The effectiveness and safety of low-dose rivaroxaban in Asians with non-valvular atrial fibrillation

Low-dose Rivaroxaban: is it a safe alternative in Chinese older patients?

PURPOSE

10 mg rivaroxaban is widely used in the Chinese mainland. This study aims to explore the association between 10 mg once daily rivaroxaban and all-cause mortality in patients with nonvalvular atrial fibrillation (NVAF).

METHODS

This observational study enrolled 1131 NVAF patients at the cardiovascular department of the First Affiliated Hospital of Xi'an Jiaotong University. One-year outcomes included all-cause mortality and bleeding were recorded. Cox proportional hazards models and Kaplan-Meier analysis were utilized in the study.

RESULTS

In total, 1131 patients (402 no anticoagulants, and 729 rivaroxaban) were included. Cox proportional hazard analysis demonstrated that low-dose rivaroxaban (10 mg, HR: 0.14, 95% CI:(0.07-0.28), P<0.001; 15 mg, HR: 0.20, 95% CI:(0.09-0.43), P<0.001; 20 mg, HR: 0.22, 95% CI:(0.05-0.96), P = 0.044) exhibited lower mortality risk compared to untreated patients.

CONCLUSIONS

10 mg once daily rivaroxaban may provide survival benefits for elderly patients with NVAF.

Efficacy and Safety of Different Dosing Regimens of Rivaroxaban in Patients With Atrial Fibrillation for Stroke Prevention: A Systematic Review and Meta-Analysis

Atrial fibrillation (AF) poses a substantial risk of stroke, necessitating effective anticoagulation therapy. This systematic review and meta-analysis (SRMA) evaluates the efficacy and safety of different dosing regimens of rivaroxaban in patients with AF. A comprehensive search of relevant databases, focusing on studies published from 2017 onward, was conducted. Inclusion criteria comprised randomized controlled trials (RCTs) and observational studies comparing standard and reduced dosing of rivaroxaban in AF. Data extraction and risk of bias (ROB) assessment were performed, and a meta-analysis was conducted for relevant outcomes. A total of 21 studies fulfilled the inclusion criteria. Standard dosing demonstrates a slightly lower risk of composite effectiveness outcomes and safety outcomes (HR: 0.79, 95% CI: 0.66-0.94, P=0.01) compared to reduced dosing (HR: 0.83, 95% CI: 0.71-0.97, P=0.02). Notable differences in major bleeding, gastrointestinal bleeding (GIB), and intracranial bleeding favored standard dosing. Hemorrhagic stroke and all-cause stroke rates differed significantly, with standard dosing showing a more favorable profile for ischemic stroke prevention. This study highlights the pivotal role of personalized anticoagulation therapy in AF. Standard dosing of rivaroxaban emerges as a preferred strategy for stroke prevention, balancing efficacy and safety. Clinical decision-making should consider individual patient characteristics and future research should delve into specific subpopulations and long-term outcomes to further refine treatment guidelines. The study bridges evidence from clinical trials to real-world practice, offering insights into the evolving landscape of AF management.

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

OBJECTIVE

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

DESIGN

Pairwise and network meta-analyses.

SETTING AND PARTICIPANTS

Patients with AF aged ≥75 years.

METHODS

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

RESULTS

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

CONCLUSIONS AND IMPLICATIONS

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

Is a Lower Dose of Rivaroxaban Required for Asians? A Systematic Review of a Population Pharmacokinetics and Pharmacodynamics Analysis of Rivaroxaban

Rivaroxaban has been widely used to prevent and treat various thromboembolic diseases for more than a decade. However, whether a lower dose of rivaroxaban is required for Asians is still debatable. This review aimed to explore the potential ethnic difference in pharmacokinetic/pharmacodynamic (PK/PD) characteristics between Asians and Caucasians. A systematic search was conducted and twenty-four studies were identified, of which 10 were conducted on Asian adults, 11 on predominantly Caucasian adults, and 3 on Caucasian pediatrics. The apparent clearance (CL/F) of rivaroxaban in Caucasian adults with non-valvular atrial fibrillation (6.45-7.64 L/h) was about 31-43% higher than that in Asians (4.46-5.98 L/h) taking 10~20 mg rivaroxaban every 24 h. Moreover, there was no obvious difference in CL/F among Japanese, Chinese, Thai, and Irani people. Regarding PK/PD relationship, prothrombin time was linked to rivaroxaban concentration in a linear or near-linear manner, and Factor Xa activity was linked with the E_max model. The exposure-response relationship was comparable between Asians and Caucasians. Renal function has a significant influence on CL/F, and no covariate was recognized for exposure-response relationship. In conclusion, a lower dose of rivaroxaban might be required for Asians, and further studies are warranted to verify this ethnic difference to facilitate optimal dosing regimens.

