Antagonist Oral Anticoagulants Research Articles

Profile of patients diagnosed with acute venous thromboembolism in routine practice according to age and renal function: RE-COVERY DVT/PE study

In randomized clinical trials (RCTs) of nonvitamin K antagonist oral anticoagulants (NOACs) for acute venous thromboembolism (VTE), ~ 12–13% of patients were elderly and ~ 26% had mild-to-moderate renal impairment. Observational studies are not restricted by the selection and treatment criteria of RCTs. In this ancillary analysis of the RE-COVERY DVT/PE global observational study, we aimed to describe patient characteristics, comorbidities, and anticoagulant therapy for subgroups of age (< or ≥ 75 years) and renal impairment (creatinine clearance [CrCl; estimated with Cockcroft–Gault formula] < 30 [severe], 30 to < 50 [moderate], 50 to < 80 [mild], ≥ 80 [normal] mL/min). Of 6095 eligible patients, 25.3% were aged ≥ 75 years; 38.2% (1605/4203 with CrCl values) had mild-to-moderate renal impairment. Comorbidities were more common in older patients (73.9% aged ≥ 75 vs. 58.1% < 75 years) and in those with mild or moderate versus no renal impairment (75.9%, 80.9%, and 59.3%, respectively). At hospital discharge or 14 days after diagnosis (whichever was later), most patients (53.7% and 55.1%, respectively) in both age groups received NOACs; 20.8% and 23.4%, respectively, received vitamin K antagonists, 19.0% and 21.8% parenteral therapy, 2.3% and 3.8% other anticoagulant treatments. Use of NOACs decreased with worsening renal impairment (none 58.5%, moderate 49.6%, severe 25.7%) and, in younger versus older patients with moderate renal impairment (33.1% vs. 56.1%). In routine practice, there are more elderly and renally impaired patients with VTE than represented in RCTs. Decreasing renal function, but not older age, was associated with less NOAC use. Clinical Trial Registration: http://www.clinicaltrials.gov. Unique identifier: NCT02596230.Graphic abstractDecreasing renal function, particularly in the subgroup with CrCl < 30 mL/min, but not older age, was associated with less use of nonvitamin K antagonist oral anticoagulants (NOACs). Nevertheless, more than half of the older patients with moderate renal impairment received a NOAC as their oral anticoagulant.

Reducing the cost of managing patients with atrial fibrillation undergoing percutaneous coronary intervention with stenting

Patients undergoing percutaneous coronary intervention (PCI) have an increased risk of both ischemic events and bleeding complications resulting from antithrombotic therapy. These events are particularly common in patients with a concomitant indication for oral anticoagulation, such as those with atrial fibrillation, and are associated with a substantial healthcare resource burden. Advances in procedural aspects of PCI have led to marked improvements in outcomes and a consequent reduction in the costs resulting from PCI-associated complications. Furthermore, recent randomized clinical trials have investigated the optimal antithrombotic strategy in the specific case of patients with atrial fibrillation undergoing PCI, leading to a shift toward the tailoring of antithrombotic therapy according to the patient’s individual stroke and bleeding risks. Here we review these recent advances, with a particular focus on the improvements in antithrombotic strategies offered by the non-vitamin K antagonist oral anticoagulants.

Efficacy and safety of non-vitamin K antagonist versus vitamin K antagonist oral anticoagulants in the prevention and treatment of thrombotic disease in active cancer patients: a systematic review and meta-analysis of randomized controlled trials

