Cost-effectiveness analysis of dabigatran versus rivaroxaban for stroke prevention in patients with non-valvular atrial fibrillation using real-world evidence in elderly US Medicare beneficiaries

Objective: Dabigatran and rivaroxaban have been approved by the US FDA to reduce the risk of stroke and systemic embolism in non-valvular atrial fibrillation (NVAF) patients. Newly published real-world evidence based on the US population found that elderly Medicare patients with NVAF treated with rivaroxaban experienced statistically significant increases in intracranial hemorrhage (ICH) and major extracranial bleeding, and statistically nonsignificant decreases in thromboembolic stroke and acute myocardial infarction (AMI) compared with dabigatran. This study assessed the cost-effectiveness of dabigatran vs. rivaroxaban for the treatment of US Medicare NVAF patients.

Methods: A previously published Markov model was adapted to compare dabigatran and rivaroxaban. The model considered thromboembolic stroke, bleeding events, and AMI based on the published real-world event risks. Model outputs included clinical event rates, costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs).

Results: Dabigatran patients experienced fewer ICH and major extracranial bleeding events than rivaroxaban patients, but more stroke and AMI events. Dabigatran was found to yield lower costs and higher QALYs than rivaroxaban, with incremental costs of ?$3534 and incremental QALYs of 0.004. Results remained consistent in sensitivity analyses, with a positive net monetary benefit (willingness-to-pay thresholds of $50,000 and $100,000 per QALY) for dabigatran over rivaroxaban for all model inputs tested.

Conclusions: In this study using US Medicare real-world data, dabigatran was found to dominate rivaroxaban. The analyses were limited by the short follow-up period of the real-world data and results may not be generalizable to other patient populations.     

Safety and efficacy of non-vitamin K oral anticoagulants in non-valvular atrial fibrillation: a Bayesian meta-analysis approach

Introduction: Choosing between different non-vitamin K antagonist oral anticoagulants (NOACs) in non-valvular atrial fibrillation (NVAF) is difficult due to the absence of head to head comparative studies. We performed a Bayesian meta-analysis to explore similarities and differences between different NOACs and to rank treatments overall for safety and efficacy outcomes.

Areas covered: Through a systematic literature search we identified randomized controlled Phase III trials of dabigatran, rivaroxaban, apixaban, and edoxaban versus adjusted-dose warfarin in patients with NVAF.

Expert opinion: Warfarin ranked worst for all-cause mortality and intracranial bleedings and had a nil probability of ranking first for any outcome. The risk of major bleeding versus warfarin was lower with apixaban, dabigatran 110 mg, and both doses of edoxaban. All agents reduced the risk of intracranial bleeding versus warfarin. Edoxaban 30 mg was the best among the treatments being compared for major and gastrointestinal bleeding. Dabigatran 150 mg was the best for stroke and systemic embolism. This study suggests that NOACs are generally preferable to warfarin in patients with NVAF. However, safety and efficacy differences do exist among NOACs, which might drive their use in specific subsets of AF patients, allowing prescribers to tailor treatment to distinct patient profiles.     

Quality of oral anticoagulation control in Chinese patients with non-valvular atrial fibrillation: a prospective controlled study

Abstract

Objective

The sex, age, medical history, treatment, tobacco use, race risk (SAMe-TT₂R₂) Score; the sex, age, medical history, treatment, tobacco use, genotype combination (SAMe-TT₂G₂) Score; and the so-called modified SAMe-TT₂R₂ scores have been proposed to predict the anticoagulation quality for patients with non-valvular atrial fibrillation (NVAF). The data from a prospective controlled study is used to validate the SAMe-TT₂R₂ and SAMe-TT₂G₂ scores in Chinese NVAF patients treated with warfarin and to evaluate the association of factors with time in therapeutic range (TTR) to predict the quality of oral anticoagulation control.     

