A systematic review of network meta-analyses among patients with nonvalvular atrial fibrillation: A comparison of efficacy and safety following treatment with direct oral anticoagulants

Pharmacological Thromboprophylaxis for VTE Post-Endovenous Ablation of Varicose Veins: Network Meta-Analysis

OBJECTIVE

Endovenous ablation has revolutionized treatment of varicose vein surgery but is associated with a risk of venous thromboembolism. There is no consensus regarding anticoagulation protocols for these patients. This network meta-analysis (NMA) aims to identify which anticoagulant is optimal in this cohort for clot prevention with minimal risk of adverse bleeding events.

METHODS

Library databases were searched for studies where patients were treated with one or more anticoagulants following endovenous ablation for varicose veins. The methodological quality of included studies was quantified using the Risk of Bias (ROB) assessment tools. Findings were reported using the meta-analysis of observational studies in epidemiology (MOOSE) checklist. Statistical analysis was carried out using metainsight (rpackage).

RESULTS

Observational data on just under 1500 patients prescribed post ablation anticoagulation (Rivaroxaban, Enoxaparin, Fondaparinux) were analyzed. Patient characteristics were comparable across the cohorts. 81 thrombotic and 40 minor bleeding events occurred in total. Overall rivaroxaban is found to be superior to the other agents.

CONCLUSIONS

This NMA indicates that prophylactic rivaroxaban is the highest ranked anticoagulant for thromboprophylaxis in patients post endovenous ablation for varicose veins, with a low risk of adverse bleeding. The choice whether to anticoagulate these patients is likely to remain at the discretion of the treating clinician.

Comparative Effectiveness and Safety of Apixaban, Rivaroxaban, and Warfarin in Patients With Cirrhosis and Atrial Fibrillation : A Nationwide Cohort Study

BACKGROUND

Apixaban, rivaroxaban, and warfarin have shown benefit for preventing major ischemic events, albeit with increased bleeding risk, among patients in the general population with atrial fibrillation (AF). However, data are scarce in patients with cirrhosis and AF.

OBJECTIVE

To compare the effectiveness and safety of apixaban versus rivaroxaban and versus warfarin in patients with cirrhosis and AF.

DESIGN

Population-based cohort study.

SETTING

Two U.S. claims data sets (Medicare and Optum's de-identified Clinformatics Data Mart Database [2013 to 2022]).

PARTICIPANTS

1:1 propensity score (PS)-matched patients with cirrhosis and nonvalvular AF initiating use of apixaban, rivaroxaban, or warfarin.

MEASUREMENTS

Primary outcomes included ischemic stroke or systemic embolism and major hemorrhage (intracranial hemorrhage or major gastrointestinal bleeding). Database-specific and pooled PS-matched rate differences (RDs) per 1000 person-years (PY) and Cox proportional hazard ratios (HRs) with 95% CIs were estimated, controlling for 104 preexposure covariates.

RESULTS

Rivaroxaban initiators had significantly higher rates of major hemorrhagic events than apixaban initiators (RD, 33.1 per 1000 PY [95% CI, 12.9 to 53.2 per 1000 PY]; HR, 1.47 [CI, 1.11 to 1.94]) but no significant differences in rates of ischemic events or death. Consistently higher rates of major hemorrhage were found with rivaroxaban across subgroup and sensitivity analyses. Warfarin initiators also had significantly higher rates of major hemorrhage than apixaban initiators (RD, 26.1 per 1000 PY [CI, 6.8 to 45.3 per 1000 PY]; HR, 1.38 [CI, 1.03 to 1.84]), particularly hemorrhagic stroke (RD, 9.7 per 1000 PY [CI, 2.2 to 17.2 per 1000 PY]; HR, 2.85 [CI, 1.24 to 6.59]).

LIMITATION

Nonrandomized treatment selection.

CONCLUSION

Among patients with cirrhosis and nonvalvular AF, initiators of rivaroxaban versus apixaban had significantly higher rates of major hemorrhage and similar rates of ischemic events and death. Initiation of warfarin versus apixaban also contributed to significantly higher rates of major hemorrhagic events, including hemorrhagic stroke.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Prescription and switching patterns of direct oral anticoagulants in patients with atrial fibrillation

Background

The patterns of direct oral anticoagulant (DOAC) selection and switching to a different oral anticoagulant (OAC) in patients with atrial fibrillation (AF) are unknown.

Objectives

To describe temporal patterns in first DOAC prescriptions, estimate the incidence, and identify predictors of switching to a different OAC within 1 year in OAC-naive AF patients.

Methods

In this retrospective cohort study, using a near-nationwide prescription registry (IQVIA, the Netherlands), we determined the number of patients per month initiated on each DOAC and identified predictors of switching within 1 year with robust Poisson regression.

Results

We included 94,874 patients. From November 2015 to November 2019, the monthly use of apixaban (n = 366 to n = 1066, +191%), rivaroxaban (n = 379 to n = 868, +129%), and edoxaban (n = 2 to n = 305, +15,150%) increased, whereas that of dabigatran decreased (n = 317 to n = 179, -44%). In the 66,090 patients with ≥1 year of available calendar time, 7% switched to a different OAC within 1 year. Strong predictors of switching to a different DOAC were using dabigatran (adjusted risk ratio [aRR], 3.33; 95% CI, 3.02-3.66) or edoxaban (aRR, 1.56; 95% CI, 1.34-1.82) rather than apixaban and using a standard DOAC dose (aRR, 2.54; 95% CI, 2.23-2.88). Strong predictors of switching to a vitamin K antagonist were using rivaroxaban (aRR, 1.36; 95% CI, 1.19-1.54 vs apixaban) and using a standard DOAC dose (aRR, 1.49; 95% CI, 1.26-1.77).

Conclusion

In the Netherlands, factor Xa inhibitors are increasingly being selected for OAC-naive AF patients. Seven percent of patients switch to a different OAC within 1 year, and the initial DOAC type and dose are strong predictors of switching.

Effects of dabigatran, rivaroxaban, and apixaban on fibrin network permeability, thrombin generation, and fibrinolysis

INTRODUCTION

There are important pharmacological differences between direct oral anticoagulants (DOAC) and a deeper knowledge of how they influence different aspects of hemostasis in patients on treatment is desirable.

MATERIALS AND METHODS

Blood samples from patients on dabigatran (n = 23), rivaroxaban (n = 26), or apixaban (n = 20) were analyzed with a fibrin network permeability assay, a turbidimetric clotting and lysis assay, the calibrated automated thrombogram (CAT), plasma levels of thrombin-antithrombin complex (TAT) and D-dimer, as well as DOAC concentrations, PT-INR and aPTT. As a comparison, we also analyzed samples from 27 patients on treatment with warfarin.

RESULTS

Patients on dabigatran had a more permeable fibrin network, longer lag time (CAT and turbidimetric assay), and lower levels of D-dimer in plasma, compared with patients on rivaroxaban- and apixaban treatment, and a more permeable fibrin network than patients on warfarin. Clot lysis time was slightly longer in patients on dabigatran than in patients on rivaroxaban. Warfarin patients formed a more permeable fibrin network than patients on apixaban, had longer lag time than patients on rivaroxaban (CAT assay), and lower peak thrombin and ETP compared to patients on treatment with both FXa-inhibitors.

