Ischaemic stroke and bleeding rates in ‘real-world’ atrial fibrillation patients

Comparative Bleeding Risk of Brand Vs Generic Rivaroxaban in Elderly Inpatients with Atrial Fibrillation

Objective

Atrial fibrillation (AF) is the most common abnormal heart rhythm in elderly patients. Rivaroxaban has been widely used for stroke prevention. The anticoagulant response to rivaroxaban increases with age, which may make elderly patients susceptible to adverse outcomes resulting from small differences in bioavailability between generic and brand products.

Methods

We designed a cohort study of ≥65-year-old inpatients with AF. Sociodemographic and laboratory measures of qualified patients who received brand or generic rivaroxaban for at least 72 hours at the study hospital from January 2021 to June 2023 were collected retrospectively. The primary outcome was the incidence of bleeding.

Results

A total of 1008 qualifying patients were included for analysis, with 626 (62.1%) receiving brand rivaroxaban and 382 (37.9%) receiving generic rivaroxaban. After propensity score matching and weighting to account for confounders, the odds ratios comparing brand vs generic rivaroxaban (95% confidence intervals) for the bleeding was 1.15 (0.72-1.82). Results from subgroup analyses of patients with age ≥85, HAS-BLED score ≥ 3, containment of antiplatelet drugs, and female patients were consistent with the primary analysis.

Conclusion

It provides evidence regarding the clinical safety outcome of generic rivaroxaban in the elderly AF population that may be particularly susceptible to adverse outcomes resulting from small allowable differences in pharmacokinetics.

Underutilization of anticoagulants in patients with nonvalvular atrial fibrillation in the era of non-vitamin K antagonist oral anticoagulants

Background

Non-vitamin K antagonist oral anticoagulants (NOACs) are preferred over vitamin K antagonists (VKAs) as oral anticoagulant (OAC) therapy in patients with nonvalvular atrial fibrillation (NVAF). This study aimed to estimate the current status and risk factors of OAC underutilization in the NOAC era.

Method

A cross-sectional study using nationwide claims data was conducted. Elderly patients with NVAF at an increased risk of stroke were selected as candidates for OAC therapy before the index date (July 1, 2018). The status of anticoagulant utilization on the index date and factors influencing the use of anticoagulants was investigated in these patients.

Results

Of the 11,056 patients with NVAF who were eligible for OAC therapy, 7238 (65.5%) were receiving OAC on the index date, and 6302 (87.1%) were receiving NOACs. Patients aged ≥ 75 years had higher anticoagulant utilization than those aged 65–69 years. Among comorbid diseases, while hypertension was the most influential positive factor (odds ratio [OR] = 1.644; confidence interval [CI] = 1.445–1.869) in OAC utilization, severe renal disease was the most influential negative factor (OR = 0.289; CI = 0.200–0.416). Aspirin use had a significantly low OR (OR = 0.097; CI = 0.085–0.110) of anticoagulant use. OAC use was approximately 1.5 times higher in patients with persistent or permanent AF than in those with paroxysmal AF.

Conclusion

Approximately one-third of patients who are recommended anticoagulation therapy do not take OACs, even though the use of NOACs has become more common. It should be widely recognized that aspirin cannot be an alternative to OACs, and anticoagulant therapy should be actively implemented.

Clinical Outcomes of Very Elderly Patients With Atrial Fibrillation Receiving On-label Doses of Apixaban: J-ELD AF Registry Subanalysis

Background

Increasing age predisposes patients with atrial fibrillation to both thromboembolic and bleeding events; however, data on outcomes of very elderly patients (aged ≥85 years) receiving appropriate antithrombotic therapy are still limited.

