Novel oral anticoagulants versus warfarin therapy at various levels of anticoagulation control in atrial fibrillation--a cost-effectiveness analysis

Cost-Effectiveness Analysis of Pharmacogenomics (PGx)-Based Warfarin, Apixaban, and Rivaroxaban Versus Standard Warfarin for the Management of Atrial Fibrillation in Ontario, Canada

OBJECTIVE

To assess the cost-effectiveness of pharmacogenomics (PGx)-based warfarin (i.e., warfarin dosing following genetic testing), apixaban, and rivaroxaban oral anticoagulation versus standard warfarin for the treatment of newly diagnosed patients with nonvalvular atrial fibrillation (AF) aged ≥ 65 years.

METHODS

We developed a Markov decision-analytic model to compare costs [2017 Canadian dollars (C$)] and quality-adjusted life years (QALYs) from the Ontario health care payer perspective over a life-time horizon. The parameters used in the model were derived from the published literature, the Ontario health care administrative database, and expert opinion. To account for the uncertainty of model parameters, we conducted extensive deterministic and probabilistic sensitivity analyses. The results were summarized using incremental cost-effectiveness ratios (ICERs) and cost-effectiveness acceptability curves.

RESULTS

We found that PGx-based warfarin had an ICER of C$17,584/QALY compared with standard warfarin, and apixaban had an ICER of C$64,590/QALY compared with PGx-based warfarin in our base-case analysis. Rivaroxaban was extendedly dominated by PGx-based warfarin and apixaban. The probabilistic sensitivity analysis showed that apixaban, rivaroxaban, PGx-based warfarin, and standard warfarin were cost-effective at some willingness-to-pay (WTP) thresholds. PGx-based warfarin had a higher probability of being cost-effective than apixaban (51.3% versus 14.3%) at a WTP threshold of C$50,000/QALY. At a WTP threshold of C$100,000/QALY, apixaban had a higher probability of being cost-effective than PGx-based warfarin (54.6% versus 22.6%).

CONCLUSION

We found that PGx-based warfarin for patients with AF is cost-effective at a WTP threshold of C$50,000/QALY. Apixaban had a higher probability of being cost-effective (> 50%) at a WTP threshold of C$93,000/QALY.

Methods for Economic Evaluations of Novel Oral Anticoagulants in Patients with Atrial Fibrillation: A Systematic Review

BACKGROUND

Atrial fibrillation (AF) is a severe epidemiological and public health concern among the elderly population worldwide, with substantial economic and social burdens. Economic evaluations can play an essential role in optimizing the utilization of scarce resources. In recent years, the number of economic evaluation studies related to AF has increased due to the rising number of AF patients, the continuous updating of clinical data, and the emergence of real-world evidence. However, there are still deficiencies in model settings and parameter sources in relevant studies.

OBJECTIVE

This study aims to review the existing economic evaluations of novel oral anticoagulants (NOACs) in patients with AF and summarize the evidence and methods applied.

METHODS

A comprehensive and systematic search was conducted on electronic databases, including PubMed, Embase, Web of Science (WOS), and The Cochrane Library, from the date of database creation to November 2022. The reporting quality of included literature was assessed using the Consolidated Health Economic Evaluation Reporting Standards 2022 (CHEERS 2022) statement.

RESULTS

A total of 102 studies were included in the review, with 200 comparisons between NOACs and vitamin K antagonists (VKAs), as well as 58 comparisons between different NOACs. The healthcare sector and payer perspectives were the most common, and accordingly, the majority of the evaluations considered only direct medical costs. Most studies used Markov cohort models with the number of health states ranging from 4 to 29. Of included studies, 80 (78%) considered event recurrence and complications, and 78 (76%) considered discontinuation and second-line therapy. All of the studies applied uncertainty analysis to explore the robustness of the results. Of all 200 NOACs-VKAs comparisons, 149 (75%) showed that NOACs were more cost-effective; this proportion was 84% (139 out of 165) in high-income countries but decreased to 29% (10 out of 35) in middle- and low-income countries. Most (82%) of the 28 items in the CHEERS 2022 checklist were elucidated in the majority of included studies. A minority (only 39%) of included studies demonstrated high reporting quality.

CONCLUSION

NOACs may be more cost-effective than VKAs in patients with AF, but this conclusion applies to high-income countries, whereas VKAs may be more cost-effective in middle- and low-income countries. The reporting quality of included studies was variable, and certain methodological issues were presented. This study highlights the economic evaluation methodology of NOACs in patients with AF and provides recommendations for modeling methods and future studies.

Economic evaluation in cardiac electrophysiology: Determining the value of emerging technologies

Cardiac electrophysiology is a constantly evolving speciality that has benefited from technological innovation and refinements over the past several decades. Despite the potential of these technologies to reshape patient care, their upfront costs pose a challenge to health policymakers who are responsible for the assessment of the novel technology in the context of increasingly limited resources. In this context, it is critical for new therapies or technologies to demonstrate that the measured improvement in patients' outcomes for the cost of achieving that improvement is within conventional benchmarks for acceptable health care value. The field of Health Economics, specifically economic evaluation methods, facilitates this assessment of value in health care. In this review, we provide an overview of the basic principles of economic evaluation and provide historical applications within the field of cardiac electrophysiology. Specifically, the cost-effectiveness of catheter ablation for both atrial fibrillation (AF) and ventricular tachycardia, novel oral anticoagulants for stroke prevention in AF, left atrial appendage occlusion devices, implantable cardioverter defibrillators, and cardiac resynchronization therapy will be reviewed.

Cost effectiveness of rivaroxaban versus warfarin among nonvalvular atrial fibrillation patients in Saudi Arabia: A Single-Center retrospective cohort study

Background

Rivaroxaban is a novel oral anticoagulant (NOAC) that is commonly used for stroke prevention among patients with atrial fibrillation (AF). However, its cost effectiveness in reducing the risk of hospitalization and mortality in comparison to warfarin among nonvalvular AF patients in Saudi Arabia is largely unknown.

Methods

This was a single-center retrospective chart review of adult patients (≥18 years) with nonvalvular AF who were treated with warfarin or rivaroxaban for at least 12 months. Patients with mitral valve stenosis were excluded from the study. Multiple logistic regression was conducted to examine the risk of hospitalization and mortality as a composite outcome, and all annual healthcare costs were captured. Inverse probability treatment weighting with bootstrapping was conducted to determine the mean costs and effectiveness rates.

Results

Two-hundred and twenty-six patients (142 on rivaroxaban and 84 on warfarin) met the inclusion criteria and were included in the analysis. Most of the patients were females (65.91 %), had diabetes (50.57 %) and hypertension (73.76 %), and with a mean age of 68.95 ± 12.55 years. No significant difference in the odds of the composite outcome for rivaroxaban versus warfarin was found (OR = 0.785, 95 % CI = [0.427-1.446], p = 0.443). Rivaroxaban resulted in a mean annual cost saving of $13,260.79 with an 87.65 % confidence level that it would be more effective than warfarin with a mean difference in effectiveness rate of 0.168 % (95 % CI [-5.210-18.36]).

Conclusion

Rivaroxaban was associated with lower direct medical costs and non-inferior effectiveness among nonvalvular AF patients in comparison to warfarin.

