New oral anticoagulants in patients with nonvalvular atrial fibrillation: a review of pharmacokinetics, safety, efficacy, quality of life, and cost effectiveness

Cost-Effectiveness and Budget Impact Analysis of Apixaban and Rivaroxaban Versus Warfarin in the Prevention of Stroke in Patients With Non-Valvular Atrial Fibrillation (NVAF) in Iran

INTRODUCTION

This study evaluates the cost-effectiveness of Apixaban and Rivaroxaban, compared to Warfarin, for stroke prevention in patients with non-valvular atrial fibrillation in Iran.

METHOD

A Markov model with a 30-year time horizon was employed to simulate and assess different treatment strategies' cost-effectiveness. The study population comprised Iranian adults with NVAF, identified through specialist consultations, hospital visits, and archival record reviews. Direct medical costs, direct nonmedical, and indirect costs were included. Quality-adjusted life years (QALY) were assessed using an EQ-5D questionnaire. This study utilized a cost-effectiveness threshold of $11 134 per QALY.

RESULTS

Apixaban demonstrated superior cost-effectiveness compared to Rivaroxaban and Warfarin. Over 30 years, total costs were lower in the Apixaban and Rivaroxaban groups compared to the Warfarin group ($126.18 and $109.99 vs. $150.49). However, Apixaban showed higher total QALYs gained compared to others (0.134 vs. 0.133 and 0.116). The incremental cost-effectiveness ratio for comparing Apixaban to Warfarin was calculated at -1332.83 cost per QALY, below the threshold of $11 134, indicating Apixaban's cost-effectiveness. Sensitivity analyses confirmed the robustness of the findings, with ICER consistently remaining below the threshold. Over 5 years (2024-2028) of Apixaban usage, the incremental cost starts at USD 70 250 296 in the first year and gradually rises to USD 71 770 662 in the fifth year. DSA and PSA were assessed to prove the robustness of the results.

CONCLUSION

This study shows that Apixaban is a cost-effective option for stroke prevention in non-valvular atrial fibrillation patients in Iran compared to Warfarin.

Measurement of apixaban concentrations in different human biological fluids by UHPLC-MS/MS. Clinical pharmacokinetic application in a subject with chronic kidney disease and nonvalvular atrial fibrillation on haemodialysis

BACKGROUND

Apixaban's technical sheet does not recommend its use in clinical practice for patients with chronic kidney disease undergoing haemodialysis. However, recent studies indicate that apixaban could be a safe oral anticoagulant in these kinds of patients who do not present valvular atrial fibrillation. We developed and validated ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) procedures for measuring apixaban concentrations in plasma, dialysate liquid, and urine.

MATERIAL AND METHODS

Simple protein precipitation was implemented to prepare samples. Chromatographic separations were achieved on an Acquity®-UPLC®-BEHTM (2.1x100 mm id, 1.7 µm) reverse-phase C18 column using a water/acetonitrile non-linear gradient containing 0.1 % formic acid at a 0.4 mL/min flow rate. Apixaban and its internal standard (apixaban-d3) were detected by electrospray ionisation mass spectrometry in positive and multiple reaction monitoring modes, using transitions of 460.3 → 199.0/443.2 and 463.3 → 202.0, respectively.

RESULTS

No significant interferences and carry-overs were observed. Precisions, absolute relative biases, normalised-matrix factors, and normalised recoveries were ≤ 12.2%, ≤8.0%, 94.3-105.1%, and 93.9-105.4%, respectively. Linearity was observed between 5 and 500 μg/L for plasma/dialysate liquid and 5-1000 μg/L for urine.

CONCLUSIONS

The validated UHPLC-MS/MS procedures could help support a pharmacokinetic study in non-valvular atrial fibrillation subjects with chronic kidney disease undergoing haemodialysis and apixaban-based anticoagulant therapy.

Characteristics associated with poor atrial fibrillation-related quality of life in adults with atrial fibrillation

PURPOSE

Few studies have examined the relationship between poor atrial fibrillation-related quality of life (AFQoL) and a battery of geriatric factors. The objective of this study is to describe factors associated with poor AFQoL in older adults with atrial fibrillation (AF) with a focus on sociodemographic and clinical factors and a battery of geriatric factors.

METHODS

Cross-sectional analysis of a prospective cohort study of participants aged 65+ with high stroke risk and AF. AFQoL was measured using the validated Atrial Fibrillation Effect on Quality of Life (score 0-100) and categorized as poor (<80) or good (80-100). Chi-square and t -tests evaluated differences in factors across poor AFQoL and significant characteristics ( P  < 0.05) were entered into a logistic regression model to identify variables related to poor AFQoL.

RESULTS

Of 1244 participants (mean age 75.5), 42% reported poor AFQoL. Falls in the past 6 months, pre/frail and frailty, depression, anxiety, social isolation, vision impairment, oral anticoagulant therapy, rhythm control, chronic obstructive pulmonary disease and polypharmacy were associated with higher odds of poor AFQoL. Marriage and college education were associated with a lower odds of poor AFQoL.

CONCLUSIONS

More than 4 out of 10 older adults with AF reported poor AFQoL. Geriatric factors associated with higher odds of reporting poor AFQoL include recent falls, frailty, depression, anxiety, social isolation and vision impairment. Findings from this study may help clinicians screen for patients with poor AFQoL who could benefit from tailored management to ensure the delivery of patient-centered care and improved well being among older adults with AF.

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.

Direct oral anticoagulants (DOACs): From the laboratory point of view

Direct oral anticoagulants (DOACs) represent a new generation of drugs that have been increasingly used in the prevention and treatment of thromboembolic states. According to the mechanism of anticoagulant action, DOACs are divided into two groups: direct inhibitors of thrombin (dabigatran) and direct inhibitors of activated factor X (FXa) (rivaroxaban, apixaban, edoxaban, betrixaban). Compared to the vitamin K antagonists, DOACs are superior in terms of onset of action, pharmacokinetic and pharmacodynamics properties and fixed daily dose without the need for routine coagulation monitoring. Despite these advantages, there are clinical conditions in which laboratory measurement of DOACs should be performed. Although DOACs have an impact on screening haemostasis assays (prothrombin time, PT; activated partial thromboplastin time, aPTT; and thrombin time, TT), these tests are not appropriate for quantifying drug levels. Therefore, specific quantitative methods (LC-MS/MS as a gold standard method for all DOACs, coagulometric and chromogenic assays for dabigatran, and chromogenic anti-Xa assays with drug-specific calibrators for inhibitors of FXa) should only be used for determination of DOACs concentration. The aim of this review is to present all aspects of laboratory assessment of DOACs, including pre-analytical, analytical and post-analytical factors in the overall testing process with a special accent on the available specific quantitative methods for measurement of DOACs in circulation.

Comparative Analysis of Risk Stratification Scores in Atrial Fibrillation

BACKGROUND

Atrial Fibrillation (AF) has become a major global health concern and is associated with an increased risk of poor outcomes. Identifying risk factors in patients with AF can be challenging, given the high burden of comorbidities in these patients. Risk stratification schemes appear to facilitate accurate prediction of outcomes and assist therapeutic management decisions.

OBJECTIVE

To summarize current evidence on risk stratification scores for patients with AF.

RESULTS

Traditional risk models rely heavily on demographics and comorbidities, while newer tools have been gradually focusing on novel biomarkers and diagnostic imaging to facilitate more personalized risk assessment. Several studies have been conducted to compare existing risk schemes and identify specific patient populations in which the prognostic ability of each scheme excels. However, current guidelines do not appear to encourage the implementation of risk models in clinical practice, as they have not incorporated new ones in their recommendations for the management of patients with AF for almost a decade.

CONCLUSION

Further work is warranted to analyze new reliable risk stratification schemes and optimally implement them into routine clinical life.

Gastrointestinal Bleeding and Direct Oral Anticoagulants among Patients with Atrial Fibrillation: Risk, Prevention, Management, and Quality of Life

A significant problem for patients undergoing oral anticoagulation therapy is gastrointestinal bleeding (GIB), a problem that has become increasingly urgent following the introduction of direct oral anticoagulants (DOACs). Furthermore, in recent years a greater focus has been placed on the quality of life (QOL) of patients on long-term oral anticoagulant therapy, which necessitates changes in lifestyle, as well as posing an increased risk of bleeding without producing objective symptomatic relief. Here, we examine current evidence linked to GIB associated with oral anticoagulants, with a focus on randomized control trials, meta-analyses, and postmarketing observational studies. Rivaroxaban and dabigatran (especially the 150-mg bis-in-die dose) appeared to be linked to an increased risk of GIB. The risk of GIB was also greater when edoxaban was used, although this was dependent on the dose. Apixaban did not pose a higher risk of GIB in comparison with warfarin. We provided a summary of current knowledge regarding GIB risk factors for individual anticoagulants, prevention strategies that lower the risk of GIB and management of DOAC therapy after a GIB episode.

