Comparative effectiveness and safety of non-vitamin K antagonist oral anticoagulants and warfarin in patients with atrial fibrillation: propensity weighted nationwide cohort study

Apixaban for Stroke Prevention in Atrial Fibrillation: Why are Event Rates Higher in Clinical Practice than in Randomized Trials?—A Systematic Review

Background Recent reports suggest an important contribution from frequent off-label use of apixaban 2.5 mg twice daily to the higher rates of thromboembolic events observed in observational studies (OSs) relative to in randomized controlled trials (RCTs), and consequently, advocate against such use in all patients.

Objectives To examine factors contributing to the higher thromboembolic event rates, we estimated the prevalence of off-label use in contemporary practice, and compared patient characteristics and rates of stroke/systemic embolism, major bleeding, and mortality by apixaban dose and by study design in a systematic review and meta-analysis.

Results and Discussion We identified 18 OSs and 2 RCTs that included 155,228 and 11,928 patients, respectively. Patients in OSs more often received apixaban 2.5 mg twice daily (31.3% vs. 5.1%), were older (mean age 73.8 vs. 69.8 years), and had higher CHA2DS2-VASc scores (mean 3.6 vs. 2.9) versus those in RCTs. We observed a consistent pattern of higher rates of thromboembolic events, bleeding, and mortality in patients treated with 2.5 versus 5 mg twice daily apixaban in both OSs and RCTs.

Conclusion The higher risk profiles of patients in OSs versus RCTs, and higher rates of both bleeding and mortality not attributable to thromboembolism in patients treated with apixaban 2.5 versus 5 mg twice daily suggest that differences in patient characteristics are additional important contributors to the higher than expected thromboembolic event rates in clinical practice.

Comparing risk of major bleeding between users of different oral anticoagulants in patients with nonvalvular atrial fibrillation

AIMS

The introduction of direct oral anticoagulants (DOACs) has broadened the treatment arsenal for nonvalvular atrial fibrillation, but observational studies on the benefit-risk balance of DOACs compared to vitamin K antagonists (VKAs) are needed. The aim of this study was to characterize the risk of major bleeding in DOAC users using longitudinal data collected from electronic health care databases from 4 different EU-countries analysed with a common study protocol.

METHODS

A cohort study was conducted among new users (≥18 years) of DOACs or VKAs with nonvalvular atrial fibrillation using data from the UK, Spain, Germany and Denmark. The incidence of major bleeding events (overall and by bleeding site) was compared between current use of DOACs and VKAs. Cox regression analysis was used to calculate hazard ratios and 95% confidence intervals (CI) and adjust for confounders.

RESULTS/CONCLUSION

Overall, 251 719 patients were included across the 4 study cohorts (mean age ~75 years, % females between 41.3 and 54.3%), with overall hazard ratios of major bleeding risk for DOACs vs VKAs ranging between 0.84 (95% CI: 0.79-0.90) in Denmark and 1.13 (95% CI 1.02-1.25) in the UK. When stratifying according to the bleeding site, risk of gastrointestinal bleeding was increased by 48-67% in dabigatran users and 30-50% for rivaroxaban users compared to VKA users in all data sources except Denmark. Compared to VKAs, apixaban was not associated with an increased risk of gastrointestinal bleeding in all data sources and seemed to be associated with the lowest risk of major bleeding events compared to dabigatran and rivaroxaban.

Comparative Safety and Effectiveness of Oral Anticoagulants in Nonvalvular Atrial Fibrillation: The NAXOS Study

Supplemental Digital Content is available in the text.

Background and Purpose:

The effects of direct oral anticoagulants in nonvalvular atrial fibrillation should be assessed in actual conditions of use. France has near-universal healthcare coverage with a unified healthcare information system, allowing large population-based analyses. NAXOS (Evaluation of Apixaban in Stroke and Systemic Embolism Prevention in Patients With Nonvalvular Atrial Fibrillation) aimed to compare the safety, effectiveness, and mortality of apixaban with vitamin K antagonists (VKAs), rivaroxaban, and dabigatran, in oral anticoagulant-naive patients with nonvalvular atrial fibrillation.

Methods:

This was an observational study using French National Health System claims data and including all adults with nonvalvular atrial fibrillation who initiated oral anticoagulant between 2014 and 2016. Outcomes of interest were major bleeding events leading to hospitalization (safety), stroke and systemic thromboembolic events (effectiveness), and all-cause mortality. Four approaches were used for comparative analyses: matching on propensity score (PS; 1:n); as a sensitivity analysis, matching on high-dimensional PS; adjustment on PS; and adjustment on known confounders. For each outcome, cumulative incidence rates accounting for competing risks of death were estimated.

Results:

Overall, 321 501 patients were analyzed, of whom 35.0%, 27.2%, 31.1%, and 6.6% initiated VKAs, apixaban, rivaroxaban, and dabigatran, respectively. Apixaban was associated with a lower PS–matched risk of major bleeding compared with VKAs (hazard ratio [HR], 0.43 [95% CI, 0.40–0.46]) and rivaroxaban (HR, 0.67 [95% CI, 0.63–0.72]), but not dabigatran (HR, 0.93 [95% CI, 0.81–1.08]). Apixaban was associated with a lower risk of stroke and systemic thromboembolic event compared with VKAs (HR, 0.60 [95% CI, 0.56–0.65]), but not rivaroxaban (HR, 1.05 [95% CI, 0.97–1.15]) or dabigatran (HR, 0.93 [95% CI, 0.78–1.11]). All-cause mortality was lower with apixaban than with VKAs, but not lower than with rivaroxaban or dabigatran.

Conclusions:

Apixaban was associated with superior safety, effectiveness, and lower mortality than VKAs; with superior safety than rivaroxaban and similar safety to dabigatran; and with similar effectiveness when compared with rivaroxaban or dabigatran. These observational data suggest potentially important differences in outcomes between direct oral anticoagulants, which should be explored in randomized trials.

Major bleeding risk associated with oral anticoagulant in real clinical practice. A multicentre 3-year period population-based prospective cohort study

AIMS

The objective was to compare major bleeding risk of direct oral anticoagulants (DOACs; per type and dose) with vitamin K antagonists (VKAs), irrespective of indication, using real-world data.

METHODS

A population-based prospective cohort study, using the French national health data system (SNIIRAM), identified 47 469 adults living within 5 well-defined geographical areas, who were new users of oral anticoagulants in the period 2013-2015: 20 205 VKA users, 19 579 rivaroxaban users, 4225 dabigatran users and 3460 apixaban users. From all emergency departments within these areas, clinical data for all adults referred for bleeding was collected and medically validated. The databases were linked for common key variables. The main outcome measure was major bleeding: intracranial haemorrhage, major gastrointestinal bleeding and other major bleeding events. Hazard ratios were derived from adjusted Cox proportional hazard models. We used propensity score weighting as a sensitivity analysis, with separate analyses according to indications (atrial fibrillation or venous thromboembolism).

RESULTS

Compared to VKAs, high and low-dose DOACs were associated with a reduced risk of intracranial haemorrhage (adjusted hazard ratio 0.55, 95% confidence interval 0.37-0.82 and 0.54, 0.26-1.12 respectively), and a reduced risk of other major bleeding events (0.41, 0.29-0.58 and 0.41, 0.22-0.79 respectively), irrespective of duration and indication. Neither DOAC dose evidenced any significant difference from VKAs in terms of risk of major gastrointestinal bleeding.

CONCLUSION

There is a clear benefit of using DOACs with regard to intracranial haemorrhage. The study provides new insight into major gastrointestinal and other major bleeding events.

Association of Ischemic Stroke, Major Bleeding, and Other Adverse Events With Warfarin Use vs Non-vitamin K Antagonist Oral Anticoagulant Use in Patients With Atrial Fibrillation With a History of Intracranial Hemorrhage

IMPORTANCE

Current guidelines recommend the use of non-vitamin K antagonist oral anticoagulants (NOACs) for stroke prevention in patients with atrial fibrillation (AF). Data regarding warfarin sodium use compared with NOAC use in patients with AF with a history of intracranial hemorrhage (ICH) are limited.

OBJECTIVE

To compare the clinical outcomes of warfarin use and NOAC use in patients with AF with a history of ICH using a nationwide cohort with AF.

