Comparison of the Effectiveness and Safety of Apixaban, Dabigatran, Rivaroxaban, and Warfarin in Newly Diagnosed Atrial Fibrillation

Real-World Adherence and Persistence to Direct Oral Anticoagulants in Patients With Atrial Fibrillation: A Systematic Review and Meta-Analysis

BACKGROUND

Stroke reduction with direct oral anticoagulants (DOACs) in atrial fibrillation (AF) is dependent on adherence and persistence in the real-world setting. Individual study estimates of DOAC adherence/persistence rates have been discordant. Our aims were to characterize real-world observational evidence for DOAC adherence/persistence and evaluate associated clinical outcomes in patients with AF.

METHODS AND RESULTS

PubMed, EMBASE, and CINAHL were searched from inception to June 2018. Observational studies that reported real-world DOAC adherence/persistence in patients with AF were included. Study quality was assessed using the Newcastle-Ottawa Scale. Meta-analyses for pooled estimates were performed using DerSimonian and Laird random-effects models. Outcomes included DOAC mean proportion of days covered or medication possession ratio, proportion of good adherence (proportion of days covered/medication possession ratio ≥80%), persistence, DOAC versus vitamin K antagonists persistence, and clinical outcomes associated with nonadherence/nonpersistence. Forty-eight observational studies with 594 784 unique patients with AF (59% male; mean age 71 years) were included. The overall pooled mean proportion of days covered/medication possession ratio was 77% (95% CI, 75%-80%), proportion of patients with good adherence was 66% (95% CI, 63%-70%), and proportion persistent was 69% (95% CI, 65%-72%). The pooled proportion of patients with good adherence was 71% (95% CI, 64%-78%) for apixaban, 60% (95% CI, 52%-68%) for dabigatran, and 70% (95% CI, 64%-75%) for rivaroxaban. Similar patterns were found for pooled persistence by agent. The pooled persistence was higher with DOACs than vitamin K antagonists (odds ratio, 1.44 [95% CI, 1.12-.86]). DOAC nonadherence was associated with an increased risk of stroke (hazard ratio, 1.39 [95% CI, 1.06-1.81]).

CONCLUSIONS

Suboptimal adherence and persistence to DOACs was common in patients with AF, with 1 in 3 patients adhering to their DOAC <80% of the time, which was associated with poor clinical outcomes in nonadherent patients. Although it is convenient that DOACs do not require laboratory monitoring, greater effort in monitoring for and interventions to prevent nonadherence may be necessary to optimize stroke prevention. Increased clinician awareness of DOAC nonadherence may help identify at-risk patients.

Meta-analysis of Antithrombotic Therapy in Patients With Atrial Fibrillation Undergoing Percutaneous Coronary Intervention

For patients with atrial fibrillation (AF) who undergo percutaneous coronary intervention (PCI), antithrombotic therapy including oral anticoagulants and antiplatelets are indicated. The optimal combination is not known. We investigated the efficacy and safety of different antithrombotic strategies in patients with AF undergoing PCI. PUBMED and EMBASE were searched through September 2019 for randomized trials investigating the efficacy and safety of different antithrombotic strategies in patients with AF who underwent PCI and/or acute coronary syndrome. Nine antithrombotic strategies were compared including combinations of vitamin K antagonist (VKA) with dual antiplatelet therapy (DAPT) or P2Y₁₂ inhibitor, combinations of direct oral anticoagulants (DOAC) (apixaban, dabigatran, rivaroxaban, and edoxaban) with DAPT or P2Y₁₂ inhibitor (clopidogrel, prasugrel, and ticagrelor). The primary safety outcome was trial defined primary bleeding outcome. The primary efficacy outcome was trial defined major adverse cardiovascular events. Our search identified 5 eligible trials that enrolled a total of 11,532 patients and compared 9 treatment strategies. VKA + DAPT significantly increased bleeding when compared with most combinations (for example, vs VKA + P2Y₁₂ inhibitor: odds ratio 2.11; 95% confidence interval [1.76 to 2.52], p <0.001). Of all the combinations, apixaban + P₂Y₁₂ inhibitor showed the lowest bleeding risk (for example, vs VKA + P2Y₁₂ inhibitor: odds ratio 0.63; 95% confidence interval [0.51 to 0.78], p <0.001) and was ranked the best treatment. There were no significant differences in ischemic outcome of major adverse cardiovascular events between various antithrombotic regimens. In conclusion, in patients with AF undergoing PCI, apixaban + P2Y₁₂ inhibitors were associated with lowest bleeding compared with other regimens including other DOACs + P2Y₁₂ inhibitors with no increase in ischemic outcomes.

Race/Ethnicity and Sex-Related Differences in Direct Oral Anticoagulant Initiation in Newly Diagnosed Atrial Fibrillation: A Retrospective Study of Medicare Data

BACKGROUND

Atrial fibrillation (AF) is the most common heart rhythm disorder and is associated with a 5-fold increased risk of ischemic stroke. Racial/ethnic minorities and women with AF have higher rates of stroke compared to white individuals and men respectively. Oral anticoagulation reduces the risk of stroke, yet prior research has described racial/ethnic and sex-based variation in its use. We sought to examine the initiation of any oral anticoagulant (warfarin or direct-acting oral anticoagulants, DOACs) by race/ethnicity and sex in patients with incident, non-valvular AF. Further in those who initiated any anticoagulant, we examined DOAC vs. warfarin initiation by race/ethnicity and sex.