Methods and Results

The J‐ELD AF (Multicenter Prospective Cohort Study to Investigate the Effectiveness and Safety of Apixaban in Japanese Elderly Atrial Fibrillation Patients) Registry is a multicenter prospective observational study of Japanese patients with nonvalvular atrial fibrillation aged ≥75 years taking on‐label doses (standard dose of 5 mg BID or reduced dose of 2.5 mg BID) of apixaban. The entire cohort (3031 patients from 110 institutions) was divided into 3 age groups: 75 to 79 years (n=1068, 35.2%), 80 to 84 years (n=1120, 37.0%), and ≥85 years (n=843, 27.8%). The event incidence rates (/100 person‐years) were 1.40, 1.55, and 1.95 for stroke or systemic embolism (log‐rank P=0.65); 1.70, 1.55, and 2.61 for bleeding requiring hospitalization (log‐rank P=0.33); 2.09, 2.60, and 5.29 for total deaths (log‐rank P<0.001); and 0.40, 1.06, and 1.55 for cardiovascular deaths (log‐rank P=0.045), respectively. After adjusting for confounders using a Cox regression analysis, age ≥85 years was identified as an independent risk of total death (hazard ratio, 1.89; 95% CI, 1.10–3.26 [P=0.022]), but not of stroke or systemic embolism, bleeding requiring hospitalization, or cardiovascular death.

Conclusions

Although mortality increased with age, age ≥85 years was not a significant risk of stroke or systemic embolism, bleeding requiring hospitalization, or cardiovascular death in Japanese patients with nonvalvular atrial fibrillation taking on‐label doses of apixaban.

Registration

URL: https://www.umin.ac.jp/ctr; Unique identifier: UMIN000017895.

Impact of prescription patterns of antithrombotic treatment on atrial fibrillation-related ischemic stroke

OBJECTIVE

To analyze the temporal trends of atrial fibrillation (AF)-related ischemic stroke (IS) and their relationship with the prescription patterns of antithrombotic treatment from 2013 to 2019 in the Health Assistance Area of a regional hospital.

METHODS

First, a retrospective ecological study of aggregate data to analyze the annual incidence of IS between 2013 and 2019 was performed. Second, we selected those patients diagnosed with AF between 2013 and 2019 and performed a retrospective longitudinal study to assess the role of antithrombotic therapy in the development of AF-related IS.

RESULTS

During this period, whereas the annual incidence of IS remained stable (from 1.3 in 2013 to 1.2 cases per 1000 inhabitants in 2019; adjusted P for trend .829), the annual incidence of AF-related IS decreased over time (from 23.8 to 18.8 cases per 1000 inhabitants, respectively; adjusted P for trend .001). Among AF patients, the use of direct oral anticoagulants increased from 5.5% to 46.8%, while the prescription of antiplatelets and vitamin K antagonists decreased from 21.9% to 6.0% and from 63.8% to 36.1%, respectively. Overall, the use of oral anticoagulants increased from 69.3% to 82.9%; p < .001. Patients under antiplatelet agents had a higher probability of presenting IS than those patients taking oral anticoagulants, either vitamin K antagonists or direct oral anticoagulants (adjusted OR 1.89; 95% CI 1.52-2.37; p < .001).

CONCLUSIONS

The prescription of oral anticoagulants, particularly direct oral anticoagulants, has increased from 2013 to 2019 in our Health Assistance Area. This increase might partially explain the reduction in AF-related IS.

Biomarkers Associated with Bleeding Risk in the Setting of Atrial Fibrillation

BACKGROUND

Prevention of thromboembolic disease, mainly stroke, with oral anticoagulants remains a major therapeutic goal in patients with atrial fibrillation. Unfortunately, despite the high efficacy, anticoagulant therapy is associated with a significant risk of, frequently catastrophic, and hemorrhagic complications. Among different clinical and laboratory parameters related to an increased risk of bleeding, several biological markers have been recognized and various risk scores for bleeding have been developed.

OBJECTIVES/METHODS

The aim of the present study is to review current evidence regarding the different biomarkers associated with raised bleeding risk in atrial fibrillation.

