Adoption of direct oral anticoagulants for stroke prevention in atrial fibrillation

Evolving Trends in Consumption of Direct Oral Anticoagulants in 65 Countries/Regions from 2008 to 2019

BACKGROUND

Direct oral anticoagulants (DOACs) have been increasingly utilised over warfarin. However, little is known about the relative consumption trends and costs of each DOAC at the global level.

METHODS

An ecological study using pharmaceutical sales data from IQVIA-MIDAS database was used to estimate consumption and cost of individual DOACs in 65 countries from 2008 to 2019. Consumption was estimated from the volume of DOACs sold, expressed as defined-daily-dose/1000-inhabitants/day (DDDTID). Compound and absolute annual growth rates were reported to quantify consumption changes over time. Costs were estimated as manufacturer price per day-of-therapy.

RESULTS

Global consumption of dabigatran, rivaroxaban, apixaban and edoxaban were 0.31, 1.05, 1.08 and 0.78 DDDTID, respectively, in Q2-2019, compared to 0.23, 0.54, 0.21 and 0.03 in Q2-2015, with highest consumption in Western Europe, Northern Europe and Oceania (18.2, 14.07, 13.14 DDDTID). In most countries (46/65, 70%), rivaroxaban contributed to most DOAC consumption (35%-100%), whereas dabigatran accounted for less than one-third. Edoxaban accounted for < 20% of the total in Northern America and Europe but contributed significant proportions in Japan (28.58%) and South Korea (31.37%). Longer median time-to-adoption from FDA approval for apixaban and edoxaban was observed. Costs of all DOACs were ~2-4 times higher in the USA, Puerto Rico and Thailand than in other countries.

CONCLUSIONS

Regional differences exist in consumption pattern and trends of individual DOACs over the past decade. Consumption of rivaroxaban and apixaban overtook dabigatran in most countries, whereas use of edoxaban remains limited except in East Asian countries. The USA pays higher prices for DOACs than other countries.

Cobalt-Catalyzed Asymmetric 1,4-Hydroboration of Enones with HBpin

Herein, a series of new 8-OIQ cobalt complexes were synthesized and used for cobalt-catalyzed chemo- and enantioselective 1,4-hydroboration of enones with HBpin to access chiral β,β-disubstituted ketones with good to excellent chemo- and enantioselectivties. This protocol is operationally simple and shows a broad substrate scope.

Comparative effects of telemedicine and face-to-face warfarin management: A systematic review and network meta-analysis

OBJECTIVE

To determine the comparative effects of different types of telemedicine on anticoagulation control and adverse outcomes in patients taking warfarin.

DATA SOURCES

A systematic search was conducted in PubMed, the Cochrane library, EMBASE, CINAHL, OpenGrey, and DART-Europe from inception to September 2019.

STUDY SELECTION

Randomized controlled trials, quasi-experimental and cohort studies were included if they evaluated the effect of telemedicine in patients using warfarin for 3 months or more.

METHODS

Two reviewers extracted and assessed the quality of studies by means of the Cochrane Effective Practice and Organization of Care Group. Network meta-analyses were performed using a random-effects model. Surface under the cumulative ranking curve (SUCRA) methods were used to rank different telemedicine types.

RESULTS

Of the 14,673 articles retrieved, 12 studies involving 11,478 patients met the inclusion criteria. The 5 types of telemedicine categorized were 1) laboratory draw with individual telephonic follow-up by health care (HC) providers (Lab/Tel/HC); 2) laboratory draw with individual telephonic follow-up with periodic, routine routine face-to-face (F2F) visit (Lab/Tel+F2F/HC); 3) laboratory draw with individual and group follow-up via online access (Lab/Online/HC); 4) patient self-test (PST) with telephonic or Web-based follow-up by automated management system (PST/Tel-Online/Auto); and 5) PST with telephonic follow-up by HC provider (PST/Tel/HC). PST/Tel-Online/Auto appears to be superior to F2F for TTR (mean difference 8.78%; 95% CI 0.06%-17.50%) and Lab/Online/HC for in-range INR (odds ratio 2.59; 95% CI 1.04-6.46). The SUCRAs suggested that PST/Tel-Online/Auto was preferred for both TTR and INR, at 84.2% and 93.9%, respectively, whereas Lab/Tel/HC was preferred to prevent major bleeding (74.1%) or thromboembolic event (70.7%).

