Cardiovascular, Bleeding, and Mortality Risks of Dabigatran in Asians With Nonvalvular Atrial Fibrillation

Low-dose non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation

In the last decade, non-vitamin K antagonist oral anticoagulants (NOACs), a new generation of OACs, were introduced to prevent thromboembolism in patients with atrial fibrillation. Although vitamin K-dependent anticoagulants have long been used as OACs, their inherent disadvantage of considerable bleeding complications has limited their use. NOACs demonstrate similar or superior clinical outcomes to those of warfarin. Although strict dose reduction criteria are recommended for NOACs, low-dose NOACs are frequently utilized, especially in Asian patients. Low-dose NOACs have shown clinical outcomes similar to those of warfarin in randomized controlled trials (RCTs) and real-world studies. However, off-label low-dose NOACs have shown inconsistent results compared with standard-dose NOACs and warfarin. Therefore, strict dose reduction criteria for NOACs should be followed until RCTs confirm the issues associated with NOAC underdosing.

Real world time trends in antithrombotic treatment for newly diagnosed atrial fibrillation in China: reports from the GLORIA-AF Phase III registry : Trends in antithrombotic therapy use in China

BACKGROUND

Stroke prevention with oral anticoagulant (OAC) therapy, including non-vitamin K antagonist oral anticoagulants (NOACs), is recommended in patients with atrial fibrillation (AF). This analysis describes the antithrombotic prescription patterns for Chinese patients enrolled post-dabigatran approval during Phase II and III of the Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF) program in China.

METHODS

Patients aged ≥ 18 years with newly diagnosed (< 3 months before baseline visit) nonvalvular AF at risk of stroke (CHA₂DS₂-VASc score ≥ 1) were consecutively enrolled in the GLORIA-AF registry. This cross-sectional analysis provides descriptive comparison of Chinese patients in Phase III (2015-2016) with those enrolled in Phase II (2013-2014).

RESULTS

Overall, 1,018 and 1,911 Chinese patients were eligible for analysis in Phase II and III, respectively. Most patients (69.6% and 69.1%, respectively) had high stroke risk (CHA₂DS₂-VASc score ≥ 2 for males and ≥ 3 for females). High bleeding risk (HAS-BLED score ≥ 3) rates were similar (17.3% for Phase II, 17.6% for Phase III). In Phase II, 5.8%, 15.2%, 36.7% and 42.2% of patients were prescribed NOACs, vitamin K antagonists (VKAs), antiplatelet therapies or no antithrombotic treatment, respectively. The corresponding figures were 17.2%, 23.5%, 37.4% and 21.8% for patients in Phase III, with an overall increase in OAC prescriptions (NOACs or VKAs). In patients with high stroke risk, the prescription patterns in Phase II were 5.6%, 14.4%, 41.0% and 38.9% for NOACs, VKAs, antiplatelets or no antithrombotic treatment, respectively. The respective proportions in Phase III were 15.1%, 23.5%, 40.9% and 20.5%.

CONCLUSIONS

Since the availability of dabigatran in China, the overall trend of OAC, including NOAC, prescriptions in Chinese patients with nonvalvular AF has increased over time, albeit with VKAs as the most common antithrombotic treatment. Most patients, including those at high stroke risk, remain undertreated according to best practice guidelines.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01468701.

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.

Prescribing Trends of Oral Anticoagulants in US Patients With Cirrhosis and Nonvalvular Atrial Fibrillation

Background Many patients with cirrhosis have concurrent nonvalvular atrial fibrillation (NVAF). Data are lacking regarding recent oral anticoagulant (OAC) usage trends among US patients with cirrhosis and NVAF. Methods and Results Using MarketScan claims data (2012-2019), we identified patients with cirrhosis and NVAF eligible for OACs (CHA2DS2-VASc score ≥2 [men] or ≥3 [women]). We calculated the yearly proportion of patients prescribed a direct OAC (DOAC), warfarin, or no OAC. We stratified by high-risk features (decompensated cirrhosis, thrombocytopenia, coagulopathy, chronic kidney disease, or end-stage renal disease). Among 32 487 patients (mean age=71.6 years, 38.5% women, 15.1% with decompensated cirrhosis, mean CHA2DS2-VASc=4.2), 44.6% used OACs within 180 days of NVAF diagnosis, including DOACs (20.2%) or warfarin (24.4%). Compared with OAC nonusers, OAC users were less likely to have decompensated cirrhosis (18.6% versus 10.7%), thrombocytopenia (19.5% versus 12.5%), or chronic kidney disease/end-stage renal disease (15.5% versus 14.0%). Between 2012 and 2019, warfarin use decreased by 21.0% (32.0% to 11.0%), whereas DOAC use increased by 30.6% (7.4% to 38.0%), and among all DOACs between 2012 and 2019, apixaban was the most commonly prescribed (46.1%). Warfarin use decreased and DOAC use increased in all subgroups, including in compensated and decompensated cirrhosis, thrombocytopenia, coagulopathy, chronic kidney disease/end-stage renal disease, and across CHA2DS2-VASc categories. Among OAC users (2012-2019), DOAC use increased by 58.9% (18.7% to 77.6%). Among DOAC users, the greatest proportional increase was with apixaban (61.2%; P<0.001). Conclusions Among US patients with cirrhosis and NVAF, DOAC use has increased substantially and surpassed warfarin, including in decompensated cirrhosis. Nevertheless, >55% of patients remain untreated, underscoring the need for clearer treatment guidance.

Effectiveness and Safety of Dabigatran in Atrial Fibrillation Patients with Severe Obesity: a Real-World Retrospective Cohort Study

BACKGROUND

Direct oral anticoagulants such as dabigatran are the preferred anticoagulant in treating atrial fibrillation (AF) patients due to their effectiveness and safety. Whether this applies to severely obese patients needs to be determined.

OBJECTIVE

To compare the effectiveness and safety of dabigatran with warfarin among AF patients with severe obesity.

DESIGN

Retrospective cohort study.

PARTICIPANTS

AF patients with a BMI >40kg/m2 or a weight >120kg receiving dabigatran or warfarin between 10/01/2010 and 12/31/2019 in a large integrated health system and followed through 08/01/2020.

INTERVENTIONS

Not applicable.

MAIN MEASURES

Primary effectiveness outcome was composite thromboembolism including transient ischemic attack, ischemic stroke, or systemic embolism. Primary safety outcome was composite bleeding including gastrointestinal bleeding, intracranial bleeding, or other bleeding. Secondary outcomes included the individual outcomes and all-cause mortality. Propensity score matching (PSM) was performed to create a 1:1 matched cohort and Cox proportional hazards model was used to estimate the hazard ratio (HR) of each outcome for dabigatran users compared to warfarin users.

KEY RESULTS

A total of 6848 patients receiving either dabigatran or warfarin were identified. In a 1:1 matched cohort, dabigatran users had a HR of 0.71 (95% confidence interval (CI): 0.56-0.91) for composite thromboembolism, a HR of 1.24 (95%CI: 1.07-1.42) for composite bleeding, and a HR of 0.57 (95% CI: 0.45-0.71) for all-cause mortality when compared to warfarin users.

CONCLUSIONS

Among AF patients with a BMI >40kg/m2 or a weight >120kg in a real-world clinical setting, dabigatran was effective in reducing the risk of thromboembolism and mortality but was associated with an increased risk of bleeding when compared to warfarin. Dabigatran may be a reasonable option for AF patients with severe obesity.

