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

Clinical Characteristics, Outcomes, and Risk Factors for Adverse Events in Elderly and Non-Elderly Japanese Patients With Non-Valvular Atrial Fibrillation ― Competing Risk Analysis From the Hokuriku-Plus AF Registry ―

Background: Few studies in Japan have reported on follow-up data regarding the clinical course and risk factors for adverse outcomes in elderly patients with non-valvular atrial fibrillation (NVAF), vs. younger patients, when considering the competing risk of death.

Methods and Results: We prospectively studied 1,328 patients with NVAF (965 men; mean [±SD] age 72.4±9.7 years) from the Hokuriku-Plus AF Registry with a median follow-up of 5.0 years (interquartile range 3.5–5.3 years) and evaluated the incidence of thromboembolism or major bleeding in elderly (age ≥75 years; n=595) and non-elderly (age <75 years; n=733) patients. Analysis using the Gray method showed no significant difference in the incidence of thromboembolism; however, the incidence of major bleeding was significantly higher in the elderly than non-elderly group. The Fine-Gray model, after adjustment for age and sex in the elderly group, showed that age (hazard ratio [HR] 1.08; 95% confidence interval [CI] 1.02–1.13; P=0.004) and warfarin use (HR 1.87; 95% CI 1.12–3.14; P=0.02) were significantly associated with major bleeding. In the elderly group, those using warfarin had a higher incidence of thromboembolism and major bleeding than those using direct oral anticoagulants (DOACs).

Conclusions: The efficacy and safety of DOACs were remarkable in elderly compared with non-elderly patients with NVAF considering the competing risk of death. DOACs may be a favorable choice in elderly patients with NVAF.

Novel bleeding prediction model in atrial fibrillation patients on new oral anticoagulants

OBJECTIVE

Clinical models such as the HAS-BLED (standing for Hypertension, Abnormal liver/renal function, Stroke history, Bleeding history or predisposition, Labile INR, Elderly, Drug/alcohol usage) were developed to predict risk of major bleeding on vitamin K antagonists/antiplatelet therapy. We aimed to develop a model that will improve the ability to predict major bleeding events in patients with non-valvular atrial fibrillation (AF) treated with new oral anticoagulants (NOACs).

METHODS

Clalit Health Services is the largest of four integrated healthcare organisations in Israel, which insures 4.7 million patients (53% of the population). We identified in Clalit Health Services all patients with AF, new users of an NOAC (2013-2017), and followed them until first occurrence of a major bleeding event, death, switch to another oral anticoagulant, 30 days after discontinuation of NOAC or end of follow-up (31 December 2019). Importance of the candidate model variables was estimated by inclusion frequencies across forward selection algorithm applied to 50 bootstrap samples. Then, backward selection algorithm using the modified Bayesian Information Criterion for competing risks was applied to select predictors for the final model.

RESULTS

47 623 patients with AF prescribed NOAC were studied. 28 055 patients with AF, initiators of apixaban (mean age 78.7, SD 9.0), were included in the first phase and had 662 major bleeding events. Nine variables were selected for inclusion in a final points-based risk-scoring system: male sex, anaemia, thrombocytopaenia (<99×10³/µL), concurrent antiplatelet therapy, hypertension, prior major bleeding, risk factors for a fall, low cholesterol level and low estimated glomerular filtration rate, with apparent area-under-curve (AUC) of 0.6546. Applicability of the model was then shown for 14 118 and 5450 patients with AF, initiators of dabigatran and rivaroxaban, where the score achieved c indices of 0.62 and 0.61, respectively.

CONCLUSIONS

We present a novel and simple risk score for prediction of major bleeding in patients with non-valvular AF treated with NOACs. Validation in additional cohorts is warranted.

Examination of anticoagulation prescription among elderly patients with atrial fibrillation after in-hospital fall

Mechanical fall is common among elders and has been associated with a lack of anticoagulant therapy among patients with atrial fibrillation (AF). However, anticoagulant therapy is recommended despite frequent fall due to an increased risk of a thromboembolic event. Using data from a large health system, we investigated the predictors of anticoagulation prescription on discharge in AF elderly patients after an in-hospital fall. In this retrospective analysis, we examined patients aged 60 years and older discharged from 2013 to 2018 with a diagnosis of AF and a secondary diagnosis of in-hospital fall. The primary outcome was the prescription of anticoagulation at discharge. We obtained patients' demographical (race, sex, and health insurance status) and clinical (management by a resident team, receipt of a head CT or a cardiology consultation, ambulation status and discharge location) data. We further categorized the type of anticoagulation prescribed as warfarin or novel oral anticoagulants (NOACs). We ran chi-square and Fischer's exact tests on all data and multivariable logistic regressions on those of patients with pre-existing AF to identify the predictors of anticoagulation prescription on discharge. In total, 67% of 235 patients were discharged on anticoagulation. Of patients admitted on anticoagulation, 91% were prescribed anticoagulation on discharge (p < 0.001), while only 40% of patients with new-onset AF were discharged on anticoagulation (p < 0.001). Patients over the age of 90, compared to those aged 60-89, with existing AF had lower odds (OR = 0.34 [95% CI 0.12-0.98]) of being prescribed anticoagulation on discharge. Among patients with preexisting AF, being admitted on anticoagulation increased the odds (OR = 39.8 [15.2-104.0]) of anticoagulation prescription on discharge. Asian patients with prior AF were less likely (OR = 0.12 [0.026-0.060]) to receive anticoagulation on discharge. Of patients with new AF, 81% were prescribed a NOAC as opposed to warfarin (p < 0.05). These results suggest that provider's decisions on anticoagulation initiation seem to be guided more by their concerns over bleeding complications than by the patient's risk for stroke. However, anchoring bias strongly influences anticoagulation prescription. It may benefit AF patients already on anticoagulation, but it may prevent anticoagulation prescription in patients with new AF and Asian patients.

Physician decision making in anticoagulating atrial fibrillation: a prospective survey of a physician notification system for atrial fibrillation detected on cardiac implantable electronic devices of patients at increased risk of stroke

OBJECTIVES

The objectives of this study were to evaluate the effectiveness of a physician notification system for atrial fibrillation (AF) detected on cardiac devices, and to assess predictors of anticoagulation in patients with device-detected AF.

METHODS

In 2013, a physician notification system for AF detected on a patient's CIED [including pacemakers, implantable cardioverter defibrillators (ICD) or cardiac resynchronization therapy (CRT) devices] was implemented, with a recommendation to consider oral anticoagulation in high-risk patients. We prospectively investigated the effectiveness of this system, and evaluated both patient and physician predictors of anticoagulation, as well as factors influencing physician decision making in prescribing anticoagulation. Both uni- and multivariable analysis as well as descriptive statistics were used in the analysis.

RESULTS

We identified 177 patients with device-detected AF, 126 with a CHADS2 ⩾2. Only 41% were prescribed anticoagulation at any point within 12 months. On multivariable analysis, stroke risk as predicted by CHADS2 was not a predictor of anticoagulation. ASA use predicted a lower rate of anticoagulation (OR 0.39, 95% CI 0.16-0.97, p = 0.04); physicians in practice for <20 years were more likely to prescribe anticoagulation (OR 3.39, 95% CI 1.28-8.93, p = 0.01); and physicians who believed both cardiologist and family doctor should be involved in managing anticoagulation were more likely to prescribe anticoagulation (OR 3.28, 95% CI 1.02-10.5, p = 0.05).

CONCLUSIONS

Patients on aspirin were less likely to be anticoagulated. Physicians in practice for <20 years and who believed that both the general practitioner and cardiologist should be involved in managing anticoagulants were more likely to prescribe anticoagulation.

Physician decision making in anticoagulating atrial fibrillation: a prospective survey of a physician notification system for atrial fibrillation detected on cardiac implantable electronic devices of patients at increased risk of stroke

OBJECTIVES

The objectives of this study were to evaluate the effectiveness of a physician notification system for atrial fibrillation (AF) detected on cardiac devices, and to assess predictors of anticoagulation in patients with device-detected AF.