Quality of life in patients with nonvalvular atrial fibrillation treated with oral anticoagulants

OBJECTIVES

Health-related quality of life (HRQL) is a key factor in making anticoagulant treatment decisions. The objective of this study was to assess the HRQL of patients with nonvalvular atrial fibrillation by treatment type: direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs).

METHODS

We carried out a cross-sectional observational study with clinical practice data, gathering demographic and clinical variables. HRQL was measured using the 5-level 5-dimension EuroQol questionnaire (EQ-5D-5L). Differences between the study groups in HRQL as measured by the EQ-5D-5L were analyzed using two-part multivariate regression models. First, using logistic regression, the adjusted probability, p(x), of having perfect health was estimated in each subgroup. Secondly, generalized linear models were used to estimate mean disutility values, w(x), in a population that does not have perfect health, i.e. utility less than 1 or 1-w(x).

RESULTS

We recruited 333 patients, of whom 126 were on DOACs and 207 on VKAs. A significant difference was observed in the EQ-5D-5L anxiety/depression dimension, with a higher percentage of patients classified in the 'no problems' category in the DOAC group. The same type of analysis did not identify significant differences in any of the other dimensions (mobility, self-care, usual activities or pain/discomfort).

DISCUSSION

In the multivariate model, utility was significantly higher in the DOAC group than in the VKA group, although the difference was small (0.0121). This difference is attributable to patients on DOACs having less anxiety/depression.

CONCLUSION

Patients treated with DOACs report a slightly better quality of life than those treated with VKAs.

Adherence to direct oral anticoagulant treatment for atrial fibrillation in the Netherlands: A surveillance study

BACKGROUND

Adherence to direct oral anticoagulants (DOACs) in patients with atrial fibrillation in every day practice may be less than in clinical trials.

AIMS

To assess adherence to DOACs in atrial fibrillation patients in every day practice and identify predictors for non-adherence.

METHODS

Individual linked dispensing data of atrial fibrillation patients who used DOACs were obtained from the Foundation for Pharmaceutical Statistics covering the Netherlands between 2012 and 2016. One year adherence to DOAC was calculated for initial DOAC as proportion of days covered (PDC) ≥80% and the association between clinical variables and adherence was assessed using logistic regression. In addition, we measured non-persistence, that is, patients who completely stopped their initial DOAC within 1 year follow-up.

RESULTS

A total of 4797 apixaban-, 20 454 rivaroxaban- and 18 477 dabigatran users were included. The mean age was 69 years (n = 43 910), which was similar for the DOAC types. The overall proportion of patients with PDC ≥80% was 76%, which was highest for apixaban- (87%), followed by dabigatran- (80%) and rivaroxaban (69%) users. Multivariable analyses revealed that age ≤60 years, no concomitant drug use were predictors for non-adherence. Of atrial fibrillation patients who continued treatment, 97% had a PDC ≥80%, compared with only 56% for those who discontinued their DOAC treatment within 1 year.

CONCLUSIONS

Non-adherence to DOACs was associated with age ≤60 years and no concomitant drugs use. Non-adherence was higher in patients who later discontinued DOAC treatment. Results of our study support research into interventions to improve adherence.

Rivaroxaban for the treatment of cerebral venous thrombosis

BACKGROUND

New Oral Anticoagulants (NOACs) such as Rivaroxaban are introduced as alternatives to conventional vitamin-K antagonists in the long-term treatment of thrombotic events due to their lower bleeding risk. There is a lack of evidence on the effectiveness and safety of Rivaroxaban in Cerebral venous thrombosis (CVT). This study aims to assess the effectiveness and bleeding risk of Rivaroxaban in comparison with Warfarin for the treatment of CVT.

MATERIALS AND METHODS

36 patients with diagnosis of CVT were included. Clinical and background information was assessed on admission and patients were followed for at least 12 months. Measured outcomes were modified Rankin Scale (mRS), evidence of recanalization on contrast-enhanced Brain MR venography (MRV) and major or minor bleeding. Patients were divided into two groups according to the type of oral anticoagulant (Rivaroxaban vs Warfarin). Groups were compared in terms of final outcomes and side effects.

RESULT

Overall, 13 (36.11%) patients received Warfarin and 23 (63.89%) received Rivaroxaban. Optimal mRS score (0-1) was attained in 9 of 10 (90%) of patients treated with Rivaroxaban and 19 of 22 (86.36%) of patients received Warfarin. MRV showed complete or partial recanalization in 12 of 14 (85.71%) patients treated with Rivaroxaban and all patients in the Warfarin group. There was no significant difference between the two groups in terms of major and minor hemorrhage.

CONCLUSION

Rivaroxaban holds promise for the treatment of CVT.

Muscle Mass and Direct Oral Anticoagulant Activity in Older Adults With Atrial Fibrillation

BACKGROUND

Direct oral anticoagulants (DOAC) are hydrophilic drugs with plasma levels inversely proportional to lean body mass. Sarcopenic patients with low muscle mass may be at risk for supra-therapeutic DOAC levels and bleeding complications. We therefore sought to examine the influence of lean body mass on DOAC levels in older adults with atrial fibrillation (AF).

METHODS

A prospective cohort study was conducted with patients 65 years of age or more receiving rivaroxaban or apixaban for AF. Appendicular lean mass (ALM) was measured using a bioimpedance device and a dual X-ray absorptiometry scanner. DOAC levels were measured using a standardized anti-Xa assay 4 hours after (peak) and 1 hour before (trough) ingestion.

RESULTS

The cohort consisted of 62 patients (47% female, 77.0 ± 6.1 years). The prescribed DOACs were apixaban 2.5 mg (21%), apixaban 5 mg (53%), and rivaroxaban 20 mg (26%). Overall, 16% had supra-therapeutic DOAC levels at trough and 25% at peak. In the multivariable logistic regression model, lower ALM was independently associated with supra-therapeutic DOAC levels at trough (odds ratio per ↓ 1-kg 1.23, 95% confidence interval 1.02 to 1.49) and peak (odds ratio per ↓ 1-kg 1.18, 95% confidence interval 1.02 to 1.37). Addition of ALM to a model consisting of age, total body weight, and renal function resulted in improved discrimination for supra-therapeutic DOAC levels.

CONCLUSION

Our proof-of-concept study has identified an association between ALM and DOAC levels in older adults with AF. Further research is needed to determine the impact of ALM on bleeding complications and the potential role of ALM-guided dosing for sarcopenic patients.

Health-related quality of life in nonvalvular atrial fibrillation patients with controlled or uncontrolled anticoagulation status

BACKGROUND

There is a dearth of evidence regarding Health-Related Quality of Life (HRQoL) in nonvalvular atrial fibrillation (NVAF) patients undergoing oral anticoagulation therapy. Our objective was to describe HRQoL in NVAF patients on oral anticoagulation, focusing on uncontrolled patients on vitamin K antagonists (VKAs) versus controlled patients on VKAs or non-vitamin K antagonist oral anticoagulants (NOACs), in a real-world setting. Additionally, we assessed the clinical characteristics of patients with uncontrolled anticoagulation.

METHODS

An observational, multicentre, and cross-sectional study, enrolling 38 Spanish Hospitals' Internal Medicine Departments. HRQoL was assessed using the validated Spanish version of the Sawicki questionnaire. High self-perceived HRQoL was indicated by high scores in the general treatment satisfaction and self-efficacy dimensions, and by low scores in the strained social network, daily hassles and distress dimensions.

RESULTS

Five hundred and one patients were included for assessment. Mean scores ± SD were closer to a high perceived HRQoL in controlled than uncontrolled patients for the five dimensions of the questionnaire: 4.9 ± 1.0 versus 3.6 ± 1.3 for general treatment satisfaction; 4.3 ± 1.0 versus 3.6 ± 1.0 for self-efficacy, 3.1 ± 0.9 versus 3.9 ± 1.1 for strained social network, 2.1 ± 0.8 versus 3.0 ± 1.0 for daily hassles and 1.8 ± 0.9 versus 2.6 ± 1.2 for distress.

CONCLUSIONS

HRQoL in patients with controlled anticoagulant status treated with NOACs or VKAs was better than in patients with uncontrolled anticoagulant status. This seems to indicate that anticoagulation control status influences perception of HRQoL, highlighting the importance of its evaluation when assessing HRQoL in NVAF patients.

Satisfaction of Patients with Nonvitamin K Anticoagulants Compared to Vitamin K Antagonists: a Systematic Review and Meta-analysis

OBJECTIVE

 To undertake a systematic review and meta-analysis to assess the satisfaction of patients receiving nonvitamin K anticoagulants (NOACs), compared with vitamin K antagonists (VKAs).

