Cost-effectiveness of new oral anticoagulants compared with warfarin in preventing stroke and other cardiovascular events in patients with atrial fibrillation

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.

Cost Effectiveness of Strategies to Manage Atrial Fibrillation in Middle- and High-Income Countries: A Systematic Review

BACKGROUND

Atrial fibrillation (AF) remains the most common form of cardiac arrhythmia. Management of AF aims to reduce the risk of stroke, heart failure and premature mortality via rate or rhythm control. This study aimed to review the literature on the cost effectiveness of treatment strategies to manage AF among adults living in low-, middle- and high-income countries.

METHODS

We searched MEDLINE (OvidSp), Embase, Web of Science, Cochrane Library, EconLit and Google Scholar for relevant studies between September 2022 and November 2022. The search strategy involved medical subject headings or related text words. Data management and selection was performed using EndNote library. The titles and abstracts were screened followed by eligibility assessment of full texts. Selection, assessment of the risk of bias within the studies, and data extraction were conducted by two independent reviewers. The cost-effectiveness results were synthesised narratively. The analysis was performed using Microsoft Excel 365. The incremental cost effectiveness ratio for each study was adjusted to 2021 USD values.

RESULTS

Fifty studies were included in the analysis after selection and risk of bias assessment. In high-income countries, apixaban was predominantly cost effective for stroke prevention in patients at low and moderate risk of stroke, while left atrial appendage closure (LAAC) was cost effective in patients at high risk of stroke. Propranolol was the cost-effective choice for rate control, while catheter ablation and the convergent procedure were cost-effective strategies in patients with paroxysmal and persistent AF, respectively. Among the anti-arrhythmic drugs, sotalol was the cost-effective strategy for rhythm control. In middle-income countries, apixaban was the cost-effective choice for stroke prevention in patients at low and moderate risk of stroke while high-dose edoxaban was cost effective in patients at high risk of stroke. Radiofrequency catheter ablation was the cost-effective option in rhythm control. No data were available for low-income countries.

CONCLUSION

This systematic review has shown that there are several cost-effective strategies to manage AF in different resource settings. However, the decision to use any strategy should be guided by objective clinical and economic evidence supported by sound clinical judgement.

REGISTRATION

CRD42022360590.

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

RATIONALE

Atrial fibrillation (AF) is associated with an increased risk of thromboembolism. This risk is currently assessed with scoring systems based on clinical characteristics. However, these tools have limited prognostic performance. Circulating biomarkers are proposed for improved prediction of major clinical events and individualization of treatments in patients with AF.

OBJECTIVE

The aim was to assess the cost-effectiveness of precision medicine (PM), i.e., the use of combined biomarkers and clinical variables, in comparison to standard of care (SOC) for risk stratification in a hypothetical cohort of AF patients at risk of stroke.

METHODS

A Markov cohort model was developed to evaluate the costs and quality-adjusted life-years (QALYs) of PM compared to SOC, over 20 years using a Canadian healthcare system perspective.

RESULTS

PM decreased the mean per-patient overall costs by 7% ($94,932 vs $102,057 [Canadian dollars], respectively) and increased the QALYs by 12% (8.77 vs 7.68 QALYs, respectively). The calculated incremental cost-effectiveness ratio was negative, indicating that PM is an economically dominant strategy. These results were robust to one-way and probabilistic sensitivity analyses.

CONCLUSION

PM compared to SOC is economically dominant and is projected to generate cost savings.

Protocol for a modelling study to assess the clinical and cost-effectiveness of indefinite anticoagulant therapy for first unprovoked venous thromboembolism

INTRODUCTION

Deciding whether to stop or extend anticoagulant therapy indefinitely after completing at least 3 months of initial treatment for a first unprovoked venous thromboembolism (VTE) remains a challenge for clinicians, patients and policy makers. Guidelines suggest an indefinite duration of anticoagulant therapy in these patients, yet its benefits, harms and costs have not been formally assessed. The aim of this proposed modelling study is to assess the differences in clinical benefits, harms and costs of stopping versus continuing anticoagulant therapy indefinitely for a first unprovoked VTE.

METHODS AND ANALYSIS

We will develop a probabilistic Markov model, adopting a 1-month cycle length and a lifetime horizon, to estimate life-years, quality-adjusted life-years, costs and the incremental cost-effectiveness ratios for a simulated population of patients with a first unprovoked VTE who will receive indefinite duration of anticoagulant therapy versus a population who will not receive extended treatment after completing 3 months of initial anticoagulant therapy. The economic evaluation will adopt a third-party payer perspective relating to a Canadian publicly funded healthcare system. Estimates for the probability of relevant clinical events will be informed by systematic reviews and meta-analyses, while costs and utility values will be obtained from published Canadian sources. Stratified analyses based on sex, age and site of initial VTE will also be performed to identify subgroups of patients with a first unprovoked VTE in whom continuing anticoagulant therapy indefinitely might prove to be clinically beneficial and cost-effective over stopping treatment. We will also conduct sensitivity and scenario analyses to assess robustness of study findings to changes in individual or groups of key parameters.

ETHICS AND DISSEMINATION

Ethical approval is not applicable for this study. The results will be disseminated through presentations at relevant conferences and in a manuscript that will be submitted to a peer-reviewed journal.

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.

Left Atrial Appendage Occlusion Versus Oral Anticoagulation in Atrial Fibrillation : A Decision Analysis

BACKGROUND

Left atrial appendage occlusion (LAAO) is a potential alternative to oral anticoagulants in selected patients with atrial fibrillation (AF). Compared with anticoagulants, LAAO decreases major bleeding risk, but there is uncertainty regarding the risk for ischemic stroke compared with anticoagulation.

OBJECTIVE

To determine the optimal strategy for stroke prevention conditional on a patient's individual risks for ischemic stroke and bleeding.

DESIGN

Decision analysis with a Markov model.

DATA SOURCES

Evidence from the published literature informed model inputs.

TARGET POPULATION

Women and men with nonvalvular AF and without prior stroke.

TIME HORIZON

Lifetime.

PERSPECTIVE

Clinical.

INTERVENTION

LAAO versus warfarin or direct oral anticoagulants (DOACs).

OUTCOME MEASURES

The primary end point was clinical benefit measured in quality-adjusted life-years.

RESULTS OF BASE-CASE ANALYSIS

The baseline risks for stroke and bleeding determined whether LAAO was preferred over anticoagulants in patients with AF. The combined risks favored LAAO for higher bleeding risk, but that benefit became less certain at higher stroke risks. For example, at a HAS-BLED score of 5, LAAO was favored in more than 80% of model simulations for CHA₂DS₂-VASc scores between 2 and 5. The probability of LAAO benefit in QALYs (>80%) at lower bleeding risks (HAS-BLED score of 0 to 1) was limited to patients with lower stroke risks (CHA₂DS₂-VASc score of 2). Because DOACs carry lower bleeding risks than warfarin, the net benefit of LAAO is less certain than that of DOACs.

RESULTS OF SENSITIVITY ANALYSIS

Results were consistent using the ORBIT bleeding score instead of the HAS-BLED score, as well as alternative sources for LAAO clinical effectiveness data.

LIMITATION

Clinical effectiveness data were drawn primarily from studies on the Watchman device.

CONCLUSION

Although LAAO could be an alternative to anticoagulants for stroke prevention in patients with AF and high bleeding risk, the overall benefit from LAAO depends on the combination of stroke and bleeding risks in individual patients. These results suggest the need for a sufficiently low stroke risk for LAAO to be beneficial. The authors believe that these results could improve shared decision making when selecting patients for LAAO.

PRIMARY FUNDING SOURCE

None.

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.

Investigation into the Cost-Effectiveness of Extended Posttraumatic Thromboprophylaxis

BACKGROUND

Severely injured patients are at particularly high risk for venous thromboembolism (VTE). Although thromboprophylaxis (PPX) is employed during the inpatient period, patients may continue to be at high risk after discharge. Comparative evidence from surgical subspecialities (eg oncology) reveals benefits of postdischarge (ie extended) PPX. We hypothesized that an extended, postinjury oral thromboprophylaxis regimen would be cost-effective.

STUDY DESIGN

A cost-utility model compared no PPX with a 30-day course of apixaban, dabigatran, enoxaparin, fondaparinux, or rivaroxaban in trauma patients. Immediate events including deep venous thrombosis, pulmonary embolus, or bleeding within 30 days of injury were modeled in a decision tree with patients entering a Markov process to account for sequelae of VTE, including postthrombotic syndrome and chronic thromboembolic pulmonary hypertension. Effectiveness was measured in quality-adjusted life years. One-way and probabilistic sensitivity analyses were performed to identify conditions under which the preferred PPX strategy changed.

RESULTS

Rivaroxaban was the dominant strategy (ie less costly and more effective) compared with no PPX or alternative regimens, delivering 30.21 quality-adjusted life years for $404,546.38. One-way sensitivity analyses demonstrated robust preference for rivaroxaban. When examining only patients with moderate-high or high VTE Risk Assessment Profile scores, rivaroxaban remained the preferred strategy. Probabilistic sensitivity analysis demonstrated a preference for rivaroxaban in 100% of cases at a standard willingness-to-pay threshold of $100,000/quality-adjusted life year.