Stroke Prevention in Atrial Fibrillation: A Scientific Statement of JACC: Asia (Part 2)

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with substantial increases in the risk for stroke and systemic thromboembolism. With the successful introduction of the first non-vitamin K antagonistdirect oral anticoagulant agent (NOAC) in 2009, the role of vitamin K antagonists has been replaced in most clinical settings except in a few conditions for which NOACs are contraindicated. Data for the use of NOACs in different clinical scenarios have been accumulating in the past decade, and a more sophisticated strategy for patients with AF is now warranted. JACC: Asia recently appointed a working group to summarize the most updated information regarding stroke prevention in AF. The aim of this statement is to provide possible treatment options in daily practice. Local availability, cost, and patient comorbidities should also be considered. Final decisions may still need to be individualized and based on clinicians' discretion. This is part 2 of the statement.

Using a Simple Prescription Gap to Determine Warfarin Discontinuation Can Lead to Substantial Misclassification

BACKGROUND

Warfarin remains widely used and a key comparator in studies of other direct oral anticoagulants. As longer-than-needed warfarin prescriptions are often provided to allow for dosing adjustments according to international normalized ratios (INRs), the common practice of using a short allowable gap between dispensings to define warfarin discontinuation may lead to substantial misclassification of warfarin exposure. We aimed to quantify such misclassification and determine the optimal algorithm to define warfarin discontinuation.

METHODS

We linked Medicare claims data from 2007 to 2014 with a multicenter electronic health records system. The study cohort comprised patients ≥65 years with atrial fibrillation and venous thromboembolism initiating warfarin. We compared results when defining warfarin discontinuation by (1) different gaps (3, 7, 14, 30, and 60 days) between dispensings and (2) having a gap ≤60 days or bridging larger gaps if there was INR ordering at least every 42 days (60_INR). Discontinuation was considered misclassified if there was an INR ≥2 within 7 days after the discontinuation date.

RESULTS

Among 3,229 patients, a shorter gap resulted in a shorter mean follow-up time (82, 95, 117, 159, 196, and 259 days for gaps of 3, 7, 14, 30, 60, and 60_INR, respectively; p < 0.001). Incorporating INR (60_INR) can reduce misclassification of warfarin discontinuation from 68 to 4% (p < 0.001). The on-treatment risk estimation of clinical endpoints varied significantly by discontinuation definitions.

CONCLUSION

Using a short gap between warfarin dispensings to define discontinuation may lead to substantial misclassification, which can be improved by incorporating intervening INR codes.

Major Bleeding Risk in Patients With Non-valvular Atrial Fibrillation Concurrently Taking Direct Oral Anticoagulants and Antidepressants

Direct oral anticoagulants (DOACs) are commonly prescribed with antidepressants that may increase bleeding risk. Here we assessed the association between DOACs with and without concurrent antidepressants and major bleeding risk in patients with atrial fibrillation (AF) by a retrospective cohort study included patients with AF who received prescriptions of DOACs in Taiwan’s National Health Insurance database between 2012 and 2017. Adjusted rate ratio (ARR) of major bleeding was calculated by comparing incidence rate adjusted with Poisson regression and inverse probability of treatment weighting using the propensity score between patient-times with and without antidepressants. Among 98863 patients with AF, concurrent use of bupropion with DOACs increased the risks of all major bleeding (ARR: 1.49, 95% CI: 1.02–2.16) and gastrointestinal hemorrhage (ARR: 1.57, 95% CI: 1.04–2.33). An increased risk of intracerebral hemorrhage (ICH) was associated with the combinations of DOACs with selective serotonin reuptake inhibitors (SSRIs, ARR: 1.38, 95% CI: 1.08–1.76), particularly in paroxetine (ARR: 2.11, 95% CI: 1.17–3.81), and tetracyclic antidepressants (TeCAs, ARR: 1.34, 95% CI: 1.01–1.78). In subgroup analyses stratified by individual NOACs, SSRIs increased the risk of ICH in the dabigatran-treated patients (ARR: 1.55, 95% CI: 1.04–2.33). The combinations of apixaban and serotonin-norepinephrine reuptake inhibitors (SNRIs) were associated with a higher risk of all major bleeding (ARR: 1.63, 95% CI: 1.04–2.55). These results clearly indicate the drug–drug interactions between DOACs and antidepressants, which should be carefully considered when prescribing DOACs in adult patients. Careful monitoring for bleeding should be performed while concurrently prescribing DOACs with bupropion, SSRI, SNRI, and TeCA. Concomitant use of DOACs and TCAs may be a relatively safe strategy for patients with AF.

Patient perception and treatment convenience of dabigatran versus vitamin K antagonist when used for stroke prophylaxis in atrial fibrillation: Real-world Evaluation of Long-term Anticoagulant Treatment Experience (RE-LATE) study

Purpose

Dabigatran is a direct thrombin inhibitor approved for stroke prophylaxis in patients with non-valvular atrial fibrillation (NVAF). Real-world data about patient preference, satisfaction and convenience in patients in Asia are not available. The study aimed to explore the perception of patients with newly diagnosed NVAF regarding dabigatran versus vitamin K antagonists (VKAs), when used for stroke prevention.

Patients and methods

This was a multinational, multicentre, non-interventional study involving 49 sites across 5 countries in South East Asia and South Korea where 934 patients newly diagnosed with NVAF were initiated on either dabigatran (N=591) or VKA (N=343). Data were collected at baseline and over two follow-up visits across 6 months. Treatment satisfaction and patient convenience were evaluated using the Perception on Anticoagulant Treatment Questionnaire-2 (PACT-Q2).

Results

The mean age of the patients was 65.9±10.4 years, and 64.2% were male. Mean CHA₂DS₂-VASc score was 2.4±1.5, and mean HAS-BLED score was 1.2±0.9. At baseline, patients initiated on dabigatran had higher stroke risk, bleeding risk, creatinine clearance and proportion of patients with concomitant illnesses compared with patients initiated on VKAs. Treatment convenience was perceived to be significantly better with dabigatran versus VKAs at visits 2 and 3 (p=0.0423 and 0.0287, respectively). Treatment satisfaction was significantly better with dabigatran compared with VKAs at visit 3 (p=0.0300).

Conclusion

In this study, dabigatran is associated with better patient perception in terms of treatment convenience and satisfaction compared with VKAs when used for stroke prevention in newly diagnosed NVAF patients from South East Asia and South Korea.

Trial registration number

NCT02849509.

Plain language summary

Patient satisfaction with dabigatran versus VKAs in South East Asia. Patients with atrial fibrillation are at high risk of stroke and require anticoagulants for stroke prevention. Two such anticoagulants are dabigatran and VKAs. We wanted to compare the extent of satisfaction and treatment convenience among newly diagnosed patients with atrial fibrillation from the South East Asian region when they were given either dabigatran or VKAs. Consenting patients filled out a standardised questionnaire called the PACT-Q2 over three visits after they were started on either dabigatran (591 patients) or VKAs (343 patients). We found that satisfaction and convenience were significantly higher when patients received dabigatran than when they received VKAs.

Oral Anticoagulation Timing in Patients with Acute Ischaemic Stroke and Atrial Fibrillation

BACKGROUND AND PURPOSE

Oral anticoagulants (OACs) prevent stroke recurrence and vascular embolism in patients with acute ischaemic stroke (AIS) and atrial fibrillation (AF). Current guidance recommends a "1-3-6-12 day"' rule to resume OACs after AIS, based mainly on empirical consensus. This study investigated the suitability of guideline-recommended timing for OAC initiation.