CONCLUSIONS

Results from this study indicate dabigatran treatment is a more potent anticoagulant than apixaban and rivaroxaban. However, as these results are not supported by clinical data, they are probably more related to the assays used and highlight the difficulty of measuring and comparing the effect of anticoagulants.

Impact of patient selection in clinical trials: application of ROCKET AF and ARISTOTLE criteria in GARFIELD-AF

BACKGROUND

The extent to which differences in results from Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) and Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial (ROCKET) atrial fibrillation (AF)-the landmark trials for the approval of apixaban and rivaroxaban, respectively, for non-valvular AF-were influenced by differences in their protocols is debated. The potential influence of selection criteria on trial results was assessed by emulating these trials in data from the Global Anticoagulant Registry in the Field (GARFIELD)-AF registry.

METHODS

Vitamin K antagonist (VKA) and non-vitamin K oral antagonist (NOAC) users from GARFIELD-AF were selected according to eligibility for the original ARISTOTLE or ROCKET AF trials. A propensity score overlap weighted Cox model was used to emulate trial randomisation between treatment groups. Adjusted HRs for stroke or systemic embolism (SE) within 2 years of enrolment were calculated for each NOAC versus VKA.

RESULTS

Among patients on apixaban, rivaroxaban and VKA, 2570, 3560 and 8005 were eligible for ARISTOTLE, respectively, and 1612, 2005 and 4368, respectively, for ROCKET AF. When selecting for ARISTOTLE criteria, apixaban users had significantly lower stroke/SE risk versus VKA (HR 0.57; 95% CI 0.34 to 0.94) while no reduction was observed with rivaroxaban (HR 0.98; 95% CI 0.68 to 1.40). When selecting for ROCKET AF criteria, safety and efficacy versus VKA were similar across the NOACs.

CONCLUSION

Apixaban and rivaroxaban showed similar results versus VKA in high-risk patients selected according to ROCKET AF criteria, whereas differences emerged when selecting for the more inclusive ARISTOTLE criteria. Our results highlight the importance of trial selection criteria in interpreting trial results and underline the problems faced in comparing treatments across rather than within clinical trials.

Comparative effectiveness and safety of apixaban and rivaroxaban in older patients with atrial fibrillation: A population-based cohort study

BACKGROUND

There are no clinical trials with a head-to-head comparison between the 2 most commonly used oral anticoagulants (apixaban and rivaroxaban) in patients with atrial fibrillation (AF). The comparative efficacy and safety between these drugs remain unclear, especially in older patients who are at the highest risk for stroke and bleeding.

OBJECTIVE

The purpose of this study was to compare the risk of major bleeding and thromboembolic events between apixaban and rivaroxaban in older patients with AF.

METHODS

We conducted a population-based retrospective cohort study of all adult patients (66 years or older) with AF in Ontario, Canada, who were treated with apixaban or rivaroxaban between April 1, 2011, and March 31, 2020. The primary safety outcome was major bleeding, and the primary efficacy outcome was thromboembolic events. Secondary outcomes included any bleeding. Rates and hazard ratios (HRs) were adjusted for baseline comorbidities with inverse probability of treatment weighting.

RESULTS

This study included 42,617 patients with AF treated with apixaban and 30,725 patients treated with rivaroxaban. After inverse probability of treatment weighting using the propensity score, patients in the apixaban and rivaroxaban groups were well balanced for baseline values of demographic characteristics, comorbidities, and medications; both groups had a similar mean age of 77.4 years, and 49.9% were female. At 1 year, the apixaban group had a lower risk for both major bleeding with an absolute risk reduction at 1 year of 1.1% (2.1% vs 3.2%; HR 0.65; 95% confidence interval [CI] 0.59-0.71]) and any bleeding (8.1% vs 10.9%; HR 0.73; 95% CI 0.69-0.77), with no difference in the risk for thromboembolic events (2.2% vs 2.2%; HR 1.02; 95% CI 0.92-1.13).

CONCLUSION

In patients with AF, 66 years or older, treatment with apixaban was associated with lower risk for major bleeding, with no difference in the risk for thromboembolic events compared with rivaroxaban.

Usefullness of Heparin Calibrated Anti-Xa Activity to Assess Anticoagulant Activity of Apixaban and Rivaroxaban in Emergency Patients Scheduled for Acute Interventions

(1) Background: Direct oral anticoagulants (DOACs) require monitoring in some critical clinical situations. The specific tests for DOAC monitoring are not yet available in all labs. The aim of this study was to evaluate if a unique, more widespread heparin-calibrated anti-Xa assay could be suitable to estimate the concentrations of apixaban and rivaroxaban in order to establish an algorithm helping our clinicians in their therapeutic decision for patients treated with DOACs in emergencies. (2) Methods: A first retrospective part allowed us to determine of a conversion factor between the measured DOAC concentration and the deducted anti-Xa heparin activity based on optic density. During the second prospective part, both DOAC concentration (ng/mL) and anti-Xa activity heparin (UI/mL) were measured on the same sample, and the previously determined conversion factor was applied to each UI/mL value. We then compared the calculated and measured DOAC concentration values. (3) Results: The analysis of the derivation cohort confirmed a good correlation, especially between the anti-Xa heparin activity and the apixaban concentrations (r = 0.97). Additionally, we determined heparin-calibrated anti-Xa assay cut-offs for invasive procedures at 0.3 UI/mL and for intravenous thrombolysis at 0.51 UI/mL using ROC curves with a sensitivity at 98% and specificity at 95% for 0.3 UI/mL and a sensitivity at 97.7% and specificity at 88.2% for the cut-off of 0.51 UI/mL. In the validation cohort, we confirmed the agreement between measured and calculated DOAC concentrations for the low values, especially around cut-offs with an excellent negative predictive value for 0.51 UI/mL (94% for apixaban and 100% for rivaroxaban) and a good negative predictive value for 0.3 UI/mL (83.3% for apixaban and 85.7% for rivaroxaban). (4) Conclusions: Our results confirm that it is possible to correctly predict or exclude the presence of apixaban/rivaroxaban in emergency situations when specific tests are not readily available.

Clinical outcomes in patients with atrial fibrillation and a history of falls using non-vitamin K antagonist oral anticoagulants: A nationwide cohort study

Background

Data on non-vitamin K antagonist oral anticoagulant (NOAC) use in patients with atrial fibrillation (AF) and a history of falls are limited. Therefore, we investigated the impact of a history of falls on AF-related outcomes, and the benefit-risk profiles of NOACs in patients with a history of falls.

Methods

Using Belgian nationwide data, AF patients initiating anticoagulation between 2013 and 2019 were included. Previous falls that occurred ≤ 1 year before anticoagulant initiation were identified.