Economic evaluation of direct oral anticoagulants (DOACs) versus vitamin K antagonists (VKAs) for stroke prevention in patients with atrial fibrillation: a systematic review and meta-analysis

OBJECTIVES

To assess cost-effectiveness of direct oral anticoagulants (DOACs) compared with vitamin K antagonists (VKAs) for stroke prevention in atrial fibrillation (AF) by pooling incremental net benefits (INBs).

DESIGN

Systematic review and meta-analysis.

SETTING

We searched PubMed, Scopus and Centre for Evaluation of Value and Risks in Health Registry from inception to December 2019.

PARTICIPANTS

Patients with AF.

MAIN OUTCOME MEASURES

The INB was defined as a difference of incremental effectiveness multiplied by willing to pay threshold minus the incremental cost; a positive INB indicated favour treatment. These INBs were pooled (stratified by level of country income, perspective, time-horizon, model types) with a random-effects model if heterogeneity existed, otherwise a fixed effects model was applied. Heterogeneity was assessed using Q test and I² statistic. Risk of bias was assessed using the economic evaluations bias (ECOBIAS) checklist.

RESULTS

A total of 100 eligible economic evaluation studies (224 comparisons) were included. For high-income countries (HICs) from a third-party payer (TPP) perspective, the pooled INBs for DOAC versus VKA pairs were significantly cost-effective with INBs (95% CI) of $6632 ($2961.67 to $10 303.72; I²=59.9%), $6353.24 ($4076.03 to $8630.45; I²=0%), $7664.58 ($2979.79 to $12 349.37; I²=0%) and $8573.07 ($1877.05 to $15 269.09; I²=0%) for dabigatran, apixaban, rivaroxaban and edoxaban relative to VKA, respectively but only dabigatran was significantly cost-effective from societal perspective (SP) with an INB of $11 746.96 ($2429.34 to $21 064.59; I²=52.4%). The pooled INBs of all comparisons for upper-middle income countries (UMICs) were not significantly cost-effective. The ECOBIAS checklist indicated that risk of bias was mostly low for most items with the exception of five items which should be less influenced on pooling INBs.

CONCLUSIONS

Our meta-analysis provides comprehensive economic evidence that allows policy makers to generalise cost-effectiveness data to their local context. All DOACs may be cost-effective compared with VKA in HICs with TPP perspective. The pooling results produced moderate to high heterogeneity particularly in UMICs. Further studies are required to inform UMICs with SP.

PROSPERO REGISTERATION NUMBER

CRD 42019146610.

Patients’ time in therapeutic range on warfarin among atrial fibrillation patients in Warfarin Medication Therapy Adherence Clinic

BACKGROUND

The quality of warfarin therapy can be determined by the time in the therapeutic range (TTR) of international normalized ratio (INR). The estimated minimum TTR needed to achieve a benefit from warfarin therapy is ≥ 60%.

AIM

To determine TTR and the predictors of poor TTR among atrial fibrillation patients who receive warfarin therapy.

METHODS

A retrospective observational study was conducted at a cardiology referral center in Selangor, Malaysia. A total of 420 patients with atrial fibrillation and under follow-up at the pharmacist led Warfarin Medication Therapeutic Adherence Clinic between January 2014 and December 2018 were included. Patients’ clinical data, information related to warfarin therapy, and INR readings were traced through electronic Hospital Information system. A data collection form was used for data collection. The percentage of days when INR was within range was calculated using the Rosendaal method. The poor INR control category was defined as a TTR < 60%. Predictors for poor TTR were further determined by using logistic regression.

RESULTS

A total of 420 patients [54.0% male; mean age 65.7 (10.9) years] were included. The calculated mean and median TTR were 60.6% ± 20.6% and 64% (interquartile range 48%-75%), respectively. Of the included patients, 57.6% (n = 242) were in the good control category and 42.4% (n = 178) were in the poor control category. The annual calculated mean TTR between the year 2014 and 2018 ranged from 59.7% and 67.3%. A high HAS-BLED score of ≥ 3 was associated with poor TTR (adjusted odds ratio, 2.525; 95% confidence interval: 1.6-3.9, P < 0.001).

CONCLUSION

In our population, a high HAS-BLED score was associated with poor TTR. This could provide an important insight when initiating an oral anticoagulant for these patients. Patients with a high HAS-BLED score may obtain less benefit from warfarin therapy and should be considered for other available oral anticoagulants for maximum benefit.

Structural Changes of Sodium Warfarin in Tablets Affecting the Dissolution Profiles and Potential Safety of Generic Substitution

At present, the risk of generic substitutions in warfarin tablets is still being discussed. The aim of this study was to assess whether API interactions with commonly used excipients may affect the safety of generic replacement of warfarin sodium tablets. These interactions were observed during an accelerated stability study, and the effect of the warfarin solid phase (crystalline/amorphous form) as well as the API particle size distribution was studied. Commercial tablets and prepared tablets containing crystalline warfarin or amorphous warfarin were used. In addition, binary mixtures of warfarin with various excipients were prepared. The structural changes before and after the stability study were monitored by dissolution test in different media, solid-state NMR spectroscopy and Raman microscopy. During the stability study, the conversion of the sodium in warfarin to its acid form was demonstrated by some excipients (e.g., calcium phosphate). This change in the solid phase of warfarin leads to significant changes in dissolution, especially with the different particle sizes of the APIs in the tablet. Thus, the choice of suitable excipients and particle sizes are critical factors influencing the safety of generic warfarin sodium tablets.

The association between increasing oral anticoagulant prescribing and atrial fibrillation related stroke in Ireland

AIMS

Recent increases in the number of patients with atrial fibrillation (AF) prescribed oral anticoagulants (OAC) are evident in Ireland and internationally, largely due to the availability of direct oral anticoagulants (DOACs). This study aimed to determine the rate of stroke in the context of increasing anticoagulation utilisation, with a focus on AF-related ischaemic stroke (IS).

METHODS

Dispensing data for OACs were identified for the period 2010-2018 as well as hospital discharges for IS (2005-2018). Irish National Stroke Register data were used to elucidate the characteristics of patients with acute ischaemic stroke.

RESULTS

The number of patients prescribed OACs increased by 94% from 2010-2018 with a significant change from 2013 (β = 2.57, P = .038), associated with a large increase in the number of patients on DOACs. There was 3.3-fold increase in expenditure on OACs nationally from 2013 to 2018, of which 94% was DOAC related. Using the 2013 timepoint, ischaemic stroke rates until 2018 did not show a significant deviation from the previous trend (β = 0.00, P = .898). The percentage of AF-related ischaemic stroke was stable from 2013 to 2017 with a 4.5% decrease in 2018. The percentage of ischaemic stroke patients with previously diagnosed AF decreased from 2013 to 2018; however, there was an increase in the percentage of ischaemic strokes while on OAC in this cohort.

CONCLUSION

Large increases in OAC utilisation have not resulted in changes in ischaemic stroke rates at a national level. The percentage of ischaemic strokes with a previous diagnosis of AF has decreased indicating a possible benefit from greater OAC utilisation. However, the percentage presenting with an ischaemic stroke while on OAC treatment is increasing. The increase in patients presenting with stroke while treated with OAC may largely reflect the national increase in patients prescribed DOACs but the findings raise concerns about treatment failures. The real-world effectiveness of DOACs requires further examination.

