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

Which patients with unprovoked venous thromboembolism should receive extended anticoagulation with direct oral anticoagulants? A systematic review, network meta-analysis, and decision analysis

INTRODUCTION

Direct oral anticoagulants (DOACs) effectively prevent recurrent venous thromboembolism (VTE). However, it is unknown which agents should be used to prevent recurrent VTE and which patients with unprovoked VTE should receive extended anticoagulation. We therefore sought to compare the efficacy and safety among DOACs for secondary prevention of VTE. We also determined a risk-adapted threshold for initiating extended anticoagulation based on the likelihood of VTE recurrence (without treatment) and bleeding (with treatment) in patients with unprovoked VTE.

METHODS

Our systematic review of randomized controlled trials compares extended anticoagulation with DOACs to another DOAC, aspirin, or placebo for the prevention of recurrent VTE. We searched PubMed, EMBASE, and Cochrane Registry of Controlled Trials (CENTRAL) in October 2018. Our outcomes of interest were VTE recurrence, major bleeding, and all clinically relevant bleeding. We used network meta-analysis to make indirect comparisons among DOACs. We populated the threshold decision-analytic model with data from our meta-analysis to determine the risk of VTE recurrence above which the benefits of extended anticoagulation outweigh the harms compared with no treatment.

RESULTS

We included four, high-quality, randomized trials comprising 8386 participants. Low-dose apixaban, full-dose apixaban, low-dose rivaroxaban, full-dose rivaroxaban, and dabigatran reduce VTE recurrence compared with placebo (RR = 0.19, 95% CI, 0.12-0.31; RR = 0.20, 95% CI, 0.12-0.32; RR = 0.08, 95% CI, 0.03-0.27; RR = 0.14, 95% CI, 0.06-0.35; RR = 0.19, 95% CI, 0.09-0.40, respectively). No DOACs increased major bleeding risk compared with placebo. A VTE recurrence risk above 0.3% to 0.4% at approximately 1 year is the threshold to treat a patient with unprovoked VTE with extended anticoagulation (with any DOAC).

CONCLUSIONS

All DOACs exhibit comparable efficacy for the prevention of recurrent VTE. Given that the risk of VTE recurrence is much higher than the calculated threshold for treatment, extended thromboprophylaxis should be considered in all patients with unprovoked VTE who do not have increased bleeding risk.

The prescription of direct oral anticoagulants in the elderly: An observational study of 19 798 Ambulatory subjects

OBJECTIVE

Direct oral anticoagulants (DOACs) are increasingly prescribed to elderly people, but the epidemiologic data for this population remains scarce. We compared the elderly population taking DOACs and those not taking DOACs (noDOAC).

METHOD

We included individuals over 75 years old, affiliated to Mutualité Sociale Agricole of Burgundy (a French regional health insurance agency), who had been refunded for a prescribed DOAC between 1st and 30th September 2017. The DAOC group (DAOCG) and noDOAC group (noDOACG) were compared in terms of demographic conditions, registered chronic diseases (RCD), and number and types of prescribed drugs. In the DOACG, we compared the type of prescribing physician and laboratory monitoring for novel prescriptions (initial) and prescription refills (≥ 3 months).

RESULTS

Of the 19 798 included patients, 1518 (7.7%) were prescribed DAOCs and 18 280 (92.3%) were not. Mean and median age was 85 years in the 2 groups (DOACG and noDOACG). In the DOACG, there were more men (50% vs 40.2%), more RCD (88.9% vs 68.7%) and more drugs per prescription (6 ± 2.8 vs 5 ± 2.9) (All P < .01). The DOACG also took more antihypertensive drugs. The most commonly prescribed DOACs were apixaban (42.9%) followed by rivaroxaban (38.4%) and dabigatran (18.6%). Complete blood count, serum creatinine and coagulation function tests were requested for 69.4%, 75% and 22.2%, respectively, of patients prescribed DAOCs.

CONCLUSIONS

The DOACG had more RCD and drugs per prescription than the noDOACG; routine laboratory monitoring was insufficient. What's known Platelet aggregation inhibitors (low-dose) are recommended for secondary prevention of cardiovascular events in patients suffering from symptomatic atherosclerosis. The main risk of this treatment is bleeding. What's new A prescription for platelet aggregation inhibitors was found in 34% of geriatric inpatients in this prospective study. Compliance to guidelines was better for symptomatic peripheral artery disease than for primary prevention in accordance with recent publications. Geriatric comorbidities had no impact on the prescription of platelet aggregation inhibitors. Underuse of platelet aggregation inhibitors was observed in 11.3% of cases and overuse in 13.7% of cases.

Lead-I ECG for detecting atrial fibrillation in patients with an irregular pulse using single time point testing: a systematic review and economic evaluation

BACKGROUND

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and is associated with an increased risk of stroke and congestive heart failure. Lead-I electrocardiogram (ECG) devices are handheld instruments that can be used to detect AF at a single time point in people who present with relevant signs or symptoms.

OBJECTIVE

To assess the diagnostic test accuracy, clinical impact and cost-effectiveness of using single time point lead-I ECG devices for the detection of AF in people presenting to primary care with relevant signs or symptoms, and who have an irregular pulse compared with using manual pulse palpation (MPP) followed by a 12-lead ECG in primary or secondary care.

DATA SOURCES

MEDLINE, MEDLINE Epub Ahead of Print and MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, PubMed, Cochrane Databases of Systematic Reviews, Cochrane Central Database of Controlled Trials, Database of Abstracts of Reviews of Effects and the Health Technology Assessment Database.

METHODS

The systematic review methods followed published guidance. Two reviewers screened the search results (database inception to April 2018), extracted data and assessed the quality of the included studies. Summary estimates of diagnostic accuracy were calculated using bivariate models. An economic model consisting of a decision tree and two cohort Markov models was developed to evaluate the cost-effectiveness of lead-I ECG devices.

RESULTS

No studies were identified that evaluated the use of lead-I ECG devices for patients with signs or symptoms of AF. Therefore, the diagnostic accuracy and clinical impact results presented are derived from an asymptomatic population (used as a proxy for people with signs or symptoms of AF). The summary sensitivity of lead-I ECG devices was 93.9% [95% confidence interval (CI) 86.2% to 97.4%] and summary specificity was 96.5% (95% CI 90.4% to 98.8%). One study reported limited clinical outcome data. Acceptability of lead-I ECG devices was reported in four studies, with generally positive views. The de novo economic model yielded incremental cost-effectiveness ratios (ICERs) per quality-adjusted life-year (QALY) gained. The results of the pairwise analysis show that all lead-I ECG devices generated ICERs per QALY gained below the £20,000-30,000 threshold. Kardia Mobile (AliveCor Ltd, Mountain View, CA, USA) is the most cost-effective option in a full incremental analysis.

LIMITATIONS

No published data evaluating the diagnostic accuracy, clinical impact or cost-effectiveness of lead-I ECG devices for the population of interest are available.

CONCLUSIONS

Single time point lead-I ECG devices for the detection of AF in people with signs or symptoms of AF and an irregular pulse appear to be a cost-effective use of NHS resources compared with MPP followed by a 12-lead ECG in primary or secondary care, given the assumptions used in the base-case model.