DESIGN, SETTING, AND PARTICIPANTS

A nationwide cohort study from January 1, 2012, to December 31, 2016, was performed using data from the Taiwan National Health Insurance Research Database. The dates of analysis were July 1 to September 1, 2019. The study population comprised patients with AF with a history of ICH and a CHA2DS2-VASc score (congestive heart failure, hypertension, age ≥75 years [doubled], diabetes, prior stroke/transient ischemic attack/thromboembolism [doubled], vascular disease [prior myocardial infarction, peripheral artery disease], age 65-74 years, sex category [female]) of at least 1 for men or at least 2 for women who had received warfarin or NOACs. The clinical outcomes were examined using Cox proportional hazards regression analyses among the study population before and after propensity score matching.

EXPOSURES

Oral anticoagulation with warfarin or NOACs.

MAIN OUTCOMES AND MEASURES

The clinical outcomes measured were all-cause mortality, ischemic stroke, ICH, major bleeding, and adverse events.

RESULTS

The study cohort included 4540 patients (mean [SD] age, 76.0 [10.5] years; 2653 men [58.4%]), with 1047 patients receiving warfarin (mean [SD] age, 75.1 [11.4] years; 571 men [54.5%]) and 3493 patients receiving NOACs (mean [SD] age, 76.3 [10.2] years; 2082 men [59.6%]). Compared with warfarin use, NOAC use was associated with statistically significantly lower risk of all-cause mortality (adjusted hazard ratio [aHR], 0.517; 95% CI, 0.457-0.585), ICH (aHR, 0.556; 95% CI, 0.389-0.796), and major bleeding (aHR, 0.645; 95% CI, 0.525-0.793), whereas the rate of ischemic stroke was similar in the 2 groups (aHR, 0.879; 95% CI, 0.678-1.141). These results were generally consistent after propensity score matching among 973 patients in each group.

CONCLUSIONS AND RELEVANCE

Among patients with AF with prior ICH, NOAC use was associated with lower rates of ICH and major bleeding compared with warfarin use, whereas the rate of ischemic stroke was similar in the 2 groups. Among patients with AF with prior ICH, NOACs could be the preferred choice for stroke prevention.

Uptake of direct oral anticoagulants in primary care: an ecological and economic study

Background

Clinical trials indicate that direct oral anticoagulants (DOACs) are as effective as warfarin at preventing ischaemic stroke. It is unclear, however, whether relative changes in DOAC uptake have affected clinical and economic outcomes in practice.

Aim

To investigate variations in DOAC uptake and the relationship with hospital admissions and cost.

Design & setting

An ecological study using electronic administrative records from England, April 2012 to March 2017.

Method

Multivariable regression was used to model practice variation in DOAC prescribing, and the relationship with clinical and economic outcomes.

Results

In quarter 1 of 2017, 55.0% of the 2 695 262 patients dispensed an anticoagulant were given a DOAC. There was a two-fold difference in odds of dispensing DOACs between clinical commissioning groups (CCGs) between those with the highest and lowest usage of these drugs. Increases in the relative uptake of DOACs were not associated with hospital admissions for ischaemic stroke (adjusted incidence rate ratio [IRR] = 1.00; 95% confidence intervals [CI] = 0.999 to 1.001), nor gastrointestinal or intracranial bleeds (IRR = 1.001; 95% CI = 1.000 to 1.002). In 2017, quarter 1, CCGs spent £9247 (inter-quartile range £7751 to £10 853) per 1000 patients on anticoagulants. The marginal effect of a 5% increase in DOAC uptake was associated with a £17.95 (£8.75 to £27.15) increase in total costs, per 1000 patient population.

Conclusion

There were significant differences in the relative uptake of DOACs across practices, with greater costs but no reduction in hospital admissions in those with higher levels of dispensing. Findings indicate that clinical and economic benefits of DOACs identified by clinical trials are not realised in practice.

Non-Vitamin K Antagonist Oral Anticoagulants and the Gastrointestinal Bleeding Risk in Real-World Studies

In the present study, we aimed to provide evidence from high-quality real world studies for a comprehensive and rigorous analysis on the gastrointestinal bleeding (GIB) risk for non-vitamin K antagonist oral anticoagulants (NOACs). We performed a systematic search of MEDLINE, EMBASE and PUBMED, and of 286 records screened, we included data from 11 high-quality real-world studies, coordinated by independent research groups over the last 3 years, that reported major GIB events in patients given NOACs or vitamin K antagonists for patients with nonvalvular atrial fibrillation. The lowest risk of gastrointestinal bleeding was with apixaban compared with warfarin (hazard ratio (HR) for GIB for apixaban ranging between 0.45 (95% confidence interval (CI) 0.34 to 0.59) and 1.13 (95% CI 0.79 to 1.63)). Apixaban was associated with a lower risk of GI bleeding than dabigatran ((HR ranging between 0.39 (95% CI 0.27 to 0.58) and 0.95 (95% CI 0.65 to 1.18)) or rivaroxaban ((HR ranging between 0.33 (95% CI 0.22 to 0.49) and 0.82 (95% CI 0.62 to 1.08)). The results of our study confirm a low or a similar risk for major GIB between patients receiving apixaban or dabigatran compared with warfarin, and apixaban appears to be associated with the lowest risk of GIB.

Switching warfarin to direct oral anticoagulants in atrial fibrillation: Insights from the NCDR PINNACLE registry

BACKGROUND

Previous studies examining the use of direct oral anticoagulants (DOACs) in atrial fibrillation (AF) have largely focused on patients newly initiating therapy. Little is known about the prevalence/patterns of switching to DOACs among AF patients initially treated with warfarin.

HYPOTHESIS

To examine patterns of anticoagulation among patients chronically managed with warfarin upon the availability of DOACs and identify patient/practice-level factors associated with switching from chronic warfarin therapy to a DOAC.

METHODS

Prospective cohort study of AF patients in the NCDR PINNACLE registry prescribed warfarin between May 1, 2008 and May 1, 2015. Patients were followed at least 1 year (median length of follow-up 375 days, IQR 154-375) through May 1, 2016 and stratified as follows: continued warfarin, switched to DOAC, or discontinued anticoagulation. To identify significant predictors of switching, a three-level multivariable hierarchical regression was developed.

RESULTS

Among 383 008 AF patients initially prescribed warfarin, 16.3% (n = 62 620) switched to DOACs, 68.8% (n = 263 609) continued warfarin, and 14.8% (n = 56 779) discontinued anticoagulation. Among those switched, 37.6% received dabigatran, 37.0% rivaroxaban, 24.4% apixaban, and 1.0% edoxaban. Switched patients were more likely to be younger, women, white, and have private insurance (all P < .001). Switching was less likely with increased stroke risk (OR, 0.92; 95%CI, 0.91-0.93 per 1-point increase CHA₂ DS₂ -VASc), but more likely with increased bleeding risk (OR, 1.12; 95%CI, 1.10-1.13 per 1-point increase HAS-BLED). There was substantial variation at the practice-level (MOR, 2.33; 95%CI, 2.12-2.58) and among providers within the same practice (MOR, 1.46; 95%CI, 1.43-1.49).

CONCLUSIONS

Among AF patients treated with warfarin between October 1, 2010 and May 1, 2016, one in six were switched to DOACs, with differences across sociodemographic/clinical characteristics and substantial practice-level variation. In the context of current guidelines which favor DOACs over warfarin, these findings help benchmark performance and identify areas of improvement.

