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.

Safety and efficacy of non-vitamin K antagonist oral anticoagulants compared with well-controlled warfarin in Thai patients with atrial fibrillation

Background

In trials of patients with atrial fibrillation (AF), non-vitamin K antagonist oral anticoagulants (NOACs) were not inferior to warfarin for thromboembolic and bleeding events. However, there are scant data comparing the efficacy and safety of NOACs in patients with AF with that of well-controlled warfarin treatment in such patients.

Objectives

To compare total bleeding and thromboembolic events in patients with AF who received NOACs, with the same events in those who received well-controlled warfarin treatment.

Methods

We used retrospective data from patients with AF who received NOACs or well-controlled warfarin at the Central Chest Institute of Thailand from January 2017 to December 2019. The primary outcome was total bleeding or thromboembolic events or both. The secondary outcome was all-cause mortality, total bleeding events including major or minor bleeding, and thromboembolic events including ischemic stroke or systemic embolization.

Results

We included data from 180 patients with AF, 90 who received NOACs and 90 who received well-controlled warfarin. The average time in the therapeutic range for those who received warfarin was 84.9% ± 9.8%. The patients who received well-controlled warfarin had more frequent thromboembolic or total bleeding events or both than those who received NOACs (odds ratio [OR] 3.17; 95% confidence interval [CI] 2.27-4.07; P = 0.01). There were more minor bleeding events in those who received well-controlled warfarin (OR 3.75; 95% CI 2.79-4.71; P = 0.01). However, there was no significant difference in thromboembolic events, major bleeding, or all-cause mortality between the 2 groups.

Conclusions

Thai patients with AF who received NOACs had less thromboembolic or total bleeding events than those who received well-controlled warfarin treatment.

Non-Vitamin K Antagonist Oral Anticoagulants Versus Warfarin in Patients With Cancer and Atrial Fibrillation: A Systematic Review and Meta-Analysis

Background

Several studies have investigated the effect of non–vitamin K antagonist oral anticoagulants (NOACs) in atrial fibrillation (AF) patients with cancer, but the results remain controversial. Therefore, we conducted a meta‐analysis to compare the efficacy and safety of NOACs versus warfarin in this population.

Methods and Results

We systematically searched the PubMed and Embase databases until February 16, 2019 for studies comparing the effect of NOACs with warfarin in AF patients with cancer. Risk ratios (RRs) with 95% CIs were extracted and pooled by a random‐effects model. Five studies involving 8908 NOACs and 12 440 warfarin users were included. There were no significant associations between cancer status and risks of stroke or systemic embolism, major bleeding, or death in AF patients. Compared with warfarin, NOACs were associated with decreased risks of stroke or systemic embolism (RR, 0.52; 95% CI, 0.28–0.99), venous thromboembolism (RR, 0.37, 95% CI, 0.22–0.63), and intracranial or gastrointestinal bleeding (RR, 0.65; 95% CI, 0.42–0.98) and with borderline significant reductions in ischemic stroke (RR, 0.63; 95% CI, 0.40–1.00) and major bleeding (RR, 0.73; 95% CI, 0.53–1.00). In addition, risks of efficacy and safety outcomes of NOACs versus warfarin were similar between AF patients with and without cancer.

Conclusions

In patients with AF and cancer, compared with warfarin, NOACs had lower or similar rates of thromboembolic and bleeding events and posed a reduced risk of venous thromboembolism.

Hospital admissions for bleeding events associated with treatment with apixaban, dabigatran and rivaroxaban

Objectives

To analyse the hospital admissions for bleeding events associated with treatment with direct oral anticoagulants (DOACs). To describe the characteristics and outcomes of those patients.

Methods

A retrospective observational study was carried out in the framework of an integral risk management plan of drugs and proactive pharmacovigilance of hospital admissions for bleeding associated with apixaban, dabigatran and rivaroxaban from April 2015 through December 2016. Cases were identified using the information management tool of Orion Clinic (hospital electronic medical history) and by reviewing the hospital discharge reports. Various biometric, clinical and pharmacotherapeutic variables of each patient were registered.

Results

37 hospitalisation episodes for DOAC-induced bleeding in 32 patients (15 received rivaroxaban, 9 apixaban and 8 dabigatran) were detected, representing an incidence rate of 3.44 per 100 person-years (95% CI 2.35 to 4.86). The most common bleeding site was gastrointestinal (27 cases, 73.0%). Intracranial bleeding was rare (three cases, 8.1%). Four patients (12.5%) were receiving DOACs at full doses and had a 'dose reduction indication'. The mean (SD) length of stay was 8.4 (5.2) days. Three patients (8.1%) died during the hospitalisation. Among bleeding episodes without fatal outcome, DOACs were stopped in 14 cases, continued in 14 cases, switched for another DOAC in two cases and the dose was reduced in four cases.