Object We aimed to compare the efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOAC) and vitamin K antagonist (VKA) in the prevention and treatment of thrombotic diseases in patients with active cancer. Methods: To find randomized controlled trials (RCT) in which NOACs were compared VKAs in active cancer, we searched the electronic databases (PubMed, Web of Science and Clinical Trials) up to May 2019 and and languages restricted to Chinese and English. According to the screening strategy, two researchers independently screened and extracted literature, evaluated the quality of literature, the suitability of collected cross study data for analysis, and tested the heterogeneity. The relative risk (RR) and 95% confidence interval (95%CI) of major bleeding, clinically related non-major bleeding, VTE, stroke and all-cause mortality in active cancer patients with VTE, active cancer patients with non-valvular atrial fibrillation (NVAF) was calculated and the results were compared between NOAC with VKA. Results: A total of 9 RCTs were included, including 5 cancers with VTE (5/9) and 4 cancers with NVAF (4/9). A total of 5 867 patients were included. After excluding 1 818 (30.99%) patients with cancer history, 4 049 (68.86%) patients with active cancer were statistically analyzed. Among them, 2 278 (56.26%) received NOAC treatment, 1 771 patients (43.74%) received VKA treatment. The quality of the included documents was high (all scores were>5 points), and the data of each included document could be summarized and analyzed (P>0.05). The heterogeneity of main outcome events was very low (I2 = 0). In VTE patients with active cancer, NOACs were more effective in reducing recurrence of VTE （RR=0.55, 95%CI 0.36 -0.84; P = 0.005) and clinically related non-major bleeding (RR=0.77, 95%CI 0.60 -0.98; P = 0.03) than VKAs. In NVAF patients with active cancer, efficacy of NOACs and VKAs was similar in terms of reducing VTE, stroke, clinically related non-major bleeding, major bleeding and all-cause mortality events (P>0.05). Conclusions: For patients with active cancer accompanied by VTE, NOAC may has more advantages in efficacy and safety compared to VKA in the prevention and treatment of thrombotic diseases.

Factors associated with silent cerebral events during atrial fibrillation ablation in patients on uninterrupted oral anticoagulation.

Silent cerebral events (SCEs) are related to the potential thromboembolic risk in atrial fibrillation (AF) ablation. Periprocedural uninterrupted oral anticoagulation (OAC) reportedly reduced the risk of SCEs, but the incidence still remains. AF patients undergoing catheter ablation were eligible. All patients took non-vitamin K antagonist oral anticoagulants (NOACs; n = 248) or vitamin K antagonist (VKA; n = 37) for periprocedural OAC (>4 weeks) without interruption during the procedure. Brain magnetic resonance imaging was performed within 2 days after the procedure to detect SCEs. Clinical characteristics and procedure-related parameters were compared between patients with and without SCEs. SCEs were detected in 66 patients (23.1%; SCE[+]) but were not detected in 219 patients (SCE[-]). Age was higher in SCE[+] than in SCE[-] (66 ± 10 vs. 62 ± 12 years; p < .05). Persistent AF prevalence, CHADS2 /CHA2 DS2 -VASc scores, serum NT-ProBNP levels, left atrial dimension (LAD), and spontaneous echo contrast prevalence in transesophageal echocardiography significantly increased in SCE[+] versus SCE[-]. SCE[+] had lower baseline activated clotting time (ACT) before heparin injection and longer time to reach optimal ACT (>300 s) than SCE[-] (146 ± 27 vs. 156 ± 29 s and 44 ± 30 vs. 35 ± 25 min; p < .05, respectively). In multivariate analysis, age, LAD, baseline ACT, and time to reach the optimal ACT were predictors for SCEs. The average values of the ACT parameters were significantly different among NOACs/VKA. Age, LAD, and intraprocedural ACT kinetics significantly affect SCEs during AF ablation. Different anticoagulants have different impacts on ACT during the procedure, which should be considered when estimating the risk of SCEs.

Factors influencing adherence to non-vitamin K antagonist oral anticoagulants in the early period after atrial fibrillation catheter ablation in China.

Factors influencing adherence to non-vitamin K antagonist oral anticoagulants in the early period after atrial fibrillation catheter ablation in China.

Appropriate Dosing Regimens of Non-Vitamin K Antagonist Oral Anticoagulants for Treatment of Patients With Non-Valvular Atrial Fibrillation: An Evidence-Based Consideration.