Pattern and Impact of Off-label Underdosing of Non-Vitamin K Antagonist Oral Anticoagulants in Patients With Atrial Fibrillation Who are Indicated for Standard Dosing

With safety concerns about increasing bleeding, off-label underdosing of non-vitamin K antagonist anticoagulants (NOACs) is common in East Asian patients with atrial fibrillation (AF). We tried to investigate the pattern of NOAC underdosing and associated clinical outcomes in patients with AF who are indicated for standard dosing. Using the Korean National Health Insurance Service database, we evaluated 16,568 patients with a new prescription of NOAC who are indicated for standard NOAC dosing and compared 4,536 patients with warfarin with respect to thromboembolic events (ischemic stroke or systemic embolization), all-cause mortality and major bleeding. Of the 16,568 patients indicated for standard NOAC dosing, 8,549 (51.9%) received off-label underdosing (50.6% rivaroxaban, 53.0% apixaban). During a median follow up of 15.0 months, as compared with warfarin, underdosing of rivaroxaban was associated with lower risks of major thromboembolic events (hazard ratio [HR]: 0.53; 95% confidence interval [CI]: 0.41 to 0.69) and all-cause mortality (HR 0.57, 95% CI: 0.41 to 0.82), and a similar risk of major bleeding (HR 1.10, 95% CI: 0.82 to 1.46). However, underdosing of apixaban was associated with similar risks of major thromboembolic events (HR: 0.90; 95% CI: 0.70 to 1.16), all-cause mortality (HR 0.94, 95 CI: 0.71 to 1.24) and major bleeding (HR 0.84, 95% CI: 0.61 to 1.17). In conclusion, in this Korean population with AF who are indicated for standard NOAC dosing, off-label underdosing is common and its clinical benefit over warfarin was inconsistent according to types of NOAC. Notably, apixaban underdosing provides no benefit in effectiveness compared with warfarin.

The problem of underdosing with direct-acting oral anticoagulants in elderly patients with nonvalvular atrial fibrillation

Unless contraindicated, anticoagulant therapy should be prescribed to elderly patients with atrial fibrillation. Direct-acting oral anticoagulants (DOACs) are superior to vitamin K antagonists for preventing stroke. This, together with their higher net clinical benefit, makes DOACs the treatment of choice in this population. However, due to the concerns about bleeding and the need for dose adjustment based on clinical variables, underdosing of DOACs is common and the risk of stroke high. Drugs with more easily adjusted doses are likely associated with a lower risk of dosing errors and, therefore, a greater protective effect. Correct dosing can ensure a maximal net benefit of DOACs in elderly patients with atrial fibrillation.

Comparative effectiveness and safety of oral anticoagulants for atrial fibrillation: A retrospective cohort study

Oral anticoagulants (OACs) are high-priority medications, frequently used with clinically important benefit and serious harm. Our objective was to compare the safety and effectiveness of direct-acting oral anticoagulants (DOACs) versus warfarin in a population where anticoagulation management and DOACs were readily available. A retrospective cohort study of all adults living in British Columbia with a diagnosis of atrial fibrillation and a first prescription for an OAC was conducted. Co-primary outcomes were ischemic stroke and systemic embolism, and major bleeding. Secondary outcomes included a net clinical outcome composite and analysis of discontinuation, switching, and key subgroups. We estimated the effects of treatment using time-to-event models with high-dimensional propensity score adjustment to control confounding. After adjustment for prescribing bias, a cohort (n = 20,113, 43.8% female, mean age 72.4 years) with a mean follow-up of 18.1 months showed that patients taking warfarin tended to be poorer, sicker, and less likely to have a cardiologist prescriber. Outcome event rates were not significantly different for DOACs compared to warfarin [adjusted rate ratio of 1.15 (0.91, 1.46) for systemic embolism, 0.94 (0.82, 1.08) for major bleeding, and 0.98 (0.90, 1.06) for net clinical outcome]. Only the effect of age on net clinical outcome met our strict criteria for predicting which group might be superior. Switch of drug class was associated with increased risk of events (p < 0.003). In this population, we found no difference in important clinical outcomes between warfarin and DOACs. Switching compared to not switching was associated with harm.

Patient self-management of oral anticoagulation with vitamin K antagonists in everyday practice: clinical outcomes in a single centre cohort after long-term follow-up

Background

Patient self-management (PSM) of vitamin K antagonists (VKA) seems a very promising model of care for oral anticoagulation in terms of efficacy and safety. In comparison with other management models of VKA therapy, the number of scientific publications supporting the advantages of PSM is more limited. Currently, most of the scarce information comes from randomized clinical trials. Moreover, a small number of studies have assessed PSM of VKA therapy in real life conditions.

Methods

We analyzed clinical outcomes of 927 patients in a single center (6018.6 patient-years of follow-up). Recruitment took place between 2002 and 2017. All patients followed a structured training program, conducted by specialized nurses.

Results

Fifty percent of individuals had a mechanical heart valve (MHV), 23% suffered from recurrent venous thromboembolism (VTE) or high-risk thrombophilia, and 13% received VKA therapy because of atrial fibrillation (AF). Median follow-up was 6.5 years (range 0.1–15.97 years), median age was 58.1 years (IQR 48–65.9) and 46.5% were women. The incidence of major complications (either hemorrhagic or thromboembolic) was 1.87% patient-years (pt-ys) with a 95% CI of 1.54–2.27. The incidence of major thromboembolic events was 0.86% pt-ys (95% CI 0.64–1.13) and that of major hemorrhagic events was 1.01% pt-ys (95% CI 0.77–1.31). The incidence of intracranial bleeding was 0.22% pt-ys (95% CI 0.12–0.38). In terms of clinical indication for VKA therapy, the incidence of total major complications was 2.4% pt-ys, 2.0% pt-ys, 0.9% pt-ys and 1.34% pt-ys for MHV, AF, VTE and other (including valvulopathies and myocardiopathies), respectively. Clinical outcomes were worse in patients with multiple comorbidities, previous major complications during conventional VKA therapy, and in older individuals. The percentage of time in therapeutic range (TTR) was available in 861 (93%) patients. Overall, the mean (SD) of TTR was 63.6 ± 13.4%, being higher in men (66.2 ± 13.1%) than women (60.6 ± 13.2%), p < 0.05.

Conclusions

In terms of clinically relevant outcomes (incidence of major complications and mortality), PSM in real life setting seems to be a very good alternative in properly trained patients.

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.

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.

Direct Anticoagulants Versus Vitamin K Antagonists in Patients Aged 80 Years or Older With Atrial Fibrillation in a "Real-world" Nationwide Registry: Insights From the FANTASIIA Study

OBJECTIVE

To describe major events at follow up in octogenarian patients with atrial fibrillation (AF) according to anticoagulant treatment: direct oral anticoagulants (DOACs) versus vitamin K antagonists (VKAs).

METHODS

A total of 578 anticoagulated patients aged ≥80 years with AF were included in a prospective, observational, multicenter study. Basal features, embolic events (stroke and systemic embolism), severe bleedings, and all-cause mortality at follow up were investigated according to the anticoagulant treatment received.

RESULTS

Mean age was 84.0 ± 3.4 years, 56% were women. Direct oral anticoagulants were prescribed to 123 (21.3%) patients. Compared with 455 (78.7%) patients treated with VKAs, those treated with DOACs presented a lower frequency of permanent AF (52.9% vs 61.6%, P = .01), cancer history (4.9% vs 10.9%, P = .046), renal failure (21.1% vs 32.2%, P = .02), and left ventricular dysfunction (2.4% vs 8.0%, P = .03); and higher frequency of previous stroke (26.0% vs 16.6%, P = .02) and previous major bleeding (8.1% vs 3.6%, P = .03). There were no significant differences in Charlson, CHA2DS2VASc, nor HAS-BLED scores. At 3-year follow up, rates of embolic events, severe bleedings, and all-cause death (per 100 patients-year) were similar in both groups (DOACs vs VKAs): 0.34 vs 1.35 (P = .15), 3.45 vs 4.41 (P = .48), and 8.2 vs 11.0 (P = .18), respectively, without significant differences after multivariate analysis (hazard ratio [HR]: 0.25, 95% confidence interval [CI]: 0.03-1.93, P = .19; HR: 0.88, 95% CI: 0.44-1.76, P = .72 and HR: 0.84, 95% CI: 0.53-1.33, P = .46, respectively).

CONCLUSION

In this "real-world" registry, the differences in major events rates in octogenarians with AF were not statistically significant in those treated with DOACs versus VKAs.

A consultant-led anticoagulation review of all patients in one clinical commissioning group to prevent atrial fibrillation related stroke

OBJECTIVE

Ensuring patients with Atrial fibrillation (AF) are appropriately anticoagulated across NHS Bedfordshire Clinical Commissioning Group (BCCG) with the primary goal of reducing AF-related strokes.

