Cost-Effectiveness of Dabigatran for Stroke Prophylaxis in 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.

Safety Issues of Herb-Warfarin Interactions

Warfarin is a popular anticoagulant with high global demand. However, studies have underlined serious safety issues when warfarin is consumed concomitantly with herbs or its formulations. This review aimed to highlight the mechanisms behind herb-warfarin interactions while laying special emphasis on its PKPD interactions and evidence on Herb-Warfarin Interaction (HWI) with regards to three different scenarios, such as when warfarin is consumed with herbs, taken as foods or prescribed as medicine, or when used in special situations. A targeted literature methodology involving different scientific databases was adopted for acquiring information on the subject of HWIs. Results of the present study revealed some of the fatal consequences of HWI, including post-operative bleeding, thrombosis, subarachnoid hemorrhage, and subdural hematomas occurring as a result of interactions between warfarin and herbs or commonly associated food products from Hypericum perforatum, Zingiber officinale, Vaccinium oxycoccos, Citrus paradisi, and Punica granatum. In terms of PK-PD parameters, herbs, such as Coptis chinensis Franch. and Phellodendron amurense Rupr., were found to compete with warfarin for binding with plasma proteins, leading to an increase in free warfarin levels in the bloodstream, resulting in its augmented antithrombic effect. Besides, HWIs were also found to decrease International Normalised Ratio (INR) levels following the consumption of Persea americana or avocado. Therefore, there is an urgent need for an up-to-date interaction database to educate patients and healthcare providers on these interactions, besides promoting the adoption of novel technologies, such as natural language processing, by healthcare professionals to guide them in making informed decisions to avoid HWIs.

Bleeding risk in patients prescribed dual antiplatelet therapy and triple therapy after coronary interventions: the ADAPTT retrospective population-based cohort studies

Background

Bleeding among populations undergoing percutaneous coronary intervention or coronary artery bypass grafting and among conservatively managed patients with acute coronary syndrome exposed to different dual antiplatelet therapy and triple therapy (i.e. dual antiplatelet therapy plus an anticoagulant) has not been previously quantified.

Objectives

The objectives were to estimate hazard ratios for bleeding for different antiplatelet and triple therapy regimens, estimate resources and the associated costs of treating bleeding events, and to extend existing economic models of the cost-effectiveness of dual antiplatelet therapy.

Design

The study was designed as three retrospective population-based cohort studies emulating target randomised controlled trials.

Setting

The study was set in primary and secondary care in England from 2010 to 2017.

Participants

Participants were patients aged ≥ 18 years undergoing coronary artery bypass grafting or emergency percutaneous coronary intervention (for acute coronary syndrome), or conservatively managed patients with acute coronary syndrome.

Data sources

Data were sourced from linked Clinical Practice Research Datalink and Hospital Episode Statistics.

Interventions

Coronary artery bypass grafting and conservatively managed acute coronary syndrome: aspirin (reference) compared with aspirin and clopidogrel. Percutaneous coronary intervention: aspirin and clopidogrel (reference) compared with aspirin and prasugrel (ST elevation myocardial infarction only) or aspirin and ticagrelor.

Main outcome measures

Primary outcome: any bleeding events up to 12 months after the index event. Secondary outcomes: major or minor bleeding, all-cause and cardiovascular mortality, mortality from bleeding, myocardial infarction, stroke, additional coronary intervention and major adverse cardiovascular events.

Results

The incidence of any bleeding was 5% among coronary artery bypass graft patients, 10% among conservatively managed acute coronary syndrome patients and 9% among emergency percutaneous coronary intervention patients, compared with 18% among patients prescribed triple therapy. Among coronary artery bypass grafting and conservatively managed acute coronary syndrome patients, dual antiplatelet therapy, compared with aspirin, increased the hazards of any bleeding (coronary artery bypass grafting: hazard ratio 1.43, 95% confidence interval 1.21 to 1.69; conservatively-managed acute coronary syndrome: hazard ratio 1.72, 95% confidence interval 1.15 to 2.57) and major adverse cardiovascular events (coronary artery bypass grafting: hazard ratio 2.06, 95% confidence interval 1.23 to 3.46; conservatively-managed acute coronary syndrome: hazard ratio 1.57, 95% confidence interval 1.38 to 1.78). Among emergency percutaneous coronary intervention patients, dual antiplatelet therapy with ticagrelor, compared with dual antiplatelet therapy with clopidogrel, increased the hazard of any bleeding (hazard ratio 1.47, 95% confidence interval 1.19 to 1.82), but did not reduce the incidence of major adverse cardiovascular events (hazard ratio 1.06, 95% confidence interval 0.89 to 1.27). Among ST elevation myocardial infarction percutaneous coronary intervention patients, dual antiplatelet therapy with prasugrel, compared with dual antiplatelet therapy with clopidogrel, increased the hazard of any bleeding (hazard ratio 1.48, 95% confidence interval 1.02 to 2.12), but did not reduce the incidence of major adverse cardiovascular events (hazard ratio 1.10, 95% confidence interval 0.80 to 1.51). Health-care costs in the first year did not differ between dual antiplatelet therapy with clopidogrel and aspirin monotherapy among either coronary artery bypass grafting patients (mean difference £94, 95% confidence interval -£155 to £763) or conservatively managed acute coronary syndrome patients (mean difference £610, 95% confidence interval -£626 to £1516), but among emergency percutaneous coronary intervention patients were higher for those receiving dual antiplatelet therapy with ticagrelor than for those receiving dual antiplatelet therapy with clopidogrel, although for only patients on concurrent proton pump inhibitors (mean difference £1145, 95% confidence interval £269 to £2195).

Conclusions

This study suggests that more potent dual antiplatelet therapy may increase the risk of bleeding without reducing the incidence of major adverse cardiovascular events. These results should be carefully considered by clinicians and decision-makers alongside randomised controlled trial evidence when making recommendations about dual antiplatelet therapy.

Limitations

The estimates for bleeding and major adverse cardiovascular events may be biased from unmeasured confounding and the exclusion of an eligible subgroup of patients who could not be assigned an intervention. Because of these limitations, a formal cost-effectiveness analysis could not be conducted.

Future work

Future work should explore the feasibility of using other UK data sets of routinely collected data, less susceptible to bias, to estimate the benefit and harm of antiplatelet interventions.

Trial registration

This trial is registered as ISRCTN76607611.

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 27, No. 8. See the NIHR Journals Library website for further project information.

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.

Quality of anticoagulation with warfarin in rural Chhattisgarh, India

Background & objectives

In most of rural India, warfarin is the only oral anticoagulant available. Among patients taking warfarin, there is a strong association between poor control of the international normalized ratio (INR) and adverse events. This study was aimed to quantify INR control in a secondary healthcare system in rural Chhattisgarh, India.

Methods

The INR data were retrospectively obtained from all patients taking warfarin during 2014-2016 at a secondary healthcare system in rural Chhattisgarh, India. Patients attending the clinic had their INR checked at the hospital laboratory and their warfarin dose adjusted by a physician on the same day. The time in therapeutic range (TTR) was calculated for patients who had at least two INR visits.

Results

The 249 patients had 2839 INR visits. Their median age was 46 yr, and the median body mass index was 17.7 kg/m^[2]. They lived a median distance of 78 km (2-3 h of travel) from the hospital. The median INR was 1.7 for a target INR of 2.0-3.0 (n=221) and 2.1 for a target of 2.5-3.5 (n=28). The median TTR was 13.0 per cent, and INR was subtherapeutic 66.0 per cent of the time. Distance from the hospital was not correlated with TTR.

Interpretation & conclusions

INR values were subtherapeutic two-thirds of the time, and TTR values were poor regardless of distance from the health centre. Future studies should be done to identify interventions to improve INR control.

A cost-effectiveness analysis model of Preventicus atrial fibrillation screening from the point of view of statutory health insurance in Germany

BACKGROUND

With atrial fibrillation (AF) the risk of stroke is 4.2-fold increased to a comparable population without AF. This risk decreases by up to 70% if AF is detected early enough and effective stroke preventive measures are taken as recommended by international guidelines. Long-term studies found large number of subjects with undiagnosed AF. Preventicus Heartbeats" is a hands-on screening tool for use on smartphone to diagnose AF with high sensitivity and specificity. The aim of this study is to research the cost-effectiveness of systematic screening for AF with this smartphone application.

METHOD

Employing a Markov model we analysed the cost-effectiveness of the "Preventicus Heartbeats" screening for Germany, i.e. from the perspective of German statutory sick funds.