Population Pharmacokinetics and Hemorrhagic Risk Analysis of Rivaroxaban in Elderly Chinese Patients With Nonvalvular Atrial Fibrillation

Rivaroxaban is a popular direct factor Xa inhibitor used for anticoagulation therapy in patients with nonvalvular atrial fibrillation (NVAF). The aim of this study was to establish a population pharmacokinetic (PPK) model for rivaroxaban in elderly Chinese patients with nonvalvular atrial fibrillation, evaluate precision dosing regimens, and analyze hemorrhagic risk after rivaroxaban treatment. A 1-compartment population PK model with estimated glomerular filtration rate (eGFR), total bilirubin (TBIL), and ABCB1 rs1045642 as major covariates for apparent clearance was developed using the nonlinear mixed-effects model (NONMEM). A Monte Carlo simulation was performed to evaluate various dosing schemes and different levels of covariates for the target range of therapeutic drug-monitoring concentrations (C_max,ss and C_min,ss ). The exposure to rivaroxaban was simulated and assessed through hemorrhagic risk evaluation. The results showed that the average probability of target attainment (PTA) for optimal dosing regimens with different covariate levels for the targeted C_max,ss and C_min,ss were 29.35% to 31.3% and 64.91% to 65.8%, respectively. A dosage of 10 mg of rivaroxaban in elderly Chinese patients with normal renal and liver function was appropriate. The area under the concentration-time curve estimated over 24 hours with precision dosing at steady state (AUC_24,ss ) was statistically significantly associated with an increased risk of bleeding events (OR 1.0006, 95%CI 1.0003 to 1.001, P < .0001), and the bleeding risk increased by 1.82-fold for every 1000 μg*h/L increase in AUC_24,ss . A lower dose is recommended for elderly patients with renal impairment to avoid overexposure and bleeding events. The PPK model could inform individualized dosing for elderly Chinese patients with nonvalvular atrial fibrillation receiving rivaroxaban anticoagulation therapy.

Trough Concentration Deficiency of Rivaroxaban in Patients With Nonvalvular Atrial Fibrillation Leading to Thromboembolism Events

ABSTRACT

This retrospective study investigated factors influencing the steady-state trough concentrations (C trough ) of rivaroxaban in patients with nonvalvular atrial fibrillation (NVAF). We retrieved data from patients with NAVF who first started rivaroxaban anticoagulation at the Fujian Provincial Hospital from October 2017 to October 2020 through the electronic medical record system. Patients were followed for 1 year after the first dose of rivaroxaban, and the primary efficacy and safety end points were recorded. All follow-up visits were completed by October 2021. A C trough of <12 ng/mL was defined as C trough deficiency. Factors that influenced rivaroxaban C trough deficiency were investigated using multivariate binary logistic regression analysis. Kaplan-Meier survival curve analysis was used to determine differences between C trough deficiency and event-free survival. A total of 167 patients with NVAF were enrolled in the study, including 113 men and 54 women, with an average (± SD) age of 70.40 ± 12.46 years. High albumin levels were an independent protective factor against C trough deficiency (odds ratio, 0.932; P = 0.031). C trough deficiency was associated with the probability of freedom from thrombotic events ( P = 0.004); however, there were no significant differences in the probability of freedom from bleeding events ( P > 0.05). In conclusion, among the variables studied, a low albumin level was the main contributor to C trough deficiency. Rivaroxaban C trough deficiency also increased thrombotic events, but this was not associated with hemorrhagic events in Chinese patients with NVAF.

Population pharmacokinetic and pharmacodynamic analysis of rivaroxaban in Chinese patients with non-valvular atrial fibrillation

Rivaroxaban, a direct factor Xa inhibitor, is widely used for stroke prevention in patients with non-valvular atrial fibrillation (NVAF). The aim of this study was to conduct a population pharmacokinetic-pharmacodynamic (PK-PD) analysis of rivaroxaban in Chinese patients with NVAF to assess ethnic differences and provide model-based precision dosing. A total of 256 rivaroxaban plasma concentrations and 244 prothrombin time (PT) measurements were obtained from 195 Chinese NVAF patients from a prospective clinical trial. The population PK-PD model was developed using nonlinear mixed effects modeling (NONMEM) software. The PK of rivaroxaban was adequately described using a one-compartment model with first-order adsorption and elimination. Estimated glomerular filtration rate (eGFR) was identified as a major covariate for apparent clearance. No single nucleotide polymorphism was identified as a significant covariate. PT exhibited a linear relationship with rivaroxaban concentration. Total bilirubin (TBIL) and eGFR were identified as significant covariates for baseline PT. According to the Monte Carlo simulation, 15 mg for Chinese patients with eGFR ≥50 mL/min and normal liver function yielded an exposure comparable to 20 mg for Caucasian patients. Patients with moderately impaired renal function may require a lower dose of rivaroxaban to avoid overexposure. Moreover, there was an approximate 26% increase in PT levels in patients with TBIL of 34 μmol/L and eGFR of 30 mL/min, which could increase the risk of major bleeding. The established population PK-PD model could inform individualized dosing for Chinese NVAF patients who are administered rivaroxaban.