METHODS

We used claims data from a 5% sample of Medicare beneficiaries to identify patients with incident AF from 2012 to 2014, excluding those without continuous Medicare enrollment. We used logistic regression to assess the association between race/ethnicity (white, black, Hispanic), sex, and oral anticoagulant initiation (any, warfarin vs. DOAC), adjusting for sociodemographics, medical comorbidities, stroke and bleeding risk.

RESULTS

The cohort of 42,952 patients with AF included 17,935 women, 3282 blacks, and 1958 Hispanics. Overall OAC initiation was low (49.2% whites, 48.1% blacks, 47.5% Hispanics, 48.1% men, and 51.5% women). After adjusting, blacks (odds ratio (OR) 0.84; 95% CI, 0.78-0.91) were less likely than whites to initiate any oral anticoagulant with no difference observed between Hispanics and whites (OR 0.92; 95% CI, 0.83-1.01). Women were less likely than men to initiate any oral anticoagulant, OR 0.59 (95% CI 0.55-0.64). Among initiators of oral anticoagulation, DOAC use was low (35.8% whites, 29.3% blacks, 40.0% Hispanics, 41.6% men, and 42.4% women). After adjusting, blacks were less likely to initiate DOACs than whites, OR 0.75 (95% CI 0.66-0.85); the odds of DOAC initiation did not differ between Hispanic and white patients or between men and women.

CONCLUSION

In a national cohort of Medicare beneficiaries with newly-diagnosed AF, overall oral anticoagulant initiation was lower in blacks and women, with no difference observed by Hispanic ethnicity. Among oral anticoagulant initiators, blacks were less likely to initiate novel DOACs, with no differences identified by Hispanic ethnicity or sex. Identifying modifiable causes of treatment disparities is needed to improve quality of care for all patients with AF.

The 2018 European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation

The current manuscript is the second update of the original Practical Guide, published in 2013 [Heidbuchel et al. European Heart Rhythm Association Practical Guide on the use of new oral anticoagulants in patients with non-valvular atrial fibrillation. Europace 2013;15:625-651; Heidbuchel et al. Updated European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist anticoagulants in patients with non-valvular atrial fibrillation. Europace 2015;17:1467-1507]. Non-vitamin K antagonist oral anticoagulants (NOACs) are an alternative for vitamin K antagonists (VKAs) to prevent stroke in patients with atrial fibrillation (AF) and have emerged as the preferred choice, particularly in patients newly started on anticoagulation. Both physicians and patients are becoming more accustomed to the use of these drugs in clinical practice. However, many unresolved questions on how to optimally use these agents in specific clinical situations remain. The European Heart Rhythm Association (EHRA) set out to coordinate a unified way of informing physicians on the use of the different NOACs. A writing group identified 20 topics of concrete clinical scenarios for which practical answers were formulated, based on available evidence. The 20 topics are as follows i.e., (1) Eligibility for NOACs; (2) Practical start-up and follow-up scheme for patients on NOACs; (3) Ensuring adherence to prescribed oral anticoagulant intake; (4) Switching between anticoagulant regimens; (5) Pharmacokinetics and drug-drug interactions of NOACs; (6) NOACs in patients with chronic kidney or advanced liver disease; (7) How to measure the anticoagulant effect of NOACs; (8) NOAC plasma level measurement: rare indications, precautions, and potential pitfalls; (9) How to deal with dosing errors; (10) What to do if there is a (suspected) overdose without bleeding, or a clotting test is indicating a potential risk of bleeding; (11) Management of bleeding under NOAC therapy; (12) Patients undergoing a planned invasive procedure, surgery or ablation; (13) Patients requiring an urgent surgical intervention; (14) Patients with AF and coronary artery disease; (15) Avoiding confusion with NOAC dosing across indications; (16) Cardioversion in a NOAC-treated patient; (17) AF patients presenting with acute stroke while on NOACs; (18) NOACs in special situations; (19) Anticoagulation in AF patients with a malignancy; and (20) Optimizing dose adjustments of VKA. Additional information and downloads of the text and anticoagulation cards in different languages can be found on an EHRA website (www.NOACforAF.eu).

Apixaban-induced haematoma causing small bowel intussusception

Apixaban (Eliquis) is a direct acting oral anticoagulant (DOAC) indicated for treatment of deep vein thrombosis, non-valvular atrial fibrillation, pulmonary embolism and postoperative venous thromboprophylaxis following hip or knee replacement. Complications are minimal and include, but are not limited to, bleeding and intracranial haemorrhage, and haematoma formation. Our patient is a 73-year-old woman who presented with clinical and radiographic findings of small bowel obstruction. She was found to be taking apixaban for atrial fibrillation. CT scan showed small bowel intussusception. She underwent an exploratory laparotomy and resection of the small bowel intussusception with primary side-to-side anastomosis. Histopathological examination showed that the intussusception was caused by an intramural haematoma. This case presents a rare instance of adult intussusception caused by a DOAC. To our knowledge, no case of intussusception caused by apixaban has yet been found in literature.

