Clinical and Safety Outcomes of Oral Antithrombotics for Stroke Prevention in Atrial Fibrillation: A Systematic Review and Network Meta-analysis

Real-World Risk of Gastrointestinal Bleeding for Direct Oral Anticoagulants and Warfarin Users: A Distributed Network Analysis Using a Common Data Model

Background/Aims

Early studies on direct oral anticoagulants (DOACs) reported a higher risk of gastrointestinal bleeding (GIB) compared with warfarin; however, recent studies have reported a reduced risk. Therefore, this study was designed to evaluate the risk of GIB in users of DOAC and warfarin.

Methods

Using a common data model, we investigated the comparative risk of GIB in subjects from eight hospitals who were newly prescribed DOACs or warfarin. We excluded subjects who had a prior history of GIB or had been prescribed both medications. After propensity score matching, we analyzed 3,347 matched pairs of new DOAC and new warfarin users.

Results

The risk of GIB in new DOAC users was comparable to that in new warfarin users (hazard ratio [HR], 0.95; 95% confidence interval [CI], 0.65 to 1.40; p=0.808). New DOAC users had a similar risk of GIB to new warfarin users among older patients >65 years (HR, 1.00; 95% CI, 0.69 to 1.52; p=0.997) and in older patients >75 years (HR, 1.21; 95% CI, 0.68 to 2.10; p=0.509). In addition, the risk of GIB was not significantly different between two groups according to sex. We also found that the risk of GIB in DOAC users was 26% lower in edoxaban or apixaban subgroups compared to rivaroxaban or dabigatran subgroups (HR, 0.74; 95% CI, 0.69 to 1.00; p=0.049).

Conclusions

In real-world practice, the risk of GIB in new DOAC users is comparable to that in new warfarin users. In DOAC users, the risk of GIB was lower in edoxaban or apixaban subgroups than rivaroxaban or dabigatran subgroups.

Effectiveness and safety of direct oral anticoagulation vs. warfarin in frail patients with atrial fibrillation

AIMS

Although frail patients with atrial fibrillation (AF) carry a high risk of stroke and treatment-related bleeding complications, evidence for the safety and effectiveness of anticoagulation remains sparse. This study investigated the effectiveness and safety of direct oral anticoagulant (DOAC) vs. warfarin in frail AF patients.

METHODS AND RESULTS

Nationwide registry-based cohort study including 32 048 anticoagulation naïve frail patients (median age 80 years, 53% female) with incident AF during 2012-20. Frailty was assessed using the hospital frailty risk score. To address baseline confounding, we applied inverse probability of treatment weighting (IPTW) and marginal structural models with weighted pooled regression to compute weighted hazard ratios (wHRs) and risk differences for thromboembolism and major bleeding comparing specific DOAC doses with warfarin. After AF diagnosis, 6747 (21.1%) initiated warfarin, 17 076 (50.3%) initiated standard-dose DOAC, and 9179 (28.6%) initiated reduced-dose DOAC. Comparative effectiveness analyses in the IPTW pseudo-populations revealed similar thromboembolism risk between standard-dose DOAC and warfarin [wHR 0.95, 95% confidence interval (CI) 0.80-1.13] and between reduced-dose DOAC and warfarin (wHR 0.97, 95% CI 0.77-1.23). The 1-year thromboembolic event-free survival difference was -0.2% for DOAC, regardless of dosing, vs. warfarin. Major bleeding risk was significantly lower with standard-dose DOAC (wHR 0.69, 95% CI 0.59-0.87) and reduced-dose DOAC (wHR 0.67, 95% CI 0.55-0.81) vs. warfarin. The 1-year bleeding risk difference with DOAC ranged from -1.3% to -3.0%.

CONCLUSION

Our findings indicate comparable thromboembolism risk and significantly lower bleeding risk with both standard and reduced DOAC regimens compared with warfarin in frail AF patients in routine care.

Managing older people with atrial fibrillation and preventing stroke: a review of anticoagulation approaches

INTRODUCTION

Oral anticoagulants (OACs) are the cornerstone of stroke prevention in atrial fibrillation (AF), but prescribing decisions in older people are complicated. Clinicians must assess the net clinical benefit of OAC in the context of multiple chronic conditions, polypharmacy, frailty and life expectancy. The under-representation of high-risk, older adult sub-populations in clinical trials presents the challenge of choosing the right OAC, where a 'one-size-fits-all' approach cannot be taken.

AREAS COVERED

This review discusses OAC approaches for stroke prevention in older people with AF and presents a prescribing aid to support clinicians' decision-making. High-risk older adults with multiple chronic conditions, specifically chronic kidney disease, dementia/cognitive impairment, previous stroke/transient ischemic attack or intracranial hemorrhage, polypharmacy, frailty, low body weight, high falls risk, and those aged ≥75 years are considered.

EXPERT OPINION

Non-vitamin K antagonist OACs are the preferred first-line OAC in older adults with AF, including high-risk subpopulations, after individual assessment of stroke and bleeding risk, except those with mechanical heart valves and moderate-to-severe mitral stenosis. Head-to-head comparisons of NOACs are not available, therefore the choice of drug (and dose) should be based on an individual's risk (stroke and bleeding) and incorporate their treatment preferences. Treatment decisions must be person-centered and principles of shared decision-making applied.

Efficacy and Safety of Oral Anticoagulants in Older Adult Patients With Atrial Fibrillation: Pairwise and Network Meta-Analyses

OBJECTIVE

To evaluate the efficacy and safety of oral anticoagulants for older adult patients with atrial fibrillation (AF).

DESIGN

Pairwise and network meta-analyses.

SETTING AND PARTICIPANTS

Patients with AF aged ≥75 years.

METHODS

PubMed, Embase, and the Cochrane library were searched for published randomized controlled trials and adjusted observational studies evaluating the use of a non-vitamin K antagonist oral anticoagulants (NOACs), vitamin K antagonist, or antiplatelet drug for the prevention of stroke. The primary efficacy and safety outcomes were the composite of stroke and systemic embolism (SSE) and major bleedings.

RESULTS

This study included 38 studies enrolling 1,022,908 older adult patients with AF. Results from pairwise meta-analyses showed that NOACs were superior to warfarin for all outcomes, except that dabigatran increased the risk of gastrointestinal (GI) bleedings. Aspirin was associated with a higher risk of SSE and ischemic stroke than warfarin or NOACs. Results of network meta-analyses indicated that apixaban significantly reduced the risk of SSE, major bleedings, and GI bleedings than warfarin, rivaroxaban, and dabigatran. Apixaban, edoxaban, rivaroxaban, and dabigatran reduced the risk of ischemic stroke and intracranial bleeding compared to warfarin. Dabigatran showed lower risk of all-cause mortality than warfarin and of intracranial bleeding than rivaroxaban.