METHODS

To overcome immortal time bias, we emulated a sequence of randomized placebo-controlled trials and constructed 90 propensity score-matched cohorts of 12,307 patients with AF and AIS from 2012 to 2016. We compared the risk of composite effectiveness and safety outcome in the early vs no OAC use group and in the delayed vs no OAC use. Indirect comparison between early and delayed use was conducted using a network meta-analysis.

RESULTS

Across the groups of AIS severity, the risks of composite outcome or effectiveness outcome were lower in the OAC use group than the no use group and the risks were similar between the early and delayed use groups. In patients with severe AIS, those receiving early OACs use had an increased risk of safety outcome, with HR of 2.10 (CI: 1.13-3.92) compared with those without OAC use, and HR of 1·44 (CI: 0·99-2·09) compared with those receiving delayed use.

CONCLUSIONS

In AF patients with severe AIS, early OAC use before the guideline-recommended days appeared to increase the risk of bleeding events, although the OAC initiation time seemed not to affect the risk of serious vascular events. The optimal severity-specific timing for OAC initiation after AIS requires further evaluation.

Effects of rivaroxaban and warfarin on the risk of gastrointestinal bleeding and intracranial hemorrhage in patients with atrial fibrillation: Systematic review and meta-analysis

To assess the risk of gastrointestinal bleeding and intracranial hemorrhage in patients with atrial fibrillation (AF) after the use of rivaroxaban or warfarin. To investigate the effects of rivaroxaban and warfarin on gastrointestinal and intracranial hemorrhage in patients with AF, we searched PubMed, Embase, and Medline from the establishment of databases up to 2020. We finally included 38 observational studies involving 1 312 609 patients for the assessment of intracranial hemorrhage, and 33 observational studies involving 1 332 956 patients for the assessment of gastrointestinal bleeding. The rates of intracranial hemorrhage were 0.55% in the rivaroxaban group versus 0.91% in the warfarin group (OR 0.59; 95% CI 0.53-0.66; p < .00001, I2 = 78%). The rates of gastrointestinal bleeding were 2.63% in patients with rivaroxaban versus 2.48% in those with warfarin (OR 1.06; 95% CI 0.96-1.17; p < .00001, I2 = 94%). Rivaroxaban could significantly reduce the risk of intracranial hemorrhage in patients with AF than warfarin, but the risk of gastrointestinal bleeding remained controversy due to no statistical significant difference. Notably, a subgroup analysis demonstrated that patients in rivaroxaban group with severe chronic renal diseases or undergoing hemodialysis exposed to less gastrointestinal hemorrhage risk than the group from warfarin.

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).

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.

Risk of recurrent stroke for Asian stroke patients treated with non-vitamin K antagonist oral anticoagulant and warfarin

Aim:

The aim of this study was to establish whether non-vitamin K antagonist oral anticoagulants (NOACs) are superior to warfarin in preventing stroke recurrence for atrial fibrillation (AF) patients with an ischemic or hemorrhagic stroke at the baseline.

Methods:

From 1 January 2009 to 31 December 2017, stroke patients with AF treated with oral anticoagulants in the National Health Insurance Research Database in Taiwan were enrolled. The study was retrospective cohort design. Outcome measures were ischemic and hemorrhagic stroke recurrence. The Cox proportional hazard model was used to obtain the hazard ratio (HR).

Results:

In total, 39,840 stroke patients with AF treated with NOAC and 42,583 treated with warfarin were identified. NOACs were superior to warfarin in preventing all recurrent stroke [adjusted HR: 0.67, 95% confidence interval (CI), 0.63–0.71, p < 0.001]. Results for the ischemic stroke population were the same as that for all types for stroke (adjusted HR: 0.66, 95% CI, 0.62–0.70, p < 0.001). For the hemorrhagic stroke population, NOACs were equivalent to warfarin in preventing ischemic stroke (adjusted HR: 1.11, 95% CI, 0.86–0.43, p < 0.001), but NOACs were superior to warfarin in preventing hemorrhagic stroke (adjusted HR: 0.64, 95% CI, 0.55–0.74, p < 0.001).

Conclusions:

NOACs were generally superior to warfarin in terms of efficacy and safety in previous stroke patients. The robustness of our findings was verified and should add new information to current recommendations for Asian stroke patients in selecting NOACs.

Practice-derived data on non-vitamin K antagonist oral anticoagulant therapy to complement observations from randomized trials

Anticoagulation is fundamental in the management of patients with atrial fibrillation (AF). The study aims to provide a comparative review of the major phase III randomized clinical trials (RCTs) and real-world data (RWD) from reliable, high-grade Phase IV studies that assess the efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOACs) vs. vitamin K antagonists (VKAs). Observational studies based on nationwide or health insurance database records on the use of NOACs vs. VKAs in patients with AF were included. We performed a comparison of the efficacy and safety characteristics associated with NOACs vs. VKAs in RCTs and RWD. Although RCTs provide strong support for evidence-based practice, RWD may be used to reflect the broader picture of various clinical settings, provide supplementary insight and fulfil knowledge gaps. Both study types confirmed the safety and efficacy of NOACs in preventing stroke and thromboembolism in patients with AF. In comparison to VKAs, NOACs were associated with reduced risk of ischaemic events and lower rates of adverse events such as major bleeding or intracranial haemorrhage. Administration of NOACs might be associated with increased risk of dose-related gastrointestinal bleeding and myocardial ischaemic events, especially in the early treatment period after switching from VKAs. Special care should be taken in challenging clinical situations like severe renal or hepatic impairment when the treatment regimen needs to be considered individually. Randomized clinical trial and RWD studies are complementary and present comparable findings, affirming that NOACs are safe and effective for anticoagulation of patients with AF in daily clinical practice.

Comparison of Long-Term Outcomes Between Combination Antiplatelet and Anticoagulant Therapy and Anticoagulant Monotherapy in Patients With Atrial Fibrillation and Left Atrial Thrombi

Background: Anticoagulation for patients with atrial fibrillation (AF) complicated by left atrial thrombi (LAT) is a frequent cause of bleeding complications, but risk factors remain unknown.

Methods and Results: Of 3,139 AF patients who underwent transesophageal echocardiography, 82 with LAT under anticoagulation were included in this study. Patients treated with combination antiplatelet and anticoagulant therapy (n=31) were compared with those receiving anticoagulant monotherapy (n=51) to investigate the effects of antiplatelet agents during anticoagulation on bleeding complications. Over a mean (±SD) follow-up of 878±486 days, bleeding events occurred more frequently in the combination therapy than monotherapy group (58% vs. 20%; P<0.001), but there was no significant difference in embolic events (6.5% vs. 3.9%; P=0.606). Kaplan-Meier analysis also showed a significantly higher rate of bleeding events in the combination therapy group, but no significant difference in the rate of embolic events. Inverse probability of treatment weighting revealed that combination therapy was independently associated with an increased risk of bleeding (hazard ratio [HR] 2.98, 95% confidence interval [CI] 1.14–7.89, P=0.026), but not with the risk of embolic events (HR 0.30, 95% CI 0.04–2.59, P=0.275). Net clinical benefit analysis was almost negative for combination therapy vs. monotherapy.

Conclusions: In patients with AF and LAT, combination therapy was significantly associated with an increased risk of bleeding events, but not with a reduced risk of embolic events.

