japanese therapeutic ranges. Patients with ideal TTR had fewer clinical complications and lower healthcare costs. Patients with younger age exhibited worse TTR, as did those with concurrent use of furosemide, famotidine, or simvastatin. Mean OAK test score was 54.1%. Only 24 (13.8%) patients achieved a satisfactory overall score of ≥75% in the test. CONCLUSION: Warfarin use in Hong Kong patients was poorly controlled, regardless of indication. Patient knowledge concerning warfarin use was suboptimal; thus, additional patient education is warranted regarding warfarin.

Comparison of Anticoagulants for Postoperative Atrial Fibrillation After Coronary Artery Bypass Grafting: A Pilot Study.

BACKGROUND: Direct-acting oral anticoagulants are indicated for the treatment of nonvalvular atrial fibrillation, but their use in patients after undergoing cardiac surgery is poorly defined despite a high prevalence of postoperative atrial fibrillation in this population. METHODS: Patients diagnosed with postoperative atrial fibrillation were prospectively randomized to warfarin or apixaban. Safety, efficacy, and economic outcomes were evaluated until their 4- to 6-week postoperative appointment. RESULTS: While this pilot study was not powered to determine a difference in safety or efficacy, adverse event rates were similar to the published literature. It was noted that a patient's course of therapy when utilizing apixaban was significantly less costly than warfarin when including medication, bridging, and laboratory expenses. CONCLUSION: Apixaban and warfarin both appeared to be safe and effective for anticoagulation throughout the duration of this pilot study in treating postoperative atrial fibrillation after coronary artery bypass grafting. Apixaban was associated with significantly less expense when bridging and monitoring costs were included in addition to medication expense.

Comparative Clinical and Economic Outcomes Associated with Warfarin Versus Apixaban in the Treatment of Patients with Venous Thromboembolism in a Large U.S. Commercial Claims Database.

BACKGROUND: Venous thromboembolism (VTE), constituting deep vein thrombosis (DVT) and pulmonary embolism (PE), is a common cause of vascular-related morbidity and mortality, resulting in a significant clinical and economic burden in the United States each year. Clinical guidelines recommend that patients with DVT and PE without cancer should be initiated on anticoagulation therapy with a direct oral anticoagulant over a vitamin K antagonist. Yet there is limited real-world evidence comparing the economic burden of warfarin and apixaban in treating VTE patients in a large commercially insured population. OBJECTIVE: To compare safety and effectiveness of warfarin and apixaban and evaluate associated economic burden in treating VTE patients in a large U.S. commercial health care claims database. METHODS: The PharMetrics Plus database was used to identify oral anticoagulant (OAC)-naive patients aged ≥ 18 years who initiated apixaban or warfarin within 30 days of a qualifying VTE encounter and had continuous health plan enrollment with medical and pharmacy benefits for 6 months before treatment initiation. Apixaban initiators and warfarin initiators were matched using the propensity score matching (PSM) technique. Cox proportional hazard models were used to assess and compare the risk of major bleeding (MB), clinically relevant nonmajor (CRNM) bleeding, and recurrent VTE. Generalized linear models were used to assess and compare the all-cause health care costs. A 2-part model with bootstrapping was used to evaluate MB- and recurrent VTE-related medical costs. RESULTS: Among 25,193 prematched patients, 13,421 (53.3%) were prescribed warfarin and 11,772 (46.7%) were prescribed apixaban. After 1:1 PSM, 8,858 matched warfarin-apixaban pairs were selected with a mean follow-up of 109 days and 103 days, respectively. Warfarin was associated with a significantly higher risk of MB (HR = 1.52, 95% CI = 1.14-2.04), CRNM bleeding (HR = 1.27, 95% CI = 1017.15-1.40), and recurrent VTE (HR = 1.50, 95% CI = 1.24-1.82) compared with apixaban. Warfarin patients had significantly higher all-cause medical costs per patient per month (PPPM; $2,333 vs. $1,992; P = 0.001), MB-related costs PPPM ($112 vs. $65; P = 0.020), and recurrent VTE-related costs PPPM ($287 vs. $206; P = 0.014) compared with apixaban patients. Warfarin patients had similar all-cause total health care costs PPPM ($2,630 vs. $2,420; P = 0.051) compared with apixaban patients. CONCLUSIONS: Warfarin use was associated with a higher risk of MB, CRNM bleeding, and recurrent VTE compared with apixaban. Warfarin use was also associated with higher all-cause medical costs, MB-related medical costs, and recurrent VTE-related costs PPPM compared with apixaban. DISCLOSURES: This study was funded by Bristol Myers Squibb and Pfizer, which were also involved in the study design, as well as writing and revising of the manuscript. Guo, Rajpura, Okano, and Rosenblatt are employees of Bristol Myers Squibb. Hlavacek, Mardekian, and Russ are employees of Pfizer. Keshishian, Sah, Delinger, and Mu are employees of SIMR, LLC, which received funding from the study sponsors to conduct this study.

