Bleeding risk of apixaban, dabigatran, and low-dose rivaroxaban compared with warfarin in Japanese patients with non-valvular atrial fibrillation: a propensity matched analysis of administrative claims data

A real-world study of different doses of rivaroxaban in patients with nonvalvular atrial fibrillation

To explore the anticoagulant effect and safety of utilizing different doses of rivaroxaban for the treatment of patients with atrial fibrillation (AF) in the real world. A retrospective case-control analysis was performed by applying the hospital database, and 3595 patients with non-valvular atrial fibrillation (NVAF) who were hospitalized and taking rivaroxaban at Wuhan Asia Heart Hospital and Wuhan Asia General Hospital from March 2018 to December 2021 were included in the study, and were divided into the rivaroxaban 10 mg and 15 mg groups according to the daily prescribed dose, of which 443 cases were in the 10 mg group and 3152 cases were in the 15 mg group. The patients were followed up regularly, and the incidence of thrombotic events, bleeding events and all-cause deaths were recorded and compared between the 2 groups, and logistic regression was applied to analyze the influencing factors for the occurrence of adverse events. Comparison of the incidence of thrombosis, bleeding and all-cause death between the 2 groups of patients showed that the 10 mg group was higher than the 15 mg group, but the difference was not statistically significant (χ2 = 0.36, 3.26, 1.99, all P > .05); the incidence of total adverse events between the 2 groups of patients was higher in the 10 mg group than in the 15 mg group, with a statistically significant difference (χ2 = 4.53, P = .033); multifactorial logistic regression results showed that age [OR (95% CI) = 1.02 (1.00-1.04)], diabetes mellitus [OR (95% CI) = 1.69 (1.09-2.62)], D-dimer level [OR (95% CI) = 1.06 (1.00-1.11)] and persistent AF [OR (95% CI) = 1.54 (1.03-2.31)] were risk factors for adverse events (P < .05). In the real world, Asian clinicians recommend rivaroxaban 10 mg once daily for NVAF patients for a variety of reasons; however, this dose is not superior or even inferior to the 15 mg group in terms of effectiveness and safety. Advanced age, elevated D-dimer levels, history of diabetes mellitus, and persistent AF are risk factors for adverse events, and the optimal dosage of rivaroxaban or optimal anticoagulation strategy for Asian patients with nonvalvular AF requires further study.

Heterogeneity after harmonisation: A retrospective cohort study of bleeding and stroke risk after the introduction of direct oral anticoagulants in four Western European countries

PURPOSE

Database heterogeneity can impact effect estimates. Harmonisation provided by common protocols and common data models (CDMs) can increase the validity of pharmacoepidemiologic research. In a case study measuring the changes in the safety and effectiveness of stroke prevention therapy after the introduction of direct oral anticoagulants (DOACs), we performed an international comparison.

METHODS

Using data from Stockholm, Denmark, Scotland and Norway, harmonised with a common protocol and CDM, two calendar-based cohorts were created: 2012 and 2017. Patients with a diagnosis code of atrial fibrillation 5 years preceding the 1-year cohort window were included. DOAC, vitamin K antagonist and aspirin treatment were assessed in the 6 months prior to the start of each year while strokes and bleeds were assessed during the year. A Poisson regression generated incidence rate ratios (IRRs) to compare outcomes from 2017 to 2012 adjusted for changes in individual-level baseline characteristics.

RESULTS

In 280 359 patients in the 2012 cohort and 356 779 in the 2017 cohort, treatment with OACs increased on average from 45% to 65%, while treatment with aspirin decreased from 30% to 10%. In all countries except Scotland, there were decreases in the risk of stroke and no changes in bleeding risk, after adjustment for changes in baseline characteristics. In Scotland, major bleeding (IRR 1.09, 95% confidence interval [CI] [1.00; 1.18]) and intracranial haemorrhage (IRR 1.31, 95% CI [1.13; 1.52]) increased from 2012 to 2017.

CONCLUSIONS

Stroke prevention therapy improved from 2012 to 2017 with a corresponding reduction in stroke risk without increasing the risk of bleeding in all countries, except Scotland. The heterogeneity that remains after methodological harmonisation can be informative of the underlying population and database.

Real-world comparison of in-hospital complications after catheter ablation for atrial fibrillation between non-antivitamin K anticoagulants and warfarin: A propensity-matched analysis using nation-wide database

Background

Few large-scale, real-world studies have compared the efficacy and safety of non-antivitamin K anticoagulants (NOACs) with that of warfarin in catheter ablation (CA) for atrial fibrillation (AF).

Methods

This retrospective, cross-sectional study used a nationwide administrative claims database, to compare complication-incidence rates following CA for AF between NOAC-treated patients and warfarin-treated matched cohorts in the real-world. Among the 32,797,540 records between June 2011 and August 2020 from 426 hospitals, 41,347 patients (38,065 on NOACs and 3,282 on Warfarin) were considered eligible. After performing propensity matching, 6,564 patients (3,282 per group) were analyzed.

Results

The overall complication incidence was significantly lower in the NOACs group than in the warfarin group (2.3 % vs. 4.0 %; P < 0.001, odds ratio [OR]: 0.55, 95 % confidence interval [CI]: 0.41-0.74). Although no significant differences in the incidence of cardiac tamponade (1.0 % vs. 1.1 %; P = 0.90, OR: 0.97, 95 % CI: 0.60-1.56) and major bleeding (0.6 % vs. 0.7 %; P = 0.54, OR: 0.83, 95 % CI: 0.44-1.52) were noted, blood transfusion requirements (0.6 % vs. 1.2 %; P = 0.02, OR: 0.52, 95 % CI: 0.30-0.88) and vascular complications (0.2 % vs. 0.5 %; P = 0.02, OR: 0.33, 95 % CI: 0.12-0.79) were significantly lower in the NOACs group than in the warfarin group. Furthermore, the thromboembolic event incidence was significantly lower in the NOACs group than in the warfarin group (0.5 % vs. 1.2 %; P < 0.001, OR: 0.36, 95 % CI: 0.19-0.64).

Conclusions

NOACs should be considered as a first-line therapy for periprocedural anticoagulation in patients undergoing CA for AF.

Effectiveness and Safety of DOACs in Atrial Fibrillation Patients Undergoing Catheter Ablation: Results from the China Atrial Fibrillation (China-AF) Registry

BACKGROUND

Direct oral anticoagulants (DOACs) have increasingly become an alternative to warfarin in atrial fibrillation (AF) patients. Nonetheless, data on the effectiveness and safety of DOACs in periprocedural of catheter ablation (CA) in real-world practice was relatively rare.