Results

Among 254,478 AF patients, 18,947 (7.4%) subjects had a history of falls, which was associated with higher risks of all-cause mortality (adjusted hazard ratio (aHR) 1.11, 95%CI (1.06-1.15)), major bleeding (aHR 1.07, 95%CI (1.01-1.14)), intracranial bleeding (aHR 1.30, 95%CI (1.16-1.47)) and new falls (aHR 1.63, 95%CI (1.55-1.71)), but not with thromboembolism. Among subjects with a history of falls, NOACs were associated with lower risks of stroke or systemic embolism (aHR 0.70, 95%CI (0.57-0.87)), ischemic stroke (aHR 0.59, 95%CI (0.45-0.77)) and all-cause mortality (aHR 0.83, 95%CI (0.75-0.92)) compared to vitamin K antagonists (VKAs), while major, intracranial, and gastrointestinal bleeding risks were not significantly different. Major bleeding risks were significantly lower with apixaban (aHR 0.77, 95%CI (0.63-0.94)), but similar with other NOACs compared to VKAs. Apixaban was associated with lower major bleeding risks compared to dabigatran (aHR 0.78, 95%CI (0.62-0.98)), rivaroxaban (aHR 0.78, 95%CI (0.68-0.91)) and edoxaban (aHR 0.74, 95%CI (0.59-0.92)), but mortality risks were higher compared to dabigatran and edoxaban.

Conclusions

A history of falls was an independent predictor of bleeding and death. NOACs had better benefit-risk profiles than VKAs in patients with a history of falls, especially apixaban.

DOACs in the Anticoagulation of Mechanical Valves: A Systematic Review and Future Perspectives

Valvular heart disease is a common disease often necessitating valve replacement. Mechanical heart valves (MHVs) are often used in younger patients because of their longer durability. Their main disadvantage is the need for lifelong anticoagulation. Warfarin is considered a standard treatment, but it is far from perfect. Direct oral anticoagulants (DOACs) are a new and more patient-friendly alternative to warfarin when anticoagulation is required, but have not yet been approved for the indication of mechanical valves.

EVIDENCE ACQUISITION

A literature search of Pubmed, Embase, Web of Science (Core Collection), and Cochrane Library (from inception to May 2023) was performed using a search string that was well defined and not modified during the study. An extensive overview of the search terms used in each database can be found in the Appendix. Only prospective clinical trials were included in this review. A total of 10 publications were included in this review.

RELEVANCE TO CLINICAL PRACTICE

This systematic review summarizes the different types of DOACs and their possible use in the anticoagulation of mechanical valves. We aim to propose future directions in anticoagulation research for mechanical valves.

CONCLUSIONS

DOAC use in MHVs has been halted due to the failure of both dabigatran and apixaban in two major clinical trials. However, rivaroxaban was successful in two small clinical trials. Ample research is still needed to explore new valve designs as well as new anticoagulation targets.

Mapping the characteristics, methodological quality and standards of reporting of network meta-analyses on antithrombotic therapies: An overview

BACKGROUND

Although a large number of network meta-analyses (NMAs) in the field of cardiology are available, little is known about their methodological quality. We aimed to map the characteristics and critically appraised the standards of conduct and evidence reporting of NMAs assessing antithrombotic therapies for the treatment or prophylaxis of heart diseases and cardiac surgical procedures.

METHODS

We systematically searched PubMed and Scopus to identify NMAs comparing the clinical effects of antithrombotic therapies. Overall characteristics of the NMAs were extracted and their reporting quality and methodological quality were evaluated using the PRISMA-NMA checklist and AMSTAR-2, respectively.

RESULTS

We found 86 NMAs published between 2007 and 2022. Comparisons among direct-acting oral anticoagulants were available in 61 (71%) NMAs. Although around 75% of NMAs stated that they followed international guidelines for conduct and reporting, only one third provided a protocol/register. Complete search strategies and publication bias assessment were lacking in around 53% and 59% of studies, respectively. Most NMAs (n = 77, 90%) provided supplemental material; however, only 5 (6%) made the complete raw data available. Network diagrams were depicted in most studies (n = 67, 78%), yet network geometry was described in only 11 (12.8%) of them. Mean adherence to the PRISMA-NMA checklist was 65.1 ± 16.5%. AMSTAR-2 assessment showed 88% of the NMAs had critically low methodological quality.

CONCLUSION

Although there is a wide diffusion of NMA-type studies on antithrombotics for heart diseases, their methodological and reporting quality remains suboptimal. This may reflect fragile clinical practices due to misleading conclusions from critically low-quality NMAs.

Long-term comparative effectiveness and safety of dabigatran, rivaroxaban, apixaban and edoxaban in patients with atrial fibrillation: A nationwide cohort study

Background: Although non-vitamin K antagonist oral anticoagulants (NOACs) are recommended over vitamin K antagonists (VKAs) in atrial fibrillation (AF) management, direct long-term head-to-head comparisons are lacking. Therefore, their risk-benefit profiles were investigated compared to VKAs and between NOACs. Methods: AF patients initiating anticoagulation between 2013-2019 were identified in Belgian nationwide data. Inverse probability of treatment weighted Cox regression was used to investigate effectiveness and safety outcomes and were additionally stratified by NOAC dose. Results: Among 254,478 AF patients (328,796 person-years of follow-up), NOACs were associated with significantly lower risks of stroke or systemic embolism (stroke/SE) (hazard ratio (HR) 0.68, 95% confidence interval (CI) (0.64-0.72)), all-cause mortality (HR 0.76, 95%CI (0.74-0.79)), major or clinically relevant non-major bleeding (MB/CRNMB) (HR 0.94, 95%CI (0.91-0.98)) and intracranial hemorrhage (HR 0.73, 95%CI (0.66-0.79)), but non-significantly different risks of myocardial infarction, gastrointestinal and urogenital bleeding compared to VKAs. Despite similar stroke/SE risks, dabigatran and apixaban were associated with significantly lower MB/CRNMB risks compared to rivaroxaban (HR 0.86, 95%CI (0.83-0.90); HR 0.86, 95%CI (0.83-0.89), respectively) and edoxaban (HR 0.91, 95%CI (0.83-0.99); HR 0.86, 95%CI (0.81-0.91), respectively), and apixaban with significantly lower major bleeding risks compared to dabigatran (HR 0.86, 95%CI (0.80-0.92)) and edoxaban (HR 0.79, 95%CI (0.72-0.86)). However, higher mortality risks were observed in some risk groups including with apixaban in patients with diabetes or concomitantly using digoxin compared to dabigatran and edoxaban, respectively. Conclusion: NOACs had better long-term risk-benefit profiles than VKAs. While effectiveness was comparable, apixaban was overall associated with a more favorable safety profile followed by dabigatran.

Ionized Magnesium: Interpretation and Interest in Atrial Fibrillation

BACKGROUND

Magnesium (Mg) is often used to manage de novo atrial fibrillation (AF) in the emergency department (ED) and intensive care unit (ICU). Point of care measurement of ionized magnesium (iMg) allows a rapid identification of patients with impaired magnesium status, however, unlike ionized calcium, the interpretation of iMg is not entirely understood. Thus, we evaluated iMg reference values, correlation between iMg and plasmatic magnesium (pMg), and the impact of pH and albumin variations on iMg levels. Secondary objectives were to assess the incidence of hypomagnesemia in de novo AF.