METHODS

 We searched CENTRAL, MEDLINE, Embase, and Clinicaltrials.gov for randomized controlled trials (RCTs) and observational studies. Two reviewers screened, extracted, and appraised data independently. We pooled data using a random-effects model. Outcome included treatment satisfaction, which was assessed by scores of Duke Anticoagulation Satisfaction Scale (DASS), Anticlot Treatment Scale (ACTS), Perception of Anticoagulant Treatment Questionnaire 2 (PACT-Q2), or Treatment Satisfaction Questionnaire for Medication version II (TSQM-VII) and their domains reported with 95% confidence intervals (95% CIs). We followed MOOSE and PRISMA guidelines.

RESULTS

 We included four RCTs and 16 observational studies, enrolling 18,684 participants overall. Compared with VKAs, treatment with NOACs improved the ACTS Burdens score by 4.21 points (95% CI: 2.99-5.43, I ² = 95%, combined n = 6,180), and ACTS Benefits by 0.49 points (95% CI: 0.18-0.81, I ² = 85%, combined n = 6,171). Switching from VKAs to NOACs improved the ACTS Burdens score by 5.33 points (95% CI: 3.53-7.14, combined n = 3,097). Compared with VKAs, treatment with NOACs improved the TSQM-VII Global Satisfaction score by 6.86 points (95% CI: 3.00-10.73, combined n = 5,535).

CONCLUSION

 In patients with nonvalvular atrial fibrillation or venous thromboembolism, NOAC treatment is associated with greater satisfaction compared with VKAs. The switch from VKAs to NOACs was associated with improved patients' satisfaction. These effects were largely due to a lower degree of treatment burden with NOAC treatment.

Drug-drug interaction of rivaroxaban and calcium channel blockers in patients aged 80 years and older with nonvalvular atrial fibrillation

Objectives For revealing the peculiarities of the drug-drug interaction of rivaroxaban (substrate CYP3A4 and P-gp) and calcium channel blockers (CCBs) (verapamil - inhibitor CYP3A4 and P-gp and amlodipine - substrate CYP3A4) in patients 80 years and older with nonvalvular atrial fibrillation (NAF) we studied 128 patients. Methods All patients were divided into groups depending on the therapy taken: the 1st - rivaroxaban + amlodipine (n=51), the 2nd - rivaroxaban + verapamil (n=30), the control group - rivaroxaban without CCBs (n=47). A trough steady-state plasma concentration (C min,ss) of rivaroxaban, prothrombin time (PT) in the blood plasma and the event of clinically relevant non-major (CRNM) bleeding were assessed for each patient. Results Patient in group 2 had higher C min,ss of rivaroxaban, PT and CRNM than subjects in the control group (Me 73.8 [50.6-108.8] ng/mL vs. 40.5 [25.6-74.3] ng/mL; Me 14.8 [13.4-17.3] s vs. 13.8 [12.6-14.4] s; 34% vs. 13%, respectively, p<0.05 for all). When compared, the PT and complication rate in group 1 with the control group C min,ss of rivaroxaban were practically the same (p>0.05 for all). Conclusions In patients ≥80 years with NAF, the use of rivaroxaban in combination with verapamil may not be safe and can lead to CRNM bleeding.

Drug-drug interaction of rivaroxaban and calcium channel blockers in patients aged 80 years and older with nonvalvular atrial fibrillation

Objectives For revealing the peculiarities of the drug-drug interaction of rivaroxaban (substrate CYP3A4 and P-gp) and calcium channel blockers (CCBs) (verapamil - inhibitor CYP3A4 and P-gp and amlodipine - substrate CYP3A4) in patients 80 years and older with nonvalvular atrial fibrillation (NAF) we studied 128 patients. Methods All patients were divided into groups depending on the therapy taken: the 1st - rivaroxaban + amlodipine (n=51), the 2nd - rivaroxaban + verapamil (n=30), the control group - rivaroxaban without CCBs (n=47). A trough steady-state plasma concentration (C min,ss) of rivaroxaban, prothrombin time (PT) in the blood plasma and the event of clinically relevant non-major (CRNM) bleeding were assessed for each patient. Results Patient in group 2 had higher C min,ss of rivaroxaban, PT and CRNM than subjects in the control group (Me 73.8 [50.6-108.8] ng/mL vs. 40.5 [25.6-74.3] ng/mL; Me 14.8 [13.4-17.3] s vs. 13.8 [12.6-14.4] s; 34% vs. 13%, respectively, p<0.05 for all). When compared, the PT and complication rate in group 1 with the control group C min,ss of rivaroxaban were practically the same (p>0.05 for all). Conclusions In patients ≥80 years with NAF, the use of rivaroxaban in combination with verapamil may not be safe and can lead to CRNM bleeding.

Incidence of Direct Oral Anticoagulant Prescriptions in Kidney Transplant Recipients in Ontario, Canada

BACKGROUND

Kidney transplant recipients (KTRs) are routinely excluded from direct oral anticoagulant (DOAC) trials. Given the lack of safety and efficacy data in this population, we examined real-world prescribing practices of DOACs in KTRs.

METHODS

We conducted a retrospective cohort study using linked administrative data sets in Ontario, Canada. All adult KTRs (n = 5580) from June 23, 2009, to March 31, 2017, were included. The primary outcomes were the first prescription for a DOAC or warfarin. Patients were censored on graft failure, death, or end of follow-up.

RESULTS

The mean age was 55 (SD, 14) years; 63% were male, and 65% had received a deceased donor kidney. Over a median follow-up of 5.5 and 4.7 years, 224 KTRs (4.0%) and 824 KTRs (14.8%) were prescribed DOACs and warfarin, respectively. The rates of DOAC and warfarin prescriptions were 8.1 and 32.6 per 1000 person-years, respectively. Older age, receipt of a kidney transplant in more recent years, and higher baseline estimated glomerular filtration rate were associated with DOAC prescription compared with warfarin. Patients with multiple comorbidities and a history of deep venous thromboembolism had a lower risk of DOAC prescription compared with warfarin. When examined by era, the incidence rate of both DOAC and warfarin prescriptions increased significantly over time.

CONCLUSIONS

Despite limited safety and efficacy data, DOACs are prescribed to KTRs. However, warfarin still remains more commonly prescribed in this selected patient population. Anticoagulant prescriptions overall are on the rise in KTRs. Further study is needed to determine the safety and efficacy of DOACs in KTRs.

A Real-World Observational Study of Hospitalization and Health Care Costs Among Nonvalvular Atrial Fibrillation Patients Prescribed Oral Anticoagulants in the U.S. Medicare Population

This article has been corrected. Please see J Manag Care Spec Pharm, 2020;26(5):682 BACKGROUND: Clinical trials have shown that direct oral anticoagulants (DOACs)-including dabigatran, rivaroxaban, apixaban, and edoxaban-are at least as effective and safe as warfarin for the risk of stroke/systemic embolism (SE) and major bleeding (MB) in patients with atrial fibrillation (AF). However, few studies have compared oral anticoagulants (OACs) among elderly patients.

OBJECTIVE

To compare hospitalization risks (all-cause, stroke/SE-related, and MB-related) and associated health care costs among elderly nonvalvular AF (NVAF) patients in the Medicare population who initiated warfarin, dabigatran, rivaroxaban, or apixaban.

METHODS

Patients (aged ≥ 65 years) initiating warfarin or DOACs (apixaban, rivaroxaban, and dabigatran) were selected from the Centers for Medicare & Medicaid Services database from January 1, 2013, to December 31, 2014. Patients initiating each OAC were matched 1:1 to apixaban patients using propensity score matching to balance demographic and clinical characteristics. Cox proportional hazards models were used to estimate the risk of hospitalization of each OAC versus apixaban. Generalized linear models and two-part models with bootstrapping were used to compare all-cause health care costs and stroke/SE- and MB-related medical costs between matched cohorts.