METHODS

With Inspira Health, BCCG adopted the Primary Care Atrial Fibrillation (PCAF) Service which is led by Consultant Cardiologists. PCAF uses retrospective clinical audit to identify patients who require prospective face-to-face review on the need for anticoagulation.

RESULTS

34 GP practices participated covering a 376 311 population (80% of BCCG). 12 573 patients' medical records were audited. The initial AF register was 7301 patients (AF prevalence 1.9%) and an additional 265 patients were identified through AF casefinder resulting in an AF prevalence of 2.0%. From 7566 patients with AF, 5831 were already on anticoagulants (77.1%), with 50.5% (n = 2947) on VKA medications and 49.5% (n = 2884) on direct oral anticoagulants (DOACs). Of the DOAC patients, 595 (20.6%) required dosage review or up to date blood tests. Case notes were reviewed for 1735 patients not on anticoagulation, with 901 (51.9%) patients deemed not eligible for anticoagulation. This left 834 (48.1%) patients who were eligible for, but not on, anticoagulation. A further 407 (13.8%) patients currently taking VKA medications were deemed sup-optimal with regards to INR control with TTR < 65%. In total 1241 patients were invited for review by a Consultant Cardiologist at their local GP practice, with an attendance rate of 90%. From all face to face and virtual consultations, 908 patients had anticoagulants prescribed, changed, management of INRs improved or were in the process of being anticoagulated at the time of follow-up. From this we would expect 36.3 AF related strokes prevented and a cost saving to the NHS of £470 200 per year.

CONCLUSION

Through comprehensive audit, BCCG have been able to ensure that patients with AF are appropriately anticoagulated in 80% of their catchment population. This has improved anticoagulation to prevent AF-related stroke.

Risk of Major Gastrointestinal Bleeding With New vs Conventional Oral Anticoagulants: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

There is controversy over whether use of non-vitamin K antagonist oral anticoagulants (NOACs) associates with increased risk of major gastrointestinal bleeding (GIB) compared with conventional therapies (such as vitamin K antagonists or anti-platelet agents). We performed a systematic review and meta-analysis of data from randomized controlled trials and high-quality real-world studies.

METHODS

We performed a systematic search of the MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov Website databases (through Oct 12, 2018) for randomized controlled trials and high-quality real-world studies that reported major GIB events in patients given NOACs or conventional therapy. Relative risks (RRs) for randomized controlled trials and adjusted hazard ratios (aHRs) for real-world studies were calculated separately using random-effects models.

RESULTS

We analyzed data from 43 randomized controlled trials (183,752 patients) and 41 real-world studies (1,879,428 patients). The pooled major rates of GIB for patients on NOACs (1.19%) vs conventional treatment (0.92%) did not differ significantly (RR from randomized controlled trials, 1.09; 95% CI, 0.91-1.31 and aHR from real-world studies, 1.02; 95% CI, 0.94-1.10; P_interaction=.52). Rivaroxaban, but not other NOACs, was associated with an increased risk for major GIB (RR from randomized controlled trials, 1.39; 95% CI, 1.17-1.65 and aHR from real-world studies, 1.14; 95% CI, 1.04-1.23; P_interaction = .06). Analyses of subgroups, such as patients with different indications, dosage, or follow-up time, did not significantly affect results. Meta-regression analysis failed to detect any potential confounding to impact the primacy outcome.

CONCLUSIONS

In a systematic review and meta-analysis of data from randomized controlled trials and real-world studies, we confirmed that there is no significant difference in risk of major GIB between patients receiving NOACs vs conventional treatment. Rivaroxaban users had a 39% increase in risk for major GIB.

Propensity score matching and inverse probability of treatment weighting to address confounding by indication in comparative effectiveness research of oral anticoagulants

After decades of warfarin being the only oral anticoagulant (OAC) widely available for stroke prevention in atrial fibrillation, four direct OACs (apixaban, dabigatran, edoxaban and rivaroxaban) were approved after demonstrating noninferior efficacy and safety versus warfarin in randomized controlled trials. Comparative effectiveness research of OACs based on real-world data provides complementary information to randomized controlled trials. Propensity score matching and inverse probability of treatment weighting are increasingly popular methods used to address confounding by indication potentially arising in comparative effectiveness research due to a lack of randomization in treatment assignment. This review describes the fundamentals of propensity score matching and inverse probability of treatment weighting, appraises differences between them and presents applied examples to elevate understanding of these methods within the atrial fibrillation field.

All-Cause Mortality and Cardiovascular Outcomes With Non-Vitamin K Oral Anticoagulants Versus Warfarin in Patients With Heart Failure in the Food and Drug Administration Adverse Event Reporting System

BACKGROUND

Many patients with heart failure (HF) are treated with warfarin or non-vitamin K oral anticoagulants (NOACs). Randomized outcome-driven comparisons of different anticoagulant strategies in HF are lacking. Data from international, government-mandated registries may be useful in understanding the real-life use of various anticoagulants and how they are linked to outcomes.

STUDY QUESTION

To assess 2015 annual all-cause mortality, myocardial infarction, and stroke rates co-reported for warfarin and NOACs in subjects with and without HF in the US Food and Drug Administration Adverse Event Reporting System (FAERS) database.

STUDY DESIGN

We extracted and examined outcome cases in subjects with HF and on warfarin, dabigatran, rivaroxaban, apixaban, or edoxaban and stratified these according to anticoagulants.

MEASURES AND OUTCOMES

Annual all-cause mortality, myocardial infarction, and stroke in FAERS.

ANALYSIS METHOD

Odds ratio (OR) and χ(Equation is included in full-text article.)for oral anticoagulants from FAERS with and without HF among complete primary reports issued in 2015.

RESULTS

FAERS reported 137,026 HF cases, with death co-reported in 42,942 (31.3%). In total, 11,278 (8.2%) HF patients were treated with anticoagulants, with more prescribed warfarin (n = 8260) than all NOACs combined (n = 3018). Very few reports for edoxaban were available. Warfarin consistently displayed a signal for excess adverse events compared to NOACs: OR (95% confidence interval) for the composite of mortality, myocardial infarction, and stroke were 1.91 (1.76-2.07) versus apixaban, 1.92 (1.81-2.03) versus dabigatran, 4.09 (3.38-4.37) versus rivaroxaban, and 2.64 (2.53-2.76) versus all NOACs combined (all P < 0.001). Warfarin, compared to all NOACs combined, demonstrated higher rates of all-cause mortality [OR = 2.69 (95% confidence interval, 2.49-2.90)], myocardial infarction [5.30 (4.17-6.74)], stroke [OR = 8.85 (6.61-11.84)], and ischemic stroke [OR = 12.73 (8.87-18.27); all P < 0.001].

CONCLUSIONS

Annual 2015 FAERS profiles in HF patients reveal that warfarin was numerically dominant. Warfarin was associated with higher risk of death, myocardial infarction, and stroke compared to NOACs. These observational data provide real-world insight into a potential safety benefit of NOACs over warfarin in the setting of HF.

[Effectiveness, safety and costs of stroke prevention in non-valvular auricular fibrillation. Study of cohorts matched by Propensity score]

OBJECTIVE

To analyze the use, effectiveness, safety and costs of stroke prevention in non-valvular atrial fibrillation (AF) in patients initiating treatment with dabigatran or vitamin K antagonists (VKA).

SETTING

Primary Care (PC) at the Catalan Health Institute (ICS) in Catalonia, during 2011-2013.

PARTICIPANTS

Patients attended in ICS PC centres with a registered diagnosis of AF who initiate dabigatran or VKA.

INTERVENTIONS

Not applicable MAIN MEASUREMENTS: Number of prescriptions and reimbursements of dabigatran and VKA, incidence of stroke and haemorrhages, incidence of mortatlity, number of sickness leave, and costs associated to all the previous variables.

RESULTS

14,930 patients were included; 94.6% initiated VKA and 5.4%, dabigatran. Dabigatran patients were younger and with less comorbidity. There were no statistically significant differences between VKA and dabigatran in the risk of stroke, haemorrhages or death. The costs associated to AF management were higher for PC visits in the VKA group, and higher for laboratory and pharmacy in the dabigatran group, although overall costs were not statistically different.

CONCLUSIONS

Most patients initiated VKA. We found no differences between VKA and dabigatran in the risk of stroke, haemorrhages or mortality.

