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

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.

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.

Effectiveness and Safety of Extended Oral Anticoagulant Therapy in Patients with Venous Thromboembolism: A Retrospective Cohort Study

Limited real-world evidence exists for effectiveness and safety of extended oral anticoagulation beyond 6 months of initial treatment in prevention of recurrent venous thromboembolism (VTE) and adverse major bleeding events among patients with VTE. Using MarketScan Commercial and Medicare Supplemental databases (2013-2019), we conducted a retrospective cohort study to compare the risk of recurrent VTE and major bleeding events during extended treatment among patients with VTE who completed the 6-month initial treatment and received extended oral anticoagulant treatment with apixaban, warfarin, or no extended treatment. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox proportional hazards modeling with inverse probability treatment weighting. We identified 14,818 patients with extended treatment of apixaban (n = 4,338), warfarin (n = 5,298), or no extended treatment (n = 5,182). Compared with no extended treatment, apixaban use was associated with decreased risk of recurrent VTE (HR: 0.10, 95% CI: 0.04-0.26) without increased risk of major bleeding events (HR: 1.06, 95% CI: 0.52-2.17); warfarin use was associated with decreased risk of recurrent VTE (HR: 0.23, 95% CI: 0.12-0.44) but with increased risk of major bleeding events (HR: 2.64, 95% CI: 1.51-4.59). Compared with warfarin, apixaban use was associated with decreased risk of major bleeding events (HR: 0.42, 95% CI: 0.22-0.80) but no difference in risk of recurrent VTE (HR: 0.46, 95% CI: 0.15-1.36). In a real-world clinical setting, extended anticoagulation with apixaban or warfarin was associated with decreased risk of recurrent VTE compared with no extended treatment, and apixaban had a better safety profile with fewer major bleeding events compared with warfarin among commercially insured patients with VTE.

Adherence is an optimal factor for maximizing the effective and safe use of oral anticoagulants in patients with atrial fibrillation

Few studies assessed the association between major adverse cardiovascular events and adherence to warfarin and direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF). Therefore, we aimed to evaluate the effects of adherence to oral anticoagulants (OACs) in patients with AF using claims data (July 2014–April 2019). Using the initial 3-month medication possession rate (MPR), patients were categorized into adherent (MPR ≥ 0.8) or non-adherent (MPR < 0.8) groups. Propensity score matching of non-adherent group to adherent group was conducted for warfarin (1:1) and DOAC (1:3), respectively. Incidence of ischemic stroke, myocardial infarction (MI), intracranial hemorrhage, and all-cause death was assessed in the matched cohort (67,147 patients). The hazard ratio (HR) for adherence to OAC was estimated using the Cox proportional hazard model with adjusting covariate including age and sex. The risk for ischemic stroke, MI, and all-cause death was lower in the DOAC adherent group than in the DOAC non-adherent group (HR: 0.78; 95% confidence intervals: 0.73–0.84; 0.75, 0.60–0.94; 0.54, 0.51–0.57, respectively). Adherence to OAC was not associated with the risk of intracranial hemorrhage (1.01, 0.85–1.20). Commitment programs to improve adherence in patients with AF could maximize drug effectiveness and safety.

Time Trends and Treatment Pathways in Prescribing Individual Oral Anticoagulants in Patients with Nonvalvular Atrial Fibrillation: An Observational Study of More than Three Million Patients from Europe and the United States

BACKGROUND

Data directly comparing trends in the use of different oral anticoagulants (OACs) among patients with atrial fibrillation (AF) from different countries are limited. We addressed this using a large-scale network cohort study in the United States (US), Belgium, France, Germany, and the United Kingdom (UK).

METHODS

We used nine databases (claims or electronic health records) that had been converted into the Observational Medical Outcomes Partnership Common Data Model with analysis performed using open-source analytical tools. We identified adults with AF and a first OAC prescription, either vitamin K antagonist (VKA) or direct oral anticoagulant (DOAC), from 2010 to 2017. We described time trends in use, continuation, and switching.

RESULTS

In 2010, 87.5%-99.8% of patients started on a VKA. By 2017, the majority started on a DOAC: 87.0% (US), 88.3% (Belgium), 93.1% (France), 88.4% (Germany), and 86.1%-86.7% (UK). In the UK, DOACs became the most common starting OAC in 2015, 2-3 years later than elsewhere. Apixaban was the most common starting OAC by 2017, 50.2%-57.8% (US), 31.4% (Belgium), 45.9% (France), 39.5% (Germany), and 49.8%-50.5% (UK), followed by rivaroxaban, 24.8%-32.5% (US), 25.7% (Belgium), 38.4% (France), 24.9% (Germany), and 30.2%-31.2% (UK). Long-term treatment was less common in the US than in Europe, especially the UK. A minority of patients switched from their index OAC in the short and long term.

CONCLUSIONS

From 2010 to 2017, VKA use had significantly declined and DOAC use had significantly increased in the US and Europe. Apixaban was the most prescribed OAC in 2017, followed by rivaroxaban.

Patients' and clinicians' perceptions of oral anticoagulants in atrial fibrillation: a systematic narrative review and meta-analysis

Background

Atrial fibrillation (AF) increases the risk of developing a stroke by 20%. AF related strokes are associated with greater morbidity. Historically, warfarin was the anticoagulant of choice for stroke prevention in patients with AF but lately patients are being switched or started on direct oral anticoagulants (DOACs). DOACs are promoted as safer alternatives to warfarin and it is expected that they will be associated with fewer challenges both for patients and healthcare professionals. This systematic narrative review aimed to explore perspectives of patients and professionals on medicines optimisation of oral anticoagulation with vitamin K antagonists and DOACs in atrial fibrillation.

