Adherence and outcomes of patients prescribed dabigatran (Pradaxa) in routine clinical practice

Thromboembolic Antiphospholipid Syndrome (APS): Efficacy and Safety of Different Anticoagulants-Results of the APSantiCO Registry

Background: The particular challenge in dealing with patients with thromboembolic antiphospholipid syndrome (APS) is to establish an adequate therapy regime, as patients suffer from an increased risk of relapse despite antithrombotic treatment (ATT). Vitamin K antagonists (VKA) are the standard medication of choice. The current data on the use of direct oral anticoagulants (DOAC) in APS patients remain limited. Methods: The results of the retrospective APSantiCO registry are presented. In 80 patients with APS, the efficacy and safety of different ATT regimens were analyzed. Results: At the time of inclusion, 43.8% of patients were treated with VKA and 36.3% with DOAC. Medication regimes changed several times and 279 treatment phases were further analyzed with a total treatment length of 7529 months. The incidence of recurrent arterial thrombosis was significantly larger in the DOAC group compared with the VKA group (p < 0.001), while the incidence of recurrent venous thrombosis was comparable between both groups, as was the incidence of bleedings. Heavy menstrual bleeding was the most frequently observed bleeding complication. Conclusions: The data suggest that DOAC may be an alternative to VKA for APS patients with venous thromboembolism, while VKA should be used in APS-related arterial thrombosis.

Functional and binding studies of gallic acid showing platelet aggregation inhibitory effect as a thrombin inhibitor

Objective

This study was devoted to identifying natural thrombin inhibitors from traditional Chinese medicine (TCM) and evaluating its biological activity in vitro and binding characteristics.

Methods

A combination strategy containing molecular docking, thrombin inhibition assay, surface plasmon resonance (SPR) and molecular dynamics simulation were applied to verify the study result.

Results

Gallic acid was confirmed as a direct thrombin inhibitor with IC₅₀ of 9.07 μmol/L and showed a significant inhibitory effect on thrombin induced platelet aggregation. SPR-based binding studies demonstrated that gallic acid interacted with thrombin with a K_D value of 8.29 μmol/L. Molecular dynamics and binding free energy analysis revealed that thrombin-gallic acid system attained equilibrium rapidly with very low fluctuations, the calculated binding free energies was −14.61 kcal/mol. Ala230, Glu232, Ser235, Gly258 and Gly260 were the main amino acid residues responsible for thrombin inhibition by gallic acid, providing a mechanistic basis for further optimization.

Conclusion

This study proved that gallic acid is a direct thrombin inhibitor with platelet aggregation inhibitory effect, which could provide a basis for the follow-up research and development for novel thrombin inhibitors.

Incidence and predictors of hospitalization in patients with atrial fibrillation: results from the Chinese atrial fibrillation registry study

Background

Patients with atrial fibrillation (AF) underwent a high risk of hospitalization, which has not been paid much attention to in practice. Therefore, we aimed to assess the incidence, causes and predictors of hospitalization in AF patients.

Methods

From August 2011 to December 2017, a total number of 20,172 AF patients from the Chinese Atrial Fibrillation Registry (China-AF) Study were prospectively selected for this study. We described the incidence, causes of hospitalization by age groups and sex. The Fine-Gray competing risk model was employed to identify predictors of first all-cause and first cause-specific hospitalization.

Results

After a mean follow-up of 37.3 ± 20.4 months, 7,512 (37.2%) AF patients experienced one or more hospitalizations. The overall incidence of all-cause hospitalization was 24.0 per 100 patient-years. Patients aged < 65 years were predominantly hospitalized for AF (42.1% of the total hospitalizations); while patients aged 65–74 and ≥ 75 years were mainly hospitalized for non-cardiovascular diseases (43.6% and 49.3%, respectively). We found patients complicated with heart failure (HF)[hazard ratio (HR) 1.10, 95% confidence interval (CI) 1.02–1.18], established coronary artery disease (CAD) (HR 1.24, 95%CI 1.17–1.33), ischemic stroke/transient ischemic attack (TIA) (HR 1.22, 95%CI 1.15–1.30), diabetes (HR 1.14, 95%CI 1.08–1.20), chronic obstructive pulmonary disease (COPD) (HR 1.28, 95%CI 1.02–1.62), gastrointestinal disorder (HR 1.37, 95%CI 1.21–1.55), and renal dysfunction (HR 1.24, 95%CI 1.09–1.42) had higher risks of hospitalization.