Cost saving analysis of specialized, eHealth-based management of patients receiving oral anticoagulation therapy: Results from the thrombEVAL study

To evaluate the cost-saving of a specialized, eHealth-based management service (CS) in comparison to regular medical care (RMC) for the management of patients receiving oral anticoagulation (OAC) therapy. Costs of hospitalization were derived via diagnosis-related groups which comprise diagnoses (ICD-10) and operation and procedure classification system (OPS), which resulted in OAC-related (i.e. bleeding/ thromboembolic events) and non-OAC-related costs for both cohorts. Cost for anticoagulation management comprised INR-testing, personnel, and technical support. In total, 705 patients were managed by CS and 1490 patients received RMC. The number of hospital stays was significantly lower in the CS cohort compared to RMC (CS: 23.4/100 py; RMC: 68.7/100 py); with the most pronounced difference in OAC-related admissions (CS: 2.8/100 py; RMC: 13.3/100 py). Total costs for anticoagulation management amounted to 101 EUR/py in RMC and 311 EUR/py in CS, whereas hospitalization costs were 3261 [IQR 2857-3689] EUR/py in RMC and 683 [504-874] EUR/py in CS. This resulted in an overall cost saving 2368 EUR/py favoring the CS. The lower frequency of adverse events in anticoagulated patients managed by the telemedicine-based CS compared to RMC translated into a substantial cost-saving, despite higher costs for the specialized management of patients.Trial registration: ClinicalTrials.gov, unique identifier NCT01809015, March 8, 2013.

Cost-Effectiveness of Extended and One-Time Screening Versus No Screening for Non-Valvular Atrial Fibrillation in the USA

BACKGROUND

There is limited evidence on the clinical and cost benefits of screening for atrial fibrillation (AF) with electrocardiogram (ECG) in asymptomatic adults.

METHODS

We adapted a previously published Markov model to evaluate the clinical and economic impact of one-time screening for non-valvular AF (NVAF) with a single 12-lead ECG and a 14-day extended screening with a hand-held ECG device (Zenicor single-lead ECG, Z14) compared with no screening. Clinical events considered included ischemic stroke, systemic embolism, major bleeds, myocardial infarction, and death. Epidemiology and effectiveness data for extended screening were from the STROKESTOP study. Risks of clinical events in NVAF patients were derived from ARISTOTLE. Analyses were conducted from the perspective of a third-party payer, considering a population with undiagnosed NVAF, aged 75 years in the USA. Costs and utilities were discounted at a 3% annual rate. Parameter uncertainty was formally considered via deterministic and probabilistic sensitivity analyses (DSA and PSA). Structural uncertainty was assessed via scenario analyses.

RESULTS

In a hypothetical cohort of 10,000 patients followed over their lifetimes, the number of additional AF diagnoses was 54 with 12-lead ECG and 255 with Z14 compared with no screening. Both screening strategies led to better health outcomes (ischemic strokes avoided: ECG 12-lead, 9.8 and Z14, 42.2; quality-adjusted life-years gained: ECG 12-lead, 31 and Z14, 131). Extended screening and one-time screening were cost effective compared with no screening at a willingness-to-pay (WTP) threshold of $100,000 per QALY gained ($58,728/QALY with ECG 12-lead and $47,949/QALY with Z14 in 2016 US dollars). ICERs remained below $100,000 per QALY in all DSA, most PSA runs, and in all scenario analyses except for a scenario assuming low anticoagulation persistence.

CONCLUSIONS

Our analysis suggests that, screening the general population at age 75 years for NVAF is cost effective at a WTP threshold of $100,000. Both extended screening and one-time screening for NVAF are expected to provide health benefits at an acceptable cost.

Cost-effectiveness analysis of antihypertensive triple combination therapy among patients enrolled in a Medicare advantage plan

OBJECTIVE

To assess the cost-effectiveness of single pill fixed dose triple combination therapy vs. free triple combination therapy for the prevention of cardiovascular events among patients with hypertension.

METHODS

A Markov model with a five year cycle was constructed. Two decision models incorporating strict and more relaxed adherence definitions estimated quality adjusted life years (QALYs) and health-care costs for single pill fixed triple combination therapy vs. free-drug combination therapy.

RESULTS

When the strict adherence measurement criteria were applied, the total QALYs loss and cost/patient were 6.38 QALYs, $486,026.20 for the single pill triple combination therapy and 8.64 QALYs, $406,405.26 for the free combination therapy. ICER for single pill combination therapy compared to free combination therapy was 33,826.46/QALY. When the relaxed adherence measurement criteria were applied, the total QALYs loss and cost/patient were 8.09 QALYs, $493,404.26 for the single pill triple combination therapy and 8.76 QALYs, $436,415.14 for the free combination therapy. ICER for single pill combination compared with free combination therapy was 84,932.26.

CONCLUSION

This study suggested that single pill triple combination therapy was cost-effective in comparison with free combination therapy under a willingness to pay threshold of 50,000 when the strict adherence measurement criteria was applied.

Group-based Trajectory Models to Assess Quality of INR Control and Its Association With Clinical Outcomes

Supplemental Digital Content is available in the text.

The Time in Therapeutic Range (TTR) is the gold-standard measure used to assess the quality of oral anticoagulation with vitamin K antagonists. However, TTR is a static measure, and International Normalized Ratio (INR) control is a dynamic process. Group-based Trajectory Models (GBTM) can address this dynamic nature by classifying patients into different trajectories of INR control over time.

A systematic review of patient-reported outcomes associated with the use of direct-acting oral anticoagulants

AIMS

Patient-reported outcomes (PROs) are a distinctive method of evaluating patient response to health care or treatment. This systematic review aimed to analyse the impact of PROs in patients on direct oral anticoagulant (DOAC) treatment, prescribed for any indication (e.g. venous thromboembolism treatment or atrial fibrillation) using controlled trials (CT) and real-world observational studies (OS).

METHODS

A systematic search of articles was conducted according to PRISMA guidelines using databases, with the last update in November 2018. The Cochrane Collaboration tool for assessing bias in randomized CTs and the Newcastle-Ottawa Scale adapted for cross-sectional studies were used. Outcomes evaluated were related to health-related quality of life (HRQoL), satisfaction, adherence and compliance.

RESULTS

Twenty-one original studies (6 CT, 15 OS) were included. HRQoL was assessed by 6 (1 CT, 5 OS) studies and reported that HRQoL scores were similar in patients on DOACs and warfarin. Patients prescribed DOACs presented higher HRQoL scores which were attributed to lack of intense monitoring required compared with warfarin but this was not statistically significant. The majority of studies (5 CT, 9 OS) investigated patient-reported satisfaction, indicating greater satisfaction with DOACs with significantly lower burden and increased benefit scores for patients on DOACs. Patient-reported expectations, compliance and adherence were similar for patients on DOACs and warfarin.

CONCLUSION

Patients appear to prefer treatment with DOACs vs warfarin. This is shown by the higher quality of life, satisfaction and adherence described in the studies. However, heterogeneity in the analysed studies does not allow firm conclusions.

