Persistence of oral anticoagulant treatment for atrial fibrillation in the Netherlands: A surveillance study

Effect of Previous INR Control during VKA Therapy on Subsequent DOAC Adherence and Persistence, in Patients Switched from VKA to DOAC

INTRODUCTION

 Current guideline suggests a switch from vitamin K antagonist (VKA) to direct oral anticoagulant (DOAC) in patients with low time in therapeutic range (TTR < 70%). Poor international normalized ratio (INR) control may be the result of poor compliance, and might therefore be associated with subsequent DOAC intake. Therefore, this study evaluates the effect of previous TTR and other measures of INR control on DOAC nonadherence and nonpersistence, in patients who switched from VKA to DOAC.

METHODS

 A total of 437 patients who switched from VKA to DOAC between 2012 and 2019 were included using data from Certe Thrombosis Service, IADB.nl pharmacy community database University Groningen, and Statistics Netherlands. DOAC prescriptions were used to determine nonadherence and nonpersistence. INR control (i.e., TTR, time under therapeutic range [TUR], and INR variability) was assessed during the last 180 days of VKA use. Multivariable regression models were applied to determine the association between INR control and DOAC nonpersistence/nonadherence.

RESULTS

 On VKA, 67.7% of the patients had a TTR below 70%. DOAC nonpersistence was 39.8% (95% confidence interval [CI]: 33.4-45.5%) during a median follow-up of 34.4 months (interquartile range: 19.1-49.2). Approximately 80% of persistent patients were DOAC-adherent. Low TTR was not associated with DOAC nonpersistence (hazard ratio: 1.14, 95% CI: 0.69-1.87) and DOAC nonadherence (odds ratio: 1.38, 95% CI: 0.67-2.84), nor were TUR and INR variability.

CONCLUSION

 Previous INR control during VKA therapy is not associated with subsequent DOAC nonadherence and nonpersistence. This study suggests that INR control on VKA cannot, and therefore should not, be used for predicting DOAC adherence or persistence.

Non‑persistence to Oral Anticoagulation Therapy in Elderly Patients with Non‑valvular Atrial Fibrillation

PURPOSE

To investigate the reasons for elderly atrial fibrillation (AF) patients not continuing their oral anticoagulation (OAC) treatment and the factors that influence this behavior.

METHODS

Elderly AF patients (aged≥75 years) hospitalized from December 2019 to May 2022 were consecutively enrolled. Clinical, demographic, and concomitant medication data were collected. The endpoint was defined as OAC discontinuation for more than 30 days or a switch to an alternative therapy. Predictors of OAC non-persistence were investigated using a multivariable Cox regression model.

RESULTS

This study included 560 participants (51.1% men, mean age 80.9±0.2 years). During a median follow-up of 20 months, medication persistence was observed in 322 patients (57.5%). Non-persistence was found to be significantly higher with warfarin than with NOAC (48.8% vs 33.6%, p = 0.006). In the multivariate analysis, OAC non-persistence was independently predicted by a history of permanent pacemaker implantation, the use of antiplatelet drugs, employee Medicare, living with children, college degree or above, and persistent AF (HR = 1.580, 1.586, 0.604, 0.668, 0.028, 0.769, p < 0.05, respectively). Treatment discontinuation within 3 months of discharge was observed in a large number of patients (81.8%). Medication discontinuation due to bleeding was more frequently observed in patients who continued for longer than 3 months (p < 0.001), while discontinuation due to patient preference was more frequent in those with shorter durations (≤3 months) (p = 0.049). Patient preference was the second leading cause of non-persistence in patients, regardless of whether they were taking warfarin or NOAC.

CONCLUSION

OAC non-persistence remains high among elderly AF patients during long-term follow-up, with a significant proportion discontinuing shortly after discharge. This pattern of non-persistence is heavily influenced by demographic factors and patient preference. Further interventions should be developed based on the reasons and risk factors to improve persistence and initiated early in the treatment process.

