A survey of reasons for continuing warfarin therapy in the era of direct oral anticoagulants in Japanese patients with atrial fibrillation: the SELECT study

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.

Factors associated with non-adherence to the use of coumarin derivatives or direct oral anticoagulants: a systematic review of observational studies

Non-adherence to thromboprophylaxis treatment with oral anticoagulants (OAC) is a public health problem and may be associated with high mortality rates. We sought to synthesize the factors associated with non-adherence to therapy with coumarin derivatives or direct oral anticoagulants. A systematic review was performed at electronic databases Medline, Embase, CINAHL, Lilacs and grey literature (Google Scholar, MedNar, OpenGray, ProQuest Dissertations and Theses and hand search). This study was conducted according to Cochrane's method and PRISMA. The registration on PROSPERO is CRD42020223555. Overall, 1,270 studies were identified and nine studies were selected for this review. In hand search, 77 studies were found, but none included. The associated factors with non-adherence were heterogeneous, and some factors were described as both risk and protection for non-adherence, with few variables showing consistent results among the studies. Variables reported only as risk factors were "male sex"; "hospitalization"; "Charlson score" and "bleeding", while "white race"; CHA₂ DS₂ VASc (score range 2-9)" and "polypharmacy" were reported only as protective factors. Most studies did not present details in the description of concepts and methods to assess non-adherence. In clinical practice, the knowledge on factors associated with non-adherence is helpful to identifying patients at higher risk of complications that would benefit from individualized interventions.

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.

Non-Vitamin K Antagonist Oral Anticoagulants Provide Less Adverse Renal Outcomes Than Warfarin In Non-Valvular Atrial Fibrillation: A Systematic Review and MetaAnalysis

Background

Non‐vitamin K antagonist oral anticoagulants (NOACs) have better pharmacologic properties than warfarin and are recommended in preference to warfarin in most patients with non‐valvular atrial fibrillation. Besides lower bleeding complications, other advantages of NOACs over warfarin particularly renal outcomes remain inconclusive.

Methods and Results

Electronic searches were conducted through Medline, Scopus, Cochrane Library databases, and ClinicalTrial.gov. Randomized controlled trials and observational cohort studies reporting incidence rates and hazard ratio (HR) of renal outcomes (including acute kidney injury, worsening renal function, doubling serum creatinine, and end‐stage renal disease) were selected. The random‐effects model was used to calculate pooled incidence and HR with 95% CI. Eighteen studies were included. A total of 285 201 patients were enrolled, 118 863 patients with warfarin and 166 338 patients with NOACs. The NOACs group yielded lower incidence rates of all renal outcomes when compared with the warfarin group. Patients treated with NOACs showed significantly lower HR of risk of acute kidney injury (HR, 0.70, 95% CI, 0.64–0.76; P<0.001), worsening renal function (HR, 0.83; 95% CI, 0.73–0.95; P=0.006), doubling serum creatinine (HR, 0.58; 95% CI, 0.41–0.82; P=0.002), and end‐stage renal disease (HR, 0.82; 95% CI, 0.78–0.86; P<0.001).

Conclusions

In non‐valvular atrial fibrillation, patients treated with NOACs have a lower risk of both acute kidney injury and end‐stage renal disease when compared with warfarin.

Using the Case-Crossover Design to Assess Short-Term Risks of Bleeding and Arterial Thromboembolism After Switching Between Oral Anticoagulants in a Population-Based Cohort of Patients With Atrial Fibrillation