RESULTS

Data originating from large cohorts or the recent large-scale trials of atrial fibrillation have linked numerous individual biomarkers to an increased bleeding risk. Such a relation was revealed for markers of cardiac physiology, such as troponin, BNP and NT-proBNP, markers of renal function, such as GFR and Cystatin or hepatic function, markers involving the system of coagulation, such as D-dimer and Von Willebrand factor, hematologic markers, such as low haemoglobin or low platelets, inflammatory markers, such as interleukin-6, other factors such as GDF-15 and vitamin-E and finally genetic polymorphisms. Many such biomarkers are incorporated in the bleeding risk schemata developed for the prediction of the hemorrhagic risk.

CONCLUSIONS

Biomarkers were introduced in clinical practice in order to better estimate the potential risk of haemorrhage in these patients and increase the prognostic impact of clinical risk scores. In the last years this concept is gaining significant importance.

Bleeding risk assessment and management in atrial fibrillation patients

In this executive summary of a Consensus Document from the European Heart Rhythm Association, endorsed by the European Society of Cardiology Working Group on Thrombosis, we comprehensively review the published evidence and propose a consensus on bleeding risk assessments in atrial fibrillation (AF) patients. The main aim of the document was to summarise ‘best practice’ in dealing with bleeding risk in AF patients when approaching antithrombotic therapy, by addressing the epidemiology and size of the problem, and review established bleeding risk factors. We also summarise definitions of bleeding in the published literature. Patient values and preferences balancing the risk of bleeding against thromboembolism as well as the prognostic implications of bleeding are reviewed. We also provide an overview of published bleeding risk stratification and bleeding risk schema. Brief discussion of special situations (e.g. periablation, peri-devices such as implantable cardioverter defibrillators [ICD] or pacemakers, presentation with acute coronary syndromes and/or requiring percutanous coronary interventions/stents and bridging therapy) is made, as well as a discussion of the prevention of bleeds and managing bleeding complications. Finally, this document puts forwards consensus statements that may help to define evidence gaps and assist in everyday clinical practice.

A new algorithm to predict warfarin dose from polymorphisms of CYP4F2, CYP2C9 and VKORC1 and clinical variables: Derivation in Han Chinese patients with non valvular atrial fibrillation

Few pharmacogenomic dosing regimens of warfarin have been developed for Chinese patients with non valvular atrial fibrillation (NVAF). The objective of this study was to develop a new algorithm by polymorphisms of CYP2C9, VKORC1 and CYP4F2 to predict the daily stable dose of warfarin in Chinese patients with NVAF. A total of 325 Chinese NVAF patients on stable dose of warfarin with a target international normalised ratio of 1.5 to 3.0 were recruited and divided randomly into two cohorts. CYP2C9*3, VKORC1 –1639, VKORC1 1173 and CYP4F2 were detected by ligase detection reaction method. The new algorithm was developed with multivariate linear regression in cohort 1 (260 patients) and assessed with Pearson Correlation Analysis (PCA) in cohort 2 (65 patients). From 260 enrolled patients, the model (R2 = 51.7%) was developed as: Dose = 3.47 − 0.022 (AGE) + 0.017 (WT) + 0.189 (PTE) − 0.283 (β-blocker) − 0.471 (AMIO) − 0.586 (CYP2C9 *1/*3) − 0.296 (VKORC1 CT) – 0.648 (VKORC1 TT) + 0.219 (CYP4F2 TT). PCA displayed that the algorithm was good (r = 0.658). The residual plots revealed that the predicted doses by the algorithm tend to be overestimated when lower doses were administered to patients and to be underestimated in higher doses. The algorithm developed by us might predict warfarin dose used by Chinese NVAF patients.

Do open label blinded outcome studies of novel anticoagulants versus warfarin have equivalent validity to those carried out under double-blind conditions?