Conclusions

More than one-third of AF patients included in this study were hospitalized at least once during over 3-year follow-up. The main cause for hospitalization among the elderly patients (≥ 65 years) is non-cardiovascular diseases rather than AF. Multidisciplinary management of comorbidities should be advocated to reduce hospitalization in AF patients older than 65 years old.

Clinical Registryhttp://www.chictr.org.cn/showproj.aspx?proj=5831. Unique identifier: ChiCTR-OCH-13003729. The registration date is October 22, 2013.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-01951-5.

Patient Adherence to Novel Oral Anticoagulants (NOACs) for the Treatment of Atrial Fibrillation and Occurrence of Associated Bleeding Events: A Systematic Review and Meta-analysis

BACKGROUND

Real-world evidence from published observational studies of adherence to Novel Oral Anticoagulants (NOACs) medications and associated clinical outcome events in Atrial Fibrillation (AF) patients, was reviewed systematically.

METHODS

Observational studies assessing patient adherence to NOACs conducted on AF patients between September 2010 and June 2016 were identified by systematic searching keywords to locate eligible studies, in accordance with Cochrane guidelines. PubMed, Scopus and Google Scholar databases were searched to identify the studies. Meta-analysis was performed using a random effects model with DerSimonian-Laird weighting to obtain pooled effect sizes.

RESULTS

From 185 potentially relevant citations, 6 studies, comprising 1.6 million AF patients, were included. Among these, successful adherence to NOACs occurred in 75.6%. Adherence levels were higher in patients treated with dabigatran (72.7%) compared with those treated with apixaban (59.9%) or rivaroxaban (59.3%). However, adherence was still suboptimal (relative to an expected 80% adherence rate). Bleeding events in non-adherent patients were found to be 7.5%.

CONCLUSION

Suboptimal adherence to NOACs among AF patients was highlighted as a significant risk factor that may affect clinical outcomes, with a higher percentage of non-adherent patients having bleeding events. There is an urgent need for research on the effects of specific interventions to improve patient adherence to NOACs and to assess the related outcome factors that may be associated with adherence.

[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.

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.

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.

Long-term outcome in patients with non-valvular atrial fibrillation on dabigatran: a prospective cohort study

INTRODUCTION

Most studies on thromboembolic and bleeding risk in patients with non-valvular atrial fibrillation (NVAF) exposed to non-vitamin K oral anticoagulants stem from interrogation of insurance databases. Areas covered: We studied 742 consecutive patients with NVAF who started treatment with dabigatran in three hospitals in Italy. Average follow-up was 1.80 years. Mean age was 76.2 years. CHA₂DS₂VASc score was 0-1 in 37 (5%), 2 in 97 (13%) and ≥ 3 in 604 (82%) patients. NVAF was permanent in 349 (48%). Overall, 76% of patients remained on treatment over the entire follow-up period. Among 180 patients who discontinued permanently, the most frequent reasons were dyspepsia (33.9%), bleeding (17.8%), and renal worsening (12.1%). About 48% and 74% of permanent discontinuations occurred during the first 6 and 12 months of treatment, respectively. Rates of major events (per 100 patient-years) were 0.75 for stroke, 0.31 for myocardial infarction, 1.50 for all-cause death, and 1.80 for major bleedings. The rate of intracranial bleedings was 0.45 and that of major gastrointestinal bleedings was 0.75. Expert opinion: This prospective cohort study confirms the low incidence of stroke, major bleeding and intracranial bleeding, and a 76% persistence with treatment, in patients with NVAF treated with dabigatran over about 2 years.