CONCLUSIONS

A 30-day course of rivaroxaban is a cost-effective extended thromboprophylaxis strategy in trauma patients in this theoretical study. Prospective studies of postdischarge thromboprophylaxis to prevent postinjury VTE are warranted.

Mobile Cardiac Outpatient Telemetry Patch vs Implantable Loop Recorder in Cryptogenic Stroke Patients in the US - Cost-Minimization Model

Purpose

The aim of this study was to compare costs and outcomes of mobile cardiac outpatient telemetry (MCOT) patch followed by implantable loop recorder (ILR) compared to ILR alone in cryptogenic stroke patients from the US health-care payors’ perspective.

Patients and Methods

A quantitative decision tree cost-minimization simulation model was developed. Eligible patients were 18 years of age or older and were diagnosed with having a cryptogenic stroke, without previously documented atrial fibrillation (AF). All patients were assigned first to one then to the alternative monitoring strategies. Following AF detection, patients were initiated on oral anticoagulants (OAC). The model assessed direct costs for one year attributed to MCOT patch followed by ILR or ILR alone using a monitoring duration of 30 days post-cryptogenic stroke.

Results

In the base case modeling, the MCOT patch arm detected 4.6 more patients with AFs compared to the ILR alone arm in a cohort of 1000 patients (209 vs 45 patients with detected AFs, respectively). Using MCOT patch followed by ILR in half of the patients initially undiagnosed with AF leads to significant cost savings of US$4,083,214 compared to ILR alone in a cohort of 1000 patients. Cost per patient with detected AF was significantly lower in the MCOT patch arm $29,598 vs $228,507 in the ILR only arm.

Conclusion

An initial strategy of 30-day electrocardiogram (ECG) monitoring with MCOT patch in diagnosis of AF in cryptogenic stroke patients realizes significant cost-savings compared to proceeding directly to ILR only. Almost 8 times lower costs were achieved with improved detection rates and reduction of secondary stroke risk due to new anticoagulant use in subjects with MCOT patch detected AF. These results strengthen emerging recommendations for prolonged ECG monitoring in secondary stroke prevention.

Patient-specific and healthcare real-world costs of atrial fibrillation in individuals treated with direct oral anticoagulant agents or warfarin

Background

Anticoagulant therapies are used to prevent atrial fibrillation-related strokes, with warfarin and direct oral anticoagulant (DOAC) the most common. In this study, we incorporate direct health care costs, drug costs, travel costs, and lost working and leisure time costs to estimate the total costs of the two therapies.

Methods

This retrospective study used individual-level patient data from 4000 atrial fibrillation (AF) patients from North Karelia, Finland. Real-world data on healthcare use was obtained from the regional patient information system and data on reimbursed travel costs from the database of the Social Insurance Institution of Finland. The costs of the therapies were estimated between June 2017 and May 2018. Using a Geographical Information System (GIS), we estimated travel time and costs for each journey related to anticoagulant therapies. We ultimately applied therapy and travel costs to a cost model to reflect real-world expenditures.

Results

The costs of anticoagulant therapies were calculated from the standpoint of patient and the healthcare service when considering all costs from AF-related healthcare visits, including major complications arising from atrial fibrillation. On average, the annual cost per patient for healthcare in the form of public expenditure was higher when using DOAC therapy than warfarin therapy (average cost = € 927 vs. € 805). Additionally, the average annual cost for patients was also higher with DOAC therapy (average cost = € 406.5 vs. € 296.7). In warfarin therapy, patients had considerable more travel and time costs due the different implementation practices of therapies.

Conclusion

The results indicated that DOAC therapy had higher costs over warfarin from the perspectives of the patient and healthcare service in the study area on average. Currently, the cost of the DOAC drug is the largest determinator of total therapy costs from both perspectives. Despite slightly higher costs, the patients on DOAC therapy experienced less AF-related complications during the study period.

A Meal Replacement Program for the Treatment of Obesity: A Cost-Effectiveness Analysis from the Swiss Payer's Perspective

BACKGROUND

Obesity is a disease associated with high direct medical costs and high indirect costs resulting from productivity loss. The high prevalence of obesity generates the need for payers to identify cost-effective weight loss approaches. Among various weight management techniques, the OPTI (Optifast®) program is a clinically recognised total meal replacement diet that can lead to significant weight loss and reduction in complications. This study's objective is to assess OPTI program's cost-effectiveness in Switzerland in comparison to "no intervention" and pharmacotherapy.

METHODS

An event-driven decision-analytic model was used to estimate the payer's cost savings through the reimbursement of OPTI program over a 1-year period as well as a lifetime in Switzerland. The analysis was performed on a broad population of people with obesity with a body mass index (BMI) higher than 30 kg/m2 following the OPTI program vs two comparators (liraglutide and "no intervention"). The model incorporated a higher risk of complications due to an increased BMI and their related healthcare costs. Data sources included published literature, clinical trials, official Swiss price/tariff lists and national population statistics. The primary perspective was that of a Swiss payer. Scenario analyses - for example, for patients with existing complications (such as myocardial infarction, stroke, type 2 diabetes mellitus) or severe obesity - were conducted to test the robustness of the results.

RESULTS

The OPTI program results in cost savings of CHF 20,886 (€ 18,724) and CHF 15,382 (€ 13,790) per person compared with "no intervention" and liraglutide 3 mg, respectively. In addition, OPTI program led to 1.133 and 0.734 quality-adjusted life years (QALYs) gained respectively against its comparators. Scenario analyses showed similar outcomes with cost savings and QALYs gained.

CONCLUSION

OPTI program is a dominant strategy compared to "no intervention" and liraglutide 3 mg as it leads to both cost savings and QALY gain. Therefore, reimbursing the OPTI program for patients with obesity would be cost-effective for Swiss payers.

Adverse event rates associated with oral anticoagulant treatment early versus later after hospital discharge in older adults: a retrospective population-based cohort study

BACKGROUND

Oral anticoagulants are commonly used high-risk medications, but little is known about their safety in transition from hospital to home. Our objective was to measure the rates of hemorrhage and thromboembolic events among older adults receiving oral anticoagulant treatment early after hospital discharge compared to later.

METHODS

We conducted a retrospective population-based cohort study among Ontario residents aged 66 years or more who started, continued or resumed oral anticoagulant therapy at hospital discharge between September 2010 and March 2015. We calculated the rates of hemorrhage and thromboembolic events requiring hospital admission or an emergency department visit over a 1-year follow-up period, stratified by the first 30 days after discharge and the remainder of the year. We used multivariable regression models, adjusting for covariates, to estimate the effect of sex, prevalent versus incident use, and switching anticoagulants on events.

RESULTS

A total of 123 139 patients (68 408 women [55.6%]; mean age 78.2 yr) were included. About one-quarter (32 563 [26.4%]) had a Charlson Comorbidity Index score of 2 or higher. The rates of hemorrhage and thromboembolic events per 100 person-years were highest during the first 30 days after hospital discharge (25.8, 95% CI 24.8-26.8 and 19.3, 95% CI 18.4-20.2, respectively), falling to 15.7 (95% CI 15.3-16.1) and 6.9 (95% CI 6.6-7.1), respectively, during the subsequent 11 months. Multivariable analysis showed that patients whose anticoagulant was switched in hospital and men had more hemorrhages and thromboembolic events in follow-up.

INTERPRETATION

The first few weeks following hospital discharge represent a very high-risk period for adverse events related to oral anticoagulant treatment among older adults. The results support an intervention trial addressing anticoagulation management in the early postdischarge period.

Oral Anticoagulant Adequacy in Non-Valvular Atrial Fibrillation in Primary Care: A Cross-Sectional Study Using Real-World Data (Fantas-TIC Study)

Background: Oral anticoagulants (OAs) are the treatment to prevent stroke in atrial fibrillation (AF). Anticoagulant treatment choice in non-valvular atrial fibrillation (NVAF) must be individualized, taking current guidelines into account. Adequacy of anticoagulant therapy under the current criteria for NVAF in real-world primary care is presented. Methods: Cross-sectional study, with real-world data from patients treated in primary care (PC). Data were obtained from the System for the Improvement of Research in Primary Care (SIDIAP) database, covering 60,978 NVAF-anticoagulated patients from 287 PC centers in 2018. Results: In total, 41,430 (68%) were treated with vitamin K antagonists (VKAs) and 19,548 (32%) NVAF with direct-acting oral anticoagulants (DOACs). Inadequate prescription was estimated to be 36.0% and 67.6%, respectively. Most DOAC inadequacy (77.3%) was due to it being prescribed as a first-line anticoagulant when there was no history of thromboembolic events or intracranial hemorrhage (ICH). A total of 22.1% had missing estimated glomerular filtration rate (eGFR) values. Common causes of inadequate VKA prescription were poor control of time in therapeutic range (TTR) (98.8%) and ICH (2.2%). Conclusions: Poor adequacy to current criteria was observed, being inadequacy higher in DOACs than in VKAs. TTR and GFR should be routinely calculated in electronic health records (EHR) to facilitate decision-making and patient safety.