Population Pharmacokinetics and Dose Optimization Based on Renal Function of Rivaroxaban in Thai Patients with Non-Valvular Atrial Fibrillation

Low-dose rivaroxaban has been used in Asian patients with direct oral anticoagulants (DOACs) eligible for atrial fibrillation (AF). However, there are few pharmacokinetic (PK) data in Thai patients to support precise dosing. This study aimed to develop a population PK model and determine the optimal rivaroxaban doses in Thai patients. A total of 240 Anti-Xa levels of rivaroxaban from 60 Thai patients were analyzed. A population PK model was established using the nonlinear mixed-effect modeling approach. Monte Carlo simulations were used to predict drug exposures at a steady state for various dosages. Proportions of patients having rivaroxaban exposure within typical exposure ranges were determined. A one-compartment model with first-order absorption best described the data. Creatinine clearance (CrCl) and body weight significantly affected CL/F and V/F, respectively. Regardless of body weight, a higher proportion of patients with CrCl < 50 mL/min receiving the 10-mg once-daily dose had rivaroxaban exposures within the typical exposure ranges. In contrast, a higher proportion of patients with CrCl ≥ 50 mL/min receiving the 15-mg once-daily dose had rivaroxaban exposures within the typical exposure ranges. The study’s findings suggested that low-dose rivaroxaban would be better suited for Thai patients and suggested adjusting the medication’s dose in accordance with renal function.

XaMINA: A Real-World, Prospective, Observational Study of Treatment-Naïve Patients Treated with Rivaroxaban for Stroke Prevention in Atrial Fibrillation in Asia

INTRODUCTION

The efficacy and safety of rivaroxaban for the prevention of stroke and systemic embolism have been demonstrated in Asian and non-Asian patients with non-valvular atrial fibrillation (NVAF) in multiple studies. However, limited published data exist on its use specifically in treatment-naïve patients from the Asia region. Patients in South Korea and Taiwan can now receive rivaroxaban as first-line therapy, allowing for data generation in this patient group.

METHODS

XaMINA was a prospective, real-world, multicenter, single-arm, observational cohort study of patients with NVAF in South Korea and Taiwan naïve to anticoagulation and initiating rivaroxaban. The primary outcome was major bleeding; secondary outcomes included all-cause mortality, symptomatic thromboembolic events, and treatment persistence.

RESULTS

In total, 1094 patients were included and the follow-up was 1 year. The baseline mean CHADS₂ score was 1.63 ± 0.98, mean CHA₂DS₂-VASc score was 2.92 ± 1.42, and mean HAS-BLED score was 1.00 ± 0.75. The primary outcome occurred in 20 (1.8%) patients [incidence rate 2.1 events per 100 patient-years (95% CI 1.35-3.25)]. Thromboembolic events occurred in 9 (0.8%) patients, of whom 5 (0.5%) had stroke, 3 (0.3%) myocardial infarction, and 1 (0.1%) a transient ischemic attack. There were no cases of non-central nervous system systemic embolism, and 735 (67.2%) patients persisted with rivaroxaban treatment for 1 year.

CONCLUSION

XaMINA demonstrated low incidence rates of major bleeding events and thromboembolic events in patients with NVAF newly initiating rivaroxaban in South Korea and Taiwan, consistent with previous real-world studies reconfirming the results of the ROCKET AF study.

TRIAL REGISTRATION

The trial was registered on ClinicalTrials.gov (identifier NCT03284762) on 15 September 2017.

Real-World Comparisons of Low-Dose NOACs versus Standard-Dose NOACs or Warfarin on Efficacy and Safety in Patients with AF: A Meta-Analysis

Objective

We aimed to further investigate the efficacy and safety of low-dose NOACs by performing a meta-analysis of cohort studies.

Background

Meta-analyses of randomized controlled trials (RCTs) have demonstrated that low-dose non-vitamin K antagonist oral anticoagulants (NOACs) showed inferior efficacy compared with standard-dose NOACs, although they are still frequently prescribed for patients with atrial fibrillation (AF) in the clinical practice.

Methods

Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and MEDLINE were systematically searched from the inception to September 9, 2021, for cohort studies that compared the efficacy and/or safety of low-dose NOACs in patients with AF. The primary outcomes were ischemic stroke and major bleeding, and the secondary outcomes were mortality, intracranial hemorrhage (ICH), and gastrointestinal hemorrhage (GH). Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated with the random-effect model.