METHODS

In 2013, a physician notification system for AF detected on a patient's CIED [including pacemakers, implantable cardioverter defibrillators (ICD) or cardiac resynchronization therapy (CRT) devices] was implemented, with a recommendation to consider oral anticoagulation in high-risk patients. We prospectively investigated the effectiveness of this system, and evaluated both patient and physician predictors of anticoagulation, as well as factors influencing physician decision making in prescribing anticoagulation. Both uni- and multivariable analysis as well as descriptive statistics were used in the analysis.

RESULTS

We identified 177 patients with device-detected AF, 126 with a CHADS2 ⩾2. Only 41% were prescribed anticoagulation at any point within 12 months. On multivariable analysis, stroke risk as predicted by CHADS2 was not a predictor of anticoagulation. ASA use predicted a lower rate of anticoagulation (OR 0.39, 95% CI 0.16-0.97, p = 0.04); physicians in practice for <20 years were more likely to prescribe anticoagulation (OR 3.39, 95% CI 1.28-8.93, p = 0.01); and physicians who believed both cardiologist and family doctor should be involved in managing anticoagulation were more likely to prescribe anticoagulation (OR 3.28, 95% CI 1.02-10.5, p = 0.05).

CONCLUSIONS

Patients on aspirin were less likely to be anticoagulated. Physicians in practice for <20 years and who believed that both the general practitioner and cardiologist should be involved in managing anticoagulants were more likely to prescribe anticoagulation.

Using an Atrial Fibrillation Decision Support Tool for Thromboprophylaxis in Atrial Fibrillation: Effect of Sex and Age

OBJECTIVES

To assess the appropriateness of oral anticoagulant therapy (OAT) in women and elderly adults, looking for patterns of undertreatment or unnecessary treatment.

DESIGN

Retrospective cohort study.

SETTING

Primary care practices of an academic healthcare system.

PARTICIPANTS

Adults (aged 28-93) with nonvalvular atrial fibrillation (AF) seen between March 2013 and February 2014 (N = 1,585).

MEASUREMENTS

Treatment recommendations were made using an AF decision support tool (AFDST) based on projections of quality-adjusted life expectancy calculated using a decision analytical model that integrates individual-specific risk factors for stroke and hemorrhage.

RESULTS

Treatment was discordant from AFDST-recommended treatment in 45% (326/725) of women and 39% (338/860) of men (P = .02). Although current treatment was discordant from recommended in 35% (89/258) of participants aged 85 and older and in 43% (575/1,328) of those younger than 85 (P = .01), many undertreated elderly adults were receiving aspirin as the sole antithrombotic agent.

CONCLUSION

Physicians should understand that female sex is a significant risk factor for AF-related stroke and incorporate this into decision-making about thromboprophylaxis. Treating older adults with aspirin instead of OAT exposes them to significant risk of bleeding with little to no reduction in AF-related stroke risk.

Improving stroke prevention therapy for patients with atrial fibrillation in primary care: protocol for a pragmatic, cluster-randomized trial

Background

The prevalence of atrial fibrillation (AF) is growing as the population ages, and at least 15% of ischemic strokes are attributed to AF. However, many high-risk AF patients are not offered guideline-recommended stroke prevention therapy due to a variety of system, provider, and patient-level barriers.

Methods

We will conduct a pragmatic, cluster-randomized controlled trial randomizing primary care clinics to test a “toolkit” of quality improvement interventions in primary care. In keeping with the recommendations of the chronic care model to simultaneously activate patients and facilitate proactive care by providers, the toolkit includes provider-focused strategies (education, audit and feedback, electronic decision support, and reminders) plus patient-directed strategies (educational letters and reminders). The trial will include two feedback cycles at baseline and approximately 6 months and a final data collection at approximately 12 months. The study will be powered to show a difference of 10% in the primary outcome of proportion of patients receiving guideline-recommended stroke prevention therapy. Analysis will follow the intention-to-treat principle and will be blind to treatment allocation. Unit of analysis will be the patient; models will use generalized estimating equations to account for clustering at the clinical level.

Discussion

Stroke prevention therapy using anticoagulation in patients with AF is known to reduce strokes by two thirds or more in clinical trials, but most studies indicate under-use of this treatment in real-world practice. If the toolkit successfully improves care for patients with AF, stakeholders will be engaged to facilitate broader application to maximize the potential to improve patient outcomes. The intervention toolkit tested in this project could also provide a model to improve quality of care for other chronic cardiovascular conditions managed in primary care.

Trial registration

ClinicalTrials.gov (NCT01927445). Registered August 14, 2014 at https://clinicaltrials.gov/.

Electronic supplementary material

The online version of this article (doi:10.1186/s13012-016-0523-2) contains supplementary material, which is available to authorized users.

Quality measures for anticoagulation care

OBJECTIVE

To systematically identify and assess current quality measures for anticoagulation in atrial fibrillation (AF), venous thromboembolism (VTE) treatment and surgical VTE prophylaxis.

RESEARCH DESIGN AND METHODS

Fifteen quality measure websites were searched as were bibliographic databases (January 2000-February 2016). Quality measures were included if developed in the United States and incorporating an aspect of anticoagulation for the aforementioned indications or if applicable but not indication specific (non-disease specific measure). Two reviewers independently extracted data regarding the characteristics of each quality measure.

RESULTS

Thirty-five measures were identified, mostly in VTE treatment (48.6%), followed by non-disease specific measures (25.7%), AF (17.6%) and surgical VTE prophylaxis (8.8%). Process measures predominated (82.9%). A majority of quality measures (65.7%) were focused on parenteral anticoagulants or warfarin and not applicable to novel oral anticoagulants (NOACs). Ten (28.6%) measures are used by the Centers for Medicare and Medicaid Services or as a core measure of The Joint Commission. Limitations include the inability to statistically pool data and possible publication bias given the nature of databases for quality measures.

CONCLUSIONS

Quality measures are recognized in anticoagulation care. Areas for improvement include expanding beyond process measures and capturing adverse events and the advantages offered by NOACs.

Impact of Warfarin on Atrial-Fibrillation Outcomes Related to Economic Consumption Patterns: Hospitalization, Cost, and Mortality may be Predictable and Modifiable at the Population Level

INTRODUCTION

Warfarin reduces atrial fibrillation (AF)-related strokes and may impact mortality, hospitalizations, and costs. This study investigated the possibility that patterns of warfarin consumption are associated with the frequency of acute events.

METHODS

Annual cost profiles of 9.2 million Medicare beneficiaries with AF were analyzed to identify patterns of benefits consumption from 2000 through 2010. Beneficiaries were divided into five consumption clusters based upon their annual cost profiles, ranging from crisis consumers at the high end to low consumers. Resource-utilization patterns and outcome differences were calculated between AF beneficiaries who received warfarin and those who did not. Propensity score-matched analysis was performed to reduce selection bias.

RESULTS

The annual percentages of beneficiaries and expenditures that differentiated each cluster showed stable patterns. Warfarin use influenced consumption patterns and outcomes. The most important financial difference between higher and lower consumers was inpatient cost. AF beneficiaries on warfarin had lower annual cost profiles and had a higher propensity to persist in or migrate to consumption clusters with comparatively small reimbursement claims and lower hospitalization risks. AF beneficiaries not on warfarin had higher cost and mortality.

CONCLUSIONS

These data signal that a nontrivial portion of acute events (hospitalization and mortality) are amenable to medical intervention (warfarin). When acute events are amenable to medical intervention and occur at a higher frequency because guidelines have not been applied evenly across affected populations, it is appropriate to define those occurrences as disparities associated with systemic failure in evidence-based medicine. Quality-improvement initiatives that reduce therapeutic disparities may result in lower cost and improved outcomes.

FUNDING

No funding or sponsorship was received for this study or publication of this article.

