Adherence to Rivaroxaban, Dabigatran, and Apixaban for Stroke Prevention in Incident, Treatment-Naïve Nonvalvular Atrial Fibrillation

Utilization outcomes of direct oral anticoagulants in Medicare patients

OBJECTIVE

To compare the adherence, persistence, discontinuation and switching rates of direct oral anticoagulants (DOACs) for Medicare patients with non-valvular atrial fibrillation (NVAF) or venous thromboembolism (VTE).

METHODS

This was retrospective observational cohort study design. Medicare Part D claims files were used for the study duration (2015-2018). Inclusion-exclusion criteria were applied to identify the NVAF and VTE sample using dabigatran, rivaroxaban, apixaban, edoxaban and warfarin during the identification period (2016-2017). Outcomes of adherence, persistence, time to non-persistence and time to discontinuation were assessed in those who did not switch the index drug in the follow-up period (365 days from the index date). Switching rates were assessed in those who switched the index drug at least once in the aforementioned follow-up period. Descriptive statistics were conducted for all the outcomes, and comparisons were made using t-tests, chi-square, and ANOVA. Logistic regression was conducted to compare the odds of being adherent and the odds of switching in NVAF and VTE patient cohorts.

RESULTS

Of all the DOACs, patients with NVAF or VTE were most adherent to apixaban (PDC = 76.88). Among all the DOACs, non-persistence and discontinuation rates were highest for warfarin. Majority of the switches were reported from dabigatran to other DOAC and to apixaban from other DOAC. Despite the better utilization outcomes reported for apixaban users, Medicare plans covered rivaroxaban favorably. It was associated with the lowest mean amount paid by the patient (NVAF: $76; VTE: $59), and the highest mean amount paid by the plans (NVAF: $359; VTE: $326).

CONCLUSION

Medicare plans need to consider adherence, persistence, discontinuation and switching rates of DOACs to make the coverage decisions.

Percutaneous Left Atrial Appendage Occlusion Therapy: Evolution and Growing Evidence

Atrial fibrillation (AF) is the most common cardiac arrhythmia and if untreated, significantly increases both the risk of intracardiac thrombus formation and ischemic stroke. In patients with nonvalvular AF (NVAF), the left atrial appendage (LAA) has been estimated to be the source of thrombus development in 91% to 99% of cases. Consequently, oral anticoagulation (OAC) to provide stroke prevention has become the standard of care for most AF patients; however, OACs are associated with a risk of bleeding and their efficacy depends on optimal patient compliance. In terms of alternative approaches to preventing embolic events, surgical LAA excision was attempted as early as in the late 1940s in patients with valvular AF; LAA excision remains a recommendation in surgical guidelines for NVAF patients who need open-heart coronary bypass or valvular replacement/repair surgeries. However, due to its invasive nature surgical LAA intervention has limited clinical application in present cardiology practice. Percutaneous LAA occlusion (LAAO) is increasingly being performed as an alternative to OAC for stroke prevention; this is particularly the case in patients at increased bleeding risk. Substantial progress has been made in percutaneous LAAO therapy since its inception some twenty years ago. Herein we systematically review both the critical literature that led to the development of LAAO, and the increasing clinical evidence supporting the application of this treatment strategy in NVAF. To this end we focus on recently published critical evaluations of United States Food and Drug Administration (US FDA) and Conformité Européenne (Commercial Sale of Licensed Product in the EU) (CE-Mark) approved LAAO devices, summarize the current status of LAAO therapy, and discuss the future perspectives regarding the knowledge and technology gaps in this area by recognizing the potential contributions of many ongoing but likely transformative clinical trials.

Design and rationale of the mobile health intervention for rural atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is a highly morbid condition which requires long-term adherence to oral anticoagulation and may be associated with adverse quality of life and health care utilization. We developed a relational agent-an interactive smartphone-based intervention accessible regardless of digital or health literacy-to assist individuals residing in rural, Western Pennsylvania, with AF with chronic disease self-management.

METHODS

The "Mobile health intervention for rural atrial fibrillation" is a single center, parallel-arm randomized clinical trial for adults with AF funded by the National Institute of Health's National Heart, Lung, and Blood Institute to enroll 264 participants. All participants receive a smartphone with data plan: The intervention is a 4 month relational agent coupled with the AliveCor Kardia for heart rate and rhythm monitoring provided by smartphone, and the control a pre-installed, smartphone-based application for health-related information (WebMD). The study uses remote recruitment and engagement to enroll individuals who would otherwise be unlikely to participate in clinical research due to rurality. The primary outcome of the trial is adherence to oral anticoagulation, determined by proportion of days covered, as measured at 12 months. The secondary outcomes are quality of life, both AF-specific and general, and health care utilization. The study entails a baseline visit, a 4 month intervention phase, and 8 and 12 month follow-up visits.

CONCLUSIONS

This mobile health trial tests the effectiveness of a smartphone-based relational agent to improve clinical and patient-reported outcomes in rural-dwelling individuals.

Towards better reporting of the Proportion of Days Covered method in cardiovascular medication adherence: A scoping review and new tool TEN-SPIDERS

Although medication adherence is commonly measured in electronic datasets using the proportion of days covered (PDC), no standardized approach is used to calculate and report this measure. We conducted a scoping review to understand the approaches taken to calculate and report the PDC for cardiovascular medicines to develop improved guidance for researchers using this measure. After prespecifying methods in a registered protocol, we searched Ovid Medline, Embase, Scopus, CINAHL Plus and grey literature (1 July 2012 to 14 December 2020) for articles containing the terms “proportion of days covered” and “cardiovascular medicine”, or synonyms and subject headings. Of the 523 articles identified, 316 were reviewed in full and 76 were included (93% observational studies; 47% from the USA; 2 grey literature articles). In 45 articles (59%), the PDC was measured from the first dispensing/claim date. Good adherence was defined as 80% PDC in 61 articles, 56% of which contained a rationale for selecting this threshold. The following parameters, important for deriving the PDC, were often not reported/unclear: switching (53%), early refills (45%), in‐hospital supplies (45%), presupply (28%) and survival (7%). Of the 46 articles where dosing information was unavailable, 59% reported how doses were imputed. To improve the transparent and systematic reporting of the PDC, we propose the TEN‐SPIDERS tool, covering the following PDC parameters: Threshold, Eligibility criteria, Numerator and denominator, Survival, Presupply, In‐hospital supplies, Dosing, Early Refills, and Switching. Use of this tool will standardize reporting of the PDC to facilitate reliable comparisons of medication adherence estimates between studies.

Adherence to rivaroxaban for the treatment of venous thromboembolism-Results from the FIRST registry

BACKGROUND

Medication nonadherence can result in poor clinical outcomes and significant costs to health care providers. When treating venous thromboembolism (VTE), subtherapeutic anticoagulation may contribute to complications such as recurrent VTE or postthrombotic syndrome.

OBJECTIVES

To describe the extent, reasons for, and predictors of nonadherence to rivaroxaban for the treatment of VTE in clinical practice in the United Kingdom reported by participants of the FIRST registry.

PATIENTS/METHODS

The FIRST registry was an observational, multicenter registry reporting on the use of rivaroxaban in routine clinical practice. FIRST registry participants completed an adherence screening questionnaire during their treatment and follow-up.

RESULTS

In total, 1028 participants completed 1660 questionnaires over 2 years. One hundred thirteen of 1028 (11%) reported nonadherence at 28 days (interquartile range, 21-45). Reasons given for nonadherence at 1 month were forgetfulness (8.6% vs 74.7%; P < .001), carelessness (2.7% vs 27.3%; P < .001) or a change in routine (7.4% vs 25.5%; P < .001) reported by adherent and nonadherent participants, respectively. Older age (10-year increments) was the strongest predictor of good adherence (adjusted odds ratio, 1.21; 95% confidence interval, 1.06-1.39; 1 = adherent).

CONCLUSIONS

Overall adherence to rivaroxaban was high, and most nonadherence was unintentional. Identification of those at risk of nonadherence may reduce the risk of VTE recurrence and long-term complications.