RESULTS

For a cohort of 10,000 insured 75-year-old the use of the diagnostic app could avoid 60 strokes in the remaining lifetime thereof 32 strokes in the next four years. Former models have applied similar cohorts. The same cohort showed an increase in quality-adjusted life years (QALY) in the remaining lifetime of 165 QALYs in the scenario with screening versus. without screening and a decrease in discounted lifetime costs (including risk compensation effects) of €129 per participant (€148 for male, €114 for female participants).

CONCLUSIONS

The modelling demonstrates the health benefits and economic effects of an implementation of a systematic screening on AF with "Preventicus Heartbeats", given the perspective of the German payer, the statutory health care system.

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.

Cost-Effectiveness of Rate- and Rhythm-Control Drugs for Treating Atrial Fibrillation in Korea

PURPOSE

Although the economic and mortality burden of atrial fibrillation (AF) is substantial, it remains unclear which treatment strategies for rate and rhythm control are most cost-effective. Consequently, economic factors can play an adjunctive role in guiding treatment selection.

MATERIALS AND METHODS

We built a Markov chain Monte Carlo model using the Korean Health Insurance Review & Assessment Service database. Drugs for rate control and rhythm control in AF were analyzed. Cost-effective therapies were selected using a cost-effectiveness ratio, calculated by net cost and quality-adjusted life years (QALY).

RESULTS

In the National Health Insurance Service data, 268149 patients with prevalent AF (age ≥18 years) were identified between January 1, 2013 and December 31, 2015. Among them, 212459 and 55690 patients were taking drugs for rate and rhythm control, respectively. Atenolol cost $714/QALY. Among the rate-control medications, the cost of propranolol was lowest at $487/QALY, while that of carvedilol was highest at $1363/QALY. Among the rhythm-control medications, the cost of pilsicainide was lowest at $638/QALY, while that of amiodarone was highest at $986/QALY. Flecainide and propafenone cost $834 and $830/QALY, respectively. The cost-effectiveness threshold of all drugs was lower than $30000/QALY. Compared with atenolol, the rate-control drugs propranolol, betaxolol, bevantolol, bisoprolol, diltiazem, and verapamil, as well as the rhythm-control drugs sotalol, pilsicainide, flecainide, propafenone, and dronedarone, showed better incremental cost-effectiveness ratios.

CONCLUSION

Propranolol and pilsicainide appear to be cost-effective in patients with AF in Korea assuming that drug usage or compliance is the same.

Directly Acting Oral Anticoagulants for the Prevention of Stroke in Atrial Fibrillation in England and Wales: Cost-Effectiveness Model and Value of Information Analysis

Objectives. Determine the optimal, licensed, first-line anticoagulant for prevention of ischemic stroke in patients with non-valvular atrial fibrillation (AF) in England and Wales from the UK National Health Service (NHS) perspective and estimate value to decision making of further research. Methods. We developed a cost-effectiveness model to compare warfarin (international normalized ratio target range 2-3) with directly acting (or non-vitamin K antagonist) oral anticoagulants (DOACs) apixaban 5 mg, dabigatran 150 mg, edoxaban 60 mg, and rivaroxaban 20 mg, over 30 years post treatment initiation. In addition to death, the 17-state Markov model included the events stroke, bleed, myocardial infarction, and intracranial hemorrhage. Input parameters were informed by systematic literature reviews and network meta-analysis. Expected value of perfect information (EVPI) and expected value of partial perfect information (EVPPI) were estimated to provide an upper bound on value of further research. Results. At willingness-to-pay threshold £20,000, all DOACs have positive expected incremental net benefit compared to warfarin, suggesting they are likely cost-effective. Apixaban has highest expected incremental net benefit (£7533), followed by dabigatran (£6365), rivaroxaban (£5279), and edoxaban (£5212). There was considerable uncertainty as to the optimal DOAC, with the probability apixaban has highest net benefit only 60%. Total estimated population EVPI was £17.94 million (17.85 million, 18.03 million), with relative effect between apixaban versus dabigatran making the largest contribution with EVPPI of £7.95 million (7.66 million, 8.24 million). Conclusions. At willingness-to-pay threshold £20,000, all DOACs have higher expected net benefit than warfarin but there is considerable uncertainty between the DOACs. Apixaban had the highest expected net benefit and greatest probability of having highest net benefit, but there is considerable uncertainty between DOACs. A head-to-head apixaban versus dabigatran trial may be of value.

Cost-Effectiveness of Left Atrial Appendage Closure for Stroke Reduction in Atrial Fibrillation: Analysis of Pooled, 5-Year, Long-Term Data

Background Recent publications reached conflicting conclusions about the cost-effectiveness of left atrial appendage closure (LAAC) with the Watchman device (Boston Scientific, Marlborough, MA) for stroke risk reduction in nonvalvular atrial fibrillation (AF). This analysis sought to assess the cost-effectiveness of LAAC relative to both warfarin and nonwarfarin oral anticoagulants (NOACs) using pooled, long-term data from the randomized PROTECT AF (Watchman Left Atrial Appendage System for Embolic Protection in Patients With Atrial Fibrillation) and PREVAIL (Prospective Randomized Evaluation of the Watchman LAA Closure Device in Patients With Atrial Fibrillation Versus Long-Term Warfarin) trials. Methods and Results A Markov model was constructed from a US payer perspective with a lifetime (20-year) horizon. LAAC clinical event rates and stroke outcomes were from pooled PROTECT AF and PREVAIL trial 5-year data. Warfarin and NOAC inputs were derived from published meta-analyses. The model was populated with a cohort of 10 000 patients, aged 70 years, at moderate stroke and bleeding risk. Sensitivity analyses were performed. LAAC was cost-effective relative to warfarin by year 7 ($48 674/quality-adjusted life-year) and dominant (more effective and less costly) by year 10. LAAC became cost-effective and dominant compared with NOACs by year 5. Over a lifetime, LAAC provided 0.60 more quality-adjusted life-years than warfarin and 0.29 more than NOACs. In sensitivity analyses, LAAC was cost-effective relative to warfarin and NOACs in 98% and 95% of simulations, respectively. Conclusions Using pooled, 5-year PROTECT AF and PREVAIL trial data, LAAC proved to be not only cost-effective, but cost saving relative to warfarin and NOACs. LAAC with the Watchman device is an economically viable stroke risk reduction strategy for patients with AF seeking an alternative to lifelong anticoagulation.

Cost of Healthcare Associated With Deep Vein Thrombosis in Patients Treated With Warfarin in Turkey: 2010-2013 Database Analysis of a Tertiary Care Center

OBJECTIVES

To evaluate the cost of healthcare with respect to the quality of anticoagulation in patients with deep vein thrombosis (DVT) treated with warfarin in daily practice via the database analysis of a tertiary care center in the period 2010 to 2013.

METHODS

Of 258 307 records in total, 42 582 unique patients with DVT and 32 012 patients with international normalized ratio (INR) measurements were included. Overall, 6720 unique patients with DVT diagnosis and one or more INR measurements were identified, and the records of 4377 out of 6720 unique patients were validated and included in the analysis data set. The cost analysis was based on direct medical costs from the payer's perspective. Cost items were related to healthcare resource utilization (inpatient and outpatient services) during the study period, which provided a basis for calculation of per-patient, outpatient, inpatient, and total direct medical costs.

RESULTS

Mean outpatient, inpatient, and total hospital admission costs were $578, $2195, and $2785, respectively, for patients with time in the therapeutic range of 70% or more, whereas the same costs were $571, $2163, and $3192, respectively, for patients with time in the therapeutic range of less than 70%.

CONCLUSIONS

Our findings for a retrospective cohort of patients with DVT undergoing warfarin therapy reveal that patients spent 70% or more, as opposed to less than 70%, of follow-up time within the therapeutic INR range and that outpatient care, as opposed to inpatient care, was associated with lower healthcare costs. Given the significant contribution that hospital stay makes to the cost burden of DVT, our findings also highlight the association between poor warfarin anticoagulant control and increased hospitalization costs.

Cost-effectiveness analysis of short-duration dual antiplatelet therapy with newer drug-eluting stent platforms versus longer-duration dual antiplatelet therapy with a second-generation drug-eluting stent in elective percutaneous coronary intervention

BACKGROUND

The cost-effectiveness of newer drug-eluting stents (DES) such as biodegradable-polymer or polymer-free stents with shorter dual antiplatelet therapy (DAPT) duration is unknown. We evaluated the cost-effectiveness of treatment with newer DES that may allow for shorter DAPT duration.