Patients with non-valvular atrial fibrillation (NVAF) exhibit a high risk of stroke, which is associated with high mortality. Thus, stroke prevention is crucial for the overall management of NVAF. Two categories of drugs, vitamin K antagonist warfarin and non-vitamin K antagonist oral anticoagulants (NOACs), are clinically used to prevent NVAF-related stroke. In some circumstances, NOACs are superior to warfarin. However, NOACs selection for NVAF patients is affected by many factors, including individual patient characteristics, comorbidities, risk factors, or laboratory variables. This article summarizes the discrepancy in NOACs management with emphasis on the dosing regimens and influencing factors, such as stroke risk, age, body weight, renal function, gastrointestinal bleeding (GIB) risk, and combination of antiplatelet therapy, in order to identify individual groups with particular clinical characteristics who may obtain more benefit from a certain dosing regimen of NOACs. Determination of a particular subset of patient populations for the appropriate dose regimen of NOACs will help to achieve desired clinical outcomes. Furthermore, to compensate clinical evidence, we should place more emphasis on the findings of current clinical trials and supplement real-world data.

Patients Taking Direct Oral Anticoagulants (DOAC) Undergoing Oral Surgery: A Review of the Literature and a Proposal of a Peri-Operative Management Protocol.

Patients on anticoagulant therapy for the prevention of cardiovascular accidents present an increased risk of bleeding following dental and oral surgery. Four recently introduced non-vitamin K antagonist oral anticoagulants, namely dabigatran etexilate (direct thrombin inhibitor), rivaroxaban, apixaban, and edoxaban (Xa factor direct inhibitor), are widely spreading for convenience of use compared to the older drug class. Dental management of patients taking these drugs has substantial differences compared to patients on vitamin K antagonist therapy. Anticoagulation is not assessed directly through a hematological test, but indirectly by renal function. The interventions must be scheduled at the time of minimum blood concentration of the drug. Bleeding can occur even after several days following the surgery. The interaction with drugs administered for dental care must be carefully evaluated. The peri-operative diet can influence the risk of bleeding. Local measures favoring coagulation must be adopted. The interventions with higher risk must be divided into multiple less invasive interventions. Although antidotes exist for these drugs, their use does not seem necessary for dental interventions that have been planned optimally. Furthermore, in this review of the literature a decision protocol is proposed for the evaluation of the suspension of the anticoagulant drug before oral surgery. Cessation of any anticoagulant should only be made in consultation with the patient’s general practitioner/cardiologist, who will weigh up the risk of bleeding from the proposed procedure with the risk of thrombosis/stroke in each individual patient.

Temporal trends of atrial fibrillation and/or rheumatic heart disease-related ischemic stroke, and anticoagulant use in Chinese population: An 8-year study

Background and PurposeUnderuse of anticoagulants in ischemic stroke patients with atrial fibrillation (AF) and/or rheumatic heart disease (RHD) is a global concern, especially in China. However, the extent to which anticoagulants are underused in AF and/or RHD-related ischemic stroke in China has not been well characterized. We aimed to explore the temporal trends of AF and/or RHD-related ischemic stroke patients, anticoagulation use and factors related to suboptimal use of anticoagulants in a Chinese population. MethodsAcute ischemic stroke patients admitted to department of neurology, West China hospital, Sichuan university were included from January 1st 2010 to December 31st 2017. Temporal trends of AF and RHD related ischemic strokes were compared over 2 year epochs (2010–2011, 2012–2013, 2014–2015 and 2016–2017). Multivariable logistic regression models were performed to evaluate the variables associated with non-anticoagulants at discharge. ResultsOf 4357 acute ischemic stroke patients (≤7 days after onset) included between 2010 and 2017, 823(18.9%) were AF and/or RHD-related. Over the 8 years, the proportion of RHD-ischemic stroke decreased significantly from 7.8% in 2010–2011 to 4.5% in 2016–2017, whereas no reduction in AF-ischemic stroke was observed. There was an increase in the proportion of AF and/or RHD patients who were prescribed anticoagulants at discharge (from 26.4% to 45.1%, P for trend<0.001), while the proportion given antiplatelet therapy decreased with time (from 56.0% to 30.0%, P for trend<0.001). The use of non-vitamin K antagonist oral anticoagulants (NOAC) use at discharge remained low during the study period (2.1%).Older age (per 5 years increase, OR 1.91, 95% CI 1.28–2.86), higher NIHSS score on admission(OR 1.08, 95% CI 1.05–1.11), the presence of non-symptomatic hemorrhagic transformation(OR 2.54, 95% CI 1.67–3.94) and symptomatic hemorrhagic transformation(OR 3.04, 95% CI 1.14–9.73) were independently associated with non-anticoagulant use at discharge. However, patients with a prior diagnosis of AF/RHD and anticoagulation before admission were more likely to receive anticoagulants at discharge. ConclusionsIn an ischemic stroke population in China we found an increasing but still low use of anticoagulation. Further research is required on how to improve anticoagulation use at discharge in ischemic stroke patients, including access to NOAC's.