Real-life behaviour of direct oral anticoagulants in a Spanish cohort with non-valvular atrial fibrillation: Refase Registry

Abstract

Aim: To analyse the effectiveness and safety of DOAC (direct oral anticoagulants) in non-valvular atrial fibrillation (NVAF) patients attending clinical practice.

Methods: Retrospective study of AF patients who started treatment with DOAC from January 1, 2013 to December 31, 2016 in three Spanish hospitals. Mean follow-up was 1.6?years. The primary outcomes were rates of all-cause death, ischaemic stroke, and bleeding. These outcomes were also studied depending on correct dosage adjustment and standard/adjusted dose.

Results: The study included 2494 patients (age = 76.0?±?9.5?years, CHA₂DS₂-VASc = 4.0?±?1.6). The most prescribed DOAC was rivaroxaban (41.1%). Patients taking dabigatran were the youngest (mean age = 73.1?±?10.3 years), with better kidney function (mean CrCl = 80.6?±?35.8?ml/min) and lower CHA₂DS₂-VASc (3.7?±?1.4) and HAS-BLED (2.1?±?0.9) scores. Patients taking apixaban were the oldest, and had the highest CHA2DS2-VASc and HAS-BLED scores (4.3?±?1.6 and 2.6?±?0.9, respectively). Rates of stroke/major bleeding/intracranial bleeding were 1.8/3.0/0.3 events per 100 patient-years, respectively, with no differences among DOAC. Based on dose adjustment according to technical data, it was observed that 517 patients (23.5%) received DOAC doses inconsistent with labelling (p?<?.001) and, within this group, under-dosed patients had a higher death rate although it did not reach a significant result after multivariate adjustment.

Conclusions: The results of safety and efficacy are very similar to those of other previously published national registries. There were no differences among the different types of DOAC regarding outcomes. However, it was found that people taking the adjusted dose of the drug seemed to have a higher risk of death. A non-negligible proportion of patients received DOAC doses inconsistent with labelling (mostly underdose).     

Insights from the dabigatran versus warfarin in patients with atrial fibrillation (RE-LY) trial

Oral anticoagulants such as warfarin have been used widely for the treatment of venous thromboembolism and stroke prevention in atrial fibrillation (AF) patients. Warfarin has significant limitations and also requires frequent monitoring. Thus, there is an unmet need, with the quest for alternative oral anticoagulants with stable pharmacokinetics and pharmacodynamics that do not need monitoring. The paper under evaluation provides us with up-to-date information on the safety and efficacy of a new oral anticoagulant, dabigatran, compared with warfarin for stroke prevention in AF patients.     

New evidences for old concerns with oral anticoagulation in atrial fibrillation: focus on dabigatran

Introduction: Nonvalvular atrial fibrillation (NVAF) is associated with a fivefold excess risk of stroke. Antithrombotic therapy is crucial to reduce the risk of stroke. During past decades, vitamin K antagonists (warfarin or acenocoumarol) have been widely used for this purpose. However, they have several disadvantages that limit their daily use in clinical practice.

Areas covered: In patients with NVAF at risk of stroke, the randomized evaluation of long-term anticoagulation therapy (RE-LY) trial demonstrated that, compared with warfarin, dabigatran 150 mg b.i.d. was associated with lower rates of stroke and systemic embolism but similar rates of major hemorrhage, whereas dabigatran 110 mg b.i.d. exhibited similar rates of stroke and systemic embolism, but lower rates of major hemorrhage. Fortunately, data about dabigatran are not limited to RE-LY trial. In fact, many substudies have been drawn, providing new and important evidences about the benefits of dabigatran.

Expert opinion: The most recent evidences about efficacy and safety of dabigatran in patients with NVAF, focusing on different substudies of RE-LY trial, are reviewed. In summary, dabigatran is beneficial not only in general population with NVAF but also in different subgroups of patients or different clinical settings (i.e., CHADS2 score, INR control, type of AF, elderly, previous transient ischemic attack or stroke, cardioversion and so on).     