PATIENTS AND METHODS

We performed a cost-effectiveness analysis of treatment with newer DES platforms followed by 1 or 3 months of DAPT compared with standard second-generation DES followed by 6 or 12 months of DAPT in patients with stable coronary disease. A Markov model simulated distinct health states over a lifetime. Probabilistic sensitivity analysis and one-way sensitivity analyses were performed. A high-risk bleeding scenario was also evaluated.

RESULTS

Among patients with typical bleeding risk, second-generation DES and 6 months of DAPT was less expensive and resulted in marginally higher quality-adjusted life years compared with other strategies. A newer DES platform and 3 months of DAPT was preferred when the risk of fatal bleeding was two times greater than baseline, or when bleeding increased long-term mortality by a factor of 1.5. In a probabilistic sensitivity analysis, second-generation DES and 6 months of DAPT was preferred in 58% of iterations, whereas in a high-risk bleeding patient scenario, a newer DES and 3 months of DAPT was preferred in 52% of iterations.

CONCLUSION

A DES that allows 3 months of DAPT without increasing stent-related events is likely to be cost-effective among patients at elevated risk of bleeding, but not in patients with average bleeding risk.

Effect of Variation in Published Stroke Rates on the Net Clinical Benefit of Anticoagulation for Atrial Fibrillation

BACKGROUND

Stroke rates in patients with nonvalvular atrial fibrillation (AF) who are not receiving anticoagulant therapy vary widely across published studies; the resulting effect on the net clinical benefit of anticoagulation in AF is unknown.

OBJECTIVE

To determine the effect of variation in published AF stroke rates on the net clinical benefit of anticoagulation.

DESIGN

Markov model decision analysis. Warfarin was the base case, and non-vitamin K antagonist oral anticoagulants (NOACs) were modeled in a secondary analysis.

SETTING

Community-dwelling adults.

PATIENTS

33 434 adults with incident AF.

MEASUREMENTS

Quality-adjusted life-years (QALYs).

RESULTS

Of the 33 434 patients, 27 179 had a CHA2DS2-VASc (congestive heart failure, hypertension, age, diabetes, stroke, and vascular disease) score of 2 or more. The population benefit of warfarin anticoagulation for these patients was least using stroke rates from the ATRIA (AnTicoagulation and Risk Factors In Atrial Fibrillation) study and greatest using those from the Danish National Patient Registry (6290 QALYs [95% CI, ±2.3%] vs. 24 110 QALYs [CI, ±1.9%]; P < 0.001). The optimal CHA2DS2-VASc score threshold for anticoagulation was 3 or more using stroke rates from ATRIA, 2 or more using those from the Swedish AF cohort study, 1 or more using those from the SPORTIF (Stroke Prevention using ORal Thrombin Inhibitor in atrial Fibrillation) study, and 0 or more using those from the Danish National Patient Registry. Accounting for lower rates of NOAC-associated intracranial hemorrhage decreased optimal CHA2DS2-VASc score thresholds, but these thresholds still varied widely.

LIMITATION

Measured benefit may not generalize to other populations.

CONCLUSION

Variation in published AF stroke rates for patients not receiving anticoagulant therapy results in multifold variation in the net clinical benefit of anticoagulation. Guidelines should better reflect the uncertainty in current thresholds of stroke risk score for recommending anticoagulation.

PRIMARY FUNDING SOURCE

None.

Comparative Clinical Outcomes of Edoxaban in Adults With Nonvalvular Atrial Fibrillation

BACKGROUND

A critical appraisal of all pooled evidence regarding novel oral anticoagulants (NOACs) for stroke prevention regardless of publication status or study design has not been conducted yet. Being the latest addition to NOACs, the data on edoxaban are especially scarce.

STUDY QUESTION

What are the comparative clinical outcomes of edoxaban versus warfarin and other NOACs apixaban, dabigatran, or rivaroxaban in adults with nonvalvular atrial fibrillation?

DATA SOURCES

Randomized controlled trials (RCTs), observational studies, and network meta-analyses were identified in PubMed, EMBASE, the Cochrane Library, Pharmapendium, Elsevier Clinical Pharmacology, and the clinicaltrials.gov trial registry in June 2018.

STUDY DESIGN

Rapid review per a priori developed protocol, direct frequentist random-effects meta-analysis of aggregate data, grading the quality of evidence per the Grading of Recommendations Assessment, Development and Evaluation working group approach.

RESULTS

Direct 4 RCTs (23,021 patients) suggest that edoxaban is noninferior to warfarin in prevention of stroke and systemic embolism [pooled relative risk (RR): 0.65, 95% confidence interval (CI): 0.23-1.81, 2 RCTs] and reduces the risk of cardiovascular mortality (RR: 0.87, 95% CI: 0.78-0.97, 1 RCT), major cardiovascular morbidity (RR: 0.90, 95% CI: 0.82-0.98, 2 RCTs), and major bleeding events (RR: 0.80, 95% CI: 0.71-0.91, 1 RCT) but increases the risk of gastrointestinal bleeding (RR: 1.21, 95% CI: 1.01-1.46, 1 RCT) and anemia (RR: 1.45, 95% CI: 1.05-1.99, 3 RCTs). Edoxaban is superior to warfarin in patients with increased risk of bleeding with warfarin because of variants in CYP2C9 and VKORC1 genes. Indirect evidence does not allow valid conclusions regarding comparative superiority of NOACs. The quality of evidence was downgraded because of reporting bias, small number of events, and indirectness in comparisons.

CONCLUSIONS

Edoxaban is a welcome addition to the NOAC's armamentarium. However, the comparative data with other novel NOACs are mostly nonexisting, and urgently needed for better individual patient assessment.

Methodologic Differences Across Studies of Patients With Atrial Fibrillation Lead to Varying Estimates of Stroke Risk

BACKGROUND

Guidelines for anticoagulation in atrial fibrillation (AF) assume that stroke risk scheme point scores correspond to fixed stroke rates. However, reported stroke rates vary widely across AF cohort studies, including studies from the same country. Reasons for this variation are unclear. This study compares methodologies used to assemble and analyze large AF cohorts worldwide and assesses potential bias in estimating stroke rates.

METHODS AND RESULTS

From a previous systematic review of AF cohorts, we analyzed studies including at least 5000 patients. We assessed methods used to generate rates of ischemic stroke off anticoagulants, according to a structured inventory of database interrogation methods. Nine studies (497 578 total patients) met our criteria. Overall cohort stroke rates ranged from 0.45% to 7.03% per year. In bivariate study-level analysis, multiple features were associated with higher stroke rates, including AF identified as inpatients versus outpatients (rate ratio 2.60, 95% confidence interval, 1.19, 5.68), and lack of clinical validation of outcome events (rate ratio 4.09, 95% confidence interval, 1.06, 15.70). European studies reported rates more than 4-fold higher than North American studies. International Classification of Diseases (ICD) coding schemes for outcomes varied widely. Multiple high rate features coexisted in the same studies.

CONCLUSIONS

Among AF cohort studies, differences in the composition, method of assembly, determination of clinical features and outcomes, and analytic approach were strongly associated with reported stroke rates. Our study highlights the need for standardized and validated methodologies for AF cohort assembly and analysis to generate accurate stroke rates to better support anticoagulation guidelines for patients with AF.

Oral anticoagulants for primary prevention, treatment and secondary prevention of venous thromboembolic disease, and for prevention of stroke in atrial fibrillation: systematic review, network meta-analysis and cost-effectiveness analysis

BACKGROUND

Warfarin is effective for stroke prevention in atrial fibrillation (AF), but anticoagulation is underused in clinical care. The risk of venous thromboembolic disease during hospitalisation can be reduced by low-molecular-weight heparin (LMWH): warfarin is the most frequently prescribed anticoagulant for treatment and secondary prevention of venous thromboembolism (VTE). Warfarin-related bleeding is a major reason for hospitalisation for adverse drug effects. Warfarin is cheap but therapeutic monitoring increases treatment costs. Novel oral anticoagulants (NOACs) have more rapid onset and offset of action than warfarin, and more predictable dosing requirements.

OBJECTIVE

To determine the best oral anticoagulant/s for prevention of stroke in AF and for primary prevention, treatment and secondary prevention of VTE.

DESIGN

Four systematic reviews, network meta-analyses (NMAs) and cost-effectiveness analyses (CEAs) of randomised controlled trials.

