Real-world comparison of major bleeding risk among non-valvular atrial fibrillation patients initiated on apixaban, dabigatran, rivaroxaban, or warfarin. A propensity score matched analysis

Real-world on-treatment and initial treatment absolute risk differences for dabigatran vs warfarin in older US adults

PURPOSE

Trials and past observational work compared dabigatran and warfarin in patients with atrial fibrillation, but few reported estimates of absolute harm and benefit under real-world adherence patterns, particularly in older adults that may have differing benefit-harm profiles. We aimed to estimate risk differences for ischemic stroke, death, and gastrointestinal bleeding after initiating dabigatran and warfarin in older adults (a) when patients adhere to treatment and (b) under real-world adherence patterns.

METHODS

In a 20% sample of nationwide Medicare claims from 2010 to 2015, we identified beneficiaries aged 66 years and older initiating warfarin and dabigatran. We followed individuals from initiation until death or October 2015 (initial treatment, IT) and separately censored individuals' follow-up after drug switches and gaps in supply (on-treatment, OT). We applied inverse probability of treatment and standardized morbidity ratio weights, as well as inverse probability of censoring weights, to estimate two-year risk differences (RDs) for dabigatran vs warfarin.

RESULTS

We identified 10,717 dabigatran and 74,891 warfarin initiators. Weighted OT RDs suggested decreased ischemic stroke risk for dabigatran vs warfarin; IT RDs indicated increased or no change in ischemic stroke risk. Regardless of follow-up approach and weighting strategy, risk of death appeared lower and risk of gastrointestinal bleeding appeared higher when comparing dabigatran vs warfarin.

CONCLUSIONS

Dabigatran use was associated with lower risks of mortality and ischemic stroke in routine care when older adults stayed on treatment. IT analyses suggested that these benefits may be diminished under real-world patterns of switching and discontinuation.

Treatment strategies for patients with atrial fibrillation and anticoagulant-associated intracranial hemorrhage: an overview of the pharmacotherapy

INTRODUCTION

Oral anticoagulants (OAC) reduce stroke/systemic embolism and mortality risks in atrial fibrillation (AF). However, there is an inherent bleeding risk with OAC, where intracranial hemorrhage (ICH) is the most feared, disabling, and lethal complication of this therapy. Therefore, the optimal management of OAC-associated ICH is not well defined despite multiple suggested strategies.

AREAS COVERED

In this review, the authors describe the severity and risk factors for OAC-associated ICH and the associated implications for using DOACs in AF patients. We also provide an overview of the management of OAC-associated ICH and treatment reversal strategies, including specific and nonspecific reversal agents as well as a comprehensive summary of the evidence about the resumption of DOAC and the optimal timing.

EXPERT OPINION

In the setting of an ICH, supportive care/measures are needed, and reversal of anticoagulation with specific agents (including administration of vitamin K, prothrombin complex concentrates, idarucizumab and andexanet alfa) should be considered. Most patients will likely benefit from restarting anticoagulation after an ICH and permanently withdrawn of OAC is associated with worse clinical outcomes. Although the timing of OAC resumption is still under debate, reintroduction after 4-8 weeks of the bleeding event may be possible, after a multidisciplinary approach to decision-making.

Bleeding Risk in Nonvalvular Atrial Fibrillation Patients Receiving Direct Oral Anticoagulants and Warfarin: A Systematic Review and Meta-Analysis of Observational Studies

Introduction  In randomized trials in atrial fibrillation (AF) patients on direct oral anticoagulants (DOACs) have a lower risk of bleeding compared with warfarin. However, data from randomized trials may not extrapolate to general population. We aimed to determine the risk of bleeding in patients on DOACs in observational studies. Materials and Methods  Observational studies from 1990 to January 2019 were included. A pooled effect hazard ratio (HR) was calculated with a random effects model using the generic inverse variance method. Subgroup analyses according to previous anticoagulants exposure, study type, funding source, and DOAC type (direct thrombin inhibitors vs. factor Xa inhibitors) were conducted. Results  A total of 35 studies comprising 2,356,201 patients were included. The average pooled HR for observational data was 0.78 (95% confidence interval [CI] 0.71, 0.85). There were no statistically significant differences in pooled HR by previous exposure to anticoagulants, DOAC type (direct thrombin vs. factor Xa inhibitors), study type, and funding source. Among patients receiving factor Xa inhibitors, patients on apixaban had a lower risk of bleeding compared with warfarin (HR 0.60, 95% CI 0.50, 0.71, p  < 0.001) in contrast to those on rivaroxaban (HR 0.98, 95% CI 0.91, 1.06, p  = 0.60). Conclusion  In observational studies, AF patients on DOACs experience less bleeding events compared with warfarin; however, apixaban and dabigatran, but not rivaroxaban, have a lower risk of bleeding than warfarin.

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.

Real-world cost-effectiveness of rivaroxaban and apixaban vs VKA in stroke prevention in non-valvular atrial fibrillation in the UK

BACKGROUND

Morbidity and mortality associated with non-valvular atrial fibrillation (NVAF) imposes a substantial economic burden on the UK healthcare system.

OBJECTIVES

An existing Markov model was adapted to assess the real-world cost-effectiveness of rivaroxaban and apixaban, each compared with a vitamin K antagonist (VKA), for stroke prevention in patients with NVAF from the National Health Service (NHS) and personal and social services (PSS) perspective.

METHODS

The model considered a cycle length of 3 months over a lifetime horizon. All inputs were drawn from real-world evidence (RWE): baseline patient characteristics, clinical event and persistence rates, treatment effect (meta-analysis of RWE studies), utility values and resource use. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

The incremental cost per quality-adjusted life year was £14,437 for rivaroxaban, and £20,101 for apixaban, compared with VKA. The probabilities to be cost-effective compared with VKA were 90% and 81%, respectively for rivaroxaban and apixaban, considering a £20,000 threshold. In both comparisons, the results were most sensitive to clinical event rates.

CONCLUSIONS

These results suggest that rivaroxaban and apixaban are cost-effective vs VKA, based on RWE, considering a £20,000 threshold, from the NHS and PSS perspective in the UK for stroke prevention in patients with NVAF. This economic evaluation may provide valuable information for decision-makers, in a context where RWE is more accessible and its value more acknowledged.

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.

Incidence Rates of Bleeding and Emergency Surgery Due to Trauma or Fracture Among Japanese Patients with Non-valvular Atrial Fibrillation Receiving Oral Anticoagulation Therapy

Introduction

In patients with nonvalvular atrial fibrillation (NVAF) receiving oral anticoagulants (OACs), reversal of coagulopathy can be achieved with specific reversal drugs such as idarucizumab, which is indicated for use in patients treated with dabigatran for cases of life-threatening or uncontrolled bleeding or during emergency procedures that may cause serious bleeding. This study examined the incidence rate (IR) of emergency surgeries and major bleeding episodes associated with fractures and trauma in Japanese patients with NVAF receiving OACs.

Methods

This retrospective, non-interventional analysis of health insurance claims was conducted using data from 62,888 OAC-naive adult patients with NVAF who initiated dabigatran, warfarin, apixaban, rivaroxaban, or edoxaban between March 2011 and June 2016. The primary endpoint was overall IR of emergency surgery or major bleeding due to fracture or trauma.