CONCLUSIONS AND IMPLICATIONS

NOACs are of at least equal efficacy, or even superior to warfarin. The safety profile of individual NOAC agents was significantly different, as apixaban performs better than the other oral anticoagulants in reducing major bleeding and GI bleeding, whereas dabigatran increased the risk of GI bleeding.

Severe Bleeding Risk of Direct Oral Anticoagulants Versus Vitamin K Antagonists for Stroke Prevention and Treatment in Patients with Atrial Fibrillation: A Systematic Review and Network Meta-Analysis

PURPOSE

We aimed to determine the safety of direct oral anticoagulants (DOACs) for stroke prevention and treatment in patients with atrial fibrillation (AF).

METHODS

A systematic search of four databases (PubMed, EMBASE, Web of Science, and Cochrane Library) was performed to identify randomized controlled trials (RCTs) reporting severe bleeding events in patients taking DOACs or vitamin K antagonists (VKAs). In this frequency-based network meta-analysis, odds ratios and 95% confidence intervals were used for reporting. Based on the surface under the cumulative ranking curves (SUCRA), the relative ranking probability of each group was generated.

RESULTS

Twenty-three RCTs met the inclusion criteria, and a total of 87,616 patients were enrolled. The bleeding safety of DOACs for stroke prevention and treatment in patients with AF was ranked from highest to lowest as follows: fatal bleeding: edoxaban (SUCRA,80.2), rivaroxaban (SUCRA,68.3), apixaban (SUCRA,48.5), dabigatran (SUCRA,40.0), VKAs (SUCRA,12.9); major bleeding: dabigatran (SUCRA,74.0), apixaban (SUCRA,71.5), edoxaban (SUCRA,66.5), rivaroxaban (SUCRA,22.7), VKAs (SUCRA,15.4); gastrointestinal bleeding: apixaban (SUCRA,55.9), VKAs (SUCRA,53.7), edoxaban (SUCRA,50.5), rivaroxaban (SUCRA,50.4), dabigatran (SUCRA,39.5); intracranial hemorrhage: dabigatran (SUCRA,84.6), edoxaban (SUCRA,74.1), apixaban (SUCRA,65.8), rivaroxaban (SUCRA,24.4), VKAs (SUCRA,1.1).

CONCLUSION

Based on current evidence, for stroke prevention and treatment in patients with AF, the most safe DOAC is edoxaban in terms of fatal bleeding; dabigatran in terms of major bleeding and intracranial hemorrhage and apixaban in terms of gastrointestinal bleeding. However, given the nature of indirect comparisons, more high-quality evidence from head-to-head comparisons is still needed to confirm them.

Oral Anticoagulant Use and Appropriateness in Elderly Patients with Atrial Fibrillation in Complex Clinical Conditions: ACONVENIENCE Study

Non-valvular atrial fibrillation (NVAF) is the most common arrhythmia in older patients. Although direct-acting oral anticoagulants (DOAC) are the antithrombotic treatment of choice, irrespective of age, certain factors may limit their use. The aim of the ACONVENIENCE study was to consult the opinion of a multidisciplinary panel of experts on the appropriateness of using OACs in elderly patients (>75 years) with NVAF associated with certain complex clinical conditions. A consensus project was performed on the basis of a systematic review of the literature, and application of a two-round Delphi survey. The agreement of 79 panellists on 30 Delphi-type statements was evaluated, and their opinion on the appropriateness of different oral anticoagulants in 16 complex clinical scenarios was assessed. A total of 27 consensus statements were agreed upon, including all statements addressing anticoagulation in older patients and in patients at high risk of bleeding complications, and most of those addressing frailty, dementia, risk of falling, and complex cardiac situations. It was almost unanimously agreed upon that advanced age should not influence the anticoagulation decision. Apixaban was the highest-rated therapeutic option in 14/16 situations, followed by edoxaban. There is a high degree of agreement on anticoagulation in older patients with NVAF. Age should not be the single limiting factor when prescribing OACs, and the decision should be made based on net clinical benefit and a comprehensive geriatric assessment. Apixaban, followed by edoxaban, was considered the most appropriate treatment in the various complex clinical situations examined.

Optimal stroke preventive strategy for patients aged 80 years or older with atrial fibrillation: a systematic review with traditional and network meta-analysis

BACKGROUND

An optimal antithrombotic strategy for patients aged 80 years or older with atrial fibrillation (AF) remains elusive.

OBJECTIVE

Using a systematic review with traditional and network meta-analysis, we investigated outcomes in AF patients ≥80 years treated with different antithrombotic strategies.

METHODS

We searched eligible randomised controlled trials (RCTs) and observational studies from MEDLINE, EMBASE, Cochrane Library and Web of Science databases from inception to 16 December 2021. Research comparing treatment outcomes of novel oral anticoagulants (NOACs), aspirin, vitamin K antagonists (VKAs) or no oral anticoagulant/placebo therapy in patients ≥80 years with AF were included. Outcomes were stroke or systemic embolism (SSE), major bleeding, all-cause mortality, intracranial bleeding (ICH) and gastrointestinal bleeding. Traditional and network meta-analyses were performed. Net clinical benefit integrating SSE and major bleeding was calculated.

RESULTS

Fifty-three studies were identified for analysis. In the meta-analysis of RCTs, risk of SSE (risk ratio [RR]: 0.82; 95% confidence interval [CI]: 0.73-0.99) and ICH (RR: 0.38; 95% CI: 0.28-0.52) was significantly reduced when NOACs were compared with VKAs. Network meta-analysis of RCTs demonstrated that edoxaban (P-score: 0.8976) and apixaban (P-score: 0.8528) outperformed other antithrombotic therapies by showing a lower major bleeding risk and better net clinical benefit. Both traditional and network meta-analyses from RCTs combining with observational studies showed consistent results.

CONCLUSIONS

In patients aged 80 years or older with AF, NOACs have better outcomes than VKAs regarding efficacy and safety profiles. Edoxaban and apixaban may be preferred treatment options since they are safer than other antithrombotic strategies.