Effectiveness and Safety of Oral Anticoagulants Among Nonvalvular Atrial Fibrillation Patients

Supplemental Digital Content is available in the text.

Background and Purpose—

This ARISTOPHANES study (Anticoagulants for Reduction in Stroke: Observational Pooled Analysis on Health Outcomes and Experience of Patients) used multiple data sources to compare stroke/systemic embolism (SE) and major bleeding (MB) among a large number of nonvalvular atrial fibrillation patients on non–vitamin K antagonist oral anticoagulants (NOACs) or warfarin.

Methods—

A retrospective observational study of nonvalvular atrial fibrillation patients initiating apixaban, dabigatran, rivaroxaban, or warfarin from January 1, 2013, to September 30, 2015, was conducted pooling Centers for Medicare and Medicaid Services Medicare data and 4 US commercial claims databases. After 1:1 NOAC-warfarin and NOAC-NOAC propensity score matching in each database, the resulting patient records were pooled. Cox models were used to evaluate the risk of stroke/SE and MB across matched cohorts.

Results—

A total of 285 292 patients were included in the 6 matched cohorts: 57 929 apixaban-warfarin, 26 838 dabigatran-warfarin, 83 007 rivaroxaban-warfarin, 27 096 apixaban-dabigatran, 62 619 apixaban-rivaroxaban, and 27 538 dabigatran-rivaroxaban patient pairs. Apixaban (hazard ratio [HR], 0.61; 95% CI, 0.54–0.69), dabigatran (HR, 0.80; 95% CI, 0.68–0.94), and rivaroxaban (HR, 0.75; 95% CI, 0.69–0.82) were associated with lower rates of stroke/SE compared with warfarin. Apixaban (HR, 0.58; 95% CI, 0.54–0.62) and dabigatran (HR, 0.73; 95% CI, 0.66–0.81) had lower rates of MB, and rivaroxaban (HR, 1.07; 95% CI, 1.02–1.13) had a higher rate of MB compared with warfarin. Differences exist in rates of stroke/SE and MB across NOACs.

Conclusions—

In this largest observational study to date on NOACs and warfarin, the NOACs had lower rates of stroke/SE and variable comparative rates of MB versus warfarin. The findings from this study may help inform the discussion on benefit and risk in the shared decision-making process for stroke prevention between healthcare providers and nonvalvular atrial fibrillation patients.

Clinical Trial Registration—

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT03087487.

Patient characteristics and stroke and bleeding events in nonvalvular atrial fibrillation patients treated with apixaban and vitamin K antagonists: a Spanish real-world study

Aim: To compare the risk of stroke, systemic thromboembolism and bleeding, in patients initiating apixaban or acenocoumarol for the treatment of nonvalvular atrial fibrillation. Methods: An observational, retrospective study was performed using medical records of patients who initiated apixaban or acenocoumarol between 2015 and 2017. Propensity score matching was used to match patients; stroke, systemic thromboembolism, major and minor bleeding events were compared between the matched patients. Results: Patients who were prescribed apixaban had a lower rate of systemic embolism/stroke (hazard ratio [HR] = 0.54; 95% CI: 0.38–0.78; p = 0.001), minor bleeding (HR = 0.64; 95% CI: 0.52–0.79; p < 0.001) and major bleeding (HR = 0.51; 95% CI: 0.37–0.72; p < 0.001). Conclusion: Patients prescribed apixaban for the treatment of nonvalvular atrial fibrillation had lower rates of thromboembolic events and minor/major bleeding than patients on acenocoumarol.

Incidence of direct oral anticoagulant use in patients with nonvalvular atrial fibrillation and characteristics of users in 6 European countries (2008-2015): A cross-national drug utilization study

Aims

To estimate the incidence of direct oral anticoagulant drug (DOAC) use in patients with nonvalvular atrial fibrillation and to describe user and treatment characteristics in 8 European healthcare databases representing 6 European countries.

Methods

Longitudinal drug utilization study from January 2008 to December 2015. A common protocol approach was applied. Annual period incidences and direct standardisation by age and sex were performed. Dose adjustment related to change in age and by renal function as well as concomitant use of potentially interacting drugs were assessed.

Results

A total of 186 405 new DOAC users (age ≥18 years) were identified. Standardized incidences varied from 1.93–2.60 and 0.11–8.71 users/10 000 (2011–2015) for dabigatran and rivaroxaban, respectively, and from 0.01–8.12 users/10 000 (2012–2015) for apixaban. In 2015, the DOAC incidence ranged from 9 to 28/10 000 inhabitants in SIDIAP (Spain) and DNR (Denmark) respectively. There were differences in population coverage among the databases. Only 1 database includes the total reference population (DNR) while others are considered a population representative sample (CPRD, BIFAP, SIDIAP, EGB, Mondriaan). They also varied in the type of drug data source (administrative, clinical). Dose adjustment ranged from 4.6% in BIFAP (Spain) to 15.6% in EGB (France). Concomitant use of interacting drugs varied between 16.4% (SIDIAP) and 70.5% (EGB). Cardiovascular comorbidities ranged from 25.4% in Mondriaan (The Netherlands) to 82.9% in AOK Nordwest (Germany).

