Serious Bleeding in Patients With Atrial Fibrillation Using Diltiazem With Apixaban or Rivaroxaban.

Importance: Diltiazem, a commonly prescribed ventricular rate-control medication for patients with atrial fibrillation, inhibits apixaban and rivaroxaban elimination, possibly causing overanticoagulation. Objective: To compare serious bleeding risk for new users of apixaban or rivaroxaban with atrial fibrillation treated with diltiazem or metoprolol. Design, Setting, and Participants: This retrospective cohort study included Medicare beneficiaries aged 65 years or older with atrial fibrillation who initiated apixaban or rivaroxaban use and also began treatment with diltiazem or metoprolol between January 1, 2012, and November 29, 2020. Patients were followed up to 365 days through November 30, 2020. Data were analyzed from August 2023 to February 2024. Exposures: Diltiazem and metoprolol. Main Outcomes and Measures: The primary outcome was a composite of bleeding-related hospitalization and death with recent evidence of bleeding. Secondary outcomes were ischemic stroke or systemic embolism, major ischemic or hemorrhagic events (ischemic stroke, systemic embolism, intracranial or fatal extracranial bleeding, or death with recent evidence of bleeding), and death without recent evidence of bleeding. Hazard ratios (HRs) and rate differences (RDs) were adjusted for covariate differences with overlap weighting. Results: The study included 204 155 US Medicare beneficiaries, of whom 53 275 received diltiazem and 150 880 received metoprolol. Study patients (mean [SD] age, 76.9 [7.0] years; 52.7% female) had 90 927 person-years (PY) of follow-up (median, 120 [IQR, 59-281] days). Patients receiving diltiazem treatment had increased risk for the primary outcome (RD, 10.6 [95% CI, 7.0-14.2] per 1000 PY; HR, 1.21 [95% CI, 1.13-1.29]) and its components of bleeding-related hospitalization (RD, 8.2 [95% CI, 5.1-11.4] per 1000 PY; HR, 1.22 [95% CI, 1.13-1.31]) and death with recent evidence of bleeding (RD, 2.4 [95% CI, 0.6-4.2] per 1000 PY; HR, 1.19 [95% CI, 1.05-1.34]) compared with patients receiving metoprolol. Risk for the primary outcome with initial diltiazem doses exceeding 120 mg/d (RD, 15.1 [95% CI, 10.2-20.1] per 1000 PY; HR, 1.29 [95% CI, 1.19-1.39]) was greater than that for lower doses (RD, 6.7 [95% CI, 2.0-11.4] per 1000 PY; HR, 1.13 [95% CI, 1.04-1.24]). For doses exceeding 120 mg/d, the risk of major ischemic or hemorrhagic events was increased (HR, 1.14 [95% CI, 1.02-1.27]). Neither dose group had significant changes in the risk for ischemic stroke or systemic embolism or death without recent evidence of bleeding. When patients receiving high- and low-dose diltiazem treatment were directly compared, the HR for the primary outcome was 1.14 (95% CI, 1.02-1.26). Conclusions and Relevance: In Medicare patients with atrial fibrillation receiving apixaban or rivaroxaban, diltiazem was associated with greater risk of serious bleeding than metoprolol, particularly for diltiazem doses exceeding 120 mg/d.

Temporal trends in anticoagulation use and clinical outcomes among medicare beneficiaries with non-valvular atrial fibrillation.

PURPOSE: Oral anticoagulants effectively prevent stroke/systemic embolism among patients with non-valvular atrial fibrillation but remain under-prescribed. This study evaluated temporal trends in oral anticoagulant use, the incidence of stroke/systemic embolism and major bleeding, and economic outcomes among elderly patients with non-valvular atrial fibrillation and CHA2DS2-VASc scores ≥ 2. METHODS: Retrospective analyses were conducted on Medicare claims data from January 1, 2012 through December 31, 2017. Non-valvular atrial fibrillation patients aged ≥ 65 years with CHA2DS2-VASc scores ≥ 2 were stratified by calendar year (2013-2016) of care to create calendar-year cohorts. Patient characteristics were evaluated across all cohorts during the baseline period (12 months before diagnosis). Treatment patterns and clinical and economic outcomes were evaluated during the follow-up period (from diagnosis through 12 months). RESULTS: Baseline patient characteristics remained generally similar between 2013 and 2016. Although lack of oral anticoagulant prescriptions among eligible patients remained relatively high, utilization did increase progressively (53-58%). Among treated patients, there was a progressive decrease in warfarin use (79-52%) and a progressive increase in overall direct oral anticoagulant use (21-48%). There were progressive decreases in the incidence of stroke/systemic embolism 1.9-1.4 events per 100 person years) and major bleeding (4.6-3.3 events per 100 person years) as well as all-cause costs between 2013 and 2016. CONCLUSIONS: The proportions of patients with non-valvular atrial fibrillation who were not prescribed an oral anticoagulant decreased but remained high. We observed an increase in direct oral anticoagulant use that coincided with decreased incidence of clinical outcomes as well as decreasing total healthcare costs.