Methods

Prospero registration CRD42018091591. Systematic searches undertaken of research studies (qualitative and quantitative), published February 2018 to November 2020 from several databases (Web of Science, Scopus, Medline Via Ovid, CINHAL via Ebsco, and PubMED via NCBI) following PRISMA methodology. Data were organised using Covidence software. Two reviewers independently assessed the quality of the included studies and synthesized the findings (thematic analysis approach).

Results

Thirty-four studies were included. Studies were critically appraised using established critical appraisal tools (Qualsyst) and a risk of bias was assigned. Clinicians considered old age and the associated complexities such as co-morbidities and the increased potential for bleeding as potential barriers to optimising anticoagulation. Whereas patients’ health and medication beliefs influenced adherence. Notably, structured patient support was important in enhancing safety and effective anticoagulation. For both patients and clinicians, confidence and experience of safe anticoagulation was influenced by the presence of co-morbidities,  poor knowledge and understanding of AF and the purpose of anticoagulation.

Conclusion

Age, complex multimorbidity and polypharmacy influence prescribing, with DOACs being perceived to be safer than warfarin. This systematic narrative review suggests that interventions are needed to support patient self-management. There are residual anxieties associated with long term anticoagulation in the context of complexities.

Trial registration

Not applicable.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01590-x.

Defining the duration of the dispensation of oral anticoagulants in administrative healthcare databases

PURPOSE

In clinical practice, warfarin therapy requires frequent dose adjustments. In pharmacy claims, the days supplied value may not reflect the true duration of warfarin dispensation. This may affect the measures of association comparing the safety of direct oral anticoagulants (DOACs) versus warfarin.

METHODS

Using Quebec healthcare administrative databases, we formed a cohort of 55 230 patients newly treated with oral anticoagulants between 2010 and 2016. The duration of dispensations was defined using two approaches: the recorded days supplied value, and the longitudinal coverage approximation (data-driven) that may account for individual variation in drug usage patterns. Propensity scores adjusted Cox proportional hazards regression models were used to estimate the hazard ratio (HR) of major bleeding with dabigatran or rivaroxaban versus warfarin.

RESULTS

Using the days supplied, the mean (and standard deviation) dispensation durations for dabigatran, rivaroxaban, and warfarin were 19 (15), 19 (14), and 13 (12) days, respectively. Using the data-driven approach, the durations were 20 (16), 19 (15), and 15 (16) days, respectively. The choice of the approach had no impact on the HR estimates.

CONCLUSIONS

In our settings, the data-driven approach closely approximated the recorded days supplied value for the standard dose therapies such as dabigatran and rivaroxaban. For warfarin, the data-driven approach captured more variability in the duration of dispensations compared to the days supplied value, which may better reflect the true drug-taking behavior of warfarin. Both approaches may provide valid estimates when comparing the safety of DOACs versus warfarin.

Factors associated with primary nonadherence to newly initiated direct oral anticoagulants in patients with nonvalvular atrial fibrillation

BACKGROUND: Direct oral anticoagulants (DOACs) are widely used for the prevention of stroke in nonvalvular atrial fibrillation (NVAF); however, real-world primary nonadherence (failing to collect the first prescription) has been measured in very few studies. OBJECTIVE: To report primary nonadherence in NVAF patients who are newly prescribed DOACs and identify associated factors. METHODS: This observational retrospective cohort study used a large primary care database in Catalonia. Patients with NVAF who were newly prescribed a DOAC between January 2009 and December 2015 were identified, and primary nonadherence was measured by comparing prescribing records to pharmacy claims data. Multivariable logistic regression was used to determine associated factors. RESULTS: A total of 12,257 patients met the inclusion and exclusion criteria; of these, 1,276 (10.4%) were primary nonadherent. Primary nonadherence was found to be 12.8% for apixaban, 8.6% for dabigatran, and 10.8% for rivaroxaban. Multivariable logistic regression indicated higher odds of primary nonadherence with apixaban and rivaroxaban compared to dabigatran (apixaban: OR = 1.61, 95% CI = 1.39-1.87; rivaroxaban: OR = 1.28, 95% CI = 1.11-1.47). Patients aged at least 80 years showed lower odds of primary nonadherence compared to those aged less than 65 years (OR = 0.78, 95% CI = 0.66-0.93). A diagnosis of chronic kidney disease was associated with primary nonadherence (OR = 1.27, 95% CI = 1.08-1.50). Whereas, diabetes (OR = 0.85, 95% CI = 0.74-0.97), hypertension (OR = 0.79, 95% CI = 0.70-0.91), and stroke/transient ischemic attack (OR = 0.70, 95% C I =0.59-0.82) were inversely associated with primary nonadherence. CONCLUSIONS: Overall, 10.4% of patients prescribed DOACs were primary nonadherent, failing to collect the first prescription. The percentage could have serious implications for patient outcomes and the real-world cost-effectiveness of prescribing DOACs in NVAF. Rates of primary nonadherence and associated factors may provide useful information for the design and evaluation of adherence interventions. DISCLOSURES: No outside funding was received for this study. The data for this study came from the European Medicines Agency PE-PV project (Grant/Award Number EMA/2015/27/PH). The authors have nothing to disclose. A preliminary version of this work was presented at the European Drug Utilisation Research Group (EuroDURG) Conference, Szeged, Hungary, March 5, 2020.