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.

Adherence with direct oral anticoagulants in nonvalvular atrial fibrillation new users and associated factors: a French nationwide cohort study

Purpose

Direct oral anticoagulants (DOACs) have been promoted in patients with nonvalvular atrial fibrillation (nv‐AF) as a more convenient alternative to vitamin K antagonists. We estimated 1‐year dabigatran and rivaroxaban adherence rates in nv‐AF patients and assessed associations between baseline patient characteristics and nonadherence.

Methods

This cohort study included OAC‐naive nv‐AF patients with no contraindications to OAC, who initiated dabigatran and rivaroxaban, using nationwide data from French national health care databases. One‐year adherence was defined by the proportion of days covered of 80% or more over a fixed 1‐year period after treatment initiation. Associations between nonadherence and baseline patient characteristics were assessed using multivariate logistic regression models.

Results

The population was composed of 11 141 dabigatran (women: 48%; mean age: 74 ± 10.7 y; ≥80 y: 34.9%) and 11 126 rivaroxaban (46.5%; 74 ± 10.9 y; 34.8%) new users. One‐year adherence was 53.3% in dabigatran‐treated and 59.9% in rivaroxaban‐treated patients, consistent with numerous subgroup analyses. A switch to vitamin K antagonist was observed in 14.5% of dabigatran and 11.7% of rivaroxaban patients; 10.2% and 5.9% of patients switched to another DOAC, respectively; and 4.3% of patients died in the 2 cohorts. In patients who did not die or switch during the follow‐up, 1‐year adherence was 69.6% in dabigatran‐treated and 72.3% in rivaroxaban‐treated patients. Having concomitant ischemic heart diseases was associated with an increased risk of nonadherence in the 2 cohorts.

Conclusion

In this real‐life study, 1‐year adherence to DOAC is poor in nv‐AF new users. Despite the introduction of DOAC, adherence to OACs may remain a significant challenge in AF patients.

Use of direct oral anticoagulants in patients with atrial fibrillation in Scotland: Applying a coherent framework to drug utilisation studies

PURPOSE

To report the use of direct oral anticoagulants (DOACs) for stroke prevention in patients with atrial fibrillation in Scotland and advocate the standardisation of drug utilisation research methods.

METHODS

Retrospective cohort study using linked administrative data. Patients included those with a diagnosis of atrial fibrillation (confirmed in hospital) who received a first prescription for a DOAC (dabigatran, rivaroxaban, or apixaban) from September 2011 to June 2014. Drug utilisation measures included discontinuation, persistence, and adherence.

RESULTS

A total of 5398 patients (mean CHA₂ DS₂ -VASc score 2.98 [SD 1.71], 89.7% with ≥5 concomitant medicines) were treated with DOACs for a median of 228 days (interquartile range 105-425). Of 35.6% who discontinued DOAC treatment, 11.0% switched to warfarin, and 48.3% reinitiated DOACs. Persistence after 12 and 18 months was 75.9% and 69.8%, respectively. Differences between individual DOACs were observed: Discontinuation rates ranged from 20.4% (apixaban) to 60.6% (dabigatran) and 12 months persistence from 60.1% (dabigatran) to 85.5% (apixaban). Adherence to treatment with all DOACs was good: Overall DOAC median medication refill adherence was 102.9% (interquartile range 88.9%-115.5%), and 82.3% of patients had a medication refill adherence > 80%.

CONCLUSIONS

In Scotland, adherence to DOAC treatment was good, and switching from DOAC to warfarin was low. However, discontinuation and persistence rates were variable-although treatment interruptions were often temporary. To decrease the inconsistencies in drug utilisation methods and facilitate meaningful study comparison, the use of a coherent framework-using a combination of discontinuation, persistence, and adherence-and the standardisation of measurements is advocated.