CONCLUSION

According to the current evidence of uncertain quality, the best effects on anticoagulation control and adverse outcomes were achieved from different types of telemedicine. Variations in the effects of telemedicine on diverse outcomes should be considered before implementing telemedicine interventions in patients taking warfarin.

Trends in anticoagulant prescribing: a review of local policies in English primary care

Background

Oral anticoagulants are prescribed for stroke prophylaxis in patients with atrial fibrillation, which is the most common heart arrhythmia worldwide. The vitamin K antagonist (VKA) warfarin is a long-established anticoagulant. However, newer direct oral anticoagulants (DOACs) have been recently introduced as an alternative. Given the prevalence of atrial fibrillation, anticoagulant choice has substantial clinical and financial implications for healthcare systems. In this study, we explore trends and geographic variation in anticoagulant prescribing in English primary care. Because national guidelines in England do not specify a first-line anticoagulant, we investigate the association between local policies and prescribing data.

Methods

Primary care prescribing data of anticoagulants for all NHS practices from 2014 to 2019 in England was obtained from the ePACT2 database. Public formularies were accessed online to obtain local anticoagulation prescribing policies for 89.5% of clinical commissioning groups (CCGs). These were categorized according to their recommendations: no local policies, warfarin as first-line, or identification of a preferred DOAC (but not a preferred anticoagulant). Local policies were cross-tabulated with pooled prescribing data to measure the strength of association with Cramér’s V.

Results

Nationally, prescribing of DOACs increased from 9% of all anticoagulants in 2014 to 74% in 2019, while that of warfarin declined accordingly. Still, there was significant local variation. Across geographical regions, DOACs ranged from 53 to 99% of all anticoagulants. Most CCGs (73%) did not specify a first-line choice, and 16% recommended warfarin first line. Only 11% designated a preferred DOAC. Policies with a preferred DOAC indeed correlated with increased prescribing of that DOAC (Cramér’s V = 0.25, 0.27, 0.38 for rivaroxaban, apixaban, edoxaban respectively). However, local policies showed a negligible relationship with the classes of anticoagulants prescribed—DOAC or VKA (Cramér’s V = 0.01).

Conclusions

Nationally, the use of DOACs to treat atrial fibrillation has increased rapidly. Despite this, significant geographical variation in uptake remains. This study provides insights on how local policies relate to this variation. Our findings suggest that, in the absence of a nationally recommended first-line anticoagulant, local prescribing policies may aid in deciding between individual DOACs, but not in adjudicating between DOACs and vitamin K antagonists (i.e. warfarin) as general classes.

Oral anticoagulants usage in Japanese patients aged 18-74 years with non-valvular atrial fibrillation: a retrospective analysis based on insurance claims data

BACKGROUND

Oral anticoagulants use has increased rapidly, internationally. Here we look at risks and benefits, based on Japanese data, of therapy with low risk non-valvular atrial fibrillation patients.

OBJECTIVES

Using a health insurance claims data set we assessed: (i) oral anticoagulants usage in Japan, and (ii) efficacy and safety of dabigatran compared with warfarin, in Japanese patients with non-valvular atrial fibrillation, aged 18-74 years.

METHODS

We identified 4380 non-valvular atrial fibrillation patients treated with anticoagulants between 1 January 2005, and 28 February 2014, and estimated the adjusted hazard ratio for stroke or systemic embolism, and any hemorrhagic event (Cox proportional hazards regression model with stabilized inverse probability treatment weighting).