METHODS

A total of 236 emergency department and intensive care unit patients with de novo AF, and 198 control patients were included. Reference values were determined in the control population. Correlation and concordance between iMg and pMg were studied using calcium (ionized and plasmatic) as a control in the whole study population. The impact of albumin and pH was assessed in the discordant iMg and pMg values. Lastly, we assessed the incidence of ionized hypomagnesemia (hypoMg) among de novo AF.

RESULTS

The reference range values established in our study for iMg were: 0.48-0.65 mmol/L (the manufacturers were: 0.45-0.60 mmol/L). A strong correlation was observed between pMg and iMg (r = 0.85), but, unlike for calcium values, there was no significant impact of pH and albumin in iMg/pMg interpretation. The incidence of hypoMg among de novo AF patients was 8.5% (12.7% using our ranges). When using our ranges, we found a significant link (p = 0.01) between hyopMg and hypokalemia.

CONCLUSION

We highlight the need for more accurate reference range values of iMg. Furthermore, our results suggest that blood Mg content is not identical to that of calcium. The incidence of ionized hypomagnesemia among de novo AF patients in our study is 8.5%.

Comparison of Effectiveness and Safety Among 3 Direct Oral Anticoagulants in Patients With Venous Thromboembolism - A Single-Center Retrospective Study

Background: Direct oral anticoagulants (DOACs), including edoxaban, rivaroxaban, and apixaban, are administered for the treatment of venous thromboembolism (VTE) in Japan. However, only a few reports have compared the effectiveness and safety of these DOACs. Methods and Results: We retrospectively enrolled 702 patients who received DOACs for VTE treatment between September 2014 and March 2020. We investigated patient demographics, VTE recurrence, major bleeding, and mortality until March 2021, and compared them among the 3 DOACs. Most patients (~70%; n=496) were prescribed edoxaban, followed by apixaban (n=107) and rivaroxaban (n=99). Age, body mass index, renal function, and the proportion of cancer patients did not differ significantly among the DOACs. Edoxaban was administered relatively more in women with low body weight and anemia. The rate of pulmonary embolism was significantly lower among patients receiving edoxaban than apixaban or rivaroxaban (24.4% vs. 41.1% and 53.5%, respectively). VTE reoccurred in 2 patients administered apixaban and 1 patient administered edoxaban. The cumulative incidence of major bleeding at 1 year was 11.7%, 18.5%, and 9.0% in the edoxaban, apixaban, and rivaroxaban groups, respectively. There were no significant differences in the cumulative incidence of major bleeding and all-cause death, estimated by Kaplan-Meier analysis, among the DOACs (log-rank P=0.316 and 0.722, respectively). Conclusions: The safety of the 3 DOACs did not differ significantly in clinical settings, despite differences in patient demographics.

Comparative Effectiveness and Safety Between Apixaban, Dabigatran, Edoxaban, and Rivaroxaban Among Patients With Atrial Fibrillation : A Multinational Population-Based Cohort Study

BACKGROUND

Current guidelines recommend using direct oral anticoagulants (DOACs) over warfarin in patients with atrial fibrillation (AF), but head-to-head trial data do not exist to guide the choice of DOAC.

OBJECTIVE

To do a large-scale comparison between all DOACs (apixaban, dabigatran, edoxaban, and rivaroxaban) in routine clinical practice.

DESIGN

Multinational population-based cohort study.

SETTING

Five standardized electronic health care databases, which covered 221 million people in France, Germany, the United Kingdom, and the United States.

PARTICIPANTS

Patients who were newly diagnosed with AF from 2010 through 2019 and received a new DOAC prescription.

MEASUREMENTS

Database-specific hazard ratios (HRs) of ischemic stroke or systemic embolism, intracranial hemorrhage (ICH), gastrointestinal bleeding (GIB), and all-cause mortality between DOACs were estimated using a Cox regression model stratified by propensity score and pooled using a random-effects model.

RESULTS

A total of 527 226 new DOAC users met the inclusion criteria (apixaban, n = 281 320; dabigatran, n = 61 008; edoxaban, n = 12 722; and rivaroxaban, n = 172 176). Apixaban use was associated with lower risk for GIB than use of dabigatran (HR, 0.81 [95% CI, 0.70 to 0.94]), edoxaban (HR, 0.77 [CI, 0.66 to 0.91]), or rivaroxaban (HR, 0.72 [CI, 0.66 to 0.79]). No substantial differences were observed for other outcomes or DOAC-DOAC comparisons. The results were consistent for patients aged 80 years or older. Consistent associations between lower GIB risk and apixaban versus rivaroxaban were observed among patients receiving the standard dose (HR, 0.72 [CI, 0.64 to 0.82]), those receiving a reduced dose (HR, 0.68 [CI, 0.61 to 0.77]), and those with chronic kidney disease (HR, 0.68 [CI, 0.59 to 0.77]).

LIMITATION

Residual confounding is possible.

CONCLUSION

Among patients with AF, apixaban use was associated with lower risk for GIB and similar rates of ischemic stroke or systemic embolism, ICH, and all-cause mortality compared with dabigatran, edoxaban, and rivaroxaban. This finding was consistent for patients aged 80 years or older and those with chronic kidney disease, who are often underrepresented in clinical trials.

PRIMARY FUNDING SOURCE

None.

Impact of the COVID-19 pandemic on England's national prescriptions of oral vitamin K antagonist (VKA) and direct-acting oral anticoagulants (DOACs): an interrupted time series analysis (January 2019-February 2021)

BACKGROUND

Direct-acting oral anticoagulants (DOACs) were developed as an alternative to warfarin to treat and prevent thromboembolism, including stroke prevention in non-valvular atrial fibrillation patients. The COVID-19 pandemic could increase the risk of stroke and/or the risk of bleeding in patients due to nonadherence or sub/supra-optimal dosing.

OBJECTIVE

To investigate DOAC prescription trends in England's community settings during the complete first wave of COVID-19 pandemic.

METHODS

Descriptive and interrupted time series (ITS) analyses were conducted to examine the prescription patterns of DOACs (dabigatran, rivaroxaban, apixaban and edoxaban) and warfarin for primary care patients in the English Prescribing Dataset from January 2019 to February 2021, with March 2020 as the cut-off point.

RESULTS

A 19% increase in mean DOAC's accompanied with 20% warfarin prescriptions decline was observed. ITS modelling showed an increase in DOAC prescription volume in March 2020 (+7 million items, p = 0.008). The pre-existing upward trend in DOAC prescriptions slowed during the period (-427,000 items, p = 0.007). Apixaban was the most frequently used DOAC and had the largest step-change in March 2020 (+5 million items, p = 0.010). The mean monthly combined cost of DOACs and warfarin was higher during the period. DOAC prescription trends were consistent across England's regions. Conclusion: The overall oral anticoagulants use in this period was lower than expected, indicating a medical needs gap, possibly due to adherence issues. The potential clinical and logistical consequences warrant further study to identify contributing factors and mitigate avoidable risks.