Non-vitamin K antagonist oral anticoagulants in very elderly east Asians with atrial fibrillation: A nationwide population-based study

The evidence of effectiveness and safety of the non-vitamin K antagonist oral anticoagulants (NOACs) among elderly East Asians is limited. We aimed to describe the effectiveness and safety outcomes associated with NOACs and warfarin among elderly Koreans aged ≥80 years. Using the Korean Health Insurance Review and Assessment service database, patients with atrial fibrillation (AF) who were naïve to index oral anticoagulant between 2015 and 2017 were included in this study (20,573 for NOACs and 4086 for warfarin). Two treatment groups were balanced using the inverse probability of treatment weighting (IPTW) method. The clinical outcomes including ischemic stroke, major bleeding including intracranial hemorrhage (ICH) and gastrointestinal bleeding (GIB), and a composite of these outcomes were evaluated. Compared to warfarin, NOACs were associated with lower risks of ischemic stroke (hazard ratio 0.74 [95% confidence interval 0.62-0.89]), and composite outcome (0.78 [0.69-0.90]). NOACs showed nonsignificant trends towards to lower risks of GIB and major bleeding than warfarin. The risk of ICH of NOAC group was comparable with the warfarin group. Among NOACs, apixaban and edoxaban showed better composite outcomes than warfarin. Among the clinical outcomes, only ischemic stroke and the composite outcome had a significant interaction with age subgroups (80-89 years and ≥90 years, P-for-interaction = .097 and .040, respectively). NOACs were associated with lower risks of ischemic stroke and the composite outcome (ischemic stroke and major bleeding) compared to warfarin in elderly East Asians. Physicians should be more confident in prescribing NOACs to elderly East Asians with AF.

Safety and efficacy of non-vitamin K antagonist oral anticoagulants for prevention of thromboembolism in adults with systemic right ventricle: Results from the NOTE international registry

BackgroundPatients with systemic right ventricle (sRV), including transposition of great arteries (TGA) after atrial switch procedure and congenitally corrected transposition of great arteries (ccTGA), may require anticoagulation for thromboembolism (TE) prevention. In the absence of data on non-vitamin K antagonist oral anticoagulants (NOACs), vitamin K antagonists (VKAs) remain the agent of choice. We investigated the safety, efficacy and feasibility of NOACs treatment in adults with sRV in a worldwide study. MethodsThis is an international multicentre prospective study, using data from the NOTE registry on adults with sRV taking NOACs between 2014 and 2019. The primary endpoints were TE and major bleeding (MB). The secondary endpoint was minor bleeding. ResultsA total of 76 patients (42.5 ± 10.0 years, 76% male) with sRV (74% TGA, 26% ccTGA) on NOACs were included in the study. During a median follow-up of 2.5 years (IQR1.5–3.9), TE events occurred in 3 patients (4%), while no MB episodes were reported. Minor bleeding occurred in 9 patients (12%). NOAC treatment cessation rate was 1.4% (95%CI:0.3–4%) during the first year of follow-up. All the patients with TE events had a CHA2DS2-VASc score ≥ 2 and impaired sRV systolic function at baseline. The total incidence of major events during follow-up was significantly lower compared to historical use of VKAs or aspirin before study inclusion (1.4% (95%CI:0.29–4%) vs 6,9% (95%CI:2.5–15.2%); p = .01). ConclusionsIn this prospective study, NOACs appear to be well-tolerated, with excellent efficacy and safety at mid-term in patients with sRV.