Switching of oral anticoagulants in patients with non-valvular atrial fibrillation: A narrative review

Approval of direct-acting oral anticoagulants (DOACs) for stroke prevention in atrial fibrillation (AF) was an important milestone, providing a wider range of treatment options and creating the possibility for drug switching after initiation. In addition to improved utilisation of oral anticoagulants (OACs) for stroke prevention, reports of switching among OACs are growing in the literature; switching may influence clinical outcomes, healthcare costs and patient satisfaction. This review aimed to summarise the current literature on the pattern of OAC switching in patients with AF, including reasons for switching and clinical consequences following switching. A literature search was conducted in PubMed, Scopus, and Embase on Jun 27, 2020. We included 39 articles published after 2013, following the introduction of apixaban. The review found that switching among OACs was common in clinical practice, significantly varying with the type of OAC. Studies reporting the reason for switching and clinical outcomes were comparatively limited. The decision to switch was often related to safety issues (usually bleeding), poor anticoagulation control and ease-of-use. Patient characteristics, clinical conditions and drug interactions were found to be associated with switching from OACs. Findings regarding bleeding outcomes following switching were inconsistent, possibly confounded by the rationale for switching and the switching protocol. Noting the limited number of studies included and their relatively short follow-up periods, switching did not have a significant impact on the risk of stroke and other thrombotic outcomes. Further prospective studies are needed to understand better potential rationales for switching and the clinical outcomes.

Methodological considerations for investigating oral anticoagulation persistence in atrial fibrillation

AIMS

Reports of long-term oral anticoagulant (OAC) therapy for atrial fibrillation (AF) reveal highly variable, and generally suboptimal estimates of medication persistence. The objective of this review is to summarize current literature and highlight important methodological considerations for interpreting persistence research and designing studies of persistence on OAC treatment.

METHODS AND RESULTS

We summarize differences in study methodology, setting, timing, treatment, and other factors associated with reports of better or worse persistence. For example, prospective compared with retrospective study designs are associated with higher reported persistence. Similarly, patient factors such as permanent AF or high stroke risk, and treatment with non-vitamin K oral antagonists relative to vitamin K antagonists are associated with higher persistence. Persistence has also been reported to be higher in Europe compared with North America and higher when the treating physician is a general practitioner compared with a specialist. We propose a framework for assessing and designing persistence studies. This framework includes aspects of patient selection, reliability and validity of measures, persistence definitions, clinical utility of measurements, follow-up periods, and analytic approaches.

CONCLUSIONS

Differences in study design, patient selection, treatments, and factors such as the countries/regions where studies are conducted or the type of treating physician may help explain the variability in OAC persistence estimates. A framework is proposed to assess persistence studies. This may have utility to compare and interpret published studies as well as for planning of future studies.

[Efficiency of the Decision-Making Module in the Personalized Choice of an Anticoagulant]

Aim        To evaluate the effectiveness of the decision-making module in selecting an oral anticoagulant for patients with atrial fibrillation.Material and methods        638 patients with atrial fibrillation aged 68.2±4.5 years were evaluated. The CHA2DS2-VASc, HAS-BLED, and 2MАСЕ scales, the creatinine clearance calculator, and the Morisky-Green questionnaire were used.Results   311 (48.75 %) patients had paroxysmal atrial fibrillation, 138 (21.6%) had persistent atrial fibrillation, 44 (22.7%) had long-standing persistent atrial fibrillation, and 145 (22.7 %) had permanent atrial fibrillation. Mean CHADS2‑VASc scale score was 4.82; НAS-BLED scale score was 2.9; 2MACE score was 2.28; and compliance score was 3.52. 172 (26.9 %) patients were treated with rivaroxaban; 166 (26 %), with apixaban; 84 (13.2 %), with dabigatran; 210 (32.9 %), with warfarin; and 6 (1 %), with acetylsalicylic acid.Conclusion            The developed decision-making module is based on scientific justification of personalized selection of the oral anticoagulant and updates the knowledge on major issues of prescription.

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.

Insights Into Direct Oral Anticoagulant Therapy Implementation of Stroke Survivors with Atrial Fibrillation in an Ambulatory Setting

OBJECTIVES

To describe how stroke survivors with atrial fibrillation implement direct oral anticoagulant treatment and propose appropriate metrics to describe adherence.

MATERIALS AND METHODS

Stroke patients with atrial fibrillation electronically recorded their self-administered direct oral anticoagulants (apixaban, dabigatran, edoxaban, rivaroxaban) during a 6-month observation phase after hospitalisation for ischemic stroke. Taking and timing adherence, correct dosing days, drug holidays, time of the day and day of the week subsets, dose-to-dose intervals and longest intervals between two consecutive doses were calculated from electronic monitoring data to describe and discuss the implementation phase of adherence.

RESULTS

Data from 41 patients were analysed. Median age was 77 (IQR = 69-84), 63.4% were male and the majority suffered a mild stroke (median NIHSS: 1). Mean taking and timing adherence exceeded 90%. Correct dosing occurred in 86.6% of the days. Seven patients (17.1%) had intake pauses of three or more consecutive days. Patients with twice-daily regimen (70.7%) had higher taking adherence in the morning than in the evening (94.4% versus 89.9%; p = 0.001). No therapy- or anamneses-related characteristic was associated with taking adherence.

