Warfarin prescribing in atrial fibrillation: the impact of physician, patient, and hospital characteristics

Prescription patterns of direct oral anticoagulants and concomitant use of interacting medications in the Netherlands

Objectives

To describe the prevalence, temporal and regional trends in prescribing direct oral anticoagulants (DOACs) in conjunction with interacting medications.

Methods

We performed a cross-sectional study of pharmacy dispensing data in the Foundation for Pharmaceutical Statistics (SFK) registry on patients who have had a prescription for a DOAC filled at one of 831 randomly selected pharmacies in the Netherlands between Jan 2014–Jan 2019.

Results

We identified 99,211 patients who had a first DOAC prescription filled. Mean age was 71.6 ± 10.9 years, 58% were male. In 2014, 8,293 patients were treated with DOACs, in 2018, 35,415 were newly started on a DOAC. In 2018, the use of apixaban was most common (52%) in the Eastern region, whereas rivaroxaban was most frequently prescribed (32–48%) in the other regions. At time of first prescription, the vast majority (99.3%) used ≥ 1 concomitant interacting drug, and 3.2% used ≥ 3 interacting medications. Most common were digoxin (37.8%), atorvastatin (31.5%), verapamil (13.7%) and amiodarone (9.7%). While the number of interacting medications remained unchanged over time (median 1, interquartile range 1–1), there was a notable decrease in antiarrhythmic medications and an increase in non-cardiovascular interacting medications (e.g. dexamethasone from 0.9% to 7.1%, antiepileptic drugs from 2.5% to 3.8%, and haloperidol from 0.5% to 2.2% in 2014 and 2018, respectively).

Conclusion

DOAC use has quadrupled in Dutch clinical practice over the 5‑year period from 2014 to 2018. While the number of patients who take interacting medications remained stable, the profile of interacting medications has changed over time from cardiovascular to medications affecting other organ systems.

Supplementary Information

The online version of this article (10.1007/s12471-021-01612-4) contains supplementary material, which is available to authorized users.

Restarting Oral Anticoagulation in Patients With Atrial Fibrillation After an Intracranial Hemorrhage

Atrial fibrillation is the most common sustained cardiac arrhythmia in the general population. In western countries with aging populations, atrial fibrillation poses a significant health concern, as it is associated with a high risk of thromboembolism, stroke, congestive heart failure, and myocardial infarction. Thrombi are generated in the left atrial appendage, and subsequent embolism into the cerebral circulation is a major cause of ischemic stroke. Therefore, patients have a lifetime risk of stroke, and those at high risk, defined as a CHA2DS2-VASc2 (congestive heart failure, hypertension, age >75 years, diabetes mellitus, stroke/transient ischemic attack/thromboembolism, vascular disease, age 65-74 yrs, sex category) ≥2, are usually placed on oral anticoagulants. Unfortunately, long-term anticoagulation poses bleeding risks, of which intracranial hemorrhage (ICH) is the most feared and deadly complication.In patients who survive an ICH, the question of oral anticoagulation resumption arises. It is a therapeutic dilemma in which clinicians must decide how to manage the risk of thromboembolism versus recurrent hemorrhage. Although there is a substantial amount of retrospective data on the topic of resumption of anticoagulation, there are, at this time, no randomized controlled trials addressing the issue. We therefore sought to address ICH risk and management, summarize high quality existing evidence on restarting oral anticoagulation, and suggest an approach to clinical decision-making.

Association of Healthcare Plan with atrial fibrillation prescription patterns

BACKGROUND

Atrial fibrillation (AF) is treated by many types of physician specialists, including primary care physicians (PCPs). Health plans have different policies for how patients encounter these providers, and these may affect selection of AF treatment strategy.

HYPOTHESIS

We hypothesized that healthcare plans with PCP-gatekeeping to specialist access may be associated with different pharmacologic treatments for AF.

METHODS

We performed a retrospective cohort study using a commercial pharmaceutical claims database. We utilized logistic regression models to compare odds of prescription of oral anticoagulant (OAC), non-vitamin K-dependent oral anticoagulant (NOAC), rate control, and rhythm control medications used to treat AF between patients with PCP-gated healthcare plans (eg, HMO, EPO, POS) and patients with non-PCP-gated healthcare plans (eg, PPO, CHDP, HDHP, comprehensive) between 2007 and 2012. We also calculated median time to receipt of therapy within 90 days of index AF diagnosis.