Prescribing direct-acting oral anticoagulants - mind the evidence gap

Direct-acting oral anticoagulants (DOACs) are licensed for the prevention of thromboembolism in non-valvular atrial fibrillation amongst other indications. Prescribers use information derived from the summary of product characteristics which is based on the key trials supporting the DOAC's market authorisation. However, prescribers may not be aware of the limitations within these trials regarding underrepresentation of patient populations commonly encountered in clinical practice and how this may adversely impact them. This review highlights the gaps in the licensing evidence using 4 clinical vignettes that explore prescribing challenges in older adults, female patients, patients with obesity and patients from non-Europid ethnic backgrounds.

Comparative Effectiveness and Safety of Rivaroxaban and Warfarin for Stroke Prevention in Patients with Non-Valvular Atrial Fibrillation in an Omani Tertiary Care Hospital

Objective:

The aim of the study was to compare the effectiveness and safety of rivaroxaban and warfarin as well as to determine the appropriateness of dosing and prescribing of rivaroxaban in Omani patients with non-valvular atrial fibrillation (NVAF).

Methods:

This retrospective cohort study was conducted using the Royal Hospital data registry. The study included all adults newly diagnosed with NVAF and treated with rivaroxaban or warfarin. The outcomes measured include ischaemic stroke, gastrointestinal bleeding (GIB), non-gastrointestinal bleeding (NGIB), as well as appropriateness of dosing and prescribing of rivaroxaban.

Results:

The analysis included 96 rivaroxaban users and 183 warfarin users; 51% of the cohort included males. There were no significant differences observed in the risk of ischaemic stroke between the two groups (hazard ratio (HR), 1.1; 95% confidence interval (CI): 0.4-3.4; p=0.8). However, those on rivaroxaban exhibited a significantly higher rate of GIB compared to those on warfarin (HR, 5.9; 95% CI: 2.9-11.7; p=0.001). There were no differences observed with regards to NGIB between the two groups (HR, 0.9; 95% CI: 0.4-1.9; p=0.8). Dosing and prescribing of rivaroxaban were found to be appropriate in 89% of the patients, with only 6% being prescribed an inappropriately lower dose.

Conclusion:

The study demonstrated no significant differences in the risk of ischaemic stroke or NGIB between rivaroxaban and warfarin groups in newly diagnosed NVAF patients. However, rivaroxaban users were found to have a significantly higher risk of GIB. Rivaroxaban was appropriately prescribed to the majority of the patients, and only a small proportion of the group received an inappropriately lower dose of rivaroxaban.

Direct Oral Anticoagulant removal by a DOAC filter: Impact on lupus anticoagulant testing - Evaluation on spiked and patient samples

Background

DOAC Filter (DF) is a new device to overcome interference in lupus anticoagulant (LAC) testing by direct oral anticoagulants (DOACs).

Objectives

We evaluated DOAC removal from plasma and elimination of DOAC interference in LAC testing by DF, and impact of DF on LAC assays in a representative patient cohort, including a comparison with DOAC-Stop (DS).

Methods

Normal pooled plasma (NPP) was spiked with increasing concentrations of apixaban, rivaroxaban, edoxaban, and dabigatran. DOAC and LAC was measured on untreated, DF-treated, and DS-treated spiked samples. Coagulation parameters and thrombin generation were measured on patient samples (n = 20) before and after DF. Patients treated with DOAC, vitamin K antagonist, or heparin and nonanticoagulated patient samples (n = 139) were tested for LAC before and after DF.

Results

In spiked NPP, levels were below the lower limit of quantification (LLoQ) after DF/DS treatment for all DOAC concentrations. Following DF, levels were below LLoQ for 53 of 56 DOAC-containing patient samples. Twenty-eight of 33 LAC-positive DOAC-containing samples became negative after filtration, whereas 5 remained LAC-positive (1/5 from a patient with antiphospholipid syndrome [APS]). Four LAC-positive DOAC-containing samples (from patients without APS), became negative after filtration, whereas they remained LAC positive after DS. In the non-DOAC patient groups following DF, LAC changed from positive to negative in 8 (due to a procoagulant effect) and vice versa in 2 cases.

Conclusion

DF reduces DOAC interference in LAC testing. As incomplete DOAC removal may occur, DOAC measurements should be performed after filtration. A procoagulant effect after filtration may lead to erroneous LAC results in non-DOAC-containing samples. Therefore, using DF should be restricted to DOAC-containing samples.

Major gastrointestinal bleeding risk with direct oral anticoagulants: Does type and dose matter? - A systematic review and network meta-analysis

The relative risk of major gastrointestinal bleeding (GIB) among different direct oral anticoagulants (DOACs) is debatable. Randomized controlled trials (RCTs) comparing DOACs with each other are lacking. We performed network meta-analysis to assess whether the risk of major GIB differs based on type and dose of DOAC. Literature search of PubMed, EMBASE and Cochrane databases from inception to August 2019, limited to English publications, was conducted to identify RCTs comparing DOACs with warfarin or enoxaparin for any indication. Primary outcome of interest was major GIB risk. We used frequentist network meta-analysis through the random-effects model to compare DOACs with each other and DOACs by dose to isolate the impact on major GIB. Twenty-eight RCTs, including 139 587 patients receiving six anticoagulants, were selected. The risk of major GIB for DOACs was equal to warfarin. Comparison of DOACs with each other did not show risk differences. After accounting for dose, rivaroxaban 20 mg, dabigatran 300 mg and edoxaban 60 mg daily had 47, 40 and 22% higher rates of major GIB versus warfarin, respectively. Apixaban 5 mg twice daily had lower major GIB compared to dabigatran 300 mg (OR, 0.63; 95% CI, 0.44-0.88) and rivaroxaban 20 mg (OR, 0.60; 95% CI, 0.43-0.83) daily. Heterogeneity was low, and the model was consistent without publication bias (Egger's test: P = 0.079). All RCTs were high-quality with low risk of bias. DOACs at standard dose, except apixaban, had a higher risk of major GIB compared to warfarin. Apixaban had a lower rate of major GIB compared to dabigatran and rivaroxaban.

Ischaemic stroke in anticoagulated patients with atrial fibrillation

Anticoagulation substantially reduces the risk of stroke in patients with atrial fibrillation (AF). However, recent studies have shown that up to 22%-36% of patients on anticoagulation will suffer an ischaemic stroke (IS). In this narrative review, we provide an overview of risk factors, mechanisms, management of acute IS and strategies for secondary prevention for patients with AF with stroke despite oral anticoagulation. For this paper, we reviewed available literature from important studies (randomised clinical trials, meta-analyses, reviews and case series) on patients with IS despite anticoagulation. We focused on recent studies that examined safety and efficacy of acute stroke treatments and evaluation and management strategies for secondary prevention. The literature review suggests that patients with AF with IS despite anticoagulation are a heterogeneous group with several possible mechanisms, which may include reduced or non-adherence to anticoagulation, competing non-cardioembolic stroke aetiologies or cardioembolic mechanisms separate from AF. The identification of one or more possible mechanisms of stroke despite anticoagulation may allow for a more targeted and individualised approach for secondary prevention. There are limited data to guide management in such patients, and strategies to prevent recurrent strokes include strict risk factor control and therapies targeting the most likely stroke mechanism. In cases where AF is suspected to be the culprit, clinical trials are needed to test the safety and efficacy of left atrial appendage occlusion plus anticoagulation versus continued anticoagulation alone.