Conclusion

Overall, apixaban and rivaroxaban increased its use during the study period while dabigatran decreased. There was variability in patient characteristics such as comorbidities, potentially interacting drugs and dose adjustment. (EMA/2015/27/PH).

Stroke and Systemic Thromboembolism Prevention in People Living With Human Immunodeficiency Virus With Atrial Fibrillation: A Review of Its Implications for Clinical Practice

In the last few decades, types of diseases affecting people living with human immunodeficiency virus (PLHIV) have shifted as the population ages, with cardiovascular disease becoming a leading cause of death in this population. Atrial fibrillation (AF) is an increasingly common arrhythmia both in the general population and in PLHIV, with an estimated prevalence of 2% to 3% among PLHIV. Prevention of stroke and systemic thromboembolism (SSE) with antithrombotic therapy is a cornerstone of AF treatment and substantially decreases AF-related morbidity and mortality. Although updated guidelines extensively discuss this issue, they do not address the peculiarities of PLHIV. The role of human immunodeficiency virus (HIV) infection as an independent factor for SSE in individuals with AF and whether the presence of HIV should alter the threshold for SSE thromboprophylaxis are unknown. Nevertheless, a growing body of evidence describes the increasing burden of comorbidities such as hypertension and stroke in PLHIV, which predispose them to AF and SSE. In the absence of HIV-specific AF guidelines, PLHIV with AF should be comprehensively assessed for their risk of SSE and bleeding using commonly available scores despite them having been primarily validated in the non-HIV population. Both vitamin K antagonists and direct oral anticoagulants can be used in PLHIV. Addressing HIV-related comorbidities and potential drug-drug interactions with antiretrovirals is crucial to prevent SSE and reduce adverse reactions of oral anticoagulants. This review summarizes the current guidelines for SSE prevention in patients with AF and describes key considerations for their implementation among PLHIV receiving antiretroviral therapy.

Outcome reporting from clinical trials of non-valvular atrial fibrillation treated with traditional Chinese medicine or Western medicine: a systematic review

OBJECTIVES

To examine variation in outcomes, outcome measurement instruments (OMIs) and measurement times in clinical trials of non-valvular atrial fibrillation (NVAF) and to identify outcomes for prioritisation in developing a core outcome set (COS) in this field.

DESIGN

This study was a systematic review.

DATA SOURCES

Clinical trials published between January 2015 and March 2019 were obtained from PubMed, the Cochrane Library, Web of Science, Wanfang Database, the China National Knowledge Infrastructure and SinoMed.

ELIGIBILITY CRITERIA

Randomised controlled trials (RCTs) and observational studies were considered. Interventions included traditional Chinese medicine and Western medicine. The required treatment duration or follow-up time was ≥4 weeks. The required sample size was ≥30 and≥50 in each group in RCTs and observational studies, respectively. We excluded trials that aimed to investigate the outcome of complications of NVAF, to assess the mechanisms or pharmacokinetics, or for which full text could not be acquired.

DATA EXTRACTION AND SYNTHESIS

The general information and outcomes, OMIs and measurement times were extracted. The methodological and outcome reporting quality were assessed. The results were analysed by descriptive analysis.

RESULTS

A total of 218 articles were included from 25 255 articles. For clinical trials of antiarrhythmic therapy, 69 outcomes from 16 outcome domains were reported, and 28 (31.82%, 28/88) outcomes were reported only once; the most frequently reported outcome was ultrasonic cardiogram. Thirty-one outcomes (44.93%, 31/69) were provided definitions or OMIs; the outcome measurement times ranged from 1 to 20 with a median of 3. For clinical trials of anticoagulation therapy, 82 outcomes from 18 outcome domains were reported; 38 (29.23%, 38/130) outcomes were reported only once. The most frequently reported outcome was ischaemic stroke. Forty (48.78%, 40/82) outcomes were provided OMIs or definitions; and the outcome measurement times ranged from 1 to 27 with a median of 8.

CONCLUSION

Outcome reporting in NVAF is inconsistent. Thus, developing a COS that can be used in clinical trials is necessary.

Effectiveness and Safety of Rivaroxaban 15 or 20 mg Versus Vitamin K Antagonists in Nonvalvular Atrial Fibrillation

Supplemental Digital Content is available in the text.

We compared the 1-year safety and effectiveness of rivaroxaban 15 mg (R15) or rivaroxaban 20 mg (R20) to vitamin K antagonists (VKAs) in patients with nonvalvular atrial fibrillation.

Evaluating utilization patterns of oral anticoagulants in routine care

Essentials Unlike warfarin, treatment with DOACs do not require regular plasma level monitoring. We compared persistence of patients treated with DOACs compared to warfarin. Persistence at 12 months was higher for all DOACs compared to warfarin. Persistence to anticoagulant therapy was generally poor in commercially insured patients.