FUTURE WORK

Studies assessing how the use of lead-I ECG devices in this population affects the number of people diagnosed with AF when compared with current practice would be useful.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018090375.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Shared parameter model for competing risks and different data summaries in meta-analysis: Implications for common and rare outcomes

This paper considers the problem in aggregate data meta-analysis of studies reporting multiple competing binary outcomes and of studies using different summary formats for those outcomes. For example, some may report numbers of patients with at least one of each outcome while others may report the total number of such outcomes. We develop a shared parameter model on hazard ratio scale accounting for different data summaries and competing risks. We adapt theoretical arguments from the literature to demonstrate that the models are equivalent if events are rare. We use constructed data examples and a simulation study to find an event rate threshold of approximately 0.2 above which competing risks and different data summaries may bias results if no adjustments are made. Below this threshold, simpler models may be sufficient. We recommend analysts to consider the absolute event rates and only use a simple model ignoring data types and competing risks if all of underlying events are rare (below our threshold of approximately 0.2). If one or more of the absolute event rates approaches or exceeds our informal threshold, it may be necessary to account for data types and competing risks through a shared parameter model in order to avoid biased estimates.

Implantable cardiac monitors to detect atrial fibrillation after cryptogenic stroke: a systematic review and economic evaluation

BACKGROUND

Cryptogenic stroke is a stroke for which no cause is identified after standard diagnostic tests. Long-term implantable cardiac monitors may be better at diagnosing atrial fibrillation and provide an opportunity to reduce the risk of stroke recurrence with anticoagulants.

OBJECTIVES

The objectives were to assess the diagnostic test accuracy, clinical effectiveness and cost-effectiveness of three implantable monitors [BioMonitor 2-AF™ (Biotronik SE & Co. KG, Berlin, Germany), Confirm Rx™ (Abbott Laboratories, Lake Bluff, IL, USA) and Reveal LINQ™ (Medtronic plc, Minneapolis, MN, USA)] in patients who have had a cryptogenic stroke and for whom no atrial fibrillation is detected after 24 hours of external electrocardiographic monitoring.

DATA SOURCES

MEDLINE, EMBASE, The Cochrane Library, Database of Abstracts of Reviews of Effects and Health Technology Assessment databases were searched from inception until September 2018.

REVIEW METHODS

A systematic review was undertaken. Two reviewers agreed on studies for inclusion and performed quality assessment using the Cochrane Risk of Bias 2.0 tool. Results were discussed narratively because there were insufficient data for synthesis. A two-stage de novo economic model was developed: (1) a short-term patient flow model to identify cryptogenic stroke patients who have had atrial fibrillation detected and been prescribed anticoagulation treatment (rather than remaining on antiplatelet treatment) and (2) a long-term Markov model that captured the lifetime costs and benefits of patients on either anticoagulation or antiplatelet treatment.

RESULTS

One randomised controlled trial, Cryptogenic Stroke and underlying Atrial Fibrillation (CRYSTAL-AF) (Sanna T, Diener HC, Passman RS, Di Lazzaro V, Bernstein RA, Morillo CA, et al. Cryptogenic stroke and underlying atrial fibrillation. N Engl J Med 2014;370:2478-86), was identified, and no diagnostic test accuracy study was identified. The CRYSTAL-AF trial compared the Reveal™ XT (a Reveal LINQ predecessor) (Medtronic plc) monitor with standard of care monitoring. Twenty-six single-arm observational studies for the Reveal devices were also identified. The only data for BioMonitor 2-AF or Confirm Rx were from mixed population studies supplied by the companies. Atrial fibrillation detection in the CRYSTAL-AF trial was higher with the Reveal XT than with standard monitoring at all time points. By 36 months, atrial fibrillation was detected in 19% of patients with an implantable cardiac monitor and in 2.3% of patients receiving conventional follow-up. The 26 observational studies demonstrated that, even in a cryptogenic stroke population, atrial fibrillation detection rates are highly variable and most cases are asymptomatic; therefore, they probably would not have been picked up without an implantable cardiac monitor. Device-related adverse events, such as pain and infection, were low in all studies. The de novo economic model produced incremental cost effectiveness ratios comparing implantable cardiac monitors with standard of care monitoring to detect atrial fibrillation in cryptogenic stroke patients based on data for the Reveal XT device, which can be related to Reveal LINQ. The BioMonitor 2-AF and Confirm RX were included in the analysis by making a strong assumption of equivalence with Reveal LINQ. The results indicate that implantable cardiac monitors could be considered cost-effective at a £20,000-30,000 threshold. When each device is compared incrementally, BioMonitor 2-AF dominates Reveal LINQ and Confirm RX.

LIMITATIONS

The cost-effectiveness analysis for implantable cardiac monitors is based on a strong assumption of clinical equivalence and should be interpreted with caution.

CONCLUSIONS

All three implantable cardiac monitors could be considered cost-effective at a £20,000-30,000 threshold, compared with standard of care monitoring, for cryptogenic stroke patients with no atrial fibrillation detected after 24 hours of external electrocardiographic monitoring; however, further clinical studies are required to confirm their efficacy in cryptogenic stroke patients.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42018109216.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 5. See the NIHR Journals Library website for further project information.

Cost-effectiveness Evaluations Among the Direct Oral Anticoagulants for the Prevention and Treatment of Venous Thromboembolism: Systematic Review

Venous thromboembolism (VTE) is associated with high recurrence, mortality, and cost burden. Direct oral anticoagulants (DOACs) are currently used for VTE treatment, and they offer more benefits over warfarin, despite being more expensive. There is no consensus on the most cost-effective DOAC agent, especially in VTE. This systematic review aims to summarize the comparative cost-effectiveness studies and their impact among DOACs in the treatment of VTE. Literature systematic review of PubMed, Embase, and EconLit was conducted in February 2018 to identify all cost-effectiveness studies of DOAC for the treatment and prevention of VTE. Two independent investigators systematically collected search results and assessed the quality of the studies. The search identified 7 articles, all of which had dabigatran and rivaroxaban as comparators, 6 of which also included apixaban, and 2 of which also had edoxaban. Results of 3 articles concluded that apixaban is a dominant strategy compared to other DOACs in terms of Incremental Cost-Effectiveness Ratio (ICER) in the treatment and prevention of recurrent VTE. One article compared rivaroxaban and dabigatran, with the latter dominating rivaroxaban in terms of ICER. Compared to other DOACs, 2 articles reported apixaban being associated with highest annual total medical cost avoidance of US$4244 and US$4440 per patient-year (ppy), respectively. One article reported that apixaban had the highest annual total medical cost differences of US$918 ppy compared to other DOACs. This systematic review demonstrates that apixaban is considered a cost-effective strategy for VTE treatment and prevention of recurrent VTE.

A randomised controlled trial of extended anticoagulation treatment versus standard treatment for the prevention of recurrent venous thromboembolism (VTE) and post-thrombotic syndrome in patients being treated for a first episode of unprovoked VTE (the ExACT study)

Venous thromboembolism (VTE) is prevalent and impactful, with a risk of death, morbidity and recurrence. Post-thrombotic syndrome (PTS) is a common consequence and associated with impaired quality of life (QoL). The ExACT study was a non-blinded, prospective, multicentred randomised controlled trial comparing extended versus limited duration anticoagulation following a first unprovoked VTE (proximal deep vein thrombosis or pulmonary embolism). Adults were eligible if they had completed ≥3 months anticoagulation (remaining anticoagulated). The primary outcome was time to first recurrent VTE from randomisation. The secondary outcomes included PTS severity, bleeding, QoL and D-dimers. Two-hundred and eighty-one patients were recruited, randomised and followed up for 24 months (mean age 63, male:female 2:1). There was a significant reduction in recurrent VTE for patients receiving extended anticoagulation [2·75 vs. 13·54 events/100 patient years, adjusted hazard ratio (aHR) 0·20 (95% confidence interval (CI): 0·09 to 0·46, P < 0·001)] with a non-significant increase in major bleeding [3·54 vs. 1·18 events/100 patient years, aHR 2·99 (95% CI: 0·81-11·05, P = 0·10)]. Outcomes of PTS and QoL were no different between groups. D-dimer results (on anticoagulation) did not predict VTE recurrence. In conclusion, extended anticoagulation reduced VTE recurrence but did not reduce PTS or improve QoL and was associated with a non-significant increase in bleeding. Results also suggest very limited clinical utility of D-dimer testing on anticoagulated patients.