Orally delivered rutin in lipid-based nano-formulation exerts strong antithrombotic effects by protein disulfide isomerase inhibition

Thrombosis occurs in both macrovasculature and microvasculature, causing various cardio-cerebral vascular diseases. The lack of effective and safe antithrombotic drugs leads to a public health crisis. Mounting evidence suggests that protein disulfide isomerase (PDI) plays a critical role in the initial stage of thrombus formation, motivating the research of the feasibility of PDI inhibitors as novel anti-thrombotics. Rutin, one of the most potent PDI inhibitors, was reported to suppress platelet aggregation and thrombosis in animal models, but further studies and clinical translation were restricted due to its low aqueous solubility and oral bioavailability. In this work, we fabricated rutin-loaded lipid-based nano-formulation (NanoR) and characterized their physical-chemical properties, release profiles, pharmacokinetic process, and pharmacodynamic function against thrombosis in macrovessels and microvessels. NanoR provided increased solubility and dissolution of rutin to achieve earlier Tmax and higher Cmax than the sodium salt of rutin (NaR) after oral gavage. Ex vivo studies demonstrated that NanoR significantly inhibited thrombin generation and clot formation in the plasma of mice. Importantly, such effect was reversed by exogenous recombinant PDI, demonstrating the specificity of the NanoR. In direct current-induced arterial thrombosis model and ferric chloride-induced microvascular thrombosis model, NanoR exhibited greatly enhanced antithrombotic activity compared with NaR. NanoR also showed good safety performance according to tail bleeding assay, global coagulation tests, and histological analysis. Overall, our current results indicated that NanoR offers a promising antithrombotic treatment with potential for clinical translation.

Mortality Rate in Upper Gastrointestinal Bleeding Associated with Anti-Thrombotic Therapy Before and During Covid-19 Pandemic

INTRODUCTION

During the last few years, a progressive higher proportion of patients have had upper gastrointestinal bleeding (UGIB) related to antithrombotic therapy. The introduction of direct oral anticoagulant (DOAC) and COVID-19 pandemic may change the incidence, mortality, and follow-up, especially in patients at high risk of bleeding.

PATIENTS AND METHODS

We studied the use of anti-thrombotic therapy (AT) in patients with upper gastrointestinal bleeding for 5 years (January 2017-December 2021) including Covid-19 pandemic period (March 2020-December 2021). We analyzed mortality rate, rebleeding rate and need for transfusion in patients with AT therapy compared with those without AT therapy and risk factors for mortality, and also the incidence of gastrointestinal bleeding in patients admitted for COVID-19 infection.

RESULTS

A total of 824 patients were admitted during Covid-19 pandemic period and 1631 before pandemic period; a total of 426 cases of bleeding were recorded in patients taking antithrombotic therapy and the frequency of antithrombotic therapy in patients with UGIB was higher in pandemic period (24.39% versus 13.8%). Unadjusted mortality was 12.21%, similar with patients with no antithrombotic treatment but age-adjusted mortality was 9.62% (28% lower). The rate of endoscopy was similar but fewer therapeutic procedures were required. Mean Hb level was 10% lower, and more than 60% of patients required blood transfusion.

CONCLUSION

Mortality was similar compared with patients with no antithrombotic therapy, fewer therapeutic endoscopies were performed and similar rebleeding rate and emergency surgery were noted. Hb level was 10% lower and a higher proportion of patients required blood transfusions. Mortality was higher in DOAC treatment group compared with VKA patients but with no statistical significance. The rate of upper gastrointestinal bleeding in Covid-19 positive hospitalized cases was 0.58%. The mortality risk in multivariate analysis was associated with GB score, with no endoscopy performed, with obscure and variceal bleeding and with LMWH versus VKA therapy.

Impact of comparative effectiveness research on Medicare coverage of direct oral anticoagulants

Aim: To evaluate the association of comparative effectiveness research with Medicare coverage of direct oral anticoagulants. Materials & methods: A literature review for direct oral anticoagulants was conducted from 2011 to 2017. Monthly prescription drug plan and formulary files (n = 28) were used to conduct change-point analysis and assess each outcome variable. Results: Up to 2013, studies showed that dabigatran was more effective than rivaroxaban. In 2015, apixaban was shown to be the safest and most effective drug in comparison with all direct oral anticoagulants. In 2016-2017, dabigatran and apixaban were shown to have similar efficacy. Approximately 75% of plans covered dabigatran under tier 3 until 2015. From 2011 to 2017, less than 30% of plans required prior authorizations, 50% imposed quantity limits and mean copayment was lowest for rivaroxaban. Conclusion: Consistent with comparative effectiveness research, Medicare plans covered apixaban more favorably and edoxaban less favorably. However, discrepancies in comparative effectiveness research translation were found for rivaroxaban and dabigatran.

Innate immune signaling and immunothrombosis: New insights and therapeutic opportunities

Activation of the coagulation cascade is a critical, evolutionarily conserved mechanism that maintains hemostasis by rapidly forming blood clots in response to blood-borne infections and damaged blood vessels. Coagulation is a key component of innate immunity since it prevents bacterial dissemination and can provoke inflammation. The term immunothrombosis describes the process by which the innate immune response drives aberrant coagulation, which can result in a lethal condition termed disseminated intravascular coagulation, often seen in sepsis. In this review, we describe the recently uncovered molecular mechanisms underlying inflammasome- and STING-driven immunothrombosis induced by bacterial and viral infections, culminating in tissue factor (TF) activation and release. Current anticoagulant therapeutics, while effective, are associated with a life-threatening bleeding risk, requiring the urgent development of new treatments. Targeting immunothrombosis may provide a safer option. Thus, we highlight preclinical tools which target TF and/or block canonical (NLRP3) or noncanonical (caspase-11) inflammasome activation as well as STING-driven TF release and discuss clinically approved drugs which block key immunothrombotic processes and, therefore, may be redeployed as safer anticoagulants.

Factor IX(a) inhibitors: an updated patent review (2003-present)

INTRODUCTION

Anticoagulation with no bleeding complications is the current objective of drug discovery programs in the area of treating and/or preventing thromboembolism. Despite the promises of therapeutics targeting factors XI(a) and XII(a), none has been approved thus far. Clinically used thrombin- and/or factor Xa-based anticoagulants continue to be associated with a significant bleeding risk which limits their safe use in a broad range of thrombotic patients. Research findings in animals and humans indicate that it is possible to target factor IX(a) (FIX(a)) to achieve anticoagulation with a limited risk of bleeding.

AREAS COVERED

A review of patents literature has retrieved >35 patents on the development of molecules targeting FIX(a) since 2003. Small molecules, antibodies, and aptamers have been developed to target FIX(a) to potentially promote effective and safer anticoagulation. Most of these agents are in the pre-clinical development phase and few have been tested in clinical trials.