Management of Patients Treated with Direct Oral Anticoagulants in Clinical Practice and Challenging Scenarios

It is well established that direct oral anticoagulants (DOACs) are the cornerstone of anticoagulant strategy in atrial fibrillation (AF) and venous thromboembolism (VTE) and should be preferred over vitamin K antagonists (VKAs) since they are superior or non-inferior to VKAs in reducing thromboembolic risk and are associated with a lower risk of intracranial hemorrhage (IH). In addition, many factors, such as fewer pharmacokinetic interactions and less need for monitoring, contribute to the favor of this therapeutic strategy. Although DOACs represent a more suitable option, several issues should be considered in clinical practice, including drug-drug interactions (DDIs), switching to other antithrombotic therapies, preprocedural and postprocedural periods, and the use in patients with chronic renal and liver failure and in those with cancer. Furthermore, adherence to DOACs appears to remain suboptimal. This narrative review aims to provide a practical guide for DOAC prescription and address challenging scenarios.

Oral anticoagulant switching in patients with atrial fibrillation: a scoping review

INTRODUCTION

Oral anticoagulants (OACs) prevent stroke in patients with atrial fibrillation (AF). Several factors may cause OAC switching.

OBJECTIVES

To examine the phenomenon of OAC switching in patients with AF, including all available evidence; frequency and patterns of switch, clinical outcomes, adherence, patient-reported outcomes, reasons for switch, factors associated with switch and evidence gaps.

DESIGN

Scoping review.

DATA SOURCES

MEDLINE, Embase and Web of Science, up to January 2022.

RESULTS

Of the 116 included studies, 2/3 examined vitamin K antagonist (VKA) to direct-acting OAC (DOAC) switching. Overall, OAC switching was common and the definition of an OAC switch varied across. Switching from VKA to dabigatran was the most prevalent switch type, but VKA to apixaban has increased in recent years. Patients on DOAC switched more to warfarin than to other DOACs. OAC doses involved in the switches were hardly reported and patients were often censored after the first switch. Switching back to a previously taken OAC (frequently warfarin) occurred in 5%-21% of switchers.The risk of ischaemic stroke and gastrointestinal bleeding in VKA to DOAC switchers compared with non-switchers was conflicting, while there was no difference in the risk of other types of bleeding. The risk of ischaemic stroke in switchers from DOAC versus non-switchers was conflicting. Studies evaluating adherence found no significant changes in adherence after switching from VKA to DOAC, however, an increase in satisfaction with therapy were reported. Reasons for OAC switch, and factors associated with OAC switch were mostly risk factors for stroke and bleeding. Clinical outcomes, adherence and patient-reported outcomes were sparse for switches from DOACs.

CONCLUSIONS

OAC switching is common in patients with AF and patients often switch back to an OAC they have previously been on. There are aspects of OAC switching that have received little study, especially in switches from DOACs.

Social and psychological risk factors for decreased adherence among patients with atrial fibrillation

Adherence has a direct impact on reducing the effectiveness of atrial fibrillation therapy and increasing the risk of thromboembolic events. Among the factors involved in the decrease of adherence, the social and psychological characteristics of patients remain insufficiently studied. At the same time, the available publications allow us to conclude that there are markers of the risk of reduced adherence in patients with atrial fibrillation, which include age, cognitive impairment, psychoemotional disorders (including depression and anxiety) and specific behavioral patterns.

Comparing atrial fibrillation guidelines: Focus on stroke prevention, bleeding risk assessment and oral anticoagulant recommendations

Clinical practice in atrial fibrillation (AF) patient management is constantly evolving. In the past 3 years, various new AF guidelines or focused updates have been published, given this rapidly evolving field. In 2019, the American College of Cardiology/American Heart Association published a focused update of the 2014 guidelines. In 2020, both the European Society of Cardiology and the Canadian Cardiovascular Society released their new guidelines. Finally, the most recent guidelines were those published in 2021 by the Asian Pacific Heart Rhythm Society, which updates their 2017 version and the 2021 National Institute for Health and Care Excellence (NICE) guidelines. In the present narrative review, we compare these guidelines, emphasizing similarities and differences in the following mainstay elements of patient care: thromboembolic risk assessment, oral anticoagulants (OACs) prescription, bleeding risk evaluation, and integrated patient management. A formal evaluation of baseline thromboembolic and bleeding risks and their reassessment during follow-up is evenly recommended, although some differences in using risk stratification scores. OACs prescription is highly encouraged where appropriate, and prescription algorithms are broadly similar. The importance of an integrated and multidisciplinary approach to patient care is emerging, aiming to address several different aspects of a multifaceted disease.