Anticoagulant plus antiplatelet therapy for atrial fibrillation : Cost-utility of combination therapy with non-vitamin K oral anticoagulants vs. warfarin

BACKGROUND

Emerging evidence indicates combination therapy with anticoagulants and antiplatelet agents for atrial fibrillation (AF) will be increasingly required. Numerous studies compare the efficacy and cost-effectiveness of anticoagulation alone in AF, i. e., non-vitamin K oral anticoagulants (NOACs) vs. warfarin. However, the addition of antiplatelet agents with their potential for decreasing thromboembolic stroke counter-balanced by an increased bleeding risk has received less attention. Thus, we evaluated the cost-utility of this combination therapy.

METHOD AND RESULTS

We obtained event estimates from our recent meta-analysis of four randomized clinical trials designed to compare NOACs with warfarin in patients with AF. We examined patient subgroups within each trial that received antiplatelet therapy in addition to anticoagulation. Utilities were derived from the literature and cost estimates from the German health-care system. A decision tree was constructed and populated with these parameters. We used a 1-year time horizon because combination therapy is not recommended beyond this time. We calculated the incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY). The derived ICER was 13,168.50 € per QALY. NOAC prices exerted considerable influence on the calculation. Nevertheless, there is potential for ICER shifts in favor of warfarin, e.g., if warfarin-mediated anticoagulation control is improved and thereby adverse events decrease. Conversely, if NOAC adherence decreases, adverse events could increase.

CONCLUSION

The derived ICER was 13,168.50 € per QALY, consistent with NOACs being cost-effective vs. warfarin when anticoagulation is used with antiplatelet agents. Nevertheless, country-, practice-, and patient-related factors influence the ICER. Our cost-utility calculation should be used a starting point for decision-making.

Comparing the Cost Effectiveness of Non-vitamin K Antagonist Oral Anticoagulants with Well-Managed Warfarin for Stroke Prevention in Atrial Fibrillation Patients at High Risk of Bleeding

BACKGROUND

Several studies have compared the cost effectiveness of non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin using results from clinical trials evaluating NOACs. However, the time in therapeutic range (TTR) of warfarin groups ranged across clinical trials, and all were below the therapeutic goal of 70%. We compared the cost effectiveness of edoxaban 60 mg, apixaban 5 mg, dabigatran 150 mg, dabigatran 110 mg, rivaroxaban 20 mg, and well-managed warfarin with a TTR of 70% in preventing stroke among patients with atrial fibrillation at high risk of bleeding.

METHODS

For the six treatments, we used a Markov state-transition model to quantify lifetime costs in $US and effectiveness in quality-adjusted life-years (QALYs). We simulated relative risk ratios of clinical events with each NOAC versus warfarin with a TTR of 70% using published regression models that predict how the incidence of thrombotic or hemorrhagic events changes for each unit change in TTR. We re-ran our analysis for two other estimates of TTR: 65 and 75%.

RESULTS

Treatment with edoxaban 60 mg cost $US127,520/QALY gained compared with warfarin with a TTR of 70% and cost $US41,860/QALY gained compared with warfarin with a TTR of 65%. However, warfarin with a TTR of 75% was more effective and less expensive than all NOACs. For three levels of TTR, apixaban 5 mg, dabigatran 150 mg, dabigatran 110 mg, and rivaroxaban 20 mg were dominated strategies.

CONCLUSIONS

The comparative cost effectiveness of edoxaban and warfarin is highly sensitive to TTR. At the $US100,000/QALY willingness-to-pay threshold, our results suggest that warfarin is the most cost-effective treatment for patients who can achieve a TTR of 70%.

Evaluation of bleeding in patients receiving direct oral anticoagulants

Direct oral anticoagulants (DOACs) are recognized by evidence-based treatment guidelines as the first-line option for the treatment of venous thromboembolism and prevention of stroke and systemic embolism in nonvalvular atrial fibrillation. As use of these anticoagulants has become favored over the past several years, reported bleeding-related adverse drug events with these agents has increased. In randomized clinical trials, all DOACs have a reduced risk for intracranial hemorrhage, while major and other bleeding results have varied among the agents compared to vitamin K antagonists. We have reviewed the bleeding incidence and severity from randomized and real-world data in patients receiving DOACs in an effort to provide the clinician with a critical review of bleeding and offer practical considerations for avoiding adverse events with these anticoagulants.

Cost-Effectiveness of Warfarin Medication Therapy Adherence Clinic versus Usual Medical Clinic at Kuala Lumpur Hospital

BACKGROUND

Systematic anticoagulation management clinic is recommended to manage patients on chronic warfarin therapy. In Malaysia, the service was introduced as warfarin medication therapy adherence clinic (WMTAC), which is managed by pharmacists with a physician advisory.

OBJECTIVES

To assess the cost-effectiveness of WMTAC in comparison with usual medical clinic (UMC), which is managed by medical officers in Kuala Lumpur Hospital, a tertiary referral hospital in Malaysia.

METHODS

Data from a 6-month retrospective cohort study comparing the two clinics and the mean percentages of time in the therapeutic range for the patients were used to estimate the cost-effectiveness. The mean clinic costs were estimated using the time-motion study. A Markov model with a 6-monthly cycle was used to simulate lifetime cost-effectiveness from the perspective of the health care service provider. The base-case analysis assumed a cohort of patients with atrial fibrillation, 57 years of age with comorbid illnesses. The transition probabilities of these clinic outcomes were obtained from a literature search. Future costs and effectiveness were discounted by 3% to convert to present values. All costs were in Malaysian ringgit standardized for the year 2007.

RESULTS

The mean 6-month treatment cost was lower for the WMTAC, which was significantly lower (P < 0.001). The UMC was found to be dominated by the WMTAC for both intermediate and lifetime analyses. The sensitivity analysis showed that clinic consultation costs had a major impact on the cost-effectiveness analysis.

CONCLUSIONS

WMTAC is a more cost-effective option than UMC in Kuala Lumpur Hospital.

e-Health-based management of patients receiving oral anticoagulation therapy: results from the observational thrombEVAL study

Essentials e-Health based health care by an expert centre may advance management of oral anticoagulation. Outcome of patients was compared between an e-health based coagulation service and regular care. Patients in the coagulation service cohort experienced a significantly better clinical outcome. Lower risk for adverse events was related to anticoagulation-specific and non-specific outcome.