非瓣膜性房颤患者应用达比加群相关出血事件的危险因素分析

目的:分析非瓣膜性房颤患者服用达比加群发生出血的危险因素。方法:本研究是一个单中心、回顾性研究,旨在探索达比加群相关出血事件的危险因素。应用某院电子病历管理系统,收集于2014年11月-2016年7月期间517例接受达比加群抗凝治疗的非瓣膜性房颤患者资料,包括患者年龄、性别、体质量、血常规、血脂、血糖、肝肾功能、合并疾病以及治疗药物等。结果:所有纳入研究的患者住院期间共有49例(9.5%)发生了出血,468例(90.5%)未发生出血。2组患者在性别、体质量、用药前红细胞压积、血小板计数、肝功能、血脂、空腹血糖、凝血指标以及合并高血脂症、肝功能不全和心功能不全方面的差异无显著性。然而,出血事件往往倾向发生于老年以及合并高血压和糖尿病的患者。肾功能不全是导致达比加群出血的重要危险因素之一,其中肌酐>115μmol·L^-1、估测肾小球滤过率<60mL/(min·1.73m^2)会显著增加房颤患者服用达比加群发生出血不良反应的风险。此外,联合应用抗血小板药物可增加房颤患者服用达比加群的出血风险,当联合应用双联抗血小板药物时出血风险显著升高(OR=4.16,95%CI 2.07~8.37)。结论:非瓣膜性房颤患者使用达比加群发生出血事件的危险因素有高龄,合并高血压、糖尿病,肌酐>115μmol·L^-1,肾小球滤过率<60mL/(min·1.73m^2)以及联合应用抗血小板药物。     

达比加群酯治疗老年非瓣膜性心房颤动的有效性和安全性评价

目的 探讨达比加群酯治疗老年非瓣膜性心房颤动的有效性和安全性,为临床治疗和合理用药提供参考。方法 采用自身对照的研究方法,收集2020年12月-2021年6月在上海市第七人民医院住院或门诊的老年非瓣膜性房颤患者80例,年龄65~80岁。给予口服达比加群酯胶囊110 mg/次,每天2次（早、晚各1次）,治疗6个月。随访,观察服药1个月、6个月后患者的凝血功能指标,包括活化部分凝血活酶时间(APTT)、血浆凝血酶时间(TT)、纤维蛋白原(FIB)和D-二聚体(D-D);肝功能指标,包括丙氨酸氨基转移酶(ALT)、谷草转氨酶(AST)和总胆红素(TBIL),肾功能指标,包括尿素(UREA)和肾小球滤过率估计值(eGFR);血常规指标,包括血红蛋白量(HGB)和红细胞沉降率(ESR)。结果 患者服用达比加群酯治疗1个月、6个月后与服药前比较：APTT、TT均有升高,差异有统计学意义（P<0.05）;肝功能指标、肾功能指标、血常规指标差异无统计学意义（P>0.05）;共发生25例不良事件,不良事件发生率为31.25%,并未发生严重出血和威胁生命或器官衰竭的出血。结论 达比加群酯在治疗老年非瓣膜性心房颤动方面,有较好的疗效和安全性。     

The hidden costs of anticoagulation in hospitalized patients with non-valvular atrial fibrillation

Introduction: Non-valvular atrial fibrillation (NVAF) and ischemic stroke are collectively associated with annual hospital costs of tens of billions of dollars in the USA. Oral anticoagulant (OAC) treatment with warfarin reduces the risk of stroke in patients with NVAF. Unfortunately, because of the complexity of warfarin therapy and potential for adverse events (AEs), many patients who might benefit go untreated or receive suboptimal therapy, increasing their stroke and/or bleeding risk.

Areas covered: This review explores current hospital costs and resource utilization for NVAF patients on warfarin therapy and the potential impact of newer OACs in this area.