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

BACKGROUND

Non-vitamin K antagonist oral anticoagulants (NOACs) are widely used for prevention of stroke secondary to nonvalvular atrial fibrillation (NVAF). Increased use of NOACs is partially a result of simplified regimens compared with warfarin, which has been associated with poor adherence and persistence to therapy. Few studies have assessed adherence to NOACs, especially using contemporary data now that multiple NOACs are available.

OBJECTIVE

To evaluate adherence to NOACs in a cohort of newly diagnosed NVAF patients who are commercially insured.

METHODS

Incident, treatment-naïve NVAF patients were identified in 2013 from a large claims database. Patients were included who initiated rivaroxaban, dabigatran, or apixaban within 30 days after diagnosis. Subjects were required to have 12 months of pre-index information to assess demographic and clinical characteristics (comorbidities, CHA₂ DS₂-VASc, and HAS-BLED scores). Adherence to the index medication and adherence to any oral anticoagulant was assessed using 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 (PDC ≥ 0.80).

RESULTS

A total of 3,455 rivaroxaban, 1,264 dabigatran, and 504 apixaban users were included with no major clinical or demographic differences between groups. At 3, 6, and 9 months of follow-up, dabigatran had lower adherence (PDC = 0.77, 0.67, and 0.62) compared with rivaroxaban (PDC = 0.84, 0.75, and 0.70; P < 0.001) and apixaban (PDC = 0.82, 0.75, and 0.71; P < 0.001), as well as nearly twice the number of switches to either other anticoagulants or antiplatelet therapy. At 9 months, 55.0% of rivaroxaban initiators had PDC ≥ 0.80, which was comparable with 56.8% for apixaban and significantly greater than 46.7% for dabigatran (P < 0.001). Adherence was higher overall as stroke risk increased and showed dabigatran had consistently lower adherence compared with the other NOACs. Overall adherence to any oral anticoagulants, allowing for switches to another NOAC or warfarin, was not dependent on the index medication (9-month PDC = 0.74, 0.71, and 0.74 for rivaroxaban, dabigatran, and apixaban initiators). Adjusted analyses showed that increasing age and comorbid hypertension and diabetes were associated with higher adherence. Compared with rivaroxaban, dabigatran initiators had nearly 30% lower odds of being adherent to their index medication, and no differences were observed between apixaban and rivaroxaban. At 9 months, there were no differences between NOACs for overall adherence to oral anticoagulants.

CONCLUSIONS

In this real-world analysis of adherence to NOACs, rivaroxaban and apixaban had favorable profiles compared with dabigatran, and rivaroxaban appeared to have higher overall adherence among the NOACs. Clinicians and managed care organizations should consider the implications of lower adherence on clinical outcomes as well as quality assessment.

DISCLOSURES

The project described 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. Brown reports receiving a training fellowship from Human and Pfizer. Study concept and design were contributed by Brown and Shewale. Talbert took the lead in data collection, along with Brown, and data interpretation was primarily performed by Brown, along with Shewale. The manuscript was written primarily by Brown, along with Shewale, and revised by all the authors.

Assessment of Patient Adherence to Direct Oral Anticoagulant vs Warfarin Therapy

CONTEXT

Direct oral anticoagulants (DOACs) may be as effective as, and at times safer than, warfarin. Because DOACs do not require regular serum level monitoring, patients' interaction with the health care system may be reduced. To the authors' knowledge, although studies have evaluated warfarin adherence, few studies have evaluated the real-world adherence to DOACs.

OBJECTIVE

To evaluate whether a difference exists between medication adherence of patients taking DOACs vs patients taking warfarin.

METHODS

The electronic medical records of the Anticoagulation Clinic database at Mayo Clinic in Scottsdale, Arizona, were reviewed. Inclusion criteria were adults taking DOACs and a matching cohort taking warfarin between January 1, 2011, and December 30, 2013. The Morisky Medication Adherence Scale-8 item, a validated medication adherence tool, was used to evaluate adherence in both cohorts, and the qualitative covariates were analyzed using ordinal logistic regression.