RESULTS

We found similar odds of OAC prescription at 90 days following new AF diagnosis in patients with PCP-gated plans compared to those with non-PCP-gated plans (OR: OAC 1.01, P = 0.84; warfarin 1.05, P = 0.08). Relative odds were similar for rate control (1.17, P < 0.01) and rhythm control agents (0.93, P = 0.03). However, PCP-gated plan patients had slightly lower likelihood of being prescribed NOACs (0.82, P = 0.001) than non-gated plan patients. Elapsed time until receipt of medication was similar between PCP-gated and non-gated groups across drug classes.

CONCLUSIONS

Pharmaceutical claims data do not suggest that PCP-gatekeeping by healthcare plans is a structural barrier to AF therapy, although it was associated with lower use of NOACs.

Thromboprophylaxis for Patients with High-risk Atrial Fibrillation and Flutter Discharged from the Emergency Department

Introduction

Many patients with atrial fibrillation or atrial flutter (AF/FL) who are high risk for ischemic stroke are not receiving evidence-based thromboprophylaxis. We examined anticoagulant prescribing within 30 days of receiving dysrhythmia care for non-valvular AF/FL in the emergency department (ED).

Methods

This prospective study included non-anticoagulated adults at high risk for ischemic stroke (ATRIA score ≥7) who received emergency AF/FL care and were discharged home from seven community EDs between May 2011 and August 2012. We characterized oral anticoagulant prescribing patterns and identified predictors of receiving anticoagulants within 30 days of the index ED visit. We also describe documented reasons for withholding anticoagulation.

Results

Of 312 eligible patients, 128 (41.0%) were prescribed anticoagulation at ED discharge or within 30 days. Independent predictors of anticoagulation included age (adjusted odds ratio [aOR] 0.89 per year, 95% confidence interval [CI] 0.82–0.96); ED cardiology consultation (aOR 1.89, 95% CI [1.10–3.23]); and failure of sinus restoration by time of ED discharge (aOR 2.65, 95% CI [1.35–5.21]). Reasons for withholding anticoagulation at ED discharge were documented in 139 of 227 cases (61.2%), the most common of which were deferring the shared decision-making process to the patient’s outpatient provider, perceived bleeding risk, patient refusal, and restoration of sinus rhythm.

Conclusion

Approximately 40% of non-anticoagulated AF/FL patients at high risk for stroke who presented for emergency dysrhythmia care were prescribed anticoagulation within 30 days. Physicians were less likely to anticoagulate older patients and those with ED sinus restoration. Opportunities exist to improve rates of thromboprophylaxis in this high-risk population.

Treatment of atrial fibrillation with warfarin among older adults with end stage renal disease

BACKGROUND

There is increasing evidence questioning the use of warfarin for atrial fibrillation (AF) among older adults with end stage renal disease (ESRD). We assessed the patterns and determinants of warfarin utilization among these patients in the US.

METHODS

We assembled a cohort of older adults (age ≥65) undergoing dialysis with incident AF from July 2007 to November 2011 from the US Renal Data System (USRDS). We used descriptive statistics to characterize warfarin utilization within 30 days of AF discharge, and logistic regression to quantify patient characteristics associated with warfarin initiation.

RESULTS

Among 5730 older adults undergoing dialysis with incident AF, 15.5% initiated warfarin. Among 2906 patients with high risk of bleeding, 12.7% initiated warfarin; whereas 14.9% initiated warfarin among 4824 patients with high risk of stroke. After adjustment for patient characteristics, warfarin initiation was lower among patients who were older [odds ratio (OR) = 0.74 per 10-year increase, 95% confidence interval (CI) 0.66-0.83] and those with a history of diabetes (OR = 0.75, 95% CI 0.63-0.90), myocardial infarction (OR = 0.64, 95% CI 0.50-0.80), or bleeding (OR = 0.63, 95% CI 0.50-0.80). There was no association between sex, race, or dialysis modality and warfarin initiation. Among patients who initiated warfarin, 46.8% discontinued warfarin use after a median treatment length of 8.6 months.