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.

Cost-effectiveness of apixaban compared to other anticoagulants in patients with atrial fibrillation in the real-world and trial settings

Introduction

Randomized clinical trials (RCTs) and real-world data (RWD) in patients with atrial fibrillation have shown that—compared to vitamin K antagonists (VKAs)—non-VKA oral anticoagulants (NOACs) are at least as effective in the prevention of ischaemic stroke, while decreasing the risk of bleeding.

Objective

We aim to evaluate the cost-effectiveness of the NOAC apixaban versus other NOACs (dabigatran, edoxaban and rivaroxaban) and VKA, for stroke prevention in patients with atrial fibrillation by including the available data both from RCT and real-world analyses of all NOACs into one integrative previously published model.

Methods

The model was updated to the current Dutch healthcare situation. The incremental cost-effectiveness ratio was calculated using either efficacy/effectiveness and safety data derived from a network meta-analysis (NMA) synthesizing NOAC RCTs or RWD. We conducted a systematic literature search to identify eligible publication to best inform the RWD-based analysis. Additional sensitivity and scenario analyses were conducted to test the robustness of the outcomes.

Results

In the NMA-based analysis, apixaban appeared to be cost-effective compared to VKA (€3,506 per quality adjusted life-year) and dominant (cost-saving and more effective) over dabigatran 110 mg, dabigatran 150 mg, edoxaban and rivaroxaban. In the RWD-based analysis, apixaban was dominant over all other anticoagulants. In the scenario analysis apixaban appeared to be not cost-effective compared to dabigatran 150 mg, when using equal event-unrelated treatment discontinuation rates for each drug. In all other scenarios apixaban is cost-effective or cost-saving compared to VKA and other NOACs.

Conclusion

Based on RCTs as well as RWD, we conclude that apixaban is generally cost-effective or even cost-saving (less costly and more effective) compared to VKA and other NOACs in the overall population of patients with atrial fibrillation.

Identifying mutation-driven changes in gene functionality that lead to venous thromboembolism

Venous thromboembolism (VTE) is a common hematological disorder. VTE affects millions of people around the world each year and can be fatal. Earlier studies have revealed the possible VTE genetic risk factors in Europeans. The 2018 Critical Assessment of Genome Interpretation (CAGI) challenge had asked participants to distinguish between 66 VTE and 37 non-VTE African American (AA) individuals based on their exome sequencing data. We used variants from AA VTE association studies and VTE genes from DisGeNET database to evaluate VTE risk via four different approaches; two of these methods were most successful at the task. Our best performing method represented each exome as a vector of predicted functional effect scores of variants within the known genes. These exome vectors were then clustered with k-means. This approach achieved 70.8% precision and 69.7% recall in identifying VTE patients. Our second-best ranked method had collapsed the variant effect scores into gene-level function changes, using the same vector clustering approach for patient/control identification. These results show predictability of VTE risk in AA population and highlight the importance of variant-driven gene functional changes in judging disease status. Of course, more in-depth understanding of AA VTE pathogenicity is still needed for more precise predictions.

Systematic review of societal costs associated with stroke, bleeding and monitoring in atrial fibrillation

Aim: Economic consequences associated with the rise in nonvitamin K antagonist oral anticoagulant use on a societal level remain unclear. Materials & methods: Evidence from the past decade on the societal economic burden associated with stroke, bleeding and international normalized ratio monitoring in atrial fibrillation was collected and summarized through a systematic literature review. Results: There were 14 studies identified that reported indirect costs, which were highest among patients with hemorrhagic stroke and intracranial hemorrhage. The contribution of indirect costs to the total was marginal during acute treatment but substantially increased (30-50%) 2 years after stroke and bleeding events. Conclusion: Limited data were available on societal costs in atrial fibrillation and further research is warranted.

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.

Venous Thromboembolism Prophylaxis Strategies for People Undergoing Elective Total Hip Replacement: A Systematic Review and Network Meta-Analysis

OBJECTIVES

To assess the efficacy and safety of venous thromboembolism prophylaxis in people undergoing elective total hip replacement.

METHODS

Systematic review and Bayesian network meta-analyses of randomized controlled trials were conducted for 3 outcomes: deep vein thrombosis (DVT), pulmonary embolism (PE), and major bleeding (MB). MEDLINE, EMBASE, and Cochrane Library (CENTRAL) databases were searched. Study quality was assessed using the Cochrane risk-of-bias checklist. Fixed- and random-effects models were fitted and compared. The median relative risk (RR) and odds ratio (OR) compared with no prophylaxis, with their 95% credible intervals (CrIs), rank, and probability of being the best, were calculated.

RESULTS

Forty-two (n = 24 374, 26 interventions), 30 (n = 28 842, 23 interventions), and 24 (n = 31 792, 15 interventions) randomized controlled trials were included in the DVT, PE, and MB networks, respectively. Rivaroxaban had the highest probability of being the most effective intervention for DVT (RR 0.06 [95% CrI 0.01-0.29]). Strategy of low-molecular-weight heparin followed by aspirin had the highest probability of reducing the risk of PE and MB (RR 0.0011 [95% CrI 0.00-0.096] and OR 0.37 [95% CrI 0.00-26.96], respectively). The ranking of efficacy estimates across the 3 networks, particularly PE and MB, had very wide CrIs, indicating high degree of uncertainty.

CONCLUSIONS

A strategy of low-molecular-weight heparin given for 10 days followed by aspirin for 28 days had the best benefit-risk balance, with the highest probability of being the best on the basis of the results of the PE and MB network meta-analyses. Nevertheless, there is considerable uncertainty around the median ranks of the interventions.

Practical considerations on anticoagulation reversal: spotlight on the reversal of dabigatran

Idarucizumab (Praxbind) is a humanized antibody fragment, that reversibly and with high affinityties up dabigatran (Pradaxa). Anticoagulation reversal is achieved immediately, and with no procoagulant effect. It is administered intravenously and clearance is renal. The main clinical application of idarucizumab is to antagonize bleeding related to dabigatran, especially if it occurs at critical sites, such as nervous system (central or peripheral), intraocular, pericardial, retroperitoneal or pulmonary. Other indications are: i) dabigatran-induced anticoagulation reversal in the need for emergency surgery or procedures at high risk of bleeding; and ii) second-line treatment in bleedings that persist despite local hemostasis procedures. In this narrative review, we comprehensively address clinical indications for idarucizumab, summing up evidence derived from a systematic literature review, but also from case reports.

Clinical and cost-effectiveness of the Ross procedure versus conventional aortic valve replacement in young adults

Objectives

In young and middle-aged adults, there are three current options for aortic valve replacement (AVR), namely mechanical AVR (mechAVR), tissue AVR (biological AVR) and the Ross operation, with no clear guidance on the best option. We aim to compare the clinical effectiveness and cost-effectiveness of the Ross procedure with conventional AVR in young and middle-aged adults.

Methods

This is a systematic literature review and meta-analysis of AVR options. Markov multistate model was adopted to compare cost-effectiveness. Lifetime costs, quality-adjusted life years (QALYs), net monetary benefit (NMB), population expected value of perfect information (EVPI) and expected value of partial perfect information were estimated.