Net clinical benefit of a reduced dose of DOACs in non-valvular atrial fibrillation: A meta-analysis of randomized trials

BACKGROUND

In standard dosing, direct Oral Anticoagulants (DOACs) are used as an alternative to warfarin to prevent ischemic stroke and systemic embolism in non-valvular Atrial Fibrillation (AF). However, randomized comprehensive evidence considering the efficacy and safety of the low-dose DOACs in the same setting is still lacking. Toward this end, we conducted a meta-analysis of randomized trials to estimate the risk/benefit ratio, in terms of net clinical benefit, by comparing a reduced dose of DOACs and warfarin.

METHODS

We searched three electronic databases, covering the period until end-February 2021. All-cause death, non-fatal stroke/systemic embolism, and major bleeding events, with or without the inclusion of myocardial infarction, were used to define two different net clinical benefit outcomes. In addition, we evaluated different component outcomes of net clinical benefit as secondary outcomes. Finally, risk ratios and 95% Confidence Intervals (CI) of each outcome were calculated (random-effects model).

RESULTS

In the four randomized trials included (n = 29,779 patients), the net clinical benefit - with or without the inclusion of myocardial infarction - of low-dose DOACs, compared to warfarin, was a 12% (95% CI, 7%-16%) or a 10% (95% CI, 5%-13%) reduction of events, respectively. Compared to warfarin, the reduced dose of DOACs decreased death outcomes, major bleeding events, and hemorrhagic stroke, whereas all thrombotic outcomes were not different among the groups.

CONCLUSIONS

DOACs at low dosing present a more favorable net clinical benefit profile compared to warfarin.

Switching of oral anticoagulants in patients with non-valvular atrial fibrillation: A narrative review

Approval of direct-acting oral anticoagulants (DOACs) for stroke prevention in atrial fibrillation (AF) was an important milestone, providing a wider range of treatment options and creating the possibility for drug switching after initiation. In addition to improved utilisation of oral anticoagulants (OACs) for stroke prevention, reports of switching among OACs are growing in the literature; switching may influence clinical outcomes, healthcare costs and patient satisfaction. This review aimed to summarise the current literature on the pattern of OAC switching in patients with AF, including reasons for switching and clinical consequences following switching. A literature search was conducted in PubMed, Scopus, and Embase on Jun 27, 2020. We included 39 articles published after 2013, following the introduction of apixaban. The review found that switching among OACs was common in clinical practice, significantly varying with the type of OAC. Studies reporting the reason for switching and clinical outcomes were comparatively limited. The decision to switch was often related to safety issues (usually bleeding), poor anticoagulation control and ease-of-use. Patient characteristics, clinical conditions and drug interactions were found to be associated with switching from OACs. Findings regarding bleeding outcomes following switching were inconsistent, possibly confounded by the rationale for switching and the switching protocol. Noting the limited number of studies included and their relatively short follow-up periods, switching did not have a significant impact on the risk of stroke and other thrombotic outcomes. Further prospective studies are needed to understand better potential rationales for switching and the clinical outcomes.

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.

Prediction and treatment of bleeding in patients under anticoagulant treatment

Major bleeding is a common complication of anticoagulant treatment. Risk assessment tools are relevant in the management of patients with atrial fibrillation and venous thromboembolism. The combination of clinical, biological and genetic markers is incorporated to build predictive scores to help in the decision process about intensity and duration of treatment. The optimal management of bleeding involves the application of predictive scores in combination with anticoagulant reversal strategies.

Safety and Efficacy of Double Antithrombotic Therapy With Non-Vitamin K Antagonist Oral Anticoagulants in Patients With Atrial Fibrillation Undergoing Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis

Background The optimal antithrombotic therapy for patients with atrial fibrillation undergoing percutaneous coronary intervention is a topic of debate. We aimed at defining the efficacy and safety of double antithrombotic therapy with single antiplatelet therapy (SAPT) plus a non-vitamin K antagonist oral anticoagulant (NOAC) against triple antithrombotic therapy with dual antiplatelet therapy (DAPT) added to a vitamin K antagonist (VKA), illustrating the pooled cumulative distribution of events, the ranking of different NOACs tested in NOAC+SAPT combination strategies, and the state of the current evidence in the field. Methods and Results Randomized controlled trials meeting the inclusion criteria were identified. The primary efficacy end point was the composite of trial-defined major adverse cardiac events. The primary safety end point was clinically significant bleeding. Secondary end points were the components of primary end points. Trial-level pairwise and Bayesian network meta-analyses, reconstructed Kaplan-Meier analyses, and trial sequential analysis were performed. Four randomized controlled trials (10 969 patients) were included. No differences were found in terms of major adverse cardiac events (hazard ratio [HR], 1.07; 95% CI, 0.94-1.22), and the NOAC+SAPT strategy showed a lower rate of clinically significant bleeding compared with VKA + DAPT (HR, 0.56; 95% CI, 0.39-0.80). These results were consistent in reconstructed Kaplan-Meier analyses. In the Bayesian network meta-analysis, different NOACs displayed diverse risk-benefit profiles. Trial sequential analyses suggest that the evidence for the similarity in major adverse cardiac events compared with VKA + DAPT and the bleeding risk reduction observed with NOAC+SAPT is likely to be conclusive. Conclusions NOAC+SAPT does not increase the risk of major adverse cardiac events and reduces the risk of bleeding compared with VKA + DAPT in AF patients undergoing percutaneous coronary intervention. Various NOACs may have different risk-benefit profiles in combination strategies. Registration URL: https://www.crd.york.ac.uk/prospero/; Unique identifier: CRD42020151089.

Systematic review and meta-analysis of the efficacy and safety of apixaban compared to rivaroxaban in acute VTE in the real world

Both apixaban and rivaroxaban have been approved for use in acute venous thromboembolism (VTE). Although indirect comparison through network meta-analyses of randomized trials have been performed to compare the efficacy and safety of these agents, further comparison between these agents was lacking until recently. We sought to systematically review and carry out a meta-analysis of studies to further compare apixaban with rivaroxaban from multiple studies done in the real-world settings. Studies comparing rivaroxaban with apixaban in patients with acute VTE were identified through electronic literature searches of MEDLINE, EMBASE, Scopus, and the Cochrane library up to May 2019. Study-specific risk ratios (RRs) were calculated and combined using a random-effects model meta-analysis. In an analysis involving 24 041 patients, recurrent VTE within 6 months occurred in 56 of 4897 patients (1.14%) in the apixaban group and 258 of 19 144 patients (1.35%) in the rivaroxaban group (RR, 0.89; 95% confidence interval [CI], 0.67-1.19; P = .45). Clinically relevant major bleeding occurred in 85 of 11 559 patients (0.74%) in the apixaban group and 350 of 33 909 patients (1.03%) in the rivaroxaban group (RR, 0.73; 95% CI, 0.58-0.93; P = .01). Clinically relevant nonmajor bleeding occurred in 169 of 3417 patients (4.95%) in the apixaban group and 1094 of 12 475 patients (8.77%) in the rivaroxaban group (RR, 0.59; 95% CI, 0.50-0.70; P < .01). Apixaban shows equivalent efficacy in prevention of recurrent VTE but decreased risk of major and minor bleeding events compared with rivaroxaban.

