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

Comparative Effectiveness and Safety of Off-Label Underdosed Direct Oral Anticoagulants in Asian Patients with Atrial Fibrillation: A Systematic Review and Meta-analysis

INTRODUCTION

Off-label underdosed direct oral anticoagulants (DOACs) are commonly utilised in Asian patients with atrial fibrillation (AF) since they are prone to bleeding with OACs. However, the efficacy and safety of off-label underdosing DOACs are controversial. This study aimed to compare the effectiveness and safety of off-label underdosed DOACs in Asian patients with AF.

METHODS

PubMed, Embase, Cochrane library, and ClinicalTrials.gov were searched from 2010 to July 5, 2024, for randomised controlled trials or observational studies that compared off-label DOACs and on-label/warfarin in Asian patients with AF. The primary outcomes included ischaemic stroke or systemic embolism (ISSE) and major bleeding (MB), while secondary outcomes included all-cause death, gastrointestinal bleeding (GIB), intracranial haemorrhage (ICH), and myocardial infarction (MI). Hazard ratios (HRs) with 95% confidence intervals (CIs) were pooled using random-effects models.

RESULTS

Twenty observational studies were included. Seventeen studies compared off-label underdosed DOACs versus on-label DOACs, whereas five studies compared off-label underdosed DOACs versus warfarin. Off-label underdosed DOACs were associated with higher risk of ISSE (pooled HR [pHR] = 1.17; 95% CI: 1.00-1.38, p = 0.048) and ICH (pHR = 1.27; 95% CI: 1.06-1.52, p = 0.010) versus on-label. Subgroup analysis demonstrated increased ISSE risk with off-label underdosed rivaroxaban compared to on-label (pHR = 1.49; 95% CI: 1.07-2.08). Compared to warfarin, off-label underdosed DOACs were associated with decreased risk of MB (pHR = 0.46; 95% CI: 0.32-0.65, p < 0.001), GIB (pHR = 0.52; 95% CI: 0.29-0.93, p = 0.028), ICH (pHR = 0.60; 95% CI: 0.42-0.86, p = 0.005), and all-cause death (pHR = 0.70; 95% CI: 0.56-0.87, p = 0.001), while illustrating similar ISSE risk.

CONCLUSIONS

Off-label underdosed DOACs, particularly rivaroxaban, was associated with increased ISSE risk but did not decrease bleeding compared to on-label. Adherence to appropriate DOAC doses should be emphasised to achieve the best clinical outcomes for Asian patients with AF.

Comparison of different direct oral anticoagulant regimens in atrial fibrillation patients with high bleeding risk

BACKGROUND

The optimal dose of direct oral anticoagulants (DOACs) to prevent ischemic stroke (IS) and systemic thromboembolism (STE) in atrial fibrillation (AF) patients with a predisposing bleeding risk remains unclear.

OBJECTIVE

The purpose of this study was to compare the effectiveness and safety of different DOAC dosage regimens in AF patients with high bleeding risk but low thrombosis risk.

METHODS

This retrospective observational study was conducted with the National Health Insurance claims database in Taiwan to include AF patients aged 20 up to 75 years, under DOAC therapy, with CHA2DS2-VASc score of 1 for males and 2 for females and HAS-BLED score ≥3. Standard-dose regimen was defined as dabigatran 300 mg, rivaroxaban 20 mg, apixaban 10 mg, or edoxaban 60 mg per day. Any other lower-dose regimen were defined as the low-dose regimen. The primary outcomes were IS and major bleeding (MB). The secondary outcomes were STE, gastrointestinal bleeding, intracranial hemorrhage, and cardiovascular death.

RESULTS

A total of 964 patients were included (52.1% standard-dose regimen). Median HAS-BLED score was 3 [interquartile range 3-3]. Compared with standard-dose group, patients in the low-dose group had a significantly increased risk of IS (adjusted hazard ratio [aHR] 5.13; 95% confidence interval 1.37-19.22) and STE (aHR 3.14 [1.05-9.37]) but similar risk of MB (aHR 0.45 [0.12-1.67]). The risks of other hemorrhage and cardiovascular death were similar between the 2 dose groups.

CONCLUSION

Among patients with a predominant bleeding risk but relatively low thrombosis risk, the low-dose DOAC regimen is not a more appropriate selection than standard-dose regimen.

A cross-sectional study of appropriateness evaluation of anticoagulation therapy for inpatients with nonvalvular atrial fibrillation

Background: Oral anticoagulants (OACs) are essential for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF). However, the appropriateness of anticoagulation treatment in locally practice remains unclear. This study evaluated compliance with anticoagulation therapy concerning the guidelines and drug labels in patients with NVAF. Methods: Hospitalized patients diagnosed with NVAF between 1 November 2020, and 31 December 2021, were retrospectively enrolled. The appropriateness of anticoagulation regimens at discharge was evaluated based on a flowchart designed according to atrial fibrillation (AF) guidelines and medication labels. Furthermore, we explored factors potentially influencing the "no-use of OACs" using binary logistic regression and verified anticoagulation-related issues through a physician questionnaire. Results: A total of 536 patients were enrolled in this study, including 254 patients (47.4%) with inappropriate anticoagulation regimens. 112 patients (20.9%) were categorized as "underdosing-use of OACs," 134 (25%) who needed anticoagulation therapy were "no-use of OACs" and eight (1.5%) were "over-use of OACs." The results of a binary logistic regression analysis showed that paroxysmal AF (odds ratio [OR], 7.74; 95% confidence interval [CI], 4.57-13.10), increased blood creatinine levels (OR, 1.88; 95% CI, 1.11-3.16), hospitalized pacemaker implantation (OR, 6.76; 95% CI, 2.67-17.11), percutaneous coronary intervention (OR, 3.35; 95% CI, 1.44-7.80), and an increased HAS-BLED score (OR, 1.62; 95% CI, 1.11-2.35) were associated with "no-use of OACs" in patients with NVAF who had indications for anticoagulation therapy. Conclusion: For patients with NVAF with severe renal dysfunction and paroxysmal AF, anticoagulation therapy was inadequate. The underdosing-use of OACs in patients with NVAF was frequently observed. We recommend an anticoagulation management team to tailor anticoagulation regimens to suit each patient's needs.