Risk for Bleeding-Related Hospitalizations During Use of Amiodarone With Apixaban or Rivaroxaban in Patients With Atrial Fibrillation : A Retrospective Cohort Study.

BACKGROUND: Amiodarone, the most effective antiarrhythmic drug in atrial fibrillation, inhibits apixaban and rivaroxaban elimination, thus possibly increasing anticoagulant-related risk for bleeding. OBJECTIVE: For patients receiving apixaban or rivaroxaban, to compare risk for bleeding-related hospitalizations during treatment with amiodarone versus flecainide or sotalol, antiarrhythmic drugs that do not inhibit these anticoagulants' elimination. DESIGN: Retrospective cohort study. SETTING: U.S. Medicare beneficiaries aged 65 years or older. PATIENTS: Patients with atrial fibrillation began anticoagulant use between 1 January 2012 and 30 November 2018 and subsequently initiated treatment with study antiarrhythmic drugs. MEASUREMENTS: Time to event for bleeding-related hospitalizations (primary outcome) and ischemic stroke, systemic embolism, and death with or without recent (past 30 days) evidence of bleeding (secondary outcomes), adjusted with propensity score overlap weighting. RESULTS: There were 91 590 patients (mean age, 76.3 years; 52.5% female) initiating use of study anticoagulants and antiarrhythmic drugs, 54 977 with amiodarone and 36 613 with flecainide or sotalol. Risk for bleeding-related hospitalizations increased with amiodarone use (rate difference [RD], 17.5 events [95% CI, 12.0 to 23.0 events] per 1000 person-years; hazard ratio [HR], 1.44 [CI, 1.27 to 1.63]). Incidence of ischemic stroke or systemic embolism did not increase (RD, -2.1 events [CI, -4.7 to 0.4 events] per 1000 person-years; HR, 0.80 [CI, 0.62 to 1.03]). The risk for death with recent evidence of bleeding (RD, 9.1 events [CI, 5.8 to 12.3 events] per 1000 person-years; HR, 1.66 [CI, 1.35 to 2.03]) was greater than that for other deaths (RD, 5.6 events [CI, 0.5 to 10.6 events] per 1000 person-years; HR, 1.15 [CI, 1.00 to 1.31]) (HR comparison: P = 0.003). The increased incidence of bleeding-related hospitalizations for rivaroxaban (RD, 28.0 events [CI, 18.4 to 37.6 events] per 1000 person-years) was greater than that for apixaban (RD, 9.1 events [CI, 2.8 to 15.3 events] per 1000 person-years) (P = 0.001). LIMITATION: Possible residual confounding. CONCLUSION: In this retrospective cohort study, patients aged 65 years or older with atrial fibrillation treated with amiodarone during apixaban or rivaroxaban use had greater risk for bleeding-related hospitalizations than those treated with flecainide or sotalol. PRIMARY FUNDING SOURCE: National Heart, Lung, and Blood Institute.

Cost-effectiveness of population screening for atrial fibrillation: the STROKESTOP study.

AIMS: Previous studies on the cost-effectiveness of screening for atrial fibrillation (AF) are based on assumptions of long-term clinical effects. The STROKESTOP study, which randomised 27 975 persons aged 75/76 years into a screening invitation group and a control group, has a median follow-up time of 6.9 years. The aim of this study was to estimate the cost-effectiveness of population-based screening for AF using clinical outcomes. METHODS AND RESULTS: The analysis is based on a Markov cohort model. The prevalence of AF, the use of oral anticoagulation, clinical event data, and all-cause mortality were taken from the STROKESTOP study. The cost for clinical events, age-specific utilities, utility decrement due to stroke, and stroke death was taken from the literature. Uncertainty in the model was considered in a probabilistic sensitivity analysis. Per 1000 individuals invited to the screening, there were 77 gained life years and 65 gained quality-adjusted life years. The incremental cost was €1.77 million lower in the screening invitation group. Gained quality-adjusted life years to a lower cost means that the screening strategy was dominant. The result from 10 000 Monte Carlo simulations showed that the AF screening strategy was cost-effective in 99.2% and cost-saving in 92.7% of the simulations. In the base-case scenario, screening of 1000 individuals resulted in 10.6 [95% confidence interval (CI): -22.5 to 1.4] fewer strokes (8.4 ischaemic and 2.2 haemorrhagic strokes), 1.0 (95% CI: -1.9 to 4.1) more cases of systemic embolism, and 2.9 (95% CI: -18.2 to 13.1) fewer bleedings associated with hospitalization. CONCLUSION: Based on the STROKESTOP study, this analysis shows that a broad AF screening strategy in an elderly population is cost-effective. Efforts should be made to increase screening participation.