Major bleed costs of atrial fibrillation patients treated with factor Xa inhibitor anticoagulants

OBJECTIVE

To examine the healthcare economic burden of atrial fibrillation (AF) patients treated with factor Xa inhibitor (FXaI) anticoagulants who were hospitalized in the US with a major bleed (MB).

METHODS

Adult AF patients treated with FXaIs and hospitalized with an MB were selected from MarketScan databases (1 January 2015-30 April 2018). Patients were grouped into cohorts based on type of MB: intracranial hemorrhage (ICH), gastrointestinal (GI), other types of MB. Healthcare costs in 2019 USD were evaluated for index hospitalizations and during a variable follow-up period in unadjusted and adjusted analyses.

RESULTS

Of the overall AF patient population treated with FXaIs and hospitalized with an MB (n = 7,577), 9.9% had ICH (mean age: 77.9 years; 58% male), 55.9% had GI (mean age: 76.8 years; 52% male), and 34.2% had other types of MB (mean age: 74.4 years; 61% male). Mean index hospitalization costs for ICH, GI, and other type of MB were $54,163, $26,901, and $36,645, respectively; from adjusted analyses, patients with ICH vs. GI spent 1.6 more days in the hospital; mean cost was $15,630 higher. Patients with other types of MB vs. GI spent 0.6 more days in the hospital; mean cost was $5,859 higher. Index hospitalization cost in addition to total all-cause healthcare costs incurred in the follow-up period were $34,522 higher per ICH patient and $11,584 higher per other type of MB patient vs. a GI MB patient.

LIMITATIONS

Since this study was a retrospective observational study using a claims database analysis, a causal relationship between treatment with FXaIs and MB events cannot be established.

CONCLUSIONS

Although all of the evaluated MB types were associated with high hospitalization costs, ICH was associated with the most substantial short- and long-term healthcare economic burden.

Updating the Cost Effectiveness of Oral Anticoagulants for Patients with Atrial Fibrillation Based on Varying Stroke and Bleed Risk Profiles

BACKGROUND

Previous investigations into the cost effectiveness of direct oral anticoagulants only considered individual stroke risk but not bleed risk even though bleeding is an important and potentially fatal side effect for anticoagulated patients.

OBJECTIVE

This study aimed to evaluate the cost effectiveness of dabigatran, rivaroxaban, apixaban, and edoxaban vs warfarin in patients with atrial fibrillation with varying stroke/bleed risk profiles over a lifetime horizon.

METHODS

A Markov micro-simulation was adapted to examine the lifetime costs and quality-adjusted survival of five anticoagulants from a US private payer's perspective. The study hypothetical cohort consisted of 10,000 patients with atrial fibrillation with age, CHA₂DS₂-VASc, and HAS-BLED scores similar to a commercially insured patient with atrial fibrillation cohort. Model input parameters including the efficacy and safety of each strategy, utilities, and cost were estimated from public sources, published literature, and analysis conducted in the IBM MarketScan database. Lifetime cost, quality-adjusted life-years, and incremental cost-effectiveness ratios were assessed for each treatment strategy. Subgroup analyses stratified by age, stroke risk score alone, bleed risk score alone and both were performed. Uncertainty was assessed by a deterministic sensitivity analysis and a probabilistic sensitivity analysis.

RESULTS

The base-case analysis suggested dabigatran was the optimal treatment with an incremental cost-effectiveness ratio of $35,055 per quality-adjusted life-year relative to warfarin. Subgroup analyses stratified by age, stroke risk score, and bleed risk score alone were largely consistent with the base-case analysis. Subgroup analyses stratified by both stroke and bleed risk score showed edoxaban was the preferred treatment in patients with a low stroke and a low or medium bleed risk, and patients with a high stroke and low bleed risk. Apixaban was the preferred treatment in patients with a medium stroke and high bleed risk. Results of the deterministic sensitivity analysis indicate the model results were most sensitive to the drug cost and hazard ratio for stroke and bleeding event. Results of the probability sensitivity analysis showed dabigatran is cost effective vs. other treatments in 32.8% and 42.4% of iterations at a willingness to pay of $50,000/quality-adjusted life-year and a willingness to pay of $100,000/quality-adjusted life year, respectively.

CONCLUSIONS

From a US private payer's perspective, dabigatran appears cost effective compared with other anticoagulants. This study indicated risk stratification especially considering both stroke and bleed risk simultaneously is important not only in clinical practice but also in health technology assessment exercises among patients with atrial fibrillation.

Evaluation of a Pediatric Enoxaparin Dosing Protocol and the Impact on Clinical Outcomes

OBJECTIVES

Enoxaparin has been studied for prophylaxis and treatment of thromboembolism in the pediatric population. Dose-finding studies have suggested higher mean maintenance dose requirements in younger children; however, the current recommended dosing schema endorsed by the American College of Chest Physicians remains conservative, likely secondary to limited data on the safety and efficacy of escalated starting doses. Primary objectives of this study included the identification of patient characteristics and risk factors with associations to anti-factor Xa (anti-Xa) values. The secondary objective was to determine an association between the initial anti-Xa value and thrombus resolution. Safety outcomes related to bleeding were also assessed.

METHODS

This retrospective cohort study reviewed records of all pediatric patients ≤18 years of age who were initiated on therapeutic subcutaneous enoxaparin between October 1, 2008, and October 1, 2018, at Children's Hospitals and Clinics of Minnesota for an indication of incident thrombus (N = 283).

RESULTS

Successful resolution of thrombus was directly associated with attaining a therapeutic anti-Xa concentration upon first laboratory evaluation. Other characteristics with associations to initial anti-Xa values included age, body mass index, and certain diagnoses. The rate of composite bleeding was consistent across concentrations of anti-Xa (p = 0.4944).

CONCLUSIONS

Despite adherence to protocol, the current enoxaparin dosing nomogram is only successful at achieving a therapeutic anti-Xa concentration (0.5-1.0 unit/mL) 55.8% of the time. A more aggressive enoxaparin dosing nomogram is warranted, as delaying time to therapeutic anti-Xa values impacts clinical outcomes, specifically thrombus resolution. Further investigation into characteristics with association to anti-Xa concentrations is needed.

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.

Predictors of oral anticoagulant-associated adverse events in seniors transitioning from hospital to home: a retrospective cohort study protocol

INTRODUCTION

Oral anticoagulants (OACs) are widely prescribed in older adults. High OAC-related adverse event rates in the early period following hospital discharge argue for an analysis to identify predictors. Our objective is to identify and validate clinical and continuity of care variables among seniors discharged from hospital on an OAC, which are independently associated with OAC-related adverse events within 30 days.

METHODS AND ANALYSIS

We propose a population-based retrospective cohort study of all adults aged 66 years or older who were discharged from hospital on an OAC from September 2010 to March 2015 in Ontario, Canada. The primary outcome is a composite of the first hospitalisation or emergency department visit for a haemorrhage or thromboembolic event or mortality within 30 days of hospital discharge. A Cox proportional hazards model will be used to determine the association between the composite outcome and a set of prespecified covariates. A split sample method will be adopted to validate the variables associated with OAC-related adverse events.

ETHICS AND DISSEMINATION

The use of data in this project was authorised under section 45 of Ontario's Personal Health Information Protection Act, which does not require review by a research ethics board. Results will be disseminated via peer-reviewed publications and presentations at conferences and will determine intervention targets to improve OAC management in upcoming randomised trials.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Identifier: NCT02777047; Pre-results.

Patient satisfaction after conversion from warfarin to direct oral anticoagulants for patients on extended duration of anticoagulation for venous thromboembolism - The SWAN Study

Background

Warfarin is an anticoagulant medication proven effective in the initial treatment and secondary prevention of venous thromboembolism. Anti-Xa direct oral anticoagulants are alternatives to warfarin; however there is limited data assessing satisfaction after switching from warfarin to an anti-Xa direct oral anticoagulant in patients for treatment of venous thromboembolism.

Objectives

To assess medication satisfaction in patients requiring anticoagulation for venous thromboembolism after conversion from warfarin to an anti-Xa direct oral anticoagulant.

Methods

A retrospective cohort study with prospective assessment of satisfaction and review of adverse events following anti-Xa direct oral anticoagulant replacement of warfarin for treatment of venous thromboembolism. Out of 165 patients who had switched from warfarin to rivaroxaban or apixaban from an outpatient haematology practice, 126 patients consented for a survey of patient’s relative satisfaction of anti-Xa direct oral anticoagulant therapy compared with previous warfarin therapy using the Anti-Clot Burden and Benefits Treatment Scale and SWAN Score.

Results

The mean Anti-Clot Burden and Benefits and SWAN Score was 93% (56/60) and 83% (24.8/30) respectively reflecting high satisfaction with anti-Xa direct oral anticoagulants. 120 patients stated preference for anti-Xa direct oral anticoagulants over warfarin. Leading perceptions driving this was the reduction in frequency of medical contact and fewer bleeding side effects. Thirteen patients (10.3%) experienced an adverse event after the anti-Xa direct oral anticoagulant switch (majority were non-major bleeding) but most remained on anti-Xa direct oral anticoagulant treatment after management options were implemented with continued high satisfaction scores.