RESULTS

Of 324 surveys that were sent, 110 patients (34.0%) responded. Most patients took DOACs for atrial fibrillation, and few took DOACs for venous thromboembolism. Overall, 60 of 66 patients (90.9%) in the DOAC group and 42 of 44 patients (95.5%) in the warfarin group reported medium or high adherence. Difference in adherence scores between the 2 groups was not statistically significant (P=.8).

CONCLUSION

Similar adherence was noted between DOACs and warfarin regardless of the frequency of serum level monitoring.

Adherence to a Novel Oral Anticoagulant Among Patients with Atrial Fibrillation

BACKGROUND

Dabigatran is a direct thrombin inhibitor approved by the FDA in October 2010 for the treatment of nonvalvular atrial fibrillation. Little is known regarding patient adherence to this therapy.

OBJECTIVE

To examine adherence and persistence to dabigatran among adults with atrial fibrillation.

METHODS

We used IMS Health's LifeLink Health Plan Claims Database from 2010 to 2012 to identify patients with atrial fibrillation who were new users of dabigatran. We derived adherence and persistence for continuously enrolled patients at 6 months, 9 months, and 12 months of follow-up. We measured adherence using the medication possession ratio (MPR), defined as individuals with MPRs of 0.80 or greater as adherent, and examined persistence by identifying individuals with gaps in drug possession of 60 days or greater.

RESULTS

Of 5,951 adults with atrial fibrillation who were new users of dabigatran, 49% had prevalent atrial fibrillation and at least 6 months of continuous follow-up. Of these, 89% used dabigatran as the only oral anticoagulant, whereas the remainder filled prescriptions for at least 1 other oral anticoagulant during the follow-up period. Among those using dabigatran alone (n = 2,713), the mean MPR was 0.73 (standard error = 0.30), 41% were nonadherent with therapy, and 32% had gaps of 60 days or greater. Among those observed for 9 (or 12) months who used dabigatran alone, rates of nonadherence were 47% (49%), whereas 48% (49%) discontinued therapy during follow-up. Rates of adherence and persistence were similar for patients with incident atrial fibrillation.

CONCLUSIONS

Nonadherence to dabigatran was common among patients with atrial fibrillation. Future studies are needed to understand the reasons for nonadherence.

Effectiveness and safety of dabigatran and warfarin in real-world US patients with non-valvular atrial fibrillation: a retrospective cohort study

Background

The recent availability of dabigatran, a novel oral anticoagulant, provided a new treatment option for stroke prevention in atrial fibrillation beyond warfarin, the main therapy for years. Little is known about their real‐world comparative effectiveness and safety, even less among patient demographic and clinical subgroups.

Methods and Results

Using a cohort of non‐valvular AF patients initiating anticoagulation from October 2010 to December 2012 drawn from a large US database of commercial and Medicare supplement claims, we applied propensity score weights to Cox proportional hazards regression to assess the comparative effectiveness and safety of dabigatran versus warfarin. Analyses were repeated among clinical and demographic subgroups using stratum‐specific propensity scores as an exploratory analysis. Of the 64 935 patients initiating anticoagulation, 32.5% used dabigatran. Compared with warfarin, dabigatran was associated with a lower risk of ischemic stroke or systemic embolism (composite adjusted Hazard Ratio [aHR], 95% CI: 0.86, 95% CI: 0.79 to 0.93), hemorrhagic stroke (aHR: 0.51, 0.40 to 0.65), and acute myocardial infarction (aHR: 0.88, 95% CI: 0.77 to 0.99), and no relation was seen between dabigatran and the composite harm outcome (aHR: 0.94, 95% CI: 0.87 to 1.01). However, dabigatran was associated with a higher risk of gastrointestinal bleeding (aHR: 1.11, 95% CI: 1.02 to 1.22). Estimates of effectiveness and safety appeared to be mostly similar across subgroups.

Conclusions

Dabigatran could be a safe and potentially more effective alternative to warfarin in patients with atrial fibrillation managed in routine practice settings.