Conclusions

DOACs are associated with serious bleeding events that require hospitalisation. The risk/benefit ratio assessment considering patient preferences and an individualised follow-up, especially in patients who are elderly, polymedicated or have impaired renal function, can help to reinforce the safe use of DOACs.

Effectiveness and Safety of Non-vitamin K Antagonist Oral Anticoagulants for Atrial Fibrillation and Venous Thromboembolism: A Systematic Review and Meta-analyses

PURPOSE

The findings from the observational studies comparing the effectiveness and safety of non-vitamin K antagonist oral anticoagulants (NOACs) versus vitamin K antagonists (VKAs) for atrial fibrillation (AF) and venous thromboembolism (VTE) are inconsistent. We conducted separate meta-analyses examining the efficacy/effectiveness and safety of NOACs versus VKAs by disease (AF vs VTE), study design (randomized controlled trials [RCTs] vs observational studies), and NOAC (dabigatran, rivaroxaban, apixaban, and edoxaban).

METHODS

The main data sources included PubMed/MEDLINE, EMBASE, Web of Science, CINAHL, and Scopus from January 1, 2005, to February 15, 2016. We searched for Phase III RCTs and observational studies comparing NOACs versus VKAs. The primary outcomes were stroke/systemic embolism (SE) for AF; recurrent VTE/fatal pulmonary embolism (PE) for VTE; and major bleeding for both conditions. Secondary outcomes included stroke and myocardial infarction (MI) for AF, recurrent deep vein thrombosis (DVT)/PE for VTE, and mortality, intracranial hemorrhage (ICH), and gastrointestinal bleeding for both conditions. Pooled hazard ratios (HRs) were reported by using inverse variance-weighted random effects models.

FINDINGS

A total of 13 RCTs and 27 observational studies (AF, n = 32; VTE, n = 8) were included. For AF, dabigatran and VKAs were comparable for stroke/SE risk in 1 RCT (HR, 0.77 [95% CI, 0.57-1.03]) and 6 observational studies (HR, 1.03 [95% CI, 0.83-1.27]). Rivaroxaban had a 20% decreased risk of stroke/SE in 3 RCTs (HR, 0.80 [95% CI, 0.67-0.95]) compared with VKA, but the effect was nonsignificant in 3 observational studies (HR, 0.78 [95% CI, 0.59-1.04]). Apixaban decreased stroke/systemic embolism risk (HR, 0.79 [95% CI, 0.66-0.95]) compared with VKA in 1 RCT, but edoxaban was comparable to VKA (HR, 0.99 [95% CI, 0.77-1.28]) in 1 RCT (no observational studies available for apixaban/edoxaban). Dabigatran, apixaban, and edoxaban decreased the risk of hemorrhagic stroke, mortality, major bleeding, and ICH by 10% to 71% compared with VKAs but not rivaroxaban. For VTE, NOACs and VKAs were comparable for recurrent VTE/fatal PE/DVT/PE risk in 7 RCTs and 1 observational study. The 7 RCTs demonstrated a 32% to 69% decreased risk of major bleeding for dabigatran, rivaroxaban, and apixaban compared with VKAs. No difference was shown in 1 rivaroxaban observational study (HR, 0.77 [95% CI, 0.40-1.49]) and 1 edoxaban RCT (HR, 0.84 [95% CI, 0.59-1.20]). Except for dabigatran, the NOACs had a 61% to 86% decreased risk of ICH and gastrointestinal bleeding.

IMPLICATIONS

Overall, NOACs were comparable or superior to VKAs. Although no observational studies are currently available for apixaban/edoxaban, a few notable inconsistencies exist for dabigatran (ischemic stroke, MI) and rivaroxaban (stroke/SE, major bleeding in VTE) between RCTs and observational studies. Individualizing NOAC/VKA therapy based on benefit/safety profiles and patient characteristics is suggested.

Is an Oral Anticoagulant Necessary for Young Atrial Fibrillation Patients With a CHA2DS2-VASc Score of 1 (Men) or 2 (Women)?

Background

Recent studies demonstrated that oral anticoagulants (OACs) should be considered for patients with atrial fibrillation and 1 risk factor in addition to sex. Because age is an important determinant of ischemic stroke, the strategy for stroke prevention may be different for these patients in different age strata. The aim of this study was to investigate whether OACs should be considered for patients aged 20 to 49 years with atrial fibrillation and a CHA₂DS₂‐VASc score of 1 (men) or 2 (women).

Methods and Results

Using the Taiwan National Health Insurance Research Database, 7374 male patients with atrial fibrillation and a CHA₂DS₂‐VASc score of 1 and 4461 female patients with atrial fibrillation and a CHA₂DS₂‐VASc score of 2 and all without antithrombotic therapies were identified and stratified into 3 groups by age. The threshold for the initiation of OACs for stroke prevention was set at a stroke rate of 1.7% per year for warfarin and 0.9% per year for non–vitamin K antagonist OACs. Among male patients aged 20 to 49 years with a CHA₂DS₂‐VASc score of 1, the risk of ischemic stroke was 1.30% per year and ranged from 0.94% per year for those with hypertension to 1.71% for those with congestive heart failure. Among female patients aged 20 to 49 years with a CHA₂DS₂‐VASc score of 2, the risk of ischemic stroke was 1.40% per year and ranged from 1.11% per year for those with hypertension to 1.67% for those with congestive heart failure.