RESULTS

Of the 264,479 eligible patients, 77,480 warfarin-apixaban, 41,580 dabigatran-apixaban, and 77,640 rivaroxaban-apixaban patients were matched. The OACs were associated with a significantly higher risk of all-cause hospitalization compared with apixaban (warfarin: HR = 1.27, 95% CI = 1.23-1.31, P < 0.001; dabigatran: HR = 1.13, 95% CI = 1.08-1.18, P < 0.001; and rivaroxaban: HR = 1.22, 95% CI = 1.18-1.26, P < 0.001) and were associated with a significantly higher risk of hospitalization due to stroke/SE (warfarin: HR = 2.18, 95% CI = 1.80-2.64, P < 0.001; dabigatran: HR = 1.45, 95% CI = 1.12-1.88, P = 0.006; and rivaroxaban: HR = 1.40, 95% CI = 1.14-1.71, P = 0.001). Also, the OACs were associated with significantly higher risk of hospitalization due to MB-related conditions compared with apixaban (warfarin: HR = 1.76, 95% CI = 1.59-1.95, P < 0.001; dabigatran: HR = 1.44, 95% CI = 1.23-1.68, P < 0.001; and rivaroxaban: HR = 1.89, 95% CI = 1.71-2.09, P < 0.001). Compared with apixaban, warfarin ($3,577 vs. $3,183, P < 0.001); dabigatran ($3,217 vs. $3,060, P < 0.001); and rivaroxaban ($3,878 vs. $3,180, P < 0.001) had significantly higher all-cause total health care costs per patient per month. Patients initiating the OACs had significantly higher MB-related medical costs compared with apixaban: warfarin ($472 vs. $269; P < 0.001); dabigatran ($364 vs. $245, P < 0.001); and rivaroxaban ($493 vs. $270, P < 0.001). Warfarin was also associated with higher stroke/SE-related medical costs compared with apixaban ($124 vs. $62, P < 0.001).

CONCLUSIONS

This real-world study showed that among elderly NVAF patients in the Medicare population, apixaban was associated with significantly lower risks of all-cause, stroke/SE-related, and MB-related hospitalizations compared with warfarin, dabigatran, and rivaroxaban. Accordingly, apixaban showed significantly lower all-cause health care costs and MB-related medical costs.

DISCLOSURES

This study was funded by Bristol Myers Squibb and Pfizer. Amin is an employee of the University of California, Irvine, and was a paid consultant to Bristol Myers Squibb in connection with this study and the development of this manuscript. He has served as a consultant and/or speaker for Bristol Myers Squibb, Pfizer, and Boehringer Ingelheim. Keshishian and Zhang are employees of STATinMED Research, a paid consultant to Pfizer and Bristol Myers Squibb in connection with this study and the development of this manuscript. Trocio, Dina, Mardekian, and Liu are employees of Pfizer, with ownership of stocks in Pfizer. Le, Rosenblatt, Nadkarni, and Vo are employees of Bristol Myers Squibb. Rosenblatt and Vo have ownership of stocks in Bristol Myers Squibb. Baser has no conflicts to disclose.

Motivational Interviewing to Support Oral AntiCoagulation adherence in patients with non-valvular Atrial Fibrillation (MISOAC-AF): a randomized clinical trial

AIMS

We aimed to assess the impact of an educational, motivational intervention on the adherence to oral anticoagulation (OAC) in patients with non-valvular atrial fibrillation (AF).

METHODS AND RESULTS

Hospitalized patients with non-valvular AF who received OAC were randomly assigned to usual medical care or a proactive intervention, comprising motivational interviewing, and tailored counselling on medication adherence. The primary study outcome was adherence to OAC at 1 year, which was evaluated according to proportion of days covered (PDC) by OAC regimens and was assessed through nationwide registers of prescription claims. Secondary outcomes included the rate of persistence to OAC, gaps in treatment, and clinical events. A total of 1009 patients were randomized, 500 in the intervention group and 509 in the control group. At 1-year follow-up, 77.2% (386/500) of patients in the intervention group were adherent (PDC > 80%), compared with 55% (280/509) in the control group [adjusted odds ratio (aOR) 2.84, 95% confidence interval (CI) 2.14-3.75; P < 0.001]. Mean PDC ± standard deviation was 0.85 ± 0.26 and 0.75 ± 0.31, respectively (P < 0.001). Patients that received the intervention were more likely to persist in their OAC therapy at 1 year (aOR 2.42, 95% CI 1.71-3.41; P < 0.001). Usual medical care was associated with more major (≥3 months) treatment gaps (aOR 2.39, 95% CI 1.76-3.26; P < 0.001). Clinical events over a median follow-up period of 2 years did not differ among treatment groups.

CONCLUSION

In patients receiving OAC therapy for non-valvular AF, a multilevel motivational intervention significantly improved medication adherence and rate of therapy persistence, and reduced major gaps in treatment. No significant impact on clinical outcomes was observed.

TRIAL REGISTRATION NUMBER

NCT02941978.

A UHPLC-MS/MS method to simultaneously quantify apixaban, edoxaban and rivaroxaban in human plasma and breast milk: For emerging lactation studies

Clinical studies are needed to clarify the use of direct oral anticoagulants (DOACs) in breastfeeding women. To support emerging clinical studies on investigating DOAC's transfer into breast milk, an ultra-high-performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for quantifying three DOACs - apixaban, edoxaban and rivaroxaban in human plasma and breast milk. Protein precipitation with methanol was performed for sample preparation. Chromatographic analysis was performed using a C18 column. The MS detection was performed in MRM mode. The method was validated in accordance with the European Guideline (EMA). The calibration range was 5-500 ng/mL in plasma and 5-250 ng/mL in breast milk. The within-batch and between-batch variability remained <9%. Recoveries ranged from 106.13% to 109.05% in plasma and from 93.40% to 107.91% in breast milk. The lot-to-lot matrix variability was within ±15% among a range of samples originating from many different subjects. All analytes were stable when stored for 24 h at room temperature, 7 days at 2-8 °C, and at least 5 weeks at -20 °C in both plasma and breast milk. The developed method fulfilled the EMA bioanalytical method validation guideline and was shown to be simple, fast, accurate and will now be used in a clinical trial evaluating the transfer of apixaban and rivaroxaban into human breast milk.

Persistence of oral anticoagulant treatment for atrial fibrillation in the Netherlands: A surveillance study

BACKGROUND

In contrast to vitamin K antagonists (VKA), direct oral anticoagulants (DOAC's) are not strictly monitored and dose titrated by anticoagulation clinics in the Netherlands. This may affect drug persistence of atrial fibrillation (AF) patients, whom often require lifelong treatment.

OBJECTIVES

To assess persistence of DOACs and of VKAs in patients with AF.

METHODS

Dispensing data from the Dutch Foundation of Pharmaceutical Statistics were used to monitor persistence of AF patients to DOAC from 1 January 2012-1 April 2016. In addition, we estimated the persistence of AF patients to VKA between 1 January 2004 and 1 January 2012 in data from the Anticoagulation Clinic Leiden. Non-persistence was defined as the cumulative incidence of patients who completely stopped DOAC, switched to another oral anticoagulant or stopped their VKA.

RESULTS

DOAC users (n = 77 333) were younger than VKA users (n = 10 079; 70 vs 73 years). Non-Persistence to DOAC (ie stopping with any oral anticoagulant) was 34% at 1 and 64% at 4 years, compared to 22% at one and 36% at 4 years for VKA. Approximately a Twenty-five percent of those who had stopped their initial DOAC switched to another anticoagulant (VKA or another DOAC). Multivariable analyses revealed that young age, female sex, no concomitant drug use and non-adherence were predictors for non-persistence of DOAC.

CONCLUSIONS

Persistence to DOAC was low and in line with other observational studies, and higher for VKA. Our results show a clear correlation between age <60 years and worse persistence, as well as with female and non-adherence to DOAC.

[Anticoagulant activity of direct factor Xa inhibitors as a tool to ensure the effectiveness and safety of drugs intake]

The thematic review presents modern solutions using oral anticoagulants with a focus on direct coagulation factor X inhibitors. It contains information about the pharmacodynamics and pharmacokinetics of apixaban and rivaroxaban against the background of different drug intake regimens - twice and once per day. There are shown studies of concentration dynamics and the corresponding functional response, measured using the integral method - the thrombin generation test, which is widely used in scientific research to describe hemostatic processes based on an objective quantitative assessment of the thrombin formation - a key coagulation cascade serine protease. The logical relationship between the pharmacodynamics of anticoagulant action and the clinical presentation of the effectiveness and safety of drugs is traced. The review provides links to actual literature and current clinical guidelines.

Idarucizumab for Reversal of Dabigatran in Early/Emergency Surgeries: A Case Series

BACKGROUND

Idarucizumab is a humanized, monoclonal antibody fragment used specifically to reverse the anticoagulant effects of dabigatran.

CASE REPORTS

We discuss 4 cases of patients who were treated with idarucizumab to reverse dabigatran before early/emergency surgery. Two of the patients had subdural hematomas, 1 had a splenic laceration, and 1 had Fournier gangrene. All patients received 5 g of idarucizumab before surgery. Intraoperative blood loss in all patients was normal, no adverse events were reported, and the patients recovered normally. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The case reports presented provide detailed, practical, real-world experience beyond that reported in other case reports and the Reversal Effects of Idarucizumab on Active Dabigatran study. This can help guide clinicians on how idarucizumab can reverse the anticoagulant effect of dabigatran in emergency situations, including patients with subdural hematoma. Our experience suggests that idarucizumab may be a safe and effective antidote to the effects of dabigatran in real-life bleeding situations involving early or emergency surgeries.