EXPERT OPINION

FIX(a) system is being considered to develop new anticoagulants with fewer bleeding complications. Our survey indicates that the number of FIX(a)-targeting agents is mediocre. The agents under development are diverse. Although additional development is essential, moving one or more of these agents to the clinic will facilitate achieving better clinical outcomes.

Treatment of Cancer-Associated Venous Thromboembolism with Low-Molecular-Weight Heparin or Direct Oral Anticoagulants: Patient Selection, Controversies, and Caveats

The treatment of venous thromboembolism (VTE) in patients with cancer is challenging because these patients have increased risks of both recurrent VTE and major bleeding, along with patient-specific and cancer-related factors that influence the approach to treatment. Historically, anticoagulant therapy with low-molecular-weight heparin (LMWH), given for both initial and long-term treatment, has been the preferred approach recommended by practice guidelines. Most recently, the National Comprehensive Cancer Network (NCCN) guidelines indicate that the direct oral anticoagulants (DOACs) apixaban, edoxaban, or rivaroxaban are preferred for patients without gastric or gastroesophageal lesions. DOACs have been associated with an increased risk of major bleeding in patients with gastrointestinal and possibly genitourinary cancers, and DOACs should either not be used (especially in those with intact intraluminal tumors) or be used with caution in patients with these cancers. Fatal or life-threatening bleeding occurs with similar frequency with DOACs or LMWH, and most major bleeding with DOACs can be managed with transfusion and standard measures. The patient's willingness and ability to comply with LMWH injections, and their treatment preference, should also be considered. Patients with cancer who have VTE should be treated with anticoagulation for a minimum of 6 months. Anticoagulation should be continued indefinitely while cancer is active or under treatment or if there are persistent risk factors for recurrent VTE. This article summarizes the evidence from clinical trials of LMWH and DOACs that underpins the NCCN guideline recommendations, addresses several controversies and caveats regarding anticoagulant treatment, and offers evidence-based, practical suggestions on patient selection for treatment with DOACs. IMPLICATIONS FOR PRACTICE: Several randomized trials support the addition of direct oral anticoagulants (DOACs) to the therapeutic armamentarium for cancer-associated venous thromboembolism (VTE). These agents come with unique risks and patient- and cancer-specific variables that must be evaluated during the course of a patient's cancer care. This narrative review discusses findings from clinical trials of low-molecular-weight heparin and DOACs for the treatment of cancer-associated VTE, evidence that supports the recent National Comprehensive Cancer Network guideline recommendations. A personalized approach to treatment is proposed that addresses patient selection for treatment with DOACs, factors that influence efficacy and safety, controversies and caveats, and suggestions for their resolution in clinical practice.

Effectiveness and Safety of Oral Anticoagulants in Older Patients With Atrial Fibrillation: A Systematic Review and Meta-Analysis

Background and Objective

Atrial fibrillation (AF), the most common cardiac arrhythmia, typically increases with age. Oral anticoagulants (OACs) are the cornerstone of treatment to reduce the associated risk for systemic thromboembolism. Four large randomized controlled trials (RCTs) have shown that non-vitamin K antagonist oral anticoagulants (NOACs) are non-inferior to vitamin K antagonists (VKAs) in preventing stroke and systemic embolism, as well as regarding their risk for major bleeding. However, as vulnerable geriatric patients with AF were largely underrepresented in these trials, physicians are faced with the challenge of choosing the right anticoagulant for geriatric patients in real-life clinical practice. In this vulnerable patient group, NOACs tend to be underused or underdosed due to concerns of excessive fall-related intracranial bleeding, cognitive impairment, multiple drug-drug interactions, low body weight or impaired renal function. As life expectancy continues to rise worldwide, the number of geriatric patients substantially increases. Therefore, there is an urgent need for a critical appraisal of the added value of NOACs in geriatric patients with AF at high thromboembolic and bleeding risk.

Methods and Results

This systematic review provides an overview of the literature on the impact of increased age (≥75 years), multimorbidity, polypharmacy, increased falling risk, frailty and dementia on the effectiveness and safety of NOACs as compared to VKAs, after searching the Medline database. Moreover, a meta-analysis on the impact of increased age ≥75 years old was performed after pooling results from 6 post hoc analyses of RCTs and 6 longitudinal observational cohort studies, highlighting the superior effectiveness (hazard ratio (HR) 0.83, 95% confidence interval (CI) [0.74–0.94] for stroke/SE; HR 0.77, 95%CI [0.65–0.92] for mortality) and non-inferior safety (HR 0.93, 95%CI [0.86–1.01] for major bleeding; HR 0.58, 95%CI [0.50–0.67] for intracranial bleeding; HR 1.17, 95%CI [0.99–1.38] for gastrointestinal bleeding) of NOACs versus VKAs in older AF patients.

Conclusion

Across geriatric subgroups, apixaban was consistently associated with the most favourable benefit-risk profile and should therefore be preferred in geriatric patients with AF. However, research gaps on the impact of increased falling risk, frailty and baseline dementia were identified, requiring careful consideration while awaiting more results.

A Systematic Review of Network Meta-Analyses and Real-World Evidence Comparing Apixaban and Rivaroxaban in Nonvalvular Atrial Fibrillation

There is no direct evidence comparing the 2 most commonly prescribed direct oral anticoagulants, apixaban and rivaroxaban, used for stroke prevention in nonvalvular atrial fibrillation (NVAF). A number of network meta-analyses (NMAs) of randomized control trials and real-world evidence (RWE) studies comparing the efficacy, effectiveness, and safety of apixaban and rivaroxaban have been published; however, a comprehensive evidence review across the available body of evidence is lacking. In this study, we aimed to systematically review and evaluate the clinical outcomes of apixaban and rivaroxaban using a combination of data gleaned from both NMAs and RWE studies. The review identified 21 NMAs and 5 RWE studies. The data demonstrated that apixaban was associated with fewer major bleeding events compared to rivaroxaban. There was no difference in the efficacy/effectiveness profiles between these treatments. Bleeding is a serious complication of anticoagulation therapy for the management of NVAF, and is associated with increased rates of hospitalization, morbidity, mortality, and health-care expenditure. The majority of studies in this comprehensive evidence review suggests that apixaban has a lower risk of major bleeding events compared to rivaroxaban in patients with NVAF.