Conclusions

Patient satisfaction with anti-Xa direct oral anticoagulant therapy for the treatment and prevention of venous thromboembolism after switching from warfarin in routine clinical practice appeared high. Improved patient convenience including reduced frequency of medical contact and fewer unpredictable side effects were perceived as significant advantages of anti-Xa direct oral anticoagulants compared to warfarin.

A comparison between warfarin and apixaban: A patient's perspective

BACKGROUND

Novel oral anticoagulants (NOACs) were developed as alternatives to warfarin. However, the patients' preference regarding warfarin or the NOACs has not been established. Quality-of-life (QOL) surveys are a well-established method for determining the patients' preference for a treatment route.

AIMS

This study compared the patients' perspectives on treatment with warfarin versus apixaban using the QOL measures.

SETTINGS AND DESIGN

This cross-sectional study was conducted in 2019 for patients treated with either warfarin or apixaban at King Abdulaziz Medical City, Riyadh, Kingdom of Saudi Arabia.

METHODS

We used a series of descriptive statistics to examine the differences in sociodemographic characteristics among patients. A propensity score-matching approach was employed to reduce the effect of confounding variables that often influence treatment selection. Greedy matching approach was used to analyze the QOL.

RESULTS

A total of 388 patients were identified, of which 124 were matched between the two groups (62 patients in each group). Most of the patients were female, married, below the sufficiency level, educated, and nonsmokers. The patients using warfarin had a significantly better health state (M = 69.64, standard deviation [SD] = 16.52) than those using apixaban (M = 66.33, SD = 23.17), P = 0.011.

CONCLUSIONS

Future studies should explore why patients using apixaban showed lower QOL scores and improve health-care providers' awareness of these issues.

Thirty-Year Risk of Cardiovascular Disease Events in Adolescents with Severe Obesity

OBJECTIVE

Quantifying risk for cardiovascular disease (CVD) events among adolescents is difficult owing to the long latent period between risk factor development and disease outcomes. This study examined the 30-year CVD event risk among adolescents with severe obesity treated with and without metabolic and bariatric surgery (MBS), compared with youths with moderate obesity, overweight, or normal weight.

METHODS

Cross-sectional and longitudinal comparisons of five frequency-matched (age and diabetes status) groups were performed: normal weight (n = 247), overweight (n = 54), obesity (n = 131), severe obesity without MBS (n = 302), and severe obesity undergoing MBS (n = 215). A 30-year CVD event score developed by the Framingham Heart Study was the primary outcome. Data are mean (SD) with differences between time points for MBS examined using linear mixed models.

RESULTS

Preoperatively, the likelihood of CVD events was higher among adolescents undergoing MBS (7.9% [6.7%]) compared with adolescents with severe obesity not referred for MBS (5.5% [4.0%]), obesity (3.9% [3.0%]), overweight (3.1% [2.4%]), and normal weight (1.8% [0.8%]; all P < 0.001). At 1 year after MBS, event risk was significantly reduced (7.9% [6.7%] to 4.0% [3.4%], P < 0.0001) and was sustained for up to 5 years after MBS (P < 0.0001, all years vs. baseline).

CONCLUSIONS

Adolescents with severe obesity are at elevated risk for future CVD events. Following MBS, the predicted risk of CVD events was substantially and sustainably reduced.

New oral anti-coagulants versus vitamin K antagonists in high thromboembolic risk patients

Background

Oral anticoagulant therapy (VKA) is nowadays the mainstay of treatment in primary and secondary stroke prevention in patients with atrial fibrillation. Given the limited risk-benefit ratio of vitamin K antagonists, pharmacological research has been directed towards the development of products that could overcome these limits, new oral anticoagulants were recently introduced: dabigatran, rivaroxaban, apixaban, and edoxaban.

Aim

Scope of the present study was to examine patterns of use, effectiveness, safety and mean annual cost per patient of anticoagulant treatment for non-valvular AF in real clinical practice.

Methods

A retrospective observational cohort study, by using administrative databases (drugs, hospitalizations, clinical visits, lab tests, population registry), was conducted in the Local Health Unit (LHU) of Treviso, Italy, from January 1, 2012 to December 31, 2016.

Results

5597 subjects were selected, 2171 of which satisfied all inclusion criteria. In particular 1355 patients were treated with VKA, 577 patients were treated with NOAC, and 239 patients were treated initially with VKA and subsequently switched to NOAC (switch group). NOAC treatment showed to be superior to VKA and this superiority was statistically significant on both end-points: patients in the NOAC group reported less cardiovascular events (9,9%) and less bleeding episodes (5,5%) versus VKA patients (14,6% and 11,4%; p<,0001 and p = 0,0049, respectively).

The mean cost per patient per year was respectively € 1323,9 for patients treated with NOAC versus € 1003,3 for patients treated with VKA. Cost difference appears to be largely driven by drug cost (€ 767,9 for NOAC versus € 17,7 for VKA patients) and by specialist visits and laboratory tests (€ 318,4 for NOAC versus € 733,4 for VKA patients).

Conclusion

In this retrospective real-world study treatment with NOAC showed to be associated with significant reductions of CV events and bleeding events compared to VKA use, albeit at a higher NHS’ direct cost per patient/year, mainly due to higher drug therapy cost.

A Canadian cost-effectiveness analysis of SAPIEN 3 transcatheter aortic valve implantation compared with surgery, in intermediate and high-risk severe aortic stenosis patients

Background and objectives: The treatment of severe aortic stenosis requires replacement of the defective native valve. Traditionally, this has been done via surgery, but in the last 10 years, transcatheter techniques have emerged. Transcatheter aortic valve implantation (TAVI) is a less invasive option compared to surgical aortic valve replacement (SAVR), and this study evaluates the cost-effectiveness of TAVI versus SAVR in intermediate and high surgical risk patients in Canada. Methods: A Markov model was used to project the costs and quality-adjusted life years (QALYs) gained for TAVI using the SAPIEN 3 valve and SAVR over a 15-year time horizon. The PARTNER I and II studies were used to populate the model in terms of survival, clinical event rates and quality of life over time. The costs of TAVI with SAPIEN 3 and SAVR as well as the costs associated with events included in the model were derived from Canadian administrative and literature data. Costs were expressed in 2018 Canadian dollars and all future costs and QALYs were discounted at a rate of 1.5% annually. Probabilistic and one-way sensitivity analyses were conducted. Results: The incremental cost-effectiveness ratios of TAVI using the SAPIEN 3 valve compared to surgery were $28,154 per QALY gained in intermediate risk patients and $17,237 per QALY gained in high-risk patients. The results of the probabilistic analyses indicated that at willingness-to-pay threshold of $50,000 per QALY gained, the probability of TAVI to be cost-effective was greater than 0.9 in both intermediate-risk and high-risk patients. Sensitivity analyses showed the results were most sensitive to the time horizon used. Conclusion: TAVI using the SAPIEN 3 valve is highly likely to be cost-effective in Canadian patients with severe aortic stenosis who are at intermediate and high surgical risk.

The Guideline-Policy Gap in Direct-Acting Oral Anticoagulants Usage in Atrial Fibrillation: Evidence, Practice, and Public Policy Considerations

Atrial fibrillation has a high disease burden-both in prevalence and associated consequences. Despite anticoagulation being an effective treatment in atrial fibrillation, stroke prevention is slow to reflect evidence-based practice. Real-world data reveal a substantial portion of patients who would benefit from anticoagulation, yet do not receive it adequately or at all. A large part of this suboptimal treatment is due to the underutilization of direct oral anticoagulants (DOACs). In response to abundant evidence published over a short timeframe, international guidelines have adopted DOAC usage ahead of policy and fund holders. This paper reviews the evidence and values that influence published guidelines, patient-physician decision making, and policy framework on DOAC usage. An important factor is the access gap between patients who qualify for DOAC according to evidence-based guidelines and the subset of this cohort who are eligible for DOAC based on government funded policy. We analyse the Canadian health system in detail-including drug approval and funding process. Health care systems in other countries are explored, with emphasis on similar universal health care systems that may help overcome barriers common to Canada. We will discuss strategies to: (1) improve awareness of the risk and preventability of stroke; (2) enable physicians to provide evidence-based DOAC usage; (3) empower patients to improve adherence and persistence; (4) collect real-life data that encourages patient self-monitoring, physician outcomes auditing, and building evidence that is useful for policy makers; and (5) use postmarketing data in negotiating shared risk management between pharmaceuticals and government to improve access to DOACs.

Pharmacist prescribing and care improves cardiovascular risk, but is it cost-effective? A cost-effectiveness analysis of the RxEACH study

Background

The R_xEACH randomized trial demonstrated that community pharmacist prescribing and care reduced the risk for cardiovascular (CV) events by 21% compared to usual care.

Objective

To evaluate the economic impact of pharmacist prescribing and care for CV risk reduction in a Canadian setting.