Effect of novel oral anticoagulants on Hospital Anxiety and Depression Scale scores

BACKGROUND

The negative impact of atrial fibrillation (AF) on health-related quality of life has been extensively documented. The aim of this study was to compare the Hospital Anxiety and Depression Scale (HADS) scores of patients with non-valvular AF during warfarin administration and after switching to novel oral anticoagulants (NOACs).

METHODS

The study comprised 100 consecutive patients on warfarin treatment between July 2018 and January 2019 for whom a transition to NOACs was planned. All patients completed the HADS at the start of the study and at least 3 months after that date.

RESULTS

The mean value of HADS-A (5.9 ± 2.1 vs. 4.4 ± 1.6, p < 0.001) and HADS-D (4.4 ± 1.7 vs. 3.7 ± 1.4, p < 0.001) scores was significantly higher in patients when they used warfarin than when they switched to NOACs. Analysis revealed that there was a significant correlation between HADS-A and HADS-D scores with age and history of bleeding (p < 0.001). The highest scores were found for patients with a history of bleeding and age ≥75 years (p < 0.001).

CONCLUSION

Our study demonstrates that patients with nonvalvular AF under treatment with NOACs had lower HADS-A and HADS-D scores compared with patients on warfarin treatment. These findings suggest that NOACs may increase the quality of life and decrease morbidity and mortality by reducing anxiety and depression.

Efficacy and safety of left atrial appendage closure in non-valvular atrial fibrillation in patients over 75 years

Percutaneous left atrial appendage closure (LAAC) may decrease risks of stroke and bleeding in elderly patients with non-valvular atrial fibrillation (NVAF), but it is still lacking of evidence. The present study aimed at evaluating the efficacy and safety of LAAC in patients with NVAF over 75 years. 351 patients with NVAF who underwent LAAC were retrospectively analyzed on the LAAC procedure characteristics and the clinical follow-up according to age (age ≥ 75 years or < 75 years). Out of the 351 patients, LAA were successfully closed in 347 patients (98.9%), including 341 with Watchman (WM) device and 6 with Amplatzer cardiac plug (ACP) device because of the WM device-incompatible anatomy. There were no significant differences in total LAAC success rate and procedure-related major complications within 7 days between the groups aged ≥ 75 years and aged < 75 years. After a nearly 2-year follow-up, there was an increased trend of major bleedings and all bleedings in the group aged ≥ 75 years, but there were no significant differences between both groups in all-cause death, cardiovascular death, stroke/TIA/system embolism, device thrombus and device gap (> 5 mm). Kaplan-Meier analysis revealed that the relative risk of annual thromboembolic events between the observed values and the expected ones based on CHA₂DS₂-VASc score in the group aged ≥ 75 years decreased more obviously (61.9% vs. 54.3%); however, the relative risk of bleedings between the observed values and the expected ones based on HAS-BLED score in the younger group aged < 75 years decreased more significantly (59.6% vs. 29.2%). LAAC in patients with advanced age (age ≥ 75 years), has the same level of efficacy, safety and feasibility as in the younger patients aged < 75 years. Thus, LAAC may be an ideal choice to prevent stroke in NVAF patients with advanced age.

Quality of oral anticoagulation with vitamin K antagonists in 'real-world' patients with atrial fibrillation: a report from the prospective multicentre FANTASIIA registry

Aims

The efficacy and safety of oral anticoagulation (OAC) using the vitamin K antagonists (VKA) are closely associated with the quality of anticoagulation, reflected by time in therapeutic range (TTR). The SAMe-TT2R2 is a risk score developed to predict the quality of anticoagulation control among VKA users. To analyse the quality of anticoagulation and its clinical determinants based on different methods in a prospective cohort of atrial fibrillation patients on VKA treatment participating in the multicentre Spanish observational registry FANTASIIA.

Methods and results

Estimated TTR was calculated from Rosendaal, direct method, international normalized ratio variability, and NICE criteria. Time in therapeutic range values were compared for those patients with a SAMe-TT2R2 score 0-2 and >2. One thousand four hundred and seventy patients were analysed (56.4% male, mean age 74.1 ± 9.5 years). Mean TTR was 61.5 ± 25.1 with Rosendaal and 64.7 ± 24.2 with direct method. There was a high correlation between both methods (ρ = 0.805). The prevalence of poor anticoagulation control was 55%. Diabetes mellitus [odds ratio (OR) 1.38; P = 0.008], peripheral artery disease (PAD, OR 1.62; P = 0.048), and HAS-BLED (OR 1.13; P = 0.022) were independently associated with TTR < 70%. SAMe-TT2R2 score 0-2 had a higher mean TTR than patients with SAMe-TT2R2 >2 (P = 0.044), with a specificity of > 90% for predicting TTR < 70%. Patients with TTR < 70% had higher risk of events (21.7 vs. 16.8%; P = 0.021).

Conclusion

In a multicentre prospective registry, 55% of AF patients had poor anticoagulation control with diabetes mellitus, PAD, and HAS-BLED being independently associated with TTR < 70%. A high SAMe-TT2R2 scores had a high specificity for predicting a TTR < 70% as an indicator of poor quality anticoagulation.

Quality of INR control and switching to non-Vitamin K oral anticoagulants between women and men with atrial fibrillation treated with Vitamin K Antagonists in Spain. A population-based, real-world study

BACKGROUND

Worldwide, there is growing evidence that quality of international normalized ratio (INR) control in atrial fibrillation patients treated with Vitamin K Antagonists (VKA) is suboptimal. However, sex disparities in population-based real-world settings have been scarcely studied, as well as patterns of switching to second-line Non-VKA oral anticoagulants (NOAC). We aimed to assess the quality of INR control in atrial fibrillation patients treated with VKA in the region of Valencia, Spain, for the whole population and differencing by sex, and to identify factors associated with poor control. We also quantified switching to Non-VKA oral anticoagulants (NOAC) and we identified factors associated to switching.

METHODS

This is a cross-sectional, population-based study. Information was obtained through linking different regional electronic databases. Outcome measures were Time in Therapeutic Range (TTR) and percentage of INR determinations in range (PINRR) in 2015, and percentage of switching to NOAC in 2016, for the whole population and stratified by sex.

RESULTS

We included 22,629 patients, 50.4% were women. Mean TTR was 62.3% for women and 63.7% for men, and PINNR was 58.3% for women and 60.1% for men (p<0.001). Considering the TTR<65% threshold, 53% of women and 49.3% of men had poor anticoagulation control (p<0.001). Women, long-term users antiplatelet users, and patients with comorbidities, visits to Emergency Department and use of alcohol were more likely to present poor INR control. 5.4% of poorly controlled patients during 2015 switched to a NOAC throughout 2016, with no sex differences.

CONCLUSION

The quality of INR control of all AF patients treated with VKA in 2015 in our Southern European region was suboptimal, and women were at a higher risk of poor INR control. This reflects sex disparities in care, and programs for improving the quality of oral anticoagulation should incorporate the gender perspective. Clinical inertia may be lying behind the observed low rates of switching in patient with poor INR control.

Quantification of Apixaban, Dabigatran, Edoxaban, and Rivaroxaban in Human Serum by UHPLC-MS/MS-Method Development, Validation, and Application

BACKGROUND

Direct oral anticoagulants (DOACs) are prescribed for anticoagulation in patients with atrial fibrillation and venous thromboembolic disease. Fixed doses are recommended, but measuring their serum drug concentrations as a basis for dose adjustments may be useful in some clinical settings.

METHODS

An ultra-high-performance liquid chromatography-tandem mass spectrometry method for the analysis of the DOACs apixaban, dabigatran, edoxaban, and rivaroxaban in human serum was developed and validated. A 100-µL serum sample was handled using a pipetting robot. Protein precipitation was performed with 375 µL of 1% formic acid in acetonitrile (vol/vol), and phospholipid removal was performed using a Waters Ostro 96-well plate. The injection volume was 1 µL, and run time was 3.0 minutes.

RESULTS

The calibration range was 5-800 nmol/L. The between-day precision relative SDs were in the range of 3.3%-10%. Recoveries ranged from 85% to 105%, and matrix effects from 88% to 102%, when corrected with internal standard. Edoxaban was, in contrast to the other DOACs, unstable when stored for more than 6 hours at 30°C. The suitability of the method was demonstrated by analyzing routine samples from 345 patients undergoing anticoagulation treatment.

CONCLUSIONS

The developed method fulfilled the set validation criteria, and its suitability was demonstrated in a routine setting. The instability of edoxaban may complicate the transport of routine samples to the laboratory.