Effectiveness and Safety of Non-Vitamin K Antagonist Oral Anticoagulant and Warfarin in Cirrhotic Patients With Nonvalvular Atrial Fibrillation

Background

Liver cirrhotic patients with nonvalvular atrial fibrillation have been excluded from randomized clinical studies regarding oral anticoagulants for stroke prevention. Whether non–vitamin K antagonist oral anticoagulants (NOACs) are superior to warfarin for these patients remains unclear.

Methods and Results

This nationwide retrospective cohort study, with data collected from the Taiwan National Health Insurance Research Database, enrolled 2428 liver cirrhotic patients with nonvalvular atrial fibrillation taking apixaban (n=171), dabigatran (n=535), rivaroxaban (n=732), or warfarin (n=990) from June 1, 2012, to December 31, 2016. We used propensity score–based stabilized weights to balance covariates across study groups. Patients were followed until the occurrence of an event or the end date of study. The NOAC group (n=1438) showed risk of ischemic stroke/systemic embolism and intracranial hemorrhage comparable to that of the warfarin group (n=990) after adjustment. The NOAC group showed significantly lower risk of gastrointestinal bleeding (hazard ratio: 0.51 [95% CI, 0.32–0.79]; P=0.0030) and all major bleeding (hazard ratio: 0.51 [95% CI, 0.32–0.74]; P=0.0003) compared with warfarin group. Overall, 90% (n=1290) of patients were taking a low‐dose NOAC (apixaban 2.5 mg twice daily, rivaroxaban 10–15 mg daily, or dabigatran 110 mg twice daily). The subgroup analysis indicated that both dabigatran and rivaroxaban showed lower risk of all major bleeding than warfarin. The advantage of lower gastrointestinal and all major bleeding with NOACs over warfarin is contributed by those subgroups with either nonalcoholic or nonadvanced liver cirrhosis.

Conclusions

NOACs have a risk of thromboembolism comparable to that of warfarin and a lower risk of major bleeding among liver cirrhotic Asian patients with nonvalvular atrial fibrillation. Consequently, thromboprophylaxis with low‐dose NOACs may be considered for such patients.

See Editorial by Gallagher et al

Major bleeding risk associated with oral anticoagulant in real clinical practice. A multicentre 3-year period population-based prospective cohort study

AIMS

The objective was to compare major bleeding risk of direct oral anticoagulants (DOACs; per type and dose) with vitamin K antagonists (VKAs), irrespective of indication, using real-world data.

METHODS

A population-based prospective cohort study, using the French national health data system (SNIIRAM), identified 47 469 adults living within 5 well-defined geographical areas, who were new users of oral anticoagulants in the period 2013-2015: 20 205 VKA users, 19 579 rivaroxaban users, 4225 dabigatran users and 3460 apixaban users. From all emergency departments within these areas, clinical data for all adults referred for bleeding was collected and medically validated. The databases were linked for common key variables. The main outcome measure was major bleeding: intracranial haemorrhage, major gastrointestinal bleeding and other major bleeding events. Hazard ratios were derived from adjusted Cox proportional hazard models. We used propensity score weighting as a sensitivity analysis, with separate analyses according to indications (atrial fibrillation or venous thromboembolism).

RESULTS

Compared to VKAs, high and low-dose DOACs were associated with a reduced risk of intracranial haemorrhage (adjusted hazard ratio 0.55, 95% confidence interval 0.37-0.82 and 0.54, 0.26-1.12 respectively), and a reduced risk of other major bleeding events (0.41, 0.29-0.58 and 0.41, 0.22-0.79 respectively), irrespective of duration and indication. Neither DOAC dose evidenced any significant difference from VKAs in terms of risk of major gastrointestinal bleeding.

CONCLUSION

There is a clear benefit of using DOACs with regard to intracranial haemorrhage. The study provides new insight into major gastrointestinal and other major bleeding events.

Comparative effectiveness and safety of oral anticoagulants for atrial fibrillation: A retrospective cohort study

Oral anticoagulants (OACs) are high-priority medications, frequently used with clinically important benefit and serious harm. Our objective was to compare the safety and effectiveness of direct-acting oral anticoagulants (DOACs) versus warfarin in a population where anticoagulation management and DOACs were readily available. A retrospective cohort study of all adults living in British Columbia with a diagnosis of atrial fibrillation and a first prescription for an OAC was conducted. Co-primary outcomes were ischemic stroke and systemic embolism, and major bleeding. Secondary outcomes included a net clinical outcome composite and analysis of discontinuation, switching, and key subgroups. We estimated the effects of treatment using time-to-event models with high-dimensional propensity score adjustment to control confounding. After adjustment for prescribing bias, a cohort (n = 20,113, 43.8% female, mean age 72.4 years) with a mean follow-up of 18.1 months showed that patients taking warfarin tended to be poorer, sicker, and less likely to have a cardiologist prescriber. Outcome event rates were not significantly different for DOACs compared to warfarin [adjusted rate ratio of 1.15 (0.91, 1.46) for systemic embolism, 0.94 (0.82, 1.08) for major bleeding, and 0.98 (0.90, 1.06) for net clinical outcome]. Only the effect of age on net clinical outcome met our strict criteria for predicting which group might be superior. Switch of drug class was associated with increased risk of events (p < 0.003). In this population, we found no difference in important clinical outcomes between warfarin and DOACs. Switching compared to not switching was associated with harm.

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.

Peripheral leukocyte count and risk of bleeding in patients with non-valvular atrial fibrillation taking dabigatran: a real-world study

BACKGROUND

The association between peripheral leukocyte count and bleeding events in nonvalvular atrial fibrillation (NVAF) patients treated with dabigatran remains unclear. This study aimed to explore the association between leukocyte count and bleeding events after excluding other confounders in NVAF patients taking dabigatran.

METHODS

A total of 851 NVAF patients treated with dabigatran (110 mg bid) were recruited from 12 centers in China from February 2015 to December 2017. Follow-up was completed by May 2018. The exposure and outcome variables were leukocyte count measured at baseline and the number of bleeding events within the subsequent 6 months. Multivariate Cox proportional hazards models were constructed to analyze independent associations, and a Cox proportional hazards regression with cubic spline functions and smooth curve fitting (penalized spline method) was used to address nonlinearity between leukocyte count and bleeding. The inflection point was calculated using a recursive algorithm, and then a two-piecewise Cox proportional hazards model for both sides of the inflection point was constructed.

RESULTS

During 6-month follow-up, 87 participants occurred bleeding events. For every 1 × 10/L increase in leukocyte count, the risk of bleeding increased by 11% (hazard ratio [HR]: 1.11, 95% confidence interval [CI]: 0.99-1.25). The smooth curve showed nonlinear relationship between leukocyte count and bleeding events. The inflection point of the leukocyte count was 6.75 × 10/L. For leukocyte counts < 6.75 × 10/L, the HR (95% CI) was 0.88 (0.69-1.13), and for leukocyte counts ≥ 6.75 × 10/L, the HR (95% CI) was 1.28 (1.09-1.51).

CONCLUSION

This study found a J-shaped association between baseline leukocyte count and risk of bleeding in NVAF patients treated with dabigatran.

CLINICAL TRIAL REGISTRATION

NCT02414035, https://clinicaltrials.gov.