RESULTS

The data included 101 989 anticoagulant prescriptions for 4380 patients, of which direct oral anticoagulants increased to 40.0% of the total by the end of the study. After applying exclusion criteria, 1536 new non-valvular atrial fibrillation patients were identified, including 1071 treated with warfarin and 465 with dabigatran. Mean ages were 56.11 ± 9.70 years for warfarin, and 55.80 ± 9.65 years for dabigatran. The adjusted hazard ratio (95% confidence interval), comparing dabigatran with warfarin, was 0.48 (0.25-0.91) for stroke or systemic embolism, and 0.91 (0.60-1.39) for any hemorrhage including intracranial and gastrointestinal.

CONCLUSIONS

Number of patients prescribed direct oral anticoagulants steadily increased, and incidence of all-cause bleeding related to dabigatran was similar to warfarin, in our study population of younger non-valvular atrial fibrillation patients. Dabigatran, compared with warfarin, generally reduced risk of all-cause stroke and systemic embolism.

Association Between Warfarin Control Metrics and Atrial Fibrillation Outcomes in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation

Importance

Bleeding and thrombotic events (eg, stroke and systemic embolism) are common in patients with atrial fibrillation (AF) taking warfarin sodium despite a well-established therapeutic range.

Objective

To evaluate whether history of therapeutic warfarin control in patients with AF is independently associated with subsequent bleeding or thrombotic events.

Design, Setting, and Participants

In this multicenter cohort study of 176 primary care, cardiology, and electrophysiology clinics in the United States, data were obtained during 51 830 visits among 10 137 patients with AF in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) Registry; 5545 patients treated with warfarin were included in the bleeding analysis, and 5635 patients were included in the thrombotic event analysis. Patient follow-up was performed from June 29, 2010, to November 30, 2014. Data analysis was performed from August 4, 2016, to February 15, 2019.

Exposures

Multiple measures of warfarin control within the preceding 6 months were analyzed: time in therapeutic range of 2.0 to 3.0, most recent international normalized ratio (INR), percentage of time that a patient had interpolated INR values less than 2.0 or greater than 3.0, INR variance, INR range, and percentage of INR values in therapeutic range.

Main Outcomes and Measures

Association of INR measures, alone or in combination, with clinical factors and risk for thrombotic events and bleeding during the subsequent 6 months was assessed post hoc using logistic regression models.

Results

A total of 5545 patients (mean [SD] age, 74.5 [9.8] years; 3184 [57.4%] male) with AF were included in the major bleeding analysis and 5635 patients (mean [SD] age, 74.5 [9.8] years; 3236 [57.4%] male) in the thrombotic event analysis. During a median follow-up of 1.5 years (interquartile range, 1.0-2.5 years), there were 339 major bleeds (6.1%) and 51 strokes (0.9%). Multiple metrics of warfarin control were individually associated with subsequent bleeding. After adjustment for clinical bleeding risk, 3 measures-time in therapeutic range (per 1-SD increase ≤55: adjusted odds ratio [aOR], 1.16; 95% CI, 1.02-1.32), variation in INR values (aOR, 1.32; 95% CI, 1.19-1.47), and maximum INR (aOR, 1.20; 95% CI, 1.10-1.31)-remained associated with bleeding risk. Adding INR variance to a clinical risk model slightly increased the C statistic from 0.68 to 0.69 and had a net reclassification improvement index of 0.028 (95% CI, -0.029 to 0.067). No INR measures were associated with subsequent stroke risk.

Conclusions and Relevance

Three metrics of prior warfarin control were associated with bleeding risk but only marginally more so than traditional clinical factors. This study did not identify any measures of INR control that were significantly associated with stroke risk.