Effectiveness and safety of reduced-dose rivaroxaban for elderly patients with non-valvular atrial fibrillation: A subanalysis of the EXPAND study

BACKGROUND

Establishing the appropriate rivaroxaban dose in older patients with non-valvular atrial fibrillation (NVAF) is important because of the high risk of adverse events. In this EXPAND study subanalysis, we examined the safety and efficacy of standard-dose (15 mg/day) and non-recommended reduced-dose (10 mg/day) rivaroxaban in patients aged ≥65 years with NVAF and preserved renal function.

METHODS

The entire analysis population (ALL cohort [n = 3982]; ≥65 years) was divided into early elderly (ELD) (65-74 years [n = 1444]) and late ELD (≥75 years [n = 2386]) sub-cohorts. Each sub-cohort was divided into reduced-dose and standard-dose groups. Kaplan-Meier survival curves with adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) were used to assess efficacy (thromboembolic events) and safety (hemorrhagic events) outcomes.

RESULTS

The aHR for major bleeding did not differ between the dosages in any of the cohorts (aHRs: 0.86-0.93). There were no significant differences in the occurrence of stroke + systemic embolism (SE) or stroke + SE + myocardial infarction (MI) + cardiovascular (CV) death among the cohorts. The aHR for MI/unstable angina + interventional/CV surgery + CV death was higher with 10-mg/day rivaroxaban than 15-mg/day rivaroxaban in the ALL cohort (aHR: 1.56 [95% CI 1.02-2.37], p = 0.039) and the late ELD sub-cohort (aHR: 1.86 [95% CI 1.01-3.42], p = 0.045).

CONCLUSIONS

Reduced-dose rivaroxaban may increase the risk of coronary artery events. The use of rivaroxaban 15 mg/day in patients with NVAF aged ≥75 years with preserved renal function was supported.

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.

Phenotype-directed clinically driven low-dose direct oral anticoagulant for atrial fibrillation

Clinically-driven dose reduction of direct oral anticoagulants in individuals with atrial fibrillation is prevalent worldwide. However, a paucity of evidence to tailor dose selection remained as clinical unmet need. Current doses of anticoagulant were determined largely by landmark clinical trials, in which the enrolled subjects were carefully selected and without major comorbidities. Our study reviewed the relevant real-world studies in specific patient phenotypes, including renal and hepatic diseases, elderly, low body weight, Asians and presence of concomitant drug-drug interactions. Thorough investigations toward the efficacy and safety of direct oral anticoagulants in reduced doses will facilitate substituting current universal approach with individualized prescriptions.

Oral anticoagulants and concurrent rifampin administration in tuberculosis patients with non-valvular atrial fibrillation

BACKGROUND

Evidence and guidelines for Non-vitamin K antagonist oral anticoagulants (NOACs) use when prescribing concurrent rifampin for tuberculosis treatment in patients with non-valvular atrial fibrillation (NVAF) are limited.

METHODS

Using the Korean National Health Insurance Service database from January 2009 to December 2018, we performed a population-based retrospective cohort study to assess the net adverse clinical events (NACE), a composite of ischemic stroke or systemic embolism and major bleeding, of NOACs compared with warfarin among NVAF patients taking concurrent rifampin administration for tuberculosis treatment. After a propensity matching score (PSM) analysis, Cox proportional hazards regression was performed in matched cohorts to investigate the clinical outcomes.

RESULTS

Of the 735 consecutive patients selected, 465 (63.3%) received warfarin and 270 (36.7%) received NOACs. Among 254 pairs of patients after PSM, the crude incidence rate of NACE was 25.6 in NOAC group and 32.8 per 100 person-years in warfarin group. There was no significant difference between NOAC and warfarin use in NACE (hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.48-1.14; P = 0.172). Major bleeding was the main driver of NACE, and NOAC use was associated with a statistically significantly lower risk of major bleeding than that with warfarin use (HR, 0.63; 95% CI, 0.40-1.00; P = 0.0499).

CONCLUSIONS

In our population-based study, there was no statically significant difference in the occurrence of NACE between NOAC and warfarin use. NOAC use may be associated with a lower risk of major bleeding than that with warfarin use.

Safety of recanalization therapy in patients with acute ischemic stroke on direct oral anticoagulants: A sub-analysis of PASTA registry study

BACKGROUND

The safety of intravenous recombinant tissue plasminogen activator (rtPA) and mechanical thrombectomy (MT) in patients treated with direct oral anticoagulants (DOACs) before stroke has not been fully investigated. Therefore, we aimed to investigate the safety of recanalization therapy in patients receiving DOACs.

METHODS

We assessed data from a prospective multicenter registry of patients with stroke, including those with acute ischemic stroke (AIS) treated with rtPA and/or MT who were administered DOACs. We evaluated the safety of recanalization considering the DOACs dosage and interval between the last DOAC intake and recanalization.