SETTING

Hospital (VTE primary prevention and acute treatment) and primary care/anticoagulation clinics (AF and VTE secondary prevention).

PARTICIPANTS

Patients eligible for anticoagulation with warfarin (stroke prevention in AF, acute treatment or secondary prevention of VTE) or LMWH (primary prevention of VTE).

INTERVENTIONS

NOACs, warfarin and LMWH, together with other interventions (antiplatelet therapy, placebo) evaluated in the evidence network.

MAIN OUTCOME MEASURES

Efficacy Stroke, symptomatic VTE, symptomatic deep-vein thrombosis and symptomatic pulmonary embolism. Safety Major bleeding, clinically relevant bleeding and intracranial haemorrhage. We also considered myocardial infarction and all-cause mortality and evaluated cost-effectiveness.

DATA SOURCES

MEDLINE and PREMEDLINE In-Process & Other Non-Indexed Citations, EMBASE and The Cochrane Library, reference lists of published NMAs and trial registries. We searched MEDLINE and PREMEDLINE In-Process & Other Non-Indexed Citations, EMBASE and The Cochrane Library. The stroke prevention in AF review search was run on the 12 March 2014 and updated on 15 September 2014, and covered the period 2010 to September 2014. The search for the three reviews in VTE was run on the 19 March 2014, updated on 15 September 2014, and covered the period 2008 to September 2014.

REVIEW METHODS

Two reviewers screened search results, extracted and checked data, and assessed risk of bias. For each outcome we conducted standard meta-analysis and NMA. We evaluated cost-effectiveness using discrete-time Markov models.

RESULTS

Apixaban (Eliquis^®, Bristol-Myers Squibb, USA; Pfizer, USA) [5 mg bd (twice daily)] was ranked as among the best interventions for stroke prevention in AF, and had the highest expected net benefit. Edoxaban (Lixiana^®, Daiichi Sankyo, Japan) [60 mg od (once daily)] was ranked second for major bleeding and all-cause mortality. Neither the clinical effectiveness analysis nor the CEA provided strong evidence that NOACs should replace postoperative LMWH in primary prevention of VTE. For acute treatment and secondary prevention of VTE, we found little evidence that NOACs offer an efficacy advantage over warfarin, but the risk of bleeding complications was lower for some NOACs than for warfarin. For a willingness-to-pay threshold of > £5000, apixaban (5 mg bd) had the highest expected net benefit for acute treatment of VTE. Aspirin or no pharmacotherapy were likely to be the most cost-effective interventions for secondary prevention of VTE: our results suggest that it is not cost-effective to prescribe NOACs or warfarin for this indication.

CONCLUSIONS

NOACs have advantages over warfarin in patients with AF, but we found no strong evidence that they should replace warfarin or LMWH in primary prevention, treatment or secondary prevention of VTE.

LIMITATIONS

These relate mainly to shortfalls in the primary data: in particular, there were no head-to-head comparisons between different NOAC drugs.

FUTURE WORK

Calculating the expected value of sample information to clarify whether or not it would be justifiable to fund one or more head-to-head trials.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005324, CRD42013005331 and CRD42013005330.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Cost-effectiveness Analysis of Intraoperative Cell Salvage for Obstetric Hemorrhage

BACKGROUND

Cost-effectiveness analyses on cell salvage for cesarean delivery to inform national and societal guidelines on obstetric blood management are lacking. This study examined the cost-effectiveness of cell salvage strategies in obstetric hemorrhage from a societal perspective.

METHODS

Markov decision analysis modeling compared the cost-effectiveness of three strategies: use of cell salvage for every cesarean delivery, cell salvage use for high-risk cases, and no cell salvage. A societal perspective and lifetime horizon was assumed for the base case of a 26-yr-old primiparous woman presenting for cesarean delivery. Each strategy integrated probabilities of hemorrhage, hysterectomy, transfusion reactions, emergency procedures, and cell salvage utilization; utilities for quality of life; and costs at the societal level. One-way and Monte Carlo probabilistic sensitivity analyses were performed. A threshold of $100,000 per quality-adjusted life-year gained was used as a cost-effectiveness criterion.

RESULTS

Cell salvage use for cases at high risk for hemorrhage was cost-effective (incremental cost-effectiveness ratio, $34,881 per quality-adjusted life-year gained). Routine cell salvage use for all cesarean deliveries was not cost-effective, costing $415,488 per quality-adjusted life-year gained. Results were not sensitive to individual variation of other model parameters. The probabilistic sensitivity analysis showed that at the $100,000 per quality-adjusted life-year gained threshold, there is more than 85% likelihood that cell salvage use for cases at high risk for hemorrhage is favorable.

CONCLUSIONS

The use of cell salvage for cases at high risk for obstetric hemorrhage is economically reasonable; routine cell salvage use for all cesarean deliveries is not. These findings can inform the development of public policies such as guidelines on management of obstetric hemorrhage.

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.

Dabigatran versus rivaroxaban for the prevention of stroke and systemic embolism in atrial fibrillation in Canada

Canadian patients with atrial fibrillation (AF) in whom anticoagulation is appropriate have two new choices for anticoagulation for prevention of stroke and systemic embolism – dabigatran etexilate (dabigatran) and rivaroxaban. Based on the RE-LY and ROCKET AF trial results, we investigated the cost-effectiveness of dabigatran (twice daily dosing of 150 mg or 110 mg based on patient age) versus rivaroxaban from a Canadian payer perspective. A formal indirect treatment comparison (ITC) of dabigatran versus rivaroxaban was performed, using dabigatran clinical event rates from RE-LY for the safety-on-treatment population, adjusted to the ROCKET AF population. A previously described Markov model was modified to simulate anticoagulation treatment using ITC results as inputs. Model outputs included total costs, event rates, and quality-adjusted life-years (QALYs). The ITC found when compared to rivaroxaban, dabigatran had a lower risk of intracranial haemorrhage (ICH) (relative risk [RR] = 0.38; 95% confidence interval [CI] 0.21 –0.67) and stroke (RR = 0.62; 95%CI 0.45–0.87). Over a lifetime horizon, the model found dabigatran-treated patients experienced fewer ICHs (0.33 dabigatran vs. 0.71 rivaroxaban) and ischaemic strokes (3.40 vs. 3.96) per 100 patient-years, and accrued more QALYs (6.17 vs. 6.01). Dabigatran-treated patients had lower acute care and long-term follow-up costs per patient ($52,314 vs. $53,638) which more than offset differences in drug costs ($7,299 vs. $6,128). In probabilistic analysis, dabigatran had high probability of being the most cost-effective therapy at common thresholds of willingness-to-pay (93% at a $20,000/QALY threshold). This study found dabigatran is economically dominant versus rivaroxaban for prevention of stroke and systemic embolism among Canadian AF patients.

Potential net clinical benefit of population-wide implementation of apixaban and dabigatran among European patients with atrial fibrillation

Vitamin K antagonists (e.g. warfarin) are commonly underutilised, due to limitations such as the need for monitoring, in high-risk atrial fibrillation (AF) patients. We therefore aimed to model the potential impact on clinical outcomes in patients with AF with the use of the novel oral anticoagulant (OAC) drugs, apixaban and dabigatran. We identified all high-risk (CHA2DS2-VASc score ≥2) patients with non-valvular AF and known one-year follow-up from the EuroHeart Survey on AF (EHS-AF). We modelled the expected numbers of clinical events on the novel OACs using published hazard ratios from their respective phase 3 clinical trials and calculated the numbers needed to treat and the mathematical net clinical benefit. Our analysis included 3,400 patients [39% females; mean (SD) age 67 (12) years; CHA2DS2-VASc score 3.0 (1.8)] of which 330 were excluded from the modelling analysis due to concomitant use of OAC and antiplatelet drugs. During one-year follow- up, 108 (3.2%) patients experienced thromboembolism, 51 (1.5%) major bleeds and 146 (4.3%) died. Compared to current treatments (i.e. warfarin, aspirin or nothing) the use of apixaban in highrisk patients would have potentially prevented an additional 17 deaths, 27 strokes and eight major bleeds within this cohort. With use of dabigatran 150 mg BID, 34 strokes could have been prevented and for dabigatran110 mg BID, 16 strokes and six major bleeds would be avoided. Extrapolation of the data from the EHS-AF to the whole of Europe would translate into the prevention of an additional 64,573 major cardiovascular events and deaths each year among patients with a CHA2DS2-VASc ≥2, by the use of apixaban, 43,235 with the use of dabigatran 150 mg bid and 27,272 with the use of dabigatran 110 mg bid. In conclusion, based on this modelling exercise, the utilisation of apixaban and dabigatran for thromboprophylaxis could provide a profound annual mathematical net clinical benefit on stroke and major bleeds, in European AF patients.