SUMMARY

Background Management of oral anticoagulation (OAC) therapy is essential to minimize adverse events in patients receiving vitamin K-antagonists (VKAs). Data on the effect of e-health-based anticoagulation management systems on the clinical outcome of OAC patients are limited. Objectives To compare the clinical outcome of OAC patients managed by an e-health-based coagulation service (CS) with that of patients receiving regular medical care (RMC). Methods The prospective multicenter cohort study thrombEVAL (NCT01809015) comprised 1558 individuals receiving RMC and 760 individuals managed by a CS. Independent study monitoring and adjudication of endpoints by an independent review panel were implemented. Results The primary study endpoint (composite of thromboembolism, clinically relevant bleeding and death) occurred in 15.7 per 100 patient-years (py) with RMC and in 7.0 per 100 py with the CS (rate ratio [RR], 2.3; 95% confidence interval [CI], 1.7-3.1). Rates for major and clinically relevant bleeding were higher with RMC than with the CS: 6.8 vs. 2.6 and 10.1 vs. 3.6 per 100 py, respectively. Thromboembolic events showed an RR of 1.5 (95% CI, 0.8-2.6) comparing RMC with the CS. Hospitalization (RR, 2.6; 95% CI, 2.3-3.0) and all-cause mortality (RR, 4.6; 95% CI, 2.8-7.7) were markedly more frequent with RMC. In Cox regression analysis with adjustment for age, sex, cardiovascular risk factors, comorbidities, treatment characteristics and sociodemographic status, hazard ratios (HR) for the primary endpoint (HR, 2.2; 95% CI, 1.5-3.4), clinically relevant bleeding (HR, 3.1; 95% CI, 1.7-5.5), hospitalization (HR, 2.2; 95% CI, 1.8-2.8) and all-cause mortality (HR, 5.6; 95% CI, 2.9-11.0) favored CS treatment. Conclusions In this study, e-health-based management of OAC therapy was associated with a lower frequency of OAC-specific and non-specific adverse events.

Causes of death in atrial fibrillation: Challenges and opportunities

Atrial fibrillation (AF) is an age-related arrhythmia associated with several co-morbidities and significant mortality. Most AF patients are in need of anticoagulation due to increased risk of stroke. Despite anticoagulation, AF patients still have a significant risk of death (about 5%/y). Approximately half of deaths in AF are due to heart-related causes (i.e., sudden death, heart failure, and myocardial infarction), one-third of deaths are due to non-vascular causes (i.e., cancer, respiratory diseases, and infections) and the remaining AF patients die from stroke or hemorrhage (about 6% each), or other causes. This review describes current situations related to causes of death in AF, the challenges in the management of AF (e.g., frequent presence of cardiovascular risk factors and co-morbidities, physicians adherence to clinical guidelines and patients adherence to cardiovascular medications in AF) as well as the opportunities for intervention.

Optimal Reversal of Novel Anticoagulants in Trauma

The incidence of patients with trauma on novel oral anticoagulants (NOACs) for the treatment of thromboembolic disorders is increasing. In severe bleeding or hemorrhage into critical spaces, urgent reversal of this underlying pharmacologic coagulopathy becomes paramount. Optimal reversal strategy for commonly used NOACs is still evolving. Basic tenets of evaluation of patients with trauma and resuscitation remain the same. Clinical outcomes data in bleeding human patients with trauma are lacking, but are needed to establish efficacy and safety in these treatments. This article summarizes the available evidence and provides the optimal reversal strategy for bleeding patients with trauma on NOACs.

Results of a Regional Effort to Improve Warfarin Management

BACKGROUND

Improved anticoagulation control with warfarin reduces adverse events and represents a target for quality improvement. No previous study has described an effort to improve anticoagulation control across a health system.

OBJECTIVE

To describe the results of an effort to improve anticoagulation control in the New England region of the Veterans Health Administration (VA).

METHODS

Our intervention encompassed 8 VA sites managing warfarin for more than 5000 patients in New England (Veterans Integrated Service Network 1 [VISN 1]). We provided sites with a system to measure processes of care, along with targeted audit and feedback. We focused on processes of care associated with site-level anticoagulation control, including prompt follow-up after out-of-range international normalized ratio (INR) values, minimizing loss to follow-up, and use of guideline-concordant INR target ranges. We used a difference-in-differences (DID) model to examine changes in anticoagulation control, measured as percentage time in therapeutic range (TTR), as well as process measures and compared VISN 1 sites with 116 VA sites located outside VISN 1.

RESULTS

VISN 1 sites improved on TTR, our main indicator of quality, from 66.4% to 69.2%, whereas sites outside VISN 1 improved from 65.9% to 66.4% (DID 2.3%, P < 0.001). Improvement in TTR correlated strongly with the extent of improvement on process-of-care measures, which varied widely across VISN 1 sites.

CONCLUSIONS

A regional quality improvement initiative, using performance measurement with audit and feedback, improved TTR by 2.3% more than control sites, which is a clinically important difference. Improving relevant processes of care can improve outcomes for patients receiving warfarin.

Quality of pharmacoeconomic research in China: A systematic review

BACKGROUND

The number of pharmacoeconomic publications in the literature from China has risen rapidly, but the quality of pharmacoeconomic publications from China has not been analyzed.

OBJECTIVES

This study aims to identify all recent pharmacoeconomic publications from China, to critically appraise the reporting quality, and to summarize the results.

METHODS

Four databases (PubMed, Web of Science, Medline, and EmBase) were searched for original articles published up to December 31, 2014. The Consolidated Health Economic Evaluation Reporting Standards statement including 24 items was used to assess the quality of reporting of these articles.

RESULTS

Of 1046 articles identified, 32 studies fulfilled the inclusion criteria. They were published in 23 different journals. Quality of reporting varied between studies, with an average score of 18.7 (SD = 4.33) out of 24 (range 9-23.5). There was an increasing trend of pharmacoeconomic publications and reporting quality over years from 2003 to 2014. According to the Consolidated Health Economic Evaluation Reporting Standards, the reporting quality for the items including "title," "comparators of method," and "measurement of effectiveness" are quite low, with less than 50% of studies fully satisfying these reporting standards. In contrast, reporting was good for the items including "introduction," "study perspective," "choice of health outcomes," "study parameters," "characterizing heterogeneity," and "discussion," with more than 75% of the articles satisfying these reporting criteria. The remaining items fell in between these 2 extremes, with 50% to 75% of studies satisfying these criteria.

CONCLUSION

Our study suggests the need for improvement in a number of reporting criteria. But the criteria for which reporting quality was low seem to be limitations that would be straightforward to correct in future studies.

Comparison of the Abilities of Summary Measures of International Normalized Ratio Control to Predict Clinically Relevant Bleeding

BACKGROUND

Limited research has compared the measures of summarizing international normalized ratio (INR) control over time. Measures that are more predictive of patient outcomes would be preferred as would those that are easier to calculate and understand.

METHODS AND RESULTS

We examined 676 patients who received long-term warfarin therapy to treat atrial fibrillation: 125 patients who experienced major hemorrhage and 551 matched controls who did not. Patient INR control was characterized using various measures, from simple (proportion of INR values in range) to complex (eg, area under the curve above target range, squared) measures. Conditional logistic regression was used to examine the ability of each measure to predict the outcome of clinically relevant bleeding across quintiles of control. All measures were associated with clinically relevant bleeding to some extent: patients with the poorest control had significantly more bleeding events compared with patients with the best control. The measure most strongly associated with bleeding was a combination of percent time in therapeutic range and INR variability (odds ratio of 4.34, comparing the lowest to the highest quintiles of control). The strongest single predictor was INR variability, followed closely by time in therapeutic range. More computationally complex measures, which had been expected to perform better, were not so strongly associated with bleeding.

CONCLUSIONS

INR variability was the most strongly associated predictor of clinically relevant bleeding followed closely by time in therapeutic range. Using both measures together had an even stronger association. These findings support continued use of INR variability, time in therapeutic range, or both for research and quality assurance efforts.