Estimated Thresholds of Minimum Necessary Adherence for Effective Treatment with Direct Oral Anticoagulants - A Retrospective Cohort Study in Health Insurance Claims Data

BACKGROUND

An essential contribution regarding the prevention of thromboembolic events in patients with (non-valvular) atrial fibrillation (AF) is good adherence to direct oral anticoagulants (DOACs). However, it is an open question what "good" adherence means for DOACs or below which threshold non-adherence is clinically relevant for AF patients. Ultimately, such a classification could prevent strokes and associated costs through adjusted treatment regimens or supportive measures.

METHODS

We selected 10,092 AF patients from health insurance claims data between 2014 and 2018 who were issued a majority (at least half of the number) of maximum approved strength prescriptions of one of the following DOACs, namely rivaroxaban, apixaban, or dabigatran. Due to the limited sample size, the prescriptions of dabigatran had to be finally excluded for the cut-off analysis. DOAC adherence was calculated as the proportion of days covered (PDC) by dividing the days of theoretical use (days covered) of the drug by the duration in days of the observation interval. PDC cut-off values were derived from stroke risk as a function of continuous PDC values in time-to-event analyses and corresponding dose-response models. The influence of adherence-promoting interventions (targeted and untargeted) on the occurrence of strokes and related costs was then projected, considering intervention costs per patient.

RESULTS

The population had a mean age of 74.5 years and 50% were female. The median PDC was 0.79 ± 0.28 with a median follow-up time of 1218 days, in which 2% of all DOAC patients had a stroke. The adherence cut-offs for good adherence were identified at 0.78 for rivaroxaban and 0.8 for apixaban. Targeted interventions appeared to be far more cost-effective than untargeted interventions.

CONCLUSION

Clear adherence cut-offs enable healthcare professionals to identify patients with clinically relevant non-adherence. Interventions based on these cut-offs appear to be a promising means to optimize DOAC treatment.

Anti-FXa-IIa activity test in Asian and its potential role for drug adherence evaluation in patients with direct oral anticoagulants: a nationwide multi-center synchronization study

BACKGROUND

The data of anti-FXa-IIa activity detection in Asian population is insufficient, and its potential role for drug adherence evaluation in patients with direct oral anticoagulants (DOACs) remains unclear. This study carried out multi-center anti-FXa-IIa activity detection in Asian, aiming to explore its applicability in Asian population and find its role in adherence evaluation.

METHODS

We assessed patients' self-reported adherence using the Morisky, Green, and Levine Adherence Scale (MGLS) from six hospitals. Plasma samples were collected for peak and trough concentration determination, and anti-FXa-IIa chromogenic assay was conducted using rivaroxaban/dabigatran calibrators and controls. Multivariate logistic regression models, covariate adjustment and spearman's two-tailed test were conducted in the data analysis. This study had been registered in clinical trials (NCT03666962).

RESULTS

In total, 271 patients taking rivaroxaban (n=149) or dabigatran (n=122) were enrolled. Among the 271 patients assessed by MGLS questionnaire, 188 persons (69.4%) showed high adherence, 77 persons (28.4%) was in intermediate adherence group, and only 6 patients (2.2%) had low adherence. Patients are more adherent dosed once daily of rivaroxaban compared to twice daily of dabigatran: 75.6% vs. 63.6%. Anti-FXa-IIa activity had good linear correlation with routine coagulation indexes (P<0.001), but no significant association was found between drug adherence and anti-FXa-IIa activity (P>0.05).

CONCLUSIONS

This study confirms that anti-FXa-IIa activity detection based on target drug calibrations can be used as an effective index for pharmacodynamic evaluation in Asian population, but had limited value in drug adherence evaluation for DOACs. As the limited samples, these findings could serve as a hypothesis-generating effort, and should be validated in further studies with larger sample sizes.

Cost-effectiveness of rivaroxaban versus warfarin in non-valvular atrial fibrillation patients with chronic kidney disease in China

WHAT IS KNOWN AND OBJECTIVE

In non-valvular atrial fibrillation (NVAF) patients with chronic kidney disease (CKD), rivaroxaban was not inferior to warfarin in preventing stroke and systemic embolism. However, a comparative evaluation of the cost-effectiveness of rivaroxaban and warfarin therapies for NVAF patients at different renal function levels has not yet been reported, and this study aimed to estimate the cost-effectiveness of rivaroxaban compared with warfarin in Chinese NVAF patients with CKD.

METHODS

A Markov model was constructed to estimate quality-adjusted life years (QALYs) and lifetime costs associated with the use of rivaroxaban relative to warfarin in patients with NVAF at different estimated glomerular filtration rate (eGFR) levels as follows: 30 to <50, 50 to <80 and ≥80 mL/min. Input parameters were sourced from the clinical literature. Probabilistic sensitivity analyses were performed to assess model uncertainty.

RESULTS AND DISCUSSION

The incrementalQALYs with rivaroxaban was slightly increased by approximately 0.3 QALY as compared with that with warfarin in all the subgroups, resulting in an ICER of $9,736/QALY (eGFR, 30 to <50 mL/min), $9,758/QALY (50 to <80 mL/min) and $9,969/QALY (≥80 mL/min). The probabilistic sensitivity analysis suggested a chance of >80% that the ICER would be lower than the willingness-to-pay threshold of three times the GDP of China in 2019 in all the subgroups. Results were consistent even under the assumption of anticoagulant discontinuation after major bleeding events. The model was most sensitive to event-free-related utility and survival rates.

WHAT IS NEW AND CONCLUSION

The existing evidence supports the cost-effectiveness of rivaroxaban therapy as an alternative anticoagulant to warfarin for patients with NVAF at different renal function levels.

The Atrial Fibrillation Health Literacy Information Technology Trial: Pilot Trial of a Mobile Health App for Atrial Fibrillation

Background

Atrial fibrillation (AF) is a common arrhythmia that adversely affects health-related quality of life (HRQoL). We conducted a pilot trial of individuals with AF using a smartphone to provide a relational agent as well as rhythm monitoring. We employed our pilot to measure acceptability and adherence and to assess its effectiveness in improving HRQoL and adherence.

Objective

This study aims to measure acceptability and adherence and to assess its effectiveness to improve HRQoL and adherence.

Methods

Participants were recruited from ambulatory clinics and randomized to a 30-day intervention or usual care. We collected baseline characteristics and conducted baseline and 30-day assessments of HRQoL using the Atrial Fibrillation Effect on Quality of Life (AFEQT) measure and self-reported adherence to anticoagulation. The intervention consisted of a smartphone-based relational agent, which simulates face-to-face counseling and delivered content on AF education, adherence, and symptom monitoring with prompted rhythm monitoring. We compared differences in AFEQT and adherence at 30 days, adjusted for baseline values. We quantified participants’ use and acceptability of the intervention.

Results

A total of 120 participants were recruited and randomized (59 to control and 61 to intervention) to the pilot trial (mean age 72.1 years, SD 9.10; 62/120, 51.7% women). The control group had a 95% follow-up, and the intervention group had a 93% follow-up. The intervention group demonstrated significantly higher improvement in total AFEQT scores (adjusted mean difference 4.5; 95% CI 0.6-8.3; P=.03) and in daily activity (adjusted mean difference 7.1; 95% CI 1.8-12.4; P=.009) compared with the control between baseline and 30 days. The intervention group showed significantly improved self-reported adherence to anticoagulation therapy at 30 days (intervention 3.5%; control 23.2%; adjusted difference 16.6%; 95% CI 2.8%-30.4%; P<.001). Qualitative assessments of acceptability identified that participants found the relational agent useful, informative, and trustworthy.

Conclusions

Individuals randomized to a 30-day smartphone intervention with a relational agent and rhythm monitoring showed significant improvement in HRQoL and adherence. Participants had favorable acceptability of the intervention with both objective use and qualitative assessments of acceptability.