CONCLUSIONS

Although adherence to direct oral anticoagulants of stroke patients with atrial fibrillation exceeded 90%, deviant intake patterns such as drug holidays and missed evening doses were common and raise concerns. Appropriate adherence metrics calculated from electronic monitoring data may guide healthcare professionals elucidating patient-tailored adherence-enhancing interventions. ClinicalTrials.gov registration number: NCT03344146.

Updating the Cost Effectiveness of Oral Anticoagulants for Patients with Atrial Fibrillation Based on Varying Stroke and Bleed Risk Profiles

BACKGROUND

Previous investigations into the cost effectiveness of direct oral anticoagulants only considered individual stroke risk but not bleed risk even though bleeding is an important and potentially fatal side effect for anticoagulated patients.

OBJECTIVE

This study aimed to evaluate the cost effectiveness of dabigatran, rivaroxaban, apixaban, and edoxaban vs warfarin in patients with atrial fibrillation with varying stroke/bleed risk profiles over a lifetime horizon.

METHODS

A Markov micro-simulation was adapted to examine the lifetime costs and quality-adjusted survival of five anticoagulants from a US private payer's perspective. The study hypothetical cohort consisted of 10,000 patients with atrial fibrillation with age, CHA₂DS₂-VASc, and HAS-BLED scores similar to a commercially insured patient with atrial fibrillation cohort. Model input parameters including the efficacy and safety of each strategy, utilities, and cost were estimated from public sources, published literature, and analysis conducted in the IBM MarketScan database. Lifetime cost, quality-adjusted life-years, and incremental cost-effectiveness ratios were assessed for each treatment strategy. Subgroup analyses stratified by age, stroke risk score alone, bleed risk score alone and both were performed. Uncertainty was assessed by a deterministic sensitivity analysis and a probabilistic sensitivity analysis.

RESULTS

The base-case analysis suggested dabigatran was the optimal treatment with an incremental cost-effectiveness ratio of $35,055 per quality-adjusted life-year relative to warfarin. Subgroup analyses stratified by age, stroke risk score, and bleed risk score alone were largely consistent with the base-case analysis. Subgroup analyses stratified by both stroke and bleed risk score showed edoxaban was the preferred treatment in patients with a low stroke and a low or medium bleed risk, and patients with a high stroke and low bleed risk. Apixaban was the preferred treatment in patients with a medium stroke and high bleed risk. Results of the deterministic sensitivity analysis indicate the model results were most sensitive to the drug cost and hazard ratio for stroke and bleeding event. Results of the probability sensitivity analysis showed dabigatran is cost effective vs. other treatments in 32.8% and 42.4% of iterations at a willingness to pay of $50,000/quality-adjusted life-year and a willingness to pay of $100,000/quality-adjusted life year, respectively.

CONCLUSIONS

From a US private payer's perspective, dabigatran appears cost effective compared with other anticoagulants. This study indicated risk stratification especially considering both stroke and bleed risk simultaneously is important not only in clinical practice but also in health technology assessment exercises among patients with atrial fibrillation.

Real-World Direct Comparison of the Effectiveness and Safety of Apixaban, Dabigatran, Rivaroxaban, and Warfarin in Medicare Beneficiaries With Atrial Fibrillation

It remains unknown whether the comparative effectiveness of direct oral anticoagulants (DOACs) and warfarin differs between atrial fibrillation patients with and without a history of stroke or transient ischemic attack (TIA). Using 2012 to 2014 Medicare claims data, we identified patients newly diagnosed with AF in 2013 to 2014 who initiated apixaban, dabigatran, rivaroxaban, or warfarin. We categorized patients based on a history of stroke or TIA. We constructed Cox proportional hazard models that included indicator variables for treatment groups, a history of stroke or TIA, and the interaction between them, and controlled for demographics and clinical characteristics. DOACs were generally more effective than warfarin in stroke prevention; however, there were important differences between subgroups defined by a history of ischemic stroke. In particular, the superiority of dabigatran compared with warfarin in ischemic stroke prevention was more pronounced in patients with a history of stroke or TIA (hazard ratio [HR] 0.64; 95% confidence interval [CI] 0.48 to 0.85) than in patients with no history of stroke or TIA (HR 0.94; 95% CI 0.75 to 1.16; p value for interaction = 0.034). There was no difference in the risk of stroke between apixaban, dabigatran, and rivaroxaban in patients with no history of stroke or TIA. However, in patients with a history of stroke or TIA, the risk of stroke was lower with dabigatran (HR 0.64; 95% CI 0.48 to 0.85) and rivaroxaban (HR 0.70; 95% CI 0.56 to 0.87), compared with apixaban (p value for both interactions <0.05). In conclusion, the comparative effectiveness of DOACs differs substantially between patients with and without a history of stroke or TIA; specifically, apixaban is less effective in patients with a history of stroke or TIA.

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.

Real-World Adherence and Persistence to Direct Oral Anticoagulants in Patients With Atrial Fibrillation: A Systematic Review and Meta-Analysis

BACKGROUND

Stroke reduction with direct oral anticoagulants (DOACs) in atrial fibrillation (AF) is dependent on adherence and persistence in the real-world setting. Individual study estimates of DOAC adherence/persistence rates have been discordant. Our aims were to characterize real-world observational evidence for DOAC adherence/persistence and evaluate associated clinical outcomes in patients with AF.