Outcomes After Use of Standard- and Low-Dose Non-Vitamin K Oral Anticoagulants in Asian Patients With Atrial Fibrillation

Background and Purpose- Limited data are available describing the relative effectiveness, safety, and optimal dosing of non-vitamin K antagonist oral anticoagulants (NOACs) for treatment of nonvalvular atrial fibrillation in East Asian patients. We tried to compare effectiveness and safety outcomes of standard- and low-dose NOACs and warfarin in this population. Methods- Using nationwide administrative claims-based datasets from the Korean National Health Insurance Service Database (July 1, 2015, to December 31, 2016), this study comprised 56 504 anticoagulation-naive nonvalvular atrial fibrillation patients with high thromboembolic risk (CHA2DS2-VASc score, ≥2) treated with oral anticoagulants. Main study outcomes included thromboembolic events (ischemic stroke or systemic embolism), major bleeding, and mortality. Results- Among the study patients, 10 409 (18.4%) received warfarin and 46 095 (81.6%) were treated with NOACs: dabigatran (n=12 593; 22.3%), rivaroxaban (n=21 000; 37.2%), and apixaban (n=12 502; 22.1%). Low-dose NOAC (75.1% dabigatran, 59.7% rivaroxaban, and 62.7% apixaban) was more frequently used than standard-dose NOAC. During median follow-up of 15.0 months, each NOAC was associated with significantly lower risk of thromboembolic events (hazard ratio [HR], 0.76; 95% CI, 0.75-0.81 for dabigatran; HR, 0.74; 95% CI, 0.65-0.83 for rivaroxaban; and HR, 0.68; 95% CI, 0.59-0.78 for apixaban). Regarding safety outcomes, dabigatran (HR, 0.81; CI, 0.69-0.95) and apixaban (HR, 0.67; CI, 0.56-0.79) were associated with lower risk of major bleeding but not with rivaroxaban (HR, 0.96; CI, 0.84-1.11). Among adults <75 years of age without chronic kidney disease, use of low-dose apixaban did not demonstrate clinical benefit over warfarin with respect to thromboembolic events (HR, 0.99; CI, 0.76-1.28) and mortality (HR, 0.85; CI, 0.62-1.16). Conclusions- In this cohort of East Asian patients with nonvalvular atrial fibrillation, NOACs were associated with better effectiveness and safety outcomes versus warfarin. Lower NOAC doses were more often used, but an unjustified underdosing of apixaban seems to result in lower clinical benefit.

A Real-World Observational Study of Hospitalization and Health Care Costs Among Nonvalvular Atrial Fibrillation Patients Prescribed Oral Anticoagulants in the U.S. Medicare Population

BACKGROUND

Clinical trials have shown that direct oral anticoagulants (DOACs)-including dabigatran, rivaroxaban, apixaban, and edoxaban-are at least as effective and safe as warfarin for the risk of stroke/systemic embolism (SE) and major bleeding (MB) in patients with atrial fibrillation (AF). However, few studies have compared oral anticoagulants (OACs) among elderly patients.

OBJECTIVE

To compare hospitalization risks (all-cause, stroke/SE-related, and MB-related) and associated health care costs among elderly nonvalvular AF (NVAF) patients in the Medicare population who initiated warfarin, dabigatran, rivaroxaban, or apixaban.

METHODS

Patients (aged ≥ 65 years) initiating warfarin or DOACs (apixaban, rivaroxaban, and dabigatran) were selected from the Centers for Medicare & Medicaid Services database from January 1, 2013, to December 31, 2014. Patients initiating each OAC were matched 1:1 to apixaban patients using propensity score matching to balance demographic and clinical characteristics. Cox proportional hazards models were used to estimate the risk of hospitalization of each OAC versus apixaban. Generalized linear models and two-part models with bootstrapping were used to compare all-cause health care costs and stroke/SE- and MB-related medical costs between matched cohorts.

RESULTS

Of the 186,132 eligible patients, 41,606 warfarin-apixaban, 30,836 dabigatran-apixaban, and 41,608 rivaroxaban-apixaban pairs were matched. The OACs were associated with a significantly higher risk of all-cause hospitalization compared with apixaban (warfarin: HR = 1.33, 95% CI = 1.27-1.38, P < 0.001; dabigatran: HR = 1.17, 95% CI = 1.11-1.23, P < 0.001; and rivaroxaban: HR = 1.27, 95% CI = 1.22-1.32, P < 0.001) and were associated with a significantly higher risk of hospitalization due to stroke/SE (warfarin: HR = 2.51, 95% CI = 1.92-3.29, P < 0.001; dabigatran: HR = 2.24, 95% CI = 1.60-3.13, P < 0.001; and rivaroxaban: HR = 1.74, 95% CI = 1.31-2.30, P < 0.001). Also, the OACs were associated with significantly higher risk of hospitalization due to MB-related conditions compared with apixaban (warfarin: HR = 1.96, 95% CI = 1.71-2.23, P < 0.001; dabigatran: HR = 1.48; 95% CI = 1.25-1.76, P < 0.001; and rivaroxaban: HR = 2.17, 95% CI = 1.91-2.48, P < 0.001). Compared with apixaban, warfarin ($3,747 vs. $3,061, P < 0.001); dabigatran ($3,230 vs. $2,951, P < 0.001); and rivaroxaban ($3,950 vs. $3,060, P < 0.001) had significantly higher all-cause total health care costs per patient per month. Patients initiating the OACs also had significantly higher stroke/SE- and MB-related medical costs compared with apixaban: warfarin (stroke/SE = $135 vs. $60, P = 0.001; MB = $537 vs. $286, P < 0.001); dabigatran (stroke/SE = $94 vs. $62, P = 0.045; MB = $373 vs. $277, P = 0.010); and rivaroxaban (stroke/SE = $91 vs. $60, P = 0.008; MB = $524 vs. $287, P < 0.001).

CONCLUSIONS

This real-world study showed that among elderly NVAF patients in the Medicare population, apixaban was associated with significantly lower risks of all-cause, stroke/SE-related, and MB-related hospitalizations compared with warfarin, dabigatran, and rivaroxaban. Accordingly, apixaban showed significantly lower all-cause health care costs and stroke/SE- and MB-related medical costs.

DISCLOSURES

This study was funded by Bristol-Myers Squibb and Pfizer. Amin is an employee of the University of California, Irvine, and was a paid consultant to Bristol-Myers Squibb in connection with this study and the development of this manuscript. Keshishian and Zhang are employees of STATinMED Research, a paid consultant to Pfizer and Bristol-Myers Squibb in connection with this study and the development of this manuscript. Trocio, Dina, Mardekian, and Liu are employees of Pfizer, with ownership of stocks in Pfizer. Le, Rosenblatt, Nadkarni, and Vo are employees of Bristol-Myers Squibb. Rosenblatt and Vo have ownership of stocks in Bristol-Myers Squibb. Baser has no conflicts to disclose.

Pre-clinical pharmacodynamic study of a novel oral factor Xa inhibitor zifaxaban

Zifaxaban is an orally active, direct Factor Xa (FXa) inhibitor that is in development for the prevention and treatment of arterial and venous thrombosis. This study was conducted to investigate the biochemical and pharmacological activity of zifaxaban. In vitro activity was evaluated by enzyme, platelet aggregation, and clotting assays. In vivo effects were examined in venous thrombosis, arteriovenous-shunt thrombosis, carotid thrombosis, and bleeding models in rats. Zifaxaban competitively inhibits human FXa (IC₅₀ = 11.1 nM) with > 10,000-fold greater selectivity than other serine proteases. It did not impair platelet aggregation induced by collagen, adenosine diphosphate (ADP) or arachidonic acid. It significantly prolonged clotting time, prothrombin time (PT), and activated partial thromboplastin time (APTT) in the plasma of humans, rabbits, and rats, with a relatively weak effect on thrombin time (TT). In venous thrombosis models in rats, zifaxaban strongly suppressed thrombus formation with ED₅₀ values of 3.09 mg/kg, and its best efficacy time occurred at 2 h after administration. In arteriovenous-shunt thrombosis and carotid thrombosis models in rats, it inhibited thrombus formation in a dose-dependent manner. And in the rat tail bleeding assay, it showed a trend of less bleeding than rivaroxaban at doses that achieved the same antithrombotic effect. In conclusion, zifaxaban is a selective and direct FXa inhibitor and a promising oral anticoagulant for the prophylaxis and treatment of thromboembolic diseases.

Development and validation of a questionnaire to self-assess patient knowledge of direct oral anticoagulants (KODOA-test)

Objective

Few studies have examined associations between patient knowledge of direct oral anticoagulants (DOAC) and clinical outcomes, mostly because of the lack of validated questionnaires for assessing knowledge. The aim of this study was to develop and validate a questionnaire to self-assess knowledge of DOAC.