The problem of underdosing with direct-acting oral anticoagulants in elderly patients with nonvalvular atrial fibrillation

Unless contraindicated, anticoagulant therapy should be prescribed to elderly patients with atrial fibrillation. Direct-acting oral anticoagulants (DOACs) are superior to vitamin K antagonists for preventing stroke. This, together with their higher net clinical benefit, makes DOACs the treatment of choice in this population. However, due to the concerns about bleeding and the need for dose adjustment based on clinical variables, underdosing of DOACs is common and the risk of stroke high. Drugs with more easily adjusted doses are likely associated with a lower risk of dosing errors and, therefore, a greater protective effect. Correct dosing can ensure a maximal net benefit of DOACs in elderly patients with atrial fibrillation.

Atrial Fibrillation in Older People: Concepts and Controversies

Atrial fibrillation (AF) is the commonest cardiac rhythm abnormality and has a significant disease burden. Amongst its devastating complications is stroke, the risk of which increases with age. The stroke risk in an older person with AF is therefore tremendous, and oral-anticoagulation (OAC) therapy is central to minimizing this risk. The presence of age-associated factors such as frailty and multi-morbidities add complexity to OAC prescription decisions in older patients and often, OAC is needlessly withheld from them despite a lack of evidence to support this practice. Generally, this is driven by an over-estimation of the bleeding risk. This review article provides an overview of the concepts and controversies in managing AF in older people, with respect to the existing evidence and current practice. A literature search was conducted on Pubmed and Cochrane using keywords, and relevant articles published by the 1st of May 2019 were included. The article will shed light on common misconceptions that appear to serve as rationale for precluding OAC and focus on clinical considerations that may aid OAC prescription decisions where appropriate, to optimize AF management using an integrated, multi-disciplinary care approach. This is crucial for all patients, particularly older individuals who are most vulnerable to the deleterious consequences of this condition.

Factor Xa inhibitors versus vitamin K antagonists for preventing cerebral or systemic embolism in patients with atrial fibrillation

BACKGROUND

Factor Xa inhibitors and vitamin K antagonists (VKAs) are now recommended in treatment guidelines for preventing stroke and systemic embolic events in people with atrial fibrillation (AF). This is an update of a Cochrane review previously published in 2013.

OBJECTIVES

To assess the effectiveness and safety of treatment with factor Xa inhibitors versus VKAs for preventing cerebral or systemic embolic events in people with AF.

SEARCH METHODS

We searched the trials registers of the Cochrane Stroke Group and the Cochrane Heart Group (September 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) (August 2017), MEDLINE (1950 to April 2017), and Embase (1980 to April 2017). We also contacted pharmaceutical companies, authors and sponsors of relevant published trials. We used outcome data from marketing authorisation applications of apixaban, edoxaban and rivaroxaban that were submitted to regulatory authorities in Europe and the USA.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that directly compared the effects of long-term treatment (lasting more than four weeks) with factor Xa inhibitors versus VKAs for preventing cerebral and systemic embolism in people with AF.

DATA COLLECTION AND ANALYSIS

The primary efficacy outcome was the composite endpoint of all strokes and systemic embolic events. Two review authors independently extracted data, and assessed the quality of the trials and the risk of bias. We calculated a weighted estimate of the typical treatment effect across trials using the odds ratio (OR) with 95% confidence interval (CI) by means of a fixed-effect model. In case of moderate or high heterogeneity of treatment effects, we used a random-effects model to compare the overall treatment effects. We also performed a pre-specified sensitivity analysis excluding any open-label studies.

MAIN RESULTS

We included data from 67,688 participants randomised into 13 RCTs. The included trials directly compared dose-adjusted warfarin with either apixaban, betrixaban, darexaban, edoxaban, idraparinux, idrabiotaparinux, or rivaroxaban. The majority of the included data (approximately 90%) was from apixaban, edoxaban, and rivaroxaban.The composite primary efficacy endpoint of all strokes (both ischaemic and haemorrhagic) and non-central nervous systemic embolic events was reported in all of the included studies. Treatment with a factor Xa inhibitor significantly decreased the number of strokes and systemic embolic events compared with dose-adjusted warfarin in participants with AF (OR 0.89, 95% CI 0.82 to 0.97; 13 studies; 67,477 participants; high-quality evidence).Treatment with a factor Xa inhibitor significantly reduced the number of major bleedings compared with warfarin (OR 0.78, 95% CI 0.73 to 0.84; 13 studies; 67,396 participants; moderate-quality evidence). There was, however, statistically significant and high heterogeneity (I2 = 83%). When we repeated this analysis using a random-effects model, it did not show a statistically significant decrease in the number of major bleedings (OR 0.88, 95% CI 0.66 to 1.17). A pre-specified sensitivity analysis excluding all open-label studies showed that treatment with a factor Xa inhibitor significantly reduced the number of major bleedings compared with warfarin (OR 0.75, 95% CI 0.69 to 0.81), but high heterogeneity was also observed in this analysis (I2 = 72%). The same sensitivity analysis using a random-effects model also showed a statistically significant decrease in the number of major bleedings in participants treated with factor Xa inhibitors (OR 0.76, 95% CI 0.60 to 0.96).Treatment with a factor Xa inhibitor significantly reduced the risk of intracranial haemorrhages (ICHs) compared with warfarin (OR 0.50, 95% CI 0.42 to 0.59; 12 studies; 66,259 participants; high-quality evidence). We observed moderate, but statistically significant heterogeneity (I2 = 55%). The pre-specified sensitivity analysis excluding open-label studies showed that treatment with a factor Xa inhibitor significantly reduced the number of ICHs compared with warfarin (OR 0.47, 95% CI 0.40 to 0.56), with low, non-statistically significant heterogeneity (I2 = 27%).Treatment with a factor Xa inhibitor also significantly reduced the number of all-cause deaths compared with warfarin (OR 0.89, 95% 0.83 to 0.95; 10 studies; 65,624 participants; moderate-quality evidence).

AUTHORS' CONCLUSIONS

Treatment with factor Xa inhibitors significantly reduced the number of strokes and systemic embolic events compared with warfarin in people with AF. The absolute effect of factor Xa inhibitors compared with warfarin treatment was, however, rather small. Factor Xa inhibitors also reduced the number of ICHs, all-cause deaths and major bleedings compared with warfarin, although the evidence for a reduction in the latter is less robust.

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

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

Effectiveness and patient safety of platelet aggregation inhibitors in the prevention of cardiovascular disease and ischemic stroke in older adults - a systematic review

BACKGROUND

Platelet aggregation inhibitors (PAI) are among the most frequently prescribed drugs in older people, though evidence about risks and benefits of their use in older adults is scarce. The objectives of this systematic review are firstly to identify the risks and benefits of their use in the prevention and treatment of vascular events in older adults, and secondly to develop recommendations on discontinuing PAI in this population if risks outweigh benefits.