METHODS AND RESULTS

3385 AF patients underwent initial CA and never used oral anticoagulant before enrollment between April 2013 and December 2018 were involved from China Atrial Fibrillation (China-AF) Registry. Warfarin, rivaroxaban and dabigatran were used in 1896 (56.0%), 718 (21.2%), and 771 (22.8%) patients, respectively. Propensity score matching was used to balance covariates across study groups. No significant differences were observed in rivaroxaban-warfarin, dabigatran-warfarin and dabigatran-rivaroxaban cohort for thromboembolic (TE) and major bleeding (MB) incidence. Similar results were also revealed in low-dose rivaroxaban (R_LD)-warfarin, low-dose dabigatran (D_LD)-warfarin and D_LD-R_LD cohort. However, the risk of non-MB was higher not only on standard-dose of rivaroxaban but also on R_LD when compared with warfarin and with D_LD, respectively.

CONCLUSIONS

In this study, the incidence of TE and MB were both comparable in standard- or low-dose DOACs versus warfarin and between the two DOACs, whereas the risk of non-MB was higher in rivaroxaban than in warfarin and in R_LD than in D_LD.

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.

Effectiveness and Safety of Apixaban in over 3.9 Million People with Atrial Fibrillation: A Systematic Review and Meta-Analysis

Background: There is a plethora of real-world data on the safety and effectiveness of direct-acting oral anticoagulants (DOACs); however, study heterogeneity has contributed to inconsistent findings. We compared the effectiveness and safety of apixaban with those of other direct-acting oral anticoagulants (DOACs) and vitamin K antagonists (VKA e.g., warfarin). Methods: A systematic review and meta-analysis was conducted retrieving data from PubMed, SCOPUS and Web of Science from January 2009 to December 2021. Studies that evaluated apixaban (intervention) prescribed for adults (aged 18 years or older) with AF for stroke prevention compared to other DOACs or VKAs were identified. Primary outcomes included stroke/systemic embolism (SE), all-cause mortality, and major bleeding. Secondary outcomes were intracranial haemorrhage (ICH) and ischaemic stroke. Randomised controlled trials and non-randomised trials were considered for inclusion. Results: In total, 67 studies were included, and 38 studies were meta-analysed. Participants taking apixaban had significantly lower stroke/SE compared to patients taking VKAs (relative risk (RR) 0.77, 95% confidence interval (CI) 0.64–0.93, I² = 94%) and dabigatran (RR 0.84, 95% CI 0.74–0.95, I² = 66%), but not to patients administered rivaroxaban. There was no statistical difference in mortality between apixaban and VKAs or apixaban and dabigatran. Compared to patients administered rivaroxaban, participants taking apixaban had lower mortality rates (RR 0.83, 95% CI 0.71–0.96, I² = 96%). Apixaban was associated with a significantly lower risk of major bleeding compared to VKAs (RR 0.58, 95% CI 0.52–0.65, I² = 90%), dabigatran (RR 0.79, 95% CI 0.70–0.88, I² = 78%) and rivaroxaban (RR 0.61, 95% CI 0.53–0.70, I² = 87%). Conclusions: Apixaban was associated with a better overall safety and effectiveness profile compared to VKAs and other DOACs.

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.

Association of Direct Oral Anticoagulants (DOACs) and Warfarin With Haemorrhagic Risk by Applying Correspondence Analysis to Data From the Italian Pharmacovigilance Database - A Case Study

Introduction: Post-marketing data on the risks associated with direct oral anticoagulants (DOACs) are conflicting and only few studies evaluated a comparison between each different DOAC. Real-world data from pharmacovigilance databases can help to better define the safety profile of each DOAC and warfarin. However, Correspondence Analysis (CA) could represent a useful tool in this context. Objective: In the attempt to assess the usefulness of CA as a signal detection pharmacovigilance tool, we applied this method to the Italian Pharmacovigilance Database (RNF, Rete Nazionale di Farmacovigilanza), by comparing with disproportionality analysis on warfarin and DOACs. Methods: Study based on AEs sent to RNF by Campania Region from 2008 to 2021, in which warfarin, dabigatran, apixaban, edoxaban or rivaroxaban were reported as suspected drug. AEs were clustered into three Standardized MedDRA Queries (SMQs): Central Nervous System Haemorrhages and Conditions (CNSH), GastroIntestinal Perforation, Ulceration, Obstruction or Haemorrhages (GIPUOH) and other Haemorrhages (HH). Non-haemorrhagic AEs were included in a fourth cluster (nHH). Results: We retrieved 1,161 reports: 41.5% are associated to warfarin, 21.0% to dabigatran, 17.8% to rivaroxaban, 13.9% to apixaban and 5.8% to edoxaban. No significant differences in age distribution were observed. Results of CA showed that dabigatran and warfarin have the highest contribution (44.910 and 47.656, respectively) to the inertia of Dimension 1 as well as apixaban and dabigatran to the inertia of Dimension 2 (53.768 and 30.488, respectively). Edoxaban and rivaroxaban showed a negligible total contribution. CA biplot showed positive associations between warfarin and HH, apixaban and CNSH and dabigatran and nHH. Conclusion: Results seem to confirm that DOACs are not interchangeable. Apixaban was surprisingly associated with a higher risk of cerebral haemorrhage. As expected, our data support the better safety profile of DOACs than warfarin in terms of skin and respiratory tract hemorrhagic risks. Finally, we showed how CA could play a complementary role in analyzing data from pharmacovigilance databases.

Comparative Safety and Effectiveness of Apixaban vs. Warfarin in Oral Anticoagulant-Naïve Japanese Patients With Non-Valvular Atrial Fibrillation - A Retrospective Chart Review Study

BACKGROUND

The risk of bleeding and stroke/systemic embolism (SE) events associated with apixaban vs. warfarin among oral anticoagulant-naïve Japanese patients with non-valvular atrial fibrillation (NVAF) has not been well studied in daily clinical practice.Methods and Results:Clinical data for 12,090 patients were retrospectively extracted from the medical records of patients with NVAF (aged ≥20 years, creatinine clearance [CrCl] ≥15 mL/min) newly initiated to apixaban or warfarin treatment between January 1, 2010, and December 31, 2017, at 315 general practitioner clinics and 87 hospitals across Japan. After applying propensity score matching, patient characteristics were well-balanced between the apixaban and warfarin groups (4,523 patients each). The incidence rate (per 100 person-years) of major bleeding was lower in the apixaban vs. warfarin group (1.17 vs. 1.64; hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.54-0.93; P=0.01), as was that of stroke/SE (1.14 vs. 1.73; HR, 0.65; 95% CI, 0.50-0.85; P<0.01). When patients were stratified by CrCl (≥50 mL/min and <50 mL/min), the P value for interaction was not statistically significant between subgroups (P=0.31 for major bleeding and P=0.32 for stroke/SE).

CONCLUSIONS

The benefit of apixaban over warfarin for the reduction in risk of major bleeding and stroke/SE could be generalizable to daily clinical practice and to patients with reduced renal function.