Effectiveness and Safety of Direct Oral Anticoagulants in Relation to Temporal Changes in Their Use

Background:

Since the direct oral anticoagulants (DOAC) were introduced, oral anticoagulant (OAC) prescription patterns have rapidly changed in patients with atrial fibrillation (AF). We aimed to evaluate the evolving trends of OAC use in a large nationwide cohort and specifically examine the changes in patient profiles treated with warfarin or DOAC and whether the time trends in OAC use affected clinical outcomes.

Methods and Results:

Using the Korean Health Insurance Review and Assessment database, we divided OAC naive patients with AF into 3 groups according to the enrollment period between January 2015 and December 2017 (n=35 353 in cohort 1, n=36 631 in cohort 2, and n=44 819 in cohort 3). DOAC use increased from 59% to 89%, whereas warfarin use has decreased from 41% to 11% during the study period. Patients treated with warfarin were increasingly younger from cohort 1 to cohort 3 (mean age 68–65 years, P <0.001) with lower mean CHA 2 DS 2 -VASc scores (3.3–2.9, P <0.001), whereas those with DOAC did not show a significant difference in clinical characteristics over the study period. Warfarin group had improved clinical outcomes over time, reflecting dynamic changes in patient characteristics. Compared with warfarin group, unadjusted hazard ratios of composite outcome for DOAC group have changed over time (hazard ratio 0.77 [95% CI, 0.69–0.85] in cohort 1, hazard ratio 0.84 [95% CI, 0.73–0.97] in cohort 2, and hazard ratio 1.00 [95% CI, 0.78–1.25] in cohort 3). After propensity score weighting between warfarin and DOAC groups in each cohort, DOAC showed consistently lower risks of the composite outcome by approximately 23% to 25% compared with warfarin across 3 different periods.

Conclusions:

In contemporary clinical practice, OAC prescription patterns and characteristics of patients treated warfarin or DOAC have dynamically changed. Despite these changes, DOAC showed a consistent better net clinical benefit compared with warfarin across different periods.

Effectiveness and Safety of Off-label Dosing of Non-vitamin K Antagonist Anticoagulant for Atrial Fibrillation in Asian Patients

Non–vitamin K antagonist anticoagulants (NOACs) have been used to prevent thromboembolism in patients with atrial fibrillation (AF) and shown favorable clinical outcomes compared with warfarin. However, off-label use of NOACs is frequent in practice, and its clinical results are inconsistent. Furthermore, the quality of anticoagulation available with warfarin is often suboptimal and even inaccurate in real-world data. We have therefore compared the effectiveness and safety of off-label use of NOACs with those of warfarin whose anticoagulant intensity was accurately estimated. We retrospectively analyzed data from 2,659 and 3,733 AF patients at a tertiary referral center who were prescribed warfarin and NOACs, respectively, between 2013 and 2018. NOACs were used at off-label doses in 27% of the NOAC patients. After adjusting for significant covariates, underdosed NOAC (off-label use of the reduced dose) was associated with a 2.5-times increased risk of thromboembolism compared with warfarin, and overdosed NOAC (off-label use of the standard dose) showed no significant difference in either thromboembolism or major bleeding compared with warfarin. Well-controlled warfarin (TTR ≥ 60%) reduced both thromboembolism and bleeding events. In conclusion, the effectiveness of NOACs was decreased by off-label use of the reduced dose.

Using non-vitamin K oral anticoagulants in specific patient populations: a study of Korean cases

Non-vitamin K oral anticoagulants (NOACs) are increasingly used as alternatives to conventional therapies and have considerable accumulated real-world clinical data in patients with non-valvular atrial fibrillation (NVAF) or venous thromboembolism (VTE). However, it is not easy to make a complete changeover to NOACs in real-world clinical practice because NOACs still have challenges in specific patient populations (eg, Asian patients, NVAF patients presenting with acute coronary syndrome [ACS], dialysis patients with NVAF, patients with cancer-associated VTE, etc.). Clinical data on the optimal dose of NOACs in Asian patients with NVAF are not sufficient. The intensity of NOAC and antiplatelet treatment and the duration of antiplatelet treatment should be adjusted according to the bleeding and thrombotic risk profiles of the individual NVAF patient presenting with ACS. Increased bleeding risk and unclear efficacy of NOACs in dialysis patients with NVAF should be considered when making decisions on whether to give NOACs for these patients. If dialysis patients with NVAF require anticoagulant for stroke prevention, then apixaban could be considered while awaiting more clinical efficacy and safety data. Additional studies are needed to determine the utility of continuing treatment with reduced-dose NOACs for long-term therapy after VTE. We have enough experiences in using NOACs in cancer patients showing the benefit of antithrombotic treatment counterbalanced the bleeding risk; however, some challenges of cancer-associated VTE management exist due to differences in cancer types or chemotherapy regimens and comorbidities. Different dosing regimens among NOACs may impact on medication adherence; thus, individual patient preference should be considered in choosing a particular NOAC. A significant proportion of patients remain on warfarin because of the high price of NOACs and variability in reimbursement coverage. To compensate clinical-evidence and achieve optimal use of NOACs, we should pay attention to the outcomes of ongoing studies and evaluate more real-world data.

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.

Re-evaluating Safety and Effectiveness of Dabigatran Versus Warfarin in a Nationwide Data Environment: A Prevalent New-User Design Study

Introduction

The new user cohort design is widely used to assess the effects of a new drug, such as dabigatran, but inherently excludes some users due to prior use of the comparator drug, for example warfarin. The prevalent new-user design offers a solution that includes all eligible users of the new drug.

Objective

To evaluate the safety and effectiveness of dabigatran versus warfarin in non-valvular atrial fibrillation (NVAF) patients with prevalent new-user design.

Methods

Taiwan National Health Insurance and mortality data from 2011 through 2015 were utilized. From an incident NVAF cohort, we identified dabigatran initiators as either incident or prevalent (switchers from warfarin) new users. Time- and prescription-based exposure sets were formed for dabigatran initiators to account for prior warfarin prescriptions. A comparable warfarin user was matched on the time-conditional propensity score to the dabigatran initiator in each set. The matched patients were followed for clinical outcomes, with Cox proportional hazards model used to estimate hazard ratios (HRs).

Results

There were 10,811 dabigatran initiators, including 22% prevalent new users (switchers), who formed the exposure sets and were matched 1:1 to warfarin users. Dabigatran use was associated with lower risks of intracranial hemorrhage (HR 0.51; 95% confidence interval [CI] 0.39, 0.66) and gastrointestinal bleeding (HR 0.81; 95% CI 0.70, 0.92), compared with warfarin use. These effects were similar between the incident and prevalent new users.

Conclusion

Using a design that includes both incident and prevalent new users of dabigatran, the use of dabigatran is associated with lower major bleeding risk than warfarin use among patients with incident NVAF.

Electronic supplementary material

The online version of this article (10.1007/s40801-019-0156-2) contains supplementary material, which is available to authorized users.