RESULTS

The final analysis included 108 patients (women, n = 54; median age, 81 years; DOAC overdose, n = 7; appropriate dose, n = 74; and inappropriate low dose, n = 27). The rate of any ICH differed significantly among overdose-, appropriate dose-, and inappropriate-low dose DOACs groups (71.4, 23.0, and 33.3%, respectively; P = 0.0121), whereas no significant difference was observed in respect of symptomatic ICH (P = 0.6895). Multivariate analysis showed that the National Institutes of Health Stroke Scale score on admission (odds ratio [OR]: 1.06, 95% confidence interval [CI]: 1.01-1.11; P = 0.0267) and overdose-DOAC (OR: 8.40, 95% CI: 1.24-56.88; P = 0.0291) were independently associated with any ICH. No relationship was observed between the timing of the last DOAC intake and occurrence of ICH in patients treated with rtPA and/or MT (all P > 0.05).

CONCLUSION

Recanalization therapy during DOAC treatment may be safe in selected patients with AIS, if it is performed >4 h after the last DOAC intake and the patient is not overdosed with DOACs.

REGISTRATION

https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000034958.

Direct Oral Anticoagulants: Laboratory Challenges and Antidotes

The use of direct oral anticoagulants (DOACs) is increasing in patients needing treatment of venous thromboembolism (VTE) and stroke prevention in atrial fibrillation (SPAF). This is due to the net clinical benefit in comparison to vitamin K antagonists (VKAs). The rise in DOAC use is accompanied by a remarkable reduction in heparin and VKA prescriptions. However, this rapid change in anticoagulation patterns brought new challenges to patients, prescribers, laboratories, and emergency physicians. Patients have new liberties concerning nutritional habits and comedication and no longer need frequent monitoring or dose adjustments. Still, they have to comprehend that DOACs are potent anticoagulants that may cause or contribute to bleeding. Challenges for the prescriber include decision pathways for choosing the right anticoagulant and dosage for a specific patient and to change bridging practice in case of invasive procedures. Laboratory personnel are challenged by DOAC due to limited 24/7 availability of specific DOAC quantification tests and by the impact of DOAC on routine coagulation assays and thrombophilia tests. Challenges for the emergency physician result from the increasing age of DOAC anticoagulated patients, the difficulties to establish last intake of DOAC type and dosage, to interpret coagulation test results in emergency situations, and to make decisions for or against DOAC reversal strategies in acute bleeding or urgent surgery. In conclusion, although DOACs make long-term anticoagulation safer and more convenient for patients, DOACs pose challenge to all healthcare providers involved in anticoagulation decisions. The key to correct patient management and optimal outcome therefore lies in education.

Outcomes of On-Label Reduced-Dose Edoxaban in Patients With Atrial Fibrillation: The LEDIOS Registry

BACKGROUND

Non-vitamin K antagonist oral anticoagulants (NOACs) are effective in preventing thromboembolisms and reduce the risk of bleeding compared with warfarin. There are few reports on the outcomes of on-label reduced-dose NOACs. The aim of this study was to assess the safety and efficacy of on-label reduced-dose edoxaban in patients with atrial fibrillation (AF).

METHODS

This study is a multi-center, prospective, non-interventional study to evaluate the safety and efficacy of on-label reduced-dose edoxaban in patients with AF. We evaluated outcomes of major bleeding, stroke or systemic embolism, all-cause death, and composite clinical outcomes.

RESULTS

A total of 2,448 patients (mean age 75.0 ± 8.3 years, 801 [32.7%] males) was included in the present study. The mean CHA₂DS₂-VASc score was 3.7 ± 1.5. Major bleeding events occurred at a rate of 1.34%/yr. The event rate of strokes and systemic embolisms was 1.13%/yr. The overall net clinical outcomes occurred at a rate of 3.19%/yr. There were no significant differences according to the number of dose reduction criteria, renal dysfunction, or body weight. Higher HAS-BLED score and higher combination of CHA₂DS₂-VASc and HAS-BLED score was associated with an increased risk of composite clinical outcomes compared to the lower score groups.

CONCLUSIONS

This study was the largest prospective real-world study to investigate the safety and efficacy of on-label low-dose edoxaban in an Asian population. Reduced-dose edoxaban can be used safely in patients with severe renal dysfunction or extremely low body weight. Our observation suggests that physicians should consider bleeding risk even in a low-dose regimen.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03554837.

Prevalence and risk of inappropriate dosing of direct oral anticoagulants in two Swiss atrial fibrillation registries

BACKGROUND

Direct oral anticoagulants (DOACs) have a favourable risk-benefit profile compared to vitamin K-antagonists (VKAs) in atrial fibrillation (AF). Dosing is based on age, weight and renal function, without need of routine monitoring.

METHODS AND RESULTS

In two prospective, multicentre AF cohorts (Swiss-AF, BEAT-AF) patients were stratified as receiving VKAs or adequately-, under- or overdosed DOACs, according to label. Primary outcome was a composite of major adverse clinical events (MACE), defined as cardiovascular death, myocardial infarction (MI), ischaemic stroke and systemic embolism. Secondary outcomes included major bleeding. Adjustment for confounding was performed. Median follow-up was 4 years. Of 3236 patients, 1875 (58%) were on VKAs and 1361 (42%) were on DOACs, of which 1137 (83%) were adequately-, 134 (10%) over- and 90 (7%) under-dosed. Compared to adequately dosed individuals, overdosed patients were more likely to be older and female. Underdosing correlated with concomitant aspirin therapy and coronary artery disease. Both groups had higher CHA₂DS₂-VASc scores. Patients on overdosed DOACs had higher incidence of MACE (HR 1.75; CI 1.10-2.79; adjusted-HR: 1.22) and major bleeding (HR 1.99; CI 1.14-3.48; adjusted-HR: 1.51). Underdosing was not associated with a higher incidence of MACE (HR 0.94; CI 0.46-1.92; adjusted-HR 0.61) or major bleeding (HR 1.07; CI 0.46-2.46; adjusted-HR 0.82). After adjustment, all CIs crossed 1.0.