Results

Twenty-five publications involving 487856 patients with AF were included. Compared with standard-dose NOACs, low-dose NOACs had comparable risks of ischemic stroke (HR = 1.03, 95% CI 0.96 to 1.11), major bleeding (HR = 1.12, 95% CI 0.97 to 1.28), ICH (HR = 1.09, 95% CI 0.88 to 1.36), and GH (HR = 1.11, 95% CI 0.92 to 1.33), except for a higher risk of mortality (HR = 1.41, 95% CI 1.21 to 1.65). Compared with warfarin, low-dose NOACs were associated with lower risks of ischemic stroke (HR = 0.72, 95% CI .67 to 0.78), mortality (HR = 0.67, 95% CI 0.59 to 0.77), major bleeding (HR = 0.64, 95% CI 0.53 to 0.79), ICH (HR = 0.57, 95% CI 0.42 to 0.77), and GH (HR = 0.78, 95% CI 0.64 to 0.95).

Conclusions

Low-dose NOACs were comparable to standard-dose NOACs considering risks of ischemic stroke, major bleeding, ICH, and GH, and they were superior to warfarin. Low-dose NOACs might be prescribed effectively and safely for patients with AF. Considering limitations, further well-designed prospective studies are foreseen.

Standard- vs. low-dose rivaroxaban in patients with atrial fibrillation: a systematic review and meta-analysis

PURPOSE

Low-dose rivaroxaban is often given to patients with atrial fibrillation (AF) around the world, but the rationale for its use remains unclear. We aimed to compare the efficacy and safety of standard- or low-dose rivaroxaban in patients with AF through systematic review of literature with meta-analysis.

METHODS

We searched PubMed, Web of Science, EMBASE, Clinical Trials.gov, the Cochrane Library, and Bayer trial website from inception of each database until June 2020. Randomized controlled trials (RCTs) and cohort studies were included in the meta-analysis. A random-effects model was employed to calculate the pooled effect estimates.

RESULTS

Two RCTs and 17 cohort studies were included in the qualitative analysis. Indirect comparison of RCTs showed no significant difference between the two rivaroxaban dosages in risk of efficacy or safety outcomes (p > 0.05). Indirect comparison of cohort studies showed a lower risk of MACE among Caucasians in standard-dose group (HR 0.779; 95% CI 0.687-0.884; p < 0.001). Bleeding outcomes did not differ significantly between the two dosage regimens in Asian or Caucasian populations, except that the standard dose was associated with higher risk of major bleeding among elderly Caucasian patients (HR 1.329; 95% CI 1.141-1.547; p < 0.001). The quality of evidence was rated ranging from very low to low for all the efficacy and safety outcomes.

CONCLUSION

In Caucasians with AF, standard-dose rivaroxaban may prevent MACE significantly better than low-dose treatment. Further studies in Asians are needed to verify the advantages of the standard dose.

Safety and Effectiveness of Rivaroxaban in Combination with Various Antiarrhythmic Drugs in Patients with Non-Permanent Atrial Fibrillation

INTRODUCTION

Rivaroxaban reduces the risk of thromboembolism in atrial fibrillation (AF) patients, who often also receive antiarrhythmic drugs (AADs) to maintain sinus rhythm. Current guidelines contraindicate concomitant use of rivaroxaban with the popular AAD dronedarone, despite little data demonstrating interactions with AADs. This study investigates the outcomes of concomitant rivaroxaban and AAD drug use in a real-world cohort.

METHODS

This retrospective study included 1777 non-permanent AF patients taking rivaroxaban for ≥ 1 month between 2011 and 2016 from a multicenter cohort in Taiwan, and compared concomitant AAD use against clinical outcome endpoints for safety, effectiveness, and major adverse cardiac events (MACE). Multivariate Cox proportional hazard analyses were used to evaluate the association between concomitant AAD use and outcomes.

RESULTS

Patients were divided into rivaroxaban alone (n = 1205) and with concomitant amiodarone (n = 177), dronedarone (n = 231), or propafenone (n = 164) groups. The proportion of patients using rivaroxaban 10 mg was highest in the concomitant dronedarone group: rivaroxaban alone, 53.6%; with amiodarone, 57.6%; with dronedarone, 77.1%; and with propafenone, 46.3% (p < 0.001). The cumulative incidences of safety (p = 0.892), effectiveness (p = 0.336), and MACE (p = 0.674) were similar between the four groups; however, there were significantly fewer new systemic thromboembolisms in the dronedarone group: rivaroxaban alone, 2.5%; with amiodarone, 0.6%; with dronedarone, 0%; and with propafenone, 1.2% (p = 0.029). The all-cause death rate was also lowest in the dronedarone group: rivaroxaban alone, 9.0%; with amiodarone, 9.6%; with dronedarone, 3.0%; and with propafenone: 6.1% (p = 0.013). After covariate adjustment, there were no differences in the safety, effectiveness, and MACE endpoints between patients receiving or not receiving AADs.