Real-world comparisons of reduced-dose non-vitamin K antagonist oral anticoagulants versus warfarin in atrial fibrillation: a systematic review and meta-analysis

We performed this meta-analysis to compare the efficacy and safety of reduced-dose non-vitamin K antagonist oral anticoagulants (NOACs) versus warfarin in patients with atrial fibrillation (AF). The PubMed and Embase databases were systematically searched until July 2019 for eligible studies that comparing the effect between any reduced-dose NOAC and warfarin in patients with AF. Risk ratios (RRs) and 95% confidence intervals (CIs) were pooled by using a random-effects model. A total of 14 observational cohorts were included. Compared with warfarin use, the use of reduced-dose NOACs was associated with decreased risks of stroke or systemic embolism (RR, 0.83; 95% CI 0.74-0.93), ischemic stroke (RR, 0.87; 95% CI 0.77-0.98), major bleeding (RR, 0.71; 95% CI 0.60-0.84), intracranial hemorrhage (RR, 0.51; 95% CI 0.44-0.60), and gastrointestinal bleeding (RR, 0.72; 95% CI 0.54-0.94), but not all cause death (RR, 0.84; 95% CI 0.67-1.06). In the subgroup analyses, all NOAC users had lower or similar rates of thromboembolic and bleeding events; and the reductions in stroke or systemic embolism, all-cause death, major bleeding, and gastrointestinal bleeding were more prominent in Asians than non-Asians. In conclusion, current published data suggest that the use of reduced-dose NOACs is non-inferior to warfarin in patients with AF (in particular Asians).

Non-vitamin K antagonist oral anticoagulants in Asian patients with atrial fibrillation: evidences from the real-world data

The role of non-vitamin K antagonist oral anticoagulants (NOACs) in stroke prevention remains unclear in Asian patients with atrial fibrillation (AF). Therefore, we performed a meta-analysis to compare the efficacy and safety outcomes of NOACs in Asian patients with AF from the real-world settings. The PubMed and Embase databases were systematically searched to identify eligible observational studies until June 2019. The odds ratios (OR) and 95% confidence intervals (CIs) were calculated and then pooled by a random-effects model. A total of 18 observational studies were included. Compared with warfarin, dabigatran (OR, 0.56, 95% CI 0.43-0.73), rivaroxaban (OR, 0.54, 95% CI 0.44-0.67), apixaban (OR, 0.41, 95% CI 0.35-0.48), and edoxaban (OR, 0.19, 95% CI 0.14- 0.25) reduced the risk of major bleeding, while dabigatran (OR, 0.78, 95% CI 0.71-0.85), rivaroxaban (OR, 0.74, 95% CI 0.68-0.82), and edoxaban (OR, 0.29, 95% CI 0.22-0.39) were associated with reduced risks of stroke or systemic embolism. In addition, dabigatran versus apixaban was associated with increased risks of ischemic stroke and gastrointestinal bleeding, while rivaroxaban versus apixaban was associated with elevated risks of stroke or systemic embolism, ischemic stroke, intracranial hemorrhage, and gastrointestinal bleeding. In Asian patients with AF, NOACs are non-inferior to warfarin for stroke prevention, and apixaban may be a better choice compared with dabigatran or rivaroxaban.

Phase I clinical trial of an antithrombotic drug protocol combining apixaban and clopidogrel in dogs

INTRODUCTION

Combining an antiplatelet drug, clopidogrel, with the direct oral Factor Xa inhibitor, apixaban, could provide an effective antithrombotic strategy in dogs. Thus, a limited 3 + 3 phase I dose-escalation clinical trial in healthy dogs was conducted to evaluate bleeding (primary end-point) and pharmacodynamic (PD)/pharmacokinetic (PK) parameters (secondary end-point).

ANIMALS

Eleven beagle dogs, median body weight 10.2 kg (9.7-10.9 kg), were enrolled.

METHODS

Four doses of apixaban (three dogs/dose) administered for eight days. Clopidogrel dose was fixed at 18.75 mg per os (PO) q 24 h with escalation of apixaban dose at 5 mg PO q 12 h, 5 mg PO q 8 h, 10 mg PO q 12 h, and 10 mg PO q 8 h. Laboratory testing included fecal occult blood, coagulation parameters, Factor X activity, apixaban concentration, platelet aggregometry, and thromboelastography on days 1, 3, and 8.

RESULTS

Evidence of bleeding was not observed at any dosage. Dose-dependent changes in PD/PK parameters between baseline and 3 h post-medication were observed including a prolongation of prothrombin time, a prolongation of activated partial thromboplastin time, a decrease of Factor X activity level, and increased apixaban concentration.

CONCLUSIONS

The combination of apixaban at a dosage range of approximately 0.5 mg/kg PO q 12 h to 1 mg/kg PO q 8 h and clopidogrel at approximately 1.8 mg/kg PO q 24 h did not cause bleeding over a one-week period in healthy dogs. Clinically relevant changes in PD/PK data occur at all dosage levels. This study provides a starting point for longer-term clinical trials to determine safety and efficacy.

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.

Dabigatran, rivaroxaban, and apixaban are superior to warfarin in Asian patients with non-valvular atrial fibrillation: An updated meta-analysis

BACKGROUND

Most of the randomized clinical trials that led to the wide use of non-vitamin K antagonist oral anticoagulants for stroke prevention in patients with atrial fibrillation (AF) originated from western countries.

AIM

To systematically review and quantitatively synthesize the real-world data regarding the efficacy and safety of dabigatran, rivaroxaban, and apixaban compared to warfarin for stroke prevention in Asian patients with non-valvular AF.

METHODS

Medline, Cochrane, and ClinicalTrial.gov databases were reviewed. A random-effect model meta-analysis was used and I-square was utilized to assess the heterogeneity. The primary outcome was ischemic stroke. The secondary outcomes were all-cause mortality, major bleeding, intracranial hemorrhage, and gastrointestinal bleeding.

RESULTS

Twelve studies from East Asia or Southeast Asia and 441450 patients were included. Dabigatran, rivaroxaban, and apixaban were associated with a significant reduction in the incidence of ischemic stroke [hazard ratio (HR) = 0.78, 95% confidence interval (CI): 0.65-0.94; HR = 0.79, 95%CI: 0.74-0.85, HR = 0.70, 95%CI: 0.62-0.78; respectively], all-cause mortality (HR = 0.68, 95%CI: 0.56-0.83; HR = 0.66, 95%CI: 0.52-0.84; HR = 0.66, 95%CI: 0.49-0.90; respectively), and major bleeding (HR = 0.61, 95%CI: 0.54-0.69; HR = 0.70, 95%CI: 0.54-0.90; HR = 0.58, 95%CI: 0.43-0.78; respectively) compared to warfarin.

CONCLUSION

Dabigatran, rivaroxaban, and apixaban appear to be superior to warfarin in both efficacy and safety in Asians with non-valvular AF.