Delaying clinical events among patients with non-valvular atrial fibrillation treated with oral anticoagulants: Insights from the ARISTOPHANES study.

BACKGROUND: Oral anticoagulants (OACs) mitigate stroke and systemic embolism (SE) risk in non-valvular atrial fibrillation (AF) patients but can increase the risk of major bleeding (MB). This study analyzed the gains in event-free time for these outcomes among OAC treatment options represented in the ARISTOPHANES study. METHODS: This sub-analysis consisted of NVAF patients who initiated warfarin, apixaban, dabigatran, or rivaroxaban from 01JAN2013-30SEP2015, with data pooled from Medicare and 4 US commercial claims databases. Propensity score matching was conducted between non-vitamin K antagonist OAC (NOAC) and warfarin cohorts in each database and results were pooled. Laplace regression was used to evaluate the delay in time to stroke/SE and MB events between NOACs and warfarin and between NOACs after the first 12-months of follow-up. RESULTS: The population included 466,991 patients (167,413 warfarin; 108,852 apixaban; 37,724 dabigatran; and 153,002 rivaroxaban). Event-free time gain (95% confidence interval) for apixaban versus warfarin was 101 days (78- 124) for stroke/SE and 116 (103- 130) days for MB. The gain in event-free time for dabigatran versus warfarin was 45 days (3- 87) for stroke/SE and 92 (68- 116) days for MB. The gain in event-free time for rivaroxaban versus warfarin was 63 days (42- 84) for stroke/SE but event-free time decreased by 18 (-31-6) days for MB. CONCLUSIONS: Over 12 months after initiation, apixaban and dabigatran conferred progressive increases in event free time for stroke/SE and MB vs warfarin, whereas rivaroxaban conferred an increase in stroke/SE-free time but a loss in MB-free time vs warfarin.

Clinical and Economic Outcomes Among Nonvalvular Atrial Fibrillation Patients With Coronary Artery Disease and/or Peripheral Artery Disease.

To address literature gaps on treatment with real-world evidence, this study compared effectiveness, safety, and cost outcomes in NVAF patients with coronary or peripheral artery disease (CAD, PAD) prescribed apixaban versus other oral anticoagulants. NVAF patients aged ≥65 years co-diagnosed with CAD/PAD initiating warfarin, apixaban, dabigatran, or rivaroxaban were selected from the US Medicare population (January 1, 2013 to September 30, 2015). Propensity score matching was used to match apixaban versus warfarin, dabigatran, and rivaroxaban cohorts. Cox models were used to evaluate the risk of stroke/systemic embolism (SE), major bleeding (MB), all-cause mortality, and a composite of stroke/myocardial infarction/all-cause mortality. Generalized linear and two-part models were used to compare stroke/SE, MB, and all-cause costs between cohorts. A total of 33,269 warfarin-apixaban, 9,335 dabigatran-apixaban, and 33,633 rivaroxaban-apixaban pairs were identified after matching. Compared with apixaban, stroke/SE risk was higher in warfarin (hazard ratio [HR]: 1.93; 95% confidence interval [CI]: 1.61 to 2.31), dabigatran (HR: 1.69; 95% CI: 1.18 to 2.43), and rivaroxaban (HR: 1.24; 95% CI: 1.01 to 1.51) patients. MB risk was higher in warfarin (HR: 1.67; 95% CI: 1.52 to 1.83), dabigatran (HR: 1.37; 95% CI: 1.13 to 1.68), and rivaroxaban (HR: 1.87; 95% CI: 1.71 to 2.05) patients vs apixaban. Stroke/SE- and MB-related medical costs per-patient per-month were higher in warfarin, dabigatran, and rivaroxaban patients versus apixaban. Total all-cause health care costs were higher in warfarin and rivaroxaban patients compared with apixaban patients. In conclusion, compared with apixaban, patients on dabigatran, rivaroxaban, or warfarin had a higher risk of stroke/SE, MB, and event-related costs.

Biomarkers for Risk Assessment in Atrial Fibrillation.

BACKGROUND: Atrial fibrillation (AF) is associated with an increased risk of thromboembolism, which can be significantly reduced with anticoagulant treatment. Key goals in the clinical management of AF are the identification of patients at high risk for developing AF and accurate stratification of the risk of stroke and systemic embolic events (S/SEE) as well as treatment-related major bleeding. CONTENT: In this review, we describe the expanding evidence regarding the use of circulating biomarkers for predicting the risks of both incident AF and its clinically important complications of S/SEE and treatment-related major bleeding. We also review emerging biomarker-based scores for assessing these risks. SUMMARY: Patients with AF undergo progressive cardiac structural remodeling, which may precede the onset of the arrhythmia. Abnormal concentrations of circulating biomarkers reflecting the underlying pathophysiologic mechanisms of hemodynamic stress (i.e., natriuretic peptides), inflammation (i.e., C-reactive protein), and myocardial fibrosis identify patients at higher risk of developing AF. Circulating biomarkers can also be used to identify patients with AF who are at greatest risk for developing S/SEE or major bleeding. In particular, biomarkers of hemodynamic stress, myocardial injury (i.e., cardiac troponin), and coagulation activity (i.e., D-dimer) are key indicators of thromboembolic risk, and cardiac troponin and growth-differentiation factor-15 are strongly associated with risk of anticoagulant-related major bleeding. The biomarker-based age, biomarker, clinical history (ABC)-stroke and ABC-bleeding risk scores improve risk stratification for S/SEE and major bleeding, respectively, when compared with traditional clinical risk scores like the CHA2DS2-VASc and HAS-BLED scores.