Efficacy and safety of non-vitamin K anticoagulants and warfarin in patients with atrial fibrillation and heart failure: A network meta-analysis

BackgroundTo recommend the proper anticoagulant drug and its dose for patients with atrial fibrillation (AF) and heart failure (HF), we conducted a network meta-analysis (NMA) to make the comparisons among non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin with regard to efficacy (stroke or systemic embolism) and safety (major bleeding). MethodsWe searched PubMed, EMBASE, Web of Science and Cochrane Library with the items: “dabigatran, edoxaban, apixaban, rivaroxaban, warfarin, atrial fibrillation and heart failure” through April 14, 2020, focusing on the RCTs comparing the effect of NOACs to warfarin in patients with AF and HF. The NMA was performed based on R (version3.5.1) recalling JAGS (version4.3.0) with gemtc package. Moreover, NetMetaXL (version1.6.1) and winBUGS (version1.4.3) were employed to obtain the cumulative ranking curve area (SUCRA) of the anticoagulants. ResultThere was a high probability that dabigatran150 (SUCRA 0.82) ranked the first for the most effective drug, followed by apixaban (SUCRA 0.81), edoxaban60 (SUCRA 0.57) and rivaroxaban (SUCRA 0.52). However, with respect to safety for preventing major bleeding, edoxaban30 (SUCRA 0.99) ranked as the safest drug, followed by apixaban (SUCRA 0.71), edoxaban 60 (SUCRA 0.59) and dabigatran150 (SUCRA 0.55). ConclusionApixaban, edoxaban60 and dabigatran150 were more likely to become the choice for preventing stroke or systemic embolism and major bleeding in patients with AF and HF. Nevertheless, more trials need to be performed to focus on the effect of NOACs on the efficacy outcome due to the sparse data. In addition, caution should be excised over selecting the NOAC and its dose on account of the lacking head-to-head comparisons.

Predictors of Oral Anticoagulants Utilization in Patients with Atrial Fibrillation

Introduction: Atrial fibrillation (AF) is the most common sustained cardiac rhythm disturbance, increasing in prevalence with age. It is often associated with structural heart disease, although a substantial proportion of patients with AF have no detectable heart disease. Hemodynamic impairment and thromboembolic events related to AF result in significant morbidity, mortality, and cost. Several factors are associated with the prescription of oral anticoagulants. This review predicts the overall factors that are associated with oral anticoagulant utilization in patients with AF.&#x0D; Methods: Literatures that analyze the predictors of oral anticoagulant utilization in atrial fibrillation were searched using PubMed and Google Scholar published in journals from 2003 to 2019. Eligibility, data extraction and quality assessment were followed by a narrative synthesis of data. An extensive search of recent literature was performed.&#x0D; Results: Older age, comorbidities like hypertension, diabetes, heart failure, coronary artery disease, peripheral artery disease, moderate to severe kidney disease, polypharmacy, higher stroke and bleeding risk, history of smoking and alcohol or substance abuse, and lower cost are predictors of warfarin utilization. Similarly, younger age, better kidney function with creatinine clearance at least 30 mL/min, no or lower risk of stroke and hemorrhage, no polypharmacy, less comorbidities, prescriptions by neurologists and cardiologist, people residing in countries with lower poverty rates, and high cost are potential predictors of non-vitamin K antagonist oral anticoagulants utilization.&#x0D; Conclusion: Our study suggests that knowing the predictors for anticoagulation utilization can improve medication appropriateness in arterial fibrillation patients.

Use of Oral Anticoagulation and Diabetes Do Not Inhibit the Angiogenic Potential of Hypoxia Preconditioned Blood-Derived Secretomes.