Methods

A Markov cost-effectiveness model was developed to extrapolate potential differences in long-term CV outcomes, using different risk assessment equations. The mean change in CV risk for the 2 groups of R_xEACH was extrapolated over 30 years, with costs and health outcomes discounted at 1.5% per year. The model incorporated health outcomes, costs and quality of life to estimate overall cost-effectiveness. It was assumed that the intervention would be 50% effective after 10 years. Individual-level results were scaled up to population level based on published statistics (29.2% of Canadian adults are at high risk for CV events). Costs considered included direct medical costs as well as the costs associated with implementing the pharmacist intervention. Uncertainty was explored via probabilistic sensitivity analysis.

Results

It is estimated that the Canadian health care system would save more than $4.4 billion over 30 years if the pharmacist intervention were delivered to 15% of the eligible population. Pharmacist care would be associated with a gain of 576,689 quality-adjusted life years and avoid more than 8.9 million CV events. The intervention is economically dominant (i.e., it is both more effective and reduces costs when compared to usual care).

Conclusion

Across a range of 1-way and probabilistic sensitivity analyses of key parameters and assumptions, pharmacist prescribing and care are both more effective and cost-saving compared to usual care. Canadians need and deserve such care.

Economic Analysis of Apixaban Therapy for Patients With Atrial Fibrillation From a US Perspective: Results From the ARISTOTLE Randomized Clinical Trial

Importance

The Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial reported that apixaban therapy was superior to warfarin therapy in preventing stroke and all-cause death while causing significantly fewer major bleeds. To establish the value proposition of substituting apixiban therapy for warfarin therapy in patients with atrial fibrillation, we performed a cost-effectiveness analysis using patient-level data from the ARISTOTLE trial.

Objective

To assess the cost and cost-effectiveness of apixaban therapy compared with warfarin therapy in patients with atrial fibrillation from the perspective of the US health care system.

Design, Setting, and Participants

This economic analysis uses patient-level resource use and clinical data collected in the ARISTOTLE trial, a multinational randomized clinical trial that observed 18 201 patients (3417 US patients) for a median of 1.8 years between 2006 and 2011.

Interventions

Apixaban therapy vs warfarin therapy.

Main Outcomes and Measures

Within-trial resource use and cost were compared between treatments, using externally derived US cost weights. Life expectancies for US patients were estimated according to their baseline risk and treatment using time-based and age-based survival models developed using the overall ARISTOTLE population. Quality-of-life adjustment factors were obtained from external sources. Cost-effectiveness (incremental cost per quality-adjusted life-year gained) was evaluated from a US perspective, and extensive sensitivity analyses were performed.

Results

Of the 3417 US patients enrolled in ARISTOTLE, the mean (SD) age was 71 (10) years; 2329 (68.2%) were male and 3264 (95.5%) were white. After 2 years of anticoagulation therapy, health care costs (excluding the study drug) of patients treated with apixaban therapy and warfarin therapy were not statistically different (difference, -$60; 95% CI, -$2728 to $2608). Life expectancy, modeled from ARISTOTLE outcomes, was significantly longer with apixaban therapy vs warfarin therapy (7.94 vs 7.54 quality-adjusted life years). The incremental cost, including cost of anticoagulant and monitoring, of achieving these benefits was within accepted US norms ($53 925 per quality-adjusted life year, with 98% likelihood of meeting a $100 000 willingness-to-pay threshold). Results were generally consistent when model assumptions were varied, with lifetime cost-effectiveness most affected by the price of apixaban and the time horizon.

Conclusions and Relevance

Apixaban therapy for ARISTOTLE-eligible patients with atrial fibrillation provides clinical benefits at an incremental cost that represents reasonable value for money judged using US benchmarks for cost-effectiveness.

Trial Registration

clinicaltrials.gov Identifier: NCT00412984.

Use of dabigatran with antiretrovirals

OBJECTIVES

Theoretical and untested interactions between antiretrovirals and direct-acting oral anticoagulants have limited the use of this new class of anticoagulant in people with HIV infection. This case series, the first of its kind, reports on the successful concurrent use of the direct-acting oral anticoagulant dabigatran and antiretroviral therapy.

METHODS

This series involved 14 patients requiring anticoagulation for management of atrial fibrillation, who were either unable or unwilling to take warfarin, and who were receiving concurrent treatment for HIV infection. Participants were treated with dabigatran with dose monitoring to establish the safety and efficacy of concurrent use with antiretrovirals. All were commenced on 110 mg twice daily, increased to 150 mg twice daily if the trough level was < 69.3 ng/mL.

RESULTS

In the 14 patients treated with dabigatran and antiretrovirals, there were no thromboembolic or bleeding complications. Dabigatran treatment was discontinued in one patient because of undetectable dabigatran levels despite dose escalation. Dabigatran levels fell within the fivefold variance seen in the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) study at a dose of either 110 or 150 mg twice daily.

CONCLUSIONS

This case series represents the largest published population to date successfully receiving antiretroviral and direct-acting oral anticoagulant therapy. Given the significant health care burden faced by people living with HIV, the availability of safe anticoagulant therapy without the requirement for monitoring is an important option in this patient population.

Cost-Effectiveness Analysis of Direct-Acting Oral Anticoagulants for Stroke Prevention in Thai Patients with Non-Valvular Atrial Fibrillation and a High Risk of Bleeding

OBJECTIVE

The objective of this study was to assess the cost effectiveness of direct-acting oral anticoagulants for stroke prevention in Thai patients with non-valvular atrial fibrillation and a HAS-BLED score of 3.

METHODS

Total costs (US$) in 2017 and quality-adjusted life-years were estimated over 20 years using a Markov model. A base-case analysis was conducted under a societal perspective, which included direct healthcare, non-healthcare and indirect costs in Thailand. Clinical events for warfarin and utilities were obtained from Thai patients whenever possible. The efficacy of direct-acting oral anticoagulants was derived from trial-based East Asian subgroups and adjusted for time in the target international normalized ratio range of warfarin.

RESULTS

In the base case, use of apixaban instead of warfarin incurred an additional cost of US$20,763 per quality-adjusted life-year gained. Substituting apixaban with rivaroxaban and rivaroxaban with high-dose edoxaban would incur an additional cost per quality-adjusted life-year by US$507 and US$434, respectively. Compared with warfarin, high-dose edoxaban had the lowest incremental cost-effectiveness ratio of US$9704/quality-adjusted life-year, followed by high-dose dabigatran (incremental cost-effectiveness ratio US$11,155/quality-adjusted life-year). The incremental cost-effectiveness ratios based on a payer perspective were similar. The incremental cost-effectiveness ratio was below Thailand's cost-effectiveness threshold when high-dose dabigatran and edoxaban prices were reduced by 50%. Changes in key parameters had a minimal impact on incremental cost-effectiveness ratios.

CONCLUSIONS

For both societal and payer perspectives, high-dose edoxaban with a price below the country cost-effectiveness threshold should be the first anticoagulant option for Thai patients with non-valvular atrial fibrillation and a high risk of bleeding.

Health Care Costs and Utilization of Dabigatran Compared With Warfarin for Secondary Stroke Prevention in Patients With Nonvalvular Atrial Fibrillation: A Retrospective Population Study

BACKGROUND

It remains unclear whether the use of new oral anticoagulants, compared with warfarin, is economically beneficial in Asian countries.

OBJECTIVE

The objective of this study is to compare the health care costs and utilization between dabigatran and warfarin in a real-world nonvalvular atrial fibrillation (NVAF) population.

RESEARCH DESIGN

Data were obtained from the Taiwan National Health Insurance Database, and patients with an NVAF diagnosis between June 1, 2012, and May 31, 2014, were identified using the International Classification of Diseases, Ninth Revision code of 427.31. The patients in the dabigatran cohort were matched 1:2 to those in the warfarin cohort by sex, age, residential region, and a propensity score that incorporated a major bleeding history, CHADS2 score, and Charlson Comorbidity Index. The all-cause health care utilization and associated costs of the 2 treatment groups were compared at 3 and 12 months.

RESULTS

A total of 1149 patients taking dabigatran were identified and matched with 2298 warfarin users. During the 3-month observation period, the likelihood of having at least 1 hospitalization among dabigatran users was significantly lower than that of warfarin users (odds ratio=0.78; P=0.001). Patients in the dabigatran group incurred lower mean emergency department costs ($2383.1 vs. $3033.6), mean ischemic stroke-related hospitalization costs ($8869.5 vs. $13,990.5), and mean all-cause hospitalization costs ($32,402.2 vs. $50,669.9) at 3 months. However, both the mean and median outpatient costs of warfarin users were consistently lower than those of dabigatran users ($17,161.2 vs. $24,931.4 and $10,509.0 vs. $20,671.5, respectively). Similar trends were observed at 12 months, except that the 2 groups had comparable total health care costs.

CONCLUSIONS

The use of dabigatran is associated with lower emergency department and all-cause hospitalization costs but greater outpatient costs in a real-world, NVAF patient population compared with warfarin.