Adherence to oral anticoagulants among patients with atrial fibrillation: a systematic review and meta-analysis of observational studies

INTRODUCTION

Medications cannot exert their effect if not taken as prescribed by patients. Our objective was to summarise the observational evidence on adherence to oral anticoagulants (OACs) among patients with atrial fibrillation (AF).

METHODS

In March 2019, we systematically searched PubMed/Medline, Embase, CINAHL and PsycINFO (from inception) for observational studies measuring adherence, its determinants and impacts in patients with AF. Mean adherence measures and corresponding proportions of adherent patients were pooled using random effects models. Factors shown to be independently associated with adherence were extracted as well as the clinical and economic outcomes of adherence.

RESULTS

We included 30 studies. Pooled mean adherence scores of over half a million patients with AF 6 months and 1 year after therapy initiation were 77 (95% CI: 74-79) and 74 (68-79) out of 100, respectively. Drug-specific pooled mean adherence score at 6 months and 1 year were as follows: rivaroxaban: 78 (73-84) and 77 (69-86); apixaban: 77 (75-79) and 82 (74-89); dabigatran: 74 (69-79) and 75 (68-82), respectively. There was inadequate information on warfarin for inclusion in meta-analysis.Factors associated with increased adherence included: older age, higher stroke risk, once-daily regimen, history of hypertension, diabetes or stroke, concomitant cardiovascular medications, living in rural areas and being an experienced OAC user. Non-adherent patients were more likely to experience stroke and death, and incurred higher medical costs compared with patients with poor adherence.

CONCLUSIONS

Our findings show that up to 30% of patients with AF are non-adherent, suggesting an important therapeutic challenge in this patient population.

Association of Oral Anticoagulants and Verapamil or Diltiazem With Adverse Bleeding Events in Patients With Nonvalvular Atrial Fibrillation and Normal Kidney Function

IMPORTANCE

Direct oral anticoagulants (DOACs) are purported to have fewer drug-drug interactions than warfarin. However, potential interactions with coprescribed medications are still a safety concern. Verapamil hydrochloride and diltiazem hydrochloride are combined P-glycoprotein (P-gp) and CYP3A4 inhibitors and may be associated with increases in the risk of bleeding with DOACs.

OBJECTIVE

To evaluate the risk of bleeding with DOACs and verapamil or diltiazem using an active comparator design.

DESIGN, SETTING, AND PARTICIPANTS

A comparative effectiveness active comparator cohort study was conducted using US population-based data (2010-2015) analyzed between January 1 and July 15, 2019. Data were obtained on 48 442 patients with nonvalvular atrial fibrillation who had received an index prescription of dabigatran, rivaroxaban, or apixaban between October 19, 2010, through June 30, 2015, with final follow-up on October 1, 2015. Analysis was restricted to individuals with no history of kidney disease who were receiving standard doses of the DOACs.

EXPOSURES

Patients with initial prescriptions of DOACs who were receiving verapamil or diltiazem were compared with those receiving amlodipine or metoprolol.

MAIN OUTCOMES AND MEASURES

Overall and gastrointestinal major, moderate, and minor bleeding using primary or secondary diagnoses. Hazard ratios and 95% CIs were estimated using inverse probability of treatment weights in Cox proportional hazards regression models.

RESULTS

Of the 48 442 patients reviewed, analysis was conducted on 1764 patients receiving DOACs with verapamil or diltiazem compared with 3105 receiving amlodipine and 1793 patients receiving DOACs with verapamil or diltiazem compared with 3224 receiving metoprolol. Depending on the comparison, approximately 60% of the cohort were younger than 65 years and male, which differed by treatment group. Rivaroxaban and apixaban were not associated with increased rates of bleeding for patients receiving verapamil or diltiazem compared with those receiving amlodipine or metoprolol. Among patients receiving dabigatran etexilate, the overall bleeding rate was 52% higher (hazard ratio, 1.52; 95% CI, 1.05-2.20) with verapamil or diltiazem vs amlodipine and 43% higher (hazard ratio, 1.43; 95% CI, 1.02-2.00) vs metoprolol. Bleeding rates for dabigatran with verapamil or diltiazem were higher overall for other bleeding types (244.9 vs 158.4 per 1000 person-years; adjusted hazard ratios of overall GI bleeding: 2.16; 95% CI, 1.30-3.60; minor bleeding: 1.56; 95% CI, 1.07-2.27; and minor GI bleeding: 2.16; 95% CI, 1.29-3.63). Sensitivity analyses showed consistent results for dabigatran when used with verapamil and diltiazem, with magnitudes ranging from 50% to 100% increased hazard rates and no significant results for apixaban or rivaroxaban.

CONCLUSIONS AND RELEVANCE

Current US prescribing information only recommends prescribing changes with dabigatran and P-gp inhibitors with lower kidney function. This study found increased bleeding risk associated with dabigatran when used concomitantly with the P-gp inhibitors verapamil and diltiazem in individuals with normal kidney function. Clinicians and patients may need to consider these drug-drug interactions when choosing oral anticoagulation.

Rivaroxaban Versus Apixaban for Stroke Prevention in Atrial Fibrillation

Background:

The comparative effectiveness of non-vitamin K antagonist oral anticoagulants (NOACs) is uncertain, as they have not been compared directly in randomized trials. Previous observational comparisons of NOACs are likely to be biased by unmeasured confounders. We sought to compare the efficacy and safety of rivaroxaban and apixaban for stroke prevention in patients with atrial fibrillation (AF), using practice variation in preference for NOAC as an instrumental variable.

Methods and Results:

Patients started on apixaban or rivaroxaban after newly diagnosed AF were identified using Danish nationwide registries. Patients were categorized according to facility preferences for type of NOAC, independent of actual treatment, measured as fraction of the prior 20 patients with AF initiated on rivaroxaban in the same facility. Facility preference for NOAC was used as an instrumental variable. The occurrence of stroke/thromboembolism, major bleeding, myocardial infarction, and all-cause mortality over 2 years of follow-up were investigated using adjusted Cox regressions. We analyzed 6264 patients with AF initiated on rivaroxaban or apixaban. NOAC preference was strongly related to actual choice of treatment but not associated with any other measured baseline characteristics. Patients treated in facilities that had preference for rivaroxaban had more major bleeding: compared with patients treated in facilities that used rivaroxaban in 0% to 20% of cases, the adjusted hazard ratio for bleeding was 1.06 when treated in a facility with 25% to 40% use; 1.41 with 45% to 60% use; 1.51 with 65% to 80% use; and 1.81 with 0% to 100% use ( P trend =0.01). Higher facility preference for rivaroxaban was not significantly associated with increased risk of stroke/thromboembolism ( P trend =0.06), myocardial infarction ( P trend =0.65), or all-cause mortality ( P trend =0.89). When we used the instrumental variable to model the causal relationship between choice of NOAC and major bleeding, relative risk with rivaroxaban was 1.89 (95% CI, 1.06–2.72) compared with apixaban.

Conclusions:

Using instrumental variable estimation in a cohort of patients with AF, rivaroxaban was associated with higher risk of major bleeding compared with apixaban. No significant associations to other outcomes were found in main analyses.

Impact of medication nonadherence on stroke recurrence and mortality in patients after first-ever ischemic stroke: Insights from registry data in Singapore

PURPOSE

This retrospective cohort study aims to examine adherence to secondary stroke preventive medications and their association with risk of stroke recurrence and mortality in patients after first-ever ischemic stroke.

METHODS

Using data from the National Healthcare Group and Singapore Stroke Registry, patients with first-ever ischemic stroke between 2010 and 2014 were included, and categorized based on antithrombotic or statin adherence using the proportion of days covered: high (≥75%), intermediate (50%-74%), low (25%-49%), and very low (<25%). The primary outcome was first recurrent ischemic stroke within a year after hospital discharge, while the secondary composite outcomes were (a) stroke recurrence and all-cause mortality and (b) stroke recurrence and cardiovascular mortality. The Cox proportional hazard model was used to examine the association between medication adherence and outcomes. Adjusted hazard ratios (aHRs) and the corresponding 95% confidence intervals (CIs) were reported.