Anticoagulated patient's perception of their illness, their beliefs about the anticoagulant therapy prescribed and the relationship with adherence: impact of novel oral anticoagulant therapy - study protocol for The Switching Study: a prospective cohort study

Background

Anticoagulant therapy is prescribed for millions of patients worldwide for the prevention and treatment of both arterial and venous thrombosis. Historically, only vitamin K antagonists have been available for clinicians to prescribe. The anticoagulation landscape is changing. The recent availability of the novel oral anticoagulants overcome many of the disadvantages associated with vitamin K antagonists. However the lack of formal monitoring and clinic follow-up is a concern for clinicians, as medication adherence is being assumed, which is known to decline in patients prescribed medications for chronic conditions. The switching study is a programme of work investigating the association between medication adherence and patient’s beliefs about anticoagulation therapy (warfarin and subsequently novel oral anticoagulants), together with beliefs about their illness and anticoagulation related quality of life.

Methods/design

The anticoagulation database at King’s College Hospital will be interrogated and two groups of patients will be identified; those with a time in therapeutic range on warfarin of ≥75 % and those <50 %. These groups of patients will have their illness perceptions, anticoagulation specific quality of life and beliefs about medications compared. Those patients in the time in therapeutic range <50 % group, will be then be invited to switch to a novel oral anticoagulant, as per local guidance. Those patients, who do switch, will then be followed longitudinally and have their adherence, illness perceptions, anticoagulation specific quality of life and beliefs about medications, re-evaluated on the novel agent. The results from these sub-studies, will inform a clinical pathway to support patients on these novel agents, which will be evaluated in an independent group of patients.

Discussion

The results from the switching study will be used to develop a clinical pathway to support patient’s prescribed novel oral anticoagulant therapy long-term.

Electronic supplementary material

The online version of this article (doi:10.1186/s12878-016-0061-9) contains supplementary material, which is available to authorized users.

Prescribers' behavior following below- versus above-range international normalized ratio values in warfarin-treated deep vein thrombosis patients

Maintaining acceptable international normalized ratio (INR) control among deep vein thrombosis (DVT) patients taking warfarin is challenging. We evaluated prescribers' behavior to out-of-range INRs in DVT patients following initial INR stabilization. Following INR stabilization, a below-range INR was associated with fewer subsequent measurements and warfarin-dosing adjustments, and a longer time to re-achieve a therapeutic INR compared to an above-range INR.

Using Clinical Vignettes to Assess Quality of Care for Acute Respiratory Infections

Overprescribing of antibiotics for acute respiratory infections (ARIs) is common. Our objective was to develop and validate a vignette-based method to estimate clinician ARI antibiotic prescribing. We surveyed physicians (n = 78) and retail clinic clinicians (n = 109) between January and September 2013. We surveyed clinicians using a set of ARI vignettes and linked the responses to electronic health record data for all ARI visits managed by these clinicians during 2012. We then created a new measure of antibiotic prescribing, the comprehensive ARI management rate. This was defined as not prescribing antibiotics for antibiotic-inappropriate diagnoses and prescribing guideline-concordant antibiotics for antibiotic-appropriate diagnoses (and also included appropriate use of streptococcal testing for the pharyngitis vignettes). We compared the vignette-based and chart-based comprehensive ARI management at the clinician level. We then identified the combination of vignettes that best predicted comprehensive ARI management rates, using a partitioning algorithm. Responses to 3 vignettes partitioned clinicians into 4 groups with chart-based comprehensive ARI management rates of 61% (n = 121), 50% (n = 47), 31% (n = 12), and 22% (n = 7). Responses to 3 clinical vignettes can identify clinicians with relatively poor quality ARI antibiotic prescribing. Vignettes may be a mechanism to target clinicians for quality improvement efforts.

Incidence and Determinants of Traumatic Intracranial Bleeding Among Older Veterans Receiving Warfarin for Atrial Fibrillation

IMPORTANCE

Traumatic intracranial bleeding, which is most commonly attributable to falls, is a common concern among health care professionals, who are hesitant to prescribe oral anticoagulants to older adults with atrial fibrillation.

OBJECTIVE

To describe the incidence of and risk factors for traumatic intracranial bleeding in a large cohort of older adults who were newly prescribed warfarin sodium.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study at the US Department of Veterans Affairs (VA). Participants included 31 951 veterans with atrial fibrillation 75 years or older who were new referrals to VA anticoagulation clinics (for warfarin therapy) between January 1, 2002, and December 31, 2012. The dates of the core analysis were March 2014 through May 2015, and subsequent ad hoc analyses were performed through December 2015. Patients with comorbid conditions requiring warfarin were excluded.

MAIN OUTCOMES AND MEASURES

The primary outcome was hospitalization for traumatic intracranial bleeding. Secondary outcomes included hospitalization for any intracranial bleeding or ischemic stroke. We used International Classification of Diseases, Ninth Revision, Clinical Modification codes to identify the incidence rates of these outcomes after warfarin initiation using VA administrative data (in-system hospitalizations) and Medicare fee-for-service claims data (out-of-system hospitalizations). Clinical characteristics, laboratory results, and pharmacy data were extracted from the VA electronic medical record. For traumatic intracranial bleeding, Cox proportional hazards regression was used to determine predictors of interest selected a priori based on prior known associations.

RESULTS

The study population comprised 31 951 participants. The mean (SD) patient age was 81.1 (4.1) years, and 98.1% were male. Comorbidities were common, including hypertension (82.5%), coronary artery disease (42.6%), and diabetes mellitus (33.8%). During the study period, the incidence rate of hospitalization for traumatic intracranial bleeding was 4.80 per 1000 person-years. In unadjusted models, significant predictors of traumatic intracranial bleeding included dementia, fall within the past year, anemia, depression, abnormal renal or liver function, anticonvulsant use, labile international normalized ratio, and antihypertensive use. After adjusting for potential confounders, the remaining significant predictors for traumatic intracranial bleeding were dementia (hazard ratio [HR], 1.76; 95% CI, 1.26-2.46), anemia (HR, 1.23; 95% CI, 1.00-1.52), depression (HR, 1.30; 95% CI, 1.05-1.61), anticonvulsant use (HR, 1.35; 95% CI, 1.04-1.75), and labile international normalized ratio (HR, 1.33; 95% CI, 1.04-1.72). The incidence rates of hospitalization for any intracranial bleeding and ischemic stroke were 14.58 and 13.44, respectively, per 1000 person-years.

CONCLUSIONS AND RELEVANCE

Among patients 75 years or older with atrial fibrillation initiating warfarin therapy, the risk factors for traumatic intracranial bleeding are unique from those for ischemic stroke. The high overall rate of intracranial bleeding in our sample supports the need to more systematically evaluate the benefits and harms of warfarin therapy in older adults.

Device-Detected Atrial Fibrillation-Perils and Pitfalls: An Update

Stroke and thromboembolism are catastrophic complications of atrial fibrillation (AF). Cardiac implantable electronic devices (CIED) with an atrial lead can reliably detect atrial high-rate events (AHRE). However, this correlation may be imperfect because of oversensing and undersensing of atrial signals and spurious arrhythmias. The critical duration, frequency, or overall burden of AHRE that increases stroke risk is still unknown; thus, the threshold level of AHRE (duration and frequency) that warrants anticoagulation in patients with CIED-detected AHRE is still unclear. This article reviews current literature on the risk of stroke with CIED-detected AHRE and raises questions that need further clarification.

Evaluating the Usability and Perceived Impact of an Electronic Medical Record Toolkit for Atrial Fibrillation Management in Primary Care: A Mixed-Methods Study Incorporating Human Factors Design

BACKGROUND

Atrial fibrillation (AF) is a common and preventable cause of stroke. Barriers to reducing stroke risk through appropriate prescribing have been identified at the system, provider, and patient levels. To ensure a multifaceted initiative to address these barriers is effective, it is essential to incorporate user-centered design to ensure all intervention components are optimized for users.

OBJECTIVE

To test the usability of an electronic medical record (EMR) toolkit for AF in primary care with the goal of further refining the intervention to meet the needs of primary care clinicians.

METHODS

An EMR-based toolkit for AF was created and optimized through usability testing and iterative redesign incorporating a human factors approach. A mixed-methods pilot study consisting of observations, semi-structured interviews, and surveys was conducted to examine usability and perceived impact on patient care and workflow.