Methods

Twelve anticoagulation experts participated in the questionnaire development process to ensure content validity. The Knowledge Of Direct Oral Anticoagulants (KODOA)-test was submitted to patients on DOAC and to pharmacists to assess construct validity. Responsiveness was evaluated after educational counseling. Test-retest reliability was assessed to ensure stability over time, and Cronbach's α was calculated for internal reliability. Index of difficulty and item discrimination (D-value) were calculated to assess the performance of single items.

Results

The KODOA-test contains 15 items with multiple-choice answers. Each correct answer scores 1 point (max. score of 15). The KODOA-test was administered to 32 patients on DOAC and 28 pharmacists. Pharmacists scored significantly higher than patients at baseline (median score 13.3 vs 10.0; p<0.001), supporting construct validity. Patient scores increased significantly after educational counseling (median score 11 [interquartile range 2] vs 14 [interquartile range 3]; p<0.001). Test-retest and Cronbach's α were acceptable with a Pearson's correlation of 0.8 and an α of 0.67. The index of difficulty for most items was satisfactory (0.38-0.72) and the mean D-value was 42.5%.

Conclusion

The KODOA-test is a brief, valid, and reliable knowledge self-assessment questionnaire that may be used in clinical trials to investigate associations between knowledge increase and patient-related outcomes.

Strategies for improving dabigatran adherence for stroke prevention in patients with non-valvular atrial fibrillation: education and drug intake reminders (FACILITA study)

Objective To assess the efficacy of a mixed intervention, educational, and reminder calendar of the intake, as a strategy to improve therapeutic adherence with dabigatran in patients with non-valvular atrial fibrillation (NVAF). Methods This was a prospective, longitudinal, multi-center study, carried out in 110 specialized healthcare centers in Spain. Seven hundred and twenty-six patients treated with dabigatran prescribed for stroke prevention were included. A cluster randomization was performed based on two groups: (1) Control Group (CG) as usual clinical practice, and (2) Intervention Group (IG) with a mixed strategy: (a) Healthcare education, and (b) Use of a reminder calendar for taking the anticoagulant medication. Three visits took place: baseline and follow-up at 6 and 12 months. Compliance was measured by using electronic monitors (MEMS). Average adherence percentage (%; Average AP) and daily compliance (%; Daily AP) was calculated. A patient was considered adherent when AP was 80-100%. Results Six hundred and twenty-five patients completed the study (315 in the IG and 310 in the CG). Daily AP was 91.97% at 6 months and 91.05% after 12 months in the IG and 82.26% and 82.63% in the CG. Average adherence was 90.79% and 89.20% in the IG and 64.51% and 63.22% in the CG at 6 and 12 months, respectively. Significant differences were observed in the Daily AP and Average AP, with higher percentages in the IG. In the non-adherents group, the number of concomitant drugs, baseline, and 6 months SBP values, 6 and 12 months DBP values, and weight, total cholesterol, and LDL cholesterol were significantly higher. The number needed to treat (NNT) was 3.84 patients to prevent one non-adherence. Conclusions A mixed intervention, consisting of patient education and a simple calendar reminder of drug intake, is an effective strategy to improve dabigatran therapeutic adherence in patients with NVAF. The percentage of adherence with dabigatran was high.

Evaluating the Usability and Usefulness of a Mobile App for Atrial Fibrillation Using Qualitative Methods: Exploratory Pilot Study

BACKGROUND

Atrial fibrillation (AFib) is the most common form of heart arrhythmia and a potent risk factor for stroke. Nonvitamin K antagonist oral anticoagulants (NOACs) are routinely prescribed to manage AFib stroke risk; however, nonadherence to treatment is a concern. Additional tools that support self-care and medication adherence may benefit patients with AFib.

OBJECTIVE

The aim of this study was to evaluate the perceived usability and usefulness of a mobile app designed to support self-care and treatment adherence for AFib patients who are prescribed NOACs.

METHODS

A mobile app to support AFib patients was previously developed based on early stage interview and usability test data from clinicians and patients. An exploratory pilot study consisting of naturalistic app use, surveys, and semistructured interviews was then conducted to examine patients' perceptions and everyday use of the app.

RESULTS

A total of 12 individuals with an existing diagnosis of nonvalvular AFib completed the 4-week study. The average age of participants was 59 years. All participants somewhat or strongly agreed that the app was easy to use, and 92% (11/12) reported being satisfied or very satisfied with the app. Participant feedback identified changes that may improve app usability and usefulness for patients with AFib. Areas of usability improvement were organized by three themes: app navigation, clarity of app instructions and design intent, and software bugs. Perceptions of app usefulness were grouped by three key variables: core needs of the patient segment, patient workflow while managing AFib, and the app's ability to support the patient's evolving needs.

CONCLUSIONS

The results of this study suggest that mobile tools that target self-care and treatment adherence may be helpful to AFib patients, particularly those who are newly diagnosed. Additionally, participant feedback provided insight into the varied needs and health experiences of AFib patients, which may improve the design and targeting of the intervention. Pilot studies that qualitatively examine patient perceptions of usability and usefulness are a valuable and often underutilized method for assessing the real-world acceptability of an intervention. Additional research evaluating the AFib Connect mobile app over a longer period, and including a larger, more diverse sample of AFib patients, will be helpful for understanding whether the app is perceived more broadly to be useful and effective in supporting patient self-care and medication adherence.

Real-world comparison of all-cause hospitalizations, hospitalizations due to stroke and major bleeding, and costs for non-valvular atrial fibrillation patients prescribed oral anticoagulants in a US health plan

AIMS

To compare the risk of all-cause hospitalization and hospitalizations due to stroke/systemic embolism (SE) and major bleeding, as well as associated healthcare costs for non-valvular atrial fibrillation (NVAF) patients initiating apixaban, dabigatran, rivaroxaban, or warfarin.

MATERIALS AND METHODS

NVAF patients initiating apixaban, dabigatran, rivaroxaban, or warfarin were selected from the OptumInsight Research Database from January 1, 2013-September 30, 2015. Propensity score matching (PSM) was performed between apixaban and each oral anticoagulant. Cox models were used to estimate the risk of stroke/SE and major bleeding. Generalized linear and 2-part models were used to compare healthcare costs.

RESULTS

Of the 47,634 eligible patients, 8,328 warfarin-apixaban pairs, 3,557 dabigatran-apixaban pairs, and 8,440 rivaroxaban-apixaban pairs were matched. Compared to apixaban, warfarin patients were associated with a significantly higher risk of all-cause (hazard ratio [HR] = 1.30; 95% confidence interval [CI] = 1.21-1.40) as well as stroke/SE-related (HR = 1.60; 95% CI = 1.23-2.07) and major bleeding-related (HR = 1.95; 95% CI = 1.60-2.39) hospitalization; rivaroxaban patients were associated with a higher risk of all-cause (HR = 1.15; 95% CI = 1.07-1.24) and major bleeding-related hospitalization (HR = 1.71; 95% CI = 1.39-2.10); and dabigatran patients were associated with a higher risk of major bleeding hospitalization (HR = 1.46, 95% CI = 1.02-2.10). Warfarin patients had significantly higher major bleeding-related and total all-cause healthcare costs compared to apixaban patients. Rivaroxaban patients had significantly higher major bleeding-related costs compared to apixaban patients. No significant results were found for the remaining comparisons.

LIMITATIONS

No causal relationships can be concluded, and unobserved confounders may exist in this retrospective database analysis.

CONCLUSIONS

This study demonstrated a significantly higher risk of hospitalization (all-cause, stroke/SE, and major bleeding) associated with warfarin, a significantly higher risk of major bleeding hospitalization associated with dabigatran or rivaroxaban, and a significantly higher risk of all-cause hospitalization associated with rivaroxaban compared to apixaban. Lower major bleeding-related costs were observed for apixaban patients compared to warfarin and rivaroxaban patients.

Effect of Non-vitamin K Antagonist Oral Anticoagulants in Atrial Fibrillation Patients with Newly Diagnosed Cancer

BACKGROUND AND OBJECTIVES

There are limited data on the use of non-vitamin K antagonist oral anticoagulants (NOACs) in atrial fibrillation (AF) patients with cancer. We aimed to assess the efficacy and safety of NOACs in AF patients with cancer in this study.

METHODS

In 2,568 consecutive non-valvular AF patients with newly diagnosed cancer, we analyzed ischemic stroke/systemic embolism (SE), major bleeding, and all-cause death. Based on propensity score matching, 388 matched pairs were included in the NOAC and warfarin groups.