BACKGROUND

Direct oral anticoagulants (DOACs) were developed as an alternative to vitamin K antagonists for a variety of indications. Unlike warfarin, DOACs do not require regular plasma level monitoring.

OBJECTIVE

We investigated whether this simplification in management affects persistence on DOACs vs warfarin.

METHODS

Within two US commercial health insurance databases (MarketScan and Clinformatics™ DataMart), we compared baseline characteristics and evaluated rates of nonpersistence (≥30-day treatment gap or switching) among patients with nonvalvular atrial fibrillation who initiated an oral anticoagulant between October 2010 and September 2015.

RESULTS

In the larger of the two data sources (MarketScan), we identified 166 690 anticoagulant initiators during the study period. After propensity score (PS) matching, 24 141 dabigatran initiators, 26 066 rivaroxaban, and 12 578 apixaban initiators were included along with the 1:1 matched warfarin initiators. The proportion of patients who were nonpersistent after 12 months was lower for DOAC users (dabigatran 66%, rivaroxaban 60%, apixaban 53%) compared with warfarin users (72%). The same relative ranking was observed in direct comparisons among the DOACs after PS-matching. Findings in Clinformatics DataMart were similar.

CONCLUSION

Results from this long-term surveillance program showed that patients who initiated DOACs were more likely to be persistent to therapy compared with those who initiated warfarin. Persistence to anticoagulant therapy was generally poor in commercially insured patients.

Trajectories of Oral Anticoagulation Adherence Among Medicare Beneficiaries Newly Diagnosed With Atrial Fibrillation

Background

Only 50% of atrial fibrillation (AF) patients recommended for oral anticoagulation (OAC) use these medications, and less than half of them adhere to OAC. In a cohort of Medicare beneficiaries newly diagnosed with AF, we identified groups of patients with similar trajectories of OAC use and adherence, and evaluated patient characteristics affecting group membership.

Methods and Results

We selected continuously enrolled Medicare Part D beneficiaries with first AF diagnosis in 2014 to 2015 (n=34 898). We calculated the proportion of days covered with OAC over the first 12 months after diagnosis and identified OAC adherence trajectories using group‐based trajectory models. We constructed multinomial logistic regression models to evaluate how demographics, system‐level factors, and clinical characteristics were associated with group membership. We identified 4 trajectories of OAC adherence: patients who never used OAC (43.8%), late OAC initiators (7.6%), early OAC discontinuers (8.9%), and continuously adherent patients (40.1%). Predictors such as sex, black race, residence in the South, or HAS‐BLED score were associated with not only OAC use, but also the timing of initiation and the likelihood of discontinuation. For example, HAS‐BLED score ≥4 was associated with a higher likelihood of not using OAC (odds ratio 1.35; 95% CI, 1.14–1.62), of late initiation (1.55; 95% CI, 1.11–2.05), and of early discontinuation (odds ratio 1.35; 95% CI, 1.01–1.84).

Conclusions

We identified 4 distinct trajectories of OAC adherence after first AF diagnosis, with <45% of newly diagnosed AF patients belonging to the trajectory group characterized by continuous OAC adherence. Trajectories were associated not only with demographic and clinical characteristics but also with regional factors.

Medication taking behaviors in patients taking warfarin versus direct oral anticoagulants: A systematic review

Introduction: This article aims to compare medication adherence and persistence between warfarin and direct oral anticoagulants (DOACs) and identify reported adherence barriers. As with other chronic illness, medication nonadherence continues to be a problem and appropriate adherence to long-term anticoagulation therapy is needed to improve patient health outcomes and to reduce health expenditure associated with hospitalizations and emergency visits. Areas covered: Warfarin and DOACs such as apixaban, rivaroxaban, edoxaban, and dabigatran have demonstrated effectiveness in the management of atrial fibrillation (AF), deep vein thrombosis (DVT), and pulmonary embolism (PE). Adherence and long-term persistence to oral anticoagulants is highly associated with reduced adverse events. A systematic literature search from 2013 to 2018 examined the primary outcome of adherence and persistence. Expert opinion: Currently, warfarin is less preferred over DOACs due to associated complications like narrow therapeutic window, inconvenience, and increased risk of adverse events. At the same time, the lack of monitoring with DOACs in combination with cost issues may negatively impact medication adherence. Examining adherence barriers identified in the literature is the first step to designing effective interventions aimed at enhancing adherence in this high-risk population.

Comparative Stroke, Bleeding, and Mortality Risks in Older Medicare Patients Treated with Oral Anticoagulants for Nonvalvular Atrial Fibrillation

BACKGROUND

Nonvitamin K antagonist oral anticoagulants (NOACs) are alternatives to warfarin in patients with nonvalvular atrial fibrillation. Randomized trials compared NOACs with warfarin, but none have compared individual NOACs against each other for safety and effectiveness.

METHODS

We performed a retrospective new-user cohort study of patients with nonvalvular atrial fibrillation enrolled in US Medicare who initiated warfarin (n = 183,318), or a standard dose of dabigatran (150 mg twice daily; n = 86,198), rivaroxaban (20 mg once daily; n = 106,389), or apixaban (5 mg twice daily; n = 73,039) between October 2010 and September 2015. Propensity score-adjusted Cox proportional hazards regression was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for the outcomes of thromboembolic stroke, intracranial hemorrhage, major extracranial bleeding, and all-cause mortality, comparing each NOAC with warfarin, and with each other NOAC.