RESULTS

Among ischemic stroke patients prescribed with antithrombotics (n = 1139) or statins (n = 1160) at hospital discharge, about one-third were highly adherent to their medications. Patients with lower medication adherence tended to be younger, were admitted to private ward classes, and were without hypertension. Compared with the patients with high medication adherence, the risk of stroke recurrence was higher in patients with very low antithrombotic (aHR = 4.65; 95% CI: 1.45-14.89) or statin (aHR = 3.44; 95% CI: 0.93-12.74) adherence. Similar findings were observed for the secondary outcomes.

CONCLUSIONS

Poor adherence to antithrombotic and statin treatment increases the risk of recurrent stroke and mortality in patients after first-ever ischemic stroke. Further measures are needed to improve medication adherence among stroke survivors.

[How to maintain an adherence to oral anticoagulant in a patient with atrial fibrillation?]

Less onerous, compared with warfarin, treatment with direct oral anticoagulants (DOA) can lead to better adherence to treatment of patients with atrial fibrillation (AF). However, in a certain number of patients with AF, who were recommended by DOA, cardioembolic stroke recurs, which is largely due to the patients' failure to comply with medical recommendations. The appointment of DOA as first-line drugs does not guarantee a high adherence of patients with non-valvular AF. For elderly and old patients with AF and numerous comorbidities, the proposal of a simpler pharmacotherapy regimen is especially important. In a number of large modern studies performed in clinical practice, high adherence to rivaroxaban therapy has been established, which may be a result of taking this DOA 1 time per day, its safety and effectiveness.

Patient-Reported Satisfaction and Study Drug Discontinuation: Post-Hoc Analysis of Findings from ROCKET AF

INTRODUCTION

Patient-reported outcomes (PROs) and satisfaction endpoints are increasingly important in clinical trials and may be associated with treatment adherence. In this post hoc substudy from ROCKET AF, we examined whether patient-reported satisfaction was associated with study drug discontinuation.

METHODS

ROCKET AF (n = 14,264) compared rivaroxaban with warfarin for prevention of stroke and systemic embolism in patients with atrial fibrillation. We analyzed treatment satisfaction scores: the Anti-Clot Treatment Scale (ACTS) and Treatment Satisfaction Questionnaire for Medication version II (TSQM II). We compared satisfaction with study drug between the two treatment arms, and examined the association between satisfaction and patient-driven study drug discontinuation (stopping study drug due to withdrawal of consent, noncompliance, or loss to follow-up).

RESULTS

A total of 1577 (11%) patients participated in the Patient Satisfaction substudy; 1181 (8.3%) completed both the ACTS and TSQM II 4 weeks after starting study drug. Patients receiving rivaroxaban did not experience significant differences in satisfaction compared with those receiving warfarin. During a median follow-up of 1.6 years, 448 premature study drug discontinuations occurred (213 rivaroxaban group; 235 warfarin group), of which 116 (26%) were patient-driven (52 [24%] rivaroxaban group; 64 [27%] warfarin group). No significant differences were observed between satisfaction level and rates of patient-driven study drug discontinuation.

CONCLUSIONS

Study drug satisfaction did not predict rate of study drug discontinuation. No significant difference was observed between satisfaction with warfarin and rivaroxaban, as expected given the double-blind trial design. Although these results are negative, the importance of PRO data will only increase, and these analyses may inform future studies that explore the relationship between drug-satisfaction PROs, adherence, and clinical outcomes. CLINICALTRIALS.GOV: NCT00403767.

FUNDING

The ROCKET AF trial was funded by Johnson & Johnson and Bayer.

Trajectories of Oral Anticoagulation Adherence Among Medicare Beneficiaries Newly Diagnosed With Atrial Fibrillation

Background

Only 50% of atrial fibrillation (AF) patients recommended for oral anticoagulation (OAC) use these medications, and less than half of them adhere to OAC. In a cohort of Medicare beneficiaries newly diagnosed with AF, we identified groups of patients with similar trajectories of OAC use and adherence, and evaluated patient characteristics affecting group membership.

Methods and Results

We selected continuously enrolled Medicare Part D beneficiaries with first AF diagnosis in 2014 to 2015 (n=34 898). We calculated the proportion of days covered with OAC over the first 12 months after diagnosis and identified OAC adherence trajectories using group‐based trajectory models. We constructed multinomial logistic regression models to evaluate how demographics, system‐level factors, and clinical characteristics were associated with group membership. We identified 4 trajectories of OAC adherence: patients who never used OAC (43.8%), late OAC initiators (7.6%), early OAC discontinuers (8.9%), and continuously adherent patients (40.1%). Predictors such as sex, black race, residence in the South, or HAS‐BLED score were associated with not only OAC use, but also the timing of initiation and the likelihood of discontinuation. For example, HAS‐BLED score ≥4 was associated with a higher likelihood of not using OAC (odds ratio 1.35; 95% CI, 1.14–1.62), of late initiation (1.55; 95% CI, 1.11–2.05), and of early discontinuation (odds ratio 1.35; 95% CI, 1.01–1.84).

Conclusions

We identified 4 distinct trajectories of OAC adherence after first AF diagnosis, with <45% of newly diagnosed AF patients belonging to the trajectory group characterized by continuous OAC adherence. Trajectories were associated not only with demographic and clinical characteristics but also with regional factors.

Modeling the impact of real-world adherence to once-daily (QD) versus twice-daily (BID) non-vitamin K antagonist oral anticoagulants on stroke and major bleeding events among non-valvular atrial fibrillation patients

OBJECTIVES

To estimate the real-world (RW) impact of adherence to once-daily (QD: rivaroxaban and edoxaban) and twice-daily (BID: apixaban and dabigatran) non-vitamin K antagonist (NOACs) on the risk of stroke and major bleeding (MB) among non-valvular atrial fibrillation (NVAF) patients.

METHODS

First, claims from the Optum Clinformatics Data Mart database (July 2012-December 2016) were analyzed. Adult NVAF patients with ≥2 NOAC dispensings (index date) were included. The relationship between NOAC adherence (proportion of days covered ≥80%) and stroke/MB 1-year post-index was evaluated using adjusted Cox proportional hazards models. Second, the natural logarithm of hazard ratios (HRs) was multiplied to a literature-derived mean adherence difference between QD and BID NOACs yielding stroke and MB rates. Third, these rates were multiplied by 1-year Kaplan-Meier rates of stroke and MB which yielded the number of strokes prevented and MBs caused. Annual cost savings were evaluated using literature-based stroke ($81,414/patient) and MB ($63,905/patient) cost estimates.

RESULTS

In total, 54,280 patients were included. HRs for adherent vs non-adherent patients were 0.67 (p < .001) for stroke and 1.09 (p = .179) for MB. The claims-derived 1-year Kaplan-Meier rates were 3.0% and 3.4% for strokes and MBs, respectively. For 100,000 AF patients, 64 strokes were prevented (p < .001), and a non-significant number of MBs (n = 15, p < .191) were caused by QD vs BID NOACs annually, which leads to cost savings estimated at $58 million for QD NOACs.

CONCLUSION

QD NOACs prevented a significant number of strokes and caused no significant increase in MBs compared to BID NOACs, which leads to significant net cost savings for NVAF patients in the US.

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.

The Role of Adherence Thresholds for Development and Performance Aspects of a Prediction Model for Direct Oral Anticoagulation Adherence

Patients who do not sufficiently adhere to their dosing regimens will, ultimately, do not get the full benefit of their medication. For example, if direct oral anticoagulants (DOAC) are not taken continuously, an intervention to improve adherence or maintain persistence will show direct effects on clinical outcomes. Usually, adherent patients are defined by taking ≥80% of their medication. The resulting binary adherence status from this threshold can as well be used for predictive classification. Thus, the threshold can determine the prediction model’s performance to identify patients at risk for poor adherence by this binary adherence status. In this perspective, we propose a plan for model development and performance considering the threshold’s role. Concerning development demands, we extracted predictors from a systematic literature search on DOAC adherence to be used as a core set of candidate predictors. Independently, we investigated how well a future model would technically have to perform by modeling drug intake and thromboembolic events based on a rivaroxaban pharmacokinetic-pharmacodynamic model. Using this simulation framework for different thresholds, we projected the impact of an imperfectly predicted adherence status on the event risk, and how imperfect sensitivity and specificity affect the cost balance if a supporting intervention was offered to patients classified as non-adherent. Our simulation results suggest applying a rather high threshold (90%) for discrimination between patients at low or high risk for non-adherence by a prediction model in order to assure cost-efficient implementation.