Conclusions

For atrial fibrillation patients aged 20 to 49 years with 1 risk factor in addition to sex, non–vitamin K antagonist OACs should be considered for stroke prevention to minimize the risk of a potentially fatal or disabling event.

Effectiveness and Safety of Dabigatran, Rivaroxaban, and Apixaban Versus Warfarin in Nonvalvular Atrial Fibrillation

BACKGROUND

The introduction of non-vitamin K antagonist oral anticoagulants has been a major advance for stroke prevention in atrial fibrillation; however, outcomes achieved in clinical trials may not translate to routine practice. We aimed to evaluate the effectiveness and safety of dabigatran, rivaroxaban, and apixaban by comparing each agent with warfarin.

METHODS AND RESULTS

Using a large US insurance database, we identified privately insured and Medicare Advantage patients with nonvalvular atrial fibrillation who were users of apixaban, dabigatran, rivaroxaban, or warfarin between October 1, 2010, and June 30, 2015. We created 3 matched cohorts using 1:1 propensity score matching: apixaban versus warfarin (n=15 390), dabigatran versus warfarin (n=28 614), and rivaroxaban versus warfarin (n=32 350). Using Cox proportional hazards regression, we found that for stroke or systemic embolism, apixaban was associated with lower risk (hazard ratio [HR] 0.67, 95% CI 0.46-0.98, P=0.04), but dabigatran and rivaroxaban were associated with a similar risk (dabigatran: HR 0.98, 95% CI 0.76-1.26, P=0.98; rivaroxaban: HR 0.93, 95% CI 0.72-1.19, P=0.56). For major bleeding, apixaban and dabigatran were associated with lower risk (apixaban: HR 0.45, 95% CI 0.34-0.59, P<0.001; dabigatran: HR 0.79, 95% CI 0.67-0.94, P<0.01), and rivaroxaban was associated with a similar risk (HR 1.04, 95% CI 0.90-1.20], P=0.60). All non-vitamin K antagonist oral anticoagulants were associated with a lower risk of intracranial bleeding.

CONCLUSIONS

In patients with nonvalvular atrial fibrillation, apixaban was associated with lower risks of both stroke and major bleeding, dabigatran was associated with similar risk of stroke but lower risk of major bleeding, and rivaroxaban was associated with similar risks of both stroke and major bleeding in comparison to warfarin.

Effect of Adherence to Oral Anticoagulants on Risk of Stroke and Major Bleeding Among Patients With Atrial Fibrillation

BACKGROUND

In comparison to warfarin, non-vitamin K antagonist oral anticoagulants (NOACs) have the advantages of ease of dosing, fewer drug interactions, and lack of need for ongoing monitoring. We sought to evaluate whether these advantages translate to improved adherence and whether adherence is associated with improved outcomes in patients with atrial fibrillation.

METHODS AND RESULTS

We performed a retrospective cohort analysis by using a large US commercial insurance database to identify 64 661 patients with atrial fibrillation who initiated warfarin, dabigatran, rivaroxaban, or apixaban treatment between November 1, 2010, and December 31, 2014. During a median of 1.1 y of follow-up, 47.5% of NOAC patients had a proportion of days covered of ≥80%, compared with 40.2% in warfarin patients (P<0.001). Patients with CHA2DS2-VASc (risk based on the presence of congestive heart failure, hypertension age 65-74 y, age ≥75 y, diabetes mellitus, prior stroke or transient ischemic attack, vascular disease, sex category) score ≥4 were at increased risk of stroke when they were not taking anticoagulation ≥1 month versus <1 week (1-3 months: hazard ratio [HR] 1.96, 3-6 months: HR 2.64, ≥6 months: HR 3.66; all P<0.001). Patients with CHA2DS2-VASc score 2 or 3 were at increased risk of stroke when they were not taking anticoagulation ≥6 months (HR 2.73, P<0.001). In these patients with CHA2DS2-VASc score ≥2, nonadherence was not associated with intracranial hemorrhage. Among patients with CHA2DS2-VASc score 0 or 1, time not taking anticoagulation was not associated with stroke, but not taking anticoagulation ≥3 months was associated with a significant reduction of bleeding.

CONCLUSIONS

Adherence to anticoagulation is poor in practice and may be modestly improved with NOACs. Adherence to therapy appears to be most important in patients with CHA2DS2-VASc score ≥2, whereas the benefits of anticoagulation may not outweigh the harms in patients with CHA2DS2-VASc score 0 or 1.