Patients suffering from tissue ischemia, who would greatly benefit from angiogenesis-promoting therapies such as hypoxia preconditioned blood-derived secretomes commonly receive oral anticoagulation (OA) and/or have diabetes mellitus (DM). In this study, we investigated the effect of OA administration on the in vitro angiogenic potential of hypoxia preconditioned plasma (HPP) and serum (HPS), prepared from nondiabetic/diabetic subjects who did not receive OA (n = 5) or were treated with acetylsalicylic acid (ASA, n = 8), ASA + clopidogrel (n = 10), or nonvitamin K antagonist oral anticoagulants (n = 7) for longer than six months. The effect of DM was differentially assessed by comparing HPP/HPS obtained from nondiabetic (n = 8) and diabetic (n = 16) subjects who had not received OA in the past six months. The concentration of key proangiogenic (vascular endothelial growth factor or VEGF) and antiangiogenic (thrombospondin-1 or TSP-1 and platelet factor-4 or PF-4) protein factors in HPP/HPS was analyzed via ELISA, while their ability to induce microvessel formations was examined in endothelial cell cultures. We found that OA use significantly reduced VEGF levels in HPP, but not HPS, compared to non-OA controls. While HPP and HPS TSP-1 levels remained largely unchanged as a result of OA usage, HPS PF-4 levels were significantly reduced in samples obtained from OA-treated subjects. Neither OA administration nor DM appeared to significantly reduce the ability of HPP or HPS to induce microvessel formations in vitro. These findings indicate that OA administration does not limit the angiogenic potential of hypoxia preconditioned blood-derived secretomes, and therefore, it does not prohibit the application of these therapies for supporting tissue vascularization and wound healing in healthy or diabetic subjects.

Inclusion in the World Health Organization Model List of Essential Medicines of Non-Vitamin K Anticoagulants for Treatment of Non-Valvular Atrial Fibrillation: A Step Towards Reducing the Burden of Cardiovascular Morbidity and Mortality.

Non-vitamin K antagonist oral anticoagulants (NOACs) represent a paradigm shift in the treatment of non-valvular atrial fibrillation (AF) with major practice guidelines around the world recommending NOACs over vitamin K antagonist oral anticoagulants for initial treatment of AF for stroke prevention. Here we describe the evidence collated and the process followed for the successful inclusion of NOACs into the 21st WHO Model List of Essential Medicines (EML).Individual NOACs have been reported to be non-inferior or superior to warfarin in preventing stroke and systemic embolism in eligible AF patients with a reduction in the risk of stroke and systemic embolism and a lower risk of major bleeding in patients with non-valvular AF compared with warfarin in both RCTs and real-world data.The successful inclusion of NOACs in the WHO EML is an important step forward in the global fight against cardiovascular morbidity and mortality, especially in low- and middle-income countries, where the burden of disease is high and limited access to diagnosis and treatment translates into a higher burden of morbidity, mortality, and economic costs.

Safety and Efficacy of Double Antithrombotic Therapy With Non-Vitamin K Antagonist Oral Anticoagulants in Patients With Atrial Fibrillation Undergoing Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis.

BackgroundThe optimal antithrombotic therapy for patients with atrial fibrillation undergoing percutaneous coronary intervention is a topic of debate. We aimed at defining the efficacy and safety of double antithrombotic therapy with single antiplatelet therapy (SAPT) plus a non–vitamin K antagonist oral anticoagulant (NOAC) against triple antithrombotic therapy with dual antiplatelet therapy (DAPT) added to a vitamin K antagonist (VKA), illustrating the pooled cumulative distribution of events, the ranking of different NOACs tested in NOAC+SAPT combination strategies, and the state of the current evidence in the field.Methods and ResultsRandomized controlled trials meeting the inclusion criteria were identified. The primary efficacy end point was the composite of trial‐defined major adverse cardiac events. The primary safety end point was clinically significant bleeding. Secondary end points were the components of primary end points. Trial‐level pairwise and Bayesian network meta‐analyses, reconstructed Kaplan–Meier analyses, and trial sequential analysis were performed. Four randomized controlled trials (10 969 patients) were included. No differences were found in terms of major adverse cardiac events (hazard ratio [HR], 1.07; 95% CI, 0.94–1.22), and the NOAC+SAPT strategy showed a lower rate of clinically significant bleeding compared with VKA + DAPT (HR, 0.56; 95% CI, 0.39–0.80). These results were consistent in reconstructed Kaplan–Meier analyses. In the Bayesian network meta‐analysis, different NOACs displayed diverse risk–benefit profiles. Trial sequential analyses suggest that the evidence for the similarity in major adverse cardiac events compared with VKA + DAPT and the bleeding risk reduction observed with NOAC+SAPT is likely to be conclusive.ConclusionsNOAC+SAPT does not increase the risk of major adverse cardiac events and reduces the risk of bleeding compared with VKA + DAPT in AF patients undergoing percutaneous coronary intervention. Various NOACs may have different risk–benefit profiles in combination strategies.RegistrationURL: https://www.crd.york.ac.uk/prospero/; Unique identifier: CRD42020151089.