METHODS AND RESULTS

PubMed, EMBASE, and CINAHL were searched from inception to June 2018. Observational studies that reported real-world DOAC adherence/persistence in patients with AF were included. Study quality was assessed using the Newcastle-Ottawa Scale. Meta-analyses for pooled estimates were performed using DerSimonian and Laird random-effects models. Outcomes included DOAC mean proportion of days covered or medication possession ratio, proportion of good adherence (proportion of days covered/medication possession ratio ≥80%), persistence, DOAC versus vitamin K antagonists persistence, and clinical outcomes associated with nonadherence/nonpersistence. Forty-eight observational studies with 594 784 unique patients with AF (59% male; mean age 71 years) were included. The overall pooled mean proportion of days covered/medication possession ratio was 77% (95% CI, 75%-80%), proportion of patients with good adherence was 66% (95% CI, 63%-70%), and proportion persistent was 69% (95% CI, 65%-72%). The pooled proportion of patients with good adherence was 71% (95% CI, 64%-78%) for apixaban, 60% (95% CI, 52%-68%) for dabigatran, and 70% (95% CI, 64%-75%) for rivaroxaban. Similar patterns were found for pooled persistence by agent. The pooled persistence was higher with DOACs than vitamin K antagonists (odds ratio, 1.44 [95% CI, 1.12-.86]). DOAC nonadherence was associated with an increased risk of stroke (hazard ratio, 1.39 [95% CI, 1.06-1.81]).

CONCLUSIONS

Suboptimal adherence and persistence to DOACs was common in patients with AF, with 1 in 3 patients adhering to their DOAC <80% of the time, which was associated with poor clinical outcomes in nonadherent patients. Although it is convenient that DOACs do not require laboratory monitoring, greater effort in monitoring for and interventions to prevent nonadherence may be necessary to optimize stroke prevention. Increased clinician awareness of DOAC nonadherence may help identify at-risk patients.

Application of a Graphical Depiction of Longitudinal Study Designs to Managed Care Pharmacy Research

Managed care pharmacists apply real-world evidence (RWE) to support activities such as pipeline forecasting, clinical policy development, and contracting for pharmaceutical products. Managed care pharmacy researchers strive to produce studies that can be applied in practice. While asking the right research question is necessary, it is not sufficient. As with all studies, consumers of RWE look for internal and external validity, as well as sources of bias, to determine how the study findings can be applied in their work. To date, however, some of the safeguards that exist for clinical trials-such as public registration of study protocols-are lacking for RWE. Several leading professional organizations have initiatives dedicated to improving the credibility and reliability of such research. One component common to these initiatives is enhanced transparency and completeness of methodologic reporting. Graphical representations of study designs can improve the reporting and design of research conducted in health care databases, specifically by enhancing the transparency and clarity of often complex studies. As such, Schneeweiss et al. (2019) proposed a graphical framework for longitudinal study designs in health care databases. Herein, we apply this framework to 2 studies published in the Journal of Managed Care & Specialty Pharmacy that represent common research designs and report how application of the framework revealed deficiencies in reporting. We advocate for adoption of this framework in the effort to increase the usability of RWE studies using health care databases by managed care pharmacy. DISCLOSURES: No funding was provided for this work. Gatwood has received research funding from Merck & Co., AstraZeneca, and GlaxoSmithKline, unrelated to this work. Schneeweiss is a consultant to Aetion, of which he also owns equity. He is the principal investigator of investigator-initiated grants to the Brigham and Women's Hospital from Bayer, Genentech, Boehringer Ingelheim, and Vertex. Wang reports support from investigator-initiated grants from Novartis, Boehringer Ingelheim, and Johnson & Johnson to Brigham and Women's Hospital, unrelated to this work. Happe and Brown have nothing to disclose.

Preliminary Observations on the Antihypertension Action of Dabigatran Etexilate in Patients With Nonvalvular Atrial Fibrillation: A Prospective Multicenter Single-Arm Interventional Study

Background

In Japan, the number of patients with atrial fibrillation continues to grow with the aging of the population. Prevention of cardiogenic cerebral embolism is extremely important in patients with atrial fibrillation. While warfarin has long played a major role for this purpose, a new oral anticoagulant, dabigatran etexilate (dabigatran), has demonstrated superior efficacy and safety in recent years. We conducted a multicenter prospective interventional study to examine whether dabigatran could demonstrate superiority over warfarin in practical clinical situation.

Methods

Among outpatients attending Fukuoka University Chikushi Hospital or clinics registered with the Chikushi Cardiovascular Disease Clinical Research Network (Chikushi-JRN), 143 patients with nonvalvular atrial fibrillation (NVAF) were enrolled in this study and followed up for 12 months after initiation of dabigatran therapy. The primary endpoint was occurrence of cerebral embolism or systemic embolism, while secondary endpoints were: 1) Bleeding events; 2) Changes in the activated partial thromboplastin time (aPTT); 3) Adverse events; and 4) Changes in blood pressure and pulse rate.

Results

During the follow-up period, none of the patients developed cerebral or systemic embolism (the primary endpoint). In addition, there were no bleeding events or other adverse events (the secondary endpoints). aPTT remained stable throughout the 12-month observation period. A significant decrease in systolic blood pressure was observed at 1 month after initiation of dabigatran therapy, and blood pressure was reduced up to 12 months. Blood pressure showed a significant decrease in patients with paroxysmal atrial fibrillation, but not in patients with chronic atrial fibrillation.

Conclusions

Dabigatran showed a stable anticoagulant effect, and its safety was confirmed. Dabigatran also reduced blood pressure, which may help to explain why it causes fewer major bleeding events than warfarin.