CONCLUSION

Inappropriate DOAC-dosing was more prevalent in multimorbid patients, but did not correlate with higher risks of adverse events after adjusting for confounders. DOAC prescription should follow label.

Racial and ethnic differences in pharmacotherapy to prevent coronary artery disease and thrombotic events

Awareness of racial/ethnic disparities represents a key challenge for healthcare systems that attempt to provide effective healthcare and to reduce existing inequalities in the use of and adherence to guideline-recommended cardiovascular drugs to improve clinical outcomes for cardiovascular disease (CVD). In this review, we describe important racial/ethnic differences between and within ethnic groups in the prevalence, risk factors, haemostatic factors, anti-inflammatory and endothelial markers, recurrence, and outcomes of CVD.

We discuss important differences in the selection, doses, and response [efficacy and adverse drug reactions (ADRs)] in ethnically diverse patients treated with antithrombotics or lipid-lowering drugs. Differences in drug response are mainly related to racial/ethnic differences in the frequency of polymorphisms in genes encoding drug-metabolizing enzymes (DMEs) and drug transporters. These polymorphisms markedly influence the pharmacokinetics, dose requirements, and safety of warfarin, clopidogrel, and statins. This review aims to support a better understanding of the genetic differences between and among populations to identify patients who may experience an ADR or a lack of drug response, thus optimizing therapy and improving outcomes. The greater the understanding of the differences in the genetic variants of DMEs and transporters that determine the differences in the exposure, efficacy, and safety of cardiovascular drugs between races/ethnicities, the greater the probability that personalized medicine will become a reality.

Rivaroxaban Underdose for Atrial Fibrillation with Stable Coronary Disease: The AFIRE Trial Findings

Background  Rivaroxaban monotherapy was noninferior to combination therapy (rivaroxaban plus antiplatelet therapy) in efficacy but superior in safety in the Atrial Fibrillation and Ischemic Events with Rivaroxaban in Patients with Stable Coronary Artery Disease (AFIRE) trial. Among 2,215 patients with atrial fibrillation (AF) and stable coronary artery disease (CAD), 1,378 had baseline creatinine clearance (CrCl) ≥50 mL/min and received 10 (underdose) or 15 mg/d (standard-dose) rivaroxaban. We aimed to assess the effects of rivaroxaban underdose on clinical outcomes.

Methods  We assessed efficacy endpoint (a composite of stroke, systemic embolism, myocardial infarction, unstable angina requiring revascularization, and death from any cause) and major bleeding in the subgroup of patients with preserved renal function in the AFIRE trial.

Results  Age ≥75 years, female sex, lower CrCl, heart failure, and percutaneous coronary intervention history were associated with the underdose prescription. The underdose group had a similar incidence of the efficacy endpoint (3.62 vs. 3.51% per patient-year; p  = 0.871) and significantly lower incidence of major bleeding (0.82 vs. 2.17% per patient-year; p  = 0.022) than the standard-dose group. In patients receiving monotherapy, the incidences of efficacy endpoint and major bleeding were similar between the groups, whereas in those receiving combination therapy, the incidence of major bleeding was significantly lower in the underdose group than that in the standard-dose group.

Conclusion  In patients with AF, stable CAD, and preserved renal function, rivaroxaban underdose was associated with similar rates of thrombotic events but a lower incidence of hemorrhagic events than the standard dose.

Clinical Trial Registration  AFIRE UMIN Clinical Trials Registry ( https://www.umin.ac.jp/ctr/ ), number UMIN000016612, and ClinicalTrials.gov, number NCT02642419.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

TRIAL REGISTRATION

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

Vitamin-K-antagonist phenprocoumon versus low-dose direct oral anticoagulants (DOACs) in patients with atrial fibrillation: a real-world analysis of German claims data

Background

For stroke prevention in patients with atrial fibrillation (AF), direct oral anticoagulants (DOACs) have been increasingly prescribed instead of vitamin-K-antagonists (VKA). For some patients a lower dosage of DOACs (ld-DOACs) is recommended. Ld-DOAC prescribing seems to be common, although previous studies did not show clear superiority of ld-DOACs over warfarin. In Germany, phenprocoumon is used almost exclusively as VKA. Randomized controlled trials comparing DOACs and phenprocoumon in the general population of patients with AF do not exist. Therefore, we aimed to compare ld-DOACs and phenprocoumon in a real-world setting in Germany.

Methods

In a retrospective observational cohort study, claims data from a group of small to medium-sized health insurance companies were analysed. Risks for the outcomes thromboembolism, death and major bleeding were estimated by Cox regression. Out of 93,685 patients with atrial fibrillation and a first prescription of an oral anticoagulant, 20,179 receiving VKA and 21,724 ld-DOACs (29.6% of all DOAC patients) were included. For the sensitivity analysis phenprocoumon was compared to the five ld-DOAC groups (ld-apixaban, ld-dabigatran, ld-edoxaban, ld-rivaroxaban, and the composite of all ld-DOACs) after propensity-score matching.

Results

Phenprocoumon was associated with statistically significant fewer thromboembolic events (HR = 1.29, 95% CI [1.13, 1.48], p < .001) and deaths (HR = 1.52, 95% CI [1.41, 1.63], p < .001) and a non-significant higher bleeding risk (HR = 0.89, 95% CI [0.79, 1.00], p = .051) than composite ld-DOAC. Regarding the subgroups, only patients with ld-apixaban had a statistically significant higher risk for thromboembolic events (HR = 1.42, 95% CI [1.21, 1.65], p < .001) and a lower bleeding risk (HR = 0.75, 95% CI [0.65, 0.86], p < .001). Ld-apixaban, ld-edoxaban, and ld-rivaroxaban were associated with a higher risk of death. The sensitivity analysis confirmed these associations.