Estimating Adherence Based on Prescription or Dispensation Information: Impact on Thresholds and Outcomes. A Real-World Study With Atrial Fibrillation Patients Treated With Oral Anticoagulants in Spain

Objective: To estimate drug exposure, Proportion of Days Covered (PDC) and percentage of patients with PDC ≥ 80% from a cohort of atrial fibrillation patients initiating oral anticoagulant (OAC) treatment. We employed three different approaches to estimate PDC, using either data from prescription and dispensing (PD cohort) or two common designs based on dispensing information only, requiring at least one (D1) or at least two (D2) refills for inclusion in the cohorts. Finally, we assessed the impact of adherence on health outcomes according to each method. Methods: Population-based retrospective cohort of all patients with Non Valvular Atrial Fibrillation (NVAF), who were newly prescribed acenocoumarol, apixaban, dabigatran or rivaroxaban from November 2011 to December 2015 in the region of Valencia (Spain). Patients were followed for 12 months to assess adherence using three different approaches (PD, D1 and D2 cohorts). To analyze the relationship between adherence (PDC ≥ 80) defined according to each method of calculation and health outcomes (death for any cause, stroke or bleeding) Cox regression models were used. For the identification of clinical events patients were followed from the end of the adherence assessment period to the end of the available follow-up period. Results: PD cohort included all patients with an OAC prescription (n = 38,802), D1 cohort excluded fully non-adherent patients (n = 265) and D2 cohort also excluded patients without two refills separated by 180 days (n = 2,614). PDC ≥ 80% ranged from 94% in the PD cohort to 75% in the D1 cohort. Drug exposure among adherent (PDC ≥ 80%) and non-adherent (PDC < 80%) patients was different between cohorts. In adjusted analysis, high adherence was associated with a reduced risk of death [Hazard Ratio (HR): from 0.82 to 0.86] and (except in the PD cohort) the risk for ischemic stroke (HR: from 0.61 to 0.64) without increasing the risk of bleeding. Conclusion: Common approaches to assess adherence using measures based on days' supply exclude groups of non-adherent patients and, also, misattribute periods of doctors' discontinuation to patient non-adherence, misestimating adherence overall. Physician-initiated discontinuation is a major contributor to reduced OAC exposure. When using the PDC80 threshold, very different groups of patients may be classified as adherent or non-adherent depending on the method used for the calculation of days' supply measures. High adherence and high exposure to OAC treatment in NVAF patients is associated with better health outcomes.

Pharmacokinetics of new oral anticoagulants: implications for use in routine care

INTRODUCTION

Since 2008, new oral anticoagulants (NOACs) have been approved for the prevention of venous thromboembolism (VTE) in patients receiving hip or knee replacement surgery, prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation (NVAF), treatment of deep vein thrombosis (DVT), and pulmonary embolism (PE). Premarketing randomized clinical trials (RCTs) of NOACs demonstrated their non-inferiority in terms of efficacy vs. warfarin (traditional oral anticoagulant - TOA), with lower risk of serious adverse drug reactions, especially cerebral hemorrhages. In clinical practice, pharmacokinetic aspects of NOACs have to be carefully taken into account to optimize the benefit-risk profile of these drugs. Areas covered: An overview of major issues related to pharmacokinetics of NOACs, such as drug-drug interactions, over- and underdosage in special populations (e.g. elderly, underweight, and chronic kidney disease patients), and impact on adherence and persistence to NOACs therapy and ultimately clinical outcomes in real-world setting, is provided. Expert opinion: NOACs have been proven to be a better option than traditional anticoagulants due to better tolerability and ease of use. However, given specific pharmacokinetic characteristics, NOAC therapy has to be carefully tailored and monitored in relation to patient characteristics with the final goal of maximizing benefits and minimizing risks.

Anticoagulant plus antiplatelet therapy for atrial fibrillation : Cost-utility of combination therapy with non-vitamin K oral anticoagulants vs. warfarin

BACKGROUND

Emerging evidence indicates combination therapy with anticoagulants and antiplatelet agents for atrial fibrillation (AF) will be increasingly required. Numerous studies compare the efficacy and cost-effectiveness of anticoagulation alone in AF, i. e., non-vitamin K oral anticoagulants (NOACs) vs. warfarin. However, the addition of antiplatelet agents with their potential for decreasing thromboembolic stroke counter-balanced by an increased bleeding risk has received less attention. Thus, we evaluated the cost-utility of this combination therapy.

METHOD AND RESULTS

We obtained event estimates from our recent meta-analysis of four randomized clinical trials designed to compare NOACs with warfarin in patients with AF. We examined patient subgroups within each trial that received antiplatelet therapy in addition to anticoagulation. Utilities were derived from the literature and cost estimates from the German health-care system. A decision tree was constructed and populated with these parameters. We used a 1-year time horizon because combination therapy is not recommended beyond this time. We calculated the incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY). The derived ICER was 13,168.50 € per QALY. NOAC prices exerted considerable influence on the calculation. Nevertheless, there is potential for ICER shifts in favor of warfarin, e.g., if warfarin-mediated anticoagulation control is improved and thereby adverse events decrease. Conversely, if NOAC adherence decreases, adverse events could increase.

CONCLUSION

The derived ICER was 13,168.50 € per QALY, consistent with NOACs being cost-effective vs. warfarin when anticoagulation is used with antiplatelet agents. Nevertheless, country-, practice-, and patient-related factors influence the ICER. Our cost-utility calculation should be used a starting point for decision-making.

Impact of medication adherence on risk of ischemic stroke, major bleeding and deep vein thrombosis in atrial fibrillation patients using novel oral anticoagulants

OBJECTIVES

Our study examined the impact of adherence to novel oral anticoagulants [NOACs - dabigatran and rivaroxaban] on ischemic-stroke (IS), major-bleeding (MB), deep-vein-thrombosis and pulmonary-embolism (DVTPE) risk in a large, nationwide, propensity-matched sample.

METHODS

A retrospective cohort study utilized data from a US commercial managed-care database (2010-2012). Adult patients with ≥1 diagnosis of atrial fibrillation/flutter (ICD-9 427.31/32), >1 prescription of NOACs and CHA₂DS₂-VASc score ≥1 were included. Patients were categorized as adherent versus nonadherent (using proportion of days covered [PDC ≥80%]) based on their NOAC use up to 6 months and those continued its use up to 12 months. The patients were matched using propensity score (based on inverse probability treatment weighting) and the risk of IS, MB, DVTPE outcomes was evaluated for the matched cohorts' post-adherence (exposure) assessment using multivariable Cox regression.

RESULTS

A total of 3,629 and 1,946 patients with at least 6 and 12 months of NOAC use were included. Based on a PDC threshold of ≥80%, adherence rates at 6 and 12 month usage were 77% and 76%, respectively. Patients with lowest adherence were from the South, had low stroke risk and EPO/HMO insurance. Using Cox models with matched cohorts, nonadherence within the first 6 months' use was significantly associated with higher risk of IS and DVTPE (IS: hazard ratio [HR] = 1.82, p = .002; DVTPE: HR = 2.12, p = .010) and the risk increased with nonadherence for the prolonged period of 12 months' use (IS: HR = 2.08, p = .022; DVTPE: HR = 5.39, p = .003). The risk of MB was not different (p > .05) between adherent and nonadherent groups for both 6 month and 12 month cohorts.

CONCLUSION

Adherence to NOACs for both 6 months and prolonged use (up to 12 months) was associated with a reduction in IS and DVTPE risk, but did not substantially increase risk of MB. Further studies on newer, individual NOACs and older populations are warranted.