METHODS

Staged systematic review consisting of three searches. Searches 1 and 2 identified systematic reviews and meta-analyses. Search 3 included controlled intervention and observational studies from review-articles not included in searches 1 and 2. All articles were assessed by two independent reviewers regarding the type of study, age of participants, type of intervention, and clinically relevant outcomes. After data extraction and quality appraisal we developed recommendations to stop the prescribing of specific drugs in older adults following the Grading of Recommendations Assessment Development and Evaluation (GRADE) methodology.

RESULTS

Overall, 2385 records were screened leading to an inclusion of 35 articles reporting on 22 systematic reviews and meta-analyses, 11 randomised controlled trials, and two observational studies. Mean ages ranged from 57.0 to 84.6 years. Ten studies included a subgroup analysis by age. Overall, based on the evaluated evidence, three recommendations were formulated. First, the use of acetylsalicylic acid (ASA) for primary prevention of cardiovascular disease (CVD) in older people cannot be recommended due to an uncertainty in the risk-benefit ratio (weak recommendation; low quality of evidence). Secondly, the combination of ASA and clopidogrel in patients without specific indications should be avoided (strong recommendation; moderate quality of evidence). Lastly, to improve the effectiveness and reduce the risks of stroke prevention therapy in older people with atrial fibrillation (AF) and a CHA₂DS₂-VASc score of ≥ 2, the use of ASA for the primary prevention of stroke should be discontinued in preference for the use of oral anticoagulants (weak recommendation; low quality of evidence).

CONCLUSIONS

The use of ASA for the primary prevention of CVD and the combination therapy of ASA and clopidogrel for the secondary prevention of vascular events in older people may not be justified. The use of oral anticoagulants instead of ASA in older people with atrial fibrillation may be recommended. Further high quality studies with older adults are needed.

Effect of a combined education and eHealth programme on the control of oral anticoagulation patients (PORTALS study): a parallel cohort design in Dutch primary care

OBJECTIVES

To analyse the effect on therapeutic control and self-management skills of the implementation of self-management programmes, including eHealth by e-learning versus group training.

SETTING

Primary Care Thrombosis Service Center.

PARTICIPANTS

Of the 247 oral anticoagulation therapy (OAT) patients, 63 started self-management by e-learning, 74 self-management by group training and 110 received usual care.

INTERVENTION AND METHODS

Parallel cohort design with two randomised self-management groups (e-learning and group training) and a group receiving usual care. The effect of implementation of self-management on time in therapeutic range (TTR) was analysed with multilevel linear regression modelling. Usage of a supporting eHealth platform and the impact on self-efficacy (Generalised Self-Efficacy Scale (GSES)) and education level were analysed with linear regression analysis. After intervention, TTR was measured in three time periods of 6 months.

MAIN OUTCOME MEASURES

(1) TTR, severe complications,(2) usage of an eHealth platform,(3) GSES, education level.

RESULTS

Analysis showed no significant differences in TTR between the three time periods (p=0.520), the three groups (p=0.460) or the groups over time (p=0.263). Comparison of e-learning and group training showed no significant differences in TTR between the time periods (p=0.614), the groups (p=0.460) or the groups over time (p=0.263). No association was found between GSES and TTR (p=0.717) or education level and TTR (p=0.107). No significant difference was found between the self-management groups in usage of the platform (0-6 months p=0.571; 6-12 months p=0.866; 12-18 months p=0.260). The percentage of complications was low in all groups (3.2%; 1.4%; 0%).

CONCLUSIONS

No differences were found between OAT patients trained by e-learning or by a group course regarding therapeutic control (TTR) and usage of a supporting eHealth platform. The TTR was similar in self-management and regular care patients. With adequate e-learning or group training, self-management seems safe and reliable for a selected proportion of motivated vitamin K antagonist patients.

TRIAL REGISTRATION NUMBER

NTR3947.

Safety profile of the direct oral anticoagulants: an analysis of the WHO database of adverse drug reactions

AIM

Direct oral anticoagulants (DOACs) have shown noninferiority to warfarin for stroke prevention in nonvalvular atrial fibrillation (AF) and a more promising safety profile. Unanswered safety aspects remain to be addressed and available evidence on the risk associated with these drugs are conflicting. In order to contribute to the debate on their safety profile, we conducted a comparative analysis of the reports of suspected adverse drug reactions (ADRs) associated with DOACs in VigiBase.

METHODS

Study based on reports of suspected ADRs held in VigiBase as at December 2014, in which a DOAC or warfarin were administered in patients with nonvalvular AF and listed as suspected/interacting drugs. Medical Dictionary for Regulatory Activities was used to classify ADRs. Reporting odds ratio (ROR) with 95% confidence interval were calculated. Results with P ≤ 0.05 were statistically significant.

RESULTS

We retrieved 32 972 reports. We identified 204 ADRs with a ROR >1 (P ≤ 0.05) and we focused on 105 reactions. Positive ROR emerged for DOACs and gastrointestinal haemorrhage compared with warfarin [(1.6 (1.47-1.75)], but no disproportionality with cerebral haemorrhage was found [0.31 (0.28-0.34)]. We identified other potential signals that have not been associated with DOACs previously.

CONCLUSIONS

As well as premarketing authorization clinical trial studies, we found a reduced risk of intracranial haemorrhage, but an increased risk of gastrointestinal haemorrhage in patients treated with DOACs compared to warfarin. We provide new data and we highlight several differences between the three novel oral anticoagulants, in the rate and type of ADRs occurred.

Rationale and Design for a Randomized Comparison of Efficacy and Safety between Aspirin and Clopidogrel in Atrial Fibrillation Patients with Low Stroke Risk: CESAC-AF trial

BACKGROUND

Atrial fibrillation (AF) increases the risk of thromboembolic stroke. An oral anticoagulant should be administrated to prevent stroke in patients with moderate stroke risk (ie, CHA₂DS₂-VASc score>2). If the stroke risk is low (i.e. the score=1), however, antiplatelet agent such as aspirin is widely used. Aspirin can cause peptic ulcer disease (PUD) while its alternative, clopidogrel, theoretically does not.

OBJECTIVE

To elucidate the efficacy and safety between aspirin and clopidogrel, a multicenter randomized controlled trial was designed in AF patients with low stroke risk.