Note: The editorial process for this paper was fully handled by Prof. C. Weber, Editor in Chief.

Rivaroxaban vs Warfarin Sodium in the Ultra-Early Period After Atrial Fibrillation-Related Mild Ischemic Stroke: A Randomized Clinical Trial

Importance

In atrial fibrillation (AF)-related acute ischemic stroke, the optimal oral anticoagulation strategy remains unclear.

Objective

To test whether rivaroxaban or warfarin sodium is safer and more effective for preventing early recurrent stroke in patients with AF-related acute ischemic stroke.

Design, Setting, and Participants

A randomized, multicenter, open-label, blinded end point evaluation, comparative phase 2 trial was conducted from April 28, 2014, to December 7, 2015, at 14 academic medical centers in South Korea among patients with mild AF-related stroke within the previous 5 days who were deemed suitable for early anticoagulation. Analysis was performed on a modified intent-to-treat basis.

Interventions

Participants were randomized 1:1 to receive rivaroxaban, 10 mg/d for 5 days followed by 15 or 20 mg/d, or warfarin with a target international normalized ratio of 2.0-3.0, for 4 weeks.

Main Outcomes and Measures

The primary end point was the composite of new ischemic lesion or new intracranial hemorrhage seen on results of magnetic resonance imaging at 4 weeks. Primary analysis was performed in patients who received at least 1 dose of study medications and completed follow-up magnetic resonance imaging. Key secondary end points were individual components of the primary end point and hospitalization length.

Results

Of 195 patients randomized, 183 individuals (76 women and 107 men; mean [SD] age, 70.4 [10.4] years) completed magnetic resonance imaging follow-up and were included in the primary end point analysis. The rivaroxaban group (n = 95) and warfarin group (n = 88) showed no differences in the primary end point (47 [49.5%] vs 48 [54.5%]; relative risk, 0.91; 95% CI, 0.69-1.20; P = .49) or its individual components (new ischemic lesion: 28 [29.5%] vs 31 of 87 [35.6%]; relative risk, 0.83; 95% CI, 0.54-1.26; P = .38; new intracranial hemorrhage: 30 [31.6%] vs 25 of 87 [28.7%]; relative risk, 1.10; 95% CI, 0.70-1.71; P = .68). Each group had 1 clinical ischemic stroke, and all new intracranial hemorrhages were asymptomatic hemorrhagic transformations. Hospitalization length was reduced with rivaroxaban compared with warfarin (median, 4.0 days [interquartile range, 2.0-6.0 days] vs 6.0 days [interquartile range, 4.0-8.0]; P < .001).

Conclusions and Relevance

In mild AF-related acute ischemic stroke, rivaroxaban and warfarin had comparable safety and efficacy.

Trial Registration

clinicaltrials.gov Identifier: NCT02042534.

Clinical and Cost Effectiveness of Apixaban Compared to Aspirin in Patients with Atrial Fibrillation: An Australian Perspective

OBJECTIVE

To determine the clinical and cost effectiveness of apixaban compared to aspirin in the prevention of thromboembolic events for patients with atrial fibrillation for whom vitamin K antagonist (VKA) therapy (warfarin) has been considered unsuitable.

METHODS

A previously published Markov model with yearly cycles was updated. Information from the Apixaban Versus Acetylsalicylic acid to prevent Stroke in Atrial Fibrillation (AVERROES) trial in combination with other population data was used to simulate the costs and effects of apixaban compared to aspirin over 10 years. The model comprised five health states. Costs from an Australian healthcare perspective were estimated from published sources for the year 2015. The main outcome of interest was number needed to treat (NNT), number needed to harm (NNH), the incremental cost-effectiveness ratio (ICER) [cost per quality-adjusted life-year (QALY) gained, and cost per year of life saved (YoLS)]. Costs and benefits were discounted at 5.0 % per annum.

RESULTS

For each patient followed up over 10 years, NNT to prevent one additional event (thromboembolic event, death) for apixaban compared to aspirin was 4.6 and 11.8, respectively. NNH was 35.9 for non-fatal major bleeding. The model predicted that compared to aspirin, apixaban would lead to 0.33 YoLS (discounted) and 0.29 QALYs gained (discounted), at an incremental cost of AUD$1996 (discounted). This resulted in ICERs of AUD$6011 per YoLS and AUD$6929 per QALY gained. In the sensitivity analyses, ICERs were most sensitive to efficacy measures derived from the AVERROES study, and time frame.

CONCLUSION

Compared to aspirin, apixaban is likely to be cost effective in preventing thromboembolic disease among VKA unsuitable patients with atrial fibrillation.

Cardioembolic Stroke

Cardiac embolism accounts for an increasing proportion of ischemic strokes and might multiply several-fold during the next decades. However, research points to several potential strategies to stem this expected rise in cardioembolic stroke. First, although one-third of strokes are of unclear cause, it is increasingly accepted that many of these cryptogenic strokes arise from a distant embolism rather than in situ cerebrovascular disease, leading to the recent formulation of embolic stroke of undetermined source as a distinct target for investigation. Second, recent clinical trials have indicated that embolic stroke of undetermined source may often stem from subclinical atrial fibrillation, which can be diagnosed with prolonged heart rhythm monitoring. Third, emerging evidence indicates that a thrombogenic atrial substrate can lead to atrial thromboembolism even in the absence of atrial fibrillation. Such an atrial cardiomyopathy may explain many cases of embolic stroke of undetermined source, and oral anticoagulant drugs may prove to reduce stroke risk from atrial cardiomyopathy given its parallels to atrial fibrillation. Non-vitamin K antagonist oral anticoagulant drugs have recently expanded therapeutic options for preventing cardioembolic stroke and are currently being tested for stroke prevention in patients with embolic stroke of undetermined source, including specifically those with atrial cardiomyopathy. Fourth, increasing appreciation of thrombogenic atrial substrate and the common coexistence of cardiac and extracardiac stroke risk factors suggest benefits from global vascular risk factor management in addition to anticoagulation. Finally, improved imaging of ventricular thrombus plus the availability of non-vitamin K antagonist oral anticoagulant drugs may lead to better prevention of stroke from acute myocardial infarction and heart failure.

Potential Causes and Implications of Low Target Therapeutic Ratio in Warfarin-Treated Patients for Thrombosis Prophylaxis: A Single-Center Experience

Time in therapeutic range (TTR) of international normalized ratio is crucial for the safety and efficacy of anticoagulation with warfarin and it is influenced by many factors. There are limited data about the quality of warfarin therapy and its effects on clinical outcomes in Turkey. The aim of this study is to demonstrate the quality of anticoagulant therapy with warfarin and evaluate the parameters that affect the quality of warfarin therapy. A total of 170 patients with atrial fibrillation (AF; mean age: 62.2 ± 13.3; 69.2% female) treated with warfarin were included in this study. The mean follow-up period was 20 ± 8.4 months. The mean TTR levels of all patients were found to be 54.2% ± 21.4%. The TTR levels were similar in patients with valvular AF (VAF) and nonvalvular AF (NVAF). Logistic regression analysis revealed that elderly, heart failure (HF), and renal dysfunction were independent predictors of lower TTR. There were no significant differences between the VAF and NVAF subgroups regarding the incidence of mortality, stroke, and myocardial infarction. Cox regression analysis revealed that HF, coronary artery disease, and renal dysfunction were independent predictors of clinical outcomes in addition to lower TTR. Our results provide data regarding the quality of anticoagulation with warfarin from a single tertiary center in Istanbul, Turkey. The questions remain in seeking quality improvement in anticoagulation.

Wide Variation in Reported Rates of Stroke Across Cohorts of Patients With Atrial Fibrillation

Background:

Oral anticoagulants decrease ischemic stroke rates in patients with atrial fibrillation (AF) but increase the risk of bleeding. For the average patient with AF, the threshold of annual ischemic stroke rate where the benefit of anticoagulation outweighs the bleeding risk (net clinical benefit) has been shown to be ≈1% to 2%. Guideline recommendations for oral anticoagulants in AF are based on the CHA 2 DS 2 -VASc stroke risk point scores, assuming that those scores translate to fixed stroke rates. However, the relationship between stroke point scores and annual stroke rates may vary substantially across populations. We sought to comprehensively assess the reported rates of stroke in patients with AF and the relationship of stroke rates to stroke risk point scores.