Effectiveness and Safety of Direct Oral Anticoagulants versus Vitamin K Antagonists for People Aged 75 Years and over with Atrial Fibrillation: A Systematic Review and Meta-Analyses of Observational Studies

Older people, are underrepresented in randomised controlled trials of direct oral anticoagulants (DOACs) for stroke prevention in atrial fibrillation (AF). The aim of this study was to combine data from observational studies to provide evidence for the treatment of people aged ≥75 years. Medline, Embase, Scopus and Web of Science were searched. The primary effectiveness outcome was ischaemic stroke. Safety outcomes were major bleeding, intracranial haemorrhage, gastrointestinal bleeding, myocardial infarction, and mortality. Twenty-two studies were eligible for inclusion. Two studies related specifically to people ≥75 years but were excluded from meta-analysis due to low quality; all data in the meta-analyses were from subgroups. The pooled risk estimate of ischaemic stroke was slightly lower for DOACs. There was no significant difference in major bleeding, mortality, or myocardial infarction. Risk of intracranial haemorrhage was 44% lower with DOACs, but risk of GI bleeding was 46% higher. Our results suggest that DOACs may be preferable for the majority of older patients with AF, provided they are not at significant risk of a GI bleed. However, these results are based entirely on data from subgroup analyses so should be interpreted cautiously. There is a need for adequately powered research in this patient group.

Recurrent ischemic stroke in atrial fibrillation with non-vitamin K antagonist oral anticoagulation

The etiology or rate of recurrent ischemic stroke according to dosing methods including drug adherence in patients taking non-vitamin K antagonist oral anticoagulants (NOACs) remain uncertain. We investigated the association between dosing methods including drug adherence achieved with NOACs and the presence of major vessel occlusion (MVO) in patients with ischemic stroke with non-valvular atrial fibrillation (NVAF). From July 2013 through December 2016, 120 patients with recurrent ischemic stroke with NVAF on NOACs were retrospectively analyzed. Patients taking non-standard doses of NOACs were divided into the missed dose group that discontinued NOACs for ≥48 h prior to arrival, and the under-dose group that used lower doses of NOACs. A logistic regression analysis was performed to determine the association between MVO and dosing methods including drug adherence. There were 60 (50.0%), 39 (32.5%), and 21 (17.5%) patients, respectively, in the standard dose, under-dose, and missed dose groups. Twelve patients (20.0%) in the standard dose group, 15 (38.5%) in the under-dose group, and 13 (61.9%) in the missed dose group had MVO. MVO was significantly higher in the missed dose group than in the standard dose and under-dose groups (P = 0.002). In patients with ischemic stroke with NVAF, who are on NOACs, anticoagulation caused by missed or lowered doses of NOACs was significantly associated with MVO in patients with recurrent cardioembolic stroke.

Stroke Risk Status, Anticoagulation Treatment, and Quality-of-Life in Chinese Patients with Atrial Fibrillation: China Registry of Atrial Fibrillation (CRAF)

Objective. To investigate the contemporary status of stroke risk profile, antithrombotic treatment, and quality-of-life (QoL) of patients with all types of atrial fibrillation (AF) in China. Design. This is a multicenter, cross-sectional study. Setting. Tertiary (80%) and Tier 2 hospitals (20%) were identified in different economic regions (Northeast, East, West, and Middle) by using a simple random sampling. Participants. A total of 3562 (85.6%) patients with nonvalvular atrial fibrillation (NVAF) and 599 (14.4%) with rheumatic valvular atrial fibrillation (VAF) were consecutively enrolled from 111 hospitals from July 2012 to December 2012. Data Collection. Patient information was collected and QoL was assessed using Short-Form 36 Health Survey (SF-36) questionnaire. Primary and Secondary Outcome Measures. The risk of stroke was assessed using the CHADS₂ and CHA₂DS₂-VASc. QoL was assessed using Medical Outcomes Study SF-36 questionnaire. Results. Overall, 31.7% of the patients received anticoagulant treatment and 61.2% received antiplatelet treatment. The rate of anticoagulant treatment was higher in patients with VAF than in those with NVAF. The anticoagulant use was the lowest in Northeast and the highest in Middle regions. Independent risk factors associated with underuse of anticoagulants for NVAF were age, systolic blood pressure (SBP), non-Middle regions, nontertiary hospitals, and new-onset or paroxysmal AF. For VAF patients, the independent factors were age, paroxysmal AF, treatment in Tier 2 hospitals, SBP, diastolic blood pressure, history of coronary artery disease, and nonreceipt of antiarrhythmic therapy. Patients receiving anticoagulants fared significantly better in some QoL domains than those who received no antithrombotic therapy. Conclusions. These findings suggest that antiplatelet treatment is overused and anticoagulant treatment is underused both in Chinese patients with VAF and NVAF, even though usage of anticoagulants is associated with better QoL. Risk factors with underuse of anticoagulants were not identical in patients with NVAF and VAF.

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

Antithrombotic Treatment May Reduce Mortality Among New-Onset Atrial Fibrillation Patients with Gray-Zone Risk of Stroke

In clinical practice, some atrial fibrillation (AF) patients were classified as having low and moderate stroke risk by the CHADS₂ score (≤ 1) in 2001 but in 2012 they were not truly classified as low risk of stroke according to the CHA₂DS₂-VASc score (≥ 2) (defined gray zone). Therefore, a treatment gap exists in gray zone AF patients. This study aimed to evaluate whether gray zone AF patients could benefit from reduced all-cause mortality under antithrombotic treatment. This was a longitudinal cohort study performed using data from claim forms submitted to the Taiwan Bureau of National Health Insurance from January 2000 to December 2011. The new-onset AF patients consisted of a gray zone cohort with a total of 1237 patients being enrolled. The primary outcome was all-cause mortality between 2001 and 2011. Patients in the gray zone receiving antithrombotic treatment had a significant reduction in all-cause mortality [hazard ratio (HR): 0.21; 95% confidence interval (CI): 0.16-0.28] compared with the no treatment group [warfarin only: HR, 0.28 (95% CI, 0.15-0.52); warfarin + Aspirin: HR, 0.21 (95% CI, 0.15-0.30); and Aspirin only: HR, 0.22 (95% CI, 0.16-0.29) ]. All-cause mortality was notably increased when any of the following risk factors were present: age 65-74 years, age ≥ 75 years, chronic kidney disease, and vascular disease. We concluded that AF patients in the gray zone must receive either anticoagulant and/or antiplatelet treatment and there is a lower mortality in these groups during long-term follow-up. Further investigation is needed to observe whether the antithrombotic drugs have benefits for patients with AF with a CHA₂DS₂-VASc score < 2.

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 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.

Optimal dose of dabigatran for the prevention of thromboembolism with minimal bleeding risk in Korean patients with atrial fibrillation

Aims

We aim to determine the optimal dose of dabigatran in Korean patients with atrial fibrillation (AF).

Methods and results

We analysed 1834 patients with non-valvular AF, classified into a warfarin group (n = 990), dabigatran 150 mg group (D150, n = 294), and 110 mg group (D110, n = 550). The D110 group was further classified into patients concordant (co-D110, n = 367) and patients discordant (di-D110, n = 183) with guidelines to dose reduction. Propensity-matched 1-year clinical outcomes were then compared. Efficacy outcomes were defined as thromboembolism composed of new-onset stroke or systemic embolism. Safety outcomes were major bleeding. Both D150 and D110 had comparable efficacies as warfarin. However, only D110 significantly lowered the risk of major bleeding [hazard ratio (HR) 0.19, 95% confidence interval (CI) 0.07-0.55, P = 0.002]. In a subgroup analysis according to guideline-concordant indications for dose reduction, both co-D110 and di-D110 displayed a comparable efficacy as warfarin. Both co-D110 (HR 0.22, 95% CI 0.06-0.76, P = 0.017) and di-D110 (HR 0.11, 95% CI 0.02-0.81, P = 0.030) significantly lowered incidences of major bleeding. There were no differences in the efficacy and safety between di-D110 and D150, and net clinical outcomes were similar.