Anticoagulation Therapy for Atrial Fibrillation in Patients With Alzheimer's Disease

Background and Purpose- Direct oral anticoagulants (DOACs) are safer, at least equally efficacious, and cost-effective compared to warfarin for stroke prevention in atrial fibrillation (AF) but they remain underused, particularly in demented patients. We estimated the cost-effectiveness of DOACs compared with warfarin in patients with AF and Alzheimer's disease (AD). Methods- We constructed a microsimulation model to estimate the lifetime costs, quality-adjusted life-years (QALYs), and cost-effectiveness of anticoagulation therapy (adjusted-dose warfarin and various DOACs) in 70-year-old patients with AF and AD from a US societal perspective. We stratified patient cohorts based on stage of AD and care setting. Model parameters were estimated from secondary sources. Health benefits were measured in the number of acute health events, life-years, and QALYs gained. We classified alternatives as cost-effective using a willingness-to-pay threshold of $100 000 per QALY gained. Results- For patients with AF and AD, compared with warfarin, DOACs increase costs but also increase QALYs by reducing the risk of stroke. For mild-AD patients living in the community, edoxaban increased lifetime costs by $6603 and increased QALYs by 0.076 compared to warfarin, yielding an incremental cost-effectiveness ratio of $86 882/QALY gained. Even though DOACs increased QALYs compared with warfarin for all patient groups (ranging from 0.019 to 0.085 additional QALYs), no DOAC treatment alternative had an incremental cost-effectiveness ratio <$150 000/QALY gained for patients with moderate to severe AD. For patients living in a long-term care facility with mild AD, the DOAC with the lowest incremental cost-effectiveness ratio (rivaroxaban) costs $150 169 per QALY gained; for patients with more severe AD, the incremental cost-effectiveness ratios were higher. Conclusions- For patients with AF and mild AD living in the community, edoxaban is cost-effective compared with warfarin. Even though patients with moderate and severe AD living in the community and patients with any stage of AD living in a long-term care setting may obtain positive clinical benefits from anticoagulation treatment, DOACs are not cost-effective compared with warfarin for these populations. Compared to aspirin, no oral anticoagulation (warfarin or any DOAC) is cost effective in patients with AF and AD.

Healthcare Utilization and Expenditures in Working-Age Adults with Atrial Fibrillation: The Effect of Switching from Warfarin to Non-Vitamin K Oral Anticoagulants

OBJECTIVE

Our objective was to evaluate the association between switching from warfarin to non-vitamin K oral anticoagulants (NOACs) and potential drug-drug interactions (DDIs), healthcare utilization, and expenditures in working-age adults with atrial fibrillation (AF).

METHODS

We conducted a retrospective cohort study using data from 2010 to 2015 for patients who switched from warfarin to NOACs (switchers) and those who continued to receive warfarin (non-switchers). We identified medications known or suspected to have clinically significant interactions with NOACs or warfarin. We used multivariate logistic regression, negative binomial, and generalized linear models to evaluate the influence of switching to NOACs and of potential DDIs on inpatient visits, outpatient visits, number of outpatient visits, and non-drug medical expenditures. Inverse probability of treatment weighting was also applied in analyses.

RESULTS

A total of 4126 patients with AF were included in the study. Switching to NOACs was significantly and negatively related to the number of outpatient, inpatient, and emergency room (ER) visits and non-drug medical expenditures. When potential DDIs were included in the models, switching remained significantly associated only with reduced inpatient and outpatient visits. Notably, having at least one potential DDI was associated with an increased likelihood of ER visits and the number of outpatient visits; it was also significantly and positively associated with non-drug medical expenditures.

CONCLUSIONS

Relative to persistent warfarin use, switching to NOACs was associated with fewer inpatient, ER, and outpatient visits and lower non-drug costs. Potential DDIs were also strongly and positively associated with healthcare utilization and expenditures. Both are critical to consider in the management of AF in working-age adults.

Real-World Comparative Effectiveness, Safety, and Health Care Costs of Oral Anticoagulants in Nonvalvular Atrial Fibrillation Patients in the U.S. Department of Defense Population

BACKGROUND

The ARISTOTLE trial demonstrated that apixaban had significantly lower rates of stroke/systemic embolism (SE) and major bleeding than warfarin; however, no direct clinical trials between apixaban and other direct oral anticoagulants (DOACs) are available. Few real-world studies comparing the effectiveness and safety between DOACs have been conducted.

OBJECTIVE

To compare effectiveness, safety, and health care costs among oral anticoagulants (OACs) for nonvalvular atrial fibrillation (NVAF) patients in the U.S. Department of Defense (DoD) population.

METHODS

Adult NVAF patients initiating warfarin or DOACs (apixaban, rivaroxaban, and dabigatran) were selected from U.S. DoD data from January 1, 2013, to September 30, 2015. The first OAC claim date was designated as the index date. Patients initiating another OAC were matched 1:1 to apixaban patients using propensity score matching to balance demographics and clinical characteristics. Cox proportional hazards models were used to estimate the risk of stroke/SE and major bleeding for each OAC versus apixaban. Generalized linear and two-part models with bootstrapping were used to compare all-cause health care costs and stroke/SE-related and major bleeding-related medical costs.

RESULTS

Of the 41,001 eligible patients, 7,607 warfarin-apixaban, 4,129 dabigatran-apixaban, and 11,284 rivaroxaban-apixaban pairs were matched. Warfarin (HR = 1.84; 95% CI = 1.30-2.59; P < 0.001) and rivar-oxaban (HR = 1.46; 95% CI = 1.08-1.98; P = 0.015) were associated with a significantly higher risk of stroke/SE compared with apixaban. Dabigatran (HR = 1.17; 95% CI = 0.68-2.03; P = 0.573) was associated with a numerically higher risk of stroke/SE compared with apixaban. Warfarin (HR = 1.53; 95% CI = 1.24-1.89; P < 0.001), dabigatran (HR = 1.76; 95% CI = 1.27-2.43; P < 0.001), and rivaroxaban (HR = 1.59; 95% CI = 1.34-1.89; P < 0.001) were associated with higher risks of major bleeding compared with apixaban. Compared with apixaban, patients prescribed warfarin incurred numerically higher all-cause total health care costs per patient per month (PPPM) ($2,498 vs. $2,277; P = 0.148) and significantly higher stroke/SE-related ($118 vs. $46; P = 0.012) and major bleeding-related ($166 vs. $76; P = 0.003) medical costs. Dabigatran patients incurred numerically higher all-cause total health care PPPM costs ($2,372 vs. $2,143; P = 0.150) and stroke/SE-related medical costs ($61 vs. $32; P = 0.240) but significantly higher major bleeding-related costs ($114 vs. $58; P = 0.025). Rivaroxaban patients incurred significantly higher all-cause total health care costs ($2,546 vs. $2,200; P < 0.001) and major bleeding-related medical costs PPPM ($137 vs. $69; P < 0.001) but numerically higher stroke/SE-related medical costs PPPM ($58 vs. $38; P = 0.057).

CONCLUSIONS

Among NVAF patients in the U.S. DoD population, warfarin and rivaroxaban were associated with a significantly higher risk of stroke/SE and major bleeding compared with apixaban. Dabigatran use was associated with a numerically higher risk of stroke/SE and a significantly higher risk of major bleeding compared with apixaban. Warfarin and dabigatran incurred numerically higher all-cause total health care costs compared with apixaban. Rivaroxaban was associated with significantly higher all-cause total health care costs compared with apixaban. DISCLOSURES This study was funded by Bristol-Myers Squibb and Pfizer, which were involved in the study design, as well as in the writing and revision of the manuscript. Keshishian and Zhang are paid employees of STATinMED Research, which was paid by Bristol-Myers Squibb and Pfizer to conduct this study and develop the manuscript. Gupta, Rosenblatt, Hede, and Nadkarni are paid employees of Bristol-Myers Squibb. Trocio, Dina, Mardekian, Liu, and Shank are paid employees of Pfizer.

Annual costs attributed to atrial fibrillation management: cross-sectional study of primary healthcare electronic records

Atrial fibrillation (AF) is the most common chronic arrhythmia, with increasing healthcare and economic burden and a prevalence which increases with progressive ageing. This study aims to describe overall annual costs per patient for management of non-valvular AF in a primary healthcare (PHC) setting and compare these costs between the groups of patients treated with vitamin K antagonists, antiplatelets or non-treated through a population-based study conducted with electronic health records. We analysed annual costs per person of 19,787 patients in 2012; PHC visits, hospital admissions, AF-related events requiring hospital admission, referrals to secondary specialists, sick leave, diagnostic tests and laboratory tests at PHC level, including INR determinations performed in PHC, and drug therapy. Higher costs of AF management were associated with increasing age, male sex, stroke and bleeding risks, comorbidities and occurrence of events associated to AF. The sensitivity analyses conducted showed that PHC visits and hospitalizations represented the most important part of overall costs for all patients.

Prior Authorization and Canadian Public Utilization of Direct-Acting Oral Anticoagulants

Purpose:

Provincial public drug formularies in Canada have different mechanisms for reimbursement of direct-acting oral anticoagulants (DOACs). We investigate how these differences influence DOAC utilization and expenditure across the country.

Methods:

We conducted a population-based, cross-sectional study of all out-patient prescriptions for OACs dispensed to public beneficiaries between January 1, 2010, and June 30, 2015. We calculated quarterly rates of OAC use and expenditures stratified by OAC type and province.