Results

Overall IR of emergency surgery or major bleeding due to fracture or trauma considering outcomes until OAC discontinuation was 0.489 per 100 patient-years (PY) (95% confidence interval [CI] 0.406–0.572). Considering first OAC exposure only, the IR was 0.483 per 100 PY (95% CI 0.394–0.573). Emergency surgery/major bleeding events due to fracture or trauma was highest in those aged ≥ 75 years (0.611 per 100 PY [95% CI 0.481–0.741]).

Conclusions

Fewer than one in 200 patients per year with NVAF receiving OACs experience emergency surgeries and major bleeding episodes associated with fractures and trauma; however, the IR of these events is markedly higher in patients of advanced age.

Trial registration

ClinicalTrials.gov 207, NCT03254147.

Patients with an abnormal heart rhythm (nonvalvular atrial fibrillation [NVAF]) have a higher risk of blood clots and stroke (which is when the blood supply to part of the brain is blocked). To reduce these risks, patients can take anticoagulants that slow or prevent the formation of blood clots. However, if the patient needs major emergency surgery or has a severe injury, the anticoagulants can increase their risk of bleeding, which can sometimes be life-threatening. There are drugs (e.g., idarucizumab) that can be used to reverse the effects of anticoagulants in this type of emergency. What we don’t know is how many NVAF patients in Japan who are on anticoagulants have emergency surgeries or major bleeding after an injury, and therefore may require a reversal drug. The authors looked at Japanese health insurance claim data from 62,888 adult patients with NVAF who started taking an anticoagulant. They found that, annually, approximately 0.5% of the patients had emergency surgery or a major bleed associated with a fracture or injury. In very elderly patients (aged at least 75 years), the annual percentage was approximately 0.6%, which was almost double the annual percentage in patients aged less than 65 years. The authors concluded that, even though the number of people requiring a reversal agent are quite small, it is important to have an effective reversal agent for patients on anticoagulants, particularly older patients.

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.

Safety and effectiveness of non-vitamin K oral anticoagulants versus warfarin in real-world patients with non-valvular atrial fibrillation: a retrospective analysis of contemporary Japanese administrative claims data

Objective

To assess the safety (ie, risk of bleeding) and effectiveness (ie, risk of stroke/systemic embolism (SE)) separately for four non-vitamin K oral anticoagulants (NOACs; apixaban, dabigatran, edoxaban and rivaroxaban) versus warfarin in Japanese patients with non-valvular atrial fibrillation (NVAF), including those at high risk of bleeding and treated with reduced doses of NOACs.

Methods

We conducted a retrospective analysis of electronic health records and claims data from 372 acute care hospitals in Japan for patients with NVAF newly initiated on NOACs or warfarin. Baseline characteristics were balanced using inverse probability of treatment weighting with stabilised weights (s-IPTW). Bleeding risk and stroke/SE risk were expressed as HRs with 95% CIs. Two sensitivity analyses were conducted.

Results

A total of 73 989 patients were eligible for analysis. Notably, 52.8%-81.9% of patients received reduced doses of NOACs. After applying s-IPTW, patient characteristics were well balanced across warfarin/NOAC cohorts. The mean within-cohort age, CHADS₂ score and CHA₂DS₂-VASc score were 76 years, 2.2-2.3 and 3.8, respectively. In all age categories, the majority of the HRs for major bleeding, any bleeding and stroke/SE were equal to or below 1 for all NOACs versus warfarin. Apixaban was the only NOAC associated with a significantly lower risk of any bleeding. There was a trend towards increased risk reduction with NOACs versus warfarin in patients with body weight ≥60 kg. In patients with renal disease, the HRs for apixaban versus warfarin were below 1 for major bleeding, any bleeding and stroke/SE, with statistical significance observed for the risk reduction in stroke/SE versus warfarin. In the sensitivity analysis, there were no large differences in HRs between the two observational periods.

Conclusions

In patients with NVAF primarily treated with reduced-dose NOACs, the risks of stroke/SE and major bleeding were significantly lower with NOACs versus warfarin.

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.

Impact of liver disease on oral anticoagulant prescription and major adverse events in patients with atrial fibrillation: analysis from a population-based cohort study

AIMS 

Data on the impact of liver disease (LD) in patients with atrial fibrillation (AF) and the role of oral anticoagulant (OAC) drugs for stroke prevention are limited.

METHODS AND RESULTS 

A retrospective observational population-based cohort study on the administrative health databases of Lombardy region Italy. All AF patients ≥40 years admitted to hospital from 2000 to 2018 were considered. Atrial fibrillation and LD diagnosis were established using ICD9-CM codes. Use of OAC was determined with Anatomical Therapeutic Chemical codes. Primary study outcomes were stroke, major bleeding, and all-cause death. Among 393 507 AF patients, 16 168 (4.1%) had concomitant LD. Liver disease AF patients were significantly less treated with OAC. Concomitant LD was associated with an increased risk in all the study outcomes [hazard ratio (HR): 1.18, 95% confidence interval (CI): 1.11-1.25 for stroke; HR: 1.57, 95% CI: 1.47-1.66 for major bleeding; HR: 1.41, 95% CI: 1.39-1.44 for all-cause death]. Use of OAC in patients with AF and LD resulted in a reduction in stroke (HR: 0.80, 95% CI: 0.70-0.92), major bleeding (HR: 0.86, 95% CI: 0.74-0.99), and all-cause death (HR: 0.77, 95% CI: 0.73-0.80), with similar results according to subgroups. A net clinical benefit (NCB) analysis suggested a positive benefit/risk ratio in using OAC in AF patients with LD (NCB: 0.408, 95% CI: 0.375-0.472).

CONCLUSION

In AF patients, concomitant LD carries a significantly higher risk for all clinical outcomes. Use of OAC in AF patients with LD was associated with a significant favourable benefit/risk ratio, even in high-risk patient subgroups.

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.

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.

Equivalent inpatient mortality among direct-acting oral anticoagulant and warfarin users presenting with major hemorrhage

BACKGROUND

Extrapolation of clinical trial results comparing warfarin and direct-acting oral anticoagulant (DOAC) users experiencing major hemorrhage to clinical care is challenging due to differences seen among non-randomized oral anticoagulant users, bleed location, and etiology. We hypothesized that inpatient all-cause-mortality among patients presenting with major hemorrhage differed based on the home-administered anticoagulant medication class, DOAC versus warfarin.

METHODS

More than 1.5 million hospitalizations were screened and 3731 patients with major hemorrhage were identified in the REDS-III Recipient Database. Propensity score matching and stratification were used to account for potentially confounding factors.

RESULTS

Inpatient all-cause-mortality was lower for DOAC (HR = 0.60, 95%CI 0.45-0.80, p = 0.0005) before accounting for confounding and competing events. Inpatient all-cause-mortality for 1266 propensity-score-matched patients compared using proportional hazards regression did not differ (HR = 0.84, 95%CI 0.58-1.22, p = 0.36). Inpatient all-cause-mortality in stratified analyses (warfarin as reference) produced: HR = 0.69 (95%CI 0.31-1.55) for traumatic head injuries; HR = 1.10 (95%CI 0.62-1.95) for non-traumatic head injuries; HR = 0.62 (95%CI 0.20-1.94) for traumatic, non-head injuries; and HR = 0.69 (95%CI 0.29-1.63) for non-traumatic, non-head injuries. Mean time to discharge was shorter for DOAC (HR = 1.17, 95%CI 1.05-1.30, p = 0.0034) in the propensity score matched analysis. Plasma transfusion occurred in 42% of warfarin hospitalizations and 11% of DOAC hospitalizations. Vitamin K was administered in 63% of warfarin hospitalizations.