Does Warfarin or Rivaroxaban at Low Anticoagulation Intensity Provide a Survival Benefit to Asian Patients With Atrial Fibrillation?

Background: Low-dose rivaroxaban and low-intensity warfarin are widely used in Asia for patients with atrial fibrillation (AF). However, in Asians, it is unclear whether low-dose rivaroxaban and low-intensity warfarin can improve the prognosis of AF. In this study, we investigate the survival benefits of low-dose rivaroxaban and low-intensity warfarin in Asian patients with AF in clinical practice. Methods: This cohort study used medical records in a single tertiary hospital in China, between 2019 and 2020, to identify patients with AF who used rivaroxaban or warfarin, or had no anticoagulant therapy. Follow-ups were performed through telephone contact or medical record review. Cox proportional hazards models were used to compare the risk of mortality of patients in the anticoagulant-untreated group vs. warfarin-treated groups and rivaroxaban-treated groups. Results: A total of 1727 AF patients, discharged between 2019 and 2020, were enrolled in this cohort, of which 873 patients did not use any anticoagulant, 457 patients received warfarin and 397 patients used rivaroxaban. Multivariable analysis showed that, of all the warfarin groups, patients with an international normalized ratio (INR) below 2, good INR control, or poor INR control had a significantly lower risk of mortality compared with that of patients without anticoagulants (HR 0.309, p = 0.0001; HR 0.387, p = 0.0238; HR 0.363, p < 0.0001). Multivariable Cox proportional hazard analyses also demonstrated that, compared with the no anticoagulant group, all rivaroxaban dosage groups (≤10 mg, HR 0.456, p = 0.0129; 15 mg, HR 0.246, p = 0.0003; 20 mg, HR 0.264, p = 0.0237) were significantly associated with a lower risk of mortality. Conclusion: Despite effects being smaller than observed with recommended optimal anticoagulation, the use of warfarin with an INR below 2, poor INR control and the use of low-dose rivaroxaban may still provide survival benefits, suggesting viable alternatives that enable physicians to better resolve decisional conflicts concerning the risks and benefits of anticoagulant therapies, as well as for patients in need of but unable to receive standard anticoagulant therapy due to bleeding risk or other factors, such as financial burden, concerns of adverse outcomes, as well as low treatment compliance and persistence.

Anticoagulant activity of apixaban can be estimated by multiple regression analysis

BACKGROUND

Information on apixaban anticoagulant activity is required to prevent major bleeding or thrombosis during its use.

METHODS

We enrolled 194 patients with nonvalvular atrial fibrillation (NVAF) in whom warfarin was replaced with apixaban: 105 (54.1%) received the standard dose of apixaban (5 mg twice daily [BID]; 5 mg group) and 89 (45.9%) received a reduced dose (2.5 mg BID; 2.5 mg group). Multiple regression analysis was performed to predict the prothrombin time of apixaban (PTa) based on factors including age, body weight (BW), serum creatinine, and CHA2DS2-VASc score.

RESULTS

PTa and PT of warfarin (PTw) were significantly correlated in both groups (correlation coefficient R = 0.239 [P = .014] in the 5 mg group; R = 0.248 [P = .019] in the 2.5 mg group). PTa in the 5 mg group was predicted as follows: 16.952-0.036 × BW +0.299 × CHA2DS2-VASc score (P < .0004; R = 0.378). However, in the 2.5 mg group, PTa could not be predicted. The mean of the predicted and measured PTa values in the 5 mg group was 15.6 s, which was similar to the mean measured PTa of 15.5 s in the 2.5 mg group.

CONCLUSIONS

PT can be predicted by a formula including simple clinical parameters in patients receiving the standard dose of apixaban. This simple predictive formula may help to stratify bleeding and thrombosis risks in patients treated with apixaban.

Real-World Comparative Effectiveness and Safety of Non-Vitamin K Antagonist Oral Anticoagulants vs. Warfarin in a Developing Country

We aimed to compare effectiveness and safety of the non-vitamin K antagonist oral anticoagulants (NOACs) vs. warfarin for stroke prevention in nonvalvular atrial fibrillation (NVAF) in a developing country where anticoagulation control with warfarin is suboptimal. A real-world study was conducted among patients with NVAF in Thailand receiving NOACs and warfarin from 9 hospitals during January 2012 to April 2018. Propensity-score weighting was used to balance covariates across study groups. Cox regression models were used to compare the risk of thromboembolism, major bleeding, and net adverse clinical events across matched cohorts. A total of 2,055 patients; 605, 604, 441, and 405 patients receiving warfarin, rivaroxaban, dabigatran, and apixaban, respectively, were included. Median (interquartile range) time in therapeutic range (TTR) for warfarin users was 49.5% (26.6%-70.3%). Compared with warfarin, NOACs were associated with a significant reduction in major bleeding either when analyzed as a group (adjusted hazard ratio (HR) (95% confidence interval (CI)) of 0.46 (0.34-0.62) or by each agent. Compared with warfarin users with poor TTR, apixaban (adjusted HR 0.48, 95% CI 0.26-0.86, P = 0.013) and dabigatran (adjusted HR 0.44, 95% CI 0.21-0.90, P = 0.025) were associated with a lower risk of thromboembolism, in addition to markedly lower risk of major bleeding. In a healthcare system where anticoagulation control with warfarin is suboptimal, use of NOACs was associated with a profound reduction in major bleeding. The effectiveness and safety advantages of NOACs were more pronounced compared with warfarin users with low TTR.

Anti-Factor Xa Activity of Standard and Japan-Specific Doses of Rivaroxaban in Thai Patients With Non-Valvular Atrial Fibrillation

BACKGROUND

Recommended rivaroxaban doses for stroke prevention in atrial fibrillation (SPAF) are 20 and 15 mg/day in patients with normal and reduced renal function, respectively, but lower doses (15 and 10 mg) have been tested and approved in Japan. It is not known whether 15 and 10 mg rivaroxaban are appropriate in other Asian populations. This study compared the anti-Factor Xa (FXa) activity of 20 and 15 mg rivaroxaban in Thai patients with normal renal function and 15 and 10 mg rivaroxaban in patients with reduced renal function.Methods and Results:Sixty non-valvular atrial fibrillation patients receiving rivaroxaban (mean [±SD] age 69.3±9.1 years, mean creatinine clearance 59.2±22.7 mL/min) were enrolled. The anti-FXa activity of standard rivaroxaban and Japan-specific doses was measured at peak and trough concentrations. Median anti-FXa activity at peak concentrations was significantly higher for the standard than Japan-specific dose. Median anti-FXa activity measured at the trough was significantly higher for the standard dose only in those with impaired renal function. A higher proportion of patients receiving the Japan-specific rather than standard dose had anti-FXa activity at peak concentrations within the expected range (87.7% vs. 64.4%; P=0.001). One-third of those receiving the standard dose had anti-FXa activity higher than the expected range.