Conclusion

Phenprocoumon seems to be superior to ld-DOACs for patients with AF. As a hypothesis phenprocoumon might turn out to be the wiser choice for high-risk patients with AF as compared to ld-DOACs, especially regarding thromboembolic events and death. Therefore, RCTs comparing ld-DOACs with phenprocoumon are needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-022-00389-9.

Effectiveness and Safety of Reduced and Standard Daily Doses of Direct Oral Anticoagulants in Patients with Nonvalvular Atrial Fibrillation: A Cohort Study Using National Database Representing the Japanese Population

Purpose

To compare the effectiveness and safety of reduced or standard daily doses of direct oral anticoagulants (DOACs) with warfarin in Japanese patients with nonvalvular atrial fibrillation (NVAF). We used post-hoc analyses to identify patient groups that could benefit from reduced-dose DOACs.

Patients and Methods

Using the National Database of Health Insurance Claims and Specific Health Checkups of Japan, we identified 944,776 patients with NVAF who had started an oral anticoagulant after at least one year of non-use between April 2011 and March 2016. We matched patients taking any, reduced, or standard doses of DOACs 1:1 with those taking warfarin. We measured treatment effectiveness based on admission due to stroke or systemic embolism (S/SE) and safety based on admission due to any bleeding (defined as major bleeding, MB). We compared both outcomes between DOACs and warfarin using the Cox proportional hazards model. We used post-hoc analysis to match patients receiving reduced-dose DOACs to those receiving standard-dose DOACs and compared treatment effectiveness and safety.

Results

More than half of patients receiving DOACs used a reduced dose. The occurrences of S/SE and MB in patients receiving any, reduced, or standard doses of DOACs were equal to or lower than those receiving warfarin. In the post-hoc analysis, the risk of S/SE and MB was similar between reduced and standard doses of DOACs except for those with a history of cerebral infarction and CHA2DS2-VASc score ≥3, where the risk of S/SE was lower for reduced doses of any and individual DOACs.

Conclusion

Findings from the current study are consistent with recent Asian and global studies but different from most studies conducted in North America and Europe, where patients receiving a reduced dose of DOACs had an increased risk of S/SE. Future studies should test the reproducibility of results from the current study.

Efficacy and Safety of Clinically Driven Low-Dose Treatment with Direct Oral Anticoagulants in Asians with Atrial Fibrillation: a Systematic Review and Meta-analysis

PURPOSE

Although clinically driven low-dose (CDLD) treatment with direct oral anticoagulants (DOACs) is frequently administered to Asian patients with atrial fibrillation, clinical evidence confirming its efficacy remains insufficient. We evaluated the clinical efficacy and safety of CDLD treatment with DOACs compared to on-label dose treatment in Asian patients with atrial fibrillation and assessed the differences in the baseline characteristics between patients receiving these treatments.

METHODS

We searched the MEDLINE, CENTRAL, EMBASE, Web of Science, and Scopus databases for articles from inception through July 2020.

RESULTS

Thirteen studies were included in this meta-analysis. The baseline characteristics of the CDLD group were significantly different from those of the standard dose (STD) and standard low-dose (SLD) groups. The incidences of thromboembolic events (risk ratio [RR] 0.46, 95% confidence interval [CI] 0.29-0.73, p < 0.001) and major bleeding (RR 0.55, 95% CI 0.35-0.87, p = 0.01) in the CDLD group were lower than those in the SLD group; however, they were comparable with those in the STD group. The incidence of a composite endpoint in the CDLD group was not significantly different from that in the STD group but was significantly lower than that in the SLD group (RR 0.50, 95% CI 0.38-0.65, p < 0.001).

CONCLUSION

The clinical outcomes of CDLD treatment showed no difference compared to those of the STD treatment despite the vulnerable baseline characteristics of the CDLD group for thromboembolic and major bleeding events.

Non-Vitamin K Oral Anticoagulants Assessment in High Risk of Bleeding Patients with Non-Valvular Atrial Fibrillation

Atrial fibrillation (AF) is commonly associated with advanced age and the presence of multiple, concomitant acute and chronic health conditions, placing this population at high risk for serious therapeutic side effects. Nonvitamin K antagonist oral anticoagulants (NOACs) are increasingly used for stroke prevention in patients with atrial fibrillation. The purpose of this study was to investigate the effectiveness and safety of NOAC in a group at high risk of bleeding complications, in a real-world setting. We conducted a retrospective analysis of a high-risk cohort of 418 patients (pts) followed-up in our anticoagulation unit; data on patient characteristics, anticoagulation treatment, and bleeding and thrombotic complications were evaluated. The population had a median age of 77.8 ± 10.3 years and the mean CHA2DS2-VASc score was 3.85 (SD ± 1.4). Overall, 289 (69.1%) were ≥75 years old. During a mean follow-up time of 51.2 ± 35.7 months, we observed a rate of any bleeding of 7, a clinically relevant non-major bleeding rate of 4.8, a major bleeding rate of 2.2, a stroke rate of 1.6, and a rate of thrombotic events of 0.28 per 100 patient-years. There were 59 hospitalizations due to any cause (14.1%) and 36 (8.6%) deaths (one due to ischemic stroke). A structured follow-up, with judicious prescribing and drug compliance, may contribute to preventing potential complications.