Using nationwide Danish registries, we conducted a population-based case-crossover study evaluating the association between switching from a vitamin K antagonist (VKA) to a direct oral anticoagulant (DOAC), and vice versa, and 30-day risks of bleeding and arterial thromboembolism in patients with atrial fibrillation (AF). The case-crossover population was identified among oral anticoagulant users during 2011-2018 (n = 123,217) as patients with AF with 1) a case-defining outcome and 2) an anticoagulant switch during the 180 days preceding the outcome. Odds ratios were estimated using conditional logistic regression by comparing the occurrence of switching during the 30-day window immediately preceding the outcome to that in reference windows in the same individual 60-180 days before the outcome. The case-crossover populations for switching from VKA to DOAC and DOAC to VKA comprised 1,382 and 287 case patients, respectively. Switching from VKA to DOAC, but not from DOAC to VKA, was associated with an increased short-term risk of bleeding (odds ratio = 1.42; 95% confidence intervals: 1.13, 1.79, and 1.06; and 0.64, 1.75, respectively) and ischemic stroke (odds ratio = 1.74; 95% confidence intervals: 1.21, 2.51, and 0.92; and 0.46, 1.83, respectively). Our findings suggest that switching from VKA to DOAC is an intermittent risk factor of bleeding and ischemic stroke in patients with AF.

A tutorial on dealing with time-varying eligibility for treatment: Comparing the risk of major bleeding with direct-acting oral anticoagulants vs warfarin

In this tutorial, we focus on the problem of how to define and estimate treatment effects when some patients develop a contraindication and are thus ineligible to receive a treatment of interest during follow-up. We first describe the concept of positivity, which is the requirement that all subjects in an analysis be eligible for all treatments of interest conditional on their baseline covariates, and the extension of this concept in the longitudinal treatment setting. We demonstrate using simulated datasets and regression analysis that under violations of longitudinal positivity, typical associational estimates between treatment over time and the outcome of interest may be misleading depending on the data-generating structure. Finally, we explain how one may define "treatment strategies," such as "treat with medication unless contraindicated," to overcome the problems linked to time-varying eligibility. Finally, we show how contrasts between the expected potential outcomes under these strategies may be consistently estimated with inverse probability weighting methods. We provide R code for all the analyses described.

Implementation of a standardised annual anticoagulation specialist review in primary care

An increasing number of patients are being prescribed direct oral anticoagulants (DOACs), while the patients who remain on warfarin are becoming more complex. There is currently a lack of a standardised anticoagulation review for patients in primary care, resulting in potentially preventable harm events. Our aim was to implement a new service, where a standardised review is carried out by a specialist multidisciplinary secondary care anticoagulation team. Overall, the implementation of a standardised review resulted in better optimisation of anticoagulation management for patients taking either a DOAC or a warfarin. Of the 172 eligible patients prescribed warfarin, 47 (27%) chose to switch a DOAC. The average time in therapeutic range for patients on warfarin before and after the pilot increased from 73.5% to 75%. Of 482 patients taking a DOAC, 35 (7%) were found to be on incorrect dose. In 32 (91%) of 35 patients, the dose was amended after notifying the patient's general practitioner. We also found a significant number of patients inappropriately prescribed concomitant medication such as antiplatelet or non-steroidal anti-inflammatory drugs, potentially putting the patients at an elevated risk of bleeding. While further research is needed; we believe the results of this pilot can be used to help build a case to influence the commissioning of anticoagulation services. Secondary care anticoagulation teams, like our own, may be well-placed to provide or support such services, by working across the primary care and secondary care interface to support our primary care colleagues.

Using non-vitamin K oral anticoagulants in specific patient populations: a study of Korean cases

Non-vitamin K oral anticoagulants (NOACs) are increasingly used as alternatives to conventional therapies and have considerable accumulated real-world clinical data in patients with non-valvular atrial fibrillation (NVAF) or venous thromboembolism (VTE). However, it is not easy to make a complete changeover to NOACs in real-world clinical practice because NOACs still have challenges in specific patient populations (eg, Asian patients, NVAF patients presenting with acute coronary syndrome [ACS], dialysis patients with NVAF, patients with cancer-associated VTE, etc.). Clinical data on the optimal dose of NOACs in Asian patients with NVAF are not sufficient. The intensity of NOAC and antiplatelet treatment and the duration of antiplatelet treatment should be adjusted according to the bleeding and thrombotic risk profiles of the individual NVAF patient presenting with ACS. Increased bleeding risk and unclear efficacy of NOACs in dialysis patients with NVAF should be considered when making decisions on whether to give NOACs for these patients. If dialysis patients with NVAF require anticoagulant for stroke prevention, then apixaban could be considered while awaiting more clinical efficacy and safety data. Additional studies are needed to determine the utility of continuing treatment with reduced-dose NOACs for long-term therapy after VTE. We have enough experiences in using NOACs in cancer patients showing the benefit of antithrombotic treatment counterbalanced the bleeding risk; however, some challenges of cancer-associated VTE management exist due to differences in cancer types or chemotherapy regimens and comorbidities. Different dosing regimens among NOACs may impact on medication adherence; thus, individual patient preference should be considered in choosing a particular NOAC. A significant proportion of patients remain on warfarin because of the high price of NOACs and variability in reimbursement coverage. To compensate clinical-evidence and achieve optimal use of NOACs, we should pay attention to the outcomes of ongoing studies and evaluate more real-world data.