Expert opinion: Many ischemic strokes could be prevented through wider use of OACs. Further, admissions due to anticoagulant-associated AEs could be reduced by optimizing OAC therapy. In the hospital, specialized anticoagulation services can decrease costs by improving the effectiveness of warfarin management, empowering patients through education and optimizing care transitions. With fewer interactions and no dose titration or monitoring required, the novel OACs (NOACs) have the potential to further decrease inpatient resource utilization and costs. It is important that, as data become available, inpatient costs are included in cost–benefit comparisons between warfarin and the NOACs.     

达比加群酯预防房颤患者卒中的临床研究

目的 观察达比加群酯预防房颤患者卒中的疗效及安全性。方法 纳入房颤患者80例均符合抗凝治疗指征。按照奇偶数法随机分为观察组（n=40）和对照组（n=40）。观察组给予达比加群酯110 mg,2次/d;对照组给予华法林2.5 mg/d,并定期测定国际标准化比值（INR）,根据INR调整剂量。两组疗程均为6个月。记录两组患者卒中、全身性栓塞和大出血发生情况。两组患者出院时检查凝血酶原时间（PT）、活化部分凝血活酶时间（APTT）、纤维蛋白原（FIB）和D-二聚体等凝血指标。结果 观察组患者卒中/全身性栓塞的发生率为17.5%,对照组为37.5%,两组患者卒中/全身性栓塞发生率有统计学差异（P<0.05）;观察组患者大出血发生率显著低于对照组,差异有统计学意义（P<0.05）。两组患者凝血功能指标差异均无统计学意义。治疗后,两组血脂水平均较治疗前显著改善,同组治疗前后比较差异有统计学意义（P<0.05）;且观察组血脂水平改善更为明显,组间差异有统计学意义（P<0.05）。结论 与华法林比较,对有房颤患者行抗凝治疗达比加群酯具备同等疗效,且安全性更高。     

Effectiveness and safety of rivaroxaban in nonvalvular atrial fibrillation: data from a contemporary Spanish registry

Objective: To ascertain the clinical profile, management and rates of thromboembolic and bleeding complications in a contemporary cohort of patients with nonvalvular atrial fibrillation (NVAF) on rivaroxaban treatment, with a particular focus on some subgroups of patients.

Methods: Retrospective study that included all NVAF patients who started treatment with rivaroxaban for the prevention of stroke or systemic embolism between December 2012 and December 2015. Rates of outcomes (stroke, nonfatal myocardial infarction, major bleeding, intracranial bleeding and death) during follow-up were calculated.

Results: A total of 732 patients (mean age 76.4?±?9.2?years; 54.5% women) were included. Comorbidities were common (hypertension 87.5%; diabetes 26.5%; renal insufficiency 24.6%; prior stroke/transient ischemic attack 16.8%). Mean CHA₂DS₂-VASc was 3.9?±?1.5 and HAS-BLED 2.3?±?0.9; 61.9% of patients were rivaroxaban naïve users. After a mean treatment period of 22.7?±?7.4?months, rates of stroke, nonfatal myocardial infarction, major bleeding, intracranial bleeding and death were 1.8, 1.0, 3.2, 0.4 and 5.5 events per 100 patient-years, respectively. Rates of stroke and death were higher in patients >75?years (vs. ≤75?years) and in patients with prior stroke/transient ischemic attack or renal insufficiency. Rates of major bleeding were higher among patients >75?years and in patients with prior stroke/transient ischemic attack.

Conclusions: In this contemporary Spanish cohort of NVAF patients on rivaroxaban, patients had many comorbidities, a high thromboembolic risk and a moderate bleeding risk. Overall, rates of stroke and bleeding complications were low and similar to other previous studies. These data suggest that rivaroxaban is effective and safe in routine practice.     