Association of income and educational levels with adherence to direct oral anticoagulant therapy in patients with incident atrial fibrillation: A Finnish nationwide cohort study

Low socioeconomic status has been associated with poor outcomes in patients with atrial fibrillation (AF). However, little is known about socioeconomic disparities in adherence to stroke prevention with direct oral anticoagulants (DOACs). We assessed the hypothesis that AF patients with higher income or educational levels have better adherence to DOACs in terms of treatment implementation and persistence. The used nationwide registry‐based FinACAF cohort covers all patients with incident AF starting DOACs in Finland during 2011–2018. The implementation analyses included 74 222 (mean age 72.7 ± 10.5 years, 50.8% female) patients, and persistence analyses included 67 503 (mean age 75.3 ± 8.9 years, 53.6% female) patients with indication for permanent anticoagulation (CHA₂DS₂‐VASc score >1 in men and >2 in women). Patients were divided into income quartiles and into three categories based on their educational attainment. Therapy implementation was measured using the medication possession ratio (MPR), and patients with MPR ≥0.90 were defined adherent. Persistence was measured as the incidence of therapy discontinuation, defined as the first 135‐day period without DOAC purchases after drug initiation. Patients with higher income or education were consistently more likely adherent to DOACs in the implementation phase (comparing the highest income or educational category to the lowest: adjusted odds ratios 1.18 (1.12–1.25) and 1.21 (1.15–1.27), respectively). No association with income or educational levels was observed on the incidence of therapy discontinuation. In conclusion, we observed that income and educational levels both have independent positive association on the implementation of DOAC therapy but no association on therapy persistence in patients with AF.

The Immediate Effect of COVID-19 Vaccination on Anticoagulation Control in Patients Using Vitamin K Antagonists

Background  In January 2021, the Dutch vaccination program against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was started. Clinical studies have shown that systemic reactions occur in up to 50% of vaccine recipients. Therefore, COVID-19 vaccination could affect anticoagulation control, potentially leading to an increased risk of thrombotic events and bleeding complications.

Aims  This article investigates whether the BNT162b2 vaccine affects anticoagulation control in outpatients using vitamin K antagonists (VKAs).

Methods  A case-crossover study was performed in a cohort of outpatient VKA users from four Dutch anticoagulation clinics who received a BNT162b2 vaccine. International normalized ratio (INR) results and VKA dosages before the first vaccination, the reference period, were compared with those after the first and second vaccination.

Results  A total of 3,148 outpatient VKA users were included, with a mean age (standard deviation) of 86.7 (8.7) years, of whom 43.8% were male, 67.0% used acenocoumarol, and 33.0% phenprocoumon. We observed a decrease of 8.9% of INRs within range in the standard intensity group (target INR 2.0–3.0). There was both an increased risk of supratherapeutic (odds ratio [OR] = 1.34 [95% confidence interval [CI] 1.08–1.67]) and subtherapeutic levels (OR = 1.40 [95% CI 1.08–1.83]) after first vaccination. In the high-intensity group (target INR 2.5–3.5), the risk of a supratherapeutic INR was 2.3 times higher after first vaccination (OR = 2.29 [95% CI 1.22–4.28]) and 3.3 times higher after second vaccination (OR = 3.25 [95% CI 1.06–9.97]).

Conclusion  BNT162b2 was associated with an immediate negative effect on anticoagulation control in patients treated with VKAs, so it is advisable to monitor the INR shortly after vaccination, even in stable patients.