Comparing Warfarin and 4 Direct Oral Anticoagulants for the Risk of Dementia in Patients With Atrial Fibrillation

Background and Purpose

Atrial fibrillation is a risk factor for dementia, and oral anticoagulant use is associated with a decreased risk of dementia in patients with atrial fibrillation. We aimed to investigate whether the risk of dementia would be different between patients treated with direct oral anticoagulants (DOACs) compared with those with warfarin.

Methods

Using the Korean nationwide claims database from January 2014 to December 2017, we identified oral anticoagulant–naive nonvalvular atrial fibrillation patients aged ≥40 years. For the comparisons, warfarin and DOAC groups were balanced using the inverse probability of treatment weighting method. The primary outcome was incident dementia.

Results

Among 72 846 of total study patients, 25 948 were treated with warfarin, and 46 898 were treated with DOAC (17 193 with rivaroxaban, 9882 with dabigatran, 11 992 with apixaban, and 7831 with edoxaban). During mean 1.3±1.1 years of follow-up, crude incidence of dementia was 4.87 per 100 person-years (1.20 per 100 person-years for vascular dementia and 3.30 per 100 person-years for Alzheimer dementia). Compared with warfarin, DOAC showed a comparable risks of dementia, vascular dementia, and Alzheimer dementia. In subgroup analyses, DOAC was associated with a lower risk of dementia than warfarin, particularly in patients aged 65 to 74 years (hazard ratio, 0.815 [95% CI, 0.709–0.936]) and in patients with prior stroke (hazard ratio, 0.891 [95% CI, 0.820–0.968]). When comparing individual DOACs with warfarin, edoxaban was associated with a lower risk of dementia (hazard ratio, 0.830 [95% CI, 0.740–0.931]).

Conclusions

In this large Asian population with atrial fibrillation, DOAC showed a comparable risk of dementia with warfarin overall. DOACs appeared more beneficial than warfarin, in those aged 65 to 74 years or with a history of stroke. For specific DOACs, only edoxaban was associated with a lower risk of dementia than warfarin.

The Importance of Appropriate Dosing of Nonvitamin K Antagonist Oral Anticoagulants for Stroke Prevention in Patients with Atrial Fibrillation

Preventing thromboembolic events, while minimizing bleeding risks, remains challenging when managing patients with atrial fibrillation (AF). Several factors contribute to current dosing patterns of nonvitamin K antagonist oral anticoagulants (NOACs), including patient characteristics, comorbidities, and physician judgment. Application of NOAC doses inconsistent with the drug labels may cause patients to receive either subtherapeutic (increasing stroke risk) or supratherapeutic (increasing bleeding risk) anticoagulant levels. In clinical practice, under- or over-dosing of NOACs in patients with AF is not uncommon. This analysis of prospective and retrospective registry and database studies on NOAC use in patients with AF (with at least 250 patients in each treatment arm) showed that under-dosing may be associated with reduced effectiveness for stroke prevention, with similar or even increased bleeding than with the standard dose. This may reflect underlying conditions and patient factors that increase bleeding despite NOAC dose reduction. Such factors could drive the observed overuse of reduced NOAC dosages, often making the prescription of reduced-dose NOAC an intentional label deviation. In contrast, over-dosing more likely occurs accidentally; instead of providing benefits, it may be associated with worse safety outcomes than the standard dose, including increased bleeding risk and higher all-cause mortality rates. This review summarizes the main findings on NOAC doses usually prescribed to patients with AF in clinical practice.

Risk of major bleeding and thromboembolism in Asian patients with nonvalvular atrial fibrillation using direct oral anticoagulants versus warfarin

Background Bleeding and thromboembolism prevention is important in patients with nonvalvular atrial fibrillation receiving anticoagulants, including direct oral anticoagulants and warfarin. Asians have higher risks of bleeding complications when taking anticoagulants. However, evidence that considers laboratory parameters is lacking. Objective We aimed to compare the safety and effectiveness between direct oral anticoagulants and warfarin in Asian patients with nonvalvular atrial fibrillation. Setting Retrospective design using hospital-based data. Method This propensity score-matched cohort study included data extracted from the electronic medical records of the En Chu Kong Hospital Research Database. Main outcome measure Outcome measures were major bleeding and thromboembolism. Cox proportional hazard models were applied for evaluating hazard ratios with 95% confidence intervals. Results Among 1075 patients with nonvalvular atrial fibrillation, 687 and 388 were administered direct oral anticoagulants and warfarin, respectively. After propensity score matching, 264 patient pairs were selected. Compared with warfarin use, direct oral anticoagulant use was associated with similar risks for major bleeding and thromboembolism; however, the latter was associated with increased gastrointestinal bleeding risks (adjusted hazard ratio 3.59; 95% confidence interval, 1.31-11.39). Notably, an approximately 10 fold increased risk of gastrointestinal bleeding was observed in 0-6 month direct oral anticoagulant users (adjusted hazard ratio 10.13, 95% confidence interval 1.27-80.89). Conclusion Direct oral anticoagulant use was not associated with major bleeding and thromboembolism occurrence in Asian patients with nonvalvular atrial fibrillation. However, direct oral anticoagulant use was associated with increased gastrointestinal bleeding risks, especially when used within 0-6 months of direct oral anticoagulant use.

Impact of Weight on Clinical Outcomes of Edoxaban Therapy in Atrial Fibrillation Patients Included in the ETNA-AF-Europe Registry

BACKGROUND

Extremes of body weight may alter exposure to non-vitamin K antagonist oral anticoagulants and thereby impact clinical outcomes. This ETNA-AF-Europe sub-analysis assessed 1-year outcomes in routine care patients with atrial fibrillation across a range of body weight groups treated with edoxaban.