Use of real-world evidence in meta-analyses and cost-effectiveness models

Real-world evidence (RWE) provides external validity, supplementing and enhancing the randomized controlled trial data with valuable information on patient behaviors and outcomes, turning efficacy and safety results into real-world effectiveness and risks, but the use of RWE is associated with challenges. The objectives of this communication were to (1) summarize all guidance on how to conduct an RWE meta-analysis (MA) and how to develop an RWE cost-effectiveness model, (2) to describe our experience, challenges faced and solutions identified, (3) to provide recommendations on how to conduct such analyses. No formal guidelines on how to conduct an RWE MA or to develop an RWE cost-effectiveness model were identified. Using the context of non-vitamin K antagonist oral anticoagulants in stroke prevention in atrial fibrillation, we conducted an RWE MA, after having identified sources of uncertainty. We then implemented the results in an RWE cost-effectiveness model, defined as a model where all inputs come from RWE, including all parameters related to treatment effect. Based on challenges faced, our first recommendation relates to the necessity of conducting sensitivity analyses, either based on clinical or methodological considerations. Our second recommendation is the need for extensive collaboration with a wide range of experts, during the development of the analyses protocols, the implementation of the analyses and the interpretation of the results. RWE may address a number of gaps related to the treatment effect, and RWE economic evaluations for the treatment effect can provide extremely valuable insights into real-world economic value of interventions. As the increased recognition of the value of RWE could influence health technology assessment decision, and current practices, this communication supports the urgent need of more formal guidelines.

Inappropriate dose of nonvitamin-K antagonist oral anticoagulants: prevalence and impact on clinical outcome in patients with nonvalvular atrial fibrillation.

Limited real-world data are available regarding the outcome of patients treated with inappropriate dose of nonvitamin-K antagonist oral anticoagulants (NOACs). To assess the prevalence and factors associated with inappropriate dose prescription of NOACs and to evaluate adverse events that come from this inappropriate prescription. Single-center multidisciplinary registry including nonvalvular atrial fibrillation patients treated with NOACs. Based on guidelines criteria for dose reduction, two subcohorts were defined as treated with appropriate or inappropriate NOACs dose. Primary efficacy endpoint was 2-year rate of thromboembolic events. Primary safety endpoint was 2-year rate of major bleeding. Event-free survival curves among groups were compared using Cox-Mantel test. A total of 760 nonvalvular atrial fibrillation patients were included; 32% patients were treated with dabigatran, 34% with apixaban, 24% with rivaroxaban and 10% with edoxaban. An inappropriate dose was prescribed in 96 patients (12.6%), and in most cases (68%) it was too low. Rivaroxaban (15%) and apixaban (18.5%) were the most frequently prescribed with an inappropriate dose. Patients treated with an inappropriate dose were elderly people, with low-creatinine clearance value, who had experienced previous bleeding and with a high CHADS2 VASc score. In 2 years, a trend for higher numbers of thromboembolic events (5.2 vs. 3.3%, P = 0.348) and less major bleeding (2.1 vs. 4.2%, P = 0.316) has been observed in patients with inappropriate NOACs prescriptions. Nearly 13% of patients were treated with an inappropriate dose of NOACs, in this single-center study. A trend for higher numbers of thromboembolic events was observed in these patients. The results should be considered as hypothesis generating.