Adherence to Direct Oral Anticoagulants in Patients With Non-Valvular Atrial Fibrillation: A Cross-National Comparison in Six European Countries (2008-2015)

Aims: To describe and compare the adherence to different direct oral anticoagulants (DOACs) in eight European databases representing six countries. Methods: Longitudinal drug utilization study of new users (≥18 years) of DOACs (dabigatran, rivaroxaban, apixaban) with a diagnosis of non-valvular atrial fibrillation (2008-2015). Adherence was examined by estimating persistence, switching, and discontinuation rates at 12 months. Primary non-adherence was estimated in BIFAP and SIDIAP databases. Results: The highest persistence rate was seen for apixaban in the CPRD database (81%) and the lowest for dabigatran in the Mondriaan database (22%). The switching rate for all DOACs ranged from 2.4 to 13.1% (Mondriaan and EGB databases, respectively). Dabigatran had the highest switching rate from 5.0 to 20.0% (Mondriaan and EGB databases, respectively). The discontinuation rate for all DOACs ranged from 16.0 to 63.9% (CPRD and Bavarian CD databases, respectively). Dabigatran had the highest rate of discontinuers, except in the Bavarian CD and AOK NORDWEST databases, ranging from 23.2 to 64.6% (CPRD and Mondriaan databases, respectively). Combined primary non-adherence for examined DOACs was 11.1% in BIFAP and 14.0% in SIDIAP. There were differences in population coverage and in the type of drug data source among the databases. Conclusion: Despite the differences in the characteristics of the databases and in demographic and baseline characteristics of the included population that could explain some of the observed discrepancies, we can observe a similar pattern throughout the databases. Apixaban was the DOAC with the highest persistence. Dabigatran had the highest proportion of discontinuers and switchers at 12 months in most databases (EMA/2015/27/PH).

Effects of a transitional care programme on medication adherence in an older cardiac population: A randomized clinical trial

AIMS

Medication non-adherence post-discharge is common among patients, especially those suffering from chronic medical conditions, and contributes to hospital admissions and mortality. This study aimed to evaluate the effect of the Cardiac Care Bridge (CCB) intervention on medication adherence post-discharge.

METHODS

We performed a secondary analysis of the CCB randomized single-blind trial, a study in patients ≥70 years, at high risk of functional loss and admitted to cardiology departments in six hospitals. In this multi-component intervention study, community nurses performed medication reconciliation and observed medication-related problems (MRPs) during post-discharge home visits, and pharmacists provided recommendations to resolve MRPs. Adherence to high-risk medications was measured using the proportion of days covered (PDC), using pharmacy refill data. Furthermore, MRPs were assessed in the intervention group.

RESULTS

For 198 (64.7%) of 306 CCB patients, data were available on adherence (mean age: 82 years; 58.9% of patients used a multidose drug dispensing [MDD] system). The mean PDC before admission was 92.3% in the intervention group (n = 99) and 88.5% in the control group (n = 99), decreasing to 85.2% and 84.1% post-discharge, respectively (unadjusted difference: -2.6% (95% CI -9.8 to 4.6, P = .473); adjusted difference -3.3 (95% CI -10.3 to 3.7, P = .353)). Post-hoc analysis indicated that a modest beneficial intervention effect may be restricted to MDD non-users (P_interaction  = .085). In total, 77.0% of the patients had at least one MRP post-discharge.

CONCLUSIONS

Our findings indicate that a multi-component intervention, including several components targeting medication adherence in older cardiac patients discharged from hospital back home, did not benefit their medication adherence levels. A modest positive effect on adherence may potentially exist in those patients not using an MDD system. This finding needs replication.

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.