Methods:

A systematic review of cohort studies and randomized controlled trials enrolled patients with nonvalvular AF not treated with oral anticoagulants.

Results:

Of the 3552 studies screened, we identified 34 studies eligible for analysis. Overall stroke rates in cohort studies were highly heterogeneous (Q=5706.54, P <0.001; I 2 = 99.6%) and ranged from 0.45% to 9.28% per year, despite being of similar objective study quality. The mean North American stroke rate was less than one-third that of the mean European stroke rate ( P <0.0001). However, a random effects regression indicated that between-study variability was not significantly accounted for by cohort region, prospective versus retrospective design, calendar year of study, or outcome event cluster. At a CHA 2 DS 2 -VASc score of 1, 76% of cohorts reported ischemic stroke rates <1% per year and only 18% of cohorts reported a stroke rate >2% per year. At a CHA 2 DS 2 -VASc score of 2, 27% of cohorts reported stroke rates below 1% per year, 40% reported stroke rates between 1 and 2% per year, and 33% reported stroke rates >2% per year.

Conclusions:

Substantial variation exists across cohorts in overall stroke rates and rates corresponding to CHA 2 DS 2 -VASc point scores. These variations can affect the point score threshold for recommending oral anticoagulants in AF. The majority of cohorts did not observe stroke rates that would indicate a clear expected net clinical benefit for anticoagulating AF patients with CHA 2 DS 2 -VASc scores of 1 or 2.

Use of Oral Anticoagulant Therapy in Older Adults with Atrial Fibrillation After Acute Ischemic Stroke

OBJECTIVES

To explore barriers to anticoagulation in older adults with atrial fibrillation (AF) at high risk of stroke and to identify opportunities for interventions that might increase use of oral anticoagulants (OACs).

DESIGN

Retrospective cohort study.

SETTING

Two large community-based AF cohorts.

PARTICIPANTS

Individuals with ischemic stroke surviving hospitalization (N = 1,405, mean age 79).

MEASUREMENTS

Using structured chart review, reasons for nonuse of OAC were identified, and 1-year poststroke survival was assessed. Logistic regression was used to identify correlates of OAC nonuse.

RESULTS

Median CHA₂ DS₂ -VASc score was 5, yet 44% of participants were not prescribed an OAC at discharge. The most-frequent (nonmutually exclusive) physician reasons for not prescribing OAC included fall risk (26.7%), poor prognosis (19.3%), bleeding history (17.1%), participant or family refusal (14.9%), older age (11.0%), and dementia (9.4%). Older age (odds ratio (OR) = 8.96, 95% confidence interval (CI) = 5.01-16.04 for aged ≥85 vs <65) and disability (OR = 12.58, 95% CI = 5.82-27.21 for severe vs no deficit) were the most-important independent predictors of nonuse of OACs. By 1 year, 42.5% of those not receiving an OAC at discharge had died, versus 19.1% of those receiving an OAC (P < .001), far higher than recurrent stroke rates.

CONCLUSION

Despite very high stroke risk, more than 40% of participants were not discharged with an OAC. Dominant reasons included fall risk, poor prognosis, older age, and dementia. These individuals' high 1-year mortality rate confirmed their high level of comorbidity. To improve anticoagulation decisions and outcomes in this population, future research should focus on strategies to mitigate fall risk, improve assessment of risks and benefits of anticoagulation in individuals with AF, and determine whether newer anticoagulants are safer in complex elderly and frail individuals.

Results of a Regional Effort to Improve Warfarin Management

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Improving stroke prevention therapy for patients with atrial fibrillation in primary care: protocol for a pragmatic, cluster-randomized trial

Background

The prevalence of atrial fibrillation (AF) is growing as the population ages, and at least 15% of ischemic strokes are attributed to AF. However, many high-risk AF patients are not offered guideline-recommended stroke prevention therapy due to a variety of system, provider, and patient-level barriers.

Methods

We will conduct a pragmatic, cluster-randomized controlled trial randomizing primary care clinics to test a “toolkit” of quality improvement interventions in primary care. In keeping with the recommendations of the chronic care model to simultaneously activate patients and facilitate proactive care by providers, the toolkit includes provider-focused strategies (education, audit and feedback, electronic decision support, and reminders) plus patient-directed strategies (educational letters and reminders). The trial will include two feedback cycles at baseline and approximately 6 months and a final data collection at approximately 12 months. The study will be powered to show a difference of 10% in the primary outcome of proportion of patients receiving guideline-recommended stroke prevention therapy. Analysis will follow the intention-to-treat principle and will be blind to treatment allocation. Unit of analysis will be the patient; models will use generalized estimating equations to account for clustering at the clinical level.

Discussion

Stroke prevention therapy using anticoagulation in patients with AF is known to reduce strokes by two thirds or more in clinical trials, but most studies indicate under-use of this treatment in real-world practice. If the toolkit successfully improves care for patients with AF, stakeholders will be engaged to facilitate broader application to maximize the potential to improve patient outcomes. The intervention toolkit tested in this project could also provide a model to improve quality of care for other chronic cardiovascular conditions managed in primary care.

Trial registration

ClinicalTrials.gov (NCT01927445). Registered August 14, 2014 at https://clinicaltrials.gov/.

Electronic supplementary material

The online version of this article (doi:10.1186/s13012-016-0523-2) contains supplementary material, which is available to authorized users.

2016 Guidelines of the Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology for the management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Both the incidence and prevalence of AF are increasing, and the burden of AF is becoming huge. Many innovative advances have emerged in the past decade for the diagnosis and management of AF, including a new scoring system for the prediction of stroke and bleeding events, the introduction of non-vitamin K antagonist oral anticoagulants and their special benefits in Asians, new rhythm- and rate-control concepts, optimal endpoints of rate control, upstream therapy, life-style modification to prevent AF recurrence, and new ablation techniques. The Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology aimed to update the information and have appointed a jointed writing committee for new AF guidelines. The writing committee members comprehensively reviewed and summarized the literature, and completed the 2016 Guidelines of the Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology for the Management of Atrial Fibrillation. This guideline presents the details of the updated recommendations, along with their background and rationale, focusing on data unique for Asians. The guidelines are not mandatory, and members of the writing committee fully realize that treatment of AF should be individualized. The physician's decision remains most important in AF management.

Cost-effectiveness of non-vitamin K antagonist oral anticoagulants for stroke prevention in patients with atrial fibrillation at high risk of bleeding and normal kidney function

INTRODUCTION

The comparative cost-effectiveness of all oral anticoagulants approved up to date has not been evaluated from the US perspective. The objective of this study was to compare the cost-effectiveness of edoxaban 60mg, apixaban 5mg, dabigatran 150mg, dabigatran 110mg, rivaroxaban 20mg and warfarin in stroke prevention in atrial fibrillation patients at high-risk of bleeding (defined as HAS-BLED score≥3).

MATERIALS AND METHODS

We constructed a Markov state-transition model to evaluate lifetime costs and quality-adjusted life years (QALYs) with each of the six treatments from the perspective of US third-party payers. Probabilities of clinical events were obtained from the RE-LY, ROCKET-AF, ARISTOTLE and ENGAGE AF-TIMI trials; costs were derived from the Healthcare Cost and Utilization Project, and other studies. Because edoxaban is only indicated in patients with creatinine clearance ≤95ml/min, we re-ran our analyses after excluding edoxaban from the analysis.

RESULTS

Treatment with edoxaban 60mg cost $77,565/QALY gained compared to warfarin, and apixaban 5mg cost $108,631/QALY gained compared to edoxaban 60mg. When edoxaban was not included in the analysis, treatment with apixaban 5mg cost $84,128/QALY gained, compared to warfarin. Dabigatran 150mg, dabigatran 110mg and rivaroxaban 20mg were dominated strategies.

CONCLUSIONS

For patients with creatinine clearance between 50 and 95ml/min, apixaban 5mg was the most cost-effective treatment for willingness-to-pay thresholds (WTP) above $115,000/QALY gained, and edoxaban 60mg was cost-effective when the WTP was between $75,000 and $115,000/QALY gained. For patients with creatinine clearance >95ml/min, apixaban 5mg was the most cost-effective treatment for WTP thresholds above $80,000/QALY gained.