CONCLUSION

Despite the unclear benefit and increased bleeding risk of warfarin treatment in patients with ESRD, 1 in 8 older adults undergoing dialysis with incident AF in the US who had high risk of bleeding used warfarin. Changes to warfarin therapy due to discontinuation were common after initiation.

Trends in the prescription of novel oral anticoagulants in UK primary care

AIMS

Novel oral anticoagulants (NOACs) are alternatives to vitamin-K antagonists (VKAs) for the prevention of thromboembolism. It is unclear how NOACs have been adopted in the UK since first introduced in 2008. The present study was conducted to describe the trends in the prescription of NOACs in the UK, including dabigatran, rivaroxaban and apixaban.

METHODS

Using the UK's Clinical Practice Research Datalink, the rates of new use of NOACs and VKAs from 2009 to 2015 were calculated using Poisson regression. Patient characteristics associated with NOAC initiation were identified using multivariate logistic regression.

RESULTS

The overall rate of oral anticoagulant initiation increased by 58% over the study period [rate ratio (RR) 1.58; 95% confidence interval (CI) 1.23, 2.03], even as the rate of new VKA use decreased by 31% (RR 0.69; 95% CI 0.52, 0.93). By contrast, the rate of initiation of NOAC increased, particularly from 2012 onwards, with a 17-fold increase from 2012 to 2015 (RR 17.68; 95% CI 12.16, 25.71). In 2015, NOACs accounted for 56.5% of oral anticoagulant prescriptions, with rivaroxaban prescribed most frequently, followed by apixaban and then dabigatran. Compared to VKAs, new NOAC users were less likely to have congestive heart failure, coronary artery disease and peripheral vascular disease, and more likely to have a history of ischaemic stroke.

CONCLUSIONS

In the UK, the rate of initiation of NOACs has increased substantially since 2009, and these agents have now surpassed VKAs as the anticoagulant of choice. Moreover, the characteristics of patients initiated on NOACs have changed over time, and this should be accounted for in future studies comparing NOACs and VKAs.

Old and new oral anticoagulants: Food, herbal medicines and drug interactions

The most commonly prescribed oral anticoagulants worldwide are the vitamin K antagonists (VKAs) such as warfarin. Factors affecting the pharmacokinetics of VKAs are important because deviations from their narrow therapeutic window can result in bleedings due to over-anticoagulation or thrombosis because of under-anticoagulation. In addition to pharmacodynamic interactions (e.g., augmented bleeding risk for concomitant use of NSAIDs), interactions with drugs, foods, herbs, and over-the-counter medications may affect the risk/benefit ratio of VKAs. Direct oral anticoagulants (DOACs) including Factor Xa inhibitors (rivaroxaban, apixaban and edoxaban) and thrombin inhibitor (dabigatran) are poised to replace warfarin. Phase-3 studies and real-world evaluations have established that the safety profile of DOACs is superior to those of VKAs. However, some pharmacokinetic and pharmacodynamic interactions are expected. Herein we present a critical review of VKAs and DOACs with focus on their potential for interactions with drugs, foods, herbs and over-the-counter medications.

Warfarin treatment and risk of stroke among primary care patients with atrial fibrillation

OBJECTIVE

Our aim was to study the risk of a first ischaemic stroke (IS) in patients with atrial fibrillation (AF) treated in primary healthcare.

DESIGN

The study population included all adults (n = 11,517), 45 years and older diagnosed with AF, from 75 primary care centres in Sweden between 2001 and 2007. IS was defined as a hospital care event of stroke between 2001 and 2010. Association between incident stroke and warfarin treatment was explored using Cox regression analysis, with hazard ratios (HRs), and 95% confidence intervals (95%CIs). Adjustment was made for age, socioeconomic factors and co-morbidity.

RESULTS

Persistent treatment with warfarin was present among 33.7% of women and 40.0% among men. Persistent warfarin treatment, compared to no persistent treatment, was associated with a stroke preventing effect with fully adjusted HRs of 0.25 (95%CI 0.18-0.36) in women, and 0.25 (95%CI 0.19-0.32) in men. A CHA₂DS₂-VASc score of at least two among women, and three among men, was associated with a stroke risk exceeding 18% during a mean follow-up of 5.4 years. Risk of haemorrhagic stroke was not increased.

CONCLUSIONS

Warfarin is effective in preventing stroke in AF patients in primary healthcare.