Effectiveness and Safety of Direct Oral Anticoagulants in Relation to Temporal Changes in Their Use

Background:

Since the direct oral anticoagulants (DOAC) were introduced, oral anticoagulant (OAC) prescription patterns have rapidly changed in patients with atrial fibrillation (AF). We aimed to evaluate the evolving trends of OAC use in a large nationwide cohort and specifically examine the changes in patient profiles treated with warfarin or DOAC and whether the time trends in OAC use affected clinical outcomes.

Methods and Results:

Using the Korean Health Insurance Review and Assessment database, we divided OAC naive patients with AF into 3 groups according to the enrollment period between January 2015 and December 2017 (n=35 353 in cohort 1, n=36 631 in cohort 2, and n=44 819 in cohort 3). DOAC use increased from 59% to 89%, whereas warfarin use has decreased from 41% to 11% during the study period. Patients treated with warfarin were increasingly younger from cohort 1 to cohort 3 (mean age 68–65 years, P <0.001) with lower mean CHA 2 DS 2 -VASc scores (3.3–2.9, P <0.001), whereas those with DOAC did not show a significant difference in clinical characteristics over the study period. Warfarin group had improved clinical outcomes over time, reflecting dynamic changes in patient characteristics. Compared with warfarin group, unadjusted hazard ratios of composite outcome for DOAC group have changed over time (hazard ratio 0.77 [95% CI, 0.69–0.85] in cohort 1, hazard ratio 0.84 [95% CI, 0.73–0.97] in cohort 2, and hazard ratio 1.00 [95% CI, 0.78–1.25] in cohort 3). After propensity score weighting between warfarin and DOAC groups in each cohort, DOAC showed consistently lower risks of the composite outcome by approximately 23% to 25% compared with warfarin across 3 different periods.

Conclusions:

In contemporary clinical practice, OAC prescription patterns and characteristics of patients treated warfarin or DOAC have dynamically changed. Despite these changes, DOAC showed a consistent better net clinical benefit compared with warfarin across different periods.

Anticoagulants' Safety and Effectiveness in General Practice: A Nationwide Prospective Cohort Study

PURPOSE

Most real-world studies on anticoagulants have been based on health insurance databases or performed in secondary care. The aim of this study was to compare safety and effectiveness between patients treated with vitamin K antagonists (VKAs) and patients treated with direct oral anticoagulants (DOACs) in a general practice setting.

METHODS

The CACAO study (Comparison of Accidents and their Circumstances with Oral Anticoagulants) is a multicenter prospective cohort study conducted among ambulatory patients taking an oral anticoagulant. Participants were patients from the study's cross-sectional phase receiving oral anticoagulants because of nonvalvular atrial fibrillation, for secondary prevention of venous thromboembolism, or both. They were followed as usual for 1 year by their general practitioners, who collected data on changes in therapy, thromboembolic events, bleeding, and deaths. All events were adjudicated by an independent committee. We used a propensity score and a Cox regression model to derive hazard ratios.

RESULTS

Between April and December 2014, a total of 3,082 patients were included. At 1 year, 42 patients (1.7%) had experienced an arterial or venous event; 151 (6.1%) had experienced bleeding, including 47 (1.9%) who experienced major bleeding; and 105 (4.1%) had died. There was no significant difference between the VKA and DOAC groups regarding arterial or venous events, or major bleeding. The VKA group had a lower risk of overall bleeding (hazard ratio = 0.65; 95% CI, 0.43-0.98) but twice the risk of death (hazard ratio = 1.98; 95% CI, 1.15-3.42).

CONCLUSIONS

VKAs and DOACs had fairly similar safety and effectiveness in general practice. The substantially higher incidence of deaths with VKAs is consistent with known data from health insurance databases and calls for further research to understand its cause.

Effects of body mass index on the safety and effectiveness of direct oral anticoagulants: a retrospective review

BACKGROUND

The International Society on Thrombosis and Haemostasis recommends avoiding the use of direct oral anticoagulants (DOACs) in patients with a body mass index (BMI) greater than 40 kg/m² or weight greater than 120 kg.

HYPOTHESIS

Higher BMI is associated with altered pharmacokinetics which may affect the safety and effectiveness for DOACs.

METHODS

Data were collected on 3458 patients taking a DOAC prior to admission to a Midwestern health system between February 2013 and August 2016. Of these, 43 patients had a thrombotic event and 70 patients had an overt bleeding event. Patients were stratified among the following three BMI groups: BMI < 30 kg/m², BMI 30-40 kg/m², and BMI > 40 kg/m².

RESULTS

There was no statistically significant difference between BMI groups for thrombotic events (p = 0.598) or for overt bleeding events (p = 0.065). The BMI < 30 kg/m² had the highest occurrence rate of bleeding events. It was observed that bleeding occurrence decreased as the BMI groups increased. The BMI > 40 kg/m² group had the lowest risk of bleeding events, and was the only group to have a higher occurrence rate of thrombotic events compared to bleeding events.

CONCLUSIONS

Among patients admitted to a single health system on DOAC therapy over a three-and-a-half-year period, obesity did not significantly correlate with thrombotic or overt bleeding complications. This study is limited as a single health system study with low overall event rates. A preliminary finding of this study showed a trend towards decreased bleeding frequency as BMI increased.

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

Non–vitamin K antagonist anticoagulants (NOACs) have been used to prevent thromboembolism in patients with atrial fibrillation (AF) and shown favorable clinical outcomes compared with warfarin. However, off-label use of NOACs is frequent in practice, and its clinical results are inconsistent. Furthermore, the quality of anticoagulation available with warfarin is often suboptimal and even inaccurate in real-world data. We have therefore compared the effectiveness and safety of off-label use of NOACs with those of warfarin whose anticoagulant intensity was accurately estimated. We retrospectively analyzed data from 2,659 and 3,733 AF patients at a tertiary referral center who were prescribed warfarin and NOACs, respectively, between 2013 and 2018. NOACs were used at off-label doses in 27% of the NOAC patients. After adjusting for significant covariates, underdosed NOAC (off-label use of the reduced dose) was associated with a 2.5-times increased risk of thromboembolism compared with warfarin, and overdosed NOAC (off-label use of the standard dose) showed no significant difference in either thromboembolism or major bleeding compared with warfarin. Well-controlled warfarin (TTR ≥ 60%) reduced both thromboembolism and bleeding events. In conclusion, the effectiveness of NOACs was decreased by off-label use of the reduced dose.

Comparative Real-Life Effectiveness and Safety of Dabigatran or Rivaroxaban vs. Vitamin K Antagonists: A High-Dimensional Propensity Score Matched New Users Cohort Study in the French National Healthcare Data System SNDS

BACKGROUND

Clinical trials have indicated that the direct-acting oral anticoagulants dabigatran and rivaroxaban have better risk/benefit profiles than do vitamin K antagonists (VKAs) for stroke prevention in non-valvular atrial fibrillation (NVAF).

OBJECTIVE

Our objective was to compare the 1-year real-life risk of major clinical events with dabigatran or rivaroxaban versus VKAs for NVAF.

METHODS

This was a high-dimensional propensity score (hdPS)-matched cohort study of new users of dabigatran, rivaroxaban or VKAs for NVAF in the French national healthcare systems database in 2013 followed-up for 1 year [22]. Hazard ratios (HRs) with 95% confidence intervals (CIs) for clinical events and death were determined during exposure.

RESULTS

In 2013, a total of 103,101 new anticoagulant users had definite NVAF: 44,653 VKA, 27,060 dabigatran, and 31,388 rivaroxaban. In matched populations, HRs were as follows for dabigatran versus VKAs (20,489 per group): stroke and systemic embolism (SSE) 0.75 (95% CI 0.63-0.88), clinically relevant bleeding (CRB) 0.58 (95% CI 0.51-0.66), hemorrhagic stroke (HS) 0.22 (95% CI 0.14-0.36), gastrointestinal bleeding (GIB) 0.98 (95% CI 0.80-1.19), acute coronary syndrome (ACS) 0.79 (95% CI 0.65-0.95), death 0.74 (95% CI 0.67-0.82), composite (any of the above) 0.71 (95% CI 0.66-0.76). For matched rivaroxaban versus VKA (23,053 per group) HRs were as follows: SSE 0.98 (95% CI 0.85-1.14), CRB 0.83 (95% CI 0.75-0.92), HS 0.65 (95% CI 0.49-0.87), GIB 1.08 (95% CI 0.90-1.30), ACS 0.84 (95% CI 0.71-1.00), death 0.77 (95% CI 0.71-0.84), composite 0.84 (95% CI 0.79-0.89). Numbers needed to treat to observe one fewer death were 49 ± 0.05 with dabigatran or rivaroxaban versus VKAs.