CONCLUSIONS

A significantly higher proportion of Thai patients receiving the Japan-specific dose of rivaroxaban had anti-FXa activity at peak concentrations within the expected range.

Real-world Comparisons of Direct Oral Anticoagulants for Stroke Prevention in Asian Patients with Non-valvular Atrial Fibrillation: a Systematic Review and Meta-analysis

BACKGROUND

Whether four direct oral anticoagulants (DOACs) are superior to warfarin among Asians with non-valvular atrial fibrillation (NVAF) remains unclear in the real-world setting.

METHODS

We searched PubMed and Medline + Journals@Ovid + EMBASE from September 17, 2009 to May 4, 2019 to perform a systematic review and meta-analysis of all observational real-world studies comparing four DOACs with warfarin specifically focused on Asian patients with NVAF.

RESULTS

From the original 212 results retrieved, 18 studies were included in the meta-analysis. Overall, DOACs were associated with lower risks of thromboembolism (hazard ratio; [95% confidence interval], 0.70; [0.63-0.78]), acute myocardial infarction (0.67; [0.57-0.79]), all-cause mortality (0.62; [0.56-0.69]), major bleeding (0.59; [0.50-0.69]), intracranial hemorrhage (0.50; [0.40-0.62]), gastrointestinal bleeding (0.66; [0.46-0.95]), and any bleeding (0.82; [0.73-0.92]) than warfarin. There was statistic heterogeneity between DOACs for the risks of thromboembolism (P interaction = 0.03) and acute myocardial infarction (P interaction = 0.007) when compared to warfarin. However, all DOACs showed lower risks of thromboembolism and acute myocardial infarction than warfarin when pooling studies that compared individual DOAC with warfarin. With regard to the other outcomes when compared to warfarin, there was no statistical heterogeneity between DOACs. In addition, the effectiveness and safety of four DOACs versus warfarin persisted in the subgroups of either standard-dose or low-dose DOACs.

CONCLUSIONS

The meta-analysis shows that the DOACs had greater effectiveness and safety compared to warfarin in real-world practice for stroke prevention, among Asian patients with NVAF.

Safety and effectiveness of non-vitamin K oral anticoagulants versus warfarin in real-world patients with non-valvular atrial fibrillation: a retrospective analysis of contemporary Japanese administrative claims data

Objective

To assess the safety (ie, risk of bleeding) and effectiveness (ie, risk of stroke/systemic embolism (SE)) separately for four non-vitamin K oral anticoagulants (NOACs; apixaban, dabigatran, edoxaban and rivaroxaban) versus warfarin in Japanese patients with non-valvular atrial fibrillation (NVAF), including those at high risk of bleeding and treated with reduced doses of NOACs.

Methods

We conducted a retrospective analysis of electronic health records and claims data from 372 acute care hospitals in Japan for patients with NVAF newly initiated on NOACs or warfarin. Baseline characteristics were balanced using inverse probability of treatment weighting with stabilised weights (s-IPTW). Bleeding risk and stroke/SE risk were expressed as HRs with 95% CIs. Two sensitivity analyses were conducted.

Results

A total of 73 989 patients were eligible for analysis. Notably, 52.8%-81.9% of patients received reduced doses of NOACs. After applying s-IPTW, patient characteristics were well balanced across warfarin/NOAC cohorts. The mean within-cohort age, CHADS₂ score and CHA₂DS₂-VASc score were 76 years, 2.2-2.3 and 3.8, respectively. In all age categories, the majority of the HRs for major bleeding, any bleeding and stroke/SE were equal to or below 1 for all NOACs versus warfarin. Apixaban was the only NOAC associated with a significantly lower risk of any bleeding. There was a trend towards increased risk reduction with NOACs versus warfarin in patients with body weight ≥60 kg. In patients with renal disease, the HRs for apixaban versus warfarin were below 1 for major bleeding, any bleeding and stroke/SE, with statistical significance observed for the risk reduction in stroke/SE versus warfarin. In the sensitivity analysis, there were no large differences in HRs between the two observational periods.

Conclusions

In patients with NVAF primarily treated with reduced-dose NOACs, the risks of stroke/SE and major bleeding were significantly lower with NOACs versus warfarin.

Dabigatran for Japanese Patients with Atrial Fibrillation and Prior Stroke: A Subgroup Analysis of the J-Dabigatran Surveillance Program

BACKGROUND

The study objective was to evaluate long-term safety and effectiveness of dabigatran 110 mg and 150 mg twice daily (bid) in patients with nonvalvular atrial fibrillation (NVAF) with a focus on secondary stroke prevention.

METHODS

In J-Dabigatran Surveillance, 6772 patients newly initiated on dabigatran to prevent ischemic stroke and systemic embolism were enrolled in Japan (1042 sites, December 2011 to November 2013). This subgroup analysis included patients with (1302) and without (5071) previous stroke/transient ischemic attack (TIA). Case report forms were reviewed to determine incidence of outcome events.

RESULTS

In patients with previous stroke/TIA, the incidence rate for recurrent stroke/TIA was 2.48/100 patient-years (ischemic stroke 2.22, hemorrhagic stroke 0.18, TIA 0.12) and for major bleeding was 1.79/100 patient-years, including intracranial bleeding (0.55). Event rates for recurrent stroke/TIA or major bleeding were 1.2% (for both) for patients who started dabigatran less than 30 days after stroke onset and 0.3% (for both) for patients who started dabigatran more than or equal to 30 days after stroke onset, and were independent of dabigatran dose. For patients with previous stroke/TIA, 17% who received 110 mg bid did not meet dose reduction recommendations (DRRs) and 28% who received 150 mg bid met at least 1 DRR, but the dabigatran dose was not reduced. Use of DRRs did not have a major impact on the incidence rates of recurrent stroke/TIA and major bleeding.

CONCLUSION

Findings from this subgroup analysis support the real-world safety and effectiveness of long-term dabigatran in Japan, particularly for patients with NVAF in secondary prevention settings.

Elderly Bleeding Risk of Direct Oral Anticoagulants in Nonvalvular Atrial Fibrillation: A Systematic Review and Meta-Analysis of Cohort Studies

Introduction

The 2014 American Heart Association (AHA)/American College of Cardiology (ACC)/Heart Rhythm Society (HRS) guidelines recommend anticoagulation to reduce clot formation and the risk of thromboembolic events in patients with atrial fibrillation but does not specify guidelines for the elderly population. Direct oral anticoagulants (DOACs) are newer US FDA-approved alternatives to warfarin and include dabigatran, rivaroxaban, apixaban and edoxaban. The efficacy of DOACs is heavily researched, but few studies have evaluated their bleeding risk.

Objectives

This systematic review and meta-analysis investigates which DOAC has the lowest bleeding risk in elderly patients with nonvalvular atrial fibrillation (NVAF).