METHODS

ETNA-AF-Europe is a multinational, multicentre, observational study conducted in 825 sites in 10 European countries. Overall, 1310, 5565, 4346 and 1446 enrolled patients were categorised into ≤60 kg, >60-≤80 kg (reference weight group), >80-≤100 kg and >100 kg groups.

RESULTS

Patients weighing ≤60 kg were older, more frail and had a higher CHA2DS2-VASc score vs. the other weight groups. The rates of stroke/systemic embolism, major bleeding and ICH were low at 1 year (0.82, 1.05 and 0.24%/year), with no significant differences among weight groups. The annualised event rates of all-cause death were 3.50%/year in the overall population. After adjustment for eGFR and CHA2DS2-VASc score, the risk of all-cause death was significantly higher in extreme weight groups vs. the reference group.

CONCLUSIONS

Low rates of stroke and bleeding were reported with edoxaban, independent of weight. The risk of all-cause death was higher in extremes of weight vs. the reference group after adjustment for important risk modifiers, thus no obesity paradox was observed.

Direct Oral Anticoagulants in Asian Patients with Atrial Fibrillation: Consensus Recommendations by the Asian Pacific Society of Cardiology on Strategies for Thrombotic and Bleeding Risk Management

The disease burden of AF is greater in Asia-Pacific than other areas of the world. Direct oral anticoagulants (DOACs) have emerged as effective alternatives to vitamin K antagonists (VKA) for preventing thromboembolic events in patients with AF. The Asian Pacific Society of Cardiology developed this consensus statement to guide physicians in the management of AF in Asian populations. Statements were developed by an expert consensus panel who reviewed the available data from patients in Asia-Pacific. Consensus statements were developed then put to an online vote. The resulting 17 statements provide guidance on the assessment of stroke risk of AF patients in the region, the appropriate use of DOACs in these patients, as well as the concomitant use of DOACs and antiplatelets, and the transition to DOACs from VKAs and vice versa. The periprocedural management of patients on DOAC therapy and the management of patients with bleeding while on DOACs are also discussed.

Anticoagulation in Very Old Patients with Atrial Fibrillation (AVOPA): A Descriptive Observational Study

BACKGROUND

In older patients with nonvalvular atrial fibrillation, oral anticoagulation is challenging, especially among very old patients. Even though positive effects of oral anticoagulation have been described in this age group (> 85 years), there is still a high rate of inappropriate dosing.

OBJECTIVE

This study examines the quality of care for very old hospitalized patients. The aims of this study were to (1) describe the percentage of patients receiving oral anticoagulation at discharge, (2) describe the quality of drug management at discharge, regarding dosing and contraindications, and (3) provide additional data towards establishing a benchmark for the quality of care in very old patients with atrial fibrillation.

METHODS

This study is a single-center descriptive observational study. The data from 407 patients aged > 85 years who were hospitalized in 2018 with nonvalvular atrial fibrillation were collected retrospectively from the patient charts. The assessment included specific geriatric aspects, such as falls, the Charlson Comorbidity Index, and nursing categorization.

RESULTS

During hospitalization, the proportion of anticoagulated patients increased from 57.5% (n = 234) to 67.3% (n = 274). We found an increasing trend in the use of direct oral anticoagulants, with an increase from 39.8% (n = 162) to 46.2% (n = 188). Regarding the quality of drug management, 13.8% (n = 56) of the patients were not anticoagulated even in the absence of a recognizable contraindication, whereas a contraindication was ignored in only 0.8% (n = 2 out of 188). Dosing was appropriate among all patients taking rivaroxaban, edoxaban, and dabigatran. The dose of apixaban was not reduced in 23.6% (n = 21 out of 89), although this dose reduction was necessary according to the dose adjustment criteria. An underdose of a direct oral anticoagulant was found in 26.1% of the patients (n = 49 out of 188).

CONCLUSIONS

Compared to the results reported in the literature, the percentage of very old patients with atrial fibrillation receiving anticoagulants was high. During hospitalization, the proportion of patients receiving a direct oral anticoagulant increased, which was in contrast to the trend in the proportion of patients taking phenprocoumon. Our results could help to find a benchmark for anticoagulation management among hospitalized very old patients.

Optimal Management of Anticoagulation Therapy in Asian Patients With Atrial Fibrillation

Stroke prevention is the cornerstone of management of atrial fibrillation (AF), and non-vitamin K antagonist oral anticoagulants (NOACs) are commonly prescribed. Because routine monitoring of anticoagulant effects of NOACs is not necessary, appropriate dosing following the criteria of each NOACs defined in pivotal randomized trials is important. Real-world data demonstrate that underdosing NOACs is associated with a higher risk of ischemic stroke without a lower risk of major bleeding. Furthermore, renal function of AF patients should be assessed using the Cockcroft-Gault formula to prevent overestimation that could result in overdosing of NOACs. The assessment of bleeding risk is important, and the HAS-BLED score should be used to help identify patients at high risk of bleeding (HAS-BLED score ≥3). Moreover, the HAS-BLED score should be reassessed at periodic intervals to address potentially modifiable bleeding risk factors because bleeding risks of AF patients are not static. When managing NOAC-related bleeding episodes, the possibility of occult malignancies (e.g., grastrointestinal [GI] tract cancers for patients experiencing GI bleeding and bladder cancer for patients with hematuria) should be kept in mind. Addressing all of these issues is crucial to achieving better clinical outcomes for anticoagulated AF patients. More efforts are necessary to incorporate clear and easy-to-follow recommendations about optimal management of anticoagulation into the guidelines to improve AF patient care.