Safety of once- or twice-daily dosing of non-vitamin K antagonist oral anticoagulants (NOACs) in patients with nonvalvular atrial fibrillation: A NOAC-TR study

Once-daily dosing of non-vitamin K antagonist oral anticoagulants (NOACs) may increase patient adherence to treatment but may also be associated with a higher risk of bleeding. In this study, we investigated the adherence to once- or twice-daily dosing of NOACs and the risk of bleeding in nonvalvular atrial fibrillation (NVAF) patients. This multicenter cross-sectional study, conducted between 1 September 2015 and 28 February 2016, included 2214 patients receiving NOACs for at least 3 months, due to NVAF. Patients receiving once-daily or twice-daily NOAC doses were 1:1 propensity score matched for baseline demographic characteristics and the presence of other diseases. The medication adherence was assessed by the 8-item Morisky Medication Adherence Scale. Risk factors were investigated in relation to minor and major bleeding. The mean age of patients was 71 ± 10 years, and 53% of the patients were women. The medication adherence was lower in patients receiving twice-daily NOAC doses compared to once-daily-dose group (47% versus 53%, p = 0.001), and there was no difference between the groups in terms of minor (15% versus 16%, p = 0.292) and major bleeding (3% versus 3%, p = 0.796). Independent risk factors for bleeding were non-adherence to medication (OR: 1.62, 95% CI: 1.23-2.14, p = 0.001), presence of 3 or more other diseases (OR: 10.3, 95% CI: 5.3-20.3, p < 0.001), and HAS-BLED (Hypertension, Abnormal renal and liver function, Stroke, Bleeding, Labile INR, Elderly, Drugs or alcohol) score (OR: 4.84, 95% CI: 4.04-5.8, p < 0.001). In summary, the once-daily dose of NOACs was associated with increased patient adherence to medication, while it was not associated with bleeding complications.

Real-World Health Care Costs Based on Medication Adherence and Risk of Stroke and Bleeding in Patients Treated with Novel Anticoagulant Therapy

BACKGROUND

With the lack of real-world evidence, the challenge for drug reimbursement policy decision makers is to understand medication adherence behavior among users of novel oral anticoagulants (NOACs) and its effect on overall cost savings. No study has examined and quantified the burden of cost in high-risk patients taking NOAC therapy.

OBJECTIVE

To examine the association of cost with adherence, comorbidity, and risk of stroke and bleeding in patients taking NOACs (rivaroxaban and dabigatran).

METHODS

A retrospective cohort study used deidentified data from a commercial managed care database affiliated with Optum Clinformatics Data Mart (January 1, 2010-December 31, 2012). Patients aged 18 years and older with ≥ 1 diagnosis of atrial fibrillation/flutter, > 1 NOAC prescription, 6-month pre-index and 12-month post-index continuous enrollment, and CHA₂DS₂-VASc score ≥ 1 were included. Adherence was calculated using proportion of days covered (PDC ≥ 80%) over an assessment period of 3, 6, and 12 months and compared based on level of comorbidity, stroke, and bleeding risk. The adjusted annual health care costs per patient (drug, medical, and total) were calculated using multivariable gamma regression controlling for demographic and clinical characteristics and compared across groups based on adherence over 12 months, baseline level of comorbidity, and risk of stroke and bleeding.

RESULTS

Of 25,120 NOAC patients, 2,981 patients were included in the final cohort. Based on a PDC threshold of ≥ 80%, the adherence rate over 3, 6, and 12 months was 72%, 65%, and 54%, respectively. For all time periods, the level of adherence significantly increased (P < 0.001), with an increase in stroke risk (based on CHA₂DS₂VASc scores of 1, 2-3, and 4+); comorbidity (Charlson Comorbidity Index scores of 0, 1-2, and 3+); and risk of bleeding (HAS-BLED scores of 0-1, 2, and 3+). Adjusted all-cause total cost calculated for a 12-month period was significantly lower ($29,742 vs. $33,609) among adherent versus nonadherent users. Drug cost was higher ($5,595 vs. $2,233) among adherent versus nonadherent patients but was offset by lower medical costs ($23,544 vs. $30,485) costs. The overall cost significantly increased for patients with a high risk of bleeding and a high level of comorbidity.

CONCLUSIONS

Adherence to NOAC therapy led to a reduction in overall health care cost, since higher drug costs were offset by lower medical (inpatient and outpatient) costs among adherent patients. Cost information based on adherence and risk of stroke and bleeding can help formulary decision makers to assess risk-benefit and help clinicians in developing interventions to reduce patient burden.

DISCLOSURES

Funding to acquire the data source was provided by the University of Rhode Island College of Pharmacy, Kingston, to support PhD dissertation work. Deshpande is currently an employee of Pharmerit International.

Safety and Efficacy of Novel Oral Anticoagulants Versus Warfarin in Medicare Beneficiaries With Atrial Fibrillation and Valvular Heart Disease

Background

We examined a large community‐based sample of patients with atrial fibrillation (AF) and valvular heart disease (VHD) (excluding prosthetic valves) with a goal to compare outcomes among patients with AF, with and without VHD, taking warfarin, dabigatran, and rivaroxaban.

Methods and Results

We identified Medicare beneficiaries enrolled in Medicare Part D benefit plan from 2011 to 2013 with newly diagnosed AF (18 137 patients with VHD [dabigatran, 1979; rivaroxaban, 2027; warfarin, 14 131] and 85 596 patients without VHD [dabigatran, 13 522; rivaroxaban, 14 257; warfarin, 57 817]). Primary outcomes of all‐cause mortality, ischemic strokes, major bleeding, and myocardial infarction were compared across the 3 anticoagulants using 3‐way propensity‐matched samples. After propensity matching, a total of 5871 patients with VHD and 40 221 patients without VHD and AF were studied. Both dabigatran and rivaroxaban were associated with significantly lower risk of death in patients with VHD with AF (dabigatran versus warfarin: hazard ratio, 0.71; 95% confidence interval, 0.52–0.98; P=0.038; rivaroxaban versus warfarin: hazard ratio, 0.68; 95% confidence interval, 0.49–0.95; P=0.022). Nongastrointestinal bleeding was significantly reduced with dabigatran and rivaroxaban versus warfarin in those with VHD (dabigatran versus warfarin: hazard ratio, 0.17; 95% confidence interval, 0.06–0.49; P=0.001; rivaroxaban versus warfarin: hazard ratio, 0.37; 95% confidence interval, 0.17–0.84; P=0.017). Ischemic stroke and gastrointestinal bleeding rates did not differ between rivaroxaban, dabigatran, and warfarin in patients with VHD. The effects of the 3 anticoagulants on outcomes were comparable in patients with and without VHD and with AF.

Conclusions

In this cohort of Medicare beneficiaries with VHD (excluding patients with prosthetic valves) and new‐onset AF between 2011 and 2013, novel oral non–vitamin K anticoagulants were safe and effective options for prevention of systemic thromboembolism.

Comparison of claims vs patient-reported adherence measures and associated outcomes among patients with nonvalvular atrial fibrillation using oral anticoagulant therapy

OBJECTIVE

To compare oral anticoagulant (OAC) adherence among patients with nonvalvular atrial fibrillation (NVAF) using patient-reported and claims-based measures, and to evaluate the effect of OAC adherence on health care costs and patient satisfaction with OAC therapy.

METHODS

This was a hybrid US observational study consisting of a longitudinal cohort survey followed by linkage and analysis of respondents' administrative claims data. Patients with NVAF receiving warfarin, dabigatran, rivaroxaban, or apixaban completed an initial survey and follow-up surveys at 4, 8, and 12 months. Patient-reported adherence was measured at each survey by Morisky Medication Adherence Scale (MMAS-8) and pharmacy claims-determined adherence by the proportion of days covered (PDC) for the 12-month period following the initial survey date; adherence was defined as MMAS-8 score =8 and PDC ≥80%. Patient satisfaction with OAC therapy was assessed by the Duke Anticoagulation Satisfaction Scale (DASS).