Recent anticoagulants for stroke prevention in AF have been tested in active comparator controlled studies versus warfarin using two designs: double-blind, double-dummy and prospective randomised, open blinded endpoint (PROBE). The former requires elaborate procedures to maintain blinding, while PROBE does not. Outcomes of double-blind and PROBE designed studies of novel anticoagulants for AF, focusing on warfarin controls, were explored. Major, Phase III warfarin-controlled trials for stroke prevention in AF were identified. Odds ratios (ORs) of key outcomes for active comparators versus VKA and event rates for VKA arms were compared between designs, in context of baseline demographics and inclusion criteria. Identified trials studied five novel anticoagulants in three each of PROBE and double-blind design. For ORs of results across studies and outcomes, there was little pattern differentiating the two designs. Among VKA-control subjects, event rates for the primary outcome (stroke or systemic embolism) in PROBE trials at 1.74 %/year (95% confidence interval: 1.54–1.95) was not significantly different from that in double-blind trials, at 1.88 (1.73–2.03). Among other outcomes, VKA-treated subjects in both trial designs had similar event rates, apart from higher all-cause mortality in ROCKET AF, and lower myocardial infarction rates among the PROBE study patients. Although there are differences in outcome between PROBE and double blind trials, they do not appear to be design-related. The exacting requirements of double-blinding in AF trials may not be necessary.

General mechanisms of coagulation and targets of anticoagulants (Section I)

Contrary to previous models based on plasma, coagulation processes are currently believed to be mostly cell surface-based, including three overlapping phases: initiation, when tissue factor-expressing cells and microparticles are exposed to plasma; amplification, whereby small amounts of thrombin induce platelet activation and aggregation, and promote activation of factors (F)V, FVIII and FXI on platelet surfaces; and propagation, in which the Xase (tenase) and prothrombinase complexes are formed, producing a burst of thrombin and the cleavage of fibrinogen to fibrin. Thrombin exerts a number of additional biological actions, including platelet activation, amplification and self-inhibition of coagulation, clot stabilisation and anti-fibrinolysis, in processes occurring in the proximity of vessel injury, tightly regulated by a series of inhibitory mechanisms. ″Classical″ anticoagulants, including heparin and vitamin K antagonists, typically target multiple coagulation steps. A number of new anticoagulants, already developed or under development, target specific steps in the process, inhibiting a single coagulation factor or mimicking natural coagulation inhibitors.

Stroke Prevention in Atrial Fibrillation: Focus on Latin America

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with an estimated prevalence of 1-2% in North America and Europe. The increased prevalence of AF in Latin America is associated with an ageing general population, along with poor control of key risk factors, including hypertension. As a result, stroke prevalence and associated mortality have increased dramatically in the region. Therefore, the need for effective anticoagulation strategies in Latin America is clear. The aim of this review is to provide a contemporary overview of anticoagulants for stroke prevention. The use of vitamin K antagonists (VKAs, eg, warfarin) and aspirin in the prevention of stroke in patients with AF in Latin America remains common, although around one fifth of all AF patients receive no anticoagulation. Warfarin use is complicated by a lack of access to effective monitoring services coupled with an unpredictable pharmacokinetic profile. The overuse of aspirin is associated with significant bleeding risks and reduced efficacy for stroke prevention in this patient group. The non-VKA oral anticoagulants (NOACbs) represent a potential means of overcoming many limitations associated with VKA and aspirin use, including a reduction in the need for monitoring and a reduced risk of hemorrhagic events. The ultimate decision of which anticoagulant drug to utilize in AF patients depends on a multitude of factors. More research is needed to appreciate the impact of these factors in the Latin American population and thereby reduce the burden of AF-associated stroke in this region.

Contemporary measures to reduce the risk of embolic events in patients with atrial fibrillation

Atrial fibrillation is a common arrhythmia with significant risk of embolic events. Patients with atrial fibrillation should undergo a careful assessment using validated risk score calculators to estimate the risk of embolic events and the risk of bleeding. Patients deemed to be at a high risk for arterial thromboembolism should be advised to take an oral anticoagulant with a vitamin K antagonist or a target-specific oral anticoagulant unless contraindicated. These agents significantly reduce the risk of embolic events, but at the expense of a higher risk of bleeding. Antiplatelet agents do not confer the same degree of protection and their use should limited. When antithrombotic treatment is contraindicated, novel approaches such as left atrial appendage occlusion should be considered.