Risk of stroke and other thromboembolic complications after interruption of DOAC therapy compared with warfarin therapy in patients with atrial fibrillation: a retrospective cohort analysis

Direct oral anticoagulants (DOACs) have become the treatment of choice in thromboembolism prophylaxis for non-valvular atrial fibrillation, surpassing warfarin. While interruption of DOAC therapy for various reasons is a common eventuality, the body of data from real-world clinical practice on the implications of such interruptions in different clinical settings is still limited. We assessed complication rates from DOAC (apixaban, rivaroxaban, dabigatran) interruption compared with warfarin in hospitalized patients. We performed a retrospective cohort analysis of electronic records of patients hospitalized in Rabin Medical Center between 2010 and 2017. Incidents of anticoagulation interruptions for various reasons (including unintended interruptions) were collected. DOAC-treated patients were excluded if they reported non-compliance, and warfarin-treated patients were excluded if their international normalized ratio measurement on admission was subtherapeutic. Outcomes included ischemic stroke, systemic thromboembolism, myocardial infarction, and all-cause mortality within 90 days of anticoagulation interruption. The median CHA2DS2-VASc score was 5.0 (IQR 4.0-6.0) in both treatment groups. The associated risk of stroke, thromboembolic complications, myocardial infarction, and all-cause mortality after interruption of anticoagulation was not significantly different between the 2 treatment groups. Selective comparison of patients who were well balanced on warfarin before treatment interruption to DOAC-treated patients did not significantly influence the outcomes. This study did not find a significant difference in the complication rate after interruption of DOAC therapy compared with interruption of warfarin therapy in hospitalized patients with a high risk of thromboembolism.

Anticoagulation trends in adults aged 65 years and over with atrial fibrillation: a cohort study

Objective

To describe patterns of anticoagulation prescription and persistence for those aged ≥65 years with atrial fibrillation (AF).

Methods

Descriptive cohort study using electronic general practice records of patients in England, who attended an influenza vaccination aged ≥65 years and were diagnosed with AF between 2008 and 2018. Patients were stratified by 10-year age group and year of diagnosis. Proportion anticoagulated, type of anticoagulation (direct oral anticoagulant (DOAC) or warfarin) initiated at diagnosis and persistence with anticoagulation over time are reported.

Results

42 290 patients (49% female), aged 65–74 (n=11 722), 75–84 (n=19 055) and 85+ (n=11 513) years at AF diagnosis are included. Prescription of anticoagulation at diagnosis increased over the time period from 55% to 86% in people aged 65–74 years, from 54% to 86% in people aged 75–84 years and from 27% to 75% in people aged 85 years and over. By 2018, 92% of patients with newly diagnosed AF were started on a DOAC. Survivor function for 5-year persistence in patients prescribed DOAC was 0.80 (95% CI 0.77 to 0.82) and for warfarin 0.71 (95% CI 0.70 to 0.72). Survivor function for any anticoagulation at 5 years was 0.79 (95% CI 0.78 to 0.81), 0.73 (95% CI 0.72 to 0.75) and 0.58 (95% CI 0.59 to 0.64) for people aged 65–74, 75–84 and 85+ years, respectively.

Conclusions

Rates of anticoagulation in AF in those aged ≥65 years have increased from 2008 to 2018, over which time period there has been a shift from initiating anticoagulation with warfarin to DOAC. Persistence with anticoagulation is higher in people on DOACs than on warfarin and in people aged <85 years.

Predictors, time course, and outcomes of persistence patterns in oral anticoagulation for non-valvular atrial fibrillation: a Dutch Nationwide Cohort Study

Aims 

Persistence with direct oral anticoagulants (DOACs) has become a concern in non-valvular atrial fibrillation (NVAF) patients, but whether this affects prognosis is rarely studied. We investigated the persistence with oral anticoagulants (OACs) and its association with prognosis among a nationwide cohort of NVAF patients.

Methods and results 

DOAC-naive NVAF patients who started to use DOACs for ischaemic stroke prevention between 2013 and 2018 were included using Dutch national statistics. Persistence with OACs was determined based on the presence of a 100-day gap between the last prescription and the end of study period. In 93 048 patients, 75.7% had a baseline CHA₂DS₂-VASc score of ≥2. The cumulative incidence of persistence with OACs was 88.1% [95% confidence interval (CI) 87.9–88.3%], 82.6% (95% CI 82.3–82.9%), 77.7% (95% CI 77.3–78.1%), and 72.0% (95% CI 71.5–72.5%) at 1, 2, 3, and 4 years after receiving DOACs, respectively. Baseline characteristics associated with better persistence with OACs included female sex, age range 65–74 years, permanent atrial fibrillation, previous exposure to vitamin K antagonists, stroke history (including transient ischaemic attack), and a CHA₂DS₂-VASc score ≥2. Non-persistence with OACs was associated with an increased risk of the composite outcome of ischaemic stroke and ischaemic stroke-related death [adjusted hazard ratio (aHR) 1.79, 95% CI 1.49–2.15] and ischaemic stroke (aHR 1.58, 95% CI 1.29–1.93) compared with being persistent with OACs.