Results:

The greatest increase in quarterly rates of DOAC utilization occurred in provinces with more liberal mechanism of drug coverage: Ontario by 462%, Alberta by 425% and Quebec by 1,924%. This translated to increased expenditure on overall OAC by 270%, 204% and 390%, respectively. In contrast, provinces with more stringent mechanisms had low rates of DOAC utilization and expenditure.

Conclusions:

DOAC utilization and expenditure is considerably different across Canada, associated with provincial difference in reimbursement mechanism.

A case study in distributed team science in research using electronic health records

Introduction

Due to various regulatory barriers, it is increasingly difficult to move pseudonymised routine health data across platforms and among jurisdictions. To tackle this challenge, we summarized five approaches considered to support a scientific research project focused on the risk of the new non-vitamin K Target Specific Oral Anticoagulants (TSOACs) and collaborated between the Farr institute in Wales and Scotland.

Approach

In Wales, routinely collected health records held in the Secure Anonymous Information Linkage (SAIL) Databank were used to identify the study cohort. In Scotland, data was extracted from national dataset resources administered by the eData Research & Innovation Service (eDRIS) and stored in the Scottish National Data Safe Haven. We adopted a federated data and multiple analysts approach, but arranged simultaneous accesses for Welsh and Scottish analysts to generate study cohorts separately by implementing the same algorithm. Our study cohort across two countries was boosted to 6,829 patients towards risk analysis. Source datasets and data types applied to generate cohorts were reviewed and compared by analysts based on both sites to ensure the consistency and harmonised output.

Discussion

This project used a fusion of two approaches among five considered. The approach we adopted is a simple, yet efficient and cost-effective method to ensure consistency in analysis and coherence with multiple governance systems. It has limitations and potentials of extending and scaling. It can also be considered as an initialisation of a developing infrastructure to support a distributed team science approach to research using Electronic Health Records (EHRs) across the UK and more widely.

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.

Approaches to Direct Oral Anticoagulant Selection in Practice

Direct oral anticoagulants (DOACs) carry many advantages over warfarin and are now considered first line or an alternative for mnay thromboembolic disorders. With the emergence of 5 DOAC agents to the market as well as the accumulating evidence gathered from head-to-head comparisons between the agents, we attempt to provide direction for clinicians when selecting the most appropriate DOAC agent. Important aspects such as efficacy, safety, cost effectiveness, approved indications, and other drug-related factors will be addressed to highlight the major similarities and diversities among the DOACs. When considering the safety profile of DOACs, evidence points toward apixaban as the safest followed by dabigatran and then rivaroxaban. On the other hand, dabigatran currently has the only approved antidote, idarucizumab. According to the approved DOAC indications, rivaroxaban may be favorable in European countries given its additional indication for secondary prevention of myocardial infarction. Following rivaroxaban, dabigatran and apixaban have the largest number of approved indications and lastly comes edoxaban and then betrixaban. For patients with renal impairment, betrixaban is the safest option, followed by apixaban and edoxaban, then rivaroxaban and lastly dabigatran. When considering DOAC dosing, rivaroxaban, edoxaban, and betrixaban are mainly dosed once daily compared to dabigatran and apixaban, which are dosed twice daily. However, rivaroxaban and betrixaban must be administered with food, which adds another level of complexity to the DOAC dosing. Lastly, taking into consideration drug interactions, dabigatran, edoxaban, and betrixaban have the least amount of interactions compared to apixaban and rivaroxaban. Each DOAC has its own set of features that makes it better suited than others based on the exact clinical situation. Therefore, no conclusion can be drawn to the most superior DOAC based on the aspects discussed in this review.

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%.

Atrial fibrillation in aging population

With aging, the pathogenesis processes of atrial fibrillation (AF) are heightened. In this article, we review the mechanisms that predispose elderly patients to AF. We also highlight the unique features in diagnosis, stroke prevention, and treatment strategies for the elderly patient with AF.

Real-world comparison of all-cause hospitalizations, hospitalizations due to stroke and major bleeding, and costs for non-valvular atrial fibrillation patients prescribed oral anticoagulants in a US health plan

AIMS

To compare the risk of all-cause hospitalization and hospitalizations due to stroke/systemic embolism (SE) and major bleeding, as well as associated healthcare costs for non-valvular atrial fibrillation (NVAF) patients initiating apixaban, dabigatran, rivaroxaban, or warfarin.

MATERIALS AND METHODS

NVAF patients initiating apixaban, dabigatran, rivaroxaban, or warfarin were selected from the OptumInsight Research Database from January 1, 2013-September 30, 2015. Propensity score matching (PSM) was performed between apixaban and each oral anticoagulant. Cox models were used to estimate the risk of stroke/SE and major bleeding. Generalized linear and 2-part models were used to compare healthcare costs.

RESULTS

Of the 47,634 eligible patients, 8,328 warfarin-apixaban pairs, 3,557 dabigatran-apixaban pairs, and 8,440 rivaroxaban-apixaban pairs were matched. Compared to apixaban, warfarin patients were associated with a significantly higher risk of all-cause (hazard ratio [HR] = 1.30; 95% confidence interval [CI] = 1.21-1.40) as well as stroke/SE-related (HR = 1.60; 95% CI = 1.23-2.07) and major bleeding-related (HR = 1.95; 95% CI = 1.60-2.39) hospitalization; rivaroxaban patients were associated with a higher risk of all-cause (HR = 1.15; 95% CI = 1.07-1.24) and major bleeding-related hospitalization (HR = 1.71; 95% CI = 1.39-2.10); and dabigatran patients were associated with a higher risk of major bleeding hospitalization (HR = 1.46, 95% CI = 1.02-2.10). Warfarin patients had significantly higher major bleeding-related and total all-cause healthcare costs compared to apixaban patients. Rivaroxaban patients had significantly higher major bleeding-related costs compared to apixaban patients. No significant results were found for the remaining comparisons.

LIMITATIONS

No causal relationships can be concluded, and unobserved confounders may exist in this retrospective database analysis.

CONCLUSIONS

This study demonstrated a significantly higher risk of hospitalization (all-cause, stroke/SE, and major bleeding) associated with warfarin, a significantly higher risk of major bleeding hospitalization associated with dabigatran or rivaroxaban, and a significantly higher risk of all-cause hospitalization associated with rivaroxaban compared to apixaban. Lower major bleeding-related costs were observed for apixaban patients compared to warfarin and rivaroxaban patients.

THE GAP BETWEEN ECONOMIC EVALUATIONS AND CLINICAL PRACTICE: A SYSTEMATIC REVIEW OF ECONOMIC EVALUATIONS ON DABIGATRAN FOR ATRIAL FIBRILLATION

OBJECTIVES

As model-based economic evaluations (MBEEs) are widely used to make decisions in the context of policy, it is imperative that they represent clinical practice. Here, we assess the relevance of MBEEs on dabigatran for the prevention of stroke in patients with atrial fibrillation (AF).

METHODS

We performed a systematic review on the basis of a developed questionnaire, tailored to oral anticoagulation in patients with AF. Included studies had a full body text in English, compared dabigatran with a vitamin K antagonist, were not dedicated to one or more subgroup(s), and yielded an incremental cost-effectiveness ratio. The relevance of all MBEEs was assessed on the basis of ten context-independent factors, which encompassed clinical outcomes and treatment duration. The MBEEs performed for the United States were assessed on the basis of seventeen context-dependent factors, which were related to the country's target population and clinical environment.

RESULTS

The search yielded twenty-nine MBEEs, of which six were performed for the United States. On average, 54 percent of the context-independent factors were included per study, and 37 percent of the seventeen context-dependent factors in the U.S.

STUDIES

The share of relevant factors per study did not increase over time.

CONCLUSIONS

MBEEs on dabigatran leave out several relevant factors, limiting their usefulness to decision makers. We strongly urge health economic researchers to improve the relevance of their MBEEs by including context-independent relevance factors, and modeling context-dependent factors befitting the decision context concerned.