Methods

CINAHL and MEDLINE databases were searched using specific keywords, and 244 results were identified and screened. Inclusion criteria required a major bleeding event requiring hospitalization as an outcome and excluded patients with severe renal failure. Articles that met inclusion criteria were assessed for risk of bias using the Cochrane Tool to Assess Risk of Bias in Cohort Studies. Review Manager (version 5) was used to perform the random-effects model meta-analysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. P < 0.05 was considered statistically significant.

Results

Six articles met inclusion criteria and encompassed 446,042 patients in total. Apixaban and dabigatran had statistically significant risk reductions compared with warfarin, whereas rivaroxaban did not (HR 0.60 [95% CI 0.52–0.69], p < 0.00001; HR 0.79 [95% CI 0.70–0.90], p = 0.0005; HR 1.03 [95% CI 0.86–1.22], p = 0.77, respectively.) Data regarding edoxaban were limited and thus not included in the analysis.

Conclusion

Apixaban and dabigatran have a significantly decreased major bleeding risk (40 and 21%, respectively) compared with warfarin. There was no statistical difference in bleeding risk between rivaroxaban and warfarin. Head-to-head prospective randomized controlled trials are required to assess the true bleeding risk of each DOAC.

Potential of machine learning methods to identify patients with nonvalvular atrial fibrillation

Aim: Nonvalvular atrial fibrillation (NVAF) is associated with an increased risk of stroke however many patients are diagnosed after onset. This study assessed the potential of machine-learning algorithms to detect NVAF. Materials & methods: A retrospective database study using a Japanese claims database. Patients with and without NVAF were selected. 41 variables were included in different classification algorithms. Results: Machine learning algorithms identified NVAF with an area under the curve of >0.86; corresponding sensitivity/specificity was also high. The stacking model which combined multiple algorithms outperformed single-model approaches (area under the curve ≥0.90, sensitivity/specificity ≥0.80/0.82), although differences were small. Conclusion: Machine-learning based algorithms can detect atrial fibrillation with accuracy. Although additional validation is needed, this methodology could encourage a new approach to detect NVAF.

Effectiveness and Safety of Standard- and Low-Dose Rivaroxaban in Asians With Atrial Fibrillation

BACKGROUND

Low-dose rivaroxaban (10 mg/day) has been widely used in Asia for patients with atrial fibrillation (AF), although there is a lack of evidence regarding its effectiveness. In Asians, it is unclear whether low-dose rivaroxaban is equally effective as that of the standard dose or is associated with less bleeding risk.

OBJECTIVES

The aim of this study was to evaluate the effectiveness and safety of standard-dose (15 or 20 mg/day) and low-dose (10 mg/day) rivaroxaban in Asians with AF.

METHODS

Using data files from the National Health Insurance Research Database between May 1, 2014, and September 30, 2015, a retrospective population-based cohort study was conducted in patients diagnosed with AF or atrial flutter and treated with low- or standard-dose rivaroxaban. Patients were followed up until the first occurrence of the study outcome or the end of the observation period (December 31, 2015).

RESULTS

Among 6,558 eligible patients, a total of 2,373 and 4,185 patients took low- and standard-dose rivaroxaban, respectively. Compared to standard-dose rivaroxaban, low-dose rivaroxaban was associated with a significantly higher risk of myocardial infarction (subdistribution hazard ratio: 2.26; 95% confidence interval: 1.13 to 4.52), with similar risk of ischemic stroke, systemic embolism, major bleeding, and nonmajor clinically relevant bleeding.

CONCLUSIONS

Compared to standard-dose rivaroxaban, low-dose rivaroxaban in Asian patients with AF was associated with similar risks of thromboembolism and bleeding except myocardial infarction.

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

Indirect comparison of novel Oral anticoagulants among Asians with non-Valvular atrial fibrillation in the real world setting: a network meta-analysis

Background

The development of novel oral anticoagulants (NOACs) has changed the landscape of non-valvular atrial fibrillation (NVAF) management. In this study, the effectiveness and the safety of several NOACs were evaluated in a real-world setting among Asian patients with NVAF.

Methods

The literature search was conducted crossing different databases including Embase, MEDLINE, and the Cochrane Library from inception through March 1, 2019, for studies which included real-world perspectives comparing the individual NOACs with each other or with warfarin among Asians with NVAF. The primary outcomes were defined as stroke or systemic embolism (SSE) and major bleeding; ischemic stroke, all-cause death as well as intracranial bleeding were classified as the secondary outcomes.

Results

From sixteen real-world studies, a total of 312,827 Asian patients were included in this analysis. In comparison with warfarin, the utilization of apixaban, dabigatran, and rivaroxaban significantly lowered the risk of major bleeding (apixaban: HR 0.47, 95%CI 0.35–0.63; dabigatran: HR 0.59, 95%CI 0.47–0.73; rivaroxaban: HR 0.66, 95%CI 0.52–0.83) and lessened the all-cause death rate (apixaban: HR 0.29, 95%CI 0.16–0.52; dabigatran: HR 0.40, 95%CI 0.27–0.60; rivaroxaban: HR 0.42, 95%CI 0.28–0.65). Apixaban (HR 0.59; 95%CI 0.40–0.85) reduced the possibility of ischemic stroke when compared against dabigatran. Rivaroxaban showed a higher chance of causing an ischemic stroke (HR 1.61; 95%CI 1.08–2.41) and major bleeding (HR 1.39; 95%CI 1.02–1.90) than Apixaban.

Conclusions

Apixaban, dabigatran and rivaroxaban were more effective than warfarin on reducing the risks of stroke and haemorrhage; meanwhile, apixaban was likely to lower the risk of major bleeding comparing to rivaroxaban.

Trial registration

PROSPERO registry number: CRD42018086914.

Electronic supplementary material

The online version of this article (10.1186/s12872-019-1165-5) contains supplementary material, which is available to authorized users.

Safety and effectiveness of apixaban in Japanese patients with nonvalvular atrial fibrillation in clinical practice: A regulatory postmarketing surveillance, the STANDARD study

BACKGROUND

Apixaban, a non-vitamin K oral anticoagulant (NOAC), was approved in Japan in 2012 for the prevention of thromboembolic events in patients with nonvalvular atrial fibrillation (NVAF). However, the safety and effectiveness of apixaban in clinical practice have not yet been elucidated thoroughly among Japanese NVAF patients.

METHODS

A postmarketing surveillance study was conducted to determine the safety and effectiveness of apixaban. Patients were followed-up for 104 weeks. Outcome events included adverse drug reactions (ADRs), hemorrhages, and thromboembolic events (ischemic stroke, systemic embolism [SE], and transient ischemic attack [TIA]).