Factors That Affect Time to Switch From Warfarin to a Direct Oral Anticoagulant After Change in the Reimbursement Criteria in Patients With Atrial Fibrillation

BACKGROUND

Anticoagulation therapy is recommended for stroke prevention in high-risk patients with atrial fibrillation (AF). This study aimed to estimate the time to switch from warfarin to a direct oral anticoagulant (DOAC) and identify the factors associated with it.

METHODS

By using claims data, we studied 7111 warfarin-using patients with nonvalvular AF who were aged ≥65 years. The Kaplan-Meier analysis was performed to estimate the time to switch from warfarin to a DOAC, and Cox proportional hazard regression analysis was used to estimate the influencing factors.

RESULTS

Approximately one-third of the patients (2403, 33.8%) switched from warfarin to a DOAC during the study period. Female sex, aged between 75 and 79 years, having a Medical Aid or Patriots and Veterans Insurance, hypertension, and history of prior stroke, and transient ischemic attack or thromboembolism (prior stroke/TIA/TE) were associated with a significantly shorter time to switch. The odds of switching to a DOAC were increased by approximately 1.2-fold in the women and 1.4-fold in the patients with prior stroke/TIA/TE.

CONCLUSIONS

Approximately one-third of the warfarin-using patients switched from warfarin to a DOAC within 6 months after the change in the DOAC reimbursement criteria. In the Cox proportional hazard regression analysis, the factors that affected anticoagulant switching from warfarin to a DOAC were female sex and history of prior stroke/TIA/TE.

Treatment Expectations, Convenience, and Satisfaction with Anticoagulant Treatment: Perceptions of Patients in South-East Queensland, Australia

Background: Warfarin has long been the only oral anticoagulant (OAC) available, but options now include non-vitamin K antagonists. Prescribing an OAC may be influenced by patient factors and preferences influenced by dosing, monitoring, and adverse effects, which may ultimately impact patient satisfaction and convenience. The aim of this study was to explore the perception of OAC treatment by Australian patients in terms of treatment expectations, convenience, and satisfaction. Methods: The Perception of Anticoagulant Treatment Questionnaire was distributed to patients dispensed OAC medication from three pharmacies in South-East Queensland. Responses to questions using a five-point Likert scale were collated and mean results utilised to assess expectations, convenience, and satisfaction, including an analysis across demographic groups. Results: A total of 56 (26.8%) surveys were returned, with the majority of respondent’s male (58.2%). Highest mean scores for treatment expectation were for an OAC that was easy to take (4.85 ± 0.79) and that could be taken care of by the respondents themselves (4.11 ± 1.14). The mean overall score for convenience was 68.90 ± 11.44% and for satisfaction 69.43 ± 16.58%. Significantly higher mean convenience scores were found in females and patients with atrial fibrillation. Conclusions: Patients’ highest expectations were for an OAC that would be easy to take, and overall satisfaction and convenience was around 69%. Factors including demographics can influence perceptions of therapy, and addressing individual preferences for OAC therapy may increase ratings of satisfaction and convenience.