CONCLUSION

Concomitant use of rivaroxaban with AADs appears to be well tolerated, warranting further investigation into the apparent benefits of a reduced dose of rivaroxaban combined with dronedarone.

Off-label reduced-dose apixaban does not reduce hemorrhagic risk in Taiwanese patients with nonvalvular atrial fibrillation: A retrospective, observational study

ABSTRACT

East Asians are reportedly at high risk of anticoagulant-related bleeding; therefore, some physicians prefer to prescribe low-dose direct oral anticoagulants (DOACs). Little is known about the therapeutic effectiveness and safety of off-label reduced-dose apixaban in East Asians with nonvalvular atrial fibrillation (AF). We aimed to investigate the effectiveness and safety of off-label reduced-dose apixaban in Taiwanese patients with nonvalvular AF.This retrospective cohort study enrolled 1073 patients with nonvalvular AF who took apixaban between July 2014 and October 2018 from 4 medical centers in southern Taiwan. The primary outcomes included thromboembolic events (stroke/transient ischemic attack or systemic embolism), major bleeding, and all-cause mortality.Among all patients, 826 (77%) patients were classified as the "per-label adequate-dose" treatment group (i.e., consistent with the Food and Drug Administration label recommendations) while 247 (23%) patients were the "off-label reduced-dose" treatment group. The mean follow-up period was 17.5 ± 13 months. The "off-label reduced-dose" group did not have a lower major bleeding rate than the "per-label adequate-dose" group (4.8% vs 3.8%, adjusted hazard ratio [HR] 1.20, 95% confidence interval [CI] 0.69-2.09), but had a nonsignificantly higher incidence of thromboembolic events (4.23% vs 3.05%, adjusted HR: 1.29, 95% CI: 0.71-2.34).An off-label reduced-dose apixaban treatment strategy may not provide incremental benefits or safety for Taiwanese patients with nonvalvular AF.

Benefits and Harms of Low-Dose Rivaroxaban in Asian Patients With Atrial Fibrillation: A Systematic Review and Meta-analysis of Real-World Studies

Background: Low-dose prescription of rivaroxaban was common among patients with atrial fibrillation (AF) in Asia. However, the benefits and harms of rivaroxaban at a low dosage in Asian patients with AF remains unclear. Accordingly, we aimed to collect and summarize all available evidence to fill this important knowledge gap. Methods: In this systematic review and meta-analysis, we systematically searched databases of MEDLINE, EMBASE, and Cochrane Library for relevant studies from inception until February 23, 2021. Eligible retrospective nationwide or health insurance database studies or prospective registration studies that reported efficacy (stroke/systemic embolism), safety (major bleeding, intracranial hemorrhage, gastrointestinal bleeding), or other outcomes (myocardial infarction, death) of low-dose rivaroxaban in comparison with warfarin in AF patients were enrolled. Data extraction and study quality assessment were conducted by two authors independently. Low dosing of rivaroxaban (15/10 mg) was defined as the received dose lower than the recommended dose (20 mg) approved in most districts. Hazard ratio (HR) with 95% confidence intervals (95% CIs) was pooled using a random-effect model. Subgroup analyses were conducted according to different dose regimens. Sensitivity analyses were conducted by sequential elimination of each study from the pool. Since potential effect modifiers (patient demographics, differences of each study, and others) may lead to bias in primacy outcomes, we performed a meta-regression analysis to explore the influence of these factors on the primary efficacy and safety outcomes. Results: Totally, 12 studies involving 292,815 Asian patients with AF were included. All studies were detected as low to moderate risk bias. Low-dose rivaroxaban treatment in Asian AF patients was associated with a reduced risk of stroke/systemic embolism (HR: 0.76, 95% CI: 0.70-0.84, I ² : 57.8%), major bleeding (HR: 0.72, 95% CI: 0.62-0.84, I ² : 81.5%), and all-cause death (HR: 0.65, 95% CI: 0.58-0.73, I ² : 81.7%) when compared with warfarin. Furthermore, consistent results were observed among different dose regimens (10/15/20 mg) in all the clinical outcomes (P _interaction > 0.05 for each outcome). Meta-regression analysis failed to detect any potential confounding to impact the primacy outcomes. Conclusion: Insights from the present meta-analysis, we found that low-dose rivaroxaban, even at a dosage of 10 mg daily, was associated with a reduced risk of stroke/SE and bleeding than warfarin in Asian AF patients. However, owing to considerable heterogeneity among included studies, further prospective studies are required to confirm these findings.