Conclusion

Although D150 and D110 had a comparable efficacy, only D110 lowered the risk of major bleeding in Korean AF patients compared with warfarin. Even the guideline-discordant use of dabigatran 110 mg demonstrated a similar efficacy and safety compared with D150. However, further prospective randomized trials are needed in order to comprehensively evaluate whether D150 or D110 is the optimal dosage in Asian patients with AF.

Fitting the right non-vitamin K antagonist oral anticoagulant to the right patient with non-valvular atrial fibrillation: an evidence-based choice

Atrial fibrillation (AF) is the most prevalent arrhythmia and is associated with an increased risk of ischemic stroke (IS) and systemic embolism (SE). Stroke prevention is a key element for the overall management of AF patients. The non-vitamin K antagonist oral anticoagulants (NOACs), such as dabigatran, rivaroxaban, apixaban and edoxaban, are at least as effective as warfarin in reducing IS/SE with a lower rate of major bleeding. Various analyses from the large Phase III randomized trials demonstrated different efficacy and safety of NOACs in specific subgroups of patients. The randomized trials are supplemented by effectiveness and safety data from real-world observational cohorts following the availability of these drugs for use in everyday clinical practice. Given the clinical heterogeneity of AF patients, the available data from trials and real-world studies allow us to fit the right NOAC to the particular patient's characteristics, with the aim of optimizing outcomes for the individual patient. This review article aims to provide a summary of the evidence on the performance of NOACs in AF patients with specific clinical characteristics. Evidence-based suggestions are presented to provide a simple and viable strategy for clinicians for the choice of a particular NOAC. KEY MESSAGE Given the different performance of the new-oral anticoagulants in patients with the different clinical situation, evidence-based choice of fitting the right new-oral anticoagulants to the patients is provided in this review article.

Efficacy and Safety of Apixaban, Dabigatran, Rivaroxaban, and Warfarin in Asians With Nonvalvular Atrial Fibrillation

Background

Whether non–vitamin K antagonist oral anticoagulants (NOACs) are superior to warfarin among Asians with nonvalvular atrial fibrillation remains unclear.

Methods and Results

In this nationwide retrospective cohort study collected from Taiwan National Health Insurance Research Database, there were 5843, 20 079, 27 777, and 19 375 nonvalvular atrial fibrillation patients taking apixaban, dabigatran, rivaroxaban and warfarin, respectively, from June 1, 2012 to December 31, 2016. Propensity‐score weighting was used to balance covariates across study groups. Patients were followed until the first occurrence of any efficacy or safety outcome or the end date of study. Hazard ratios (95% confidence intervals) comparing apixaban, dabigatran, and rivaroxaban with warfarin were: ischemic stroke/systemic embolism (IS/SE), 0.55 (0.43–0.69), 0.82 (0.68–0.98), and 0.81 (0.67–0.97); major bleeding, 0.41 (0.31–0.53), 0.65 (0.53–0.80), and 0.58 (0.46–0.72); and all‐cause mortality, 0.58 (0.51–0.66), 0.61 (0.54–0.68), and 0.57 (0.51–0.65). A total of 3623 (62%), 17 760 (88%), and 26 000 (94%) patients were taking low‐dose apixaban (2.5 mg twice daily), dabigatran (110 mg twice daily), and rivaroxaban (10–15 mg once daily), respectively. Similar to all‐dose NOACs, all low‐dose NOACs had lower risk of IS/SE, major bleeding, and mortality when compared with warfarin. In contrast to other standard‐dose NOACs, apixaban was associated with lower risks of IS/SE (0.45 [0.31–0.65]), major bleeding (0.29 [0.18–0.46]), and mortality (0.23 [0.17–0.31]) than warfarin.

Conclusions

All NOACs were associated with lower risk of IS/SE, major bleeding, and mortality compared with warfarin in the largest real‐world practice among Asians with nonvalvular atrial fibrillation. All low‐dose NOACs had lower risk of IS/SE, major bleeding, and mortality when compared with warfarin. Standard‐dose apixaban caused a lower risk of IS/SE, major bleeding, and mortality compared with warfarin.

Direct Oral Anticoagulants Versus Vitamin K Antagonists in Real-life Patients With Atrial Fibrillation. A Systematic Review and Meta-analysis

INTRODUCTION AND OBJECTIVES

To assess the effectiveness of direct oral anticoagulants vs vitamin K antagonists in real-life patients with atrial fibrillation.

METHODS

A systematic review was performed according to Cochrane methodological standards. The results were reported according to the PRISMA statement. The ROBINS-I tool was used to assess risk of bias.

RESULTS

A total of 27 different studies publishing data in 30 publications were included. In the studies with a follow-up up to 1 year, apixaban (HR, 0.93; 95%CI, 0.71-1.20) and dabigatran (HR, 0.95; 95%CI, 0.80-1.13) did not significantly reduce the risk of ischemic stroke vs warfarin, whereas rivaroxaban significantly reduced this risk (HR, 0.83; 95%CI, 0.73-0.94). Apixaban (HR, 0.66; 95%CI, 0.55-0.80) and dabigatran (HR, 0.83; 95%CI, 0.70-0.97) significantly reduced the major bleeding risk vs warfarin, but not rivaroxaban (HR, 1.02; 95%CI, 0.95-1.10), although with a high statistical heterogeneity among studies. Apixaban (HR, 0.56; 95%CI, 0.42-0.73), dabigatran (HR, 0.45; 95%CI, 0.39-0.51), and rivaroxaban (HR, 0.66; 95%CI, 0.49-0.88) significantly reduced the risk of intracranial bleeding vs warfarin. Reduced doses of direct oral anticoagulants were associated with a slightly better safety profile, but with a marked reduction in stroke prevention effectiveness.

CONCLUSIONS

Data from this meta-analysis suggest that, vs warfarin, the stroke prevention effectiveness and bleeding risk of direct oral anticoagulants may differ in real-life patients with atrial fibrillation.

Continuity of care with physicians and risk of subsequent hospitalization and end-stage renal disease in newly diagnosed type 2 diabetes mellitus patients

Purpose

Effective management for type 2 diabetes mellitus (DM) can slow the progression of kidney outcomes and reduce hospital admissions. Better continuity of care (COC) was found to improve patients’ adherence and self-management. This study examined the associations between COC, hospitalization, and end-stage renal disease (ESRD) in DM patients.

Patients and methods

In the cohort study, data from 1996 to 2012 were retrieved from the Longitudinal Health Insurance Database, using inverse probability weighted analysis. A total of 26,063 patients with newly diagnosed type 2 DM who had been treated with antihyperglycemic agents were included. COC is to assess the extent to which a DM patient visited the same physician during the study period. This study categorized COC into 3 groups – low, intermediate, and high, – according to the distribution of scores in our sample.

Results

The number of ESRD patients in the high, intermediate, and low COC groups were 92 (22.33%), 130 (31.55%), and 190 (46.12%), respectively, and the mean follow-up periods for the 3 groups were 7.13, 7.12, and 7.27 years, respectively. After using inverse probability weighting, the intermediate and low COC groups were significantly associated with an increased risk of ESRD compared with the high COC group (adjusted hazard ratio (aHR) 1.36 [95% CI, 1.03–1.80] and aHR 1.76 [95% CI, 1.35–2.30], respectively). The intermediate and low COC groups were also significantly associated with the subsequent hospitalization compared with the high COC group (aHR 1.15 [95% CI, 0.99–1.33] and aHR 1.72 [95% CI, 1.50–1.97], respectively).