Laboratory measurement of apixaban using anti-factor Xa assays in acute ischemic stroke patients with non-valvular atrial fibrillation

Apixaban is effective and safe for preventing stroke, and its usage has increased exponentially in recent years. However, data concerning the therapeutic range of apixaban is limited. This study determined the trough and peak levels of apixaban-specific anti-factor Xa activity (AFXaA) in acute ischemic stroke patients with non-valvular atrial fibrillation (NVAF) in Korea. The study included 85 patients who received apixaban. Blood samples were taken to measure the trough and peak levels of AFXaA using a chromogenic anti-factor assay, as well as prothrombin time (PT) and activated partial thromboplastin time (aPTT). We also reviewed complications such as major bleeding of patients treated with apixaban. In patients given a 5.0-mg apixaban dose, the median trough and peak levels of AFXaA were 104.5 and 202.0 ng/mL. In patients given a 2.5-mg apixaban dose, the median trough and peak AFXaA levels were 76.0 and 151.0 ng/mL. The PT showed a positive correlation with increased AFXaA activity at both levels (Trough R = 0.486, Peak R = 0.592), but the aPTT had no relationship with AFXaA activity at both levels (Trough R = 0.181, Peak R = 0.129). Two cases with intracranial bleeding belonged to the highest AFXaA quartile (Trough, p = 0.176; Peak, p = 0.053). In conclusion, we determined the trough and peak levels of AFXaA in patients with NVAF while being treated with the apixaban in Korea. Our results could be used as a starting point when setting the reference ranges for laboratories using anti-Xa assay. Large-scale studies are needed to establish the reference range for AFXaA in patients with NVAF.

Trends and Variation in Oral Anticoagulant Choice in Patients with Atrial Fibrillation, 2010-2017

OBJECTIVE

Since 2010, several non-vitamin K antagonist oral anticoagulants (NOACs) have been brought to the U.S. market, yet little is known regarding their evolving adoption for prophylaxis of atrial fibrillation (AF)-related stroke. We examined temporal trends in choice of oral anticoagulants (OACs) among incident OAC users with AF and its association with patient demographic and clinical characteristics.

METHODS

We conducted a serial cross-sectional analysis of medical and pharmacy claims for commercial and Medicare Advantage enrollees in a large, private, U.S. health plan. We identified 112,187 adults with nonvalvular AF starting OACs between October 2010 and March 2017. Multivariable logistic regression was used to examine the associations of patient characteristics with prescription of NOACs versus warfarin. Multinomial logistic regression was used to test the associations of patient characteristics with choice among NOACs.

RESULTS

The prescription of NOACs has increased dramatically since their introduction in October 2010. In the first quarter of 2017 (2017Q1), 7502 patients started OACs, of whom 78.9% used NOACs and 21.1% warfarin. For NOACs, 3.8% used dabigatran, 25.0% rivaroxaban, and 50.1% apixaban. In multivariable analyses, factors associated with choice of NOACs versus warfarin included younger age, lower stroke or bleeding risk, fewer comorbidities, higher education level or household net worth, and prescription by cardiologists (all p<0.001). There was no sex difference in likelihood of filling NOACs versus warfarin in 2010Q4-2012, but women had higher odds of starting NOACs (odds ratio = 1.19; 95% confidence interval = 1.14-1.25) in 2015-2017Q1. Among NOAC users, the odds of apixaban prescription increased with age, female sex, stroke or bleeding risk, and comorbidities (all p<0.05).

CONCLUSION

NOAC prescriptions have increased substantially among incident OAC users with nonvalvular AF, predominantly driven by increased prescription of apixaban. Warfarin and apixaban were generally preferred for elderly patients, patients with higher stroke or bleeding risk, and patients with more comorbidities.

Adherence to Oral Anticoagulants in Atrial Fibrillation: An Australian Survey

Background:

The aim of this study was to investigate the proportion of patients who have suboptimal adherence to oral anticoagulant (OAC), identify the predictors of adherence, and determine whether patient-related factors vary across adherence levels in Australia.

Methods:

Respondents were recruited for an online survey using Facebook. Survey instruments included the Morisky Medication Adherence Scale, the Anticoagulation Knowledge Tool, the Perception of Anticoagulant Treatment Questionnaires, and a modified Cancer Information Overload scale. Predictors of medication adherence were identified using ordinal regression analysis.