CONCLUSION

Consistent with results from clinical trials and other observational studies, dabigatran and rivaroxaban were at least as effective and safer than VKAs for the prevention of thromboembolic events in NVAF over 1 year in the French population.

STUDY REGISTRATION

European Medicines Agency EUPAS 13017 (www.encepp.eu) Clinicaltrials.gov id NCT02785354.

Association between hypocalcemia and rivaroxaban in coagulation disorders: a case report

We describe a patient with tertiary hyperparathyroidism with history of three episodes of deep vein thrombosis and on rivaroxaban. The patient underwent a subtotal parathyroidectomy, developing cervical hematoma with airway compression. Therefore, emergency surgical decompression was necessary. Later, on the ninth postoperative day, the serum ionized calcium levels were low. Medical team knowledge about preexisting diseases and their implication in the coagulation state are essential conditions to reduce morbidity and mortality of surgeries. However, no reports were found in literature about the association of hypocalcemia with the use of the new class of anticoagulants, which act as factor X inhibitors (Stuart-Prower factor), predisposing to increased bleeding in the immediate postoperative period.

Elderly Bleeding Risk of Direct Oral Anticoagulants in Nonvalvular Atrial Fibrillation: A Systematic Review and Meta-Analysis of Cohort Studies

Introduction

The 2014 American Heart Association (AHA)/American College of Cardiology (ACC)/Heart Rhythm Society (HRS) guidelines recommend anticoagulation to reduce clot formation and the risk of thromboembolic events in patients with atrial fibrillation but does not specify guidelines for the elderly population. Direct oral anticoagulants (DOACs) are newer US FDA-approved alternatives to warfarin and include dabigatran, rivaroxaban, apixaban and edoxaban. The efficacy of DOACs is heavily researched, but few studies have evaluated their bleeding risk.

Objectives

This systematic review and meta-analysis investigates which DOAC has the lowest bleeding risk in elderly patients with nonvalvular atrial fibrillation (NVAF).

Methods

CINAHL and MEDLINE databases were searched using specific keywords, and 244 results were identified and screened. Inclusion criteria required a major bleeding event requiring hospitalization as an outcome and excluded patients with severe renal failure. Articles that met inclusion criteria were assessed for risk of bias using the Cochrane Tool to Assess Risk of Bias in Cohort Studies. Review Manager (version 5) was used to perform the random-effects model meta-analysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. P < 0.05 was considered statistically significant.

Results

Six articles met inclusion criteria and encompassed 446,042 patients in total. Apixaban and dabigatran had statistically significant risk reductions compared with warfarin, whereas rivaroxaban did not (HR 0.60 [95% CI 0.52–0.69], p < 0.00001; HR 0.79 [95% CI 0.70–0.90], p = 0.0005; HR 1.03 [95% CI 0.86–1.22], p = 0.77, respectively.) Data regarding edoxaban were limited and thus not included in the analysis.

Conclusion

Apixaban and dabigatran have a significantly decreased major bleeding risk (40 and 21%, respectively) compared with warfarin. There was no statistical difference in bleeding risk between rivaroxaban and warfarin. Head-to-head prospective randomized controlled trials are required to assess the true bleeding risk of each DOAC.

Non-vitamin K antagonist oral anticoagulation agents in patients with atrial fibrillation: Insights from Italian monitoring registries

Background

Atrial fibrillation (AF) is the most common cardiac arrhythmia associated with an increased risk of stroke and thromboembolism. Anticoagulation with Vitamin K antagonists (VKAs) or with novel oral anti-coagulants (NOACs) represents the cornerstone of the pharmacological treatment to reduce the risk of thromboembolism. This study aims to provide real-world data from a whole large European country about NOAC use in "non-valvular atrial fibrillation" (NVAF).

Methods

We analysed the Italian Medicines Agency (AIFA) monitoring registries collecting data of a nationwide cohort of patients with "NVAF" treated with NOACs. Using logistic regression analysis, baseline characteristics and treatment discontinuation information were compared among initiators of the 4 NOACs.

Results

In the reference period, the NOAC database collected data for 683,172 patients. The median age was 78 years with 19.5% aged 85 or older. Overall, the treatments were in accordance with guidelines. About 1/3 of patients switched from a prior VKA treatment; in the 72.3% of cases, these patients had a labile International Normalized Ratio (INR) at first prescription. The most prescribed NOAC was rivaroxaban, followed by apixaban, dabigatran and edoxaban.

Conclusions

This study is the largest European real-world study ever published on NOACs. It includes all Italian patients treated with NOACs since 2013 accounting for about 1/3 of subjects with AF. The enrolled population consisted of very elderly patients, at high risk of ischemic adverse events. The AIFA registries are consolidated tools that guarantee the appropriateness of prescription and provide important information for the governance of National Health System by collecting real-world data.

Practical use of Direct Oral Anti Coagulants (DOACs) in the older persons with atrial fibrillation

Direct Oral Anticoagulants (DOACs) consistently demonstrated a greater net clinical benefit compared to Vitamin K Antagonists (VKAs) also in persons aged 75 years and over, who account for the largest proportion of AF patients; however, major uncertainties in DOACs prescription have to do with this age group. In this review, persistent uncertainties and implications of frailty and geriatric syndromes on DOACs prescription, and practical use of DOACs in real-world older persons, and will be discussed.

Effectiveness and safety of direct oral anticoagulants in atrial fibrillation patients switched from vitamin K antagonists: A systematic review and meta-analysis

A substantial proportion of atrial fibrillation patients initiating direct oral anticoagulants (DOAC) are vitamin K antagonists (VKA)-experienced, for example switchers from VKA to DOAC. With this study, we aimed to summarize available evidence on the effectiveness and safety of DOAC vs VKA in real-life VKA-experienced atrial fibrillation patients. We searched EMBASE, MEDLINE and Cochrane Library systematically for English-language studies indexed any time before October 2018. We included studies of VKA-experienced atrial fibrillation patients initiating DOAC therapy, with continued VKA therapy as comparator. Outcomes included arterial thromboembolism and bleeding. When appropriate, meta-analysis was performed by calculating pooled, weighted and adjusted hazard ratios (aHR) with 95% confidence intervals (CI). Eight cohort studies comparing VKA-experienced DOAC (dabigatran or rivaroxaban) users with continued VKA users were included. When comparing DOAC to VKA, an increased risk of ischaemic stroke and myocardial infarction was found for dabigatran (pooled aHR of 1.61 [95% CI 1.19-2.19, I2  = 65%] and 1.29 [95% CI 1.10-1.52, I2  = 0%], respectively), but not for rivaroxaban. The use of dabigatran in VKA-experienced users was associated with an increased risk of gastrointestinal bleeding (pooled aHR 1.63 [95% CI 1.36-1.94, I2  = 30%]), but a decreased risk of intracranial bleeding (pooled aHR 0.45 [95% CI 0.32-0.64, I2  = 0%]). In conclusion, the use of dabigatran in prior VKA users in clinical practice was associated with a slightly increased risk of arterial thromboembolism and gastrointestinal bleeding, but a decreased risk of intracranial bleeding. Importantly, observational studies of real-life VKA-experienced oral anticoagulant users may be confounded by the reason for switching.