Effectiveness and Safety of Direct Oral Anticoagulants in an Asian Population with Atrial Fibrillation Undergoing Dialysis: A Population-Based Cohort Study and Meta-Analysis.

PURPOSE: Whether direct oral anticoagulants (DOACs) are more effective and safer than warfarin among Asian patients with non-valvular atrial fibrillation (NVAF) undergoing dialysis remains unclear. METHODS: We first compared the risks of ischemic stroke/systemic embolism (IS/SE) and major bleeding associated with DOACs compared with warfarin, in NVAF Asians undergoing dialysis using the Taiwan National Health Insurance Research Database (NHIRD) (Aim 1). Next, we searched PubMed and Medline from January 1, 2010 until January 31, 2020, to perform a systematic review and meta-analysis of all observational real-world studies comparing DOACs with warfarin specifically focused on NVAF patients with stage 4 or 5 chronic kidney disease undergoing dialysis (Aim 2). Finally, we tested the hypothesis whether AF patients undergoing dialysis treated with OACs (warfarin and DOACs) would be associated with lower risk of adverse clinical outcomes as compared to those without OACs using the Taiwan NHIRD (Aim 3). RESULTS: From June 1, 2012, to December 31, 2017, a total of 3237 and 9263 NVAF patients comorbid with ESRD receiving oral anticoagulant (OACs) (490 on DOAC, 2747 on warfarin) or no OACs, respectively, were enrolled. Propensity score matching was used to balance covariates across the study groups. For the comparison of DOAC vs. warfarin (Aim 1), DOACs had comparable risks of IS/SE and major bleeding to warfarin in our present cohort. From the original 85 results retrieved, nine studies (including our study) with a total of 6490 and 22,494 patients treated with DOACs and warfarin were included in the meta-analysis, respectively. There were 5343 (82%) and 20,337 (90%) patients treated with DOACs and warfarin undergoing dialysis, respectively. The pooled meta-analysis also indicated no difference of the effectiveness (HR:0.90; [95%CI:0.74-1.10]; P = 0.32) and safety outcomes (HR:0.75; [95%CI:0.54-1.05]; P = 0.09) between DOACs and warfarin (Aim 2). For the comparison of OAC (+) vs. OAC (-) (Aim 3), OAC-treatment was associated with a higher risk of IS/SE (hazard ratio (HR):1.54; [95% confidential interval (CI):1.29-1.84];P < 0.0001) and comparable risk of major bleeding compared to those without OAC treatment. CONCLUSIONS: DOACs did not provide benefit over warfarin regarding effectiveness and safety in AF patients undergoing dialysis. The use of OAC was not associated with a lower risk of IS/SE in ESRD AF patients when compared to those without OAC use.

Benefit-Risk Tradeoffs in Assessment of New Drugs and Devices.

Balancing benefits and risks is a complex task that poses a major challenge, both to the approval of new medicines and devices by regulatory authorities and in therapeutic decision-making in practice. Several analysis methods and visualization tools have been developed to help evaluate and communicate whether the benefit-risk profile is favorable or unfavorable. In this White Paper, we describe approaches to benefit-risk assessment using qualitative approaches such as the Benefit Risk Action Team framework developed by the Pharmaceutical Research and Manufacturers of America, and the Benefit-Risk Framework developed by the United States Food and Drug Administration; and quantitative approaches such as the numbers needed to treat for benefit and harm, the benefit-risk ratio, and Incremental Net Benefit. We give illustrative examples of benefit-risk evaluations using 4 treatment interventions including sodium glucose cotransporter 2 inhibitors in patients with type 2 diabetes; a direct antithrombin agent, dabigatran, for reducing stroke and systemic embolism in patients with nonvalvular atrial fibrillation; transcatheter aortic valve replacement in patients with symptomatic severe aortic valve stenosis; and antiplatelet agents vorapaxar and prasugrel for reducing cardiovascular events in patients at high cardiovascular risk. Regular applications of structured benefit-risk assessment, whether qualitative, quantitative, or both, enabled by easy-to-understand graphical presentations that capture uncertainties around the benefit-risk metric, may aid shared decision-making and enhance transparency of those decisions.