Conclusion 

At least a quarter of NVAF patients were non-persistent with OACs within 4 years, which was associated with poor efficacy of ischaemic stroke prevention. The identified baseline characteristics may help identify patients at risk of non-persistence.

Stroke risk factors and outcomes among hospitalized women with atrial fibrillation

Observational cohort analyses suggest that women with atrial fibrillation (AF) endure a greater burden of stroke. We conducted an analysis of an observational cohort study completed at our tertiary care medical center to assess sex-related differences in cardiovascular risk factors, prescription of antithrombotic therapy, and 90-day outcomes. We analyzed 5000 hospitalized patients with AF: 1888 women and 3112 men. Clinical characteristics of AF, risk of stroke and bleeding, prescription of antithrombotic therapy, and 90-day clinical outcomes, including stroke and all-cause mortality, were compared. We observed a 50% higher relative frequency of stroke in hospitalized women with AF compared with men. While the frequencies of prescription of antithrombotic therapy at discharge were similar, anticoagulation was omitted in 40% of women with AF. The 90-day frequencies of major adverse events and mortality were increased in hospitalized women with AF not prescribed antithrombotic therapy at discharge. Prescription of anticoagulation in women with AF at hospital discharge was associated with a 60% and 40% relative reduction in the odds of mortality and major adverse events at 90 days. In conclusion, women hospitalized with AF have a higher risk of stroke at 90 days compared with men. Anticoagulation at hospital discharge was omitted in 40% of women with AF, but when prescribed, was associated with a reduction in mortality and major adverse events at 90 days, respectively. We analyzed 5000 hospitalized patients with atrial fibrillation (AF) (1888 women and 3112 men) in an observational cohort study completed at our tertiary care medical center to assess sex-related differences in cardiovascular risk factors, prescription of antithrombotic therapy, and 90-day outcomes. We observed a 50% higher relative frequency of stroke in hospitalized women with AF compared with men. The 90-day frequencies of major adverse events and mortality were increased in hospitalized women with AF not prescribed antithrombotic therapy at discharge. Prescription of anticoagulation in women with AF at hospital discharge was associated with a 60% and 40% relative reduction in the odds of mortality and major adverse events at 90 days.

Adherence to direct oral anticoagulant treatment for atrial fibrillation in the Netherlands: A surveillance study

BACKGROUND

Adherence to direct oral anticoagulants (DOACs) in patients with atrial fibrillation in every day practice may be less than in clinical trials.

AIMS

To assess adherence to DOACs in atrial fibrillation patients in every day practice and identify predictors for non-adherence.

METHODS

Individual linked dispensing data of atrial fibrillation patients who used DOACs were obtained from the Foundation for Pharmaceutical Statistics covering the Netherlands between 2012 and 2016. One year adherence to DOAC was calculated for initial DOAC as proportion of days covered (PDC) ≥80% and the association between clinical variables and adherence was assessed using logistic regression. In addition, we measured non-persistence, that is, patients who completely stopped their initial DOAC within 1 year follow-up.

RESULTS

A total of 4797 apixaban-, 20 454 rivaroxaban- and 18 477 dabigatran users were included. The mean age was 69 years (n = 43 910), which was similar for the DOAC types. The overall proportion of patients with PDC ≥80% was 76%, which was highest for apixaban- (87%), followed by dabigatran- (80%) and rivaroxaban (69%) users. Multivariable analyses revealed that age ≤60 years, no concomitant drug use were predictors for non-adherence. Of atrial fibrillation patients who continued treatment, 97% had a PDC ≥80%, compared with only 56% for those who discontinued their DOAC treatment within 1 year.