Strategies for improving dabigatran adherence for stroke prevention in patients with non-valvular atrial fibrillation: education and drug intake reminders (FACILITA study)

Objective To assess the efficacy of a mixed intervention, educational, and reminder calendar of the intake, as a strategy to improve therapeutic adherence with dabigatran in patients with non-valvular atrial fibrillation (NVAF).

Methods This was a prospective, longitudinal, multi-center study, carried out in 110 specialized healthcare centers in Spain. Seven hundred and twenty-six patients treated with dabigatran prescribed for stroke prevention were included. A cluster randomization was performed based on two groups: (1) Control Group (CG) as usual clinical practice, and (2) Intervention Group (IG) with a mixed strategy: (a) Healthcare education, and (b) Use of a reminder calendar for taking the anticoagulant medication. Three visits took place: baseline and follow-up at 6 and 12 months. Compliance was measured by using electronic monitors (MEMS). Average adherence percentage (%; Average AP) and daily compliance (%; Daily AP) was calculated. A patient was considered adherent when AP was 80–100%.

Results Six hundred and twenty-five patients completed the study (315 in the IG and 310 in the CG). Daily AP was 91.97% at 6 months and 91.05% after 12 months in the IG and 82.26% and 82.63% in the CG. Average adherence was 90.79% and 89.20% in the IG and 64.51% and 63.22% in the CG at 6 and 12 months, respectively. Significant differences were observed in the Daily AP and Average AP, with higher percentages in the IG. In the non-adherents group, the number of concomitant drugs, baseline, and 6 months SBP values, 6 and 12 months DBP values, and weight, total cholesterol, and LDL cholesterol were significantly higher. The number needed to treat (NNT) was 3.84 patients to prevent one non-adherence.

Conclusions A mixed intervention, consisting of patient education and a simple calendar reminder of drug intake, is an effective strategy to improve dabigatran therapeutic adherence in patients with NVAF. The percentage of adherence with dabigatran was high.     

Therapeutic compliance with rivaroxaban in preventing stroke in patients with non-valvular atrial fibrillation: CUMRIVAFA study

Objective: To assess compliance with treatment with rivaroxaban in patients with non-valvular atrial fibrillation.

Methods: Prospective, longitudinal, multicenter study, developed in 160 Spanish primary or specialized care centers. We included 412 patients treated with rivaroxaban, prescribed for stroke prevention. Three visits were conducted: baseline, 6 and 12 months. Compliance was measured by using electronic monitors (MEMSs) that use a digital record in the form of a microchip in the lid of the drug container that automatically controls its opening and registers the time and date of the opening. We calculated the average compliance percentage (CP), global and daily compliance. We considered compliance to be when CP was 80–100%.

Results: Three hundred and seventy patients ended the study (mean age 75.19, SD: 7.5 years). Global compliance was 84.1% (CI?=?79.21–88.99%) and 80.3% (CI?=?74.98–85.62%) after 6 and 12 months respectively. Daily compliance was 83.5% (CI?=?78.53–88.57%) and 80% (CI?=?74.65–85.35%) at 6 and 12 months. Significant differences in the CP between 6 and 12 months were observed. Global CP was 90.77% after 6 months and 89.65% at the end of the study. Daily CP was 90.14% and 87.66% at 6 and 12 months. There were significant CP differences between 6 and 12 months. Non-compliance was associated with a higher number of concomitant diseases, number of drugs taken and weight.

Conclusions: The percentage of compliance with rivaroxaban was high. A profile of variables that need to be modified in current medical practice, associated with non-compliance, was detected.     

Stroke prevention in atrial fibrillation patients

Importance of the field: Atrial fibrillation (AF) is the most common cardiac arrhythmia encountered in clinical practice and is associated with an increased risk of stroke, mortality and significant morbidity. Given the rapidly increasing incidence and prevalence of AF, and the resulting public health burden of the consequences associated with this arrhythmia, stroke prevention is an extremely important topic.