Results

We identified 48 cohorts with a total number of 12 975 patients (mean age 44.5 years, mean follow-up 7.1 years). Mortality, bleeding and thromboembolic events over the follow-up period were lowest after the Ross operation, compared with mechAVR and biological AVR (p<0.001). Aortic reoperation rates were lower after Ross compared with biological AVR, but slightly higher when compared with mechAVR (p<0.001). At a willingness-to-pay threshold of £20effective. At a willingness-to-pay threshold of £20, 000 per QALY000 per QALY, the Ross procedure is more cost-effective compared the Ross procedure is more cost-effective compared withwith conventional AVR, with a lifetime incremental NMB of £60 conventional AVR, with a lifetime incremental NMB of £60 952 (952 (££3030 236236 to to ££7979 464). Incremental costs were £12464). Incremental costs were £12 323 (323 (££61086108 to to ££1515 972) and incremental QALYs 3.66 (1.81972) and incremental QALYs 3.66 (1.81 to to 4.76). The population EVPI indicates that a trial costing up to £2.03 million could be cost 4.76). The population EVPI indicates that a trial costing up to £2.03 million could be cost--effective.

At a willingness-to-pay threshold of £20 000 per QALY, the Ross procedure is more cost-effective compared with conventional AVR, with a lifetime incremental NMB of £60 952 (£30 236 to £79 464). Incremental costs were £12 323 (£6108 to £15 972) and incremental QALYs 3.66 (1.81 to 4.76). The population EVPI indicates that a trial costing up to £2.03 million could be cost-effective.

Conclusions

In young and middle-aged adults with aortic valve disease, the Ross procedure may confer greater quality of life and be more cost-effective than conventional AVR. A high-quality randomised trial could be warranted and cost-effective.

Extended anticoagulation for the secondary prevention of venous thromboembolic events: An updated network meta-analysis

BACKGROUND

Extended treatment is preconized in a significant proportion of patients with unprovoked venous thromboembolism (VTE). However, limited direct/indirect comparisons are available to appropriately weight the benefit/risk ratio of the diverse treatments available. We aimed to compare the rate of symptomatic recurrent VTE and major bleeding (MB), the net clinical benefit (VTE+MB) and death on vitamin-K antagonist (VKA), direct oral anticoagulants (DOAC) and antiplatelet drugs for extended anticoagulation.

METHODS

A systematic literature search through September 2018 identified randomized trials studying these pharmacologic therapies for extended anticoagulation following VTE. Treatment effects were calculated using network meta-analysis with frequentist fixed-effects model.

RESULTS

18 trials (18,221 patients) were included in the analysis. All treatments reduced the risk of recurrence compared to placebo/observation. Nonetheless, VKA (RR 0.22; 95%CI 0.13-0.39) and DOAC (RRs ranging from 0.25-0.32; 95%CI ranging from 0.13-0.52) were more effective than aspirin, whereas low-dose VKA was less effective than standard-dose VKA (RR 2.47; 95%CI 1.34-4.55). The efficacy of DOAC was globally comparable to standard-adjusted dose VKA. Low- (RR 3.13; 95%CI 1.37-7.16) and standard-dose (RR 3.23; 95%CI 1.16-8.99) VKA also increased the risk of MB, which was not the case for any DOAC. Low-dose VKA and low-dose DOAC had similar effects on MB compared to standard-doses. Although there was a trend for reduced MB and enhanced net clinical benefit for DOAC compared to VKA, this was not statistically significant. The specific anticoagulant therapies had no significant effects on deaths.

CONCLUSION

Standard-dose VKA and low/standard-dose DOAC share similar effects on VTE recurrence and MB, whereas aspirin and low-dose VKA were associated with lower benefit/risk ratio.

Risk of hospitalised bleeding in comparisons of oral anticoagulant options for the primary treatment of venous thromboembolism

Understanding of the comparative bleeding risks of oral anticoagulant (OAC) therapies for the primary treatment of venous thromboembolism (VTE) is limited. Therefore, among anticoagulant-naïve VTE patients, we conducted comparisons of apixaban, rivaroxaban and warfarin on the rate of hospitalised bleeding within 180 days of OAC initation. MarketScan databases for the time-period from 2011 to 2016 were used and, for each OAC comparison, new users were matched with up to five initiators of a different OAC. The final analysis included 83 985 VTE patients, who experienced 1944 hospitalised bleeding events. In multivariable-adjusted Cox regression models, rate of hospitalised bleeding was lower among new users of apixaban when compared to new users of rivaroxaban [hazard ratio (95% confidence interval) 0·58 (0·41-0·80)] or warfarin [0·68 (0·50-0·92)]. Overall, the hospitalised bleeding rate was similar when comparing new users of rivaroxaban to new users of warfarin [0·98 (0·68-1·11)], though there was some suggestion that rivaroxaban was associated with lower bleeding risk among younger individuals. Findings from this large real-world population concur with results from the randomised trial which found lower bleeding risk with apixaban versus warfarin and, for the first time, reveal a lower risk of bleeding in a comparison of apixaban versus rivaroxaban.

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

BACKGROUND

Non-vitamin K antagonist oral anticoagulants (NOACs) have been recommended as preferred options for stroke prevention in patients with atrial fibrillation (AF) versus warfarin by guidelines worldwide.

AIM

This study aimed to evaluate the cost-effectiveness of each NOAC in a Thai health care environment, a country with upper middle-income economies based on the World Bank's classification.

METHOD

A lifetime Markov model was created from a Thai societal perspective. The model consisted of 19 health states separated into two cycles: event cycle and consequence cycle. The consequences of AF included in the model were ischaemic stroke, intracranial haemorrhage, extracranial haemorrhage, and myocardial infarction. All NOACs available in Thailand (dabigatran 150 mg and 110 mg twice daily; rivaroxaban 20 mg once daily; apixaban 5 mg twice daily; edoxaban 60 mg and 30 mg once daily) were assessed using warfarin with an international normalised ratio of 2-3 as the reference. Inputs were a combination of published literature and local data when available. A willingness-to-pay of 160,000 Thai baht (THB)/quality-adjusted life year (QALY) was used as the threshold of being cost-effective. Incremental cost-effectiveness ratios and cost-effectiveness acceptability curves were estimated.

RESULTS

All NOACs were not cost-effective strategies for the Thai AF population. The ranking of incremental cost-effectiveness ratios from lowest to highest were apixaban 5 mg twice daily (THB 692,136 or US$21,862) followed by edoxaban 60 mg once daily (THB 911,772 or US$28,799), edoxaban 30 mg once daily (THB 913,749 or US$28,861), dabigatran 150 mg twice daily (THB 1,102,106 or US$34,811), dabigatran 110 mg twice daily (THB 1,195,347 or US$37,756), and rivaroxaban 20 mg once daily (THB 1,347,650 or US$42,566). Cost-effectiveness acceptability curve indicated that apixaban had the highest potential to be a cost-effective strategy versus other NOACs.

CONCLUSIONS

Our findings indicated that all NOACs were not cost-effective in the Thai AF population. Of the NOACs, apixaban may be the most likely to be cost-effective. These data may be useful for policymakers to perform a comprehensive evaluation of these agents for formulary decision and pricing negotiation.

Aspirin use in central retinal arterial occlusion to prevent ischaemic stroke: a retrospective cohort study in Taiwan

OBJECTIVE

To understand the efficacy of aspirin use for preventing ischaemic stroke after central retinal artery occlusion (CRAO).

DESIGN

The retrospective cohort study was conducted using the National Health Insurance Research Database from 1998 to 2013.

SETTING

A population-based study.