RESULTS

Overall, 675 patients completed at least the initial survey (warfarin, n=271; dabigatran, n=266; rivaroxaban, n=128; apixaban, n=10). Fewer than half (47.9%) were PDC adherent, 37.2% were MMAS-8 adherent, and 19.4% were adherent by both measures. Total medical costs of PDC-adherent patients were significantly lower vs PDC-nonadherent patients (US$640 vs $993 per-patient per-month, respectively, p<0.05). MMAS-8-adherent patients reported higher treatment satisfaction; total DASS score was significantly lower among MMAS-8-adherent than MMAS-8-nonadherent patients (37.3 vs 42.9, respectively, p<0.001).

CONCLUSION

Using claims-based or patient-reported methods to measure OAC adherence may lead to different results when assessing impact on health care costs and satisfaction with anticoagulation medication. These results underscore the importance of considering both claims-based and patient-reported measures when evaluating treatment adherence in real-world settings.

The Atrial Fibrillation Health Literacy Information Technology System: Pilot Assessment

Background

Atrial fibrillation (AF) is a highly prevalent heart rhythm condition that has significant associated morbidity and requires chronic treatment. Mobile health (mHealth) technologies have the potential to enhance multiple aspects of AF care, including education, monitoring of symptoms, and encouraging and tracking medication adherence. We have previously implemented and tested relational agents to improve outcomes in chronic disease and sought to develop a smartphone-based relational agent for improving patient-centered outcomes in AF.

Objective

The objective of this study was to pilot a smartphone-based relational agent as preparation for a randomized clinical trial, the Atrial Fibrillation Health Literacy Information Technology Trial (AF-LITT).

Methods

We developed the relational agent for use by a smartphone consistent with our prior approaches. We programmed the relational agent as a computer-animated agent to simulate a face-to-face conversation and to serve as a health counselor or coach specific to AF. Relational agent’s dialogue content, informed by a review of literature, focused on patient-centered domains and qualitative interviews with patients with AF, encompassed AF education, common symptoms, adherence challenges, and patient activation. We established that the content was accessible to individuals with limited health or computer literacy. Relational agent content coordinated with use of the smartphone AliveCor Kardia heart rate and rhythm monitor. Participants (N=31) were recruited as a convenience cohort from ambulatory clinical sites and instructed to use the relational agent and Kardia for 30 days. We collected demographic, social, and clinical characteristics and conducted baseline and 30-day assessments of health-related quality of life (HRQoL) with the Atrial Fibrillation Effect on Quality of life (AFEQT) measure; self-reported medication adherence with the Morisky 8-item Medication Adherence Scale (MMAS-8); and patient activation with the Patient Activation Measure (PAM).

Results

Participants (mean age 68 [SD 11]; 39% [12/31] women) used the relational agent for an average 17.8 (SD 10.0) days. The mean number of independent log-ins was 19.6 (SD 10.7), with a median of 20 times over 30 days. The mean number of Kardia uses was 26.5 (SD 5.9), and participants using Kardia were in AF for 14.3 (SD 11.0) days. AFEQT scores improved significantly from 64.5 (SD 22.9) at baseline to 76.3 (SD 19.4) units at 30 days (P<.01). We observed marginal but statistically significant improvement in self-reported medication adherence (baseline: 7.3 [SD 0.9], 30 days: 7.7 [SD 0.5]; P=.01). Assessments of acceptability identified that most of the participants found the relational agent useful, informative, and trustworthy.

Conclusions

We piloted a 30-day smartphone-based intervention that combined a relational agent with dedicated content for AF alongside Kardia heart rate and rhythm monitoring. Pilot participants had favorable improvements in HRQoL and self-reported medication adherence, as well as positive responses to the intervention. These data will guide a larger, enhanced randomized trial implementing the smartphone relational agent and the Kardia monitor system.

Comparison of the Effectiveness and Safety of Apixaban, Dabigatran, Rivaroxaban, and Warfarin in Newly Diagnosed Atrial Fibrillation

No studies have performed direct pairwise comparisons of the effectiveness and safety of warfarin and the new oral anticoagulants (NOACs) apixaban, dabigatran, and rivaroxaban. Using 2013 to 2014 claims from a 5% random sample of Medicare beneficiaries, we identified patients newly diagnosed with atrial fibrillation who initiated apixaban, dabigatran, rivaroxaban, warfarin, or no oral anticoagulation therapy in 2013 to 2014. Outcomes included the composite of ischemic stroke, systemic embolism (SE) and death, any bleeding event, gastrointestinal bleeding, intracranial bleeding, and treatment persistence. We constructed Cox proportional hazard models to compare outcomes between each pair of treatment groups. The composite risk of ischemic stroke, SE, and death was lower for NOACs than for warfarin: hazard ratio (HR) 0.86, 95% confidence interval (CI) 0.76 to 0.98 for apixaban; 0.73, 95% CI 0.63 to 0.86 for dabigatran; and 0.82, 95% CI 0.75 to 0.89 for rivaroxaban, all compared with warfarin. There were no differences in effectiveness across NOACs. The risk of any bleeding was lower with apixaban than with warfarin, but higher with rivaroxaban than with warfarin. Apixaban (HR 0.69, 95% CI 0.60 to 0.79) and dabigatran (HR 0.79, 95% CI 0.69 to 0.92) were associated with lower bleeding risk than rivaroxaban. Treatment persistence was highest for apixaban (82%), and lowest for dabigatran and warfarin (64%) (p value <0.001). Compared with warfarin, NOACs are more effective in preventing stroke but their risk of bleeding varies, with rivaroxaban having higher risk than warfarin. Altogether, apixaban had the most favorable effectiveness, safety, and persistence profile.

Oral anticoagulant persistence in patients with non-valvular atrial fibrillation: A cohort study using primary care data in Germany

This study examined characteristics and treatment persistence among patients prescribed oral anticoagulants (OACs) for stroke prevention in non-valvular atrial fibrillation (NVAF). We identified 15,244 patients (51.8% male, 72.7% aged ≥70) with NVAF and no prior OAC therapy who were prescribed apixaban (n = 1,303), rivaroxaban (n = 5,742), dabigatran (n = 1,622) or vitamin-K antagonists (VKAs, n = 6,577) between 1-Dec-2012 and 31-Oct-2014 in German primary care (IMS® Disease Analyzer). We compared OAC persistence using Cox regression over patients’ entire follow-up and using a data-driven time-partitioned approach (before/after 100 days) to handle non-proportional hazards. History of stroke risk factors (stroke/transient ischaemic attack [TIA] 15.2%; thromboembolism 14.1%; hypertension 84.3%) and high bleeding risk (HAS-BLED score≥3 68.4%) was common. Apixaban-prescribed patients had more frequent history of stroke/TIA (19.7%) and high bleeding risk (72.6%) than other OACs. 12-month persistence rates were: VKA 57.5% (95% confidence interval (CI) 56.0–59.0%), rivaroxaban 56.6% (54.9–58.2%), dabigatran 50.1% (47.2–53.1%), apixaban 62.9% (58.8–67.0%). Over entire follow-up, compared to VKA, non-persistence was similar with apixaban (adjusted hazard ratio 1.08, 95% CI 0.95–1.24) but higher with rivaroxaban (1.21, 1.14–1.29) and dabigatran (1.53, 1.40–1.68). Using post-hoc time-partitioned approach: in first 100 days, non-persistence was higher with apixaban (1.37, 1.17–1.59), rivaroxaban (1.41, 1.30–1.53) and dabigatran (1.91, 1.70–2.14) compared to VKA. Compared to apixaban, rivaroxaban non-persistence was similar (1.03, 0.89–1.20), dabigatran was higher (1.39, 1.17–1.66). After 100 days, apixaban non-persistence was lower than VKA (0.66, 0.52–0.85); rivaroxaban (0.97, 0.87–1.07) and dabigatran (1.10, 0.95–1.28) were similar to VKA. Furthermore, rivaroxaban (1.46, 1.13–1.88) and dabigatran (1.67, 1.26–2.19) non-persistence was higher than apixaban. This study describes real-world observations on OAC use, particularly early apixaban use following approval for NVAF, in Germany. We identified potential differential OAC prescribing and higher persistence with apixaban than other OACs after 100 days’ treatment. Larger studies are needed with longer follow-up to establish long-term patterns.