RESULTS

Compared with warfarin, each NOAC was associated with reduced risks of thromboembolic stroke (20%-29% reduction; P = .002 [dabigatran], P < 0.001 [rivaroxaban, apixaban]), intracranial hemorrhage (35%-62% reduction; P < 0.001 [each NOAC]), and mortality (19%-34% reduction; P < .001 [each NOAC]). The NOACs were similar for thromboembolic stroke but rivaroxaban was associated with increased risks of intracranial hemorrhage (vs dabigatran: HR = 1.71; 95% CI, 1.35-2.17), major extracranial bleeding (vs dabigatran: HR = 1.32; 95% CI, 1.21-1.45; vs apixaban: HR = 2.70; 95% CI, 2.38-3.05), and death (vs dabigatran: HR = 1.12; 95% CI, 1.01-1.24; vs apixaban: HR = 1.23; 95% CI, 1.09-1.38). Dabigatran was associated with reduced risk of intracranial hemorrhage (HR = 0.70; 95% CI ,0.53-0.94) and increased risk of major extracranial bleeding (HR = 2.04; 95% CI, 1.78-2.32) compared with apixaban.

CONCLUSIONS

Among patients treated with standard-dose NOAC for nonvalvular atrial fibrillation and warfarin users with similar baseline characteristics, dabigatran, rivaroxaban, and apixaban were associated with a more favorable benefit-harm profile than warfarin. Among NOAC users, dabigatran and apixaban were associated with a more favorable benefit-harm profile than rivaroxaban.

Comparative safety and effectiveness of dabigatran vs. rivaroxaban and apixaban in patients with non-valvular atrial fibrillation: a retrospective study from a large healthcare system

AIMS

We used the US Department of Defense Military Health System database to compare the safety and effectiveness of direct oral anticoagulants (DOACs) in patients with non-valvular atrial fibrillation (NVAF) initiating dabigatran vs. rivaroxaban or apixaban.

METHODS AND RESULTS

Two cohorts of adults with NVAF, newly initiated on standard-dose DOAC, were identified based on clinical approval dates: July 2011-June 2016 for dabigatran (150 mg b.i.d.) or rivaroxaban (20 mg QD) and January 2013-June 2016 for dabigatran (150 mg b.i.d.) or apixaban (5 mg b.i.d.). Propensity score matching (1:1) identified two well-balanced cohorts (dabigatran vs. rivaroxaban n = 12 763 per treatment group; dabigatran vs. apixaban n = 4802 per treatment group). In both cohorts, baseline characteristics and follow-up duration were similar between treatment groups. Patients newly initiating dabigatran had significantly lower risk of major bleeding vs. rivaroxaban [2.08% vs. 2.53%; hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.70-0.97; P = 0.018], while stroke risk was similar (0.60% vs. 0.78%; HR 0.77, 95% CI 0.57-1.04; P = 0.084). The dabigatran vs. apixaban cohort analysis found no differences in risk of major bleeding (1.60% vs. 1.21%; HR 1.37, 95% CI 0.97-1.94; P = 0.070) or stroke (0.44% vs. 0.35%; HR 1.26, 95% CI 0.66-2.39; P = 0.489).

CONCLUSION

Among NVAF patients newly initiated on standard-dose DOAC therapy in this study, dabigatran was associated with significantly lower major bleeding risk vs. rivaroxaban, and no significant difference in stroke risk. For dabigatran vs. apixaban, the reduced sample size limited the ability to draw definitive conclusions.

Effectiveness and safety of oral anticoagulants in older adults with non-valvular atrial fibrillation and heart failure

Direct oral anticoagulants (DOACs) are at least as efficacious and safe as warfarin among non-valvular atrial fibrillation (NVAF) patients; limited evidence is available regarding NVAF patients with heart failure (HF). US Medicare enrollees with NVAF and HF initiating DOACs (apixaban, rivaroxaban, dabigatran) or warfarin were selected. Propensity score matching and Cox models were used to estimate the risk of stroke/systemic embolism (SE), major bleeding (MB), and major adverse cardiac events (MACE) comparing DOACs versus warfarin and DOACs versus DOACs. We identified 10,570 apixaban-warfarin, 4,297 dabigatran-warfarin, 15,712 rivaroxaban-warfarin, 4,263 apixaban-dabigatran, 10,477 apixaban-rivaroxaban, and 4,297 dabigatran-rivaroxaban matched pairs. Compared to warfarin, apixaban had lower rates of stroke/SE (hazard ratio = 0.64, 95% confidence interval = 0.48-0.85), MB (hazard ratio = 0.66, 0.58-0.76), and MACE (hazard ratio = 0.73,0.67-0.79); dabigatran and rivaroxaban had lower rates of MACE (hazard ratio = 0.87,0.77-0.99; hazard ratio = 0.84, 0.79-0.89, respectively). Rivaroxaban had a lower stroke/SE rate (hazard ratio = 0.65, 0.52-0.81) and higher MB rate (hazard ratio = 1.18, 1.08-1.30) versus warfarin. Compared to dabigatran and rivaroxaban, apixaban had lower MB (hazard ratio = 0.71, 0.57-0.89; hazard ratio = 0.55, 0.49-0.63) and MACE rates (hazard ratio = 0.80, 0.69-0.93; hazard ratio = 0.86, 0.79-0.94), respectively. All DOACs had lower MACE rates versus warfarin; differences were observed in stroke/SE and MB. Our findings provide insights about OAC therapy among NVAF patients with HF.