CONCLUSIONS

After accounting for differences in patient characteristics, location of bleed, and traumatic injury, inpatient survival was no different in patients presenting with major hemorrhage while on DOAC or warfarin.

Evaluation of oral anticoagulants in atrial fibrillation patients over 80 years of age with nonsevere frailty

BACKGROUND

The safety and efficacy of an oral anticoagulant (OAC) treatment and the difference between direct OACs (DOACs) and warfarin in nonsevere frail elderly patients with AF are unclear.

METHODS

This was a retrospective and observational study of 354 patients over 80 years of age with nonsevere frailty who were diagnosed with AF and treated with OACs. Nonsevere frailty was defined as a clinical frailty scale score of <7. Bleeding and thromboembolic events during the OAC treatment were followed up.

RESULTS

Of 354 patients enrolled, 273 (77.1%) received DOACs and 81 (22.9%) received warfarin. Of 273 patients receiving DOACs, there were 210 (76.9%) prescribed with appropriate doses of DOACs. Of 81 warfarin-treated patients, 53 (65.4%) were prescribed an appropriate dose of warfarin. During a follow-up of 33.1 (14.0-51.0) months, 15 patients (1.5/100 person-years) had bleeding events and 10 (1.0/100 person-years) had thromboembolic events while on an OAC treatment. The incidence ratio of bleeding events in patients receiving DOACs was lower than that in those receiving warfarin (1.0/100 person-years vs 2.9/100 person-years, hazard ratio [HR]: 0.26, 95% confidence interval [CI]: 0.07-0.91, P = .036). There was no significant difference in the incidence of thromboembolic events between the DOAC and warfarin treatment groups (0.88/100 person-years vs 1.4/100 person-years, HR: 0.63, 95% CI: 0.16-2.57, P = .52).

CONCLUSIONS

OACs are substantially safe and effective for preventing thromboembolic events in nonsevere frail patients over 80 years of age. Particularly, DOACs can be used more safely than warfarin.

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).

Evaluation of the safety and effectiveness of direct oral anticoagulants and low molecular weight heparin in gastrointestinal cancer-associated venous thromboembolism

BACKGROUND

Gastrointestinal cancer (GICA) is associated with a higher incidence of venous thromboembolism (VTE) compared to other solid tumors, moreover, recurrent VTE and major bleeding (MB) complications during anticoagulation treatment have an associated increase rate. GICA-VTE remains a challenging clinical scenario with MB concerns for utilization of direct oral anticoagulants (DOAC), especially with active cancer therapies.

AIM

To evaluate patient risk factors, effectiveness (VTE) and safety (MB) of DOACs and low molecular weight heparin (LMWH) in patients with active GICA-VTE.

METHODS

A retrospective chart review of patients receiving DOACs and LMWH with GICA and symptomatic or incidental VTE treated at comprehensive cancer center from November 2013 to February 2017 was performed. Inclusion criteria included active GI cancer diagnosed at any stage or treatment +/- 6 mo of VTE diagnosis, whom were prescribed 6 mo or more of DOACs or LMWH. The Chi-squared test was used for overall and the Fisher exact test for pairwise comparisons of the proportions of patients experiencing recurrent VTE and MB events. Odds ratios were used to compare the relative odds of the occurrence of the outcome given exposure to the risk factor.

RESULTS

A total of 144 patients were prescribed anticoagulation, in which 106 fulfilled inclusion criteria apixaban (27.3%), rivaroxaban (34.9%) and enoxaparin (37.7%), and 38 were excluded. Patients median age was 66.5 years at GICA diagnosis and 67 years at CAVTE event, with 62% males, 80% Caucasian, 70% stage IV, pancreatic cancer (40.5%), 30% Khorana Score (≥ 3 points), and 43.5% on active chemotherapy. Sixty-four percent of patients completed anticoagulation therapy (range 1 to 43 mo). Recurrent VTE at 6 mo was noted in 7.5% (n = 3), 6.8% (n = 2) and 2.7% (n = 1) of patients on enoxaparin, apixaban and rivaroxaban, respectively (all P = NS). MB at 6 mo were 5% (n = 2) for enoxaparin, 6.8% (n = 2) for apixaban and 21.6% (n = 8) for rivaroxaban (overall P = 0.048; vs LMWH P = 0.0423; all other P = NS). Significant predictors of a primary or secondary outcome for all anticoagulation therapies included: Active systemic treatment (OR = 5.1, 95%CI: 1.3-19.3), high Khorana Score [≥ 3 points] (OR = 5.5, 95%CI: 1.7-17.1), active smoker (OR = 6.7, 95%CI: 2.1-21.0), pancreatic cancer (OR = 6.8, 95%CI: 1.9-23.2), and stage IV disease (OR = 9.9, 95%CI: 1.2-79.1).

CONCLUSION

Rivaroxaban compared to apixaban and enoxaparin had a significantly higher risk of MB on GICA-VTE patients with equivocal efficacy.

Direct-Acting Oral Anticoagulants and Their Reversal Agents-An Update

Background: Over the last ten years, a new class of drugs, known as the direct-acting oral anticoagulants (DOACs), have emerged at the forefront of anticoagulation therapy. Like the older generation anticoagulants, DOACs require specific reversal agents in cases of life-threatening bleeding or the need for high-risk surgery. Methods: Published literature was searched, and information extracted to provide an update on DOACS and their reversal agents. Results: The DOACs include the direct thrombin inhibitor—dabigatran, and the factor Xa inhibitors—rivaroxaban, apixaban, edoxaban, and betrixaban. These DOACs all have a rapid onset of action and each has a predictable therapeutic response requiring no monitoring, unlike the older anticoagulants, such as warfarin. Two reversal agents have been approved within the last five years: idarucizumab for the reversal of dabigatran, and andexanet alfa for the reversal of rivaroxaban and apixaban. Additionally, ciraparantag, a potential “universal” reversal agent, is currently under clinical development. Conclusions: A new generation of anticoagulants, the DOACs, and their reversal agents, are gaining prominence in clinical practice, having demonstrated superior efficacy and safety profiles. They are poised to replace traditional anticoagulants including warfarin.

A drug safety evaluation of apixaban for the treatment of atrial fibrillation, acute coronary syndrome, and percutaneous coronary intervention

Introduction: The non-vitamin K antagonist oral anticoagulants (NOACs) are changing the landscape for stroke prevention in atrial fibrillation (AF) and prevention or treatment of venous thromboembolism (VTE). In patients with AF and concomitant acute coronary syndrome (ACS), the treatment regimen of combined NOACs and P2Y₁₂ inhibitors is gaining popularity.Areas covered: We conducted a review of safety evaluation and effectiveness of apixaban for AF and ACS treatment, both alone and in combination with different antiplatelet treatment regimens. The aim was to provide an overview of apixaban including mechanism of action, indications, adverse events and tolerability.Expert opinion: Apixaban is recommended as a safe, well tolerated and effective oral anticoagulant for reducing the risk of ischemic events among AF patients. It is of value in prevention and treatment of VTE and pulmonary embolism. Comparing to VKA, apixaban was superior in preventing stroke or systemic embolism with lower major bleeding events among AF patients. When combined with dual antiplatelet therapy apixaban may cause dose-related increase in bleeding which reduces the benefit of this treatment regimen among ACS patients but without AF. In those with ACS and concomitant AF, the combination of apixaban with P2Y₁₂ inhibitor appears to be safe and effective.