Real-World Prevalence of Direct Oral Anticoagulant Off-Label Doses in Atrial Fibrillation: An Epidemiological Meta-Analysis

Background: The use of direct oral anticoagulant (DOAC) off-label doses in atrial fibrillation (AF) patients may result in poor clinical outcomes. However, the true prevalence remains scarce. This study aims at estimating the prevalence of DOAC off-label doses in AF patients.

Methods: Databases of MEDLINE, EMBASE, and COCHRANE were searched from inception through February 2020 for real-world studies that reported the off-label definition and prevalence data of AF patients using DOACs. The primacy outcomes were the overall prevalence of DOAC off-label doses and the corresponding underdose and overdose. The random-effects model was used for data synthesis. Variations on individual DOAC and different regions were examined by subgroup analyses.

Results: A total of 23 studies involving 162,474 AF patients were finally included. The overall prevalence of DOAC off-label doses was 24% (95% CI, 19–28%), with 18% for dabigatran, 27% for rivaroxaban, 24% for apixaban, and 26% for edoxaban. The prevalence of underdosed DOACs was 20% (95% CI, 16–24%) with significant difference among individual anticoagulants (13% for dabigatran, 22% for rivaroxaban, 22% for apixaban, and 18% for edoxaban; P_interaction=0.02). The prevalence of overdosed DOACs was 5% (95% CI, 3–7%), with the lowest prevalence observed in apixaban (2%). Subgroup analyses by regions demonstrated that the prevalence of DOAC off-label doses was higher in Asia (32%) than in North America (14%) and in Europe (22%), with underdose being predominant. Regardless of different regions, the prevalence of overdose was relatively low (4–6%).

Conclusion: This study provides an estimation of DOAC off-label doses in the real-world setting. The prevalence rate of DOAC off-label doses in AF patients was relatively high, with underdose being predominant. Clinicians in Asia preferred to prescribe underdose of DOACs to AF patients. More evidence about the appropriateness of DOAC off-label doses in AF patients is urgently needed. Education programs concerning the appropriate prescription of DOACs within the drug labels and accepted guidelines are necessary to DOAC prescribers to ensure the safety and effectiveness of anticoagulation therapy for patients with AF.

How cardiologists manage antithrombotic treatment of patients with atrial fibrillation undergoing percutaneous coronary stenting: the WOEST survey 2018

BACKGROUND

Antithrombotic treatment choices are complicated when patients have both atrial fibrillation (AF) and acute coronary syndrome and/or undergo percutaneous coronary intervention (PCI). In this study, we aimed to gain insight into antithrombotic management strategies in daily clinical practice.

METHODS

We invited interventional cardiologists to complete the WOEST (What is the Optimal antiplatElet & Anticoagulant Therapy in Patients With Oral Anticoagulation and Coronary StenTing) survey 2018. In this questionnaire, we presented a patient with a non-ST-elevation myocardial infarction (NSTEMI) and an elective PCI case.

RESULTS

The results were based on 118 completed questionnaires (response rate 69.4%). In the case of the AF patient with NSTEMI, most cardiologists indicated they would initiate dual antiplatelet therapy (acetylsalicylic acid and clopidogrel) and continue non-vitamin K antagonist oral anticoagulant (NOAC) therapy at admission and during coronary angiography/PCI. At discharge, 70.3% would prescribe triple antithrombotic therapy (oral anticoagulation, acetylsalicylic acid and clopidogrel), mostly for 1 month. One year after NSTEMI, 83.1% would cancel the antiplatelet therapy and prescribe NOAC monotherapy. For the AF patient undergoing elective PCI, 51.7% would start dual antiplatelet therapy prior to the procedure and 52.5% would discontinue NOAC therapy prior to the PCI. At discharge, 55.1% would start triple antithrombotic therapy. Furthermore, 25.4% responded they routinely prescribe a reduced dose of NOAC after discharge. One year after PCI, 89.0% would continue NOAC monotherapy.

CONCLUSION

The WOEST survey demonstrated heterogeneity in antithrombotic management strategies among interventional cardiologists. This observed variety mirrors the heterogeneity of the many guidelines and consensus documents. Further research is needed to guide patient-tailored medicine for AF patients undergoing PCI.

Direct Oral Anticoagulants in Atrial Fibrillation: Practical Considerations and Remaining Issues

Preventing thromboembolic events, while minimizing bleeding risks, remains challenging when managing patients with atrial fibrillation. Despite large and successful trial programs, several clinical concerns remain which commonly relate to fears of over- or underexposure to drugs and unfavorable outcomes. After a short summary of the main phase III trial findings, this short review discusses the evidence and clinical relevance of common clinical concerns (correct direct oral anticoagulant [DOAC] dosing; DOAC in moderate-to-severe renal impairment; and the relevance of fasting, nasogastric tube feeding, or high body mass index) on DOAC plasma levels. Finally, the need for specific DOAC antidotes will be addressed.

Off-label use of reduced dose direct oral factor Xa inhibitors in subjects with atrial fibrillation: a review of clinical evidence

In real-world clinical practice, underdosing, i.e. off-label use of reduced doses (RDs), of oral factor Xa inhibitors (oFXaIs) is quite common in stroke prevention in non-valvular atrial fibrillation, possibly reflecting the hope to increase safety without reducing efficacy in selected patients. To assess whether this strategy is associated with some clinical benefit, we used a physician-centred approach to evaluate whether current evidence supports the hypothesis that a substantial proportion of underdosing may be voluntary rather than casual, whether and to what extent oFXaIs' dose rather than patients' characteristics are associated with bleeding events, and which are the safety and efficacy clinical implications of oFXaIs' underdosing. Our review found consistent evidence that underdosing is often an intentional strategy; however, available studies do not demonstrate a sizeable net clinical benefit of using off-label RD oFXaIs.