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.

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.

Cost-effectiveness of Dabigatran Compared With Rivaroxaban for Prevention of Stroke and Systemic Embolism in Patients With Atrial Fibrillation in China.

PURPOSE: In China, dabigatran and rivaroxaban are the only approved non-vitamin K antagonist oral anticoagulants for the treatment of atrial fibrillation (AF). The goal of this article was to assess the cost-effectiveness of dabigatran versus rivaroxaban for the prevention of stroke and systemic embolism in Chinese patients with AF from the perspective of the Chinese health care system. METHODS: A Markov model was constructed to estimate the cost-effectiveness of dabigatran versus rivaroxaban. Clinical events were modeled for a lifetime horizon, based on clinical efficacy data from indirect treatment comparisons. The weighted average of the most recent prices of these 2 drugs was used as the drug acquisition cost. Other costs, including follow-up costs and event costs, were collected by using a survey from a panel of local experts. Utility inputs (health state utilities, clinical event disutilities, and event history utility) were obtained from published literature. Sensitivity analyses that included scenario analyses and a probabilistic sensitivity analysis were conducted to examine the robustness of the economic model. FINDINGS: Over a lifetime, patients treated with dabigatran experienced fewer ischemic strokes (2.14 dabigatran vs 2.61 rivaroxaban) and fewer intracranial hemorrhage (0.48 vs 0.94) per 100 patient-years. In the base case analysis, dabigatran had an incremental cost of ¥28,128 but with higher life years (10.38 vs 10.14) and quality-adjusted life years (QALYs) (7.95 vs 7.70). The resulting incremental cost-effectiveness ratio of ¥112,910 per QALY gained and net monetary benefit of ¥12,214 versus rivaroxaban showed that dabigatran was a cost-effective alternative to rivaroxaban. Extensive sensitivity analyses indicated that the results were robust over a wide range of inputs. The probabilistic sensitivity analysis indicated that dabigatran was cost-effective in 84.2% of the 10,000 Monte Carlo simulations compared with rivaroxaban. IMPLICATIONS: Dabigatran reduced the occurrence of clinical events and increased QALYs compared with rivaroxaban. The use of dabigatran for the prevention of stroke and systemic embolism is a cost-effective option compared with rivaroxaban among patients with AF in China.

Cost-effectiveness of rivaroxaban versus warfarin for stroke prevention in non-valvular atrial fibrillation in the Japanese healthcare setting.

Aims: This article aimed to examine the cost-effectiveness of rivaroxaban in comparison to warfarin for stroke prevention in Japanese patients with non-valvular atrial fibrillation (NVAF), from a public healthcare payer's perspective.Materials and methods: Baseline event risks were obtained from the J-ROCKET AF trial and the treatment effect data were taken from a network meta-analysis. The other model inputs were extracted from the literature and official Japanese sources. The outcomes included the number of ischaemic strokes, myocardial infarctions, systemic embolisms and bleedings avoided, life-years, quality-adjusted life-years (QALYs), incremental costs and incremental cost-effectiveness ratio (ICER). The scenario analysis considered treatment effect data from the same network meta-analysis.Results: In comparison with warfarin, rivaroxaban was estimated to avoid 0.284 ischaemic strokes per patient, to increase the number of QALYs by 0.535 per patient and to decrease the total costs by ¥118,892 (€1,011.11) per patient (1 JPY = 0.00850638 EUR; XE.com, 7 October 2019). Consequently, rivaroxaban treatment was found to be dominant compared to warfarin. In the scenario analysis, the ICER of rivaroxaban versus warfarin was ¥2,873,499 (€24,446.42) per QALY.Limitations: The various sources of data used resulted in the heterogeneity of the cost-effectiveness analysis results. Although, rivaroxaban was cost-effective in the majority of cases.Conclusion: Rivaroxaban is cost-effective against warfarin for stroke prevention in Japanese patients with NVAF, giving the payer WTP of 5,000,000 JPY.

Prevention of serious air embolism during cryoballoon ablation; risk assessment of air intrusion into the sheath by catheter selection and change in intrathoracic pressure: An ex vivo study.

INTRODUCTION: One cause of cerebral infarction during cryoballoon ablation is the entry of air into a sheath due to the use of inappropriate catheters. It is known that the left atrial pressure of patients with obstructive sleep apnea syndrome can be negative. However, the effects of catheter selection and negative pressure changes in the sheath on air intrusion are not yet well understood. The aim of this study was to evaluate how catheter selection and negative pressure changes affect air intrusion and to perform countermeasures for air intrusion. METHODS AND RESULTS: This experiment used siphon principle to create negative pressure in the sheath. Noncryoablation catheters (not designed exclusively for cryoballoon ablation) and cryoballoon catheters were investigated. Catheters were inserted into the sheath and then removed. Thereafter, the amount of air in the sheath was measured. For catheters producing significantly larger amounts of air intrusion, the catheters were inserted via a long sheath in the sheath (sheath-in-sheath technique) and the same procedures were repeated. We found that the amount of air intrusion through most of the noncryoablation catheters was significantly larger than that through cryoablation catheters. An increase in the magnitude of negative pressure in the sheath resulted in a proportional increase in air intrusion, but the sheath-in-sheath technique significantly reduced air intrusion. CONCLUSION: The amount of air intrusion increased when using catheters with complicated tip shapes and thin outer diameters and when the magnitude of negative pressure in the sheath increased. The sheath-in-sheath technique may be an effective countermeasure.