Patient characteristics and stroke and bleeding events in nonvalvular atrial fibrillation patients treated with apixaban and vitamin K antagonists: a Spanish real-world study

Aim: To compare the risk of stroke, systemic thromboembolism and bleeding, in patients initiating apixaban or acenocoumarol for the treatment of nonvalvular atrial fibrillation. Methods: An observational, retrospective study was performed using medical records of patients who initiated apixaban or acenocoumarol between 2015 and 2017. Propensity score matching was used to match patients; stroke, systemic thromboembolism, major and minor bleeding events were compared between the matched patients. Results: Patients who were prescribed apixaban had a lower rate of systemic embolism/stroke (hazard ratio [HR] = 0.54; 95% CI: 0.38–0.78; p = 0.001), minor bleeding (HR = 0.64; 95% CI: 0.52–0.79; p < 0.001) and major bleeding (HR = 0.51; 95% CI: 0.37–0.72; p < 0.001). Conclusion: Patients prescribed apixaban for the treatment of nonvalvular atrial fibrillation had lower rates of thromboembolic events and minor/major bleeding than patients on acenocoumarol.

Differences In Gastrointestinal Safety Profiles Among Novel Oral Anticoagulants: Evidence From A Network Meta-Analysis

Background

There is no consensus at present regarding the differences in the risk of GI bleeding across various NOAC regimens. Therefore, we performed a network meta-analysis to compare the risk of gastrointestinal bleeding after different NOAC regimens.

Methods

PubMed, Cochrane, Web of Science, Clinicaltrial.gov and Clinicaltrialresults.org were searched for randomized controlled trials (RCTs) assessing gastrointestinal bleeding of all NOAC regimens from inception to January 2018. The primary endpoint was major gastrointestinal (MGI) bleeding. The meta-regression was performed to access the association between the MGI bleeding events and mortality. The network meta-analysis was carried out with the Bayesian random-effect model.

Results

A total of 25 RCTs, including 139,392 patients, were identified. Meta-regression analysis showed that MGI bleeding was correlated with fatal bleeding events (odds ratios [OR], 1.76; 95% confidence interval [CI], 1.13-2.77], P=0.015). The network meta-analysis results showed that compared to the conventional regimens, rivaroxaban was associated with increased risk of MGI bleeding (OR, 1.37; 95% credible interval [CrI], 1.00-1.85), but not the apixaban (OR, 0.77; 95% CrI, 0.53-1.07]), edoxaban (OR, 0.86; 95%CrI, 0.52-1.18) and dabigatran etexilate (OR, 1.22; 95% CrI, 0.82-1.69). Compared to rivaroxaban, apixaban (OR, 0.56; 95% CrI, 0.35-0.88) and edoxaban (OR, 0.62; 95% CrI, 0.35-0.96) showed a significantly lower risk of MGI bleeding. Apixaban had the highest probability of being the safest option with regard to the risk of MGI bleeding (89.1%), followed by edoxaban (77.4%), conventional therapy (51.4%), dabigatran etexilate (23.8%) and rivaroxaban (8.3%).

Conclusion

The risk of GI bleeding significantly varies among different NOAC regimens, and evidence shows that apixaban and edoxaban had the most favorable MGI bleeding safety profile, while rivaroxaban and dabigatran etexilate were the least safe.

Warfarin vs. apixaban in nonvalvular atrial fibrillation, and analysis by concomitant antiarrhythmic medication use: A national retrospective study

BACKGROUND

No real-world data exist on outcomes in patients on anticoagulants and concomitant antiarrhythmic medications. This study aims to compare the safety and effectiveness of apixaban and warfarin, first in patients with nonvalvular atrial fibrillation (NVAF) and then in patients on concurrent antiarrhythmic medications.

METHODS

A retrospective cohort study was conducted using a large US electronic medical record database (2012-2016). Patients with NVAF on warfarin or apixaban were included. The primary endpoint was a composite of stroke (ischemic or hemorrhagic) or systemic embolism. The primary safety endpoint was major bleeding (ISTH definition). Patients were matched using propensity scoring. Univariate survival analyses were conducted by using the log-rank test and Kaplan-Meier survival curves. A subgroup analysis was conducted to assess outcomes on patients on concurrent antiarrhythmic medications.

RESULTS

A total of 332 100 patients with NVAF were identified, and 20 378 were included in the propensity-matching analysis. No baseline differences were seen in age, comorbidities, or CHA 2 DS 2-VASc score. The primary endpoint occurred in 122 (1.2%) patients on apixaban compared to 166 (1.63%) on warfarin (hazard ratio, 0.84; 95% confidence interval [CI], 0.79-0.88). Major bleeding occurred at a lower rate in the apixaban group (n = 600, 5.89%) compared to warfarin (n = 887, 8.71%) (odds ratio, 0.65; 95% CI, 0.58-0.73). In patients on concurrent antiarrhythmic medications (n = 2498), there was no difference in thrombotic (1.04% vs. 1.37%; P = 0.42) or bleeding events (5.29% vs. 6.89%; P = 0.08).

CONCLUSION

Apixaban was associated with reduced stroke/systemic embolism and bleeding when compared with warfarin. No difference was seen in thrombotic or bleeding events in patients on concurrent antiarrhythmic medications.

Pylephlebitis treated with apixaban

Pylephlebitis is a rare condition that is characterized by an infected thrombus of the portal vein system and was traditionally associated with a high mortality rate prior to the introduction of antibiotics. This report details a 77-year-old Chinese male found to have a splenic vein thrombosis, Parvimonas micra bacteremia, and a polymicrobial splenic abscess. The patient was treated with abscess drainage and a 6 week course of intravenous antibiotics, and a direct oral anticoagulant, apixaban 2.5 mg twice daily. To our knowledge, this is the second documented case of pylephlebitis treated with apixaban. Here, we summarize our experience treating this case of pylephlebitis and briefly report on the existing body of literature.

Comparison of bleeding risks among non-vitamin K antagonist oral anticoagulants using the Korea adverse event reporting system database

Background:

In order to ensure safer use of non-vitamin K antagonist oral anticoagulants (NOACs), continuously detecting unexpected adverse drug reactions (ADRs) after market approval is necessary.

Methods:

We performed disproportionality analysis to evaluate association between ADRs and NOACs including apixaban, dabigatran, and rivaroxaban using data from the Korea Institute of Drug Safety and Risk Management–Korea Adverse Event Reporting System database (KIDS-KD) between 2012 and 2016. There was no significant signal other than bleeding when considering quantity, signal strength, seriousness, and causality. In order to evaluate the NOAC reports about bleeding, we selected 62 WHO-ART diagnostic codes associated with bleeding. Among the 26 codes that referred to major bleeding, 18 codes referred to gastrointestinal bleeding and 8 were referred to intracranial bleeding. We evaluated the significance of the signals using reporting odds ratios (RORs) adjusted for age and sex.