The Influence of Socioeconomic Status on Selection of Anticoagulation for Atrial Fibrillation

IMPORTANCE

Without third-party insurance, access to marketed drugs is limited to those who can afford to pay. We examined this phenomenon in the context of anticoagulation for patients with nonvalvular atrial fibrillation (NVAF).

OBJECTIVE

To determine whether, among older Ontarians receiving anticoagulation for NVAF, patients of higher socioeconomic status (SES) were more likely to switch from warfarin to dabigatran prior to its addition to the provincial formulary.

DESIGN, SETTING AND PARTICIPANTS

Population-based retrospective cohort study of Ontarians aged 66 years and older, between 2008 and 2012.

EXPOSURE

Socioeconomic status, as approximated by median neighborhood income.

MAIN OUTCOMES AND MEASURE

We identified two groups of older adults with nonvalvular atrial fibrillation: those who appeared to switch from warfarin to dabigatran after its market approval but prior to its inclusion on the provincial formulary ("switchers"), and those with ongoing warfarin use during the same interval ("non-switchers").

RESULTS

We studied 34,797 patients, including 3183 "switchers" and 31,614 "non-switchers". We found that higher SES was associated with switching to dabigatran prior to its coverage on the provincial formulary (p<0.0001). In multivariable analysis, subjects in the highest quintile were 50% more likely to switch to dabigatran than those in the lowest income quintile (11.3% vs. 7.3%; adjusted odds ratio 1.50; 95% CI 1.32 to 1.68). Following dabigatran's addition to the formulary, the income gradient disappeared.

CONCLUSIONS AND RELEVANCE

We documented socioeconomic inequality in access to dabigatran among patients receiving warfarin for NVAF. This disparity was eliminated following the drug's addition to the provincial formulary, highlighting the importance of timely reimbursement decisions.

Gastrointestinal bleeding in patients receiving oral anticoagulation: Current treatment and pharmacological perspectives

Gastrointestinal bleeding (GIB) is a potentially fatal and avoidable medical condition that poses a burden on global health care costs. The rate of major GIB related to the use of some direct acting oral anticoagulant drugs (DOACs), is higher than that detected in warfarin users. Current strategies in the treatment of GIBs in patients receiving warfarin or DOACs (vitamin K, activated charcoal; hemodialysis; recombinant factor VIIa; [activated] prothrombin complex concentrates) including indications for the treatment of bleeding based on different degrees of severity of the episodes, is reported in this article. Potential preventive strategies to mitigate the risk of GIBs (e.g. upper endoscopy/biopsy, colon cancer screening; eradication of Helicobacter pylori prior to starting anticoagulation; use of proton-pump inhibitors, identification of risk factors for bleeding) are also reported as well as the fact that some of them have not been tested so far in patients receiving DOACs. Antidotes that experimentally reverse the anti-coagulant effect of dabigatran (Idarucizumab; BI 655075; Boehringer Ingelheim); of rivaroxaban, apixaban, or edoxaban (Andexanet alfa, r-Antidote, PRT064445; Portola Pharmaceuticals) or of all DOACs (Aripazine, PER-977, ciraparantag; Perosphere Inc.) are discussed. Likewise, population pharmacokinetics modeling related to the rate of major DOACs-related GIBs is presented. It is also emphasized that the occurrence of GIB reflects the presence of patients at the highest risk for adverse outcomes. Finally, the implications of the concept that patient characteristics and the severity of illness (i.e. comorbidities) exert a greater impact on the risk of GIB than the type of antithrombotic agent employed, are analyzed.

Neighborhood deprivation and warfarin, aspirin and statin prescription - A cohort study of men and women treated for atrial fibrillation in Swedish primary care

BACKGROUND

We aimed to study differences in the prescribing of warfarin, aspirin and statins to patients with atrial fibrillation (AF) in socio-economically diverse neighborhoods. We also aimed to explore the effects of neighborhood deprivation on the relationship between CHADS2 risk score and warfarin prescription.

METHODS

Data were obtained from primary health care records that contained individual clinical data that were linked to national data on neighborhood of residence and a deprivation index for different neighborhoods. Logistic regression was used to estimate the potential neighborhood differences in prescribed warfarin, aspirin and statins, and the association between the CHADS2 score and prescribed warfarin treatment, in neighborhoods with high, middle (referent) and low socio-economic (SES).