Hypersensitivity reactions to modern antiplatelet and anticoagulant drugs

Anticoagulation and antiplatelet drugs are among the most commonly used medical drugs. In addition to the long-established heparins, hirudins, coumarins and antiplatelet drugs such as acetylsalicylic acid, numerous novel and predominantly synthetic pharmacologic agents have come onto the market in recent years. These new agents act at various sites in coagulation and have significantly broadened treatment options. Whilst immunological hypersensitivity reactions are on the whole rare, they have a considerable impact on patient management when they do occur. The present overview discusses the currently known hypersensitivity reactions to anticoagulant and antiplatelet agents, with particular attention to the newer substance classes including P2Y₁₂ inhibitors, glycoprotein IIb/IIIb receptor antagonists, direct factor Xa inhibitors and direct thrombin inhibitors.

Target-specific oral anticoagulants and the hospitalist

As a class, the target-specific oral anticoagulants (TSOACs) are at least as effective as warfarin, often with superior safety for the prevention of stroke in patients with nonvalvular atrial fibrillation (AF) and the treatment of acute venous thromboembolism (VTE) and prevention of recurrent VTE. Currently, dabigatran, the direct thrombin inhibitor, along with rivaroxaban and apixaban, direct factor Xa inhibitors, has been approved in multiple countries for these indications. Edoxaban, which has received approval for the abovementioned indications in Japan, has demonstrated efficacy and safety comparable to or better than warfarin in Phase III clinical trials and is under further regulatory consideration. It is anticipated that the use of TSOACs will increase as practitioners and healthcare systems gain familiarity with these drugs and adopt their use into clinical practice. This review will provide a brief overview of the TSOAC Phase III clinical trials for prevention of stroke and systemic embolic events in patients with AF and the Phase III clinical trials for the prevention of recurrent VTE, discuss current treatment guidelines, address how TSOACs may help meet national safety goals, and provide clinical decision-making guidance regarding the use of TSOACs for hospitalists.

Warfarin versus dabigatran etexilate: an assessment of efficacy and safety in patients with atrial fibrillation

INTRODUCTION

Oral anticoagulation is the mainstay for stroke and thromboembolic event prevention in patients with atrial fibrillation (AF). Given limitations of warfarin therapy, non-vitamin K oral anticoagulants have been developed including direct thrombin inhibitors (i.e., dabigatran etexilate). Dabigatran etexilate has been tested thoroughly in terms of efficacy and safety in clinical trials and studies, involving 'real-world' cohorts. In this review, currently available evidence in patients with non-valvular AF is discussed.

AREAS COVERED

The pharmacology, efficacy and safety, and current aspects of use of dabigatran etexilate in patients with non-valvular AF are reviewed in a comparative manner to warfarin both for chronic anticoagulation and in different clinical settings.

EXPERT OPINION

Dabigatran etexilate appeared to have several pharmacokinetic and pharmacodynamic advantages over warfarin, as well as a favorable efficacy and safety profile being at least noninferior and often superior to warfarin in patients with non-valvular AF. The latter was shown in the clinical trials, meta-analyses and studies with 'real-world' data. Currently ongoing trials will expand the body of evidence on warfarin and will aid decision making in currently controversial areas. Important limitations of dabigatran etexilate include contraindications for its use in patients with prosthetic heart valves and end-stage chronic kidney disease.

Prognosis and treatment of atrial fibrillation patients by European cardiologists: one year follow-up of the EURObservational Research Programme-Atrial Fibrillation General Registry Pilot Phase (EORP-AF Pilot registry)

BACKGROUND

The EURObservational Research Programme-Atrial Fibrillation General Registry Pilot Phase (EORP-AF Pilot) provides systematic collection of contemporary data regarding the management and treatment of 3119 subjects with AF from 9 member European Society of Cardiology (ESC) countries. In this analysis, we report the development of symptoms, use of antithrombotic therapy and rate vs. rhythm strategies, as well as determinants of mortality and/or stroke/transient ischaemic attack (TIA)/peripheral embolism during 1-year follow-up in this contemporary European registry of AF patients.