Results:

Treatments with apixaban, dabigatran, and rivaroxaban were associated with 1989, 1668, and 2960 adverse events, respectively. Any type of bleeding with apixaban, dabigatran, rivaroxaban, and warfarin was reported in 174 (8.8%), 209 (12.5%), 523 (17.8%), and 620 (9.5%) events, respectively. For any bleeding, adjusted RORs of apixaban, dabigatran, and rivaroxaban were 0.99 [95% confidence interval (CI): 0.83–1.17], 1.47 (95% CI: 1.25–1.75), and 2.48 (95% CI: 2.16–2.84), respectively. With respect to major bleeding, the adjusted RORs of apixaban, dabigatran, and rivaroxaban were 1.08 (95% CI: 0.82–1.41), 1.46 (95% CI: 1.10–1.90), and 1.82 (95% CI: 1.43–2.32), respectively.

Conclusion:

Rivaroxaban might have stronger association with bleeding than apixaban and dabigatran.

Switching to Another Oral Anticoagulant and Drug Discontinuation Among Elderly Patients With Nonvalvular Atrial Fibrillation Treated With Different Direct Oral Anticoagulants

We compared the risks of switching to another oral anticoagulant (OAC) and discontinuation of direct oral anticoagulants (DOACs) among elderly patients with nonvalvular atrial fibrillation (NVAF) who were prescribed rivaroxaban or dabigatran versus apixaban. Patients (≥65 years of age) with NVAF prescribed DOACs (January 1, 2013 to September 30, 2017) were identified from the Humana research database and grouped into DOAC cohorts. Cox regression analyses were used to evaluate whether the risk for switching to another OAC or discontinuing index DOACs differed among cohorts. Of the study population (N = 38 250), 55.9% were prescribed apixaban (mean age: 78.6 years; 49.8% female), 37.3% rivaroxaban (mean age: 77.4 years; 46.7% female), and 6.8% dabigatran (mean age: 77.0 years; 44.0% female). Compared to patients prescribed apixaban, patients prescribed rivaroxaban (hazard ratio [HR]: 2.08; 95% confidence interval [CI], 1.92-2.25; P < .001) or dabigatran (HR: 3.74; 95% CI, 3.35-4.18, P < .001) had a significantly higher risk of switching to another OAC during the follow-up; compared to patients prescribed apixaban, the risks of discontinuation were also higher for patients treated with rivaroxaban (HR: 1.10; 95% CI, 1.07-1.13, P < .001) or dabigatran (HR: 1.29; 95% CI, 1.23-1.35, P < .001).

Drug interactions with oral anticoagulants in German nursing home residents: comparison between vitamin K antagonists and non-vitamin K antagonist oral anticoagulants based on two nested case-control studies

BACKGROUND

Vitamin K antagonists (VKAs) are susceptible to drug-drug interactions. Non-VKA oral anticoagulants (NOACs) have a decreased sensitivity to pharmacokinetic interactions and might be therefore considered superior in patients treated with multiple drugs. The objective of this study was to compare the risk of serious bleeding associated with interacting drugs in German nursing home residents treated with VKA or NOAC.

METHODS

Using claims data of new nursing home residents aged ≥ 65 years (2010-2014) we conducted separate nested case-control analyses within two cohorts of patients treated with VKA or NOAC, respectively. Cases were defined as patients hospitalized for serious bleeding. For each case, up to 20 controls were selected by risk-set sampling. Conditional logistic regression was used to obtain confounder-adjusted odds ratios (aORs) and 95% confidence intervals (CI) for the risk of bleeding associated with VKA or NOAC use and interacting drugs compared with the use of the respective oral anticoagulant alone.

RESULTS

Among 127,227 new nursing home residents, 16,804 patients received oral anticoagulation. Based on 372 cases and 7281 matched controls, the highest risk of bleeding in VKA users was observed for the concomitant use of antibiotics (aOR 3.00; CI 2.11-4.27) vs. VKA use alone, followed by non-steroidal anti-inflammatory drugs (1.66; 1.13-2.43). Among 243 NOAC cases and 4776 matched controls, elevated risks for bleeding were observed for the use of heparins (2.05; 1.25-3.36) and platelet inhibitors (1.92; 1.36-2.72).

CONCLUSIONS

Concomitant medication needs to be prescribed cautiously and monitored closely in nursing home residents treated with oral anticoagulants.

Effectiveness and Safety of Standard-Dose Nonvitamin K Antagonist Oral Anticoagulants and Warfarin Among Patients With Atrial Fibrillation With a Single Stroke Risk Factor: A Nationwide Cohort Study

Importance

The randomized clinical trials comparing nonvitamin K antagonist oral anticoagulants (NOACs) vs warfarin largely focused on recruiting high-risk patients with atrial fibrillation with more than 2 stroke risk factors, with only the trials testing dabigatran or apixaban including few patients with 1 stroke risk factor. Despite this, regulatory approvals of all NOACs have been based on stroke prevention for patients with atrial fibrillation with 1 or more stroke risk factors.

Objective

To compare the effectiveness and safety study of standard-dose NOACs (dabigatran at 150 mg twice daily, rivaroxaban at 20 mg once daily, and apixaban at 5 mg twice daily) and warfarin in patients with atrial fibrillation with 1 low-risk, nonsex-related stroke risk factor.

Design, Setting, and Participants

This nationwide observational cohort study used data from Danish registries to determine the inverse probability of treatment-weighted comparative effectiveness and safety of standard-dose NOACs (dabigatran at 150 mg twice daily, rivaroxaban at 20 mg once daily, and apixaban at 5 mg twice daily) compared with treatment with warfarin among 14 020 patients with atrial fibrillation with 1 low-risk, nonsex- related stroke risk factor.

Main Outcomes and Measures

Rates of ischemic stroke/systemic embolism, death, and bleeding.

Results

Of 14 020 participants, 5151 (36.7%) were women, and the median age for participants was 66.5 years. For the principal effectiveness end point of ischemic stroke/systemic embolism, no significant differences of the NOACs compared with treatment with warfarin across strata were evident. For the end point of "any bleeding," this was significantly lower for treatment with apixaban (hazard ratio [HR], 0.35; 95% CI, 0.17-0.72) and dabigatran (HR, 0.48; 95% CI, 0.30-0.77) compared with warfarin in the main analysis, and was not significantly different for treatment with rivaroxaban vs warfarin (HR, 0.84; 95% CI, 0.49-1.44). There was broad consistency across most subgroups in the sensitivity analyses and whether 1- or 2.5-year follow-up periods were analyzed. However, falsification end points generally did not falsify, indicating the possible presence of residual confounding across these comparisons, presumably related to selective prescribing and unobserved covariates.

Conclusions and Relevance

In this Danish cohort study of patients with atrial fibrillation and a single stroke risk factor, there was no difference between NOACs compared with treatment with warfarin in terms of the risk of having an ischemic stroke/systemic embolism. For "any bleeding," this was lower for treatment with apixaban and dabigatran compared with warfarin. These data do not allow for a definitive statement of the comparative effectiveness or safety of NOACs because of the possible residual confounding that was unmasked with falsification outcomes.

Profiling Clinical Characteristics and Treatment Patterns Among Non-Valvular Atrial Fibrillation Patients: A Real-World Analysis in Dubai, United Arab Emirates

Background:

There is a dearth of real-world evidence regarding patient characteristics, Oral Anti-Coagulant (OAC) treatment, and International Normalized Ratio (INR) patterns in Dubai, United Arab Emirates (UAE).