Stroke and Bleeding Risk Associated With Antithrombotic Therapy for Patients With Nonvalvular Atrial Fibrillation in Clinical Practice

BACKGROUND

The quality of antithrombotic therapy for patients with nonvalvular atrial fibrillation during routine medical care is often suboptimal. Evidence linking stroke and bleeding risk with antithrombotic treatment is limited. The purpose of this study was to evaluate the associations between antithrombotic treatment episodes and outcomes.

METHODS AND RESULTS

A retrospective longitudinal observational cohort study was conducted using patients newly diagnosed with nonvalvular atrial fibrillation with 1 or more stroke risk factors (CHADS2 ≥1) in Kaiser Permanente Southern California between January 1, 2006 and December 31, 2011. A total of 1782 stroke and systemic embolism (SE) and 3528 major bleed events were identified from 23 297 patients during the 60 021 person-years of follow-up. The lowest stroke/SE rates and major bleed rates were observed in warfarin time in therapeutic range (TTR) ≥55% episodes (stroke/SE: 0.87 [0.71 to 1.04]; major bleed: 4.91 [4.53 to 5.28] per 100 person-years), which was similar to the bleed rate in aspirin episodes (4.95 [4.58 to 5.32] per 100 person-years). The warfarin TTR ≥55% episodes were associated with a 77% lower risk of stroke/SE (relative risk=0.23 [0.18 to 0.28]) compared to never on therapy; and the warfarin TTR <55% and on-aspirin episodes were associated with a 20% lower and with a 26% lower risk of stroke/SE compared to never on therapy, respectively. The warfarin TTR <55% episodes were associated with nearly double the risk of a major bleed compared to never on therapy (relative risk=1.93 [1.74 to 2.14]).

CONCLUSIONS

Continuation of antithrombotic therapy as well as maintaining an adequate level of TTR is beneficial to prevent strokes while minimizing bleeding events.

Choosing the right drug to fit the patient when selecting oral anticoagulation for stroke prevention in atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide and is a growing health problem that is associated with a significantly increased risk of stroke and thromboembolism. Oral anticoagulant (OAC) therapy reduces the risk of stroke and all-cause mortality in patients with AF. OAC therapy is commonly given as a well-controlled vitamin K antagonist (VKA; e.g. warfarin) and can reduce the risk of stroke in AF patients by almost two-thirds. However, the widespread use of VKAs has been hampered by the unpredictable pharmacokinetic and pharmacodynamic properties of the drugs and justifiable concerns about the consequent risk of haemorrhage. The non-VKA OACs (NOACs) have revolutionized thromboprophylaxis in AF by providing therapeutic options with predictable pharmacodynamic and pharmacokinetic properties that are as efficacious as warfarin in the prevention of stroke and thromboembolism but are more convenient to use. In this review, we provide a patient-centred framework to assist clinicians in recommending the right OAC therapy to fit the individual patient with AF, including methods for stratifying the risk of stroke and haemorrhage and the chances of achieving tight control of VKA anticoagulation, and we discuss the properties of the NOACs that favour their use in particular patient cohorts.

Untreated atrial fibrillation in the United Kingdom: Understanding the barriers and treatment options

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major preventable cause of stroke and hospitalization. Its prevalence is on the rise worldwide and experts believe it will continue to rise for the foreseeable future, due to the ageing population and increased survival from conditions associated with AF. Despite the fact that oral anticoagulation is effective in preventing strokes due to AF, there is extensive evidence suggesting this therapy remains underused. Barriers to the prescription of anticoagulation include patients' age per se, comorbidities, inadequate risk stratification, perceived risk of falls and bleeding, and the difficulty in achieving a stable international normalized ratio (INR) on warfarin. Also, asymptomatic patients with AF may not be identified and therefore not be candidates for anticoagulation. Physicians need continued better education on the identification of patients at risk of stroke and management of oral anticoagulation. This article reviews the barriers to anticoagulation in patients with AF in the United Kingdom and considers how those barriers may be overcome.