Dose specific effectiveness and safety of DOACs in patients with non-valvular atrial fibrillation: A Canadian retrospective cohort study

BACKGROUND

Direct oral anticoagulants (DOACs) have been proven to be effective and safe for prevention of ischemic stroke and systemic embolism in patients with non-valvular atrial fibrillation (NVAF). However, suboptimal adherence, variable dosing and use in patient populations that otherwise would have been excluded from clinical trials may impact the efficacy and safety profile of DOACs in a routine care setting. We compared stroke, bleeding, and mortality rates on and off therapy for standard and low-dose DOACs (apixaban, rivaroxaban, dabigatran) versus warfarin in a Canadian cohort. We also assessed persistence of DOACs compared to warfarin.

METHODS

We conducted six 1-1 propensity-score matched retrospective cohort analyses using Quebec health administrative databases (2011-2017). NVAF patients (≥18 years) covered by the public medication insurance plan entered the cohort on the first OAC dispensation date. We excluded those with OAC use in the previous year or stroke or bleeding diagnoses in the previous two years. Follow-up ended at death, March 2017 or end of medication coverage by the public plan. Time-dependent Cox regression was applied.

RESULTS

We evaluated 10,893 patients initiated on apixaban (7206 standard, 3687 low-dose), 10,190 on rivaroxaban (7396 standard, 2794 low-dose), 5884 on dabigatran (2756 standard, 3128 low-dose), and propensity score-matched warfarin users. Across standard-dose DOACs, compared to warfarin, stroke risks were similar; bleeding risks were lower with apixaban (hazard ratio 0.63; 95% confidence interval 0.52-0.77) and dabigatran (0.47; 0.35-0.64) but not rivaroxaban (0.93; 0.79-1.10); death risks were lower with all DOACs. For low-dose DOACs, rivaroxaban demonstrated higher stroke (1.79; 1.21-2.64) and bleeding risks (1.37; 1.09-1.73); other agents had stroke risks similar to warfarin and bleeding risks lower than warfarin; only low-dose dabigatran had lower death risk (0.59; 0.52-0.68). Treatment discontinuation was lower with DOACs versus warfarin with the exception of low-dose rivaroxaban. The risks of stroke were 2-4 folds higher during time off any OAC versus time on warfarin. The risks of death were higher, while the risks of bleeding were generally lower during times off any OAC.

CONCLUSIONS

Standard-dose DOACs had similar stroke, better persistence and mortality profiles than warfarin. Only standard dose apixaban and dabigatran had better bleeding profiles than warfarin. Low-dose rivaroxaban had worse persistence, stroke and bleeding profiles than warfarin, while low-dose apixaban and dabigatran had similar stroke and better bleeding profiles. Real-world use of DOACs may explain some of the differences observed in Canadian routine care versus the phase III clinical trials.

The Risk of Gastrointestinal Bleeding between Non-Vitamin K Antagonist Oral Anticoagulants and Vitamin K Antagonists in the Asian Atrial Fibrillation Patients: A Meta-Analysis

Background: Non-vitamin K antagonist oral anticoagulants (NOACs) are more commonly used to prevent atrial fibrillation (AF) patients from thromboembolic events than vitamin K antagonists (VKAs). However, the gastrointestinal bleeding (GIB) risk in the Asian AF patients associated with NOACs in comparison with VKAs remained unaddressed. Materials and Methods: A systematic search of studies on NOACs and VKAs in the Asian AF patients was conducted in PubMed, Cochrane Library, and ClinicalTrials.gov. The primary outcome was the hazard ratio (HR) of any GIB associated with NOACs versus VKAs. The secondary outcome was the GIB risks in different kinds of NOACs compared with VKAs. Results: This meta-analysis included two randomized controlled trials (RCTs) and four retrospective studies, comprising at least 200,000 patients in total. A significantly lower HR of GIB risks was found in all kinds of NOACs than VKAs in the Asian AF patients (HR: 0.633; 95% confidence interval: 0.535-0.748; p < 0.001). Additionally, the GIB risks of different NOACs were apixaban (HR: 0.392), edoxaban (HR: 0.603), dabigatran (HR: 0.685), and rivaroxaban (HR: 0.794), respectively. Conclusions: NOACs significantly reduced the risk of GIB in the Asian AF patients compared with VKAs. In the four NOACs compared with VKAs, apixaban probably had a trend of the least GIB risk. We need further head-to-head studies of different NOACs to confirm which NOAC is the most suitable for Asian AF patients and to know the optimal dosage regimen of different NOACs.