Assessing adherence and persistence to non-vitamin K antagonist oral anticoagulants (NOACs) among patients with atrial fibrillation in tertiary-care referral centers in Malaysia

Introduction:

Non-vitamin K antagonist oral anticoagulants (NOACs), such as dabigatran and rivaroxaban, are now available for stroke prevention in patients with atrial fibrillation (AF) and are often clinically preferred over vitamin K antagonists (VKAs), such as warfarin. Data describing adherence and persistence to NOACs in real-life clinical practice in Malaysia are scarce. This study aimed to assess adherence and persistence to NOACs in patients with AF in two tertiary-care referral centers: Hospital Kuala Lumpur (HKL) and Hospital Serdang (HSDG).

Materials and Methods:

This was a retrospective cohort study that included all patients with AF who were treated with NOACs (dabigatran or rivaroxaban) in HKL and HSDG. Data were obtained from medical records and pharmacy databases. Adherence was assessed using proportion of days covered (PDC) over a 1-year duration. High adherence was defined as PDC ≥80%. A gap of >60 days between two consecutive refills was used to define non-persistence.

Result:

There were 281 patients who met the inclusion criteria, with 54.1% (n = 152) male. There were 75.1% (n = 211) patients on dabigatran and others on rivaroxaban. Only 66.9% (n = 188) of patients achieved high adherence with PDC ≥80% and 69.8% (n = 196) were persistence with >60-day gap over 12 months. Adherence and persistence were both influenced by treatment center, whereas polypharmacy only influenced adherence.

Conclusion:

Overall adherence and persistence to NOACs were suboptimal and varied between treatment centers, potentially due to institution-specific administrative and clinical practice differences. Clinical care and outcomes can potentially be optimized by identifying factors affecting adherence and persistence and by implementing interventions to improving them.

[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.

Factors Related to Development of Pancreatic Adenocarcinoma in Patients With Chronic Pancreatitis on Long-term Follow-up: A Database Study

BACKGROUND

Chronic pancreatitis (CP) is a risk factor for pancreatic adenocarcinoma (PA). However, little is known about factors related to development of PA in CP.

OBJECTIVE

To evaluate factors associated with PA in CP.

METHODS

A national insurance database of 120 million US patients was used. Adults with an International Classification of Diseases, Ninth Revision (ICD-9) code for CP (577.1) from January 1, 2009, to December 31, 20014, were identified. Patients' age, sex, and ICD-9 codes for PA, bile duct obstruction, alcohol use, diabetes mellitus before and after diagnosis of CP, obesity, tobacco use, and type of insurance were obtained. Patients with CP without a unique identification number, missing dates for insurance coverage period, and with duration to end of follow-up or development of PA less than 2 years were excluded. The Cox proportional hazards regression model was used for analysis.

RESULTS

The final analysis had 30,555 patients with CP including 219 patients (0.72%) with PA. The Cox proportional hazards regression model showed that in patients with CP age (hazard ratio [HR] = 1.07; 95% Confidence Interval [CI] = 1.03-1.1), male sex (HR = 2.1; 95% CI = 1.25-3.54), tobacco use (HR = 1.88; 95% CI = 1.1-3.23), and having commercial insurance (HR = 4.26; 95% CI = 1.63-11.11) were associated with a subsequent medical claim for PA. Duration of bile duct obstruction (HR = 0.999; 95% CI = 0.998-0.999) and presence of diabetes mellitus before CP (HR = 0.35; 95% CI = 0.19-0.63) were inversely related to subsequent diagnosis of PA.

CONCLUSION

PA was diagnosed in 0.72% of the patients with CP at least 2 years after the diagnosis of CP. Increasing age, male sex, tobacco use, having commercial insurance, absence of diabetes mellitus before CP, and shorter duration of bile duct obstruction were associated with a diagnosis of PA in patients with CP.

Discontinuation of non-Vitamin K antagonist oral anticoagulants in patients with non-valvular atrial fibrillation: a population-based cohort study using primary care data from The Health Improvement Network in the UK

OBJECTIVE

To determine discontinuation rates, patterns of use and predictors of discontinuation of non-vitamin K antagonist oral anticoagulants (NOACs) among patients with non-valvular atrial fibrillation (NVAF) in the first year of therapy.

DESIGN

Population-based cohort study.

SETTING

UK primary care.

POPULATION

11 481 patients with NVAF and a first prescription (index date) for apixaban, dabigatran or rivaroxaban (January 2012 to December 2016) with at least 1 year of follow-up and at least one further NOAC prescription in the year following the index date were identified. 1 year rates and patterns of discontinuation were described.

PRIMARY AND SECONDARY OUTCOME MEASURES

Outcome measures were the percentage of patients who, in the first year from starting NOAC therapy, discontinued with their oral anticoagulant (OAC) therapy (discontinuation was defined as a gap in OAC therapy of >30 days); switched OAC within 30 days; discontinued and reinitiated OAC therapy. Predictors of discontinuation were also evaluated.

RESULTS

1 year discontinuation rates according to the index NOAC were 26.1% for apixaban, 40.0% for dabigatran and 29.6% for rivaroxaban. Reinitiation rates were 18.1% for apixaban, 21.7% for dabigatran and 17.3% for rivaroxaban, and switching rates were 2.8% for apixaban, 8.8% for dabigatran and 4.9% for rivaroxaban. More than 93% of reinitiations were with the index NOAC. Patients starting on dabigatran were more likely to switch OAC therapy than those starting on apixaban; ORs 4.28 (95% CI 3.24 to 5.65) for dabigatran and 1.89 (95% CI 1.49 to 2.39) for rivaroxaban. Severely reduced renal function was a predictor of any discontinuation, OR 1.77 (95% CI 1.28 to 2.44).