The Potential Role of Edoxaban in Stroke Prevention Guidelines

With the emergence of edoxaban, the oral factor Xa inhibitors now appear consolidated as the dominant class of novel oral anticoagulants (NOACs) for stroke prevention in non-valvular atrial fibrillation (AF). The oral factor Xa inhibitors do not require an adequate time in therapeutic range to be effective, presenting a potential advantage over the vitamin K antagonists (VKAs). Guidelines are changing to reflect the increased choice of anticoagulants and as clinicians move away from the VKAs towards the relative safety and efficacy of NOACs, they must consider which one offers the best therapy for their patient. The ENGAGE-AF study was the latest phase III trial to report on the safety and efficacy of a new factor Xa inhibitor relative to warfarin. Both edoxaban 60mg once daily, and edoxaban 30mg once daily were found to be non-inferior compared to warfarin for the prevention of ischaemic stroke and systemic embolism, being associated with significantly lower rates of major bleeding, intracranial haemorrhage and cardiovascular death. A two-tiered dosing option may present clinicians with a further element of choice for the individual patient.

Efficacy and safety of apixaban compared with warfarin regarding time within the therapeutic range

Prevention of thromboembolism by lifelong anticoagulation is an important therapeutic goal in patients with atrial fibrillation according to recent guidelines. Major drawback of vitamin K antagonists are their narrow therapeutic range and interactions with other drugs and food. These have significant impact on the pharmacokinetics and pharmacodynamics requiring regular measurements of the international normalized ratio. Efficiency of the anticoagulant therapy depends considerably on time within the therapeutic range of prothrombin international normalized ratio. Time within the therapeutic range represents the percentage of time within the required range of prothrombin international normalized ratio. Prothrombin international normalized ratio outside the therapeutic range increases the risk of thromboembolism or bleeding according to whether it falls below or above the range. New oral anticoagulants do not require routine monitoring of anticoagulation. Their efficacy and safety are shown to be at least as good as or better than those of warfarin. In patients with nonvalvular atrial fibrillation ARISTOTLE study revealed that antithrombotic effect of apixaban compared with warfarin is better and with lower bleeding risk irrespective of the quality of prothrombin international normalized ratio control. Orv. Hetil., 2014, 155(5), 177–181.

Frequency and risk factors for under- and over-treatment in stroke prevention for patients with non-valvular atrial fibrillation in general practice

Objective

To determine adequacy of antithrombotic treatment in patients with non-valvular atrial fibrillation. To determine risk factors for under- and over-treatment.

Design

Retrospective, cross-sectional study of electronic health records from 36 general practitioners in 2008.

Setting

General practice in the Netherlands.

Subjects

Primary care physicians (n = 36) and patients (n = 981) aged 65 years and over.

Main Outcome Measures

Rates of adequate, under and over-treatment, risk factors for under and over-treatment.

Results

Of the 981 included patients with a mean of age 78, 18% received no antithrombotic treatment (under-treatment), 13% received antiplatelet drugs and 69% received oral anticoagulation (OAC). Further, 43% of the included patients were treated adequately, 26% were under-treated, and 31% were over-treated. Patients with a previous ischaemic stroke were at high risk for under-treatment (OR 2.4, CI 1.6–3.5), whereas those with contraindications for OAC were at high risk for over-treatment (OR 37.0, CI 18.1–79.9). Age over 75 (OR 0.2, CI: 0.1–0.3]), diabetes (OR 0.1, CI: 0.1–0.3), heart failure (OR 0.2, CI: 0.1–0.3), hypertension (OR 0.1, CI: 0.1–0.2) and previous ischaemic stroke (OR 0.04, CI: 0.02–0.11) protected against over-treatment.

Conclusions

In general practice, CHADS₂-criteria are being used, but the antithrombotic treatment of patients with atrial fibrillation frequently deviates from guidelines on this topic. Patients with previous stroke are at high risk of not being prescribed OAC. Contraindications for OAC, however, seem to be frequently overlooked.