Underuse of oral anticoagulants in privately insured patients with atrial fibrillation: A population being targeted by the IMplementation of a randomized controlled trial to imProve treatment with oral AntiCoagulanTs in patients with Atrial Fibrillation (IMPACT-AFib)

Many studies showing underuse of oral anticoagulants (OACs) in patients with atrial fibrillation (AF) predated the advent of the non-vitamin K antagonist OACs. We retrospectively examined use of OACs in a large commercially insured population. Administrative claims data from 4 research partners participating in FDA-Catalyst, a program of the Sentinel Initiative, were queried in September 2017. Patients were included if they were ≥30 years old with ≥365 days of medical/pharmacy coverage, and had ≥2 diagnosis codes for AF, a CHA2DS2-VASc score ≥2, absence of contraindications to OAC use, and no evidence of OAC use in the 365 days before the index AF diagnosis. The main outcome measures of the current analysis were rates of OAC use in the prior 12 months of cohort identification and factors associated with non-use. A total of 197,806 AF patients met the eligibility criteria prior to assessment of OAC treatment. Of these, 179,580 (91%) patients were ≥65 years old and 73,286 (37%) patients were ≥80 years old. Half of the patients (98,903) were randomized to the early intervention arm in the IMPACT-AFib trial and constitute the cohort for this analysis. Of these, 32,295 (33%) had no evidence of OAC use in the prior 12 months. Compared with patients with evidence of OAC use in the prior 12 months, patients without OAC use were more likely to be ≥80 years old, women, and have a history of anemia (51% vs 47%) and less likely to have diabetes (41% vs 44%), history of stroke or TIA (15% vs 19%), and history of heart failure (39% vs 48%). Despite a high risk of stroke, one-third of privately insured patients with AF and no obvious contraindications to an OAC were not treated with an OAC. There is an unmet need for evidence-based interventions that could lead to greater use of OACs in patients with AF at risk for stroke.

Clopidogrel response in patients receiving the nonvitamin K antagonist oral anticoagulants apixaban and rivaroxaban.

Clopidogrel response in patients receiving the nonvitamin K antagonist oral anticoagulants apixaban and rivaroxaban.

Off-label dosing of non–vitamin K antagonist oral anticoagulants and clinical outcomes in Asian patients with atrial fibrillation

Off-label dosing non-vitamin K antagonist oral anticoagulants (NOACs) are commonly prescribed for Asian patients with atrial fibrillation (AF). The purpose of this study was to investigate the associations between inappropriate dosing of NOACs and clinical outcomes. We used medical data from a multicenter health care system in Taiwan, which included 2068, 5135, 2589, 1483, and 2342 AF patients taking dabigatran, rivaroxaban, apixaban, edoxaban, and warfarin, respectively. The risks of ischemic stroke/systemic embolism (IS/SE) and major bleeding in patients treated with underdosing or overdosing NOACs were compared to those of on-label dosing NOACs and warfarin. About 27% and 5% of AF patients were treated with underdosing and overdosing NOACs, respectively. Compared to on-label dosing, underdosing NOACs were associated with a significantly higher risk of IS/SE (adjusted hazard ratio [aHR] 1.59; 95% confidence interval [CI] 1.25-2.02; P <.001), whereas overdosing NOACs were associated with a significantly higher risk of major bleeding (aHR 2.01; 95% CI 1.13-3.56; P = .017). Compared to warfarin, the 4 on-label dosing NOACs were associated with a comparable risk of IS/SE and a significantly lower risk of major bleeding, whereas underdosing NOACs were associated with a higher risk of IS/SE (aHR 1.46; P = .012). About 3 in 10 Asian AF patients were treated with off-label dosing NOACs in daily practice. Compared to on-label dosing, underdosing was associated with a higher risk of IS/SE, whereas overdosing was associated with a higher risk of major bleeding. Thus, even for Asian AF patients at higher risk for bleeding, NOACs still should be prescribed at the dosing based on clinical trial criteria and guideline recommendations.