Methods:

This was a retrospective observational study among newly diagnosed adult Non-valvular Atrial Fibrillation (NVAF) patients in the Dubai Real World Claims Database. Selected patients had at least one activity claim during the 12 months pre-index date (baseline period), and a pharmacy claim for apixaban, dabigatran, rivaroxaban, or warfarin from 01 JAN 2015-31 JUL 2017. Patients with valvular heart disease, cardiac surgery, venous thromboembolism, transient atrial fibrillation, pregnancy, or OAC claims during baseline were excluded. Comorbidities and treatment patterns related to OAC use, index dosing, baseline medications, and INR patterns were described.

Results:

Among 5,072 NVAF patients, 468 met the study criteria. A minority of them (14.3%) were prescribed warfarin, and the most frequently prescribed non-vitamin K antagonist OACs (NOACs) were rivaroxaban (33.3%) and apixaban (31.4%), followed by dabigatran (20.9%). Patients’ mean age was 59 years and mean CHA2DS2-VASc score was 2.3, with most frequent comorbidities of diabetes mellitus, hypertension, coronary artery disease, and peripheral vascular disease. Additionally, 51% and 33% were on statins and aspirin, respectively, while 39% were on other anticoagulant agents. A large proportion of dabigatran patients were on a lower dose (57%). INR patterns revealed 13% of rivaroxaban, 12% of apixaban, and 7% of dabigatran patients had INR claims.

Conclusion:

This study provides relevant insights into the use of OACs in real-world clinical practice settings in Dubai, UAE.

Comparison of Once-Daily Administration of Edoxaban and Rivaroxaban in Asian Patients with Atrial Fibrillation

It is unclear whether the two once-daily dosing non-vitamin K antagonist oral anticoagulants (NOACs), edoxaban and rivaroxaban, have similar effectiveness and safety in Asian patients with non-valvular atrial fibrillation (AF). This study aimed to compare the effectiveness and safety of edoxaban and rivaroxaban in a Korean population with non-valvular AF. Using the Korean National Health Insurance Service database from January 2014 to December 2016, we compared the risk of ischemic stroke, intracranial hemorrhage (ICH), hospitalization for gastrointestinal (GI) bleeding, hospitalization for major bleeding, all-cause death, and composite outcome in a 3:1 propensity score matched cohort in patients with AF who were naïve to rivaroxaban (n = 12,369) and edoxaban (n = 4,123). Hazard ratios for the six clinical outcomes were analyzed using Cox regression analysis with rivaroxaban as the reference. Baseline characteristics were balanced between the two groups (median age, 71 years; median CHA₂DS₂-VASc score, 3; 56% of patients received a reduced dose). Edoxaban users showed comparable results in all six clinical outcomes (all p = nonsignificant) when compared to rivaroxaban users for total, standard, and reduced doses. We provide for the first time the comparison of effectiveness and safety between the two once-daily NOACs in a large-scale Asian AF population. In both standard and reduced dose regimens, edoxaban showed comparable effectiveness and safety compared to rivaroxaban.

Comparative safety and effectiveness of dabigatran vs. rivaroxaban and apixaban in patients with non-valvular atrial fibrillation: a retrospective study from a large healthcare system

AIMS

We used the US Department of Defense Military Health System database to compare the safety and effectiveness of direct oral anticoagulants (DOACs) in patients with non-valvular atrial fibrillation (NVAF) initiating dabigatran vs. rivaroxaban or apixaban.

METHODS AND RESULTS

Two cohorts of adults with NVAF, newly initiated on standard-dose DOAC, were identified based on clinical approval dates: July 2011-June 2016 for dabigatran (150 mg b.i.d.) or rivaroxaban (20 mg QD) and January 2013-June 2016 for dabigatran (150 mg b.i.d.) or apixaban (5 mg b.i.d.). Propensity score matching (1:1) identified two well-balanced cohorts (dabigatran vs. rivaroxaban n = 12 763 per treatment group; dabigatran vs. apixaban n = 4802 per treatment group). In both cohorts, baseline characteristics and follow-up duration were similar between treatment groups. Patients newly initiating dabigatran had significantly lower risk of major bleeding vs. rivaroxaban [2.08% vs. 2.53%; hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.70-0.97; P = 0.018], while stroke risk was similar (0.60% vs. 0.78%; HR 0.77, 95% CI 0.57-1.04; P = 0.084). The dabigatran vs. apixaban cohort analysis found no differences in risk of major bleeding (1.60% vs. 1.21%; HR 1.37, 95% CI 0.97-1.94; P = 0.070) or stroke (0.44% vs. 0.35%; HR 1.26, 95% CI 0.66-2.39; P = 0.489).

CONCLUSION

Among NVAF patients newly initiated on standard-dose DOAC therapy in this study, dabigatran was associated with significantly lower major bleeding risk vs. rivaroxaban, and no significant difference in stroke risk. For dabigatran vs. apixaban, the reduced sample size limited the ability to draw definitive conclusions.

Real-world adherence for direct oral anticoagulants in a newly diagnosed atrial fibrillation cohort: does the dosing interval matter?

Background

Differences in adherence may represent drug properties (e.g. dosing interval) or patient experiences while on treatment. Adherence to direct oral anticoagulants (DOACs) in nonvalvular atrial fibrillation (NVAF) is important to maintain effectiveness over the course of treatment.

Methods

This was a retrospective cohort study using 2009–2015 Truven Health MarketScan Databases. New initiators of dabigatran, rivaroxaban, and apixaban with NVAF were identified. Twelve months of continuous enrollment before treatment was required to assess demographics and medical history. Proportion of days cover (PDC) was used to measure adherence at 3, 6, 9 and 12-month. Gaps in therapy and treatment switches were also evaluated. Logistic regression was used to compare high adherence (PDC ≥0.80).

Results

A total of 14,864 dabigatran, 16,005 rivaroxaban, and 8078 apixaban users were identified. Apixaban users had the highest adherence overall, with mean PDC at 3, 6, 9, and 12-months of 0.83, 0.76, 0.72, and 0.69, while dabigatran had the lowest adherence of 0.78, 0.67, 0.61, and 0.57. Adherence to DOACs increased with increased stroke risk scores. Adherence was also higher when first days supplied was > 30 days compared to 30 days and when filled via mail order pharmacies. Switching was highest among dabigatran users. Apixaban users were the most likely to have high adherence versus dabigatran (OR = 1.73, 95% CI = 1.60–1.88) and versus rivaroxaban (OR = 1.24, 95% CI = 1.14–1.34) at 12-months.

Conclusions

Apixaban users had the highest overall adherence despite twice-daily dosing versus once-daily dosing for rivaroxaban. These findings can be useful for formulary decision-making and when assessing treatment options.

Safety of direct oral anticoagulants in real-world clinical practice: translating the trials to everyday clinical management

INTRODUCTION

Direct oral anticoagulants (DOACs) may be regarded as some of the most successful innovations in recent times. These drugs which were specifically developed to overcome the challenges posed by warfarin did just that and in the process, have changed the outlook towards stroke prevention with anticoagulation. The decade of experience with these drugs that has resulted in the availability of large scale data on their safety profile has aided this. Areas covered: This review examines existing real-world studies (RWS) and their interpretation to better appreciate how they either complement or contradict findings from the hallmark trials. Specific focus has been made on the safety of DOACs, on their risks of major bleeding, intra-cranial haemorrhage (ICH), gastro-intestinal (GI) bleeding and all-cause mortality compared to warfarin and each other. DOAC use in the elderly and other sub-groups are briefly discussed. Expert opinion: Results for safety outcomes according to 'real world evidence' (RWE) are in-keeping with randomised controlled trials (RCTs) and currently, all 4 DOACs have been deemed at least as effective as warfarin, while demonstrating superiority in some aspects. While real world studies act as a complementary source of knowledge, traditional RCTs remain the gold standard for determining cause-effect relationships.