CONCLUSION

While the majority of patients with NVAF in the UK initiating NOAC treatment received continuous therapy in the first year of treatment, a substantial proportion of patients experienced gaps in treatment leaving them less protected against thromboembolism during these periods.

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

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

Rivaroxaban in atrial fibrillation cardioversion: an update

Currently, atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with a prevalence of about 2-3% in the general population, representing a powerful risk factor for stroke and systemic thromboembolism and increased mortality and morbidity. Restoration of sinus rhythm is an important treatment option in AF and has a high success rate, but there is the need for an effective anticoagulation strategy to reduce the risk of embolic events. Anticoagulation with vitamin K antagonists is often associated with failure to achieving effective international normalized ratio. In this setting, recent data have led to extended approval for rivaroxaban in clinical practice, because it is effective and safe in patients with AF undergoing cardioversion, avoiding additional health costs and related time loss, while improving patient satisfaction. The present report provides an overview of the main randomized controlled trial and the main real-life studies, documenting the use of rivaroxaban in patients with non-valvular AF who underwent the cardioversion procedure. Considering that novel non-vitamin K antagonist oral anticoagulants in left atrial appendage thrombi resolution is still unknown in the real-world practice, the main findings on the use of rivaroxaban in this setting are also discussed.

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.

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

Introduction

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

Methods

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

Results

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

Conclusion

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

Funding

Pfizer and Bristol-Myers Squibb.

Reducing Stroke Risk in Atrial Fibrillation: Adherence to Guidelines Has Improved, but Patient Persistence with Anticoagulant Therapy Remains Suboptimal

Atrial fibrillation (AF) is a significant risk factor for avoidable stroke. Among high-risk patients with AF, stroke risk can be mitigated using oral anticoagulants (OACs), however reduction is largely contingent on physician prescription and patient persistence with OAC therapy. Over the past decade significant advances have occurred, with revisions to clinical practice guidelines relating to management of stroke risk in AF in several countries, and the introduction of non-vitamin K antagonist OACs (NOACs). This paper summarises the evolving body of research examining guideline-based clinician prescription over the past decade, and patient-level factors associated with OAC persistence. The review shows clinicians' management over the past decade has increasingly reflected guideline recommendations, with an increasing proportion of high-risk patients receiving OACs, driven by an upswing in NOACs. However, a treatment gap remains, as 25–35% of high-risk patients still do not receive OAC treatment, with great variation between countries. Reduction in stroke risk directly relates to level of OAC prescription and therapy persistence. Persistence and adherence to OAC thromboprophylaxis remains an ongoing issue, with 2-year persistence as low as 50%, again with wide variation between countries and practice settings. Multiple patient-level factors contribute to poor persistence, in addition to concerns about bleeding. Considered review of individual patient's factors and circumstances will assist clinicians to implement appropriate strategies to address poor persistence. This review highlights the interplay of both clinician's awareness of guideline recommendations and understanding of individual patient-level factors which impact adherence and persistence, which are required to reduce the incidence of preventable stroke attributable to AF.

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.

Role of the anticoagulant monitoring service in 2018: beyond warfarin

The direct oral anticoagulants (DOACs) have a wide therapeutic index, few drug interaction, no dietary interactions and do not require dose adjustment according to the results of routine coagulation testing. Despite these advantages over warfarin, the DOACs remain high risk medications. There is evidence that non-adherence, off-label dosing and inadequate care transitions during DOAC therapy increase the risk of bleeding and thromboembolic complications. Although DOACs are approved for a growing number of indications, there remain patient populations who are not good candidates. Existing expertise within an Anticoagulation Management Service (AMS) should be leveraged to optimize all anticoagulant therapies including the DOACs. The AMS can facilitate initial drug therapy selection and dose management, reinforce patient education and adherence as well as managing drug interactions and invasive procedures. In the event that a transition to warfarin is warranted, the AMS is already engaged which limits the risk of fragmented patient care and ensures that therapeutic anticoagulation is re-established in a timely manner. The AMS of the future will provide comprehensive management for all patients receiving anticoagulant medications and continue to provide anticoagulation expertise to the healthcare team.

Secondary adherence to non-vitamin-K antagonist oral anticoagulants in patients with atrial fibrillation in Sweden and the Netherlands

OBJECTIVE

There is limited evidence on patients' adherence and the impact of the prescribed dosing regimen in non-vitamin-K oral anticoagulants (NOACs). We aimed to assess secondary adherence to NOACs and to determine the impact of the dosing regimen in patients with atrial fibrillation.

METHODS

Patients using a NOAC between 2009 and 2013 were identified from the nation-wide Swedish Prescribed Drug Register and the Dutch regional IADB.nl database. Patients using a consistent dosage for at least 180 consecutive days were included. Adherence was calculated using the medication possession ratio (MPR) and adjusted for overlapping dates. Adherence was defined as a MPR ≥0.8. Sensitivity analyses were performed using a MPR ≥0.9. Logistic regression was performed to compare secondary adherence and to explore the influence of the dosing regimen.

RESULTS

A total of 5254 Swedish and 430 Dutch NOAC users were included. The mean MPR was 96.0% (SD 7.8%) in Sweden and 95.1% (SD 10.1%) in the Netherlands. Multivariable logistic regression analysis showed that a twice daily regimen had a lower likelihood of being secondary adherent compared to a once daily regimen in Sweden (odds ratio [OR] 0.21 [95% CI 0.12-0.35]).