METHODS

According to sample size estimation based on previous literature, a total of 1560 AF patients with low stroke risk will be randomly assigned into 4 different groups dependent upon initial esophagogastroduodenoscopy (EGD) results: two mono-antiplatelet treatment groups with either aspirin 100mg or clopidogrel 75mg for 1year; two antiplatelet agent and proton pump inhibitor (PPI) combination groups. Follow-up EGD will be performed at 1year.

RESULTS

The clinical follow-up will be performed for 1year after enrollment. The primary efficacy endpoint is to compare the annual stroke rate between aspirin and clopidogrel treatment groups. The primary safety endpoint is to compare the prevalence of drug-induced gastrointestinal (GI) and intracranial hemorrhage and upper-GI response including PUD based on EGD after 1year.

CONCLUSIONS

This trial will determine whether clopidogrel is noninferior in stroke prevention and superior in reduction of GI events including PUD to aspirin in AF patients with low stroke risk. (ClinicalTrials.gov: NCT02960126).

Predictive performance of the CHA2DS2-VASc rule in atrial fibrillation: a systematic review and meta-analysis

Essentials The widely recommended CHA2DS2-VASc shows conflicting results in contemporary validation studies. We performed a systematic review and meta-analysis of 19 studies validating CHA2DS2-VASc. There was high heterogeneity in stroke risks for different CHA2DS2-VASc scores. This was not explained by differences between setting of care, or by performing meta-regression.

SUMMARY

Background The CHA2DS2-VASc decision rule is widely recommended for estimating stroke risk in patients with atrial fibrillation (AF), although validation studies show ambiguous and conflicting results. Objectives To: (i) review existing studies validating CHA2DS2-VASc in AF patients who are not (yet) anticoagulated; (ii) meta-analyze estimates of stroke risk per score; and (iii) explore sources of heterogeneity across the validation studies. Methods We performed a systematic literature review and random effects meta-analysis of studies externally validating CHA2DS2-VASc in AF patients not receiving anticoagulants. To explore between-study heterogeneity in stroke risk, we stratified studies to the clinical setting in which patient enrollment started, and performed meta-regression. Results In total, 19 studies were evaluated, with over two million person-years of follow-up. In studies recruiting AF patients in hospitals, stroke risks for scores of 0, 1 and 2 were 0.4% (approximate 95% prediction interval [PI] 0.2-3.2%), 1.2% (95% PI 0.1-3.8%), and 2.2% (95% PI 0.03-7.8%), respectively. These were consistently higher than those in studies recruiting patients from the open general population, with risks of 0.2% (95% PI 0.0-0.9%), 0.7% (95% PI 0.3-1.2%) and 1.5% (95% PI 0.4-3.3%) for scores of 0, 1, and 2, respectively. Heterogeneity, as reflected by the wide PIs, could not be fully explained by meta-regression. Conclusions Studies validating CHA2DS2-VASc show high heterogeneity in predicted stroke risks for different scores.

Risk of gastrointestinal bleeding during anticoagulant treatment

INTRODUCTION

Gastrointestinal bleeding (GIB) is a major problem in patients on oral anticoagulation therapy. This issue has become even more pressing since the introduction of direct oral anticoagulants (DOACs) in 2009. Areas covered: Here we review current evidence related to GIB associated with oral anticoagulants, focusing on randomized controlled trials, meta-analyses, and post-marketing observational studies. Dabigatran 150 mg twice daily and rivaroxaban 20 mg once daily increase the risk of GIB compared to warfarin. The risk increase with edoxaban is dose-dependent, while apixaban shows apparently, no increased risk. We summarize what is known about GIB risk factors for individual anticoagulants, the location of GIB in patients taking these compounds, and prevention strategies that lower the risk of GIB. Expert opinion: Recently there has been an important shift in the clinical presentation of GIB. Specifically, upper GIB has decreased with the decreased incidence of peptic ulcers due to the broad use of proton pump inhibitors and the decreased prevalence of H. pylori infections. In contrast, the incidence of lower GIB has increased, due in part to colonic diverticular bleeding and angiodysplasia in the elderly. In this population, the addition of oral anticoagulation therapy, especially DOACs, seems to increase the risk of lower GIB.

Gastrointestinal Safety of Direct Oral Anticoagulants: A Large Population-Based Study

BACKGROUND & AIMS

Direct oral anticoagulant (DOAC) agents increase the risk of gastrointestinal (GI) bleeding. We investigated which DOAC had the most favorable GI safety profile and compared differences among these drugs in age-related risk of GI bleeding.

METHODS

We conducted a retrospective, propensity-matched study using administrative claims data from the OptumLabs Data Warehouse of privately insured individuals and Medicare Advantage enrollees. We created 3 propensity-matched cohorts of patients with non-valvular atrial fibrillation with incident exposure to dabigatran, rivaroxaban, or apixaban from October 1, 2010 through February 28, 2015. We compared data on rivaroxaban vs dabigatran for 31,574 patients, data on apixaban vs dabigatran for 13,084 patients, and data on apixaban vs rivaroxaban for 13,130 patients. Cox proportional hazards models, stratified by age, were used to estimate rates of total GI bleeding.

RESULTS

Baseline characteristics were well balanced among sub-cohorts. GI bleeding occurred more frequently in patients given rivaroxaban than dabigatran (hazard ratio [HR], 1.20; 95% confidence interval [CI], 1.00-1.45). Apixaban was associated with a lower risk of GI bleeding than dabigatran (HR, 0.39; 95% CI, 0.27-0.58; P < .001) or rivaroxaban (HR, 0.33; 95% CI, 0.22-0.49; P < .001). Rates of events for all DOACs increased among patients 75 years or older. Apixaban had a lower risk of association with GI bleeding in the very elderly than dabigatran (HR, 0.45; 95% CI, 0.29-0.71) or rivaroxaban (HR, 0.39; 95% CI, 0.25-0.61). Median times to GI bleeding were <90 days for apixaban and rivaroxaban and <120 days for dabigatran.

CONCLUSIONS

In a population-based study of patients receiving DOAC agents, we found apixaban had the most favorable GI safety profile and rivaroxaban the least favorable profile. GI bleeding events among patient aged 75 years or older taking DOACs increased with age; the risk was greatest among persons 75 years. Apixaban had the most favorable GI safety profile among all age groups.