CONCLUSIONS

Non-adherence to DOACs was associated with age ≤60 years and no concomitant drugs use. Non-adherence was higher in patients who later discontinued DOAC treatment. Results of our study support research into interventions to improve adherence.

Design and rationale of DUTCH-AF: a prospective nationwide registry programme and observational study on long-term oral antithrombotic treatment in patients with atrial fibrillation

INTRODUCTION

Anticoagulation therapy is pivotal in the management of stroke prevention in atrial fibrillation (AF). Prospective registries, containing longitudinal data are lacking with detailed information on anticoagulant therapy, treatment adherence and AF-related adverse events in practice-based patient cohorts, in particular for non-vitamin K oral anticoagulants (NOAC). With the creation of DUTCH-AF, a nationwide longitudinal AF registry, we aim to provide clinical data and answer questions on the (anticoagulant) management over time and of the clinical course of patients with newly diagnosed AF in routine clinical care. Within DUTCH-AF, our current aim is to assess the effect of non-adherence and non-persistence of anticoagulation therapy on clinical adverse events (eg, bleeding and stroke), to determine predictors for such inadequate anticoagulant treatment, and to validate and refine bleeding prediction models. With DUTCH-AF, we provide the basis for a continuing nationwide AF registry, which will facilitate subsequent research, including future registry-based clinical trials.

METHODS AND ANALYSIS

The DUTCH-AF registry is a nationwide, prospective registry of patients with newly diagnosed 'non-valvular' AF. Patients will be enrolled from primary, secondary and tertiary care practices across the Netherlands. A target of 6000 patients for this initial cohort will be followed for at least 2 years. Data on thromboembolic and bleeding events, changes in antithrombotic therapy and hospital admissions will be registered. Pharmacy-dispensing data will be obtained to calculate parameters of adherence and persistence to anticoagulant treatment, which will be linked to AF-related outcomes such as ischaemic stroke and major bleeding. In a subset of patients, anticoagulation adherence and beliefs about drugs will be assessed by questionnaire.

ETHICS AND DISSEMINATION

This study protocol was approved as exempt for formal review according to Dutch law by the Medical Ethics Committee of the Leiden University Medical Centre, Leiden, the Netherlands. Results will be disseminated by publications in peer-reviewed journals and presentations at scientific congresses.

TRIAL REGISTRATION NUMBER

Trial NL7467, NTR7706 (https://www.trialregister.nl/trial/7464).

Self-reported therapy adherence and predictors for nonadherence in patients who switched from vitamin K antagonists to direct oral anticoagulants

BACKGROUND

Many patients who used vitamin K antagonists (VKAs) for long-term prevention of thromboembolism are now actively switched to a direct oral anticoagulant (DOAC). Strict adherence to a DOAC is crucial for its success. However, therapy adherence and clinical factors that predict nonadherence are currently not well studied among patients who switched from a VKA to a DOAC.

METHODS

A questionnaire was developed and sent to 2920 former patients of 3 anticoagulation clinics in the Netherlands, who switched from a VKA to a DOAC between January 2016 and December 2017. Questions concerned demographics, treatment persistence, adherence, and the occurrence of bleeding or thromboembolic events on DOACs. To identify predictors for nonadherence, logistic regression models were used to estimate crude and age/sex-adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

A total of 1399 questionnaires (response rate 48%) were used for analysis. DOAC treatment persistence (94%) and adherence (86%) rates were high. Several predictors of nonadherence were identified, including young age (OR, 5.9; 95% CI, 3.6-9.8 for <60 years compared to >75 years), low consultation frequency with a specialist (OR, 1.6; 95% CI, 1.1-2.2), a history of minor bleeding on DOACs (OR, 1.9; 95% CI, 1.3-2.8), and a twice-daily dosing regimen (OR, 1.9; 95% CI, 1.3-2.6).

CONCLUSIONS

Self-reported treatment persistence and adherence were high in our study population, and several predictors of nonadherence were identified. Factors that can be influenced (low consult frequency with medical specialist, daily dosing regimen) may be used to improve therapy adherence.