Non-vitamin K oral anticoagulant use in the elderly: a prospective real-world study - data from the REGIstry of patients on Non-vitamin K oral Anticoagulants (REGINA)

Purpose

Numerous studies on thromboembolic prevention for non-valvular atrial fibrillation (NVAF) have shown either equal or better efficacy and safety of non-vitamin K oral anticoagulants (NOACs) compared to warfarin, even for patients aged ≥75 years. Data on elderly patients, in particular, octogenarians, are lacking. Paradoxically, this population is the one with the highest risk of bleeding and stroke with a worse prognosis. This study aims to describe safety and effectiveness of NOACs in an elderly comorbid population.

Patients and methods

REGIstry of patients on Non-vitamin K oral Anticoagulants (REGINA) is a prospective observational study enrolling consecutive NVAF patients started on NOACs and followed up to 1 year (at 1, 6, 12 months). The primary endpoint was the incidence rate of major bleeding (MB) and clinically relevant non-major bleeding (CRNMB). The secondary endpoints were the incidence of 1) stroke or systemic embolism, 2) hospitalization, 3) death, and 4) drug-related adverse events.

Results

We enrolled 227 patients aged 81.6±6.1 years (range 67–95 years; ≥80 years in 59.4%). The median CHA₂DS₂-VASc was 5 (IQR 4–5) and HAS-BLED was 4 (IQR 3–5). The estimated glomerular filtration rate was 59.27±24.12 mL/min. During follow-up, only 10 MB and 23 CRNMB occurred, with a total incidence of 4.4% (95% CI: 1.7%–7.17%) and 5.7% (95% CI: 2.68%–8.72%), respectively. There were 2 cerebral ischemic events, with a total incidence of 0.88% (95% CI: 0.84%–0.92%), 23 NOAC-related hospitalizations, no NOAC-related deaths, and 4 minor drug-related adverse effects.

Conclusion

In a population of aged and clinically complex patients, mainly octogenarians, NOACs were safe and effective.

Comparative safety and effectiveness of direct oral anticoagulants in patients with atrial fibrillation in clinical practice in Scotland

AIMS

The aim of this study was to compare the clinical effectiveness and safety of direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF) in routine clinical practice.

METHODS

This retrospective cohort study used linked administrative data. The study population (n = 14 577) included patients with a diagnosis of AF (confirmed in hospital) who initiated DOAC treatment in Scotland between August 2011 and December 2015. Multivariate Cox proportional hazard models were used to estimate hazard ratios of thromboembolic events, mortality and bleeding events.

RESULTS

No differences between the DOACs were observed with regard to the risk of stroke, systemic embolism or cardiovascular death. In contrast, the risk of myocardial infarction was higher among patients prescribed apixaban in comparison to those on rivaroxaban (HR 1.67, 95% CI 1.02-2.71), and all-cause mortality was higher among rivaroxaban patients in contrast to both apixaban (1.22 [1.01-1.47]) and dabigatran (1.55 [1.16-2.05]) patients; rivaroxaban patients also had a higher risk of pulmonary embolism than apixaban patients (5.27 [1.79-15.53]). The risk of other major bleeds was higher among rivaroxaban patients compared to apixaban (1.50 [1.10-2.03]) and dabigatran (1.58 [1.01-2.48]) patients; the risks of gastrointestinal bleeds and overall bleeding were higher among rivaroxaban patients than among apixaban patients (1.48 [1.01-2.16] and 1.52 [1.21-1.92], respectively).

CONCLUSIONS

All DOACs were similarly effective in preventing strokes and systemic embolisms, while patients being treated with rivaroxaban exhibited the highest bleeding risks. Observed differences in the risks of all-cause mortality, myocardial infarction and pulmonary embolism warrant further research.

Major bleeding with antithrombotic agents: a 2012-2015 study using the French nationwide Health Insurance database linked to emergency department records within five areas - rationale and design of SACHA study

Bleeding represents the most recognized and feared complications of antithrombotic drugs including oral anticoagulants. Previous studies showed inconsistent results on the safety profile. Among explanations, bleeding definition could vary and classification bias exists related to the lack of medical evaluation. To quantify the risk of major haemorrhagic event and event-free survival associated with antithrombotic drugs (vitamin K antagonist [VKA], non-VKA anticoagulant [NOAC], antiplatelet agent, parenteral anticoagulant) in 2012-2015, we linked the French nationwide Health Insurance database (SNIIRAM) with a local 'emergency database' (clinical and biological data collected in clinical records). In the VKA-NOAC comparison, a Cox regression analysis will be used to estimate the hazard ratio of major haemorrhagic event adjusted on gender, modified HAS-BLED score and comorbidities. A distinction on the type of major haemorrhagic event (intracranial, gastrointestinal and other haemorrhagic events) was made. We present here the study protocol and the database linkage results. Using six linkage keys, among 3 837 557 hospital visits identified in SNIIRAM, 5264 have been matched with a major haemorrhagic event identified in the 'emergency database', thus clinically confirmed. The 1090 unmatched haemorrhagic events could be explained by the fact that patients were not extracted in the SNIIRAM database (patients living in accommodation establishment with internal use of pharmacy, military people with specific insurance…). We showed the value of SNIIRAM enrichment with a clinical database, a necessary step to categorize haemorrhagic events by a clinically relevant definition and medical validation; it will allow to estimate more accuracy each type of haemorrhagic event.

Comparison of Drug Switching and Discontinuation Rates in Patients with Nonvalvular Atrial Fibrillation Treated with Direct Oral Anticoagulants in the United States

Introduction

Continuous usage of direct oral anticoagulants (DOACs) among nonvalvular atrial fibrillation (NVAF) patients is essential to maintain stroke prevention. We examined switching and discontinuation rates for the three most frequently initiated DOACs in NVAF patients in the USA.

Methods

Patients who initiated apixaban, rivaroxaban, or dabigatran (index event/date) were identified from the Pharmetrics Plus claims database (Jan 1, 2013–Sep 30, 2016, includes patients with commercial and Medicare coverage) and grouped into cohorts by index DOAC. Patients were required to have a diagnosis of NVAF and continuous health plan enrollment for 12 months prior to the index date (baseline period) and at least 3 months during the follow-up period. Drug switching rates to any other DOAC or warfarin and index DOAC discontinuation rate were evaluated separately with descriptive statistics, Kaplan–Meier analysis, and multivariable Cox regression analysis.