Newer and Better? Comparing Direct Oral Anticoagulants to Warfarin in Patients With Traumatic Intracranial Hemorrhage

BACKGROUND

Direct oral anticoagulants (DOACs) have overtaken warfarin as the preferred anticoagulants for stroke prevention with atrial fibrillation and for treatment of venous thromboembolism. Despite the increased prevalence of DOACs, literature studying their impact on trauma patients with intracranial hemorrhage (ICH) remains limited. Most DOAC reversal agents have only been recently available, and concerns for worse outcomes with DOACs among this population remain. This study aims to assess the outcomes of patients with traumatic ICH taking DOACs compared with those taking warfarin.

METHODS

A retrospective analysis of patients with traumatic ICH over a 5-year period was conducted. Demographics, injury severity, medication, and outcome data were collected for each patient. Patients taking warfarin and DOACs were compared.

RESULTS

736 patients had traumatic ICH over the study period, 75 of which were on either DOACs (25 patients) or warfarin (50 patients). The median age of the anticoagulated patients was 78 years; 52% were female, and 91% presented secondary to a fall. DOACs were reversed at close to half the rate of warfarin (40% vs 77%; P = .032). Despite this, the 2 groups had similar rates of worsening examination, need for operative intervention, and in-hospital mortality. In the follow-up, fewer patients taking DOACs had died at 6-months postinjury compared with those taking warfarin (8% vs 30%; P = .041).

DISCUSSION

Despite DOACs being reversed at nearly half the rate of warfarin, patients presenting with traumatic ICH on warfarin had higher 6-month mortality suggesting a potential survival advantage for DOACs over warfarin in this population.

Reduction in the Doses of Direct Oral Anticoagulants and Risk of Ischemic Stroke Events: A Hospital Survey

Inappropriately reduced doses (IRDs) of direct oral anticoagulants (DOACs) are common in clinical practice. We performed a retrospective review using electronic medical records of St. Marianna University School of Medicine Hospital (a 1200-bed teaching hospital in Japan) to address the prevalence of IRDs and patient-related factors that result in IRDs. We also surveyed DOAC-treated patients who were hospitalized due to a stroke during the 5-year study period to analyze the association between stroke events and IRDs. We found that one in five patients who were newly prescribed a DOAC was treated with IRDs. Patients treated with edoxaban received the most IRDs (64%, 7/11), followed by those treated with dabigatran (50%, 1/2), apixaban (32%, 19/61), and rivaroxaban (27%, 12/44). Our analysis showed that the renal function (measured as serum creatinine and creatinine clearance values) and age are possible factors influencing dose reduction. The HAS-BLED score and antiplatelet use were not associated with IRD prescription. An analysis of the 5-year hospital records revealed 20 stroke cases despite ongoing treatments with DOACs, and IRDs were noted in three of these cases. In all three cases, the patients had been on an IRD of rivaroxaban. To prevent IRDs of DOACs, we suggest that a clinical protocol be incorporated into formularies to support the prescription process.

Risk of Major Gastrointestinal Bleeding With New vs Conventional Oral Anticoagulants: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

There is controversy over whether use of non-vitamin K antagonist oral anticoagulants (NOACs) associates with increased risk of major gastrointestinal bleeding (GIB) compared with conventional therapies (such as vitamin K antagonists or anti-platelet agents). We performed a systematic review and meta-analysis of data from randomized controlled trials and high-quality real-world studies.

METHODS

We performed a systematic search of the MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov Website databases (through Oct 12, 2018) for randomized controlled trials and high-quality real-world studies that reported major GIB events in patients given NOACs or conventional therapy. Relative risks (RRs) for randomized controlled trials and adjusted hazard ratios (aHRs) for real-world studies were calculated separately using random-effects models.

RESULTS

We analyzed data from 43 randomized controlled trials (183,752 patients) and 41 real-world studies (1,879,428 patients). The pooled major rates of GIB for patients on NOACs (1.19%) vs conventional treatment (0.92%) did not differ significantly (RR from randomized controlled trials, 1.09; 95% CI, 0.91-1.31 and aHR from real-world studies, 1.02; 95% CI, 0.94-1.10; P_interaction=.52). Rivaroxaban, but not other NOACs, was associated with an increased risk for major GIB (RR from randomized controlled trials, 1.39; 95% CI, 1.17-1.65 and aHR from real-world studies, 1.14; 95% CI, 1.04-1.23; P_interaction = .06). Analyses of subgroups, such as patients with different indications, dosage, or follow-up time, did not significantly affect results. Meta-regression analysis failed to detect any potential confounding to impact the primacy outcome.

CONCLUSIONS

In a systematic review and meta-analysis of data from randomized controlled trials and real-world studies, we confirmed that there is no significant difference in risk of major GIB between patients receiving NOACs vs conventional treatment. Rivaroxaban users had a 39% increase in risk for major GIB.