Improving stroke prevention in patients with atrial fibrillation

Background

Patients with atrial fibrillation (AF) are at increased risk for stroke. Antithrombotic treatment reduces this risk. Antithrombotic treatment consists of either administration of oral anticoagulants (OAC) or the provision of an antiplatelet drug. International guidelines provide advice on the preferred treatment, thereby balancing the risks and benefits of OAC. However, adherence to these guidelines is reported to be as low as 50%. There is paucity in research on why adherence rates are low. Recent studies have shown decision support systems can improve guideline adherence. We investigate the use of a clinical decision support system to improve guideline adherence among general practitioners (GPs) treating patients with AF and study reasons for guideline non-adherence.

Methods/Design

The study is a randomized controlled trial, which is performed among Dutch general practitioners. Initially, GPs in the vicinity of the Academic Medical Center (AMC) in Amsterdam will be included, after which other practices will be recruited. We have developed a novel decision support system that displays a list with pending messages for the on-screen medical record in real time. Messages are generated on a server that evaluates a decision rule based on the atrial fibrillation guideline of the Dutch College of General Practitioners. By interacting with the list, messages can be opened for a description and explanation, or be ignored. GPs are allocated into three groups: 1) control group; 2) intervention group A, in which messages can be ignored without justification; and 3) intervention group B, in which messages can only be ignored with justification.

Our main outcome measure is the between-group difference in the proportion of patients receiving antithrombotic prescriptions in adherence to the Dutch GP guideline for atrial fibrillation. Secondary outcomes are reasons GPs state for deviating from the guideline and the effect on guideline adherence of requiring justification when ignoring a message.

Discussion

This paper describes the protocol for a cluster randomized trial to study the effects of a clinical decision support system in patients with atrial fibrillation. The system is characterized by a non-interruptive presentation and real-time messages that are updated after each relevant action the GP performs.

Trial registration

This trial is registered with the Dutch Trial Register under registration number 3570.

Review of economics and cost-effectiveness analyses of anticoagulant therapy for stroke prevention in atrial fibrillation in the US

OBJECTIVE

To summarize the available evidence on the issues in health economics related to oral anticoagulation for stroke prevention in atrial fibrillation (AF) in the US.

DATA SOURCES

A literature review was performed using PubMed, EMBASE, Cochrane Library, and International Pharmaceutical Abstracts, as well as the websites of professional organizations.

STUDY SELECTION AND DATA EXTRACTION

The search was conducted according to a prespecified protocol, limiting articles to those published in English from 2001 to October 2012 and focused on the economics associated with AF and AF-related stroke in the US. Data from 27 studies were extracted and included in the review.

DATA SYNTHESIS

Strokes in patients with AF are more debilitating and have higher recurrence rates and mortality compared with strokes unrelated to AF. However, data describing the long-term cost of AF-related stroke and stroke subtypes remain limited. The costs of major gastrointestinal (GI) bleeding and intracranial bleeding related to warfarin are significant, whereas the costs of the more frequent minor GI bleeding are relatively low. Overall, the cost-effectiveness of warfarin versus aspirin or no treatment in patients with at least 1 risk factor for stroke is well established. Economic evaluations based on results from randomized controlled clinical trials generally found that new anticoagulants were a cost-effective alternative to warfarin for stroke prevention in AF. However, these cost-effectiveness results are highly sensitive to how well optimal international normalized ratio control is maintained (within target of 2.0-3.0) for warfarin and the time horizon used for analysis. Time in therapeutic range for warfarin in routine clinical practice was lower than in clinical trials, as shown by previous studies.

CONCLUSIONS

This review identified several areas of uncertainty regarding the economic benefit of anticoagulants. The generalizability of cost-effectiveness results of anticoagulant therapy in AF based on clinical trial data must be confirmed by comparative effectiveness research conducted in the real-world setting.