Evaluation of Time in Therapeutic Range (TTR) in Patients with Non-Valvular Atrial Fibrillation Receiving Treatment with Warfarin in Tehran, Iran: A Cross-Sectional Study

INTRODUCTION

Anticoagulant control is assessed by Time in Therapeutic Range (TTR). For a given patient, TTR is defined as the duration of time in which the patient's International Normalized Ratio (INR) values were within a desired range.

AIM

To assess TTR in patients receiving treatment with warfarin for non-valvular atrial fibrillation at a referral center for cardiovascular diseases in Tehran, Iran.

MATERIALS AND METHOD

Over 6 months, we enrolled eligible patients presenting to Shaheed Rajaie Hospital in Tehran for regular INR testing. Demographic data, medical history, and current medications were determined for all participants. TTR was assessed by the Rosendaal method.

RESULTS

A total of 470 patients (mean age 58.0±14.2 years, 60.2% women) underwent 1450 INR measurements. The mean TTR was calculated as 54.9±11.9%. Of the sample patients, 37.3% were in the good control category (TTR > 70%), 24.6% were in the intermediate category (50% < TTR < 70%), and 38.1% were in the poor control category (TTR < 50%). The number of current medications above four was a significant predictor of poor control (OR = 2.06; 95% CI, 1.87, 2.23). The mean TTR of the studied patients (54.9%) was below the good control range.

CONCLUSION

The quality of anticoagulant therapy with warfarin in Iranian patients was poorer than that reported in European countries. Based on these results, research considering the causes of poor TTR among Iranian patients is recommended.

Cost-effectiveness of edoxaban versus rivaroxaban for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF) in the US

BACKGROUND

Understanding the value of new anticoagulation therapies compared with existing therapies is of paramount importance in today's cost-conscious and efficiency-driven health care environment. Edoxaban and rivaroxaban for stroke prevention in nonvalvular atrial fibrillation (NVAF) patients with CHADS2 scores ≥2 have been evaluated in pivotal trials versus warfarin. The relative value of edoxaban versus rivaroxaban would be of interest to health care stakeholders and patients who prefer a once-daily treatment option for long-term stroke prevention in NVAF.

OBJECTIVE

To evaluate the relative cost-effectiveness of two once-daily regimens of novel oral anticoagulation therapy - edoxaban (60 mg/30 mg dose-reduced) versus rivaroxaban (20 mg/15 mg dose-reduced) - for stroke prevention in NVAF patients from a US health-plan perspective.

MATERIALS AND METHODS

A Markov model simulated lifetime risk and treatment of stroke, systemic embolism, major bleeding, clinically relevant nonmajor bleeding, myocardial infarction, and death in NVAF patients treated with edoxaban or rivaroxaban. Efficacy and safety data were derived from a network meta-analysis that utilized data from patients enrolled in ENGAGE AF-TIMI 48 and ROCKET-AF. Health care cost and utility data were obtained from published sources. Incremental cost-effectiveness ratios of $150,000 per quality-adjusted life year (QALY) gained were used as thresholds for "highly cost-effective", "cost-effective", and "not cost-effective" treatment options, respectively, as per American Heart Association/American College of Cardiology guidelines.

RESULTS

Edoxaban was dominant relative to rivaroxaban, such that it was associated with lower total health care costs and better effectiveness in terms of QALYs in the base-case analysis. Results were supported by probabilistic sensitivity analyses that showed edoxaban as either dominant or a highly cost-effective alternative (incremental cost-effectiveness ratio <$50,000) to rivaroxaban in 88.4% of 10,000 simulations.

CONCLUSION

Results of this study showed that the once-daily edoxaban (60 mg/30 mg dose-reduced) regimen is a cost-saving or highly cost-effective treatment relative to rivaroxaban (20 mg/15 mg dose-reduced) for stroke prevention in NVAF patients with CHADS2 ≥2.

Cost-Effectiveness of Novel Oral Anticoagulants for Stroke Prevention in Non-Valvular Atrial Fibrillation

Recently, novel oral anticoagulants (NOACs) have been approved for stroke prevention in patients with atrial fibrillation (AF). Although these agents overcome some disadvantages of warfarin, they are associated with increased costs. In this review, we will provide an overview of the cost-effectiveness of NOACs for stroke prevention in AF. Our comments and conclusions are limited to studies directly comparing all available NOACs within the same framework. The available cost-effectiveness analyses suggest that NOACs are cost-effective compared to warfarin, with apixaban likely being most favorable. However, significant limitations in these models are present and should be appreciated when interpreting their results.

Anticoagulation Control in Swiss Primary Care: Time in Therapeutic Range Percentages Exceed Benchmarks of Phase III Trials

BACKGROUND

In randomized controlled trials, non-vitamin K antagonist oral anticoagulants (NOACs) demonstrated noninferiority to vitamin K antagonists (VKAs) in patients who spent limited time in therapeutic range (TTR). In real-life patients, TTR is known to vary significantly across countries and health-care settings.

OBJECTIVE

We aim to evaluate the quality of VKA treatment in Swiss primary care (PC) by comparing patients' median TTR to levels achieved in the phase III NOAC trials RE-LY, ROCKET-AF, ARISTOTLE, and ENGAGE-AF-TIMI 48. Patient characteristics affecting TTR control shall be estimated.

METHODS

This is a retrospective longitudinal study in Swiss PC patients receiving VKA for ≥6 months. We identified patients from the PC research database FIRE (Family medicine International Classification of Primary Care Research using Electronic medical records) and calculated TTR according to Rosendaal formula. Comparative data from NOAC trials were retrieved from medical literature. Linear regression models were used to assess predictors of TTR.

RESULTS

Primary care encounters of 215 patients were analyzed. Like in the NOAC trials, median observation period was 2.2 years, but patients were older (67.9% vs 38% ≥75 years) and differed in terms of concomitant diseases and drugs. Median TTR was 75% (65% in the NOAC trials). Female sex was independently associated with a lower TTR and significantly modified by increasing age.

CONCLUSION

Practitioners should consider that patients in NOAC trials are only partly representative of PC patients, particularly in terms of TTR control. Only a minority of the observed patients would require a therapy switch to NOACs due to inadequate TTR. Further research is needed in order to identify specific features of care management that are associated with these outcomes.

Cost-effectiveness of edoxaban vs warfarin in patients with atrial fibrillation based on results of the ENGAGE AF-TIMI 48 trial

BACKGROUND

In 21,105 patients with atrial fibrillation (AF), the ENGAGE AF-TIMI 48 trial demonstrated that both higher dose (60mg/30mg dose reduced) and lower dose (30mg/15mg dose reduced) once-daily regimens of edoxaban were non-inferior to warfarin for the prevention of stroke or systemic embolism (SE), with significantly lower rates of bleeding and cardiovascular death. Higher dose edoxaban was associated with a greater reduction in the risk of ischemic stroke than lower dose edoxaban, and the FDA approved higher dose edoxaban in patients with creatinine clearance ≤95mL/min. This study evaluated the economic value of higher dose edoxaban vs warfarin based on data from patients in ENGAGE within the FDA-approved population.