RESULTS

A total of 14 clinicians (13 family physicians and 1 nurse practitioner) participated in the study. Nine iterations of the toolkit were created in response to feedback from clinicians and the research team; interface-related changes were made, additional AF-related resources were added, and functionality issues were fixed to make the toolkit more effective. After improvements were made, clinicians expressed that the toolkit improved accessibility to AF-related information and resources, served as a reminder for guideline-concordant AF management, and was easy to use. Most clinicians intended to continue using the toolkit for patient care. With respect to impact on care, clinicians believed the toolkit increased the thoroughness of their assessments for patients with AF and improved the quality of AF-related care received by their patients.

CONCLUSIONS

The positive feedback surrounding the EMR toolkit for AF and its perceived impact on patient care can be attributed to the adoption of a user-centered design that merged clinically important information about AF management with user needs. This study demonstrates the utility of a human factors approach to piloting and refining an intervention prior to wide-scale implementation.

Variation in Anticoagulant Recommendations by the Guidelines and Decision Tools among Patients with Atrial Fibrillation

Published atrial fibrillation (AF) guidelines and decision tools offer oral anticoagulant (OAC) recommendations; however, they consider stroke and bleeding risk differently. The aims of our study are: (i) to compare the variation in OAC recommendations by the 2012 American College of Chest Physicians guidelines, the 2012 European Society of Cardiology (ESC) guidelines, the 2014 American Heart Association (AHA) guidelines and two published decision tools by Casciano and LaHaye; (ii) to compare the concordance with actual OAC use in the overall study population and the population stratified by stroke/bleed risk. A cross-sectional study using the 2001–2013 Lifelink claims data was used to contrast the treatment recommendations by these decision aids. CHA₂DS₂-VASc and HAS-BLED algorithms were used to stratify 15,129 AF patients into nine stroke/bleed risk groups to study the variation in treatment recommendations and concordance with actual OAC use/non-use. The AHA guidelines which were set to recommend OAC when CHA₂DS₂-VASc = 1 recommended OAC most often (86.30%) and the LaHaye tool recommended OAC the least often (14.91%). OAC treatment recommendations varied considerably when stroke risk was moderate or high (CHA₂DS₂-VASc > 0). Actual OAC use/non-use was highly discordant (>40%) with all of the guidelines or decision tools reflecting substantial opportunities to improve AF OAC decisions.

The prestroke use of vitamin K antagonists for atrial fibrillation - trends over 15 years

BACKGROUND

Effective anticoagulation with vitamin K antagonists (VKAs) is the standard of stroke prevention in patients with non-valvular atrial fibrillation (AF). Although, everyday practice is becoming increasingly guideline-driven, proper anticoagulation is still problematic. We aimed to investigate changes in the use of VKAs for stroke prevention in patients with AF admitted because of acute stroke over a period of 15 years.

METHODS

We analysed consecutive acute stroke patients admitted to our centre between June 1995 and December 2010. Data were prospectively collected in a detailed stroke registry. We distinguished between three periods: 1995-2000 (used as reference for comparisons), 2001-2005 and 2006-2010.

RESULTS

The AF rate prior to stroke was similar in ischaemic stroke patients (1995-2000: 25%, 2001-2005: 24%, 2006-2010: 24%) but increased in patients with intracerebral haemorrhage (ICH) (6%, 11%, 19%, p = 0.003 since 2006). The proportion of patients with AF using VKAs before stroke has became higher in ischaemic stroke (10%, 16%, 28%, p < 0.001 since 2006) with non-significant trend in ICH (0%, 33%, 45%). The proportion of ischaemic strokes occurring in patients with AF using VKAs with INR < 2 tended to increase over time (58%, 83%, 80.3%). There was also tendency towards increasing proportion of ICHs occurring in patients with AF over treated with VKAs (INR > 3).

CONCLUSIONS

The prescription rate of VKA for stroke prevention appears to be improving. However, because of a high proportion of patients on non-therapeutic INR, the proportion of cardioembolic ischaemic strokes remains stable. It may suggest that everyday use of VKAs is still far from optimal.

Could some geriatric characteristics hinder the prescription of anticoagulants in atrial fibrillation in the elderly?

Several studies have reported underprescription of anticoagulants in atrial fibrillation (AF). We conducted an observational study on 142 out of a total of 995 consecutive ≥75 years old patients presenting AF (14%) when admitted in an emergency unit of a general hospital, in search of geriatric characteristics that might be associated with the underprescription of anticoagulation therapy (mostly antivitamin K at the time of the study). The following data was collected from patients presenting AF: medical history including treatment and comorbidities, CHADS2 score, ISAR scale (frailty), Lawton's scale (ADL), GDS scale (mood status), MUST (nutrition), and blood analysis (INR, kidney function, and albumin). Among those patients for who anticoagulation treatment was recommended (73%), only 61% were treated with it. In the group with anticoagulation therapy, the following characteristics were observed more often than in the group without such therapy: a recent (≤6 months) hospitalization and medical treatment including digoxin or based on >3 different drugs. Neither the value of the CHADS2 score, nor the geriatric characteristics could be correlated with the presence or the absence of an anticoagulation therapy. More research is thus required to identify and clarify the relative importance of patient-, physician-, and health care system-related hurdles for the prescription of oral anticoagulation therapy in older patients with AF.

Left atrial appendage exclusion for prevention of stroke in atrial fibrillation: review of minimally invasive approaches

Stroke prevention is of vital importance in the management of atrial fibrillation (AF), though the proven strategy of systemic anticoagulation for thromboembolic prophylaxis is underutilized for a variety of reasons. The left atrial appendage (LAA) has long been suspected as the principal source of arterial emboli, particularly in nonvalvular AF, and a variety of techniques for its exclusion from the circulation have been developed. This review highlights the history of the LAA as a target of intervention, and the parallel advances in three minimally invasive strategies for its exclusion: percutaneous occlusion of the LAA orifice from within the left atrium, closed-chest ligation via a percutaneous pericardial approach, and minimally invasive thoracoscopic surgery. While further study is necessary, available evidence suggests that effective LAA exclusion is becoming a viable alternative to anticoagulation for stroke prevention in nonvalvular AF.

Characteristics affecting oral anticoagulant therapy choice among patients with non-valvular atrial fibrillation: a retrospective claims analysis

Background

Dabigatran is one of the three newer oral anticoagulants (OACs) recently approved in the United States for stroke prevention in non-valvular atrial fibrillation (NVAF) patients. The objective of this study was to identify patient, healthcare provider, and health plan factors associated with dabigatran versus warfarin use among NVAF patients.

Methods

Administrative claims data from patients with ≥2 NVAF medical claims in the HealthCore Integrated Research Database between 10/1/2009 and 10/31/2011 were analyzed. During the study intake period (10/1/2010 - 10/31/2011), dabigatran patients had ≥2 dabigatran prescriptions, warfarin patients had ≥2 warfarin and no dabigatran prescriptions, and the first oral anticoagulant (OAC) prescription date was the index date. Continuous enrollment for 12 months preceding (“pre-index”) and ≥ 6 months following the index date was required. Patients without pre-index warfarin use were assigned to the ‘OAC-naïve’ subgroup. Separate analyses were performed for ‘all-patient’ and ‘OAC-naïve’ cohorts. Multivariable logistic regression (LR) identified factors associated with dabigatran versus warfarin use.

Results

Of 20,320 patients (3,019 dabigatran and 17,301 warfarin) who met study criteria, 27% of dabigatran and 13% of warfarin patients were OAC-naïve. Among all-patients, dabigatran patients were younger (mean 67 versus 73 years, p < 0.001), predominantly male (71% versus 61%, p < 0.001), and more frequently had a cardiologist prescriber (51% versus 30%, p < 0.001) than warfarin patients. Warfarin patients had higher pre-index Elixhauser Comorbidity Index (mean: 4.3 versus 4.0, p < 0.001) and higher ATRIA bleeding risk score (mean: 3.0 versus 2.3, p < 0.001). LR results were generally consistent between all- and OAC-naïve patients. Among OAC-naïve patients, strongest factors associated with dabigatran use were prescriber specialty (OR = 3.59, 95% CI 2.68-4.81 for cardiologist; OR = 2.22, 95% CI 1.65-2.97 for other specialist), health plan type (OR = 1.47 95% CI 1.10-1.96 for preferred provider organization), and prior ischemic stroke (OR = 1.42, 95% CI 1.06-1.90). Older age decreased the probability of dabigatran use.