The role of non-vitamin K antagonist oral anticoagulants in Asian patients with atrial fibrillation: A PRISMA-compliant article

BACKGROUND

Given the huge burden of atrial fibrillation (AF) and AF-related stroke in Asia, stroke prevention represents an urgent issue in this region. We herein performed a network meta-analysis to examine the role of non-vitamin K antagonist oral anticoagulants (NOACs) in Asian patients with AF.

METHODS

A systematic search of the publications was conducted in PubMed and Embase databases for eligible studies until July 2019. The odds ratios (ORs) and 95% confidence intervals (CIs) were regarded as the effect estimates. The surface under the cumulative ranking area (SUCRA) for the ranking probabilities was calculated.

RESULTS

A total of 17 studies were included. For comparisons of NOACs vs warfarin, dabigatran (OR = 0.77, 95% CI 0.68-0.86), rivaroxaban (OR = 0.72, 95% CI 0.65-0.81), apixaban (OR = 0.56, 95% CI 0.49-0.65), but not edoxaban reduced the risk of stroke or systemic embolism, wheres dabigatran (OR = 0.56, 95% CI 0.41-0.76), rivaroxaban (OR = 0.66, 95% CI 0.50-0.86), apixaban (OR = 0.49, 95% CI 0.36-0.66), and edoxaban (OR = 0.34, 95% CI 0.24-0.49) decreased the risk of major bleeding. In reducing the risk of stroke or systemic embolism, apixaban and rivaroxaban ranked the best and second best (SUCRA 0.2% and 31.4%, respectively), followed by dabigatran (50.2%), edoxaban (75.2%), and warfarin (93.0%). In reducing the risk of major bleeding, edoxaban, and apixaban ranked the best and second best (1.5% and 30.8%, respectively), followed by dabigatran (48.4%), rivaroxaban (69.2%), and warfarin (100%).

CONCLUSION

NOACs were at least as effective as warfarin, but more safer in Asians with AF. Apixaban was superior to other NOACs for reducing stroke or systemic embolism, while edoxaban showed a better safety profile than other NOACs.

Comparison of readmissions among hospitalized nonvalvular atrial fibrillation patients treated with oral anticoagulants in the United States

Objectives

To compare the risks of 1-month all-cause, major bleeding (MB)-related and stroke-related readmissions and the associated hospital resource use and costs among patients previously hospitalized for nonvalvular atrial fibrillation (NVAF) and treated with warfarin, rivaroxaban, and dabigatran vs apixaban.

Methods

Adult patients hospitalized with NVAF (any discharge diagnosis position) who received apixaban, warfarin, rivaroxaban, or dabigatran during hospitalization were identified from the Premier database (1 January 2013–30 June 2017) and grouped into respective cohorts. Propensity score matching was used to generate cohorts with similar characteristics. In regression analyses the risk of readmissions that occurred within 1 month of discharge were evaluated and the associated length of stay (LOS) and costs compared.

Results

NVAF patients treated with warfarin vs apixaban had significantly greater risk of all-cause (odds ratio [OR] = 1.05; confidence interval [CI] = 1.02–1.08; p < .001), MB-related (OR: 1.28; CI: 1.16–1.42; p < .001), and stroke-related (OR: 1.33; CI: 1.11–1.58; p = .002) readmissions; for all readmission categories, average LOS was significantly longer and costs significantly higher for warfarin treated patients. NVAF patients treated with rivaroxaban versus apixaban had significantly greater risk of all-cause (OR: 1.06; CI: 1.02–1.09; p = .001) and MB-related (OR = 1.62; CI = 1.44–1.83; p < .001) readmissions, but not stroke-related readmission; for MB-related readmissions average LOS and costs were higher for rivaroxaban treated patients. Significant differences in risks of all-cause, MB-related, and stroke-related readmissions were not observed between the apixaban and dabigatran cohorts.

Conclusion

In this retrospective real-world analysis of NVAF patients, apixaban treatment was associated with better clinical outcomes than warfarin or rivaroxaban and lower hospital resource burden.

Safety and Efficacy of Oral Anticoagulants Therapies in Patients With Atrial Fibrillation Undergoing Percutaneous Coronary Intervention: A Network Meta-Analysis

Background:

Different antithrombotic treatments, from vitamin K antagonists to direct oral anticoagulants (DOACs), are available to reduce ischemic risks in patients with atrial fibrillation (AF) after percutaneous coronary intervention (PCI). Objective: To synthetize evidence about the benefit–risk ratio of antithrombotic treatments and their combinations in patients with AF and PCI.

Methods:

A network meta-analysis and a stochastic multicriteria acceptability analysis (SMAA) were performed including randomized controlled trials (RCT) that evaluate antithrombotic treatments in adults with AF and PCI. Searches were conducted in PubMed and Scopus (updated November-2019). Outcomes compared included bleeding, stroke, and death (Prospero registration: CRD42019146813).

Results:

Five RCTs were included (11 532 patients). Vitamin K antagonists + dual antiplatelet therapy was associated with major bleeding (odds ratio: 0.52 [95% CI: 0.32-0.86]) compared to DOAC + P2Y12. No statistical differences were found among DOAC regimens for the main outcomes, including bleeding, stroke, and death. Surface under the cumulative ranking curve analysis (SUCRA) and SMAA demonstrated edoxaban 60 mg + P2Y12 inhibitor as the worst option (28%). Apixaban 5 mg + P2Y12 inhibitor was the safest alternative (63%) in all scenarios.

Conclusions:

Insufficient evidence on the clinical superiority among anticoagulant regimens exists, although apixaban slightly stands out. Edoxaban was associated with more adverse events. To strength this evidence, well-designed, low risk of bias clinical trials are needed. Cost-minimization analyses are required to provide further information for clinical decision-making.

Effectiveness and Safety of Apixaban Compared With Rivaroxaban for Patients With Atrial Fibrillation in Routine Practice: A Cohort Study

Background

Apixaban and rivaroxaban are the most commonly prescribed direct oral anticoagulants for adults with atrial fibrillation, but head-to-head data comparing their safety and effectiveness are lacking.

Objective

To compare the safety and effectiveness of apixaban versus rivaroxaban for patients with nonvalvular atrial fibrillation.

Design

New-user, active-comparator, retrospective cohort study.

Setting

A U.S. nationwide commercial health care claims database from 28 December 2012 to 1 January 2019.

Patients

Adults newly prescribed apixaban (n = 59 172) or rivaroxaban (n = 40 706).

Measurements

The primary effectiveness outcome was a composite of ischemic stroke or systemic embolism. The primary safety outcome was a composite of intracranial hemorrhage or gastrointestinal bleeding.