Areas covered in this review: This review covers the epidemiology of AF, the pathophysiology of ischemic stroke in AF and current antithrombotic therapy choices for stroke prevention in this condition. In addition, this article discusses important topics such as the assessment of stroke risk stratification and bleeding risk assessment, which are key issues in deciding upon thromboprophylaxis for AF patients. Finally, the review highlights the advent of new anticoagulant therapies and discusses the future challenges for researchers in this area.

What the reader will gain: This review summarizes all of the major antithrombotic trials conducted in AF patients over the last twenty years and highlights the importance of anticoagulation therapy for the prevention of stroke, after appropriate individual stroke and bleeding risk assessment.

Take home message: Assessment of individual stroke risk and bleeding risk is key in determining appropriate thromboprophylaxis for AF patients, given the associated thromboembolic and hemorrhagic complications. The availability of newer, safer and more convenient drugs will mean that oral anticoagulation is available for a larger proportion of AF patients who may benefit from it.     

Stroke risk reduction outweighed bleeding risk increase from vitamin K antagonist treatment among nonvalvular atrial fibrillation patients with high stroke risk and low bleeding risk

Objective: Warfarin is widely used for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF). We compared the rates of stroke and major bleeding in NVAF patients with a high stroke risk and low bleeding risk profile during warfarin treated (W+) and warfarin untreated (W?) periods.

Method: Insurance claims from six commercial, Medicaid or Medicare databases were analyzed from 2000 to 2014. NVAF patients treated with warfarin, with a CHADS₂/CHA₂DS₂-VASc score ≥2, and an ATRIA score ≤3 at baseline were identified. Incidence rate ratios (IRRs) of stroke and major bleeding were calculated for W?+?versus W? episodes of person-time, as well as for first 30 days versus beyond 30 days of W?+?episodes.

Results: Among 316,145 patients, anticoagulant prophylaxis with warfarin significantly reduced stroke risk, with IRRs ranging from 0.48 (95% CI: 0.46–0.51) to 0.80 (95% CI: 0.70–0.91), and increased major bleeding risk, with IRRs ranging from 1.13 (95% CI: 1.10–1.15) to 1.95 (95% CI: 1.10–3.45). Stroke and major bleeding rates were higher during the first 30 days of W?+?than beyond.

Conclusion: In NVAF patients at high risk for stroke and low risk for bleeding, our data confirm the effectiveness of anticoagulation for stroke prevention. The decrease in stroke risk of anticoagulation may outweigh the risk of major bleeding events, particularly among elderly patients. Potential risks of warfarin during initiation warrant attention, especially among patients who stop and start therapy repeatedly.     

Warfarin versus dabigatran etexilate: an assessment of efficacy and safety in patients with atrial fibrillation

Introduction: Oral anticoagulation is the mainstay for stroke and thromboembolic event prevention in patients with atrial fibrillation (AF). Given limitations of warfarin therapy, non-vitamin K oral anticoagulants have been developed including direct thrombin inhibitors (i.e., dabigatran etexilate). Dabigatran etexilate has been tested thoroughly in terms of efficacy and safety in clinical trials and studies, involving ‘real-world’ cohorts. In this review, currently available evidence in patients with non-valvular AF is discussed.

Areas covered: The pharmacology, efficacy and safety, and current aspects of use of dabigatran etexilate in patients with non-valvular AF are reviewed in a comparative manner to warfarin both for chronic anticoagulation and in different clinical settings.

Expert opinion: Dabigatran etexilate appeared to have several pharmacokinetic and pharmacodynamic advantages over warfarin, as well as a favorable efficacy and safety profile being at least noninferior and often superior to warfarin in patients with non-valvular AF. The latter was shown in the clinical trials, meta-analyses and studies with ‘real-world’ data. Currently ongoing trials will expand the body of evidence on warfarin and will aid decision making in currently controversial areas. Important limitations of dabigatran etexilate include contraindications for its use in patients with prosthetic heart valves and end-stage chronic kidney disease.