Conclusions

Beside patient characteristics, cardiology specialty of the prescribing physician and health plan type were the strongest factors associated with dabigatran use.

Risk scores and geriatric profile: can they really help us in anticoagulation decision making among older patients suffering from atrial fibrillation?

OBJECTIVES

Anticoagulation for the prevention of cardio-embolism is most frequently indicated but largely underused in frail older patients with atrial fibrillation (AF). This study aimed at identifying characteristics associated with anticoagulation underuse.

METHODS

A cross-sectional study of consecutive geriatric patients aged ≥75 years, with AF and clear anticoagulation indication (CHADS₂ [Congestive heart failure, Hypertension, Age >75, Diabetes mellitus, and prior Stroke or transient ischemic attack] ≥2) upon hospital admission. All patients benefited from a comprehensive geriatric assessment. Their risks of stroke and bleeding were predicted using CHADS₂ and HEMORR2HAGES (Hepatic or renal disease, Ethanol abuse, Malignancy, Older (age >75 years), Reduced platelet count or function, Rebleed risk, Hypertension (uncontrolled), Anemia, Genetic factors, Excessive fall risk, and Stroke) scores, respectively.

RESULTS

Anticoagulation underuse was observed in 384 (50%) of 773 geriatric patients with AF (median age 85 years; female 57%, cognitive disorder 33%, nursing home 20%). No geriatric characteristic was found to be associated with anticoagulation underuse. Conversely, anticoagulation underuse was markedly increased in the patients treated with aspirin (odds ratio [OR] [95% confidence interval]: 5.3 [3.8; 7.5]). Other independent predictors of anticoagulation underuse were ethanol abuse (OR: 4.0 [1.4; 13.3]) and age ≥90 years (OR: 2.0 [1.2; 3.4]). Anticoagulation underuse was not inferior in patients with a lower bleeding risk and/or a higher stroke risk and underuse was surprisingly not inferior either in the AF patients who had previously had a stroke.

CONCLUSION

Half of this geriatric population did not receive any anticoagulation despite a clear indication, regardless of their individual bleeding or stroke risks. Aspirin use is the main characteristic associated with anticoagulation underuse.

Impact of stated barriers on proposed warfarin prescription for atrial fibrillation: a survey of Canadian physicians

BACKGROUND

Atrial fibrillation (AF) is a common cardiac arrhythmia, and leading cause of ischemic stroke. Despite proven effectiveness, warfarin remains an under-used treatment in atrial fibrillation patients. We sought to study, across three physician specialties, a range of factors that have been argued to have a disproportionate effect on treatment decisions.

METHODS

Cross-sectional survey of Canadian Family Doctors (FD: n = 500), Geriatricians (G: n = 149), and Internal Medicine specialists (IMS: n = 500). Of these, 1032 physicians were contactable, and 335 completed and usable responses were received. Survey questions and clinical vignettes asked about the frequency with which they see patients with atrial fibrillation, treatment practices, and barriers to the prescription of anticoagulants.

RESULTS

Stated prescribing practices did not significantly differ between physician groups. Falls risk, bleeding risk and poor patient adherence were all highly cited barriers to prescribing warfarin. Fewer geriatricians indicated that history of patient falls would be a reason for not treating with warfarin (G: 47%; FD: 71%; IMS: 72%), and significantly fewer changed reported practice in the presence of falls risk (χ (2) (6) = 45.446, p < 0.01). Experience of a patient having a stroke whilst not on warfarin had a significant impact on vignette decisions; physicians who had had patients who experienced a stroke were more likely to prescribe warfarin (χ (2) (3) =10.7, p = 0.013).

CONCLUSIONS

Barriers to treatment of atrial fibrillation with warfarin affect physician specialties to different extents. Prior experience of a patient suffering a stroke when not prescribed warfarin is positively associated with intention to prescribe warfarin, even in the presence of falls risk.

Stroke and Bleeding Risks in Patients with Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with a substantial risk of stroke and mortality. Strokes in patients with AF are associated with a greater disability and poorer outcomes than strokes in patients in sinus rhythm. Patients with AF are at increased risk of bleeding, especially if they use anticoagulant therapy. Recent research in the field of anticoagulation has led to development of new anticoagulants for stroke prevention in addition to antiplatelet agents and warfarin. This review discusses the role of AF as a risk factor for stroke and evaluates the role of various schemes for predicting the risk of stroke and bleeding in patients with AF.

A non-experimental study of oral anticoagulation therapy initiation before and after national patient safety goals

OBJECTIVES

The Joint Commission revised its National Patient Safety Goals (NPSGs) to include oral anticoagulation therapy (OAT) in 2008. We sought to examine the effect of including OAT in The Joint Commission's NPSGs on historically low rates of OAT initiation for individuals with incident atrial fibrillation (AF).

SETTING

Southeastern state in the USA.

PARTICIPANTS

North Carolina State Health Plan claims data from 944 500 individuals enrolled between 1 January 2006 and 31 December 2010, supplemented with data from the Area Resource File and Online Survey, Certification and Reporting data network. We evaluated OAT initiation before and after the 2008 NPSGs revisions in a retrospective cohort new user design with an AF intervention group and two control groups: a positive control-patients estimated to be at very high risk of thromboembolism (mechanical heart valve and pulmonary embolism); and a negative control-patients with very low perceived risk of thromboembolism (paroxysmal AF). We developed multivariable models using a difference-in-difference parameterisation. Effects were estimated with generalised estimating equations.

PRIMARY OUTCOME MEASURE

OAT initiation, a binary outcome defined as having a prescription drug claim for warfarin within 30 days of the index claim.

RESULTS

OAT initiation was low (26.8%) for eligible individuals with incident AF in 2006-2008 but increased after NPSGs implementation (31.7%, p=0.022). OAT initiation was high but decreased in the positive control group (67.5% vs 62.0%, p=0.003). Multivariate analysis resulted in a relative 11% (95% CI (4% to 18%), p<0.01) increase in OAT initiation for incident AF patients.

CONCLUSIONS

We document a substantial increase in guideline concordant OAT initiation in incident AF after the establishment of NPSGs, suggesting that regulatory healthcare agency initiatives can influence clinical practice.

A cluster-randomized controlled trial of a computerized antithrombotic risk assessment tool to optimize stroke prevention in general practice: a study protocol

BACKGROUND

Therapy for stroke prevention in older persons with atrial fibrillation (AF) is underutilized despite evidence to support its effectiveness. To prevent stroke in this high-risk population, antithrombotic treatment is necessary. Given the challenges and inherent risks of antithrombotic therapy, decision-making is particularly complex for clinicians, necessitating comprehensive risk:benefit assessments. Targeted interventions are urgently needed to support clinicians in this context; the Computerized Antithrombotic Risk Assessment Tool (CARAT) offers a unique approach to this clinical problem.

METHODS/DESIGN

This study (a prospective, cluster-randomized controlled clinical trial) will be conducted across selected regions in the state of New South Wales, Australia. Fifty GPs will be randomized to either the 'intervention' or 'control' arm, with each GP recruiting 10 patients (aged ≥65 with AF); target sample size is 500 patients. GPs in the intervention arm will use CARAT during routine patient consultations to: assess risk factors for stroke, bleeding and medication misadventure; quantify the risk/benefit ratio of antithrombotic treatment, identify the recommended therapy, and decide on the treatment course, for an individual patient. CARAT will be applied by the GP at baseline and repeated at 12 months to identify any changes to treatment requirements. At baseline, the participant (patients and GPs) characteristics will be recorded, as well as relevant practice and clinical parameters. Patient follow up will occur at 1, 6, and 12 months via telephone interview to identify changes to therapy, medication side effects, or clinical events.

DISCUSSION

This project tests the utility of a novel decision support tool (CARAT) in improving the use of preventative therapy to reduce the significant burden of stroke. Importantly, it targets the interface of patient care (general practice), addresses the at-risk population, evaluates clinical outcomes, and offers a tool that may be sustainable via integration into prescribing software and primary care services. GP support and guidance in identifying at risk patients for the appropriate selection of therapy is widely acknowledged. This trial will evaluate the impact of CARAT on the prescription of antithrombotic therapy, its longer-term impact on clinical outcomes including stroke and bleeding, and clinicians perceived utility of CARAT in practice.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12613000060741.