Cost Effectiveness of Implantable Cardiac Monitor-Guided Intermittent Anticoagulation for Atrial Fibrillation: An Analysis of the REACT.COM Pilot Study

INTRODUCTION

Anticoagulation guidelines for patients with atrial fibrillation (AF) disregard AF burden. A strategy of targeted anticoagulation with novel oral anticoagulants (NOACs) based on continuous rhythm assessment with an implantable cardiac monitor (ICM) has recently been explored. We evaluated the potential cost-effectiveness of this strategy versus projected outcomes with continuous anticoagulation.

METHODS AND RESULTS

We developed a Markov model using data from the Rhythm Evaluation for AntiCoagulaTion With COntinuous Monitoring (REACT.COM) pilot study (N = 59) and prior NOAC trials to calculate the costs and quality-adjusted life years (QALYs) associated with ICM-guided intermittent anticoagulation for AF versus standard care during a 3-year time horizon. Health state utilities were estimated from the pilot study population using the SF-12. Costs were based on current Medicare reimbursement. Over 14 ± 4 months of follow-up, 18 of 59 patients had 35 AF episodes. The ICM-guided strategy resulted in a 94% reduction in anticoagulant use relative to continuous treatment. There were no strokes, 3 (5.1%) TIAs, 2 major bleeding events (on aspirin) and 3 minor bleeding events with the ICM-guided strategy. The projected total 3-year costs were $12,535 for the ICM-guided strategy versus $13,340 for continuous anticoagulation. Projected QALYs were 2.45 for both groups.

CONCLUSION

Based on a pilot study, a strategy of ICM-guided anticoagulation with NOACs may be cost-saving relative to expected outcomes with continuous anticoagulation, with similar quality-adjusted survival. This strategy could be attractive from a health economic perspective if shown to be safe and effective in a rigorous clinical trial.

The Sex, Age, Medical History, Treatment, Tobacco Use, Race Risk (SAMe TT2R2) Score Predicts Warfarin Control in a Singaporean Population

BACKGROUND

Warfarin reduces stroke risk in atrial fibrillation (AF) patients but requires ongoing monitoring. Time in therapeutic range (TTR) is used as a measure of warfarin control, with a TTR less than 60% associated with adverse patient outcomes. The Sex, Age, Medical history, Treatment, Tobacco use, Race (SAMe-TT₂R₂) score has been identified as a model able to predict warfarin control, but this has been tested in mainly Caucasian populations. Therefore, the aim of this study was to determine the ability of the SAMe-TT₂R₂ score to predict warfarin control in a Singaporean population consisting of Chinese, Malay, and Indian race.

METHODS

Retrospective data were collected from the National Heart Centre Singapore for AF patients receiving warfarin between January and June 2014. The TTR and the SAMe-TT₂R₂ score were calculated for each patient.

RESULTS

The 1137 non-valvular AF patients had a mean TTR of 58.0 ± 34.3% and a median SAMe-TT₂R₂ score of 3. The categorized SAMe-TT₂R₂ scores (2 versus >2) showed a significant reduction in mean TTR for the entire population (63.2% versus 55.8%, P = .0004) and also when categorized according to race for Chinese (62.7% versus 56.9%, P = .0075) and Malay (68.4% versus 50.6%, P = .0131) populations.

CONCLUSION

The SAMe-TT₂R₂ tool is effective in predicting warfarin control in a Singaporean population as patients with a score greater than 2 had poor control. The minimum score for non-Caucasian patients is 2; thus, in these patients, the presence of any additional risk factors identified in the SAMe-TT₂R₂ tool categorizes them as unlikely to achieve adequate warfarin control and possible candidates for alternative anticoagulants.

Impact of Warfarin on Atrial-Fibrillation Outcomes Related to Economic Consumption Patterns: Hospitalization, Cost, and Mortality may be Predictable and Modifiable at the Population Level

INTRODUCTION

Warfarin reduces atrial fibrillation (AF)-related strokes and may impact mortality, hospitalizations, and costs. This study investigated the possibility that patterns of warfarin consumption are associated with the frequency of acute events.

METHODS

Annual cost profiles of 9.2 million Medicare beneficiaries with AF were analyzed to identify patterns of benefits consumption from 2000 through 2010. Beneficiaries were divided into five consumption clusters based upon their annual cost profiles, ranging from crisis consumers at the high end to low consumers. Resource-utilization patterns and outcome differences were calculated between AF beneficiaries who received warfarin and those who did not. Propensity score-matched analysis was performed to reduce selection bias.

RESULTS

The annual percentages of beneficiaries and expenditures that differentiated each cluster showed stable patterns. Warfarin use influenced consumption patterns and outcomes. The most important financial difference between higher and lower consumers was inpatient cost. AF beneficiaries on warfarin had lower annual cost profiles and had a higher propensity to persist in or migrate to consumption clusters with comparatively small reimbursement claims and lower hospitalization risks. AF beneficiaries not on warfarin had higher cost and mortality.

CONCLUSIONS

These data signal that a nontrivial portion of acute events (hospitalization and mortality) are amenable to medical intervention (warfarin). When acute events are amenable to medical intervention and occur at a higher frequency because guidelines have not been applied evenly across affected populations, it is appropriate to define those occurrences as disparities associated with systemic failure in evidence-based medicine. Quality-improvement initiatives that reduce therapeutic disparities may result in lower cost and improved outcomes.

FUNDING

No funding or sponsorship was received for this study or publication of this article.

Cost-effectiveness analysis of left atrial appendage occlusion compared with pharmacological strategies for stroke prevention in atrial fibrillation

BACKGROUND

Transcatheter left atrial appendage occlusion (LAAO) is a promising therapy for stroke prophylaxis in non-valvular atrial fibrillation (NVAF) but its cost-effectiveness remains understudied. This study evaluated the cost-effectiveness of LAAO for stroke prophylaxis in NVAF.

METHODS

A Markov decision analytic model was used to compare the cost-effectiveness of LAAO with 7 pharmacological strategies: aspirin alone, clopidogrel plus aspirin, warfarin, dabigatran 110 mg, dabigatran 150 mg, apixaban, and rivaroxaban. Outcome measures included quality-adjusted life years (QALYs), lifetime costs and incremental cost-effectiveness ratios (ICERs). Base-case data were derived from ACTIVE, RE-LY, ARISTOTLE, ROCKET-AF, PROTECT-AF and PREVAIL trials. One-way sensitivity analysis varied by CHADS2 score, HAS-BLED score, time horizons, and LAAO costs; and probabilistic sensitivity analysis using 10,000 Monte Carlo simulations was conducted to assess parameter uncertainty.

RESULTS

LAAO was considered cost-effective compared with aspirin, clopidogrel plus aspirin, and warfarin, with ICER of US$5,115, $2,447, and $6,298 per QALY gained, respectively. LAAO was dominant (i.e. less costly but more effective) compared to other strategies. Sensitivity analysis demonstrated favorable ICERs of LAAO against other strategies in varied CHADS2 score, HAS-BLED score, time horizons (5 to 15 years) and LAAO costs. LAAO was cost-effective in 86.24 % of 10,000 simulations using a threshold of US$50,000/QALY.

CONCLUSIONS

Transcatheter LAAO is cost-effective for prevention of stroke in NVAF compared with 7 pharmacological strategies. The transcatheter left atrial appendage occlusion (LAAO) is considered cost-effective against the standard 7 oral pharmacological strategies including acetylsalicylic acid (ASA) alone, clopidogrel plus ASA, warfarin, dabigatran 110 mg, dabigatran 150 mg, apixaban, and rivaroxaban for stroke prophylaxis in non-valvular atrial fibrillation management.

Clopidogrel versus aspirin in patients with recent ischemic stroke and established peripheral artery disease: an economic evaluation in a Chinese setting

BACKGROUND AND OBJECTIVES

Clopidogrel or aspirin are indicated for patients with recent ischemic stroke (IS) or established peripheral artery disease (PAD). We compared the cost effectiveness of clopidogrel with that of aspirin in Chinese patients with recent IS or established PAD.

METHODS

A discrete-event simulation was developed to evaluate the economic implications of secondary prevention with clopidogrel versus aspirin. All available evidence was derived from clinical studies. Costs from a Chinese healthcare perspective in 2013 US dollars and quality-adjusted life-years (QALYs) were projected over patients' lifetimes. Uncertainties were addressed using sensitivity analyses.