Cost-effectiveness of apixaban for stroke prevention in non-valvular atrial fibrillation in Saudi Arabia.

BACKGROUND: Apixaban, an oral anticoagulant for stroke and systemic embolism prevention in non-valvular atrial fibrillation (NVAF), was superior to warfarin in prevention of stroke and systemic embolism, bleeding outcomes and mortality (ARISTOTLE trial), and substantially reduced stroke risk, with no significant increase in major or intracranial bleeding risk versus aspirin (AVERROES trial). OBJECTIVE: Estimate cost-effectiveness of apixaban versus other anticoagulants for NVAF treatment in Saudi Arabia. DESIGN: Lifetime Markov model. SETTING: A published model was adapted from the United Kingdom (UK) to the Saudi Arabia setting. PATIENTS AND METHODS: The model enabled pairwise comparisons of apixaban against other anticoagulants, aspirin, and aspirin+clopidogrel. Apart from warfarin and aspirin, comparisons were indirect. Subpopulations included vitamin K antagonist (VKA) suitable and unsuitable patients. Medication and physician visit costs were from published lists. A cost ratio (0.533), from comparison of UK and Saudi physician visit costs, was applied to UK model inputs to estimate local event costs. Background life expectancy was from Saudi life tables. Model structure, treatment comparators, patient characteristics, event rates, and utilities were unchanged. Costs and health benefits were discounted by 3.5% annually. MAIN OUTCOME MEASURE: Incremental cost-effectiveness ratio of cost per quality-adjusted life-year (QALY) gained. SAMPLE SIZE: Model cohort of 1000 NVAF patients, for VKA suitable and VKA unsuitable populations. RESULTS: Apixaban was dominant versus warfarin (VKA suitable) and rivaroxaban (VKA suitable and unsuitable). Compared against dabigatran (110mg, 150 mg, 110/150mg), the cost/QALY gained for apixaban was $5166, $11 143, $10 849 (VKA suitable) and $5 157, $14 424, $14 134 (VKA unsuitable), respectively. Cost/QALY for apixaban versus aspirin and aspirin+clopidogrel was $14 805 and $5784 (VKA suitable); and $10 564 and $4203 (VKA unsuitable), respectively. Sensitivity analyses demonstrated consistency of findings across varying inputs. CONCLUSIONS: Apixaban was found to be cost-effective for stroke prevention among Saudi NVAF patients, when assessed using a US$20 000 willingness-to-pay threshold. LIMITATIONS: Lack of robust local clinical, cost and utility data for model inputs. Lack of head-to-head clinical trial data for rivaroxaban, dabigatran, and clopidogrel plus aspirin comparators. CONFLICT OF INTEREST: Study was funded by Pfizer Inc. and Bristol Myers-Squibb. KO, RS, SAK and AAA received salaries from their respective employers, but did not receive direct financial compensation for participation in or authorship of this study.

Would the Use of Edoxaban Be Cost-effective for the Prevention of Stroke and Systemic Embolism in Patients With Nonvalvular Atrial Fibrillation in Spain?

INTRODUCTION AND OBJECTIVES: To assess the cost-effectiveness of edoxaban vs acenocoumarol in the prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation (NVAF) in Spain. METHODS: Markov model, adapted to the Spanish setting from the perspective of the National Health System, stimulating the progression of a hypothetical cohort of patients with NVAF throughout their lifetime, with different health states: stroke, haemorrhage, and other cardiovascular complications. Efficacy and safety data were obtained from the available clinical evidence (mainly from the phase III ENGAGE AF-TIMI 48 study). The costs of managing NVAF and its complications were obtained from Spanish sources. RESULTS: Edoxaban use led to 0.34 additional quality-adjusted life years (QALY) compared with acenocoumarol. The incremental cost with edoxaban was 3916€, mainly because of higher pharmacological costs, which were partially offset by lower costs of treatment monitoring and managing NVAF events and complications. The cost per QALY was 11 518€, within the thresholds commonly considered cost-effective in Spain (25 000-30 000 €/QALY). The robustness of the results was confirmed by various sensitivity analyses. CONCLUSIONS: Edoxaban is a cost-effective alternative to acenocoumarol in the prevention of stroke and systemic embolism in patients with NVAF in Spain.