PARTICIPANTS

A total of 9437 participants with newly diagnosed CRAO were identified. Participants who had a previous stroke and/or retinal vascular occlusion, were aged <20 years and used aspirin 3 months before the event were excluded. There were 3778 eligible participants matched by propensity score, and they were divided into aspirin (n=434) and aspirin-naive (n=1736) groups after the matching.

METHODS

Cox proportional hazard models and cumulative survival curves were used to assess ischaemic stroke in the study groups, along with log-rank tests to compare group differences.

MAIN OUTCOME MEASURES

Incidence of ischaemic stroke in the aspirin and aspirin-naive groups 1 year after CRAO.

RESULTS

Of the 3778 patients with newly diagnosed CRAO, 151 (4%) had a subsequent ischaemic stroke within 1 year. The risk was especially high during the first week of the CRAO. No difference between the aspirin and aspirin-naive groups was found in risk of ischaemic stroke, haemorrhagic stroke, gastrointestinal bleeding, major bleeding, acute coronary syndrome, retinal vein occlusion, new-onset glaucoma, undergoing panretinal photocoagulation or all-cause mortality. Risk factors for ischaemic stroke within 1 year of CRAO included male gender (p=0.031; HR=1.46) and age (p=0.032; HR=1.14).

CONCLUSIONS

Aspirin use after a CRAO showed no benefit on attenuating the risk of ischaemic stroke. The risk of ischaemic stroke was increased after CRAO especially during the first week. Male gender and age were risk factors for ischaemic stroke after CRAO.

Cost-effectiveness analysis of case management for optimized antithrombotic treatment in German general practices compared to usual care - results from the PICANT trial

BACKGROUND

By performing case management, general practitioners and health care assistants can provide additional benefits to their chronically ill patients. However, the economic effects of such case management interventions often remain unclear although how to manage the burden of chronic disease is a key question for policy-makers. This analysis aimed to compare the cost-effectiveness of 24 months of primary care case management for patients with a long-term indication for oral anticoagulation therapy with usual care.

METHODS

This analysis is part of the cluster-randomized controlled Primary Care Management for Optimized Antithrombotic Treatment (PICANT) trial. A sample of 680 patients with German statutory health insurance was initially considered for the cost analysis (92% of all participants at baseline). Costs included all disease-related direct health care costs from the payer's perspective (German statutory health insurers) plus case management costs for the intervention group. A-Quality Adjusted Life Year (QALY) measurement (EQ-5D-3 L instrument) was used to evaluate utility, and incremental cost-effectiveness ratio (ICER) to assess cost-effectiveness. Mean differences were calculated and displayed with 95%-confidence intervals (CI) from non-parametric bootstrapping (1000 replicates).

RESULTS

N = 505 patients (505/680, 74%) were included in the cost analysis (complete case analysis with a follow-up after 12 and 24 months as well as information on cost and QALY). After two years, the mean difference of direct health care costs per patient (€115, 95% CI [- 201; 406]) and QALYs (0.03, 95% CI [- 0.04; 0.11]) in the two groups was small and not significant. The costs of case management in the intervention group caused mean total costs per patient in this group to rise significantly (mean difference €503, 95% CI [188; 794]). The ICER was €16,767 per QALY. Regardless of the willingness of insurers to pay per QALY, the probability of the intervention being cost-effective never rose above 70%.

CONCLUSIONS

A primary care case management for patients with a long-term indication for oral anticoagulation therapy improved QALYs compared to usual care, but was more costly. However, the results may help professionals and policy-makers allocate scarce health care resources in such a way that the overall quality of care is improved at moderate costs, particularly for chronically ill patients.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN41847489 .

Hospitalization period and direct medical cost in patients using warfarin or novel oral anti-coagulants after a cerebral embolism

Background Warfarin has been used in Japan for a long time in patients after cerebral embolism to prevent recurrence. Recently, several novel oral anti-coagulants (NOACs) have been approved for use and are gradually replacing warfarin. However, it remains unclear whether warfarin and other NOACs differ from each other with respect to drug costs and length of stay (LOS) during treatment in Japan. Objective To assess differences in LOS and direct medical cost between patients after cerebral embolism treated with warfarin and those treated with NOACs. Setting Thirteen acute care hospitals in Japan. Method For hospitalized patients with cerebral embolisms who were treated with NOACs and/or warfarin between April 2012 and March 2014, we assessed LOS for patients with warfarin and NOAC using log-rank test, and stratified proportional hazard regression. Also, we assess direct medical cost using paired-t test. Main Outcome measure LOS and medical cost after first treatment with warfarin and NOAC. Results The median LOS for NOACs-treated patients was 12.5 days and that for warfarin treated patients was 19.0 days while the corresponding mean medical costs were USD 7151 ± 6228 [JPY 736,546 ± 641,437] and USD 8950 ± 5891 [JPY 921,830 ± 606,765]. The drug cost for NOACs-treated patients was higher but costs for laboratory-test and hospitalization were lower than those for warfarin-treated patients. Conclusions For NOAC-treated patients, LOS was shorter, and medical cost during hospitalization tended to be lower than those for warfarin-treated patients, whereas NOACs prices were higher than warfarin price.

A prospective multicenter observational study evaluating the risk of periendoscopic events in patients using anticoagulants: the Osaka GIANT Study

Background and study aims  An increasing number of patients have been using anticoagulants including anti-vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs); however, in patients using anticoagulants, limited data are available with regard to the risks of gastrointestinal bleeding and thromboembolic events during the peri-endoscopic period. We aimed to evaluate the peri-endoscopic bleeding and thrombotic risks in patients administered VKAs or DOACs. Patients and methods  Consecutive patients using anticoagulants who underwent endoscopic biopsy, mucosal resection, or submucosal dissection were prospectively enrolled across 11 hospitals. The primary outcome assessed was difference in incidence of post-procedural gastrointestinal bleeding in patients using VKAs and DOACs. Duration of hospitalization and peri-procedural thromboembolic events were also compared. Results  We enrolled 174 patients using VKAs and 37 using DOACs. In total, 16 patients using VKA were excluded from the analysis because of cancellation of endoscopic procedures and contraindications to the use of DOACs; 128 (81 %) patients using VKAs and 17 (46 %) using DOACs received heparin-bridging therapy (HB). The rate of post-procedural gastrointestinal bleeding in DOAC users was similar to that in VKA users (16.2 % vs. 16.4 %, P  = 1.000). Duration of hospitalization was significantly longer in patients using VKAs than in those using DOACs (median 15 vs. 7 days, P  < 0.0001). Myocardial infarction occurred during pre-endoscopic HB in one patient using VKAs. Conclusion  DOAC administration showed similar post-procedural gastrointestinal bleeding risk to VKA administration in patients undergoing endoscopic procedures, but it shortened the hospital stay.

Non–Vitamin K Antagonist Oral Anticoagulants in the Treatment of Atrial Fibrillation

Atrial fibrillation (AF) increases a patient's stroke risk four- to five-fold. Anticoagulation with the vitamin K antagonist (VKA) warfarin reduces the risk of stroke by 67%, but warfarin carries a significant risk of major bleeding and has unpredictable pharmacodynamics with a narrow therapeutic window, necessitating frequent monitoring of its anticoagulant effect. The non–vitamin K antagonist oral anticoagulants (NOACs) dabigatran, rivaroxaban, apixaban, and edoxaban provide more predictable anticoagulant activity than warfarin with a lower risk of major bleeding, and each is noninferior to warfarin for the prevention of stroke. All have earned regulatory approval in the past eight years. At least one of the NOACs is approved for use in all patients with AF, except those with mechanical valves and rheumatic mitral valve disease, for whom warfarin remains the only option. Recent clinical trials have shown that antithrombotic regimens including NOACs are safe and effective in patients with AF who need potent antiplatelet therapy.