Comparing outcomes and costs among warfarin-sensitive patients versus warfarin-insensitive patients using The Right Drug, Right Dose, Right Time: Using genomic data to individualize treatment (RIGHT) 10K warfarin cohort.

Oral anticoagulant (OAC) therapy has been the main treatment approach for stroke prevention for decades. Warfarin is the most widely prescribed OAC in the United States, but is difficult to manage due to variability in dose requirements across individuals. Pharmacogenomics may mitigate risk concerns related to warfarin use by fostering the opportunity to facilitate individualized medicine approaches to warfarin treatment (e.g., genome-guided dosing). While various economic evaluations exist examining the cost-effectiveness of pharmacogenomics testing for warfarin, few observational studies exist to support these studies, with even fewer using genotype as the main exposure of interest. We examined a cohort of individuals initiating warfarin therapy between 2004 and 2017 and examined bleeding and cost outcomes for the year following initiation using Mayo Clinic's billing and administrative data, as well the Mayo Clinic Rochester Cost Data Warehouse. Analyses included descriptive summaries, comparison of characteristics across exposure groups, reporting of crude outcomes, and multivariate analyses. We included N = 1,143 patients for analyses. Just over a third of our study population (34.9%) carried a warfarin-sensitive phenotype. Sensitive individuals differed in their baseline characteristics by being of older age and having a higher number of comorbid conditions; myocardial infarction, diabetes, and cancer in particular. The occurrence of bleeding events was not significantly different across exposure groups. No significant differences across exposure groups existed in either the likelihood of incurring all-cause healthcare costs or in the magnitude of those costs. Warfarin-sensitive individuals were no more likely to utilize cardiovascular-related healthcare services; however, they had lower total and inpatient cardiovascular-related costs compared to warfarin-insensitive patients. No significant differences existed in any other categories of costs. We found limited evidence that warfarin-sensitive individuals have different healthcare spending than warfarin-insensitive individuals. Additional real-world studies are needed to support the traditional economic evaluations currently existing in the literature.

Comparison of Healthcare Resource Utilization and Costs between Rivaroxaban and Warfarin for Nonvalvular Atrial Fibrillation in a Skilled Nursing Facility Setting.

BACKGROUND: Use of direct-acting oral anticoagulants for patients with nonvalvular atrial fibrillation (NVAF) in skilled nursing facilities (SNFs) is increasing. Rivaroxaban is commonly used in this setting as an alternative to warfarin, based on comparable or increased efficacy in preventing stroke and a similar or lower risk of major bleeding. OBJECTIVE: The aim of this study was to compare healthcare resource utilization (HCRU) and costs between NVAF patients receiving rivaroxaban or warfarin in SNFs. METHODS: This retrospective study examined de-identified claims from Optum® Clinformatics® Extended Data Mart (1 January 2013-31 December 2017). Eligible patients had an AF diagnosis, were prescribed rivaroxaban or warfarin during an SNF stay, and had one or more such prescriptions filled in the 6 months preceding the stay. Patients were excluded if they received another oral anticoagulant or had evidence of valvular heart disease, mitral stenosis, or organ/tissue transplant. HCRU, mean number of events, and all-cause healthcare costs during the index SNF stay were reported. Results were also reported on a per-patient-per-month (PPPM) basis. Exploratory analyses at different time periods were also conducted. RESULTS: Overall, 4423 rivaroxaban patients and 22,796 warfarin patients were identified prior to inverse probability of treatment weighting adjustment. Index SNF stay was significantly shorter among rivaroxaban-treated patients (35.8 ± 35.8 days) versus warfarin (40.1 ± 46.3 days; p < 0.0001). During the SNF stay, overall HCRU was lower for the rivaroxaban cohort versus the warfarin cohort. All-cause total costs were significantly reduced for rivaroxaban ($6450 ± $10,379) versus warfarin ($7640 ± $16,556; p < 0.0001), and similar results were observed when calculated on a PPPM basis. During the 1-year post-index period, PPPM all-cause total costs were significantly lower with rivaroxaban versus warfarin ($4135 vs. $4561; p < 0.0001). CONCLUSION: In this SNF setting, HCRU and costs were lower among patients with NVAF who were experienced users of rivaroxaban compared with those who were experienced users of warfarin. These findings may help inform clinical decision making to reduce the economic burden of NVAF among older adults in SNFs.