Comparative safety and effectiveness of direct oral anticoagulants in patients with atrial fibrillation in clinical practice in Scotland

AIMS

The aim of this study was to compare the clinical effectiveness and safety of direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF) in routine clinical practice.

METHODS

This retrospective cohort study used linked administrative data. The study population (n = 14 577) included patients with a diagnosis of AF (confirmed in hospital) who initiated DOAC treatment in Scotland between August 2011 and December 2015. Multivariate Cox proportional hazard models were used to estimate hazard ratios of thromboembolic events, mortality and bleeding events.

RESULTS

No differences between the DOACs were observed with regard to the risk of stroke, systemic embolism or cardiovascular death. In contrast, the risk of myocardial infarction was higher among patients prescribed apixaban in comparison to those on rivaroxaban (HR 1.67, 95% CI 1.02-2.71), and all-cause mortality was higher among rivaroxaban patients in contrast to both apixaban (1.22 [1.01-1.47]) and dabigatran (1.55 [1.16-2.05]) patients; rivaroxaban patients also had a higher risk of pulmonary embolism than apixaban patients (5.27 [1.79-15.53]). The risk of other major bleeds was higher among rivaroxaban patients compared to apixaban (1.50 [1.10-2.03]) and dabigatran (1.58 [1.01-2.48]) patients; the risks of gastrointestinal bleeds and overall bleeding were higher among rivaroxaban patients than among apixaban patients (1.48 [1.01-2.16] and 1.52 [1.21-1.92], respectively).

CONCLUSIONS

All DOACs were similarly effective in preventing strokes and systemic embolisms, while patients being treated with rivaroxaban exhibited the highest bleeding risks. Observed differences in the risks of all-cause mortality, myocardial infarction and pulmonary embolism warrant further research.

Comparative Effectiveness and Safety of Rivaroxaban in Adults With Nonvalvular Atrial Fibrillation

BACKGROUND

All evidence regarding benefits and harms of rivaroxaban for stroke prevention has not been appraised yet.

STUDY QUESTION

What are the comparative effectiveness and safety of rivaroxaban in adults with nonvalvular atrial fibrillation?

DATA SOURCES

Randomized controlled trials (RCTs), meta-analyses, and observational studies were identified in several databases in October 2018.

STUDY DESIGN

Rapid review with evidence appraisal using the Grading of Recommendations Assessment, Development and Evaluation working group approach.

RESULTS

Two direct RCTs (23,021 patients) suggest that rivaroxaban is noninferior to warfarin in the prevention of stroke and systemic embolism (pooled relative risk [RR] 0.73, 95% confidence interval [CI], 0.43-1.24), reduces risk of hemorrhagic stroke (RR 0.59, 95% CI, 0.38-0.92), fatal bleeding (RR 0.49, 95% CI, 0.31-0.76), and cardiac arrest (RR 0.45, 95% CI, 0.25-0.82, 2 RCTs), but increases risk of major gastrointestinal bleeding (RR 1.46, 95% CI, 1.19-1.78). In observational studies, rivaroxaban is associated with lower risk of ischemic stroke (RR 0.87, 95% CI, 0.77-0.99, 222,750 patients), acute myocardial infarction (RR 0.61, 95% CI, 0.48-0.78, 73,739 patients), and intracranial hemorrhage (RR 0.64, 95% CI, 0.45-0.92, 197,506 patients) but higher risk of gastrointestinal bleeding (RR 1.30, 95% CI, 1.19-1.42, 188,968 patients) and higher risk of mortality when compared with warfarin in European studies (RR 1.19, 103,270 patients in the UK; RR 2.02, 22,358 patients in Denmark) but lower risk of mortality in Taiwan (RR 0.58, 40,000 patients). Network meta-analyses and observational studies suggest that rivaroxaban is associated with higher risk of bleeding when compared with apixaban (RR 2.14, 72,586 patients), dabigatran (RR 1.24, 67,102 patients), and edoxaban (RR 1.32, 71,683 patients).

CONCLUSIONS

Research on the long-term comparative effectiveness, safety, and effects on quality of life between rivaroxaban and other novel oral anticoagulants is urgently needed.

Anticoagulation in atrial fibrillation with factor X deficiency-A management dilemma

Factor X (FX) deficiency is a rare bleeding disorder. There is currently no clear guideline or recommendation for the appropriate selection of anticoagulation and management of patients with FX deficiency who require anticoagulation. We shared our experience in managing such patient, and we further discussed other possible treatment options.