Oral anticoagulants for prevention of stroke in atrial fibrillation: systematic review, network meta-analysis, and cost effectiveness analysis

Objective To compare the efficacy, safety, and cost effectiveness of direct acting oral anticoagulants (DOACs) for patients with atrial fibrillation.Design Systematic review, network meta-analysis, and cost effectiveness analysis. Data sources Medline, PreMedline, Embase, and The Cochrane Library.Eligibility criteria for selecting studies Published randomised trials evaluating the use of a DOAC, vitamin K antagonist, or antiplatelet drug for prevention of stroke in patients with atrial fibrillation.Results 23 randomised trials involving 94 656 patients were analysed: 13 compared a DOAC with warfarin dosed to achieve a target INR of 2.0-3.0. Apixaban 5 mg twice daily (odds ratio 0.79, 95% confidence interval 0.66 to 0.94), dabigatran 150 mg twice daily (0.65, 0.52 to 0.81), edoxaban 60 mg once daily (0.86, 0.74 to 1.01), and rivaroxaban 20 mg once daily (0.88, 0.74 to 1.03) reduced the risk of stroke or systemic embolism compared with warfarin. The risk of stroke or systemic embolism was higher with edoxaban 60 mg once daily (1.33, 1.02 to 1.75) and rivaroxaban 20 mg once daily (1.35, 1.03 to 1.78) than with dabigatran 150 mg twice daily. The risk of all-cause mortality was lower with all DOACs than with warfarin. Apixaban 5 mg twice daily (0.71, 0.61 to 0.81), dabigatran 110 mg twice daily (0.80, 0.69 to 0.93), edoxaban 30 mg once daily (0.46, 0.40 to 0.54), and edoxaban 60 mg once daily (0.78, 0.69 to 0.90) reduced the risk of major bleeding compared with warfarin. The risk of major bleeding was higher with dabigatran 150 mg twice daily than apixaban 5 mg twice daily (1.33, 1.09 to 1.62), rivaroxaban 20 mg twice daily than apixaban 5 mg twice daily (1.45, 1.19 to 1.78), and rivaroxaban 20 mg twice daily than edoxaban 60 mg once daily (1.31, 1.07 to 1.59). The risk of intracranial bleeding was substantially lower for most DOACs compared with warfarin, whereas the risk of gastrointestinal bleeding was higher with some DOACs than warfarin. Apixaban 5 mg twice daily was ranked the highest for most outcomes, and was cost effective compared with warfarin.Conclusions The network meta-analysis informs the choice of DOACs for prevention of stroke in patients with atrial fibrillation. Several DOACs are of net benefit compared with warfarin. A trial directly comparing DOACs would overcome the need for indirect comparisons to be made through network meta-analysis.Systematic review registration PROSPERO CRD 42013005324.

Systemic Thrombolysis, Catheter-Directed Thrombolysis, and Anticoagulation for Intermediate-risk Pulmonary Embolism: A Simulation Modeling Analysis

OBJECTIVES

Decision making around the use of thrombolysis for patients with intermediate-risk (submassive) pulmonary embolism (PE) remains challenging. Studies indicate favorable clinical outcomes with systemic thrombolytics (intravenous tissue plasminogen activator [IV tPA]), but the risk of major bleeding and hemorrhagic stroke is a deterrent. Catheter-directed thrombolysis (CDT) may be a preferable strategy, as it has been shown to have a lower risk of bleeding than systemic thrombolysis. However, a three-arm randomized control study comparing IV tPA, CDT, and anticoagulation alone, with long-term follow up, would be costly and is unlikely to be performed. The aim of this study was to use decision modeling to quantitatively estimate the differences between the three strategies.

METHODS

We created an individual-level state-transition model to simulate long-term outcomes of a hypothetical patient cohort treated with IV tPA, CDT, or anticoagulation alone. Our model incorporated clinical randomized controlled trial and longitudinal study data to inform patient characteristics and outcomes specific to each study arm. The base case was a 65-year-old patient. Additionally, we utilized preliminary data published by the Pulmonary Embolism Response Team at the Massachusetts General Hospital. Variance in model inputs was addressed with deterministic and probabilistic sensitivity analyses. Our primary endpoint was quality-adjusted life-years (QALYs). Secondary endpoints included total cost and incremental cost-effectiveness ratios (ICERs).

RESULTS

Catheter-directed thrombolysis (mean, 95% confidence interval [CI] = 7.388 [7.381-7.396] QALYs) resulted in the most long-term utility for eligible patients compared to anticoagulation alone (7.352 [7.345-7.360] QALYs) or IV tPA (7.343 [7.336-7.351] QALYs). Patients receiving CDT had an elevated risk of hemorrhagic stroke in comparison to anticoagulation alone; however, patients treated with anticoagulation alone were more likely to experience recurrent PE associated adverse outcomes. Results were stable with sensitivity analyses varying age and sex. Our probabilistic sensitivity analysis assessing joint variance predicts CDT to be the most effective strategy, when measured by mean QALYs, in 98.4% of runs, while systemic thrombolysis was favored over anticoagulation alone 34.4% of the time. The ICER of CDT compared to anticoagulation was $317,042 per QALY gained.

CONCLUSION

In our model, for those eligible, CDT results in the largest number of QALYs for patients with intermediate-risk PE, although it is relatively expensive and the absolute difference in QALYs between anticoagulation alone and CDT is small. Future studies that provide data on longitudinal quality-of-life outcomes of patients treated for PE and characteristics of CDT would be beneficial to augment model inputs, inform assumptions, and validate results.

Screening for atrial fibrillation in Canadian pharmacies: an economic evaluation

BACKGROUND

Screening for undiagnosed atrial fibrillation may lead to treatment with oral anticoagulation therapy, which can decrease the risk of ischemic stroke. The objective of this study was to conduct an economic evaluation of the Program for the Identification of 'Actionable' Atrial Fibrillation in the Pharmacy Setting (PIAAF-Pharmacy), which screened 1145 participants aged 65 years or more at 30 community pharmacies in Ontario and Alberta between October 2014 and April 2015.

METHODS

We used a 2-part decision model to evaluate the short- and long-term costs and quality-adjusted life-years (QALYs) of a pharmacy screening program for atrial fibrillation compared to no screening. Data from the PIAAF-Pharmacy study were used for the short-term model, and the relevant literature was used to extrapolate the benefits of the PIAAF-Pharmacy study in the long-term model. Costs and QALYs were calculated from a payer perspective over a lifetime horizon and were discounted at 1.5%/year.

RESULTS

Screening for atrial fibrillation in pharmacies was associated with higher costs ($26) and more QALYs (0.0035) compared to no screening, yielding an incremental cost per QALY gained of $7480. Univariate and probabilistic sensitivity analyses confirmed that screening for atrial fibrillation in a pharmacy setting was a cost-effective strategy.

INTERPRETATION

Our results support screening for atrial fibrillation in Canadian pharmacies. Given this finding, efforts should be made by provincial governments and pharmacies to implement such programs in Canada. The addition of atrial fibrillation screening alongside screening and management of other cardiovascular conditions may help to reduce the burden of stroke.

Impact of Spontaneous Extracranial Bleeding Events on Health State Utility in Patients with Atrial Fibrillation: Results from the ENGAGE AF-TIMI 48 Trial

Background

The impact of different types of extracranial bleeding events on health‐related quality of life and health‐state utility among patients with atrial fibrillation is not well understood.

Methods and Results

The ENGAGE AF‐TIMI 48 (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation–Thrombolysis in Myocardial Infarction 48) Trial compared edoxaban with warfarin with respect to the prevention of stroke or systemic embolism in atrial fibrillation. Data from the EuroQol‐5D (EQ‐5D‐3L) questionnaire, prospectively collected at 3‐month intervals for up to 48 months, were used to estimate the impact of different categories of bleeding events on health‐state utility over 12 months following the event. Longitudinal mixed‐effect models revealed that major gastrointestinal bleeds and major nongastrointestinal bleeds were associated with significant immediate decreases in utility scores (−0.029 [−0.044 to −0.014; P<0.001] and −0.029 [−0.046 to −0.012; P=0.001], respectively). These effects decreased in magnitude over time, and were no longer significant for major nongastrointestinal bleeds at 9 months, but remained borderline significant for major gastrointestinal bleeds at 12 months. Clinically relevant nonmajor and minor bleeds were associated with smaller but measurable immediate impacts on utility (−0.010 [−0.016 to −0.005] and −0.016 [−0.024 to −0.008]; P<0.001 for both), which remained relatively constant and statistically significant over the 12 months following the bleeding event.

Conclusions

All categories of bleeding events were associated with negative impacts on health‐state utility in patients with atrial fibrillation. Major bleeds were associated with relatively large immediate decreases in utility scores that gradually diminished over 12 months; clinically relevant nonmajor and minor bleeds were associated with smaller immediate decreases in utility that persisted over 12 months.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT00781391.

Factors influencing warfarin control in Australia and Singapore

INTRODUCTION

Warfarin is widely used for patients with non-valvular atrial fibrillation (NVAF). Variations in warfarin control, as measured by time in therapeutic range (TTR), have been reported across different regions and ethnicities, particularly between Western and Asian countries. However, there is limited data on comparative factors influencing warfarin control in Caucasian and Asian patients. Therefore, the aim of this study was to determine warfarin control and potential factors influencing this in patients with NVAF in Australia and Singapore.

METHODS

Retrospective data was collected for patients receiving warfarin for January to June 2014 in Australia and Singapore. TTR was calculated for individuals with mean patient TTR used for analysis. Possible influential factors on TTR were analysed including age, gender, concurrent co-morbidities, and concurrent medication.

RESULTS

The mean TTR was significantly higher in Australia (82%) than Singapore (58%). At both sites, chronic kidney disease significantly lowered this TTR. Further factors influencing control were anaemia and age<60years in Australia, and vascular disease, CHA₂DS₂-VASc score of 6, and concurrent platelet inhibitor therapy in Singapore.

DISCUSSION

Warfarin control was significantly higher in Australia compared to Singapore, however chronic kidney disease reduced control at both sites. The different levels of control in these two countries, together with patient factors further reducing control may impact on anticoagulant choice in these countries with better outcomes from warfarin in Australia compared to Singapore.