Effectiveness and Safety of Direct Oral Anticoagulant for Secondary Prevention in Asians with Atrial Fibrillation

We investigated the effectiveness and safety of direct oral anticoagulants (DOACs) for secondary prevention in patients with atrial fibrillation (AF), particularly focusing on subgroups of patients with severe, disabling, and recent stroke. Using the Korean National Health Insurance Service claims database between January 2010 and April 2018, we selected OAC-naïve patients with non-valvular AF and a history of stroke. Cumulative risks for recurrent stroke, major bleeding, composite outcome (recurrent stroke + major bleeding), and mortality were compared between DOAC and warfarin groups. Among 61,568 patients, 28,839 and 32,729 received warfarin and DOACs, respectively. Compared with warfarin, DOACs were associated with lower risks of recurrent stroke (hazard ratio (HR) 0.67, 95% confidence interval (CI) 0.62-0.72), major bleeding (HR 0.73, 95% CI 0.66-0.80), composite outcome (HR 0.69, 95% CI 0.65-0.73), and mortality. DOAC use resulted in a consistent trend of improved outcomes in the subgroups of patients with severe, disabling, and recent stroke. In conclusion, DOACs were associated with lower risks of recurrent stroke, major bleeding, composite clinical outcomes, and mortality in patients with AF and a history of stroke. These results were consistent across all types of DOACs and subgroups of patients with severe, disabling, and recent stroke.

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

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

Non-vitamin K antagonist oral anticoagulants and warfarin in atrial fibrillation patients with concomitant peripheral artery disease

AIMS 

To investigate the effectiveness, safety, and outcomes of lower limb events for non-vitamin K antagonist oral anticoagulants (NOACs) vs. warfarin among atrial fibrillation (AF) patients with concomitant peripheral artery disease (PAD).

METHODS AND RESULTS

In this nationwide retrospective cohort study collected from Taiwan National Health Insurance Research Database, a total of 5768 and 2034 consecutive AF patients with PAD patients taking NOACs or warfarin were identified from 1 June 2012 to 31 December 2017, respectively. We used propensity score stabilized weighting to balance covariates across study groups. In the cohort, there were 89% patients were taking low-dose NOAC (dabigatran 110 mg twice daily, rivaroxaban 10-15 mg daily, apixaban 2.5 mg twice daily, or edoxaban 30 mg daily). Non-vitamin K antagonist oral anticoagulant was associated with a comparable risk of ischaemic stroke, and a lower risk of acute myocardial infarction [hazard ratio (HR): 0.61, 95% confidence interval (CI): 0.42-0.87; P = 0.007], lower extremity thromboembolism (HR: 0.56, 95% CI: 0.44-0.72; P < 0.0001), revascularization procedure (HR: 0.58, 95% CI: 0.47-0.72; P < 0.0001), lower limb amputation (HR: 0.32, 95% CI: 0.23-0.46; P < 0.0001), and all major bleeding (HR: 0.64, 95% CI: 0.50-0.80; P = 0.0001) than warfarin after weighting. The advantage of NOACs over warfarin persisted in high-risk subgroups including patients of ≥75 years of age, diabetes, renal impairment, or use of concomitant antiplatelet agent.

CONCLUSION 

This population-based study indicated that NOACs were associated with a comparable risk of ischaemic stroke, and a significantly lower risk of major adverse limb events and major bleeding than warfarin among AF patients with concomitant PAD. Therefore, thromboprophylaxis with NOACs may be considered for such patients.

Effectiveness and safety of edoxaban in patients with atrial fibrillation: data from the Danish Nationwide Cohort

AIMS 

Edoxaban treatment for stroke prevention in atrial fibrillation (AF) has mainly been investigated in randomized controlled trials, and data reflecting clinical practice are limited. We ascertained the clinical effectiveness and safety of edoxaban 30 and 60 mg once daily among Danish patients with AF.

METHODS AND RESULTS 

This was an observational study based on Danish nationwide registries collecting information for administrative purposes. From June 2016 through November 2018, we identified 3405 patients initiating edoxaban. After exclusions, 2285 AF patients were followed for the effectiveness outcome of thromboembolism (ischaemic stroke and/or systemic embolism) and bleeding outcomes (composite of major bleeding, gastrointestinal bleeding, and intracranial haemorrhage), as well as bleeding requiring hospitalization. Population mean age was 75 years and 43% were female; 643 patients received the 30 mg edoxaban dosage regimen and 1642 initiated 60 mg edoxaban. During follow-up, we observed 41 thromboembolic events and 89 bleeding events of which 40 events required hospitalization. Among patients with 30 mg edoxaban, the rate (per 100 person-years) of thromboembolism was 2.07 vs. 1.62 for 60 mg edoxaban. Rates of bleeding were similar for the two dosages at ∼3.85. Bleeding requiring hospitalization occurred at a rate of 1.74 for 30 mg edoxaban and 1.69 with 60 mg edoxaban.

CONCLUSION 

In this nationwide cohort of Caucasian AF patients treated with edoxaban for stroke prevention, the clinical effectiveness and safety were in line with data from the ENGAGE AF-TIMI 48 trial. Studies investigating comparative effectiveness and safety for edoxaban in comparison with other choices of antithrombotic treatment options are needed.

Association of Oral Anticoagulant Type With Risk of Dementia Among Patients With Nonvalvular Atrial Fibrillation

Background

Oral anticoagulants (OACs) in patients with atrial fibrillation (AF), in addition to reducing stroke risk, could also prevent adverse cognitive outcomes. The purpose of this study was to compare the risk of dementia incidence across patients with AF initiating different OACs.

Methods and Results

We identified patients with nonvalvular AF initiating OACs in 2 US healthcare claim databases, MarketScan (2007–2015) and Optum Clinformatics (2009–2015). Dementia, comorbidities, and use of medications were defined on the basis of inpatient and outpatient claims. We performed head‐to‐head comparisons of warfarin, dabigatran, rivaroxaban, and apixaban in propensity score–matched cohorts. We calculated hazard ratios (HRs) and 95% confidence intervals (CIs) of incident dementia for each propensity score–matched cohort and meta‐analyzed database‐specific results. We analyzed 307 099 patients with AF from the MarketScan database and 161 346 from the Optum database, of which 6572 and 4391, respectively, had a diagnosis of incident dementia. The mean follow‐up of each cohort ranged between 0.7 and 2.2 years. Patients initiating direct OACs experienced lower rates of dementia than those initiating warfarin (dabigatran: HR, 0.85; 95% CI, 0.71–1.01; rivaroxaban: HR, 0.85; 95% CI, 0.76–0.94; apixaban: HR, 0.80; 95% CI, 0.65–0.97). There were no differences in rates of dementia comparing direct OAC user groups (dabigatran versus rivaroxaban: HR, 1.02; 95% CI, 0.79–1.32; dabigatran versus apixaban: HR, 0.92; 95% CI, 0.63–1.36; apixaban versus rivaroxaban: HR, 1.01; 95% CI, 0.86–1.19).

Conclusions

Patients with AF initiating direct OACs experienced lower rates of incident dementia than warfarin users. No obvious benefit was observed for any particular direct OAC in relation to dementia rates.

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.

The 2018 European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation

The current manuscript is the second update of the original Practical Guide, published in 2013 [Heidbuchel et al. European Heart Rhythm Association Practical Guide on the use of new oral anticoagulants in patients with non-valvular atrial fibrillation. Europace 2013;15:625-651; Heidbuchel et al. Updated European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist anticoagulants in patients with non-valvular atrial fibrillation. Europace 2015;17:1467-1507]. Non-vitamin K antagonist oral anticoagulants (NOACs) are an alternative for vitamin K antagonists (VKAs) to prevent stroke in patients with atrial fibrillation (AF) and have emerged as the preferred choice, particularly in patients newly started on anticoagulation. Both physicians and patients are becoming more accustomed to the use of these drugs in clinical practice. However, many unresolved questions on how to optimally use these agents in specific clinical situations remain. The European Heart Rhythm Association (EHRA) set out to coordinate a unified way of informing physicians on the use of the different NOACs. A writing group identified 20 topics of concrete clinical scenarios for which practical answers were formulated, based on available evidence. The 20 topics are as follows i.e., (1) Eligibility for NOACs; (2) Practical start-up and follow-up scheme for patients on NOACs; (3) Ensuring adherence to prescribed oral anticoagulant intake; (4) Switching between anticoagulant regimens; (5) Pharmacokinetics and drug-drug interactions of NOACs; (6) NOACs in patients with chronic kidney or advanced liver disease; (7) How to measure the anticoagulant effect of NOACs; (8) NOAC plasma level measurement: rare indications, precautions, and potential pitfalls; (9) How to deal with dosing errors; (10) What to do if there is a (suspected) overdose without bleeding, or a clotting test is indicating a potential risk of bleeding; (11) Management of bleeding under NOAC therapy; (12) Patients undergoing a planned invasive procedure, surgery or ablation; (13) Patients requiring an urgent surgical intervention; (14) Patients with AF and coronary artery disease; (15) Avoiding confusion with NOAC dosing across indications; (16) Cardioversion in a NOAC-treated patient; (17) AF patients presenting with acute stroke while on NOACs; (18) NOACs in special situations; (19) Anticoagulation in AF patients with a malignancy; and (20) Optimizing dose adjustments of VKA. Additional information and downloads of the text and anticoagulation cards in different languages can be found on an EHRA website (www.NOACforAF.eu).