Results

Of the NVAF study population (n = 41,864), 37% initiated apixaban (n = 15,352; mean age 62 years), 51% initiated rivaroxaban (n = 21,250; mean age 61 years), and 13% initiated dabigatran (n = 5262; mean age 61 years). During the follow-up period, the unadjusted drug switching rates of patients treated with apixaban, rivaroxaban, and dabigatran were 3.6%, 6.3%, and 11.1%, respectively (p < 0.001 across the three cohorts); while the index DOAC discontinuation rates were 52.8%, 60.3%, and 62.9%, respectively (p < 0.001). After we controlled for differences in patient characteristics, patients treated with rivaroxaban (HR 1.8; 95% CI 1.6–2.0; p < 0.001) and dabigatran (HR 3.4; 95% CI 3.0–3.8, p < 0.001) had a significantly greater likelihood for drug switching than patients treated with apixaban. Also, both rivaroxaban (HR 1.1; 95% CI 1.1–1.2, p < 0.001) and dabigatran (HR 1.3; 95% CI 1.2–1.3, p < 0.001) treated patients were more likely to discontinue treatment.

Conclusion

In the real-world setting, patients with NVAF newly treated with apixaban were less likely to switch or discontinue treatment compared to patients treated with rivaroxaban or dabigatran.

Funding

Pfizer and Bristol-Myers Squibb.

Interventions for Preventing Thromboembolic Events in Patients With Atrial Fibrillation: A Systematic Review

BACKGROUND

The comparative safety and effectiveness of treatments to prevent thromboembolic complications in atrial fibrillation (AF) remain uncertain.

PURPOSE

To compare the effectiveness of medical and procedural therapies in preventing thromboembolic events and bleeding complications in adults with nonvalvular AF.

DATA SOURCES

English-language studies in several databases from 1 January 2000 to 14 February 2018.

STUDY SELECTION

Two reviewers independently screened citations to identify comparative studies of treatments to prevent stroke in adults with nonvalvular AF who reported thromboembolic or bleeding complications.

DATA EXTRACTION

Two reviewers independently abstracted data, assessed study quality and applicability, and rated strength of evidence.

DATA SYNTHESIS

Data from 220 articles were included. Dabigatran and apixaban were superior and rivaroxaban and edoxaban were similar to warfarin in preventing stroke or systemic embolism. Apixaban and edoxaban were superior and rivaroxaban and dabigatran were similar to warfarin in reducing the risk for major bleeding. Treatment effects with dabigatran were similar in patients with renal dysfunction (interaction P > 0.05), and patients younger than 75 years had lower bleeding rates with dabigatran (interaction P < 0.001). The benefit of treatment with apixaban was consistent in many subgroups, including those with renal impairment, diabetes, and prior stroke (interaction P > 0.05 for all). The greatest bleeding risk reduction was observed in patients with a glomerular filtration rate less than 50 mL/min/1.73 m2 (P = 0.003). Similar treatment effects were observed for rivaroxaban and edoxaban in patients with prior stroke, diabetes, or heart failure (interaction P > 0.05 for all).

LIMITATION

Heterogeneous study populations, interventions, and outcomes.

CONCLUSION

The available direct-acting oral anticoagulants (DOACs) are at least as effective and safe as warfarin for patients with nonvalvular AF. The DOACs had similar benefits across several patient subgroups and seemed safe and efficacious for a wide range of patients with nonvalvular AF.

PRIMARY FUNDING SOURCE

Patient-Centered Outcomes Research Institute. (PROSPERO: CRD42017069999).

Comparative Effectiveness and Safety of Rivaroxaban in Adults With Nonvalvular Atrial Fibrillation

BACKGROUND

All evidence regarding benefits and harms of rivaroxaban for stroke prevention has not been appraised yet.

STUDY QUESTION

What are the comparative effectiveness and safety of rivaroxaban in adults with nonvalvular atrial fibrillation?

DATA SOURCES

Randomized controlled trials (RCTs), meta-analyses, and observational studies were identified in several databases in October 2018.

STUDY DESIGN

Rapid review with evidence appraisal using the Grading of Recommendations Assessment, Development and Evaluation working group approach.

RESULTS

Two direct RCTs (23,021 patients) suggest that rivaroxaban is noninferior to warfarin in the prevention of stroke and systemic embolism (pooled relative risk [RR] 0.73, 95% confidence interval [CI], 0.43-1.24), reduces risk of hemorrhagic stroke (RR 0.59, 95% CI, 0.38-0.92), fatal bleeding (RR 0.49, 95% CI, 0.31-0.76), and cardiac arrest (RR 0.45, 95% CI, 0.25-0.82, 2 RCTs), but increases risk of major gastrointestinal bleeding (RR 1.46, 95% CI, 1.19-1.78). In observational studies, rivaroxaban is associated with lower risk of ischemic stroke (RR 0.87, 95% CI, 0.77-0.99, 222,750 patients), acute myocardial infarction (RR 0.61, 95% CI, 0.48-0.78, 73,739 patients), and intracranial hemorrhage (RR 0.64, 95% CI, 0.45-0.92, 197,506 patients) but higher risk of gastrointestinal bleeding (RR 1.30, 95% CI, 1.19-1.42, 188,968 patients) and higher risk of mortality when compared with warfarin in European studies (RR 1.19, 103,270 patients in the UK; RR 2.02, 22,358 patients in Denmark) but lower risk of mortality in Taiwan (RR 0.58, 40,000 patients). Network meta-analyses and observational studies suggest that rivaroxaban is associated with higher risk of bleeding when compared with apixaban (RR 2.14, 72,586 patients), dabigatran (RR 1.24, 67,102 patients), and edoxaban (RR 1.32, 71,683 patients).

CONCLUSIONS

Research on the long-term comparative effectiveness, safety, and effects on quality of life between rivaroxaban and other novel oral anticoagulants is urgently needed.

Real-world comparison of bleeding risks among non-valvular atrial fibrillation patients prescribed apixaban, dabigatran, or rivaroxaban

Limited real-world data are available regarding the comparative safety of non-vitamin K antagonist oral anticoagulants (NOACs). The objective of this retrospective claims observational cohort study was to compare the risk of bleeding among non-valvular atrial fibrillation (NVAF) patients prescribed apixaban, dabigatran, or rivaroxaban. NVAF patients aged ≥18 years with a 1-year baseline period were included if they were new initiators of NOACs or switched from warfarin to a NOAC. Cox proportional hazards modelling was used to estimate the adjusted hazard ratios of any bleeding, clinically relevant non-major (CRNM) bleeding, and major inpatient bleeding within 6 months of treatment initiation for rivaroxaban and dabigatran compared to apixaban. Among 60,227 eligible patients, 8,785 were prescribed apixaban, 20,963 dabigatran, and 30,529 rivaroxaban. Compared to dabigatran or rivaroxaban patients, apixaban patients were more likely to have greater proportions of baseline comorbidities and higher CHA₂DS₂-VASc and HAS-BLED scores. After adjusting for baseline clinical and demographic characteristics, patients prescribed rivaroxaban were more likely to experience any bleeding (HR: 1.35, 95% confidence interval [CI]: 1.26–1.45), CRNM bleeding (HR: 1.38, 95% CI: 1.27–1.49), and major inpatient bleeding (HR: 1.43, 95% CI: 1.17–1.74), compared to patients prescribed apixaban. Dabigatran patients had similar bleeding risks as apixaban patients. In conclusion, NVAF patients treated with rivaroxaban appeared to have an increased risk of any bleeding, CRNM bleeding, and major inpatient bleeding, compared to apixaban patients. There was no significant difference in any bleeding, CRNM bleeding, or inpatient major bleeding risks between patients treated with dabigatran and apixaban.