RESULTS

Compared with aspirin, clopidogrel yielded a marginally increased life expectancy by 0.46 and 0.21 QALYs at an incremental cost-effectiveness ratio of $US5246 and $US9890 per QALY in patients with recent IS and established PAD, respectively. One-way sensitivity analyses showed that the evaluation of patients with PAD and recent IS was robust except for the parameter of patient age. Given a willingness-to-pay of $US19,877 per QALY gained, clopidogrel had a probability of 90 and 68% of being cost effective in the recent IS or established PAD subgroups compared with aspirin, respectively.

CONCLUSIONS

The analysis suggests that clopidogrel for secondary prevention is cost effective for patients with either PAD or recent IS in a Chinese setting in comparison with aspirin.

Physician and Patient Preferences for Nonvalvular Atrial Fibrillation Therapies

OBJECTIVES

The objective of this study was to compare patient and physician preferences for different antithrombotic therapies used to treat nonvalvular atrial fibrillation (NVAF).

METHODS

Patients diagnosed with NVAF and physicians treating such patients completed 12 discrete choice questions comparing NVAF therapies that varied across five attributes: stroke risk, major bleeding risk, convenience (no regular blood testing/dietary restrictions), dosing frequency, and patients' out-of-pocket cost. We used a logistic regression to estimate the willingness-to-pay (WTP) value for each attribute.

RESULTS

The 200 physicians surveyed were willing to trade off $38 (95% confidence interval [CI] $22 to $54] in monthly out-of-pocket cost for a 1% (absolute) decrease in stroke risk, $14 (95% CI $8 to $21) for a 1% decrease in major bleeding risk, and $34 (95% CI $9 to $60) for more convenience. The WTP value among 201 patients surveyed was $30 (95% CI $18 to $42) for reduced stroke risk, $16 (95% CI $9 to $24) for reduced bleeding risk, and -$52 (95% CI -$96 to -6) for convenience. The WTP value for convenience among patients using warfarin was $9 (95% CI $1 to $18) for more convenience, whereas patients not currently on warfarin had a WTP value of -$90 (95% CI -$290 to -$79). Both physicians' and patients' WTP value for once-daily dosing was not significantly different from zero. On the basis of survey results, 85.0% of the physicians preferred novel oral anticoagulants (NOACs) to warfarin. NOACs (73.0%) were preferred among patients using warfarin, but warfarin (78.2%) was preferred among patients not currently using warfarin. Among NOACs, both patients and physicians preferred apixaban.

CONCLUSIONS

Both physicians and patients currently using warfarin preferred NOACs to warfarin. Patients not currently using warfarin preferred warfarin over NOACs because of an apparent preference for regular blood testing/dietary restrictions.

Using Phase-Based Costing of Real-World Data to Inform Decision-Analytic Models for Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) poses a significant economic burden. An increasing number of interventions for AF require cost-effectiveness analysis with decision-analytic modeling to demonstrate value. However, high-quality cost estimates of AF that can be used to inform decision-analytic models are lacking.

OBJECTIVES

The objectives of this study were to determine whether phase-based costing methods are feasible and practical for informing decision-analytic models outside of oncology.

METHODS

Patients diagnosed with AF between 1 January 2003 and 30 June 2011 in Ontario, Canada were identified based on a hospital admission for AF using administrative data housed at the Institute for Clinical Evaluative Sciences. Patient observations were then divided into phases based on clinical events typically used for decision-analytic modeling (i.e., minor stroke/transient ischemic attack [TIA], moderate to severe ischemic stroke, myocardial infarction, extracranial hemorrhage [ECH], intracranial hemorrhage [ICH], multiple events, death from an event, or death from other causes). First 30-day and greater than 30-day costs of healthcare resources in each health state were estimated based on a validated methodology. All costs are reported in 2013 Canadian dollars (Can$) and from a healthcare payer perspective.

RESULTS

Patients (n = 109,002) with AF who did not experience a clinical event incurred costs of Can$1566 per 30 days, on average. The average 30-day cost of experiencing a fatal clinical event was Can$42,871, but the cost of dying from all other causes was much smaller (Can$12,800). The clinical events associated with the highest short-term costs were ICH (Can$22,347) and moderate to severe ischemic stroke (Can$19,937). The lowest short-term costs were due to minor ischemic stroke/TIA (Can$12,515) and ECH (Can$12,261). Patients who had experienced a moderate to severe ischemic stroke incurred the highest long-term costs.

CONCLUSIONS

Real-world Canadian data and a phase-based costing approach were used to estimate short- and long-term costs associated with AF-related major clinical events. The results of this study can also inform decision-analytic models for AF.

Suboptimal Use of Oral Anticoagulants in Atrial Fibrillation: Has the Introduction of Direct Oral Anticoagulants Improved Prescribing Practices?

BACKGROUND AND OBJECTIVES

Atrial fibrillation (AF) and the associated risk of stroke are emerging epidemics throughout the world. Suboptimal use of oral anticoagulants for stroke prevention has been widely reported from observational studies. In recent years, direct oral anticoagulants (DOACs) have been introduced for thromboprophylaxis. We conducted a systematic literature review to evaluate current practices of anticoagulation in AF, pharmacologic features and adoption patterns of DOACs, their impacts on proportion of eligible patients with AF who receive oral anticoagulants, persisting challenges and future prospects for optimal anticoagulation.

LITERATURE SOURCE AND SELECTION CRITERIA

In conducting this review, we considered the results of relevant prospective and retrospective observational studies from real-world practice settings. PubMed (MEDLINE), Scopus (RIS), Google Scholar, EMBASE and Web of Science were used to source relevant literature. There were no date limitations, while language was limited to English. Selection was limited to articles from peer reviewed journals and related to our topic.

RESULTS

Most studies identified in this review indicated suboptimal use of anticoagulants is a persisting challenge despite the availability of DOACs. Underuse of oral anticoagulants is apparent particularly in patients with a high risk of stroke. DOAC adoption trends are quite variable, with slow integration into clinical practice reported in most countries; there has been limited impact to date on prescribing practice.

CONCLUSION

Available data from clinical practice suggest that suboptimal oral anticoagulant use in patients with AF and poor compliance with guidelines still remain commonplace despite transition to a new era of anticoagulation featuring DOACs.

North American Thrombosis Forum, AF Action Initiative Consensus Document

The North American Thrombosis Forum Atrial Fibrillation Action Initiative consensus document is a comprehensive yet practical briefing document focusing on stroke and bleeding risk assessment in patients with atrial fibrillation, as well as recommendations regarding anticoagulation options and management. Despite the breadth of clinical trial data and guideline recommendation updates, many clinicians continue to struggle to synthesize the disparate information available. This problem slows the uptake and utilization of updated risk prediction tools and adoption of new oral anticoagulants. This document serves as a practical and educational reference for the entire medical community involved in the care of patients with atrial fibrillation.

A cost-utility analysis for catheter ablation of atrial fibrillation in combination with warfarin and dabigatran based on the CHADS2 score in Japan

BACKGROUND

We aimed to clarify the cost-effectiveness of an expensive combination therapy for atrial fibrillation (AF) using both catheter ablation and dabigatran compared with warfarin at each CHADS₂ score for patients in Japan.

METHODS

A Markov model was constructed to analyze costs and quality-adjusted life years associated with AF therapeutic options with a time horizon of 10 years. The target population was 60-year-old patients with paroxysmal AF. The indication for anticoagulation was determined according to the Japanese guideline. Anticoagulation-related data were derived from the RE-LY study and the AF recurrence rate was set at 2.7% per month during the first 12 months and at 0.40% per month afterwards. Stroke risk was determined according to AF recurrence, anticoagulation, and CHADS₂ score. The risks for stroke recurrence and stroke death were also considered. Costs were calculated from the healthcare payer's perspective, and only direct medical costs were included.

RESULTS

Warfarin was the most preferred option for patients with a CHADS₂ score of 0 from a health economics aspect. Ablation under warfarin was preferred for a CHADS₂ score of 1-3, while ablation under dabigatran was preferred for a CHADS₂ score ≥4. The quality of life score for AF had the largest impact on the incremental cost-effectiveness ratios in the analysis between the anticoagulation arm and the anticoagulation+ablation arm for a CHADS₂ score of 2. Within the range of the Japanese willingness-to-pay threshold (¥5,000,000), the ablation+warfarin arm became the best option with its probability of 81.7% for a CHADS₂ score of 2; the dabigatran+ablation arm was the most preferred option with its probability of 56.1% for a CHADS₂ score of 4.

CONCLUSIONS

Ablation under dabigatran therapy is an expensive therapeutic option, but it might benefit patients with a low quality of life and a high CHADS₂ score.