Comparative Efficacy of Clinical Events Prevention of Five Anticoagulants in Patients With Atrial Fibrillation (A Network Meta-Analysis)

Atrial fibrillation (AF) ranks the most prevailing type of cardiac rhythm disorder and AF patients are associated with a significantly increased risk of stroke compared to others. This study is designed to assess the relative efficacy of several clinical events prevention anticoagulants in patients with AF. Conventional pairwise meta-analysis was performed with fixed-effect model initially, then network meta-analysis was performed with random-effects model within results illustrated by cumulative odds ratios (ORs) and corresponding 95% credible interval (CrI). The rank probabilities of each treatment outcomes were summarized by the surface under the cumulative ranking curve (SUCRA). We conducted a systematic review and collected key clinical data from 37 studies with respect to 5 anticoagulant treatments for AF. Patients treated with rivaroxaban and apixaban are associated with a reduced risk of stroke compared to those treated with warfarin (OR 0.72, 95% CrI 0.53 to 0.88; OR 0.68, 95% CrI 0.48 to 0.91). Rivaroxaban (SUCRA = 0.712) appears to be the most preferable one with respect to vascular events, and both apixaban (SUCRA = 0.720) and rivaroxaban (SUCRA = 0.678) are preferable to others with respect to stroke. Dabigatran outperforms others with respect to the outcome of mortality (SUCRA = 0.695), hemorrhage events (SUCRA = 0.747), and myocardial infarction (SUCRA = 0.620). In conclusion, dabigatran has a noticeable and comprehensive advantage compared to others with respect to preventing several complications including hemorrhage events, myocardial infarction, and mortality. In addition, apixaban may be the best choice of preventing stroke, and rivaroxaban is more preferable to others with respect to preventing vascular events.

Gastrointestinal bleeding secondary to the new anticoagulants

PURPOSE OF REVIEW

To quantify direct oral anticoagulants (DOACs) related gastrointestinal bleeding (GIB), characterize patients at greatest risk and provide a pragmatic approach for the management of these drugs. This review will also summarize risk-management strategies and highlight evolving areas of clinical knowledge.

RECENT FINDINGS

DOACs permit anticoagulation with predictable dosing without the need for routine serum monitoring. Since their availability on the market, they have quickly emerged as a popular alternative for patients requiring short-term and lifelong anticoagulation. However, they are associated with an increased risk of GIB when compared with warfarin; thus, gastroenterologists must be prepared to manage DOAC-related GIB and prevent drug-related complications. This review will focus on acute and elective periendoscopic DOAC management, high-risk clinical groups for DOAC-related GIB, quantification of DOAC levels, use of reversal agents and minimization of thromboembolic risk associated with temporary interruption.

SUMMARY

This review will highlight pragmatic strategies for the treatment of DOAC-related bleeding and the prevention of postendoscopic DOAC bleeding. It will address new and evolving areas of periendoscopic management and identify knowledge gaps requiring further research to inform clinical practice.

Efficacy and Safety of Direct Oral Anticoagulants Compared to Warfarin in Prevention of Thromboembolic Events Among Elderly Patients with Atrial Fibrillation

Direct oral anticoagulants (DOACs), previously also known as novel oral anticoagulants (NOACs), have increased the therapeutic options for stroke prevention in atrial fibrillation (AF). Previous studies comparing their relative efficacy and safety do not address age-related differences, such as comorbidities and physical and social boundaries. This review aimed to summarize and compare the clinical and safety outcomes of DOACs and warfarin for stroke prevention in AF in the elderly population (≥ 65 years). We searched PubMed for randomized controlled trials and meta-analyses that compared DOACs and warfarin in elderly patients with AF. Stroke and systemic embolism (SSE) and major bleeding (MB) were primary outcomes. Secondary outcomes included ischemic stroke, all-cause mortality, intracranial bleeding, and gastrointestinal bleeding. Of 66 studies identified, one randomized control trial (RCT) and one meta-analysis were included. DOACs were at least as effective at reducing the risk of SSE as warfarin. DOACs demonstrated a minimal benefit for ischemic stroke (dabigatran, 110 mg, relative risk (RR) 1.08; edoxaban, 60 mg, RR 1.00; and apixaban, 5 mg, RR 0.99). DOACs associated with decreased risk of MB relative to warfarin include dabigatran, 110 mg; apixaban, 5 mg; and edoxaban, 60 mg (RR 0.80, 0.70, and 0.80, respectively), while dabigatran, 150 mg, and rivaroxaban, 20 mg, increased risk (RR 0.79 - 0.83, respectively). Dabigatran, 110 mg and 150 mg doses, and edoxaban increased the risk of gastrointestinal bleeding (RR 1.04, 1.12, and 1.23, respectively). Lower rates of SSE and intracranial bleeding were seen with DOACs compared to warfarin. Dabigatran, 150 mg, and rivaroxaban, 20 mg, were associated with higher MB in older elderly compared to warfarin. DOACs may be attractive alternatives to warfarin, but further studies are needed to make clinical recommendations.

Cost-effectiveness modelling of novel oral anticoagulants incorporating real-world elderly patients with atrial fibrillation

BACKGROUND

Novel oral anticoagulants (NOACs) expand the treatment options for patients with atrial fibrillation (AF). Their benefits need to be weighed against the risk-benefit ratio in real-world elderly patients, prompting this cost-effectiveness study of NOACs (apixaban, dabigatran, edoxaban and rivaroxaban), warfarin and aspirin for stroke prevention in AF.

METHODS

Applying effectiveness estimates from a network meta-analysis involving over 800,000 patients from randomised controlled trials and observation studies, our Markov model projected cost and health outcomes for a cohort of 65-year-old AF patients over a life-time. We performed subgroup analysis stratified by age (65-74 and ≥75years), with further analysis limited to observational studies involving dabigatran and rivaroxaban.

RESULTS

Compared to warfarin, NOACs (except dabigatran 110) were associated with incremental cost-effectiveness ratios ranging from USD 24,476 to USD 41,448 that were within cost-effectiveness threshold of USD 49,700 (one gross domestic product per capita in Singapore in 2015). Aspirin regimens were dominated. In elderly aged ≥75years, cost effectiveness of NOACs (except apixaban) decreased, owing to worsened performance in safety profile. Analysis limited to observational studies revealed that dabigatran 150 and rivaroxaban were not cost-effective, reflecting increased bleeding risks in non-controlled settings. Threshold analyses revealed that apixaban was no longer cost-effective at two to three times higher bleeding risk.

CONCLUSIONS

Whilst NOACs are cost-effective in the younger elderly compared to warfarin, their benefits appear to be offset by worsened risk profile in older elderly, especially in non-controlled settings. Decisions on appropriate AF treatment should balance treatment-related benefits, risks, and patient preference.