RESULTS

Among 6306 NVAF patients in the safety analysis set (age, 74.5 ± 10.1 years; women, 41.1%; and CHADS 2 score, 2.0 ± 1.4), 3600 patients (57.1%) received the standard dose (5 mg twice daily) and 2694 (42.7%) received a reduced dose (2.5 mg twice daily) of apixaban. ADRs occurred in 604 patients (9.58%), with the most common being epistaxis (0.86%), subcutaneous hemorrhage (0.67%), and hematuria (0.57%). Incidence rate of any hemorrhages and major hemorrhage was 5.52% per year and 2.36% per year, respectively. Incidence rate of ischemic stroke/SE/TIA was 1.00% per year among 6286 patients in the effectiveness analysis set. Among three subgroups (3106 apixaban initiators, 2038 patients switched from warfarin, and 1118 patients switched from other NOACs), incidence rates of major hemorrhage (P = 0.221 for trend) and ischemic stroke/SE/TIA (P = 0.686 for trend) were comparable.

CONCLUSIONS

No new safety signals of apixaban were identified in Japanese NVAF patients. Safety and effectiveness of apixaban were consistent with those in the ARISTOTLE study.

Differences in safety and efficacy of oral anticoagulants in patients with non-valvular atrial fibrillation: A Bayesian analysis

BACKGROUND

Novel oral anticoagulants are the cornerstone of therapy for non-valvular atrial fibrillation patients to lower the risk of ischaemic stroke. Given the lack of head-to-head comparisons among oral anticoagulants, a Bayesian analysis was used to evaluate their safety and efficacy based on studies from real-world practice.

METHODS

The PubMed, Embase, Cochrane and Web of Science databases were searched for relevant studies. Bayesian analyses were conducted to estimate hazard ratios (HR) and 95% credible intervals (CrI) for the safety and efficacy of oral anticoagulants.

RESULTS

In the 22 studies included in our analysis, novel oral anticoagulants exhibited a clear advantage over warfarin in preventing ischaemic stroke, haemorrhagic stroke and, especially, intracranial haemorrhage. Incidence of major bleeding was lowest for apixaban, followed by dabigatran, warfarin and rivaroxaban. Gastrointestinal bleeding risk was lowest for apixaban, followed by warfarin, and was slightly lower for dabigatran than for rivaroxaban with no statistical difference (HR 1.05, 95% CrI 0.99-1.11). Ischaemic stroke risk was lowest for rivaroxaban, followed by apixaban, dabigatran and warfarin (HR 1.13, 95% CrI 1.07-1.20).

CONCLUSION

In real-world practice, apixaban may represent the optimal treatment in terms of safety and efficacy for patients with non-valvular atrial fibrillation. For patients with high risk of ischaemic events but low bleeding risk, rivaroxaban may be preferable.

Safety of direct oral anticoagulants in real-world clinical practice: translating the trials to everyday clinical management

INTRODUCTION

Direct oral anticoagulants (DOACs) may be regarded as some of the most successful innovations in recent times. These drugs which were specifically developed to overcome the challenges posed by warfarin did just that and in the process, have changed the outlook towards stroke prevention with anticoagulation. The decade of experience with these drugs that has resulted in the availability of large scale data on their safety profile has aided this. Areas covered: This review examines existing real-world studies (RWS) and their interpretation to better appreciate how they either complement or contradict findings from the hallmark trials. Specific focus has been made on the safety of DOACs, on their risks of major bleeding, intra-cranial haemorrhage (ICH), gastro-intestinal (GI) bleeding and all-cause mortality compared to warfarin and each other. DOAC use in the elderly and other sub-groups are briefly discussed. Expert opinion: Results for safety outcomes according to 'real world evidence' (RWE) are in-keeping with randomised controlled trials (RCTs) and currently, all 4 DOACs have been deemed at least as effective as warfarin, while demonstrating superiority in some aspects. While real world studies act as a complementary source of knowledge, traditional RCTs remain the gold standard for determining cause-effect relationships.

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.

Major bleeding with antithrombotic agents: a 2012-2015 study using the French nationwide Health Insurance database linked to emergency department records within five areas - rationale and design of SACHA study

Bleeding represents the most recognized and feared complications of antithrombotic drugs including oral anticoagulants. Previous studies showed inconsistent results on the safety profile. Among explanations, bleeding definition could vary and classification bias exists related to the lack of medical evaluation. To quantify the risk of major haemorrhagic event and event-free survival associated with antithrombotic drugs (vitamin K antagonist [VKA], non-VKA anticoagulant [NOAC], antiplatelet agent, parenteral anticoagulant) in 2012-2015, we linked the French nationwide Health Insurance database (SNIIRAM) with a local 'emergency database' (clinical and biological data collected in clinical records). In the VKA-NOAC comparison, a Cox regression analysis will be used to estimate the hazard ratio of major haemorrhagic event adjusted on gender, modified HAS-BLED score and comorbidities. A distinction on the type of major haemorrhagic event (intracranial, gastrointestinal and other haemorrhagic events) was made. We present here the study protocol and the database linkage results. Using six linkage keys, among 3 837 557 hospital visits identified in SNIIRAM, 5264 have been matched with a major haemorrhagic event identified in the 'emergency database', thus clinically confirmed. The 1090 unmatched haemorrhagic events could be explained by the fact that patients were not extracted in the SNIIRAM database (patients living in accommodation establishment with internal use of pharmacy, military people with specific insurance…). We showed the value of SNIIRAM enrichment with a clinical database, a necessary step to categorize haemorrhagic events by a clinically relevant definition and medical validation; it will allow to estimate more accuracy each type of haemorrhagic event.

Medication use in older patients and age-blind approach: narrative literature review (insufficient evidence on the efficacy and safety of drugs in older age, frequent use of PIMs and polypharmacy, and underuse of highly beneficial nonpharmacological strategies)

INTRODUCTION

The importance of rational drug therapy is increasing with the aging of the population. Since one of the main reasons for inappropriate drug prescribing is also the "age-blind" approach, which results in ageist practices, this narrative literature review focuses on the description of the main barriers related to insufficient individualization of drug regimens associated with such age-blind approaches.

METHODOLOGY

A narrative literature review using the PubMed, WoS, Embase, and Scopus databases was conducted by the EU COST Action IS1402. Experts in different scientific fields from six countries (the Czech Republic, Spain, Portugal, Hungary, Serbia, and Turkey) worked in four specific areas: (1) underrepresentation of older adults in clinical trials and clinical and ethical consequences; (2) insufficient consideration of age-related changes and geriatric frailty in the evaluation of the therapeutic value of drugs; (3) frequent prescribing of potentially inappropriate medications (PIMs); and (4) frequent underuse of highly beneficial nonpharmacological strategies (e.g., exercise).