Increased serum exosomal miR-134 expression in the acute ischemic stroke patients

BACKGROUND

The exosomal miRNAs have been emerged as biomarkers and therapeutic targets for various diseases, however, the function of exosomal miRNAs in stroke remains largely unknown.

METHODS

The blood samples from acute ischemic stroke (AIS) patients and normal controls were collected. The exosomes were isolated from the blood samples, which were confirmed by electron microscopy and western blot with the specific exosomes biomarker CD9, CD63 and Tsg101.

RESULTS

RT-qPCR analysis showed that exosomal miR-134 was significantly increased in AIS patients within 24 h after stroke onset compared with that of control group. Highly expressed exosomal miR-134 was correlated with the National Institutes of Health Stroke Scale (NIHSS) scores, infarct volume and positively associated with the worse prognosis of the stroke patients. Additionally, the exosomal miR-134 was strong positively correlated with the expression of serum interleukin 6 (IL-6) and plasma high-sensitivity C relative protein (hs-CRP). The receiver operating characteristic (ROC) curve suggested that miR-134 might be a potential factor to discriminate AIS patients from non-stroke controls.

CONCLUSIONS

The exosomal miR-134 as a possible novel biomarker for the diagnosis and prognosis of stroke.

Laboratory Assessment of the Anticoagulant Activity of Apixaban in Patients With Nonvalvular Atrial Fibrillation

Our aim is to determine the most appropriate laboratory tests, besides anti-factor Xa (anti-FXa) chromogenic assays, to estimate the degree of anticoagulation with apixaban and compare it with that of rivaroxaban in real-world patients. Twenty patients with nonvalvular atrial fibrillation treated with apixaban 5 mg twice daily and 20 patients on rivaroxaban 20 mg once daily were studied. Conventional coagulation tests, thrombin generation assay (TGA), and thromboelastometry (nonactivated TEM [NATEM] assay) were performed in the 40 patients and 20 controls. The anti-FXa chromogenic assays were used to measure apixaban and rivaroxaban plasma levels. The NATEM measurements showed no significant difference between the 2 groups of patients. Concerning TGA, endogenous thrombin potential (ETP) was significantly decreased in patients on rivaroxaban as compared to those treated with apixaban (P < .003). A statistically significant, strong inverse correlation between apixaban plasma concentrations and ETP (P < .001) was observed. Apixaban significantly reduces ETP compared to controls, but to a lesser extent than rivaroxaban. Thrombin generation assay might provide additional information on apixaban exposure, which is required in order to individualize treatment especially for patients with a high bleeding risk. Our findings have to be further investigated in studies with larger sample sizes, in the entire range of apixaban exposure, with other direct oral anticoagulants, and in relation to clinical outcomes.

Cost-Utility Analysis of Venous Thromboembolism Prophylaxis Strategies for People Undergoing Elective Total Hip and Total Knee Replacement Surgeries in the English National Health Service

Background: Major orthopedic surgery, such as elective total hip replacement (eTHR) and elective total knee replacement (eTKR), are associated with a higher risk of venous thromboembolism (VTE) than other surgical procedures. Little is known, however, about the cost-effectiveness of VTE prophylaxis strategies in people undergoing these procedures. Aim: The aim of this work was to assess the cost-effectiveness of these strategies from the English National Health Service perspective to inform NICE guideline (NG89) recommendations. Materials and Methods: Cost-utility analysis, using decision modeling, was undertaken to compare 15 VTE prophylaxis strategies for eTHR and 12 for eTKR, in addition to "no prophylaxis" strategy. The analysis complied with the NICE Reference Case. Structure and assumptions were agreed with the guideline committee. Incremental net monetary benefit (INMB) was calculated, vs. the model comparator (LMWH+ antiembolism stockings), at a threshold of £20,000/quality-adjusted life-year (QALY) gained. The model was run probabilistically. Deterministic sensitivity analyses (SAs) were undertaken to assess the robustness of the results. Results: The most cost-effective strategies were LMWH for 10 days followed by aspirin for 28 days (INMB = £530 [95% CI: -£784 to £1,103], probability of being most cost-effective = 72%) for eTHR, and foot pump (INMB = £353 [95% CI: -£101 to £665]; probability of being most cost-effective = 18%) for eTKR. There was considerable uncertainty regarding the cost-effectiveness ranking in the eTKR analysis. The results were robust to change in all SAs. Conclusions: For eTHR, LMWH (standard dose) for 10 days followed by aspirin for 28 days is the most cost-effective VTE prophylaxis strategy. For eTKR, the results are highly uncertain but foot pump appeared to be the most cost-effective strategy, followed closely by aspirin (low dose). Future research should focus on assessing cost-effectiveness of VTE prophylaxis in the eTKR population.

Vitamin K Antagonists, Non-Vitamin K Antagonist Oral Anticoagulants, and Vascular Calcification in Patients with Atrial Fibrillation

Background  Vitamin K antagonists (VKAs) are associated with coronary artery calcification in low-risk populations, but their effect on calcification of large arteries remains uncertain. The effect of non-vitamin K antagonist oral anticoagulants (NOACs) on vascular calcification is unknown. We investigated the influence of use of VKA and NOAC on calcification of the aorta and aortic valve. Methods  In patients with atrial fibrillation without a history of major adverse cardiac or cerebrovascular events who underwent computed tomographic angiography, the presence of ascending aorta calcification (AsAC), descending aorta calcification (DAC), and aortic valve calcification (AVC) was determined. Confounders for VKA/NOAC treatment were identified and propensity score adjusted logistic regression explored the association between treatment and calcification (Agatston score > 0). AsAC, DAC, and AVC differences were assessed in propensity score-matched groups. Results  Of 236 patients (33% female, age: 58 ± 9 years), 71 (30%) used VKA (median duration: 122 weeks) and 79 (34%) used NOAC (median duration: 16 weeks). Propensity score-adjusted logistic regression revealed that use of VKA was significantly associated with AsAC (odds ratio [OR]: 2.31; 95% confidence interval [CI]: 1.16-4.59; p  = 0.017) and DAC (OR: 2.38; 95% CI: 1.22-4.67; p  = 0.012) and a trend in AVC (OR: 1.92; 95% CI: 0.98-3.80; p  = 0.059) compared with non-anticoagulation. This association was absent in NOAC versus non-anticoagulant (AsAC OR: 0.51; 95% CI: 0.21-1.21; p  = 0.127; DAC OR: 0.80; 95% CI: 0.36-1.76; p  = 0.577; AVC OR: 0.62; 95% CI: 0.27-1.40; p  = 0.248). A total of 178 patients were propensity score matched in three pairwise comparisons. Again, use of VKA was associated with DAC ( p  = 0.043) and a trend toward more AsAC ( p  = 0.059), while use of NOAC was not (AsAC p  = 0.264; DAC p  = 0.154; AVC p  = 0.280). Conclusion  This cross-sectional study shows that use of VKA seems to contribute to vascular calcification. The calcification effect was not observed in NOAC users.

The risk of delayed intracranial hemorrhage with direct acting oral anticoagulants after trauma: A two-center study

BACKGROUND

The aim of this study was to characterize the risk of a delayed intracranial hemorrhage (ICH) in trauma patients on direct-acting oral anticoagulants (DOACs).

METHODS

Patients on DOACs admitted to two Level I Trauma Centers between 2014 and 2017 were reviewed. Only patients with a negative admission CT brain were included. The primary outcome was a delayed ICH.