Factors associated with undertreatment of atrial fibrillation in geriatric outpatients with Alzheimer disease

BACKGROUND

According to international recommendations [from the American College of Cardiology/American Heart Association/European Society of Cardiology] and those of the Haute Autorité de Santé (HAS) in France, treatment with a vitamin K antagonist is recommended in patients with atrial fibrillation (AF) in the presence of a high thromboembolic risk factor [history of stroke, transient ischemic attack, systemic embolism, or valvular heart disease, or presence of a mechanical heart valve prosthesis] or at least two moderate risk factors (age ≥75 years, hypertension, congestive heart failure, or diabetes). In patients with a major contraindication, the vitamin K antagonist can be replaced by an antiplatelet agent (APA). These recommendations are not systematically observed in patients with Alzheimer disease (AD). The aim of our study was to determine the factors associated with undertreatment of AF in geriatric outpatients with AD.

METHODS

Use of oral anticoagulants or APAs was studied in 66 patients with AF who were included in the French Network on Alzheimer Disease (REAL.FR) cohort, consisting of 686 outpatients living at home, supported by an informal caregiver, and suffering from Alzheimer-type dementia, with a Mini Mental Status Examination (MMSE) score between 10 and 26. First, demographic characteristics (age, sex, body mass index [BMI], living arrangements, educational level), medical conditions (comorbidity, number of medications), disability (activities of daily living [ADL], instrumental activities of daily living [IADL]), risk of falls (one-leg balance test), cognitive status (according to MMSE, Alzheimer's Disease Assessment Scale-Cognitive Subscale [ADAS-Cog], and Clinical Dementia Rating [CDR] scores), risk factors for stroke (hypertension, history of stroke, congestive heart failure, diabetes, or age ≥75 years) and potential contraindications to oral anticoagulants (OACs) or APAs (polypharmacy, risk of falls, renal failure, gastrointestinal diseases) of patients receiving OACs were compared with those of patients receiving APAs and those of patients receiving no treatment for AF. Then the same characteristics were compared between patients receiving no treatment for AF and those receiving OACs or APAs.

RESULTS

Only 56 % (n = 37) of patients with AF were receiving OACs or APAs at the baseline visit, of whom 18 (49 %) were receiving OACs and 19 (51 %) were receiving APAs. Bivariate analysis showed that patients receiving OACs or APAs were significantly more likely to have a history of cardiovascular disease (p = 0.005)-in particular, hypertension (p = 0.037)-less likely to be living alone and unaided (p = 0.038), and less likely to be taking nonsteroidal anti-inflammatory drugs [NSAIDs] (p = 0.001).

CONCLUSION

Despite the national and international recommendations, nearly half of AD patients with AF do not receive OACs or APAs. A history of cardiovascular disease-in particular, hypertension-improves access to treatment, but use of NSAIDs and living alone without home care seem to be the main factors associated with non-prescription of OACs or APAs.

Patient-centered medical homes and oral anticoagulation therapy initiation

Despite evidence-based guidelines, oral anticoagulation therapy (OAT) initiation is low among incident atrial fibrillation (AF) patients. Patient-centered medical homes (PCMHs) may increase access, quality, and value through coordinating care. As such, PCMHs hold potential for improving OAT initiation among AF patients. We estimated the effect of receiving care in accredited PCMHs on OAT initiation for incident AF patients compared with those not receiving care in accredited PCMHs. Our study, a retrospective cohort new user design, included privately insured patients in North Carolina during years 2006 to 2010. We developed propensity scores for PCMH exposure, performed inverse probability of treatment weighting, and estimated effects with generalized estimating equations. We found a positive association between PCMH exposure and OAT initiation in unadjusted (6.78%; p < .001) and adjusted (6.25%; p < .001) models. Greater implementation and optimization of PCMH model principles may enhance this association, reducing AF-related stroke morbidity and mortality.

A Pharmacokinetic Study of the Combined Administration of Amiodarone and Ximelagatran, an Oral Direct Thrombin Inhibitor

The oral direct thrombin inhibitor ximelagatran is being developed for the prevention and treatment of thromboembolism. This single-blind, randomized, placebo-controlled, parallel-group study investigated the potential for the interaction of ximelagatran (36 mg every 12 hours for 8 days, measured as its active form melagatran in blood) and amiodarone (single 600-mg oral dose on day 4) in healthy male subjects (n = 26). For amiodarone + ximelagatran versus amiodarone + placebo, geometric mean ratios (90% confidence intervals for amiodarone AUC(0-120) and C(max) were 0.87 (0.69-1.08) and 0.86 (0.66-1.11), respectively. For desethylamiodarone, the principal metabolite of amiodarone, the corresponding ratios were 1.00 (0.89-1.12) for AUC(0-120) and 0.92 (0.77-1.09) for C(max). The geometric mean ratios (90% confidence intervals) for ximelagatran + amiodarone versus ximelagatran were 1.21 (1.17-1.25) for melagatran AUC(0-12) and 1.23 (1.18-1.28) for melagatran C(max). These confidence intervals were within or only slightly outside the interval, suggesting no interaction (0.8-1.25 for the effect of amiodarone on melagatran and 0.7-1.43 for the effect of melagatran on amiodarone or desethylamiodarone). Amiodarone did not affect the concentration-effect relationship of melagatran on activated partial thromboplastin time. Ximelagatran was well tolerated when coadministered with a single dose of amiodarone. Evaluation of the safety of the combination is needed to confirm that the relatively small pharmacokinetic changes in this study are of no clinical significance.

Anticoagulation therapy for patients with non-valvular atrial fibrillation: comparison of decision analytic model recommendations and real-world warfarin prescription use

BACKGROUND

Anticoagulation in patients with atrial fibrillation (AF) is challenging because stroke-risk reduction must be balanced against increased bleeding risk.

OBJECTIVE

We developed a decision model integrating both stroke and bleeding risk schemes to guide optimal use of anticoagulation in AF, and compared model recommendations with warfarin use in a real-world database.

METHODS

A Markov model based on demographics, CHADS(2) (Congestive Heart Failure, Hypertension, Age of 75 years and greater, Diabetes Mellitus and History of Stroke) stroke and ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation) bleed risk scores, and anticoagulation treatment effects from clinical trials simulated health state transitions for recently diagnosed AF patients. The model recommended the treatment with greater quality-adjusted life expectancy. Model recommendations were contrasted with actual warfarin use recorded in the Thomson Reuters MarketScan database (N = 64,946).

RESULTS

74.8% (n = 48,548) of the Marketscan AF cohort had CHADS(2) ≥1, of whom 14.3% had moderate/high (≥4) ATRIA bleeding risk. While the model recommended warfarin for almost all patients with CHADS(2) ≥1 who are at low bleeding risk, it recommended warfarin for fewer patients as bleeding risk increased. Of the 44,611 patients recommended warfarin, 63.4% of patients were considered warfarin exposed (concordant with model recommendation), and of the 20,335 patients recommended aspirin (acetylsalicylic acid), 59.7% received warfarin (discordant with model recommendations). Actual warfarin use decreased modestly with higher stroke risk (p < 0.0001) and with higher bleeding risk (p < 0.0001).

CONCLUSION

High discordance between actual warfarin use and model recommendations suggests that anticoagulation decisions are not based on systematic evaluation of stroke and bleeding risks. Model-based clinical decision aids may improve oral anticoagulation decisions by more systematically weighing bleed and stroke risk.

Predictors of warfarin use in atrial fibrillation in the United States: a systematic review and meta-analysis

BACKGROUND

Despite warfarin's marked efficacy, not all eligible patients receive it for stroke prevention in AF. The aim of this meta-analysis was to evaluate the association between prescriber and/or patient characteristics and subsequent prescription of warfarin for stroke prevention in patients with atrial fibrillation (AF).