RESULTS

After adjustment for age, socio-economic factors, co-morbidities and moves to neighborhoods with different SES during follow-up, adults with AF living in high SES neighborhoods were more often prescribed warfarin (men odds ratio (OR) (95% confidence interval (CI): 1.44 (1.27-1.62); and women OR (95% CI): 1.19 (1.05-1.36)) and statins (men OR (95% CI): 1.23 (1.07-1.41); women OR (95% CI): 1.23 (1.05-1.44)) compared to their counterparts residing in middle SES. Prescription of aspirin was lower in men from high SES neighborhoods (OR (95% CI): 0.75 (0.65-0.86)) than in those from middle SES neighborhoods. Higher CHADS2 risk scores were associated with higher warfarin prescription which remained after adjustment for neighborhood SES.

CONCLUSIONS

The apparent inequalities in pharmacotherapy seen in the present study call for resource allocation to primary care in neighborhoods with low and middle socio-economic status.

Antithrombotic drugs, patient characteristics, and gastrointestinal bleeding: Clinical translation and areas of research

Gastrointestinal bleeding (GIB) is a potentially fatal and avoidable medical condition that poses a burden on global health care costs. Current understanding of the roles of platelet activation and thrombin generation/activity in vascular medicine has led to the development of effective antithrombotic treatments. However, in parallel with a sustained coronary and cerebral flow patency, the increasingly intensive treatment with warfarin; direct oral anticoagulant drugs [DOACs], and/or with aspirin ± clopidogrel (or ± prasugrel or ± ticagrelor), has increased the burden of GIBs related to the use of antithrombotic agents. Compelling evidence concerning this issue is accumulating to indicate that: 1) the risk of GIB related to the use of antithrombotic drugs dramatically differs in different clinical settings; and 2) the characteristics of patients (e.g., severity of illness, comorbidities) in whom it is used exert a greater impact on the risk of GIB than the type of antithrombotic agent employed. The latter concept argues for the occurrence of GIB as reflecting the presence of patients at the highest risk for adverse outcomes. The HAS-BLED score identifies subjects at risk of bleeding among those untreated and those treated with warfarin, DOACs and/or low-dose aspirin. Its use within the frame of a severity score (e.g., the CHA2DS2-VASc score in patients with atrial fibrillation) helps balance the benefits and the risks of an antithrombotic treatment and identify those patients in whom the absolute gain (vascular events prevented) outweighs the risk of GIB. Potential implications of the latter information in settings other than atrial fibrillation is thoroughly discussed.

Can physicians identify inappropriate nuclear stress tests? An examination of inter-rater reliability for the 2009 appropriate use criteria for radionuclide imaging

BACKGROUND

We sought to determine inter-rater reliability of the 2009 Appropriate Use Criteria for radionuclide imaging and whether physicians at various levels of training can effectively identify nuclear stress tests with inappropriate indications.

METHODS AND RESULTS

Four hundred patients were randomly selected from a consecutive cohort of patients undergoing nuclear stress testing at an academic medical center. Raters with different levels of training (including cardiology attending physicians, cardiology fellows, internal medicine hospitalists, and internal medicine interns) classified individual nuclear stress tests using the 2009 Appropriate Use Criteria. Consensus classification by 2 cardiologists was considered the operational gold standard, and sensitivity and specificity of individual raters for identifying inappropriate tests were calculated. Inter-rater reliability of the Appropriate Use Criteria was assessed using Cohen κ statistics for pairs of different raters. The mean age of patients was 61.5 years; 214 (54%) were female. The cardiologists rated 256 (64%) of 400 nuclear stress tests as appropriate, 68 (18%) as uncertain, 55 (14%) as inappropriate; 21 (5%) tests were unable to be classified. Inter-rater reliability for noncardiologist raters was modest (unweighted Cohen κ, 0.51, 95% confidence interval, 0.45-0.55). Sensitivity of individual raters for identifying inappropriate tests ranged from 47% to 82%, while specificity ranged from 85% to 97%.

CONCLUSIONS

Inter-rater reliability for the 2009 Appropriate Use Criteria for radionuclide imaging is modest, and there is considerable variation in the ability of raters at different levels of training to identify inappropriate tests.