Comparison of inpatient admission rates of patients treated with apixaban vs. warfarin for venous thromboembolism in the emergency department.

Objectives: This study evaluated inpatient admission status, hospitalization length of stay (LOS), hospital costs, and readmissions of patients who were diagnosed with venous thromboembolism (VTE) and treated with apixaban or warfarin in the emergency department (ED).Methods: Patients (≥18 years) with an ED visit with a primary discharge diagnosis code of VTE were identified from the Premier Hospital database (8/1/2014-5/31/2018). Patients who received apixaban or warfarin during the ED visit were selected and grouped into two treatment cohorts. Outcomes of ED disposition (discharged or admitted to the inpatient setting), hospital LOS, hospital cost of index event, and rate of 1-month readmissions were compared for the study cohorts.Results: Of the overall study population, 30.5% (n = 12,174; mean age: 59.7 years) received apixaban and 69.5% (n = 27,767; mean age: 59.3 years) received warfarin for VTE in the ED. After adjusting for patient and hospital characteristics, the regression analysis showed that apixaban was associated with a significantly lower likelihood of admission to the inpatient setting vs. warfarin (Odds Ratio [OR]: 0.12, 95% Confidence Interval [CI]: 0.12 to 0.13; p < 0.001). Correspondingly, mean index hospital LOS was 1.42 days shorter (95% CI: -1.47 to -1.36; p < 0.001) and mean index event hospital cost per patient was significantly lower by $4,276 ($3,732 [95% CI: $3,565 to $3,907] vs. $8,008 [95% CI: $7,676 to $8,355]; p < 0.001). Also, the likelihood of all-cause 1-month readmission was significantly lower for patients treated with apixaban vs. warfarin (OR: 0.85, 95% CI: 0.79 to 0.92; p < 0.001).Conclusions: In the real-world setting, VTE patients with an ED visit who were treated with apixaban vs. warfarin had a lower likelihood of being admitted to the inpatient setting, which was reflected in shorter average LOS and lower average index event cost. Additionally, the risk of 1-month readmission was also lower for patients treated with apixaban vs. warfarin.

Current status and factors influencing oral anticoagulant therapy among patients with non-valvular atrial fibrillation in Jiangsu province, China: a multi-center, cross-sectional study.