Antithrombotic therapy in atrial fibrillation: aspirin is rarely the right choice

Atrial fibrillation, the commonest cardiac arrhythmia, predisposes to thrombus formation and consequently increases risk of ischaemic stroke. Recent years have seen approval of a number of novel oral anticoagulants. Nevertheless, warfarin and aspirin remain the mainstays of therapy. It is widely appreciated that both these agents increase the likelihood of bleeding: there is a popular conception that this risk is greater with warfarin. In fact, well-managed warfarin therapy (INR 2-3) has little effect on bleeding risk and is twice as effective as aspirin at preventing stroke. Patients with atrial fibrillation and a further risk factor for stroke (CHA2DS2-VASc >0) should therefore either receive warfarin or a novel oral agent. The remainder who are at the very lowest risk of stroke are better not prescribed antithrombotic therapy. For stroke prevention in atrial fibrillation; aspirin is rarely the right choice.

Patients' and health professionals' views and experiences of atrial fibrillation and oral-anticoagulant therapy: a qualitative meta-synthesis

OBJECTIVE

Atrial fibrillation (AF) patients are prescribed oral-anticoagulant (OAC) therapy, often warfarin, to reduce stroke risk. We explored existing qualitative evidence about patients' and health professionals' experiences of OAC therapy.

METHODS

Systematic searches of eight bibliographic databases were conducted. Quality was appraised using the Critical Appraisal Skills Programme tool and data from ten studies were synthesised qualitatively.

RESULTS

Four third-order constructs, emerged from the final step in the analysis process: (1) diagnosing AF and the communication of information, (2) deciding on OAC therapy, (3) challenges revolving around patient issues, and (4) healthcare challenges. Synthesis uncovered perspectives that could not be achieved through individual studies.

CONCLUSION

Physicians' and patients' experiences present a dichotomy of opinion on decision-making, which requires further exploration and changes in practice. Outcomes of workload pressure on both health professionals and patients should be investigated. The need for on-going support and education to patients and physicians is critical to achieve best practice and treatment adherence.

PRACTICE IMPLICATIONS

Such research could encourage health professionals to understand and attend better to the needs and concerns of the patient. Additionally these findings can be used to inform researchers and healthcare providers in developing educational interventions with both patients and health professionals.

Prognosis in patients with atrial fibrillation and CHA2DS2-VASc Score = 0 in a community-based cohort study

OBJECTIVES

Patients with atrial fibrillation (AF) and a CHA(2) DS(2) -VASc score = 0 have a very low risk of stroke and current guidelines even recommend no antithrombotic therapy to these patients. We investigated the rate and risk of adverse events and the impact of antithrombotic management in a community based cohort of AF patients with a CHA(2)DS(2)-VASc score = 0.

METHODS AND RESULTS

Patients with AF seen in our institution between 2000 and 2010 were identified in a database. The adverse outcomes were investigated during follow-up. Among 8,962 patients with AF, 616 (7%) had a congestive heart failure, hypertension, age ≥75 years (doubled), diabetes, stroke/TIA/thromboembolism (doubled), vascular disease (prior myocardial infarction, peripheral artery disease, or aortic plaque), age 65-74 years, sex category (female) (CHA(2)DS(2)-VASc score) = 0. An oral anticoagulant was prescribed in 273 patients (44%), antiplatelet therapy alone in 145 patients (24%), and no antithrombotic treatment in 198 patients (32%). During a follow up of 876 ± 1,135 days (median 244, interquartile range 1,540 days), 38 patients sustained events (10 stroke/thromboembolism, 19 major bleeding, 17 deaths). Among untreated patients, rates of stroke/thromboembolism, major bleeding and mortality were 0.64%, 1.12%, and 1.08% per year. Prescription of oral anticoagulation and/or antiplatelet therapy was not associated with an improved prognosis for stroke/thromboembolism (relative risk [RR] = 0.99, 95% CI 0.25-3.99, P = 0.99), nor improved survival or net clinical benefit (combination of stroke/thromboembolism, bleeding, and death).

CONCLUSION

In a real life cohort study, AF patients with CHA(2)DS(2) VASc score = 0 had a low risk of stroke/thromboembolism that was not significantly different between those taking oral anticoagulation, antiplatelet therapy, or no antithrombotic therapy. This supports current guideline recommendations for no antithrombotic therapy in these "truly low-risk" patients.