Pre-admission warfarin use in patients with acute ischemic stroke and atrial fibrillation: The appropriate use and barriers to oral anticoagulant therapy

doi:10.1016/j.thromres.2006.12.019

Thrombosis Research

Volume 120, Issue 5, 2007, Pages 663-669

https://doi.org/10.1016/j.thromres.2006.12.019 Get rights and content

Abstract

Introduction

Warfarin reduces the risk of stroke in patients with atrial fibrillation. Despite strong guideline recommendations, studies continue to demonstrate the under-use of warfarin in clinical practice.

Purpose

To determine the prevalence and predictors of warfarin use in patients presenting with atrial fibrillation and acute ischemic stroke who do not have a documented contraindication to anticoagulants.

Methods

We conducted a retrospective chart review of all patients admitted to the Hamilton General Hospital with a primary diagnosis of ischemic stroke and a coded diagnosis of atrial fibrillation between 1999 and 2004. Using a standardized data abstraction form, the following variables were recorded: baseline demographics, past medical history including risk factors for stroke and major bleeding and known predictors of warfarin under-use. In cases where warfarin was not prescribed, charts were also reviewed for documented contraindications to warfarin use. The following were considered valid contraindications to warfarin: patient refusal, non-compliance with INR monitoring, bleeding diathesis, history of major bleeding or significant alcohol consumption.

Results

In total, 196 patients with ischemic stroke and atrial fibrillation were identified. Of these patients, 106 were considered to be appropriate candidates for anticoagulation after excluding patients with no known diagnosis of atrial fibrillation prior to admission (N = 59), a valid contraindication to warfarin use (N = 18), a CHADS2 score < 1 (N = 6) or a competing diagnosis for warfarin use (N = 7). Of the patients deemed to be suitable candidates for warfarin, 57 (54%) were receiving warfarin therapy on admission. On multivariable analyses, increasing age (OR 0.7; 95% CI 0.5–0.9) was associated with a reduced odds of warfarin use while a history of stroke or TIA (OR 2.6; 95% CI 1.1–6.5) and a history of congestive heart failure (OR 3.2; 95% CI 1.1–9.0) were associated with an increased odds of warfarin use in patients without a contraindication to warfarin. While 75% of patients < 75 years old were anticoagulated, only 33% of those > 85 years were prescribed warfarin on admission to hospital.

Conclusions

early half of all patients presenting with atrial fibrillation and acute ischemic stroke who were suitable candidates for anticoagulation were not prescribed warfarin. In patients not prescribed warfarin, very few had a documented contraindication. Advanced age appears to be the strongest predictor of warfarin non-use.

Section snippets

Background

Atrial fibrillation (Afib) is the most common sustained cardiac arrhythmia detected in 2% of the general population [1]. The prevalence of atrial fibrillation increases with age from 0.5% in people aged 50–59 years to 8.8% of those aged 80–89 [2]. Afib is associated with a five-fold increase in the risk of ischemic stroke. Fortunately, oral anticoagulant therapy (e.g. warfarin) significantly reduces the relative risk of stroke by 62%, whereas aspirin affords a 22% relative risk reduction [3].

Methods

This project was reviewed and approved by the research ethics committee at Hamilton Health Sciences.

Results

A total of 291 patients admitted with a coded diagnosis of stroke and Afib were identified. Following chart review, 95 patients were excluded because patients presented with a primary intracranial hemorrhage (N = 48), patients had a past history of a stroke but no new CVA on current the admission (N = 18), a diagnosis of ischemic stroke could not be confirmed (N = 5), stroke occurred following admission (N = 11), Afib could not be confirmed (N = 10) and patients presented with an unusual cause of

Discussion

In our study, only 54% of patients considered to be appropriate candidates for anticoagulation who presented with acute ischemic stroke were prescribed warfarin prior to admission. A previous study, the Clinical Quality Improvement Network (CQIN) study, investigated the use of thromboembolic prophylaxis in patients, with and without stroke, on admission and discharge to 12 Canadian hospitals between 1993 and 1994. In that study, only 16% of patients presenting to hospital with a diagnosis of