BACKGROUND: It has been reported that oral anticoagulation (OAC) is underused among Chinese patients with non-valvular atrial fibrillation (NVAF). Non-vitamin K antagonist oral anticoagulants (NOAC) have been recommended by recent guidelines and have been covered since 2017 by the Chinese medical insurance; thus, the overall situation of anticoagulant therapy may change. The aim of this study was to explore the current status of anticoagulant therapy among Chinese patients with NVAF in Jiangsu province. METHODS: This was a multi-center, cross-sectional study that was conducted in seven hospitals from January to September in 2017. The demographic characteristics and medical history of the patients were collected by questionnaire and from the medical records. Multivariate logistic regression was used to identify factors associated with anticoagulant therapy. RESULTS: A total of 593 patients were included in the analysis. A total of 35.6% of the participants received OAC (11.1% NOAC and 24.5% warfarin). Of those patients with a high risk of stroke, 11.1% were on NOAC, 24.8% on warfarin, 30.6% on aspirin, and 33.6% were not on medication. Self-paying, duration of AF ≥5 years were negatively associated with anticoagulant therapy in all patients (OR 1.724, 95% CI 1.086~2.794; OR 1.471, 95% CI 1.006~2.149, respectively), whereas, permanent AF was positively associated with anticoagulant therapy (OR 0.424, 95% CI 0.215~0.839). Among patients with high risk of stroke, self-paying and increasing age were negatively associated with anticoagulant therapy (OR 2.305, 95% CI 1.186~4.478; OR 1.087, 95% CI 1.041~1.135, respectively). CONCLUSIONS: Anticoagulant therapy is positively associated with permanent AF and negatively associated with self-paying, duration of AF > 5 years. Furthermore, the current status of anticoagulant therapy among Chinese patients with NVAF in Jiangsu province does not appear optimistic. Therefore, further studies should focus on how to improve the rate of OAC use among NVAF patients. In addition, policy makers should pay attention to the economic situation of the patients with NVAF using NOAC. TRIAL REGISTRATION: 2,017,029. Registered 20 March 2017 (retrospectively registered).

Cost-Effectiveness Analysis of Non-Vitamin K Antagonist Oral Anticoagulants Versus Warfarin in Thai Patients With Non-Valvular Atrial Fibrillation.

BACKGROUND: Non-vitamin K antagonist oral anticoagulants (NOACs) have been recommended as preferred options for stroke prevention in patients with atrial fibrillation (AF) versus warfarin by guidelines worldwide. AIM: This study aimed to evaluate the cost-effectiveness of each NOAC in a Thai health care environment, a country with upper middle-income economies based on the World Bank's classification. METHOD: A lifetime Markov model was created from a Thai societal perspective. The model consisted of 19 health states separated into two cycles: event cycle and consequence cycle. The consequences of AF included in the model were ischaemic stroke, intracranial haemorrhage, extracranial haemorrhage, and myocardial infarction. All NOACs available in Thailand (dabigatran 150 mg and 110 mg twice daily; rivaroxaban 20 mg once daily; apixaban 5 mg twice daily; edoxaban 60 mg and 30 mg once daily) were assessed using warfarin with an international normalised ratio of 2-3 as the reference. Inputs were a combination of published literature and local data when available. A willingness-to-pay of 160,000 Thai baht (THB)/quality-adjusted life year (QALY) was used as the threshold of being cost-effective. Incremental cost-effectiveness ratios and cost-effectiveness acceptability curves were estimated. RESULTS: All NOACs were not cost-effective strategies for the Thai AF population. The ranking of incremental cost-effectiveness ratios from lowest to highest were apixaban 5 mg twice daily (THB 692,136 or US$21,862) followed by edoxaban 60 mg once daily (THB 911,772 or US$28,799), edoxaban 30 mg once daily (THB 913,749 or US$28,861), dabigatran 150 mg twice daily (THB 1,102,106 or US$34,811), dabigatran 110 mg twice daily (THB 1,195,347 or US$37,756), and rivaroxaban 20 mg once daily (THB 1,347,650 or US$42,566). Cost-effectiveness acceptability curve indicated that apixaban had the highest potential to be a cost-effective strategy versus other NOACs. CONCLUSIONS: Our findings indicated that all NOACs were not cost-effective in the Thai AF population. Of the NOACs, apixaban may be the most likely to be cost-effective. These data may be useful for policymakers to perform a comprehensive evaluation of these agents for formulary decision and pricing negotiation.

Factors That Affect Time to Switch From Warfarin to a Direct Oral Anticoagulant After Change in the Reimbursement Criteria in Patients With Atrial Fibrillation.