Adherence to Rivaroxaban, Dabigatran, and Apixaban for Stroke Prevention for Newly Diagnosed and Treatment-Naive Atrial Fibrillation Patients: An Update Using 2013-2014 Data

BACKGROUND

Few studies have assessed adherence to non-vitamin K antagonist oral anticoagulants (NOACs), especially using contemporary data now that multiple NOACs are available.

OBJECTIVE

To compare adherence and treatment patterns among NOACs for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF).

METHODS

Incident and treatment-naive NVAF patients were identified during 2013-2014 from a large claims database in this retrospective cohort study. Patients were included who initiated rivaroxaban, dabigatran, or apixaban within 30 days after diagnosis. Adherence to the index medication and adherence to any oral anticoagulant was assessed using the proportion of days covered (PDC) at 3, 6, and 9 months. The number of switches and gaps in therapy were also evaluated. Analyses were stratified by stroke risk scores, and a logistic regression model was used to control for factors that may predict high adherence.

RESULTS

Dabigatran had lower adherence (PDC = 0.76, 0.64, 0.57) compared with rivaroxaban (PDC = 0.83, 0.73, 0.66; P < 0.001) and apixaban (PDC = 0.82, 0.72, 0.66; P < 0.001) at 3, 6, and 9 months of follow-up and twice the number of switches to either other anticoagulants or antiplatelet therapy. Adherence was higher overall as stroke risk increased, and dabigatran had consistently lower adherence compared with the other NOACs. Multivariable logistic regression predicting PDC ≥ 0.80 showed rivaroxaban users with higher odds of high adherence compared with dabigatran or rivaroxaban across all time periods. Adjusted analyses showed that increasing age and comorbid hypertension and diabetes were associated with higher adherence.

CONCLUSIONS

In this real-world analysis of adherence to NOACs, rivaroxaban and apixaban had favorable unadjusted adherence profiles compared with dabigatran, while rivaroxaban users had higher odds of high adherence (PDC ≥ 0.80) among the NOACs in adjusted analyses. Clinicians and managed care organizations should consider the implications of lower adherence on clinical outcomes and quality assessment.

DISCLOSURES

This project was supported by the National Center for Advancing Translational Sciences, National Institutes of Health, through grant number UL1TR000117. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. The authors have nothing to disclose. Study concept and design were contributed by Brown and Shewale. Brown and Talbert collected the data, and data analysis was performed primarily by Brown, along with Shewale and Talbert. The manuscript was written primarily by Brown, along with Shewale, and revised by all the authors.

Once- versus twice-daily direct oral anticoagulants in non-valvular atrial fibrillation

INTRODUCTION

Direct oral anticoagulants (DOACs) have emerged as alternatives to vitamin K antagonists for the prevention of stroke in patients with non-valvular atrial fibrillation (NVAF). Four DOACs: dabigatran, rivaroxaban, apixaban and edoxaban, are currently available. In the absence of head-to-head clinical comparisons of DOACs, dosing regimen may influence drug choice. Areas covered: Edoxaban and rivaroxaban are administered once daily, dabigatran and apixaban twice daily. The selection of these dosage regimens is largely based on studies for the prevention or treatment of venous thromboembolism or acute coronary syndrome. Edoxaban is the only DOAC in which once and twice-daily regimens were compared in patients with NVAF; bleeding rates were higher in the twice-daily groups. Once-daily versus twice-daily regimens have a number of practical implications. Missing a once-daily dose would have a greater impact on anticoagulation. Some real world and retrospective studies found that a once-daily dosing regimen leads to better adherence and persistence to therapy, an important consideration for maintaining optimum anticoagulation. However, other studies have not found increased adherence among once daily regimens. Expert opinion: Prescription of DOACs should be tailored to the individual patient and dosing regimen is only one of the variables that should be taken into account.

Medium- to long-term persistence with non-vitamin-K oral anticoagulants in patients with atrial fibrillation: Australian experience

OBJECTIVE

Long-term anticoagulant therapy with non-valvular atrial fibrillation (AF) is essential to prevent thromboembolic complications, especially ischemic stroke. This study examines medium-term persistence in AF patients using a non-vitamin-K antagonist oral anticoagulant drug (NOAC).

RESEARCH DESIGN AND METHODS

We assessed national Pharmaceutical Benefit Scheme records December 2013 through September 2016 for initial prescription of a NOAC in a 10% random sample of concessional patients. Key outcome measures were: (a) proportions filling first repeat prescription, (b) proportions persisting with NOAC over 12 and 30 months and (c) proportions switching to another NOAC or warfarin.

RESULTS

A total of 8656 patients with AF initiated a NOAC (3352 apixaban, 1340 dabigatran, 3964 rivaroxaban). Mean age was 77 years, 53% male; 91% collected the first repeat prescription for any NOAC, 70% and 57% collected any NOAC or subsequent warfarin prescription over 12 months and 30 months respectively; 8.9% had switched to warfarin. The proportions switching from apixaban, dabigatran and rivaroxaban to a different NOAC were 14%, 31% and 17% respectively. In a regression model adjusting for age, gender and comorbidity, apixaban-initiated patients over 30 months were 28% more likely to persist with any anticoagulant therapy compared with dabigatran-initiated patients (hazard ratio [95% CI] 1.28 [1.16-1.42]) and 15% more likely to persist compared with rivaroxaban-initiated (1.15 [1.06-1.24]). Rivaroxaban-initiated patients were 12% more likely to persist compared with dabigatran-initiated patients (1.12 [1.02-1.24]).

CONCLUSIONS

Long-term persistence with anticoagulation in patients with AF remains a concern, even with NOACs. Patients initiated to apixaban appear to experience better medium-term persistence compared with rivaroxaban or dabigatran.

Indications for suboptimal low-dose direct oral anticoagulants for non-valvular atrial fibrillation patients

BACKGROUND

Direct oral anticoagulants (DOACs) have been developed for stroke prevention in patients with non-valvular atrial fibrillation (NVAF). We conducted a retrospective cohort study of patients with NVAF who were newly treated with DOACs in a real-world clinical setting.

METHODS

We retrospectively analyzed patients with NVAF newly treated with one of three DOACs-dabigatran, rivaroxaban, or apixaban-between January 1, 2013, and December 31, 2015.

RESULTS

A total of 670 patients with NVAF who were newly prescribed one of the three DOACs were analyzed; 74 patients (10.9%) received dabigatran, 290 (43.3%) received rivaroxaban, and 306 (45.8%) received apixaban. Fifteen patients had thromboembolic events, almost half of which were due to discontinuation of DOACs. Six patients had major bleeding, although almost all were discharged with good neurological prognoses. A total of 129 patients were treated with a suboptimal low-dose DOAC; none experienced a thromboembolic event as long as the DOAC was taken regularly, and none of the patients in any of the three DOAC groups had major bleeding events.

CONCLUSIONS

With good adherence, the clinical course associated with DOACs is comparatively good. In the future, suboptimal low-dose DOAC therapy may serve as an appropriate choice for some patients with a high risk of stroke and bleeding.

Diabetes mellitus and stroke: A clinical update

Cardiovascular disease including stroke is a major complication that tremendously increases the morbidity and mortality in patients with diabetes mellitus (DM). DM poses about four times higher risk for stroke. Cardiometabolic risk factors including obesity, hypertension, and dyslipidaemia often co-exist in patients with DM that add on to stroke risk. Because of the strong association between DM and other stroke risk factors, physicians and diabetologists managing patients should have thorough understanding of these risk factors and management. This review is an evidence-based approach to the epidemiological aspects, pathophysiology, diagnostic work up and management algorithms for patients with diabetes and stroke.