RESULTS

Overall, 249 patients were included. The median age was 81 years with 82% undergoing a repeat CT. Three patients developed a delayed ICH (1.2%). One developed an ICH after receiving tissue plasminogen activator for a cerebrovascular accident after two negative CTs. Excluding this patient, the incidence dropped to 0.8%. None required neurosurgical intervention.

CONCLUSION

For patients at risk for a TBI who are on DOACs, repeat cross-sectional imaging of the brain when the initial imaging is negative is not necessary. A period of clinical observation may be warranted.

Risks and benefits of direct oral anticoagulants versus warfarin in a real world setting: cohort study in primary care

OBJECTIVE

To investigate the associations between direct oral anticoagulants (DOACs) and risks of bleeding, ischaemic stroke, venous thromboembolism, and all cause mortality compared with warfarin.

DESIGN

Prospective open cohort study.

SETTING

UK general practices contributing to QResearch or Clinical Practice Research Datalink.

PARTICIPANTS

132 231 warfarin, 7744 dabigatran, 37 863 rivaroxaban, and 18 223 apixaban users without anticoagulant prescriptions for 12 months before study entry, subgrouped into 103 270 patients with atrial fibrillation and 92 791 without atrial fibrillation between 2011 and 2016.

MAIN OUTCOME MEASURES

Major bleeding leading to hospital admission or death. Specific sites of bleeding and all cause mortality were also studied.

RESULTS

In patients with atrial fibrillation, compared with warfarin, apixaban was associated with a decreased risk of major bleeding (adjusted hazard ratio 0.66, 95% confidence interval 0.54 to 0.79) and intracranial bleeding (0.40, 0.25 to 0.64); dabigatran was associated with a decreased risk of intracranial bleeding (0.45, 0.26 to 0.77). An increased risk of all cause mortality was observed in patients taking rivaroxaban (1.19, 1.09 to 1.29) or on lower doses of apixaban (1.27, 1.12 to 1.45). In patients without atrial fibrillation, compared with warfarin, apixaban was associated with a decreased risk of major bleeding (0.60, 0.46 to 0.79), any gastrointestinal bleeding (0.55, 0.37 to 0.83), and upper gastrointestinal bleeding (0.55, 0.36 to 0.83); rivaroxaban was associated with a decreased risk of intracranial bleeding (0.54, 0.35 to 0.82). Increased risk of all cause mortality was observed in patients taking rivaroxaban (1.51, 1.38 to 1.66) and those on lower doses of apixaban (1.34, 1.13 to 1.58).

CONCLUSIONS

Overall, apixaban was found to be the safest drug, with reduced risks of major, intracranial, and gastrointestinal bleeding compared with warfarin. Rivaroxaban and low dose apixaban were, however, associated with increased risks of all cause mortality compared with warfarin.

Cost-effectiveness of rivaroxaban and aspirin compared to aspirin alone in patients with stable cardiovascular disease: An Australian perspective

OBJECTIVE

In light of the Cardiovascular Outcomes for People using Anticoagulation Strategies (COMPASS) trial, our objective was to assess the cost-effectiveness, from the Australian healthcare perspective, of rivaroxaban in combination with aspirin versus aspirin alone for the prevention of recurrent cardiovascular disease among patients with stable atherosclerotic vascular disease.

METHODS

A Markov model was developed using input data from the COMPASS trial to predict the clinical course and costs of patients over a 20-year time-horizon. The model comprised of three health states: 'Alive without recurrent CVD', 'Alive after recurrent CVD' and 'Dead'. Costs were from the Australian public healthcare system perspective, and estimated from published sources, as were utility data. The costs of rivaroxaban were based on current acquisition prices on the Australian Pharmaceutical Benefits Schedule (PBS) and assumed as AUD$3.09/day. The main outcome of interest was the incremental cost-effectiveness ratio (ICER) in terms of cost per quality adjusted life year (QALY) gained, and cost per year of life saved (YoLS). Costs and benefits were discounted by 5.0% per year.

RESULTS

Compared to aspirin alone, rivaroxaban plus aspirin was estimated to cost an additional AUD$12,156 (discounted) per person, but lead to 0.516 YoLS (discounted) and 0.386 QALYs gained (discounted), over 20 years. These equated to ICERs of AUD$23,560/YoLS and AUD$31,436/QALY gained. We have assumed a threshold of AUD$50,000/QALY gained to signify cost-effectiveness.

CONCLUSION

Compared to aspirin, rivaroxaban in combination with aspirin is likely to be cost-effective in preventing recurrent cardiovascular events in patients with stable atherosclerotic vascular disease.

Medicare part D prescribing for direct oral anticoagulants in the United States: Cost, use and the "rubber effect"

INTRODUCTION

Direct oral anticoagulants (DOAC) have gained an increased share over warfarin for prevention and treatment of thromboembolic disease. We studied DOAC adoption across providers and medical specialties.

METHODS

Retrospective, cross-sectional analysis of Medicare Part D public use files (PUF), 2013 to 2015. We summarized prescription data for claims and drug payment, stratified by drug class, specialty and calendar year. We treated DOAC claims as a count outcome and explored patterns of expansion across prescribers via a truncated negative binomial regression. We described dispersion and spread in DOAC prescribing, across hospital referral regions (HRRs), including the p90/p10 ratios, and the median absolute deviation from the median.

RESULTS

In 2015 part D PUF, oral anticoagulant claims have climbed to approximately 24.4 million with a payment cost of approximately $3.3 billion. DOAC claims comprised 31.0% of oral anticoagulant claims, showing a relative increase of approximately 127% compared to 2013. The upper decile of prescribers accounted for half of the oral anticoagulant prescriptions and the resulting cost. The median cost per DOAC claim in 2015 was $367.4 (interquartile range 323.9 to 445.9), as opposed to $12.3 (interquartile range 9.2 to 16.5) for warfarin. The median cost per standardized (30-day supply) prescription was $317.0 (interquartile range 303.8 to 324.3) and $8.0 (6.7 to 9.8) for DOACs and warfarin, respectively. DOAC adoption differs by specialty. Cardiologists, cardiac electrophysiologists and orthopedics had the highest predicted DOAC share per 100 claims (53.8, 72.9 and 71.5, respectively in 2015); nephrologists, family practitioners and geriatricians the lowest (22.3, 21.5 and 20.7, respectively in 2015). The p90/p10 ratio and the median absolute deviation from the median varied across HRRs and correlated positively with the prevalence of stroke and atrial fibrillation in the Medicare population.

CONCLUSIONS

DOACs have been increasing their share year-over-year, but adoption varies across specialties. In prevalent areas for stroke and atrial fibrillation, prescription dispersion magnifies, and this may signify a rapid adoption by top providers.

Efficacy and safety of direct oral anticoagulants approved for cardiovascular indications: Systematic review and meta-analysis

BACKGROUND

Direct oral anticoagulants (DOACs) have emerged as promising alternatives to vitamin K antagonists (VKAs) for patients with non-valvular atrial fibrillation (NVAF) or venous thromboembolism (VTE). Few meta-analyses have included all DOACs that have received FDA approval for these cardiovascular indications, and their overall comparisons against VKAs have shortcomings in data and methods. We provide an updated overall assessment of the efficacy and safety of those DOACs at dosages currently approved for NVAF or VTE, in comparison with VKAs.

METHODS

We used data from Phase 3 randomized trials that compared an FDA-approved DOAC with VKA for primary prevention of stroke in patients with NVAF or for treatment of acute VTE.