BACKGROUND: Anticoagulation therapy is recommended for stroke prevention in high-risk patients with atrial fibrillation (AF). This study aimed to estimate the time to switch from warfarin to a direct oral anticoagulant (DOAC) and identify the factors associated with it. METHODS: By using claims data, we studied 7111 warfarin-using patients with nonvalvular AF who were aged ≥65 years. The Kaplan-Meier analysis was performed to estimate the time to switch from warfarin to a DOAC, and Cox proportional hazard regression analysis was used to estimate the influencing factors. RESULTS: Approximately one-third of the patients (2403, 33.8%) switched from warfarin to a DOAC during the study period. Female sex, aged between 75 and 79 years, having a Medical Aid or Patriots and Veterans Insurance, hypertension, and history of prior stroke, and transient ischemic attack or thromboembolism (prior stroke/TIA/TE) were associated with a significantly shorter time to switch. The odds of switching to a DOAC were increased by approximately 1.2-fold in the women and 1.4-fold in the patients with prior stroke/TIA/TE. CONCLUSIONS: Approximately one-third of the warfarin-using patients switched from warfarin to a DOAC within 6 months after the change in the DOAC reimbursement criteria. In the Cox proportional hazard regression analysis, the factors that affected anticoagulant switching from warfarin to a DOAC were female sex and history of prior stroke/TIA/TE.

Cost-effectiveness of rivaroxaban versus warfarin for stroke prevention in non-valvular atrial fibrillation in the Japanese healthcare setting.

Aims: This article aimed to examine the cost-effectiveness of rivaroxaban in comparison to warfarin for stroke prevention in Japanese patients with non-valvular atrial fibrillation (NVAF), from a public healthcare payer's perspective.Materials and methods: Baseline event risks were obtained from the J-ROCKET AF trial and the treatment effect data were taken from a network meta-analysis. The other model inputs were extracted from the literature and official Japanese sources. The outcomes included the number of ischaemic strokes, myocardial infarctions, systemic embolisms and bleedings avoided, life-years, quality-adjusted life-years (QALYs), incremental costs and incremental cost-effectiveness ratio (ICER). The scenario analysis considered treatment effect data from the same network meta-analysis.Results: In comparison with warfarin, rivaroxaban was estimated to avoid 0.284 ischaemic strokes per patient, to increase the number of QALYs by 0.535 per patient and to decrease the total costs by ¥118,892 (€1,011.11) per patient (1 JPY = 0.00850638 EUR; XE.com, 7 October 2019). Consequently, rivaroxaban treatment was found to be dominant compared to warfarin. In the scenario analysis, the ICER of rivaroxaban versus warfarin was ¥2,873,499 (€24,446.42) per QALY.Limitations: The various sources of data used resulted in the heterogeneity of the cost-effectiveness analysis results. Although, rivaroxaban was cost-effective in the majority of cases.Conclusion: Rivaroxaban is cost-effective against warfarin for stroke prevention in Japanese patients with NVAF, giving the payer WTP of 5,000,000 JPY.

Modeling patients' time, travel, and monitoring costs in anticoagulation management: societal savings achievable with the shift from warfarin to direct oral anticoagulants.

BACKGROUND: Anticoagulation therapy is used for atrial fibrillation (AF) patients for reducing the risk of cardioembolic complications such as stroke. The previously recommended anticoagulant, warfarin, has a narrow therapeutic window, and it requires regular laboratory monitoring, unlike direct oral anticoagulants (DOAC). From a societal perspective, it is important to measure time and travel costs associated with warfarin monitoring to better compare the total therapy costs of these two alternative forms of anticoagulation management. In this study we design a georeferenced cost model to investigate societal savings achievable with the shift from warfarin to DOACs in the study region of North Karelia in Eastern Finland. METHODS: Individual-level patient data of 6519 AF patients was obtained from the regional patient database. Patients' geocoded home addresses and other GIS data were used to perform a network analysis for the optimal routes for warfarin monitoring visits. These measures of revealed accessibility were then used in the cost model to measure monetary time and travel costs in addition to direct healthcare costs of anticoagulation management. RESULTS: The share of time and travel costs in warfarin monitoring is 26.6% of the total therapy costs in our study region. With current drug retail prices in Finland, the societal expense of anticoagulation management is only 2.6% higher with DOACs than in the baseline with warfarin. However, when 25% lower distributor's prices are used, the total societal cost decreases by 13.6% with DOACs. CONCLUSIONS: Our results indicate that patients' time and travel costs critically increase the societal cost of warfarin therapy; and despite the higher price of DOACs, they are already cost-efficient alternatives to warfarin in anticoagulation management. In the future, the cost of AF complications should be included in the cost comparison between warfarin and DOACs. Our modeling approach applies to different geographical regions and to different healthcare processes requiring patient monitoring.