RESULTS

Patient baseline characteristics were comparable between the matched groups. During median follow-up of 1.8 years, the NOAC group had significantly lower incidences of ischemic stroke/SE (p<0.001), major bleeding (p<0.001), and all-cause death (p<0.001) than the warfarin group. Moreover, the incidence of major bleeding was significantly lower in the NOAC group than in the warfarin group with optimal international normalized ratio control (p=0.03). Especially, within 1 year after cancer diagnosis, the incidences of all clinical events were significantly lower in the NOAC group than in the warfarin group.

CONCLUSIONS

In AF patients with newly diagnosed cancer, NOACs showed lower incidences of ischemic stroke/SE, major bleeding, and all-cause death than warfarin, especially within 1 year after cancer diagnosis.

Impaired Rivaroxaban Clearance in Mild Renal Insufficiency With Verapamil Coadministration: Potential Implications for Bleeding Risk and Dose Selection

Pharmacokinetics and antithrombotic effects of the Factor Xa inhibitor rivaroxaban were studied in subjects with mild renal insufficiency concurrently taking the P-glycoprotein and moderate CYP3A inhibitor verapamil, a drug commonly administered to patients with hypertension, ischemic heart disease, or atrial fibrillation. Age-matched controls with normal renal function were studied concurrently. Subjects' overall mean age was 59 years. Mean creatinine clearance values in the 2 groups were 105 and 71 mL/min. After single 20-mg oral doses, rivaroxaban area under the curve (AUC) was increased by a factor of 1.11 (ratio of geometric means [RGM]) in mild renal insufficiency compared to controls. Verapamil coadministration independently increased AUC to the same extent in both the mild renal insufficiency and control groups (RGM, 1.39 and 1.43). Concurrent mild renal insufficiency and verapamil produced additive inhibition compared to controls without verapamil (RGM, 1.58). Prothrombin time (PT) prolongation and Factor Xa inhibition tracked plasma rivaroxaban, and were enhanced by verapamil. Concentration-response relationships for PT (linear) and Factor Xa inhibition (hyperbolic) were unaffected by renal function or verapamil. The absolute and relative increases in rivaroxaban AUC caused by verapamil in mild renal insufficiency subjects are potentially associated with an increased bleeding risk. Modification of recommended dosage may be required in this combination of circumstances to reduce risk to patients.

Safety and Efficacy of Underdosing Non-vitamin K Antagonist Oral Anticoagulants in Patients Undergoing Catheter Ablation for Atrial Fibrillation

Background:

Some patients with atrial fibrillation (AF) received underdoses of non-vitamin K antagonist oral anticoagulants (NOACs) in the real world. Underdosing is defined as administration of a dose lower than the manufacturer recommended dose.

Objectives:

To identify the efficacy and safety of underdosing NOACs as perioperative anticoagulation for atrial fibrillation ablation.

Methods:

We retrospectively analyzed patients who received rivaroxaban or dabigatran etexilate according to dosage: adjusted low dosage (reduced by disturbed renal function; n = 30), underdosage (n = 307), or standard dosage (n = 683). Non-vitamin K antagonist oral anticoagulants and dosing decisions were at the discretion of treating cardiologists.

Results:

Patients who received underdosed NOACs were older, more often female, and had lower body weight and lower renal function than those who received standard dosages. Activated clotting time at baseline in patients who received adjusted low dosage or underdosages was slightly longer than that in patients receiving standard dosages (156 ± 23, 151 ± 224, and 147 ± 24 seconds, respectively). Meaningful differences were not observed in other coagulation parameters. Adjusted low-, under-, and standard-dosing regimens did not differ in perioperative thromboembolic complications (0/30, 0.0%; 1/307, 0.3%; and 0/683, 0%, respectively) or major (0/30, 0.0%; 2/307, 0.6%; 3/683, 0.4%) and minor (1/30, 3.3%; 13/307, 4.2%; 25/683, 3.6%) bleeding episodes. When comparisons were performed for each NOAC, similar results were observed.

Conclusions:

With consideration of patient condition, age, sex, body weight, body mass index, and renal function, underdosing NOACs was effective and safe as a perioperative anticoagulation therapy for atrial fibrillation ablation. The therapeutic range of NOACs is potentially wider than manufacturer recommendations.

Novel FXa Inhibitor Identification through Integration of Ligand- and Structure-Based Approaches

Factor Xa (FXa), a vitamin K-dependent serine protease plays a pivotal role in the coagulation cascade, one of the most interesting targets for the development of new anticoagulants. In the present work, we performed a virtual screening campaign based on ligand-based shape and electrostatic similarity search and protein-ligand docking to discover novel FXa-targeted scaffolds for further development of inhibitors. From an initial set of 260,000 compounds from the NCI Open database, 30 potential FXa inhibitors were identified and selected for in vitro biological evaluation. Compound 5 (NSC635393, 4-(3-methyl-4H-1,4-benzothiazin-2-yl)-2,4-dioxo-N-phenylbutanamide) displayed an IC₅₀ value of 2.02 nM against human FXa. The identified compound may serve as starting point for the development of novel FXa inhibitors.

The Use of Electronic Personal Health Records to Improve Medication Adherence and Patient Engagement: A Randomized Study of Non-valvular Atrial Fibrillation Patients

Embolic stroke is a major complication of atrial fibrillation (AF) that frequently results in disability or death. The administration of oral anticoagulation can reduce stroke risk in AF patients; however, medication non-adherence can eliminate this benefit. To date, reported patient adherence rates to oral anticoagulation regimens vary. The objective of the current study was to examine the impact of medication-specific education delivered via a personal health record (PHR) system on medication adherence. A randomized, prospective study was conducted from February 2014 to June 2014 at Parkview Health, a not-for-profit, community-based health care clinic that serves a northeastern Indiana population of more than 820,000. AF patients receiving dabigatran (Pradaxa^®; Boehringer Ingelheim GmbH, Ingelheim am Rhein, Germany) to prevent stroke participated in this study. The study participants were predominantly Caucasian males over 65 years of age who were educated, insured, and living above the poverty level. Patients were allowed to view online, download, and transmit health information via a PHR. The intervention group received PHR training and dabigatran education via the PHR. The control group received standard care and PHR access without training. A longitudinal survey pertaining to medication knowledge, medication adherence, and patient engagement was administered at baseline and at the end of the study. Medication-dispensing data collected from pharmacy refill prescriptions were used for calculating the medication possession ratio (MPR). Ninety patients were included in this study, and were randomly assigned to either the intervention group (n = 46) or the control group (n = 44). All participants completed the baseline survey, and 95.6% of patients finished the follow-up survey. The mean score for knowledge increased significantly in the intervention group (from 3.77 to 4.23, p = 0.005), but not in the control group (from 3.70 to 3.95, p = 0.72).

The MPR was significantly higher in the intervention group (97.47% vs. 87.67%, p = 0.001). Both groups had similar levels of improvement in Patient Activation Measure scores (from 63.0 to 65.8, p = 0.078 vs. from 63.1 to 63.6, p = 0.814). Patients who used the PHR achieved greater medication knowledge, resulting in improved medication adherence. To our knowledge, no published randomized trial has reported on the use of PHRs to improve medication adherence and knowledge. This study is the first to demonstrate a positive impact on anticoagulation adherence with PHR use.

The Reversal of Direct Oral Anticoagulants in Animal Models

Several direct oral anticoagulants (DOACs), including direct thrombin and factor Xa inhibitors, have been approved as alternatives to vitamin K antagonist anticoagulants. As with any anticoagulant, DOAC use carries a risk of bleeding. In patients with major bleeding or needing urgent surgery, reversal of DOAC anticoagulation may be required, presenting a clinical challenge. The optimal strategy for DOAC reversal is being refined, and may include use of hemostatic agents such as prothrombin complex concentrates (PCCs; a source of concentrated clotting factors), or DOAC-specific antidotes (which bind their target DOAC to abrogate its activity). Though promising, most specific antidotes are still in development.Preclinical animal research is the key to establishing the efficacy and safety of potential reversal agents. Here, we summarize published preclinical animal studies on reversal of DOAC anticoagulation. These studies (n = 26) were identified via a PubMed search, and used rodent, rabbit, pig, and non-human primate models. The larger of these animals have the advantages of similar blood volume/hemodynamics to humans, and can be used to model polytrauma. We find that in addition to varied species being used, there is variability in the models and assays used between studies; we suggest that blood loss (bleeding volume) is the most clinically relevant measure of DOAC anticoagulation-related bleeding and its reversal.The studies covered indicate that both PCCs and specific reversal agents have the potential to be used as part of a clinical strategy for DOAC reversal. For the future, we advocate the development and use of standardized, clinically, and pharmacologically relevant animal models to study novel DOAC reversal strategies.