Results

39 351 patients newly prescribed apixaban were propensity score matched to 39 351 patients newly prescribed rivaroxaban. Mean age was 69 years, 40% of patients were women, and mean follow-up was 288 days for new apixaban users and 291 days for new rivaroxaban users. The incidence rate of ischemic stroke or systemic embolism was 6.6 per 1000 person-years for adults prescribed apixaban compared with 8.0 per 1000 person-years for those prescribed rivaroxaban (hazard ratio [HR], 0.82 [95% CI, 0.68 to 0.98]; rate difference, 1.4 fewer events per 1000 person-years [CI, 0.0 to 2.7]). Adults prescribed apixaban also had a lower rate of gastrointestinal bleeding or intracranial hemorrhage (12.9 per 1000 person-years) compared with those prescribed rivaroxaban (21.9 per 1000 person-years), corresponding to an HR of 0.58 (CI, 0.52 to 0.66) and a rate difference of 9.0 fewer events per 1000 person-years (CI, 6.9 to 11.1).

Limitation

Unmeasured confounding, incomplete laboratory data.

Conclusion

In routine care, adults with atrial fibrillation prescribed apixaban had a lower rate of both ischemic stroke or systemic embolism and bleeding compared with those prescribed rivaroxaban.

Primary Funding Source

Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women's Hospital.

Real-life behaviour of direct oral anticoagulants in a Spanish cohort with non-valvular atrial fibrillation: Refase Registry

Aim: To analyse the effectiveness and safety of DOAC (direct oral anticoagulants) in non-valvular atrial fibrillation (NVAF) patients attending clinical practice.Methods: Retrospective study of AF patients who started treatment with DOAC from January 1, 2013 to December 31, 2016 in three Spanish hospitals. Mean follow-up was 1.6 years. The primary outcomes were rates of all-cause death, ischaemic stroke, and bleeding. These outcomes were also studied depending on correct dosage adjustment and standard/adjusted dose.Results: The study included 2494 patients (age = 76.0 ± 9.5 years, CHA₂DS₂-VASc = 4.0 ± 1.6). The most prescribed DOAC was rivaroxaban (41.1%). Patients taking dabigatran were the youngest (mean age = 73.1 ± 10.3 years), with better kidney function (mean CrCl = 80.6 ± 35.8 ml/min) and lower CHA₂DS₂-VASc (3.7 ± 1.4) and HAS-BLED (2.1 ± 0.9) scores. Patients taking apixaban were the oldest, and had the highest CHA2DS2-VASc and HAS-BLED scores (4.3 ± 1.6 and 2.6 ± 0.9, respectively). Rates of stroke/major bleeding/intracranial bleeding were 1.8/3.0/0.3 events per 100 patient-years, respectively, with no differences among DOAC. Based on dose adjustment according to technical data, it was observed that 517 patients (23.5%) received DOAC doses inconsistent with labelling (p < .001) and, within this group, under-dosed patients had a higher death rate although it did not reach a significant result after multivariate adjustment.Conclusions: The results of safety and efficacy are very similar to those of other previously published national registries. There were no differences among the different types of DOAC regarding outcomes. However, it was found that people taking the adjusted dose of the drug seemed to have a higher risk of death. A non-negligible proportion of patients received DOAC doses inconsistent with labelling (mostly underdose).

Costs of gastrointestinal bleeding events in atrial fibrillation: a UK Clinical Practice Research Datalink study

Aim: To estimate the healthcare costs attributable to gastrointestinal (GI) bleeds in nonvalvular atrial fibrillation (NVAF) patients. Material & methods: A difference-in-differences approach was used in which NVAF patients suffering a (GI) bleed were propensity score matched to those not suffering a GI bleed, and the difference in healthcare costs in the year prior to the GI bleed and the subsequent 3 years was compared between the two groups. Results: The mean cost attributable to GI bleeds was £3989 (p < 0.0001) in the year of the bleed and £1816 (p = 0.001) in the subsequent year. Attributable costs arose primarily from inpatient visits. Conclusion: GI bleeds among NVAF patients are associated with significant healthcare costs up to 2 years following the bleed.

Routine Coagulation Tests in Patients With Nonvalvular Atrial Fibrillation Under Dabigatran and Rivaroxaban Therapy: An Affordable and Reliable Strategy?

Dabigatran and rivaroxaban, direct oral anticoagulants (DOACs), affect coagulation tests, and knowledge of their effects is important for therapeutic monitoring. Our aim was to examine the association between DOAC levels and routine coagulation tests in patients with nonvalvular atrial fibrillation. Samples from patients receiving dabigatran (150 mg) and patients receiving rivaroxaban (20 mg) were collected 2 hours after drug intake. Direct oral anticoagulant concentrations were determined using direct Hemoclot thrombin inhibitor (HTI) assay (HTI test) and a direct Xa inhibitor (Anti Xa-Riva). The routine coagulation measured included activated partial thromboplastin time (aPTT) and prothrombin time (PT). The median plasmatic dabigatran was 128.3 ng/mL (95% confidence interval [CI]: 93.7-222.6 ng/mL). The HTI exhibited a good correlation with aPTT (R² = 0.74; P < .0001). The median plasmatic rivaroxaban was 223.9 ng/mL (95% CI: 212.3-238.9 ng/mL). Anti-Xa-Riva correlated with PT (R² = 0.69, P< .0001) and aPTT (R² = 0.36, P < .001), but prolonged PT results were obtained, even below the rivaroxaban therapeutic range (20%). The routine coagulation tests were able to identify out of therapeutic range concentrations for dabigatran and rivaroxaban. We suggest the use of these screening tests to better understand and monitor the subtherapeutic concentrations of these DOACs.

Anti-Xa Oral Anticoagulant Plasma Concentration Assay in Real Life: Rivaroxaban and Apixaban Quantification in Emergency With LMWH Calibrator

BACKGROUND

Oral anti-Xa inhibitors have demonstrated noninferiority to vitamin K antagonists (VKAs) for the prevention of stroke in patients with atrial fibrillation and recurrent venous thromboembolism. They are associated with a decrease in major bleeding. In contrast with VKA, no coagulation monitoring is required. However, in clinical practice, determination of drug concentration is sometimes necessary.

OBJECTIVE

The objective of this study was to evaluate a low-molecular-weight heparin (LMWH) calibrated anti-Xa assay for the quantification of rivaroxaban and apixaban plasma concentration in emergency.

METHODS

The anti-Xa plasma concentration of rivaroxaban and apixaban were measured in emergency in 210 patients using STA anti-Xa liquid assay. For each plasma concentration <150 ng/mL of rivaroxaban or apixaban, an anti-Xa assay calibrated with LMWH was performed.

RESULTS

We demonstrated a significant correlation between LMWH anti-Xa activity and rivaroxaban ( R² = 0.947) or apixaban ( R² = 0.959) concentration and a significant correlation between rivaroxaban and apixaban plasma concentration ( R² = 0.972). A LMWH anti-Xa activity <0.50 IU/mL could exclude a plasma concentration of rivaroxaban and apixaban >30 ng/mL and indicate the feasibility of invasive procedure. Conclusion and Relevance: In the absence of a specific test, LMWH-calibrated anti-Xa assay could be used to determine the presence and evaluate the plasma concentration of oral anti-Xa inhibitors. However, these initial findings require confirmation using other chromogenic calibrated oral anti-Xa assays.