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Stroke prevention in atrial fibrillation: Closing the gap
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The Guideline-Policy Gap in Direct-Acting Oral Anticoagulants Usage in Atrial Fibrillation: Evidence, Practice, and Public Policy Considerations
2018, Canadian Journal of Cardiology
Atrial fibrillation has a high disease burden—both in prevalence and associated consequences. Despite anticoagulation being an effective treatment in atrial fibrillation, stroke prevention is slow to reflect evidence-based practice. Real-world data reveal a substantial portion of patients who would benefit from anticoagulation, yet do not receive it adequately or at all. A large part of this suboptimal treatment is due to the underutilization of direct oral anticoagulants (DOACs). In response to abundant evidence published over a short timeframe, international guidelines have adopted DOAC usage ahead of policy and fund holders. This paper reviews the evidence and values that influence published guidelines, patient-physician decision making, and policy framework on DOAC usage. An important factor is the access gap between patients who qualify for DOAC according to evidence-based guidelines and the subset of this cohort who are eligible for DOAC based on government funded policy. We analyse the Canadian health system in detail—including drug approval and funding process. Health care systems in other countries are explored, with emphasis on similar universal health care systems that may help overcome barriers common to Canada. We will discuss strategies to: (1) improve awareness of the risk and preventability of stroke; (2) enable physicians to provide evidence-based DOAC usage; (3) empower patients to improve adherence and persistence; (4) collect real-life data that encourages patient self-monitoring, physician outcomes auditing, and building evidence that is useful for policy makers; and (5) use postmarketing data in negotiating shared risk management between pharmaceuticals and government to improve access to DOACs.
La fibrillation auriculaire (FA) impose un fardeau très lourd, sur le plan tant de sa prévalence que de ses conséquences. Malgré l’efficacité de l’anticoagulation contre la FA, la prévention des accidents vasculaires cérébraux (AVC) tarde à suivre la pratique fondée sur les données probantes. Les données obtenues en situation réelle montrent qu’une fraction appréciable de patients chez lesquels l’anticoagulation serait bénéfique ne reçoivent pas ce traitement, ou le reçoivent selon des modalités inappropriées. Ce traitement sous-optimal s’explique en grande partie par la sous-utilisation des anticoagulants oraux directs (AOD). En réponse à l’abondance des données probantes publiées en peu de temps, les lignes directrices internationales ont devancé les décideurs et les bailleurs de fonds en préconisant l’utilisation des AOD. Cet article présente une recension des données probantes et des valeurs qui influencent les lignes directrices publiées, la prise de décision patient-médecin et le cadre politique relativement à l’utilisation des AOD. L’écart en matière d’accès au traitement entre les patients admissibles aux AOD selon les lignes directrices fondées sur des données probantes et le sous-ensemble de cette cohorte qui y est admissible en fonction des politiques gouvernementales constitue un facteur important. Nous analysons en profondeur le système de santé canadien, y compris le processus d’homologation et de financement des médicaments. Nous explorons aussi les systèmes de santé d’autres pays, en nous arrêtant plus particulièrement aux systèmes de soins de santé universels semblables au nôtre qui pourraient aider à surmonter les obstacles rencontrés au Canada. Nous discutons des stratégies permettant d’atteindre les objectifs suivants : 1) améliorer la sensibilisation au risque et au caractère évitable de l'AVC 2) permettre aux médecins d’offrir l’utilisation des AOD selon les pratiques fondées sur des données probantes; 3) habiliter les patients à améliorer leur observance et leur persévérance; 4) recueillir des données en situation réelle afin d’encourage l’autosurveillance du patient et la vérification des résultats par le médecin et de constituer un corpus de données probantes susceptibles d’être utiles aux décideurs; 5) utiliser les données post-commercialisation dans la négociation de la gestion partagée des risques entre les sociétés pharmaceutiques et le gouvernement afin d’améliorer l’accès aux AOD.
Atrial Fibrillation as an Ischemic Stroke Clinical and Economic Burden Modifier: A 15-Year Nationwide Study
2017, Value in Health
Citation Excerpt :
On top of increasing the risk of death [4], AF is associated with an increased risk of stroke [5], a leading cause of morbidity and mortality worldwide [6]. AF has been documented in a range of 15% to 38% of the patients suffering from an ischemic stroke (IS) [7–21]. Several studies demonstrated that AF-related IS cases had more severe functional deficits and increased complication rates, leading not only to higher mortality, but also longer hospital stays and increased nursing care [7,8,12,16,22–24].
Atrial fibrillation (AF) is a major risk factor for ischemic stroke (IS). Patients with AF may undergo preventive therapy. Although the AF impact in the clinical burden of IS has been studied, information is lacking in Southern Europe and there are no studies about the impact in potential years of life lost. Moreover, no nationwide or long-term study analyzed the economic burden of IS stratified by AF.
To study the impact of AF in the clinical and economic burden of IS.
We conducted a retrospective study using nationwide administrative data for all public hospitalizations in mainland Portugal from 2000 to 2014. We considered IS hospitalizations stratified by the presence of AF as secondary diagnosis.