Edoxaban Plus Aspirin vs Dual Antiplatelet Therapy in Endovascular Treatment of Patients With Peripheral Artery Disease: Results of the ePAD Trial

Purpose: To report a randomized study that investigated the safety (risk of major bleeds) and potential efficacy of edoxaban, an oral anticoagulant that targets the major components of arterial thrombi, to prevent loss of patency following endovascular treatment (EVT). Methods: Between February 2012 and June 2014, 203 patients who underwent femoropopliteal EVT were randomized to receive aspirin plus edoxaban or aspirin plus clopidogrel for 3 months in the Edoxaban in Peripheral Arterial Disease (ePAD) study (ClinicalTrials.gov identifier NCT01802775). Randomization assigned 101 patients (mean age 68.0±10.4 years; 67 men) to the edoxaban group and 102 patients (mean age 66.7±8.6 years; 78 men) to the clopidogrel group. The primary safety endpoint was bleeding as classified by the TIMI (Thrombolysis in Myocardial Infarction) criteria and ISTH (International Society of Thrombosis and Hemostasis) criteria; the efficacy endpoint was the rate of restenosis/reocclusion. Results: There were no major or life-threatening bleeding events in the edoxaban group, while there were 2 major and 2 life-threatening bleeding events in the clopidogrel group by the TIMI criteria. By the ISTH classification, there was 1 major and 1 life-threatening bleeding event vs 5 major and 2 life-threatening bleeding events, respectively [relative risk (RR) 0.20, 95% confidence interval (CI) 0.02 to 1.70]. The bleeding risk was not statistically different with either treatment when assessed by TIMI or ISTH. Following 6 months of observation, there was a lower incidence of restenosis/reocclusion with edoxaban compared with clopidogrel (30.9% vs 34.7%; RR 0.89, 95% CI 0.59 to 1.34, p=0.643). Conclusion: These results suggest that patients who have undergone EVT have similar risks for major and life-threatening bleeding events with edoxaban and aspirin compared with clopidogrel and aspirin. The incidence of restenosis/reocclusion events, while not statistically different, was lower with edoxaban and aspirin, but an adequately sized trial will be needed to confirm these findings.

Clinical Characteristics And Health Care Resources In Patients Treated With Oral Anticoagulants: Evidences From Italian Administrative Databases

Objectives

1) To evaluate anticoagulation treatment patterns and health care resource use in adult patients with a discharge diagnosis of non-valvular atrial fibrillation (NVAF) in an Italian real-world setting and 2) to describe the characteristics of NVAF patients in relation to treatment.

Design

A retrospective cohort study in a "real-world" setting.

Setting

Data were analysed by integrating administrative databases that included approximately 2,000,000 individuals assisted by the National Health System from two Italian Local Health Units.

Participants

All adult patients with at least one hospital discharge or ≥2 outpatient visits with a diagnosis code for NVAF from 1/01/2011 to 31/12/2015 were included.

Main outcome measures

Anticoagulation treatment patterns, health care resource use and major bleeding events that occurred during the follow-up period were evaluated.

Results

32,863 NVAF patients were included, of whom 7,831 had at least one prescription of oral anticoagulants. Among them, 6,876 patients were vitamin K antagonists (VKA) users and 955 were non-vitamin K antagonist oral anticoagulant (NOAC) users at index date (ID). During the follow-up period, the use of antiplatelet drugs was higher among VKA-naïve users than the NOAC-naïve users. Among NOAC users, 76.1% showed an adherence level ≥80% during follow-up. The rate of bleeding events resulted higher for VKA patients compared to NOAC patients. The unadjusted incidence rate was 10.46 per 1000 person-year for VKA patients and 4.55 per 1,000 person-years for NOAC patients. The overall annual cost (in term of drugs, hospitalisations and outpatient specialist services) was € 5,156.13 for VKA and € 4,630.57 for NOAC.

Conclusion

This unselected cohort study, on NVAF patients being prescribed oral anticoagulants, highlights that VKA was largely prescribed and the great majority of patients on NOACs were adherent to treatment. Most of the OAC patients still received antiplatelet agents in combination, and in NOAC patients, we registered a lower number of bleeding events compared with VKA.

Mortality risk in atrial fibrillation: the role of aspirin, vitamin K and non-vitamin K antagonists

Background As an alternative to vitamin K antagonist and low-dose aspirin (< 325 mg), non-vitamin K oral anticoagulants are available for the prevention of stroke in patients with atrial fibrillation. However, the mortality risk associated with these drugs in daily practice remains unclear. Objective To evaluate the risk of all-cause mortality associated with non-Vitamin K antagonist oral anticoagulants, vitamin K antagonists or aspirin in patients with atrial fibrillation. Setting A cohort study conducted among atrial fibrillation patients using the UK Clinical Practice Research Datalink (March 2008-October 2014). Method New users of vitamin K antagonists, non vitamin K oral anticoagulants, low-dose aspirin, or combination therapy were followed from the date of first prescription to the date of death, as recorded in the UK datalink. Cox proportional hazard models estimated the hazard ratio (HR) of all-cause mortality for users of NOACs, aspirin, or combination use, as compared to vitamin K antagonist. Analyses were adjusted for confounders. Main outcome measure All-cause mortality. Results We identified 31,497 patients. Non vitamin K antocoagulant use (adjusted HR [aHR] = 1.42; 95% Confidence Interval [CI] 1.18-1.71) and aspirin use (aHR = 1.64; 95% CI 1.57-1.77) were both significantly associated with a higher mortality risk than use of vitamin K antagonists. The higher mortality risk for the non vitamin K anticoagulant use was observed in men (aHR = 1.72; 95% CI 1.25-2.36), but not in women (aHR = 1.28; 95% CI 0.92-1.79. Compared to  vitamin K antagonists, mortality risk associated with the non vitamin K anticoagulants and aspirin use was significantly increased in patients with higher stroke risk (CHA₂DS₂-VASc > 2). Conclusion Non vitamin K oral anticoagulants are  associated with a higher risk on all-cause mortality, particularly in men and in patients with higher stroke risk.

Systematic review of the evidence on the cost-effectiveness of pharmacogenomics-guided treatment for cardiovascular diseases

PURPOSE

To examine the evidence on the cost-effectiveness of implementing pharmacogenomics (PGx) in cardiovascular disease (CVD) care.

METHODS

We conducted a systematic review using multiple databases from inception to 2018. The titles and abstracts of cost-effectiveness studies on PGx-guided treatment in CVD care were screened, and full texts were extracted.

RESULTS

We screened 909 studies and included 46 to synthesize. Acute coronary syndrome and atrial fibrillation were the predominantly studied conditions (59%). Most studies (78%) examined warfarin-CYP2C9/VKORC1 or clopidogrel-CYP2C19. A payer's perspective was commonly used (39%) for cost calculations, and most studies (46%) were US-based. The majority (67%) of the studies found PGx testing to be cost-effective in CVD care, but cost-effectiveness varied across drugs and conditions. Two studies examined PGx panel testing, of which one examined pre-emptive testing strategies.

CONCLUSION

We found mixed evidence on the cost-effectiveness of PGx in CVD care. Supportive evidence exists for clopidogrel-CYP2C19 and warfarin-CYP2C9/VKORC1, but evidence is limited in other drug-gene combinations. Gaps persist, including unclear explanation of perspective and cost inputs, underreporting of study design elements critical to economic evaluations, and limited examination of PGx panel and pre-emptive testing for their cost-effectiveness. This review identifies the need for further research on economic evaluations of PGx implementation.