METHODS

Observational studies conducted in the US using multivariate analysis to determine the relationship between characteristics and the odds of receiving warfarin for stroke prevention were identified in MEDLINE, EMBASE and a manual review of references. Effect estimates of prescriber and/or patient characteristics from individual studies were pooled to calculate odds ratios (ORs) with 95% confidence intervals.

RESULTS

Twenty-eight studies reporting results of 33 unique multivariate analyses were identified. Warfarin use across studies ranged from 9.1%-79.8% (median=49.1%). There was a moderately-strong correlation between warfarin use and year of study (r=0.60, p=0.002). Upon meta-analysis, characteristics associated with a statistically significant increase in the odds of warfarin use included history of cerebrovascular accident (OR=1.59), heart failure (OR=1.36), and male gender (OR=1.12). Those associated with a significant reduction in the odds of warfarin use included alcohol/drug abuse (OR=0.62), perceived barriers to compliance (OR=0.87), contraindication(s) to warfarin (OR=0.81), dementia (OR=0.32), falls (OR=0.60), gastrointestinal hemorrhage (OR=0.47), intracranial hemorrhage (OR=0.39), hepatic (OR=0.59), and renal impairment (OR=0.69). While age per 10-year increase (OR=0.78) and advancing age as a dichotomized variable (cut-off varied by study) (OR=0.57) were associated with significant reductions in warfarin use; qualitative review of results of studies evaluating age as a categorical variable did not confirm this relationship.

CONCLUSIONS

Warfarin use has increased somewhat over time. The decision to prescribe warfarin for stroke prevention in atrial fibrillation is based upon multiple prescriber and patient characteristics. These findings can be used by family practice prescribers and other healthcare decision-makers to target interventions or methods to improve utilization of warfarin when it is indicated for stroke prevention.

Attitudes of physicians regarding anticoagulation for atrial fibrillation: a systematic review

BACKGROUND

the efficacy of warfarin for prevention of stroke in patients with atrial fibrillation (AF) is well established, but many people with AF who would benefit from warfarin are not receiving it. This systematic review aims to determine physicians' attitudes to the prescription of warfarin for AF, and identify reasons for its underuse.

METHODS

an electronic search of MEDLINE (1950-present), EMBASE (1980-present), CINAHL (1994-present), PsycINFO (1987-present) and Web of Knowledge (1970-present) was performed in November 2010 to identify all studies which addressed, via survey, physicians' attitudes regarding anticoagulation for patients with AF.

RESULTS

a total of 1,375 citations were identified. Of these citations, 44 full text studies were obtained for scrutinisation; 14 of these studies were rejected leaving 30 studies which were included in the review. All included studies were cross-sectional surveys and addressed physicians' opinions of anticoagulation in AF as a primary or secondary aim. Increasing age, increased bleeding risk, previous bleeds, falls risk, co-morbidities and ability to comply with treatment influenced whether physicians would prescribe anticoagulation for AF.

CONCLUSION

physicians are reticent to recommend warfarin for elderly patients in AF, despite evidence of increased benefit in these patients compared with younger patients. Risk of falls and previous bleeding were also shown to be disproportionate barriers to warfarin prescription. Further studies are required to determine how best to overcome these perceived barriers to appropriate anticoagulation.

Left Atrial Appendage Closure in Atrial Fibrillation: A World without Anticoagulation?

Atrial Fibrillation (AF) is a common arrhythmia with an incidence that is as high as 10% in the elderly population. Given the large proportion of strokes caused by AF as well as the associated morbidity and mortality, reducing stroke burden is the most important part of AF management. While warfarin significantly reduces the risk of AF-related stroke, perceived bleeding risks and compliance limit its widespread use in the high-risk AF population. The left atrial appendage is believed to be the “culprit” for thrombogenesis in nonvalvular AF and is a new therapeutic target for stroke prevention. The purpose of this review is to explore the evolving field of percutaneous LAA occlusion. After briefly highlighting the risk of stroke with AF, problems with warfarin, and the role of the LAA in clot formation, this article discusses the feasibility and efficacy of various devices which have been developed for percutaneous LAA occlusion.

Recent progress in antithrombotic therapy for atrial fibrillation

Atrial fibrillation (AF) is becoming a major health care burden as elderly populations increase. The increased risk of stroke and thromboembolisms in patients with AF is well documented and anti-coagulation with adjusted-dose warfarin is highly effective in reducing stroke risk, being superior to antiplatelet agents. Despite recognition of the epidemiological problem and the sound evidence base for thromboprophylaxis, as well as major guidelines recommending treatment, anticoagulation use is still suboptimal, given the dis-utility and limitations associated with warfarin. Recent developments in thromboprophylaxis for AF include efforts for better risk stratification for predictions of thromboembolic risk. Constant efforts are underway to develop newer, less cumbersome, alternatives to warfarin with similar (or better) efficacy. This review article provides an overview of the recent progress made, the potential challenges involved and the future of these therapeutic approaches.

Predictors of warfarin use in atrial fibrillation patients in the inpatient setting

BACKGROUND

There is substantial published evidence that warfarin reduces the risk of stroke in patients with atrial fibrillation (AF). However, the current literature suggests that not all patients who could benefit from warfarin receive the drug.

OBJECTIVE

To evaluate patient-related demographic and clinical factors that could influence warfarin use or other anticoagulant use in hospitalized patients with AF.

STUDY DESIGN

Retrospective observational study using claims data from the Wolters Kluwer Pharma Solutions Hospital Patient Level Database, evaluating characteristics of patients hospitalized in the US between 1 November 2003 and 31 October 2004.

SETTING

Hospital care.

PATIENTS

The study included 44,193 patients aged >or=40 years who were hospitalized between 1 November 2003 and 31 October 2004 and had a diagnosis of AF during hospitalization (AF did not need to be the cause of hospitalization).

INTERVENTIONS

Use of warfarin or other anticoagulants (unfractionated heparin [UFH] or low-molecular-weight heparin [LMWH]) was evaluated.

MAIN OUTCOME MEASURES

A logistic regression model was used to identify factors associated with warfarin use, international normalized ratio (INR) monitoring, or the use of anticoagulants (UFH or LMWH).

RESULTS

In this analysis of hospitalized patients with AF in the real-world setting, about 56% of patients received anticoagulation therapy with warfarin. Elderly patients aged >or=75 years were less likely to be treated with warfarin than younger patients, but patients between the ages of 60 and 74 years were more likely to use warfarin than their younger counterparts. Except for patients with congestive heart failure or vascular malformation, patients with other bleeding risk factors (hepatic disease, renal disease, aspirin use, and fractures) were significantly less likely to receive warfarin than those without these risk factors. CHADS(2) scores for stroke risk of 2 and 3 were associated with a significantly higher likelihood of warfarin treatment than scores of 0 or 1. Patients admitted through a routine admission (an outpatient department) were significantly more likely to be prescribed warfarin than patients admitted through an emergency room. Patients aged >or=75 years and aspirin users were more likely to have their INR monitored during hospitalization. With respect to other anticoagulant use, females and older patients (>or=65 years) were less likely to use UFH or LMWH, and patients with renal disease or vascular malformation and those receiving aspirin were more likely to use UFH or LMWH than patients without these conditions/not receiving aspirin. Patients admitted through the emergency room were more likely to receive an anticoagulant than patients admitted through an outpatient department, an inpatient transfer, or any other source.

CONCLUSIONS

Older age, female sex, and certain risk factors for bleeding, including hepatic disease, renal disease, aspirin use, and fractures, were associated with a lower likelihood of warfarin treatment, while a higher stroke risk (as indicated by CHADS(2) scores) was associated with a higher likelihood of warfarin treatment, in hospitalized patients with a diagnosis of AF. The likelihood of INR being monitored increased for patients aged >or=75 years and for aspirin users. Older patients and female patients were less likely to be prescribed other anticoagulants (UFH or LMWH) also.

Examining warfarin underutilization rates in patients with atrial fibrillation: Detailed chart review essential to capture contraindications to warfarin therapy

Introduction

Atrial fibrillation affects an estimated 2.5 million Americans and incurs an average annual stroke risk of 4.5% per year. Despite warfarin reducing stroke risk by approximately 66%, prior studies show warfarin usage rates to be about 50%. However, the methods that define warfarin as "inappropriate underutilization" might not be sensitive enough to pick up relative contraindications. We assessed the inappropriate underutilization of warfarin in atrial fibrillation patients at our hospital by abstracting individual patient charts.