METHODS

We assessed the cost-effectiveness of edoxaban vs warfarin over a lifetime horizon from the US healthcare system perspective using a Markov model based on a combination of ENGAGE AF-TIMI 48 trial data, US life tables, and published literature on the costs and long-term outcomes of non-fatal cardiovascular and bleeding events. Data from the ENGAGE AF-TIMI 48 trial were used to calculate age-adjusted event rates for warfarin and hazard ratios (HRs) for the relative impact of edoxaban on embolic and bleeding complications. Based on the wholesale acquisition price, edoxaban and warfarin were assumed to cost $9.24 and $0.36/day, respectively.

RESULTS

For edoxaban vs warfarin, lifetime incremental costs and QALYs were $16,384 and 0.444, respectively, yielding an incremental cost-effectiveness ratio (ICER) of $36,862/QALY gained, using data from patients with creatinine clearance ≤95mL/min in ENGAGE AF-TIMI 48. ICERs were more favorable for patients without compared to those with prior warfarin use; ICERs differed minimally by CHADS2 score.

CONCLUSIONS

Despite its higher acquisition cost, edoxaban is an economically attractive alternative to warfarin for the prevention of stroke and SE in patients with atrial fibrillation and creatinine clearance ≤95mL/min. These results were robust to variation of key model parameters, including assumptions regarding the cost and quality-of-life impact of stroke and bleeding events, and were favorable across both CHADS2 score stroke-risk categories.

Time to Cost-Effectiveness Following Stroke Reduction Strategies in AF: Warfarin Versus NOACs Versus LAA Closure

BACKGROUND

Left atrial appendage closure (LAAC) and nonwarfarin oral anticoagulants (NOACs) have emerged as safe and effective alternatives to warfarin for stroke prophylaxis in patients with nonvalvular atrial fibrillation (AF).

OBJECTIVES

This analysis assessed the cost-effectiveness of warfarin, NOACs, and LAAC with the Watchman device (Boston Scientific, Marlborough, Massachusetts) for stroke risk reduction in patients with nonvalvular AF at multiple time points over a lifetime horizon.

METHODS

A Markov model was developed to assess the cost-effectiveness of LAAC, NOACs, and warfarin from the perspective of the Centers for Medicare & Medicaid Services over a lifetime (20-year) horizon. Patients were 70 years of age and at moderate risk for stroke and bleeding. Clinical event rates, stroke outcomes, and quality of life information were drawn predominantly from PROTECT AF (Watchman Left Atrial Appendage System for Embolic Protection in Patients with Atrial Fibrillation) 4-year data and meta-analyses of warfarin and NOACs. Costs for stroke risk reduction therapies, treatment of associated acute events, and long-term care following disabling stroke were presented in 2015 U.S. dollars.

RESULTS

Relative to warfarin, LAAC was cost-effective at 7 years ($42,994/quality-adjusted life-years [QALY]), and NOACs were cost-effective at 16 years ($48,446/QALY). LAAC was dominant over NOACs by year 5 and warfarin by year 10. At 10 years, LAAC provided more QALYs than warfarin and NOACs (5.855 vs. 5.601 vs. 5.751, respectively). In sensitivity analyses, LAAC remained cost-effective relative to warfarin ($41,470/QALY at 11 years) and NOACs ($21,964/QALY at 10 years), even if procedure costs were doubled.

CONCLUSIONS

Both NOACs and LAAC with the Watchman device were cost-effective relative to warfarin, but LAAC was also found to be cost-effective and to offer better value relative to NOACs. The results of this analysis should be considered when formulating policy and practice guidelines for stroke prevention in AF.

Sterile pyuria: a forgotten entity

Sterile pyuria is a common entity. Yet there are no guidelines to address this issue. We have conducted a systematic review over 20 years and reviewed the results. Guidelines for assessment, diagnosis and management are developed based on these results.

Plasma Exchange for Urgent Apixaban Reversal in a Case of Hemorrhagic Tamponade after Pacemaker Implantation

We report the case of an 82-year-old man in whom hemorrhagic pericardial effusion occurred one week after pacemaker implantation, while he was taking apixaban. Few therapies exist for reversing the anti-Xa effect of apixaban. To reverse anticoagulation, our patient underwent plasma exchange, which facilitated pericardiocentesis and prevented possible surgical intervention. To our knowledge, this is the first report of the use of plasmapheresis to reverse the anticoagulant effect of apixaban.

Universal versus genotype-guided use of direct oral anticoagulants in atrial fibrillation patients: a decision analysis

AIM

This study aims to compare clinical and economic outcomes of CYP2C9 and VKORC1 genotype-guided (PG-DOAC) versus universal use of direct oral anticoagulant (DOAC) for stroke prevention in patients with atrial fibrillation (AF).

METHODS

Outcomes of oral anticoagulation therapy were simulated using life-long Markov modeling. In PG-DOAC, patients with genotype of high or low warfarin sensitivity were treated with DOAC, and patients with normal warfarin sensitivity genotype received warfarin.

RESULTS

Expected quality-adjusted life-years (QALYs) and cost of DOAC were higher than PG-DOAC. Incremental cost per QALY (ICER) of DOAC versus PG-DOAC was 314,129 USD/QALY, exceeding willingness-to-pay threshold (50,000 USD/QALY).

CONCLUSION

Using individual genotype to guide the use of DOAC versus warfarin appears to be the preferred strategy.

Pharmacology of antithrombotic drugs: an assessment of oral antiplatelet and anticoagulant treatments

Antithrombotic drugs, which include antiplatelet and anticoagulant therapies, prevent and treat many cardiovascular disorders and, as such, are some of the most commonly prescribed drugs worldwide. The first drugs designed to inhibit platelets or coagulation factors, such as the antiplatelet clopidogrel and the anticoagulant warfarin, significantly reduced the risk of thrombotic events at the cost of increased bleeding in patients. However, both clopidogrel and warfarin have some pharmacological limitations including interpatient variability in antithrombotic effects in part due to the metabolism, interactions (eg, drug, environment, and genetic), or targets of the drugs. Increased knowledge of the pharmacology of antithrombotic drugs and the mechanisms underlying thrombosis has led to the development of newer drugs with faster onset of action, fewer interactions, and less interpatient variability in their antithrombotic effects than previous antithrombotic drugs. Treatment options now include the next-generation antiplatelet drugs prasugrel and ticagrelor, and, in terms of anticoagulants, inhibitors that directly target factor IIa (dabigatran) or Xa (rivaroxaban, apixaban, edoxaban) are available. In this Series paper we review the pharmacological properties of these most commonly used oral antithrombotic drugs, and explore the development of antiplatelet and anticoagulant therapies.