RESULTS

Among trial participants with NVAF, DOAC recipients had a lower risk of stroke or systemic embolism [Pooled Odds Ratio (OR) 0.76, 95% Confidence Interval (CI) (0.68-0.84)], any stroke (0.80, 0.73-0.88), systemic embolism (0.56, 0.34-0.93), and total mortality (0.89, 0.84-0.95). Safety outcomes also showed a lower risk of fatal, major, and intracranial bleeding but higher risk for gastrointestinal bleeding (GIB). Patients with acute VTE randomized to DOACs had comparable risk of recurrent VTE and death (OR 0.88, 95% CI 0.75-1.03), recurrent DVT (0.83, 0.66-1.05), recurrent non-fatal PE (0.97, 0.75-1.25), and total mortality (0.94, 0.79-1.12). Safety outcomes for DOACs showed a lower risk of major, fatal, and intracranial bleeding, but similar risk of GIB.

CONCLUSIONS

Patients receiving DOACs for NVAF had predominantly superior efficacy and safety. Patients who were treated with DOACs for acute VTE had non-inferior efficacy, but an overall superior safety profile.

Opportunistic pulse checks in primary care to improve recognition of atrial fibrillation: a retrospective analysis of electronic patient records

BACKGROUND

Atrial fibrillation (AF) is an important and modifiable risk factor for stroke. Earlier identification may reduce stroke-related morbidity and mortality. Trial evidence shows that opportunistic pulse regularity checks in individuals aged ≥65 years increases detection of AF. However, this is not currently recommended by the National Screening Programme or implemented by most clinical commissioning groups (CCGs).

AIM

To evaluate the impact of a systematic programme to promote pulse regularity checks, the programme's uptake in general practice, and the prevalence of AF.

DESIGN AND SETTING

Retrospective analysis of electronic primary care patient records in three east London CCGs (City and Hackney, Newham, and Tower Hamlets) over 10 years.

METHOD

Rates of pulse regularity checks and prevalence of AF in individuals aged ≥65 years were compared from the pre-intervention period, 2007-2011, to the post-intervention period, 2012-2017.

RESULTS

Across the three CCGs, rates of pulse regularity checks increased from a mean of 7.3% pre-intervention to 66.4% post-intervention, achieving 93.1% (n = 58 722) in the final year. Age-standardised prevalence of AF in individuals aged ≥65 years increased significantly from a pre-intervention mean of 61.4/1000 to a post-intervention mean of 64.5/1000. There was a significant increase in a post-intervention trend to a final-year mean of 67.3/1000: an improvement of 9.6% (5.9/1000) with 790 additional new cases identified.

CONCLUSION

Organisational alignment, standardised data entry, peer-performance dashboards, and financial incentives rapidly and generally increased opportunistic screening with pulse regularity checks. This was associated with a significant increase in detection and prevalence of AF and is of public health importance.

Monotherapy of acetylsalicylic acid or warfarin for prevention of ischemic stroke in low-risk atrial fibrillation: A Easter Asian population-based study

BACKGROUND

This study aimed to investigate the effectiveness of monotherapy acetylsalicylic acid (ASA) and warfarin for stroke prevention in low-risk atrial fibrillation (AF) by using a population- -based cohort study in Taiwan.

METHODS

A newly diagnosed low-risk AF patient cohort were identified by using National Health Insurance Research Database (NHIRD) in Taiwan in 2008. The study cohort was observed with a follow-up of 2 years to examine the onset of ischemic stroke (IS) (to 2010). The longitudinal data were analyzed by using generalized estimation equations (GEE).

RESULTS

A total of 8,065 newly-diagnosed low-risk AF patients were identified in 2008. 7.4% were prescribed with ASA and 4.6% were prescribed with warfarin. The GEE results showed that low-risk AF patients with hypertension who received warfarin were associated with a statistically significant 58.4% reduction of IS risk (OR = 0.416, p = 0.024, 95% CI 0.194-0.891). Additionally, low-risk AF patients with hyperlipidemia who received warfarin were associated with a 69.3% reduction of IS risk (OR = 0.307, p = 0.044, 95% CI 0.097-0.969).

CONCLUSIONS

Warfarin is suggested to be prescribed in preventing IS for low-stroke-risk AF patients with hypertension and hyperlipidemia.

Time trends in antithrombotic management of patients with atrial fibrillation treated with coronary stents: Results from TALENT-AF (The internAtionaL stENT - Atrial Fibrillation study) multicenter registry

BACKGROUND

Antithrombotic management of patients with atrial fibrillation (AF) requiring percutaneous coronary intervention (PCI) is highly variable; limited evidence-based guidelines exist to influence practice.

HYPOTHESIS

Patient characteristics and availability of novel drugs may have contributed to practice variability.

METHODS

We undertook an international multicenter retrospective registry of AF patients treated with PCI. The primary measures of interest were antiplatelet and OAC prescriptions at discharge. We compared temporal trends between Prior (2010-2012) and Recent (2013-2015) cohorts and investigated variables associated with OAC prescription.

RESULTS

We identified 488 cases (140 Prior, 348 Recent). Median CHADS₂ and HAS-BLED scores were 2 (IQR, 1-3) and 2 (IQR, 2-3). Clinical characteristics were similar between cohorts, with high (85%) prevalence of ACS. More patients in the Recent cohort, compared with Prior, received OAC (56.9% vs 44.3%; P = 0.01) and NOAC (27.3% vs 3.6%; P < 0.01) at baseline. Triple therapy at discharge was not different between the cohorts. Clinical presentation with ACS and consequent use of potent P2Y₁₂ inhibitors were associated with reduced odds of OAC prescription at discharge (OR: 0.57, P = 0.045 and OR: 0.38, P = 0.023, respectively).

CONCLUSIONS

Despite little change over time in clinical characteristics of AF patients undergoing PCI, significantly more patients received OAC at presentation. However, triple therapy was not more frequent in the Recent cohort, and ACS presentation was associated with lack of OAC at discharge. We underscore the need for trial evidence and use of updated guidelines to assist clinicians in balancing ischemic and bleeding risks.

Comparison of major bleeding risk in patients with non-valvular atrial fibrillation receiving direct oral anticoagulants in the real-world setting: a network meta-analysis

OBJECTIVE

To conduct a systematic literature review (SLR) and network meta-analysis (NMA) of real-world studies comparing major bleeding risk among patients with non-valvular atrial fibrillation (NVAF) on direct oral anticoagulants (DOACs) or warfarin.

METHODS

Systematic searches were conducted in MEDLINE and Embase for full-text articles published between January 1, 2003 and March 18, 2017. Eligible studies compared at least two of the following in a real-world setting: warfarin, apixaban, dabigatran, rivaroxaban, or edoxaban. A Bayesian NMA was conducted to estimate hazard ratios (HRs) for major bleeding using a random-effects model.

RESULTS

Eleven studies were included in the NMA. Nine studies included DOACs vs Warfarin comparisons, and four studies included DOACs vs DOACs comparisons (two studies included both comparisons). Median follow-up duration ranged from 2.6-31.2 months. No evidence was identified for edoxaban. Apixaban was associated with a significantly lower risk of major bleeding compared to other oral anticoagulants (warfarin HR = 0.58; 95% credible interval [CrI] = 0.48-0.69; dabigatran = 0.73; 0.61-0.87; rivaroxaban = 0.55; 0.46-0.66). Dabigatran was associated with a significantly lower risk than warfarin (0.79; 0.71-0.88) and rivaroxaban (0.76; 0.67-0.85), and rivaroxaban was not statistically different from warfarin (1.05; 0.91-1.19). Sensitivity analyses with standard dose and sponsorship showed consistent results.

CONCLUSION

DOACs were associated with lower or similar risk of major bleeding compared with warfarin in NVAF patients. Apixaban was associated with a significantly lower risk of major bleeding than other DOACs. Dabigatran was associated with a significantly lower risk of major bleeding compared to rivaroxaban and warfarin.