METHODS

The registry population comprised consecutive in- and out-patients with AF presenting to cardiologists in participating ESC countries. Consecutive patients with AF documented by ECG were enrolled. Follow-up was performed by the local investigator, initially at 1 year, as part of a long-term cohort study.

RESULTS

At the follow-up, patients were frequently asymptomatic (76.8%), but symptoms are nevertheless common among paroxysmal and persistent AF patients, especially palpitations, fatigue, and shortness of breath. Oral anticoagulant (OAC) use remains high, ∼78% overall at follow-up, and of those on vitamin K antagonist (VKA), 84% remained on VKA during the follow-up, while of those on non-VKA oral anticoagulant (NOAC) at baseline, 86% remained on NOAC, and 11.8% had changed to a VKA and 1.1% to antiplatelet therapy. Digitalis was commonly used in paroxysmal AF patients. Of rhythm control interventions, electrical cardioversion was performed in 9.7%, pharmacological cardioversion in 5.1%, and catheter ablation in 4.4%. Despite good adherence to anticoagulation, 1-year mortality was high (5.7%), with most deaths were cardiovascular (70%). Hospital readmissions were common, especially for atrial tachyarrhythmias and heart failure. On multivariate analysis, independent baseline predictors for mortality and/or stroke/TIA/peripheral embolism were age, AF as primary presentation, previous TIA, chronic kidney disease, chronic heart failure, malignancy, and minor bleeding. Independent predictors of mortality were age, chronic kidney disease, AF as primary presentation, prior TIA, chronic obstructive pulmonary disease, malignancy, minor bleeding, and diuretic use. Statin use was predictive of lower mortality.

CONCLUSION

In this 1-year follow-up analysis of the EORP-AF pilot general registry, we provide data on the first contemporary registry focused on management practices among European cardiologists, conducted since the publication of the new ESC guidelines. Overall OAC use remains high, although persistence with therapy may be problematic. Nonetheless, continued OAC use was more common than in prior reports. Despite the high prescription of OAC, 1-year mortality and morbidity remain high in AF patients, particularly from heart failure and hospitalizations.

Dabigatran - a continuing exemplar case history demonstrating the need for comprehensive models to optimize the utilization of new drugs

Background: There are potential conflicts between authorities and companies to fund new premium priced drugs especially where there are effectiveness, safety and/or budget concerns. Dabigatran, a new oral anticoagulant for the prevention of stroke in patients with non-valvular atrial fibrillation (AF), exemplifies this issue. Whilst new effective treatments are needed, there are issues in the elderly with dabigatran due to variable drug concentrations, no known antidote and dependence on renal elimination. Published studies showed dabigatran to be cost-effective but there are budget concerns given the prevalence of AF. These concerns resulted in extensive activities pre- to post-launch to manage its introduction.

Objective: To (i) review authority activities across countries, (ii) use the findings to develop new models to better manage the entry of new drugs, and (iii) review the implications based on post-launch activities.

Methodology: (i) Descriptive review and appraisal of activities regarding dabigatran, (ii) development of guidance for key stakeholder groups through an iterative process, (iii) refining guidance following post launch studies.

Results: Plethora of activities to manage dabigatran including extensive pre-launch activities, risk sharing arrangements, prescribing restrictions and monitoring of prescribing post launch. Reimbursement has been denied in some countries due to concerns with its budget impact and/or excessive bleeding. Development of a new model and future guidance is proposed to better manage the entry of new drugs, centering on three pillars of pre-, peri-, and post-launch activities. Post-launch activities include increasing use of patient registries to monitor the safety and effectiveness of new drugs in clinical practice.

Conclusion: Models for introducing new drugs are essential to optimize their prescribing especially where concerns. Without such models, new drugs may be withdrawn prematurely and/or struggle for funding.