A Decision Analysis of Percutaneous Left Atrial Appendage Occlusion Relative to Novel and Traditional Oral Anticoagulation for Stroke Prevention in Patients with New-Onset Atrial Fibrillation

Background. Percutaneous left atrial appendage occlusion (LAAO) is a nonpharmacologic approach for stroke prevention in nonvalvular atrial fibrillation (NVAF). No direct comparisons to novel oral anticoagulants (OACs) exists, limiting decision making on the optimal strategy for stroke prevention in NVAF patients. Addressing this gap in knowledge is timely given the recent debate by the US Food and Drug Administration regarding the effectiveness of LAAO. Objective. To assess the cost-effectiveness of LAAO and novel OACs relative to warfarin in patients with new-onset NVAF without contraindications to OAC. Design. A cost-utility analysis using a patient-level Markov micro-simulation decision analytic model was undertaken to determine the lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) of LAAO and all novel OACs relative to warfarin. Effectiveness and utility data were obtained from the published literature and cost from the Ontario Drug Benefits Formulary and Case Costing Initiative. Results. Warfarin had the lowest discounted QALY (5.13 QALYs), followed by dabigatran (5.18 QALYs), rivaroxaban and LAAO (5.21 QALYs), and apixaban (5.25 QALYs). The average discounted lifetime costs were $15 776 for warfarin, $18 280 for rivaroxaban, $19 156 for apixaban, $20 794 for dabigatran, and $21 789 for LAAO. Apixaban dominated dabigatran and LAAO and demonstrated extended dominance over rivaroxaban. The ICER for apixaban relative to warfarin was $28 167/QALY. Apixaban was preferred in 40.2% of simulations at a willingness-to-pay threshold of $50 000/QALY. Limitations. Assumptions regarding clinical and methodological differences between published studies of each therapy were minimized. Conclusions. Apixaban is the most cost-effective therapy for stroke prevention in patients with new-onset NVAF without contraindications to OAC. Uncertainty around this conclusion exists, highlighting the need for further research.

Evaluation of time in therapeutic range in anticoagulated patients: a single-center, retrospective, observational study

Background

The percentage of time during which the patients have the INR within the target values (i.e. Time in Therapeutic Range [TTR]) is a measure of anticoagulation quality with Vitamin K Antagonists (VKA). To evaluate the quality of anticoagulation using TTR according to the Rosendaal method, we performed an observational, retrospective study. We included all outpatients who attended the cardiology anticoagulation clinic of a Portuguese hospital (2011–2013), whose target INR was 2.0-3.0.

Results

377 VKA-treated patients were evaluated. Of these, 72.4% had non-valvular atrial fibrillation. Patients were followed for a mean period of 471 days. The mean TTR was 60.3% (SD 19.3%) and 44.3% of the patients had a mean TTR < 60%. Patients were at high risk of bleeding (INR > 4.5) and at high thrombotic risk (INR < 1.5) during, respectively, 1.7% and 4.7% of the time.

Conclusions

Anticoagulation control needs to be improved. These results are informative for all stakeholders: patients, health care professionals, and policymakers.

Balancing ischaemia and bleeding risks with novel oral anticoagulants

Vitamin K antagonists (VKAs) have long been the standard of care for treatment of venous thromboembolism (VTE), and thromboprophylaxis in atrial fibrillation (AF). Despite their efficacy, their use requires frequent monitoring and is complicated by drug-drug interactions and the need to maintain a narrow therapeutic window. Since 2009, novel oral anticoagulants (NOACs), including the direct thrombin inhibitor dabigatran and the direct factor Xa inhibitors apixaban, edoxaban, and rivaroxaban, have become alternative options to VKAs owing to their predictable and safe pharmacological profiles. The overall clinical effect of these drugs, which is a balance between ischaemic benefit and bleeding harm, varies according to the clinical scenario. As adjunctive therapy to dual antiplatelet therapy in patients with acute coronary syndrome, NOACs are associated with incremental bleeding risks and modest benefits. For treatment of VTE, NOACs have a safer profile than VKAs and a similar efficacy. In thromboprophylaxis in AF, NOACs are associated with the greatest benefits by reducing both ischaemic events and haemorrhagic complications and might reduce mortality compared with VKAs. The role of NOACs continues to evolve as these drugs are evaluated in different patient populations, including those with renal impairment or with AF and undergoing percutaneous coronary intervention.

Antimicrobial stewardship programs - cost-minimizing or cost-effective?

Antimicrobial stewardship programs (ASPs) are aimed to improve patient care and health care outcomes. It is encouraging to find ASP interventions to be cost-saving in many cost-minimization analyses in literature. Nevertheless, the cost-effectiveness of ASP interventions, measured in cost per quality-adjusted life-years, is less well-established. This Editorial aims to explore the barriers in assessing clinical effectiveness of ASPs and provide suggestions to conduct cost-effectiveness analysis of ASPs.

Defining time in therapeutic range for busy clinicians: frequency of dose changes is a good surrogate marker to identify patients with suboptimal anticoagulation with warfarin

INTRODUCTION

Patients on warfarin with sub-optimal time-in-therapeutic-range (TTR) are more likely to have adverse events. Target-specific oral anticoagulants (TSOACs) are approved and can be used as an alternative to warfarin for a number of indications. Further, the efficacy and safety profiles of the TSOACs compared to warfarin are more favourable when the TTR is ≤65% for certain indications.

OBJECTIVE

We aimed to determine simple, sensitive and specific diagnostic tools to identify TTR ≤ 65% during the initial three months of warfarin therapy.

METHODS

A cross-sectional study including patients newly initiated on warfarin without any interruption for three months was conducted. TTR was calculated using the Rosendaal method. Patients were stratified by TTR (≤ 65% or >65%). Number of INR measurements, dose changes and INR measurements of ≤ 1.7 or ≥ 4.0 were evaluated as potential diagnostic tools to identify TTR ≤ 65%.

RESULTS

670 patients were included. The most common indication for anticoagulation was venous thromboembolism. The mean TTR in the first three months was 68 ± 21% (Range: 10 to 100%). Three or more dose changes identified TTR ≤ 65% and demonstrated a sensitivity and specificity of 90% (95%CI 86 to 93%) and 56% (95%CI 51 to 61%), respectively. Three or more INR measurements of ≤ 1.7 during the initial three months of anticoagulation showed a sensitivity and specificity of 37% (95%CI 32 to 43%) and 98% (95%CI 96 to 99%), respectively.

CONCLUSION

Three or more dose changes and three or more INR measurements of ≤ 1.7 could identify patients with a TTR ≤ 65% in the first three months of warfarin therapy.

The association of health literacy with time in therapeutic range for patients on warfarin therapy

Patients on warfarin therapy need to achieve and maintain anticoagulation control in order to experience the benefits of treatment while minimizing bleeding risk. Low health literacy skills may hinder patients' ability to use and adhere to warfarin in a safe and effective manner. The authors conducted this study to evaluate the relationship between health literacy and anticoagulation control among patients on chronic warfarin therapy. Participants were recruited from 2 diverse anticoagulation clinics in North Carolina. Time in therapeutic range (TTR) for warfarin therapy was used as a measure of anticoagulation control. Health literacy was assessed using the short form of the Test of Functional Health Literacy in Adults (S-TOFHLA). Of the 198 study participants, 51% had limited health literacy (S-TOFHLA score of 0-90) and 33% had poor anticoagulation control (TTR<50%). Participants with limited health literacy were less likely to correctly answer warfarin-related knowledge questions. Limited health literacy was significantly associated with TTR<50% (adjusted odds ratio=2.34, 95% CI [1.01, 5.46]). Findings indicate that limited health literacy is associated with poor anticoagulation control for patients on warfarin therapy. Lack of medication understanding may hinder the safe and effective use of this narrow therapeutic index drug.