Conclusion

COC is related to ESRD onset and subsequent hospitalization among patients with DM. This study suggested that when DM patients keep visiting the same physician for managing their diseases, the progression of renal disease can be prevented.

Comparative effectiveness of novel oral anticoagulants in UK patients with non-valvular atrial fibrillation and chronic kidney disease: a matched cohort study

OBJECTIVES

To evaluate the effectiveness and safety of novel oral anticoagulants (NOACs) compared with vitamin K antagonists (VKAs) among patients with non-valvular atrial fibrillation (NVAF), particularly those with chronic kidney disease (CKD).

DESIGN

Population-based matched cohort study.

SETTING

Over 670 primary care practices in the UK, contributing to the Clinical Practice Research Datalink.

PARTICIPANTS

Up to 6818 adult patients newly treated with NOACs between 2011 and 2016, matched 1:1 to new users of VKAs on age, sex and high-dimensional propensity score.

INTERVENTIONS

Current exposure to NOACs compared with current exposure to VKAs.

MAIN OUTCOME MEASURES

HRs of ischaemic stroke and systemic embolism (SE), major bleeding, gastrointestinal (GI) bleeding, intracranial bleeding, myocardial infarction and all-cause mortality.

RESULTS

In as-treated analyses, the rates of ischaemic stroke/SE were similar between NOACs and VKAs (HR 0.94; 95% CI 0.62 to 1.42), as were the rates of major bleeding (HR 0.86; 95% CI 0.56 to 1.33). NOACs also significantly increased the risk of GI bleeding (HR 1.78; 95% CI 1.27 to 2.48). In patients with NVAF and CKD, NOACs and VKAs remained comparable with respect to the risk of ischaemic stroke/SE (HR 0.79; 95% CI 0.40 to 1.58) and major bleeding (HR 0.88; 95% CI 0.47 to 1.62), with no difference in the risk of GI bleeding (HR 0.99; 95% CI 0.63 to 1.55). Similar results were obtained in on-treatment analyses using a time-dependent exposure definition.

CONCLUSIONS

Our results suggest that in the UK primary care, NOACs are overall effective and safe alternatives to VKAs, among patients with NVAF altogether, as well as in patients with NVAF and CKD.

Drug Class, Renal Elimination, and Outcomes of Direct Oral Anticoagulants in Asian Patients: A Meta-Analysis

BACKGROUND

Direct oral anticoagulants (DOACs) have a better risk benefit profile in Asian patients with atrial fibrillation (AF). Whether treatment effects could be modified by drug class and dependency on renal elimination of studied agents has not yet been explored.

METHODS

We searched PubMed, CENTRAL, and CINAHL databases through November 2016 for phase III randomized controlled trials comparing DOACs with warfarin in patients with AF. Efficacy and safety outcomes were pooled according to drug class and dependency on renal elimination of DOACs and were compared with the Mantel-Haenszel fixed-effects model. Effect differences were assessed with Bucher's indirect comparisons using common estimates, once heterogeneity was low, and with the Bayesian method.

RESULTS

Among 6496 Asian patients from 6 trials, both direct thrombin inhibitors and factor Xa inhibitors, compared with warfarin, were associated with lower risks of stroke or systemic embolism and major bleeding (risk ratio [95% confidence interval], 0.51 [0.33-0.78], 0.74 ([0.58-0.96], 0.60 [0.41-0.86], and 0.59 [0.47-0.76], respectively). There was no between-group difference in direct thrombin inhibitors and factor Xa inhibitors or in DOACs with renal elimination less than 50% and 50% or greater (all I² < 25% and interaction P > .05). Indirect comparisons within strata of drug class and dependency on renal elimination showed no preferential effect of any given regimen over another. There was no difference in effects on ischemic and hemorrhagic stroke, intracranial hemorrhage, myocardial infarction, and all-cause mortality between DOACs stratified by pharmacologic characteristics.

CONCLUSIONS

DOACs, as a therapeutic class, outperform warfarin in efficacy and safety in Asian patients with AF.

Association Between Use of Non-Vitamin K Oral Anticoagulants With and Without Concurrent Medications and Risk of Major Bleeding in Nonvalvular Atrial Fibrillation

IMPORTANCE

Non-vitamin K oral anticoagulants (NOACs) are commonly prescribed with other medications that share metabolic pathways that may increase major bleeding risk.

OBJECTIVE

To assess the association between use of NOACs with and without concurrent medications and risk of major bleeding in patients with nonvalvular atrial fibrillation.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study using data from the Taiwan National Health Insurance database and including 91 330 patients with nonvalvular atrial fibrillation who received at least 1 NOAC prescription of dabigatran, rivaroxaban, or apixaban from January 1, 2012, through December 31, 2016, with final follow-up on December 31, 2016.

EXPOSURES

NOAC with or without concurrent use of atorvastatin; digoxin; verapamil; diltiazem; amiodarone; fluconazole; ketoconazole, itraconazole, voriconazole, or posaconazole; cyclosporine; erythromycin or clarithromycin; dronedarone; rifampin; or phenytoin.

MAIN OUTCOMES AND MEASURES

Major bleeding, defined as hospitalization or emergency department visit with a primary diagnosis of intracranial hemorrhage or gastrointestinal, urogenital, or other bleeding. Adjusted incidence rate differences between person-quarters (exposure time for each person during each quarter of the calendar year) of NOAC with or without concurrent medications were estimated using Poisson regression and inverse probability of treatment weighting using the propensity score.

RESULTS

Among 91 330 patients with nonvalvular atrial fibrillation (mean age, 74.7 years [SD, 10.8]; men, 55.8%; NOAC exposure: dabigatran, 45 347 patients; rivaroxaban, 54 006 patients; and apixaban, 12 886 patients), 4770 major bleeding events occurred during 447 037 person-quarters with NOAC prescriptions. The most common medications co-prescribed with NOACs over all person-quarters were atorvastatin (27.6%), diltiazem (22.7%), digoxin (22.5%), and amiodarone (21.1%). Concurrent use of amiodarone, fluconazole, rifampin, and phenytoin with NOACs had a significant increase in adjusted incidence rates per 1000 person-years of major bleeding than NOACs alone: 38.09 for NOAC use alone vs 52.04 for amiodarone (difference, 13.94 [99% CI, 9.76-18.13]); 102.77 for NOAC use alone vs 241.92 for fluconazole (difference, 138.46 [99% CI, 80.96-195.97]); 65.66 for NOAC use alone vs 103.14 for rifampin (difference, 36.90 [99% CI, 1.59-72.22); and 56.07 for NOAC use alone vs 108.52 for phenytoin (difference, 52.31 [99% CI, 32.18-72.44]; P < .01 for all comparisons). Compared with NOAC use alone, the adjusted incidence rate for major bleeding was significantly lower for concurrent use of atorvastatin, digoxin, and erythromycin or clarithromycin and was not significantly different for concurrent use of verapamil; diltiazem; cyclosporine; ketoconazole, itraconazole, voriconazole, or posaconazole; and dronedarone.

CONCLUSIONS AND RELEVANCE

Among patients taking NOACs for nonvalvular atrial fibrillation, concurrent use of amiodarone, fluconazole, rifampin, and phenytoin compared with the use of NOACs alone, was associated with increased risk of major bleeding. Physicians prescribing NOAC medications should consider the potential risks associated with concomitant use of other drugs.