Of the total 275,173 IS hospitalizations, 22.6% reported AF. The total number of IS hospitalizations increased from 14,836 in 2000 to 19,561 in 2014 (32% increase), with an increase of 138% in the AF group (from 2,411 to 5,727). In-hospital mortality decreased from 13.6% to 11.5% and was consistently higher in the AF group (17.3% vs. 11.1%). Mean charges were also higher in the AF group (€2297 vs. €2191). Age-adjusted potential years of life lost rate was higher in the group without AF (39.6 vs. 7.5).
AF-associated IS hospitalizations more than doubled in the studied 15-year period. Also, AF was responsible for higher in-hospital mortality and hospitalization charges. These facts highlight the need for early detection of AF and preventive treatment to limit IS occurrence, its associated burden, and poorer health outcomes.
Oral Anticoagulant Use in Atrial Fibrillation-Associated Ischemic Stroke: A Retrospective, Multicenter Survey in Northwestern China
2017, Journal of Stroke and Cerebrovascular Diseases
Anticoagulation therapy has been recommended by major guidelines to reduce the risk of recurrent stroke in patients with atrial fibrillation-associated ischemic stroke (AFAIS). However, in real-world clinical practice, oral anticoagulants with either vitamin K antagonists or nonvitamin K antagonists are often underused for these patients. Here, we sought to investigate the current status of oral anticoagulant use in patients with AFAIS in northwestern China.
We reviewed medical records of consecutive patients with AFAIS discharged from 14 hospitals in northwestern China between January 2012 and May 2015.
A total of 1014 cases were included in this study. The mean age of the patients was 70.3 ± 10.8 years. Fifty-four percent were female. Among all participants, only 20.0% received anticoagulants (19.4% warfarin and .6% nonvitamin K antagonist oral anticoagulants), whereas 57.5% took antiplatelet drugs and 22.5% received neither anticoagulant nor antiplatelet treatment. Anticoagulant use decreased with increasing age and CHA2DS2-VASc scores. The proportions of anticoagulant use at discharge in patients younger than 65 years, 65-74 years, and 75 years or older were 28.5%, 20.7%, and 13.9%, respectively. Nonvalvular atrial fibrillation patients with CHA2DS2-VASc scores of 2, 3, 4, 5, 6, and 7 had anticoagulant use rates at discharge of 19.2%, 24.8%, 20.3%, 13.7%, 8.1%, and 8.0%, respectively.
In northwestern China, oral anticoagulants are substantially underutilized in patients with AFAIS, especially in patients at higher risk of stroke, suggesting a large treatment gap in the secondary prevention management in patients with AFAIS.
Paroxysmal atrial fibrillation and the hazards of under-treatment
2016, International Journal of Cardiology
Citation Excerpt :
In addition, the patient- and physician-specific factors that lead to discontinuation of OAC therapy and the communication strategies that underlie and influence these decisions are poorly understood. Despite the increasing risk of ischemic stroke, multiple studies have demonstrated the paradox of decreased OAC use with older age and higher CHADS2 scores [17,21,24,34,39,40]. We have previously shown that bleeding risk and risk of warfarin discontinuation increase with CHADS2 score [39].
Oral anticoagulants are highly efficacious for the prevention of stroke in atrial fibrillation, and are the preferred treatment by current guidelines. The purpose of our study was to assess the utilization of antithrombotic drugs in atrial fibrillation patients at the time of ischemic stroke and the factors associated with their use.
We enrolled 759 consecutive patients admitted with ischemic stroke at Boston Medical Center, Geisinger Health System, and the University of Alabama. To be eligible, patients had to have electrocardiographically-confirmed atrial fibrillation at the time of admission or within 6 months of the index stroke. All stroke events and electrocardiograms were validated by study physicians. Patients with newly diagnosed atrial fibrillation were not eligible.
The mean age was 78 years, 43% were male, 19% black, and the mean CHADS₂ score is 3.0. Atrial fibrillation was paroxysmal in 31%. At presentation, 181 (24%) patients were taking warfarin only, 96 (13%) both warfarin and aspirin, 294 (39%) aspirin alone, and 189 (25%) no antithrombotic therapy. The mean international normalized ratio was 1.6. Among patients with paroxysmal atrial fibrillation, one in five was taking warfarin. Although increasing stroke risk was associated with a greater likelihood of warfarin use, only 39% of highest risk CHADS₂ 3–6 were taking warfarin at the time of stroke.
Among high-risk individuals with atrial fibrillation, only 37% were taking warfarin at the time of stroke. Paroxysmal atrial fibrillation was associated with the highest risk of not receiving warfarin.
Oral anticoagulant treatment in geriatric patients with nonvalvular atrial fibrillation in the era of direct oral anticoagulant agents
2014, European Journal of Internal Medicine

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REGULAR ARTICLEPre-admission warfarin use in patients with acute ischemic stroke and atrial fibrillation: The appropriate use and barriers to oral anticoagulant therapy

Abstract

Introduction

Purpose

Methods

Results

Conclusions

Section snippets

Background

Methods

Results

Discussion

Chest

Chest

Chest

Am J Med

Epidemiologic features of chronic atrial fibrillation: the Framingham Study

N Engl J Med

Atrial fibrillation as an independent risk factor for stroke

Stroke

Antithrombic therapy to prevent stroke in patients with atrial fibrillation: a meta-analysis

Ann Intern Med

Thromboembolic prophylaxis in 3575 hospitalized patients with atrial fibrillation

Why do patients with atrial fibrillation not receive warfarin?

Arch Intern Med

Why isn't warfarin prescibed to patients with nonrheumatic atrial fibrillation?

J Gen Intern Med

The relative importance of barriers to the prescription of warfarin for nonvalvular atrial fibrillation

Can J Cardiol

REGULAR ARTICLE
Pre-admission warfarin use in patients with acute ischemic stroke and atrial fibrillation: The appropriate use and barriers to oral anticoagulant therapy