Methods

Medical records were reviewed to determine stroke risk factors, warfarin use, and documented contraindications to warfarin use in 364 consecutive patients with atrial fibrillation.

Results

Amongst 364 atrial fibrillation patients, 54.6% received warfarin anticoagulation. Overall, 29.5 % of patients had documented reasons for not prescribing warfarin. Primary reasons listed by treating physicians included: gastrointestinal bleed 10.7%, secondary/transient atrial fibrillation 8.2%, and fall risk 6.3%. Only 7.1% of the patients had no documented reasons for the lack of warfarin use.

Conclusion

Consistent with previous reports, 45.4% of patients in this atrial fibrillation cohort were not prescribed warfarin. However, after reviewing medical charts for documented reasons why warfarin was not used, the inappropriate underutilization rate was only 7.1%. These findings suggest that studies utilizing administrative database and ICD-9 CM coding might overestimate warfarin underutilization.

Application of a decision support tool for anticoagulation in patients with non-valvular atrial fibrillation

BACKGROUND

Atrial fibrillation affects more than two million Americans and results in a fivefold increased rate of embolic strokes. The efficacy of adjusted dose warfarin is well documented, yet many patients are not receiving treatment consistent with guidelines. The use of a patient-specific computerized decision support tool may aid in closing the knowledge gap regarding the best treatment for a patient.

METHODS

This retrospective, observational cohort analysis of 6,123 Ohio Medicaid patients used a patient-specific computerized decision support tool that automated the complex risk-benefit analysis for anticoagulation. Adverse outcomes included acute stroke, major gastrointestinal bleeding, and intracranial hemorrhage. Cox proportional hazards models were developed to compare the group of patients who received warfarin treatment with those who did not receive warfarin treatment, stratified by the decision support tool's recommendation.

RESULTS

Our decision support tool recommended warfarin for 3,008 patients (49%); however, only 9.9% received warfarin. In patients for whom anticoagulation was recommended by the decision support tool, there was a trend towards a decreased hazard for stroke with actual warfarin treatment (hazard ratio 0.90) without significant increase in gastrointestinal hemorrhage (0.87). In contrast, in patients for whom the tool recommended no anticoagulation, receipt of warfarin was associated with statistically significant increased hazard of gastrointestinal bleeding (1.54, p = 0.03).

CONCLUSIONS

We have shown that our atrial fibrillation decision support tool is a useful predictor of those at risk of major bleeding for whom anticoagulation may not necessarily be beneficial. It may aid in weighing the benefits versus risks of anticoagulation treatment.

Do physician outcome judgments and judgment biases contribute to inappropriate use of treatments? Study protocol

BACKGROUND

There are many examples of physicians using treatments inappropriately, despite clear evidence about the circumstances under which the benefits of such treatments outweigh their harms. When such over- or under- use of treatments occurs for common diseases, the burden to the healthcare system and risks to patients can be substantial. We propose that a major contributor to inappropriate treatment may be how clinicians judge the likelihood of important treatment outcomes, and how these judgments influence their treatment decisions. The current study will examine the role of judged outcome probabilities and other cognitive factors in the context of two clinical treatment decisions: 1) prescription of antibiotics for sore throat, where we hypothesize overestimation of benefit and underestimation of harm leads to over-prescription of antibiotics; and 2) initiation of anticoagulation for patients with atrial fibrillation (AF), where we hypothesize that underestimation of benefit and overestimation of harm leads to under-prescription of warfarin.

METHODS

For each of the two conditions, we will administer surveys of two types (Type 1 and Type 2) to different samples of Canadian physicians. The primary goal of the Type 1 survey is to assess physicians' perceived outcome probabilities (both good and bad outcomes) for the target treatment. Type 1 surveys will assess judged outcome probabilities in the context of a representative patient, and include questions about how physicians currently treat such cases, the recollection of rare or vivid outcomes, as well as practice and demographic details. The primary goal of the Type 2 surveys is to measure the specific factors that drive individual clinical judgments and treatment decisions, using a 'clinical judgment analysis' or 'lens modeling' approach. This survey will manipulate eight clinical variables across a series of sixteen realistic case vignettes. Based on the survey responses, we will be able to identify which variables have the greatest effect on physician judgments, and whether judgments are affected by inappropriate cues or incorrect weighting of appropriate cues. We will send antibiotics surveys to family physicians (300 per survey), and warfarin surveys to both family physicians and internal medicine specialists (300 per group per survey), for a total of 1,800 physicians. Each Type 1 survey will be two to four pages in length and take about fifteen minutes to complete, while each Type 2 survey will be eight to ten pages in length and take about thirty minutes to complete.

DISCUSSION

This work will provide insight into the extent to which clinicians' judgments about the likelihood of important treatment outcomes explain inappropriate treatment decisions. This work will also provide information necessary for the development of an individualized feedback tool designed to improve treatment decisions. The techniques developed here have the potential to be applicable to a wide range of clinical areas where inappropriate utilization stems from biased judgments.

Management of warfarin in atrial fibrillation: views of health professionals, older patients and their carers

OBJECTIVE

To identify the views of health professionals, patients and their carers on strategies to improve the use and management of warfarin in older patients with atrial fibrillation.

DESIGN

Qualitative study based on analysis of group interviews.

SETTING

A major metropolitan teaching hospital, from 1 March to 30 April 2003.

PARTICIPANTS

14 patients (>/= 65 years) with established atrial fibrillation and taking warfarin, three carers, 12 specialists, eight general practitioners, six community pharmacists, nine hospital pharmacists, and 11 nurses volunteered in response to flyers promoting the study.

RESULTS

Suggested strategies to improve warfarin management targeted support services for GPs and patients. Hospital-based clinicians felt that dissemination of trial evidence to GPs to support treatment recommendations is required, and that GPs need to enlist allied health professionals in the management of patients taking warfarin. GPs preferred access to practical advice from expert colleagues on the day-to-day management. Patients requested more information about warfarin therapy, as access to information is inadequate, particularly from primary sources (GPs, community pharmacists). Verbal and written information are equally important, but a single counselling session or supply of a booklet was viewed as inadequate. Participants identified various interventions for all levels of warfarin management; from the collective input, a framework for management strategies was developed.

CONCLUSIONS

Health professionals and patients require more customised information to support warfarin use and management.

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

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.

Atrial Fibrillation and Stroke in the General Medicare Population

BACKGROUND AND PURPOSE

Clinical trials have illustrated warfarin's protective effect on stroke risk in patients with atrial fibrillation (AF). The current study investigated temporal trends in AF prevalence, warfarin use, and its relation to stroke risk in Medicare patients with AF from 1992 to 2002.

METHODS

The Medicare 5% sample for 1992 to 2002 was used to create 1-year cohorts of patients with Medicare as primary payer throughout the year. International Classification of Diseases, Ninth Revision, Clinical Modification codes were used to identify AF, ischemic and hemorrhagic stroke, and comorbid conditions. A previously validated surrogate measure, prothrombin/international normalized ratio claims, was used to identify warfarin use. Cox proportional hazards regression was used to examine time to stroke with warfarin use as a time-dependent variable.

RESULTS

Among Medicare patients aged > or = 65 years, AF prevalence increased from 3.2% in 1992 to 6.0% in 2002 with higher prevalence in older subsets of the study population. Among patients with AF, warfarin use increased significantly (P< or = 0.001) for each year examined, from 24.5% in 1992 to 56.3% in 2002. Stroke rates per 1000 patient-years declined from 46.7 in 1992 to 19.5 in 2002 for ischemic stroke but remained fairly steady for hemorrhagic stroke (range, 1.6 to 2.9). Time-to-event modeling confirmed a protective association of warfarin against ischemic stroke among Medicare patients with AF.

CONCLUSIONS

This analysis represents an observational validation of stroke prevention in AF trials. The significant increase in warfarin use among patients with AF illustrates diffusion of trial evidence into clinical practice.