Drug-drug interactions in an era of multiple anticoagulants: a focus on clinically relevant drug interactions

Oral anticoagulants are commonly prescribed but high risk to cause adverse events. Skilled drug interaction management is essential to ensure safe and effective use of these therapies. Clinically relevant interactions with warfarin include drugs that modify cytochrome 2C9, 3A4, or both. Drugs that modify p-glycoprotein may interact with all direct oral anticoagulants, and modifiers of cytochrome 3A4 may interact with rivaroxaban and apixaban. Antiplatelet agents, nonsteroidal anti-inflammatory drugs, and serotonergic agents, such as selective serotonin reuptake inhibitors, can increase risk of bleeding when combined with any oral anticoagulant, and concomitant use should be routinely assessed. New data on anticoagulant drug interactions are available almost daily, and therefore, it is vital that clinicians regularly search interaction databases and the literature for updated management strategies. Skilled drug interaction management will improve outcomes and prevent adverse events in patients taking oral anticoagulants.

Drug-drug interactions in an era of multiple anticoagulants: a focus on clinically relevant drug interactions

Oral anticoagulants are commonly prescribed but high risk to cause adverse events. Skilled drug interaction management is essential to ensure safe and effective use of these therapies. Clinically relevant interactions with warfarin include drugs that modify cytochrome 2C9, 3A4, or both. Drugs that modify p-glycoprotein may interact with all direct oral anticoagulants, and modifiers of cytochrome 3A4 may interact with rivaroxaban and apixaban. Antiplatelet agents, nonsteroidal anti-inflammatory drugs, and serotonergic agents, such as selective serotonin reuptake inhibitors, can increase risk of bleeding when combined with any oral anticoagulant, and concomitant use should be routinely assessed. New data on anticoagulant drug interactions are available almost daily, and therefore, it is vital that clinicians regularly search interaction databases and the literature for updated management strategies. Skilled drug interaction management will improve outcomes and prevent adverse events in patients taking oral anticoagulants.

Antithrombotic therapies for elderly patients: handling problems originating from their comorbidities

Compared with younger people, elderly people have higher risks for both thrombosis and bleeding. Furthermore, comorbidities frequently found in elderly patients complicate the management of antithrombotic therapy. Thus, when treating these patients, physicians often find it difficult to incorporate the principles of evidence-based medicine and must determine the best treatment option for each patient. Recently, in the fields of cerebrovascular and cardiovascular diseases, researchers have been rapidly accumulating new data regarding antithrombotic therapy, particularly in the areas of direct oral anticoagulants (DOACs) and dual antiplatelet therapy (DAPT). However, information related to elderly patients receiving antithrombotic therapy is still relatively limited. There are also more and more publications describing how antithrombotic therapy affects the pathogenesis of non-thrombotic diseases. Similarly, the number of reports concerning adherence to this therapy has been increasing lately. However, no review articles detailing these findings have yet been published. In actual clinical practice, antithrombotic therapy in the elderly is not a treatment strategy targeted to only one organ or disease. Rather, it requires an interdisciplinary approach aimed at maintaining the overall health of the patient. Thus, to assist physicians’ decision-making processes for elderly patients, an overview of recent findings related to the evidence regarding concomitant medications, the secondary benefits of antithrombotic therapy for patients with comorbidities, and evidence regarding medication adherence is provided.

Molecular and Clinical Issues about the Risk of Venous Thromboembolism in Older Patients: A Focus on Parkinson's Disease and Parkinsonism

Venous thromboembolism (VTE) is a common and potentially life-threatening condition which includes both deep-vein thrombosis (DVT) and pulmonary embolism (PE). VTE has a significant clinical and epidemiological impact in the elderly, and its incidence increases to more than 1% per year in older patients, suggesting the presence of specific age-related risk factors in this population. Immobilization seems to predominate as the main cause in patients admitted for medical acute illness in medicine wards, and there is evidence of a high risk in older patients with immobilization resulting from advanced forms of Parkinson’s disease (PD), regardless of the presence of an acute medical condition. In this review, we would to discuss the recent evidence on clinical, molecular and epidemiological features of VTE in older frail subjects focusing on patients with PD and parkinsonism. We also discuss some therapeutic issues about the risk prevention and we suggest a thorough comprehensive geriatric assessment that can represent an optimal strategy to identify and prevent the VTE risk in these patients.