Effectiveness and Safety of Direct Oral Anticoagulants and Warfarin, Stratified by Stroke Risk in Patients With Atrial Fibrillation

The objective of the study was to examine how the comparative effectiveness and safety of direct oral anticoagulants (DOACs) and warfarin differ across subgroups of patients with atrial fibrillation defined by stroke risk (CHA2DS2-VASc score ≤3, 4 to 5, ≥6). Using Medicare claims data, we identified patients newly diagnosed with atrial fibrillation in 2013 to 2014 who initiated warfarin (n=12,354), apixaban (n=2,358), dabigatran (n=1,415), or rivaroxaban (n=5,139), and categorized them according to their CHA2DS2-VASc score (≤3, 4 to 5, ≥6). Primary outcomes included the combined risk of ischemic stroke, other thromboembolic event and death, and the risk of bleeding. We constructed Cox proportional hazard models that included terms for treatment, CHA2DS2-VASc subgroup, and the interaction between them, and controlled for demographics and a comprehensive list of clinical characteristics. We found that DOACs were generally more effective than warfarin, but this effect was most pronounced in the lowest risk subgroup. Specifically, the hazard ratio for the primary effectiveness outcome with apixaban compared with warfarin was 0.46 (95% confidence interval [CI] 0.32 to 0.65) for CHA2DS2-VASc ≤3, 0.71 (95% CI 0.61 to 0.86) for 4 to 5, and 0.86 (95% CI 0.74 to 1.01) for ≥6 (p value for interaction = 0.005). The comparative safety profile of DOACs versus warfarin did not change with CHA2DS2-VASc score. In conclusion, DOACs are more effective than warfarin, but this effect is more pronounced in patients with lower risk of stroke. Further research is needed to validate these findings in other patient cohorts and uncover their underlying mechanisms.

Use of Non-Vitamin K Antagonist Oral Anticoagulants 2008-2016: A Danish Nationwide Cohort Study

We aimed to provide detailed utilization data on the total use of non-vitamin K antagonist oral anticoagulants (NOACs) since their introduction in 2008. Using the nationwide Danish National Prescription Registry, we identified all individuals filling prescriptions for NOACs 2008-2016. We reported the development in incident and prevalent users and explored baseline characteristics and treatment persistence according to treatment indication. A total of 126,691 NOAC users were identified within the Danish population of 5.7 million inhabitants. The annual incidence and prevalence increased rapidly reaching 10 and 17 per 1000 individuals in 2016. Patients received NOACs due to atrial fibrillation (AF) (43%), venous thromboembolism (VTE) prophylaxis after arthroplastic surgery (17%), VTE (12%) and no registered indication (28%). The most frequently used NOAC was rivaroxaban (n = 52,431), followed by dabigatran (n = 47,067), apixaban (n = 27,116) and edoxaban (n = 77). The proportion of AF and VTE patients initiating low-dose NOACs were between 23% and 50%. Patients treated with NOAC for VTE primarily received rivaroxaban. We observed a trend towards increased use of apixaban and rivaroxaban at the expense of dabigatran. Treatment persistence was highly dependent on treatment indication. Persistence to NOAC after 3 years was only 62% in AF compared to 28% for VTE. We documented an accelerating increase in the use of all four NOACs in the first 8 years after introduction. We have identified areas requiring further attention, including reasons for missing indications, potential inappropriate dosing and low long-term persistence with NOACs in patients with AF.

Outcomes of Patients With Atrial Fibrillation Newly Recommended for Oral Anticoagulation Under the 2014 American Heart Association/American College of Cardiology/Heart Rhythm Society Guideline

BACKGROUND

In March 2014, the American Heart Association updated their guidelines for the management of oral anticoagulation (OAC) in atrial fibrillation, recommending OAC for all patients with CHA₂DS₂-VASc ≥2. Previously, only patients with CHADS₂ ≥2 were recommended for anticoagulation. This study compared effectiveness and safety outcomes of OAC among patients who would receive OAC using the 2014 guidelines but not the 2011 guidelines.

METHODS AND RESULTS

Using claims data from a 5% sample of 2013-2014 Medicare beneficiaries, we identified patients with initially diagnosed atrial fibrillation between 2013 and 2014 and selected those who would receive OAC under the 2014 guidelines but not the 2011 guidelines (those with CHA₂DS₂-VASc score ≥2 or CHADS₂ score <2). Patients were categorized according to their use of OAC after first atrial fibrillation diagnosis (2937 users and 2914 nonusers). Primary outcomes included the composite of ischemic stroke, systemic embolism and death, and any bleeding event. Cox proportional hazard models were constructed to compare the risk of primary outcomes between the 2 groups, while controlling for patient demographic and clinical characteristics. There was no difference in the combined risk of stroke, systemic embolism, and death between the treatment groups (hazard ratio, 1.00; 95% confidence interval, 0.84-1.20). The risk of bleeding was higher for patients receiving OAC than for patients not receiving OAC (hazard ratio, 1.70, 95% confidence interval, 1.46-1.97).

CONCLUSIONS

The benefit of OAC is not well defined in this patient population, and new studies that minimize residual confounding are needed to fully understand the risk/benefit of OAC in patients with atrial fibrillation and low to moderate stroke risk.