Real-World Comparative Effectiveness, Safety, and Health Care Costs of Oral Anticoagulants in Nonvalvular Atrial Fibrillation Patients in the U.S. Department of Defense Population.

BACKGROUND: The ARISTOTLE trial demonstrated that apixaban had significantly lower rates of stroke/systemic embolism (SE) and major bleeding than warfarin; however, no direct clinical trials between apixaban and other direct oral anticoagulants (DOACs) are available. Few real-world studies comparing the effectiveness and safety between DOACs have been conducted. OBJECTIVE: To compare effectiveness, safety, and health care costs among oral anticoagulants (OACs) for nonvalvular atrial fibrillation (NVAF) patients in the U.S. Department of Defense (DoD) population. METHODS: Adult NVAF patients initiating warfarin or DOACs (apixaban, rivaroxaban, and dabigatran) were selected from U.S. DoD data from January 1, 2013, to September 30, 2015. The first OAC claim date was designated as the index date. Patients initiating another OAC were matched 1:1 to apixaban patients using propensity score matching to balance demographics and clinical characteristics. Cox proportional hazards models were used to estimate the risk of stroke/SE and major bleeding for each OAC versus apixaban. Generalized linear and two-part models with bootstrapping were used to compare all-cause health care costs and stroke/SE-related and major bleeding-related medical costs. RESULTS: Of the 41,001 eligible patients, 7,607 warfarin-apixaban, 4,129 dabigatran-apixaban, and 11,284 rivaroxaban-apixaban pairs were matched. Warfarin (HR = 1.84; 95% CI = 1.30-2.59; P < 0.001) and rivar-oxaban (HR = 1.46; 95% CI = 1.08-1.98; P = 0.015) were associated with a significantly higher risk of stroke/SE compared with apixaban. Dabigatran (HR = 1.17; 95% CI = 0.68-2.03; P = 0.573) was associated with a numerically higher risk of stroke/SE compared with apixaban. Warfarin (HR = 1.53; 95% CI = 1.24-1.89; P < 0.001), dabigatran (HR = 1.76; 95% CI = 1.27-2.43; P < 0.001), and rivaroxaban (HR = 1.59; 95% CI = 1.34-1.89; P < 0.001) were associated with higher risks of major bleeding compared with apixaban. Compared with apixaban, patients prescribed warfarin incurred numerically higher all-cause total health care costs per patient per month (PPPM) ($2,498 vs. $2,277; P = 0.148) and significantly higher stroke/SE-related ($118 vs. $46; P = 0.012) and major bleeding-related ($166 vs. $76; P = 0.003) medical costs. Dabigatran patients incurred numerically higher all-cause total health care PPPM costs ($2,372 vs. $2,143; P = 0.150) and stroke/SE-related medical costs ($61 vs. $32; P = 0.240) but significantly higher major bleeding-related costs ($114 vs. $58; P = 0.025). Rivaroxaban patients incurred significantly higher all-cause total health care costs ($2,546 vs. $2,200; P < 0.001) and major bleeding-related medical costs PPPM ($137 vs. $69; P < 0.001) but numerically higher stroke/SE-related medical costs PPPM ($58 vs. $38; P = 0.057). CONCLUSIONS: Among NVAF patients in the U.S. DoD population, warfarin and rivaroxaban were associated with a significantly higher risk of stroke/SE and major bleeding compared with apixaban. Dabigatran use was associated with a numerically higher risk of stroke/SE and a significantly higher risk of major bleeding compared with apixaban. Warfarin and dabigatran incurred numerically higher all-cause total health care costs compared with apixaban. Rivaroxaban was associated with significantly higher all-cause total health care costs compared with apixaban. DISCLOSURES This study was funded by Bristol-Myers Squibb and Pfizer, which were involved in the study design, as well as in the writing and revision of the manuscript. Keshishian and Zhang are paid employees of STATinMED Research, which was paid by Bristol-Myers Squibb and Pfizer to conduct this study and develop the manuscript. Gupta, Rosenblatt, Hede, and Nadkarni are paid employees of Bristol-Myers Squibb. Trocio, Dina, Mardekian, Liu, and Shank are paid employees of Pfizer.

Renal function monitoring in patients prescribed dabigatran in the Compass Health Primary Health Organisation: a quality improvement audit.

AIM: To assess annual renal function monitoring and clinical indications for use in patients prescribed dabigatran. METHOD: A quality improvement activity included all patients in the Compass Health Primary Health Organisation (PHO) prescribed dabigatran. Information recorded: demographics; indication for use; daily dose; height; weight; serum creatinine; and estimated glomerular filtration rate (eGFR). The first audit occurred during July 2013 - May 2014, the second during May 2014 - October 2016. RESULTS: Across the PHO, all patients prescribed dabigatran were reviewed: 941 patients and 1,564 respectively. At the time of the second pass audit, renal function monitoring improved from 88% to 90%, and 96% were prescribed dabigatran for an approved indication. CONCLUSION: Results showed a continuing high level of renal function monitoring across the PHO in 90% of patients prescribed dabigatran. Practitioners were reminded to use creatinine clearance as a marker of renal function. Dabigatran was prescribed for an approved indication in 96% of patients. Our results are in line with recommended best practice and clinical guidelines.