LIMITATIONS

The influence of selection bias introduced by the inclusion criterion of ≥2 dispensations covering at least 180 days could not be excluded.

CONCLUSIONS

This study demonstrated that secondary adherence was high in this specific setting among patients with at least two initial dispensations of a NOAC covering a minimum of 180 days. The use of NOACs in a once daily regimen showed higher adherence compared to a twice daily regimen.

Strategies for improving dabigatran adherence for stroke prevention in patients with non-valvular atrial fibrillation: education and drug intake reminders (FACILITA study)

Objective To assess the efficacy of a mixed intervention, educational, and reminder calendar of the intake, as a strategy to improve therapeutic adherence with dabigatran in patients with non-valvular atrial fibrillation (NVAF). Methods This was a prospective, longitudinal, multi-center study, carried out in 110 specialized healthcare centers in Spain. Seven hundred and twenty-six patients treated with dabigatran prescribed for stroke prevention were included. A cluster randomization was performed based on two groups: (1) Control Group (CG) as usual clinical practice, and (2) Intervention Group (IG) with a mixed strategy: (a) Healthcare education, and (b) Use of a reminder calendar for taking the anticoagulant medication. Three visits took place: baseline and follow-up at 6 and 12 months. Compliance was measured by using electronic monitors (MEMS). Average adherence percentage (%; Average AP) and daily compliance (%; Daily AP) was calculated. A patient was considered adherent when AP was 80-100%. Results Six hundred and twenty-five patients completed the study (315 in the IG and 310 in the CG). Daily AP was 91.97% at 6 months and 91.05% after 12 months in the IG and 82.26% and 82.63% in the CG. Average adherence was 90.79% and 89.20% in the IG and 64.51% and 63.22% in the CG at 6 and 12 months, respectively. Significant differences were observed in the Daily AP and Average AP, with higher percentages in the IG. In the non-adherents group, the number of concomitant drugs, baseline, and 6 months SBP values, 6 and 12 months DBP values, and weight, total cholesterol, and LDL cholesterol were significantly higher. The number needed to treat (NNT) was 3.84 patients to prevent one non-adherence. Conclusions A mixed intervention, consisting of patient education and a simple calendar reminder of drug intake, is an effective strategy to improve dabigatran therapeutic adherence in patients with NVAF. The percentage of adherence with dabigatran was high.

Anticoagulation with rivaroxaban in a hematology unit: clinical profile, events and discontinuation rates in real-life patients with nonvalvular atrial fibrillation

AIM

To assess the clinical profile and thromboembolic and bleeding events in patients with nonvalvular atrial fibrillation (AF) who were attended in a hematology unit.

METHODS

Retrospective study of AF patients that started treatment with rivaroxaban between February 2012 and June 2016 in a hematology unit from a tertiary hospital in Spain.

RESULTS

Overall, 243 patients (mean age 78.4 ± 10.1 years; 47.5% women, CHA₂DS₂-VASc 3.7 ± 1.5) were included. After a mean follow-up of 16.5 ± 12.7 months, rivaroxaban was discontinued in only 2.4% of patients. During the follow-up, seven (2.0 events/100 patient-years) patients had a thromboembolic event and six patients (1.7 events/100 patient-years) a major bleeding.

CONCLUSION

Rivaroxaban was effective and safe among AF patients treated in a hematology unit, with very low discontinuation rates.

Adherence to rivaroxaban versus apixaban among patients with non-valvular atrial fibrillation: Analysis of overall population and subgroups of prior oral anticoagulant users

BACKGROUND

Medication non-adherence can result in poor health outcomes. Understanding differences in adherence rates to non-vitamin K oral anticoagulants (NOACs) could guide treatment decisions and improve clinical outcomes among patients with non-valvular atrial fibrillation (NVAF).

OBJECTIVE

To compare adherence to rivaroxaban and apixaban among the overall NVAF population and subgroups of prior oral anticoagulant (OAC) users (e.g., multiple comorbidities, non-adherence risk factors).

METHODS

Using healthcare claims from the Truven Health Analytics MarketScan (7/2012-7/2015), adult patients with ≥2 dispensings of rivaroxaban or apixaban ≥ 180 days apart with > 60 days of supply, ≥ 6 months of pre- and post-index eligibility, ≥ 1 atrial fibrillation diagnosis pre- or on the index date, and without valvular involvement were identified. Propensity-score methods adjusting for potential baseline confounders were used to create matched cohorts of rivaroxaban and apixaban patients. Adherence was assessed during the implementation phase using the percentage of patients with proportion of days covered (PDC) ≥0.8 at 6 months. Subgroups of patients with prior OAC use were evaluated; additional subgroups were identified and evaluated by Quan-Charlson Comorbidity index ≥2 and presence of non-adherence risk factors (i.e., mental disorders, stress, isolation, and rheumatoid arthritis).

RESULTS

A total of 13,890 NVAF subjects were included in each of the 2 matched cohorts. All baseline characteristics were balanced between cohorts. At 6 months, significantly more rivaroxaban users were adherent to treatment compared to apixaban users (81.8% vs. 78.0%; absolute difference of 3.8%; p<.001). Rivaroxaban users had significantly higher adherence rates in all subgroups examined.

CONCLUSION

Rivaroxaban users had consistently higher adherence rates than apixaban users overall and among all NVAF subgroups examined.