RESULTS

Older patients are underrepresented in clinical trials. Therefore, rigorous observational geriatric research is needed in order to obtain evidence on the real efficacy and safety of frequently used drugs, and e.g. developed geriatric scales and frailty indexes for claims databases should help to stimulate such research. The use of PIMs, unfortunately, is still highly prevalent in Europe: 22.6% in community-dwelling older patients and 49.0% in institutionalized older adults. Specific tests to detect the majority of age-related pharmacological changes are usually not available in everyday clinical practice, which limits the estimation of drug risks and possibilities to individualize drug therapy in geriatric patients before drug prescription. Moreover, the role of some nonpharmacological  strategies is highly underestimated in older adults in contrast to frequent use of polypharmacy. Among nonpharmacological strategies, particularly physical exercise was highly effective in reducing functional decline, frailty, and the risk of falls in the majority of clinical studies.

CONCLUSION

Several regulatory and clinical barriers contribute to insufficient knowledge on the therapeutic value of drugs in older patients, age-blind approach, and inappropriate prescribing. New clinical and observational research is needed, including data on comprehensive geriatric assessment and frailty, to document the real efficacy and safety of frequently used medications.

Comparative effectiveness and safety of warfarin and dabigatran in patients with non-valvular atrial fibrillation in Japan: A claims database analysis

BACKGROUND

Antithrombotic therapy, including direct oral anticoagulants, is recommended in patients with non-valvular atrial fibrillation (NVAF) who are at intermediate-to-high risk of stroke. The aims of this study were to assess the patterns of oral anticoagulant (OAC) prescription in Japanese patients with NVAF and compare the effectiveness and safety of dabigatran and warfarin.

METHODS

This was a retrospective observational study of adults with NVAF who initiated dabigatran or warfarin between March 14, 2011 and June 30, 2016, using electronic claims data of approximately 12.94 million patients from 230 hospitals. Propensity score matching was used to derive equal patient cohorts. Outcomes included the combined incidence of stroke, systemic embolism, and intracranial bleeding (primary endpoint) and the incidence of major bleeding (secondary endpoint).

RESULTS

Overall, 400,884 patients were included. Among those prescribed an OAC, warfarin was the most common (34.3%). For the comparison of dabigatran and warfarin, 4606 patients were propensity-score matched in each cohort. Dabigatran recipients had lower incidences of stroke, systemic embolism, and intracranial bleeding [29.0 vs. 35.6 per 1000 patient-years; hazard ratio (HR), 0.72; 95% confidence interval (CI): 0.53-0.97; p=0.031] and major bleeding (6.4 vs. 11.3 per 1000 patient-years; HR, 0.55; 95% CI: 0.30-0.99; p=0.048). The most common type of bleeding in both groups was gastrointestinal and the incidence was lower in dabigatran recipients (1.6 vs. 6.4 per 1000 patient-years; HR, 0.24; 95% CI: 0.08-0.69; p=0.009).

CONCLUSIONS

In Japan, dabigatran was associated with a lower risk of stroke, systemic embolism, and intracranial bleeding and major bleeding compared with warfarin in patients with NVAF.

Safety and effectiveness of apixaban in comparison to warfarin in patients with nonvalvular atrial fibrillation: a propensity-matched analysis from Japanese administrative claims data

OBJECTIVE

To investigate the risk of bleeding events and stroke/systemic embolism (SE) among Japanese patients with nonvalvular atrial fibrillation (NVAF), focusing on the initial dosage of apixaban and patient age.

METHODS

This retrospective cohort study used de-identified electronic health records based claims data from 314 acute-care hospitals in Japan. NVAF patients newly initiated on warfarin or apixaban, with no prescription during the 180-day blanking period, were eligible. Patients were allocated to receive warfarin or 5 or 2.5 mg twice daily (BID) apixaban. One-to-one propensity-score matching was used to balance patient characteristics between apixaban and warfarin.

RESULTS

Among 31,006 eligible patients, 11,972 matched pairs were identified for apixaban versus warfarin. Mean age ± standard deviation was 77.7 ± 10.0 and 77.6 ± 10.0 years and CHADS₂ score was 2.2 ± 1.4 and 2.2 ± 1.4 for warfarin and apixaban, respectively. In the apixaban cohort, 39.4% of patients received the standard dose (5 mg BID) and 60.6% received the reduced dose (2.5 mg BID). Incidence rates (events per 100 person-years) of major bleeding, any bleeding and stroke/SE were 3.7, 23.1 and 3.1, and 2.5, 18.6 and 2.0 for warfarin and apixaban cohorts, respectively. Apixaban was associated with a significantly lower risk of any bleeding (hazard ratio [HR] 0.809, 95% confidence interval [CI] 0.731-0.895; p < .001), major bleeding (HR 0.655, 95% CI 0.505-0.849; p = .001) and stroke/SE (HR 0.637, 95% CI 0.478-0.850; p = .002).

CONCLUSIONS

Our observational data from clinical practice broadly confirms the safety and efficacy results of pivotal randomized controlled trials of apixaban for stroke prevention among NVAF patients.

Risks and benefits of direct oral anticoagulants versus warfarin in a real world setting: cohort study in primary care

OBJECTIVE

To investigate the associations between direct oral anticoagulants (DOACs) and risks of bleeding, ischaemic stroke, venous thromboembolism, and all cause mortality compared with warfarin.

DESIGN

Prospective open cohort study.

SETTING

UK general practices contributing to QResearch or Clinical Practice Research Datalink.

PARTICIPANTS

132 231 warfarin, 7744 dabigatran, 37 863 rivaroxaban, and 18 223 apixaban users without anticoagulant prescriptions for 12 months before study entry, subgrouped into 103 270 patients with atrial fibrillation and 92 791 without atrial fibrillation between 2011 and 2016.

MAIN OUTCOME MEASURES

Major bleeding leading to hospital admission or death. Specific sites of bleeding and all cause mortality were also studied.

RESULTS

In patients with atrial fibrillation, compared with warfarin, apixaban was associated with a decreased risk of major bleeding (adjusted hazard ratio 0.66, 95% confidence interval 0.54 to 0.79) and intracranial bleeding (0.40, 0.25 to 0.64); dabigatran was associated with a decreased risk of intracranial bleeding (0.45, 0.26 to 0.77). An increased risk of all cause mortality was observed in patients taking rivaroxaban (1.19, 1.09 to 1.29) or on lower doses of apixaban (1.27, 1.12 to 1.45). In patients without atrial fibrillation, compared with warfarin, apixaban was associated with a decreased risk of major bleeding (0.60, 0.46 to 0.79), any gastrointestinal bleeding (0.55, 0.37 to 0.83), and upper gastrointestinal bleeding (0.55, 0.36 to 0.83); rivaroxaban was associated with a decreased risk of intracranial bleeding (0.54, 0.35 to 0.82). Increased risk of all cause mortality was observed in patients taking rivaroxaban (1.51, 1.38 to 1.66) and those on lower doses of apixaban (1.34, 1.13 to 1.58).

CONCLUSIONS

Overall, apixaban was found to be the safest drug, with reduced risks of major, intracranial, and gastrointestinal bleeding compared with warfarin. Rivaroxaban and low dose apixaban were, however, associated with increased risks of all cause mortality compared with warfarin.