Comparisons of Rivaroxaban Following Different Dosage Criteria (ROCKET AF or J-ROCKET AF Trials) in Asian Patients With Atrial Fibrillation

Background

The ROCKET AF (Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation) evaluated rivaroxaban (20/15 mg/d) versus warfarin in patients with atrial fibrillation. A separate trial, J‐ROCKET AF (Japanese ROCKET AF), compared rivaroxaban (15/10 mg/d) and warfarin in Japanese patients with atrial fibrillation. Data about rivaroxaban following J‐ROCKET AF criteria compared with warfarin and ROCKET AF dosage were limited.

Methods and Results

This retrospective study used medical data from a multicenter healthcare provider in Taiwan that included 3162 patients taking rivaroxaban. Among 2320 patients with an estimated glomerular filtration rate (eGFR) ≥50 mL/min per 1.73 m², 384 and 1936 patients followed the ROCKET AF (20 mg/d) and J‐ROCKET AF (15 mg/d) recommendation, respectively. Among 842 patients with an eGFR <50 mL/min per 1.73 m², 422 and 420 patients followed the ROCKET AF (15 mg/d) and J‐ROCKET AF (10 mg/d) recommendation, respectively. A total of 2053 patients with atrial fibrillation receiving warfarin were identified. Rivaroxaban following either ROCKET AF or J‐ROCKET AF dosage criteria was associated with a comparable risk of thromboembolism but a lower risk of bleeding than warfarin. For patients with an eGFR ≥50 mL/min per 1.73 m², risks of clinical events did not differ significantly between the 2 dosage criteria of rivaroxaban. For patients with an eGFR <50 mL/min per 1.73 m², the ROCKET AF dosage was associated with a higher risk of major bleeding compared with the J‐ROCKET AF dosage (hazard ratio, 2.70; P=0.0445) without significant differences regarding the risk of ischemic events.

Conclusions

In Asian patients with atrial fibrillation, the J‐ROCKET AF dosage was as effective as the ROCKET AF dosage irrespective of renal function. The risk of major bleeding was lower with the J‐ROCKET AF dosage in patients with an eGFR <50 mL/min per 1.73 m². Compared with warfarin, rivaroxaban following either dosage criteria was effective and even safer.

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.

WITHDRAWN: Effectiveness and safety of long-term dabigatran among patients with non-valvular atrial fibrillation in clinical practice: J-Dabigatran Surveillance

The Publisher regrets that this article is an accidental duplication of an article that has already been published in Journal of Cardiology, 73/6 (2018) 507–514, https://doi.org/10.1016/j.jjcc.2018.12.013. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal

Effectiveness and safety of long-term dabigatran among patients with non-valvular atrial fibrillation in clinical practice: J-dabigatran surveillance

BACKGROUND

The effectiveness and safety of dabigatran etexilate (DE) have not been elucidated thoroughly in clinical practice for Japanese patients with non-valvular atrial fibrillation (NVAF). In particular, those of DE at a reduced dose due to dose reduction recommendations (DRR) remain unknown.

METHODS

NVAF patients who had newly initiated DE treatment for prevention of thromboembolic events between December 2011 and November 2013 were enrolled. They were followed until August 2016. Outcome events included thromboembolism, major bleeding, and all-cause death.

RESULTS

The study group consisted of 6443 patients (mean age, 70.9 years; male, 66.9%; and mean CHADS₂ score, 1.8). During a follow-up period of 610 days (median), stroke, transient ischemic attack (TIA), and systemic embolism (SE) occurred at 1.4%/year for DE 110mg twice daily (BID) (DE220, n=4759) and 0.8% for dabigatran 150mg BID (DE300, n=1571, unadjusted p=0.0317). Major bleeding occurred at 1.3 and 0.6%/year for DE220 and DE300, respectively (unadjusted p=0.0097). All-cause death occurred at 1.5 and 0.5%/year for DE220 and DE300, respectively (unadjusted p=0.0005). When patients were divided into four groups based on DRR and DE doses (DE300 groups meeting and not meeting DRR, and DE220 groups meeting and not meeting DRR), incidence rates of stroke/TIA/SE and major bleeding differed among the four groups (unadjusted p=0.0026 and 0.0194 for trend, respectively); DE220 group meeting DRR had the highest rates (1.7% and 1.4%/year, respectively). However, in multivariate analysis, no differences between doses were observed regarding any outcomes.

CONCLUSIONS

The present results are indicative of the favorable benefit-risk profile of dabigatran in Japanese clinical practice. Dabigatran dose was not independently associated with thromboembolic and bleeding events in Japanese NVAF patients.

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.