Risk of stroke/systemic embolism, major bleeding and associated costs in non-valvular atrial fibrillation patients who initiated apixaban, dabigatran or rivaroxaban compared with warfarin in the United States Medicare population.

OBJECTIVE: To compare the risk and cost of stroke/systemic embolism (SE) and major bleeding between each direct oral anticoagulant (DOAC) and warfarin among non-valvular atrial fibrillation (NVAF) patients. METHODS: Patients (≥65 years) initiating warfarin or DOACs (apixaban, rivaroxaban, and dabigatran) were selected from the Medicare database from 1 January 2013 to 31 December 2014. Patients initiating each DOAC were matched 1:1 to warfarin patients using propensity score matching to balance demographics and clinical characteristics. Cox proportional hazards models were used to estimate the risks of stroke/SE and major bleeding of each DOAC vs. warfarin. Two-part models were used to compare the stroke/SE- and major-bleeding-related medical costs between matched cohorts. RESULTS: Of the 186,132 eligible patients, 20,803 apixaban-warfarin pairs, 52,476 rivaroxaban-warfarin pairs, and 16,731 dabigatran-warfarin pairs were matched. Apixaban (hazard ratio [HR] = 0.40; 95% confidence interval [CI] 0.31, 0.53) and rivaroxaban (HR = 0.72; 95% CI 0.63, 0.83) were significantly associated with lower risk of stroke/SE compared to warfarin. Apixaban (HR = 0.51; 95% CI 0.44, 0.58) and dabigatran (HR = 0.79; 95% CI 0.69, 0.91) were significantly associated with lower risk of major bleeding; rivaroxaban (HR = 1.17; 95% CI 1.10, 1.26) was significantly associated with higher risk of major bleeding compared to warfarin. Compared to warfarin, apixaban ($63 vs. $131) and rivaroxaban ($93 vs. $139) had significantly lower stroke/SE-related medical costs; apixaban ($292 vs. $529) and dabigatran ($369 vs. $450) had significantly lower major bleeding-related medical costs. CONCLUSIONS: Among the DOACs in the study, only apixaban is associated with a significantly lower risk of stroke/SE and major bleeding and lower related medical costs compared to warfarin.

How well does physician risk assessment predict stroke and bleeding in atrial fibrillation? Results from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF).

BACKGROUND: Assessments of stroke and bleeding risks are essential to selecting oral anticoagulation in patients with atrial fibrillation (AF). We aimed to assess outcomes according to physician assessed risk, with comparison to empirical risk scores. METHODS: This was a prospective, observational study of 9,715 outpatients with AF enrolled in ORBIT-AF, a US national registry. Stroke and bleeding risks were quantified by physician assignment, CHADS2 and CHA2DS2-VASc stroke scores, and ATRIA and HAS-BLED bleeding scores. Outcomes were stroke or systemic embolism and major bleeding during a median follow-up of 28 months. RESULTS: Physician-assigned risk was associated with thromboembolic events: low risk (0.71 per 100 patient-years [95% CI 0.56-0.91], n=3,991), intermediate risk (0.98 [95% CI 0.79-1.20], n=4,148), and high risk (1.84 [95% CI 1.43-2.37], n=1,576, P<.0001), and major bleeding: low (3.43 [95% CI 3.07-3.82], n=4,250), intermediate (4.55 [95% CI 4.03-5.15], n=2,702), and high (5.76 [95% CI 4.42-7.50], n=468; P<.0001). Discrimination of stroke risk was similar with CHADS2 (c=0.59, 95% CI 0.57-0.61) vs physician assessment (c=0.58, 95% CI 0.55-0.62). Among patients on oral anticoagulation, bleeding risk discrimination was higher with ATRIA (c=0.63, 95% CI 0.61-0.65) and HAS-BLED (c=0.60, 95% CI 0.59-0.62) than with physician assessment (0.55, 95% CI 0.53-0.57). Physician-assessed risk categories did not add significantly to empirical risk scores, in Cox models for outcomes (Padjusted>.05 for all physician assessments vs Padjusted<.05 for empirical scores). CONCLUSION: Physician-assigned risk showed a graded relationship with outcomes, and both physician-based and empirical scores yielded only moderate discrimination. Although empirical scores provided valuable risk stratification information (with or without physician judgment), physician assessment added little to existing scores. These data support the use of empirical scores for stroke and bleeding risk stratification, and the need for novel approaches to risk stratification in this population.