Results:

Of the 386 responses eligible for analysis, only 54.9% reported a high level of adherence. Participants aged 65 years or younger were less likely to have high adherence compared to older participants (odds ratio [OR], 0.54; 95% confidence interval [CI], 0.33-0.88; P = .013), while females were more likely to be highly adherent compared to males (OR, 1.69; 95% CI, 1.08-2.64; P = .023). The analyses showed that age, gender, treatment satisfaction, information overload, concerns about making mistake when taking OACs, and cost of medication were significant predictors of adherence.

Conclusion:

Self-reported suboptimal adherence to OAC is common among patients with atrial fibrillation. A focus on supporting people who are at higher risk of suboptimal adherence is needed to maximize the benefit of OAC therapy in this population.

Trends in the prescription of novel oral anticoagulants in UK primary care

AIMS

Novel oral anticoagulants (NOACs) are alternatives to vitamin-K antagonists (VKAs) for the prevention of thromboembolism. It is unclear how NOACs have been adopted in the UK since first introduced in 2008. The present study was conducted to describe the trends in the prescription of NOACs in the UK, including dabigatran, rivaroxaban and apixaban.

METHODS

Using the UK's Clinical Practice Research Datalink, the rates of new use of NOACs and VKAs from 2009 to 2015 were calculated using Poisson regression. Patient characteristics associated with NOAC initiation were identified using multivariate logistic regression.

RESULTS

The overall rate of oral anticoagulant initiation increased by 58% over the study period [rate ratio (RR) 1.58; 95% confidence interval (CI) 1.23, 2.03], even as the rate of new VKA use decreased by 31% (RR 0.69; 95% CI 0.52, 0.93). By contrast, the rate of initiation of NOAC increased, particularly from 2012 onwards, with a 17-fold increase from 2012 to 2015 (RR 17.68; 95% CI 12.16, 25.71). In 2015, NOACs accounted for 56.5% of oral anticoagulant prescriptions, with rivaroxaban prescribed most frequently, followed by apixaban and then dabigatran. Compared to VKAs, new NOAC users were less likely to have congestive heart failure, coronary artery disease and peripheral vascular disease, and more likely to have a history of ischaemic stroke.

CONCLUSIONS

In the UK, the rate of initiation of NOACs has increased substantially since 2009, and these agents have now surpassed VKAs as the anticoagulant of choice. Moreover, the characteristics of patients initiated on NOACs have changed over time, and this should be accounted for in future studies comparing NOACs and VKAs.

Prescribing trends of atrial fibrillation patients who switched from warfarin to a direct oral anticoagulant

Direct oral anticoagulant (DOAC) agents offer several lifestyle and therapeutic advantages for patients relative to warfarin in the treatment of atrial fibrillation (AF). These alternative agents are increasingly used in the treatment of AF, however the adoption practices, patient profiles, and reasons for switching to a DOAC from warfarin have not been well studied. Through the Michigan Anticoagulation Quality Improvement Initiative, abstracted data from 3873 AF patients, enrolled between 2010 and 2015, were collected on demographics and comorbid conditions, stroke and bleeding risk scores, and reasons for anticoagulant switching. Over the study period, patients who switched from warfarin to a DOAC had similar baseline characteristics, risk scores, and insurance status but differed in baseline CrCl. The most common reasons for switching were patient related ease of use concerns (37.5%) as opposed to clinical reasons (16.5% of patients). Only 13% of patients that switched to a DOAC switched back to warfarin by the end of the study period.

Highly efficient synthesis of chiral aromatic ketones via Rh-catalyzed asymmetric hydrogenation of β,β-disubstituted enones

A series of chiral aromatic ketones were achieved with excellent enantioselectivities via Rh–ZhaoPhos catalyzed asymmetric hydrogenation of β,β-disubstituted enones.