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.

Pharmacotherapy for atrial fibrillation in elderly hospitalized patients with comorbid congestive heart failure in australia: A retrospective study

BACKGROUND

Despite the proven effectiveness of antiplatelet and anticoagulation treatment for atrial fibrillation (AF), their use has been suboptimal in practice, particularly in rural areas of Australia.

OBJECTIVE

The aim of this study was to describe medication use in the management of AF in elderly hospitalized patients with comorbid congestive heart failure (CHF).

METHODS

The hospital records of patients with a diagnosis of AF and CHF were reviewed in a rural Australian medical center. All the patients were hospitalized because of significant systolic ventricular dysfunction. The collected data included age, sex, weight, presenting symptoms of AF, and principle diagnosis on admission; medical history; and history of smoking and alcohol consumption. Electrocardiogram before hospital discharge was also retrieved from patient's medical records and was analyzed by the investigators. Cardiovascular and noncardiovascular drugs administered during the hospital stay and at discharge were also documented. Comparison of antiarrhythmic and anticoagulant drugs was made between patients who had AF while hospitalized and those who had a history of AF but were in sinus rhythm while hospitalized. When patients had ≥2 moderate risk factors (eg, age ≥75 years, hypertension, CHF, left ventricular ejection fraction ≤35%, diabetes mellitus) or ≥1 high risk factor (eg, previous stroke, transient ischemic attack or embolism, mitral valve stenosis, or prosthetic heart valve), they were defined as being eligible for anticoagulation treatment.

RESULTS

One hundred forty patients (74 men, 66 women; mean [SD] age, 77.1 [6.9] years; all were white) had a diagnosis of AF and were selected for the study. Of these, 92 patients (65.7%) (47 women, 45 men; mean [SD] age, 77.4 [9-2] years) had continuous AF and 48 patients (34.3%) (29 men, 19 women; mean [SD] age, 76.3 [12.4] years) had a history of AF but were in sinus rhythm at admission and discharge. The most commonly used antiarrhythmic drug was digoxin, which was prescribed significantly more frequently in the AF group than in the history of AF group (50 (54.3%] vs 14 [29.2%]; P < 0.01). Amiodarone was prescribed significantly less frequently in the continuous AF group than in the group with a history of AF (7 [7.6%] vs 19 [39-6%]; P < 0.01). There was no significant between-group difference in the use of β-blockers (26 [28.3%] vs 19 [39-6%]), verapamil/diltiazem (9 [9-8%] vs 3 [6.3%]), or Sotalol (2 [2.2%] vs 4 [8.3%]). The mean (SD) resting heart rate for the 140 study patients was 91 (27) bpm. The mean resting heart rate for the patients with AF was significantly higher at admission than at discharge (97 [28] vs 79 [19] bpm; P < 0.01). Of the 110 patients who were eligible for anticoagulation treatment, 64 (58.2%) were prescribed warfarin at discharge. Eligible patients not receiving oral warfarin were significantly older than those who did receive warfarin (79-7 [9-0] vs 75.8 [9.0] years; P = 0.02).

CONCLUSIONS

In these elderly hospitalized Australian patients with AF and CHF, digoxin, β-blockers, and amiodarone were the most commonly used antiarrhythmic drugs. Anticoagulation treatment was prescribed in ~60% of these patients.

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.

Rationale and design of the Left Atrial Appendage Occlusion Study (LAAOS) III

BACKGROUND

Occlusion of the left atrial appendage (LAA) is a promising approach to stroke prevention in atrial fibrillation (AF). However, evidence of its efficacy and safety to date is lacking. We herein describe the rationale and design of a definitive LAA occlusion trial in cardiac surgical patients with AF.

METHODS

We plan to randomize 4,700 patients with AF in whom on-pump cardiac surgical procedure is planned to undergo LAA occlusion or no LAA occlusion. The primary outcome is the first occurrence of stroke or systemic arterial embolism over a mean follow-up of four years. Other outcomes include total mortality, operative safety outcomes (chest tube output in the first post-operative 24 hours, rate of post-operative re-exploration for bleeding in the first 48 hours post-surgery and 30-day mortality), re-hospitalization for heart failure, major bleed, and myocardial infarction.

RESULTS

Left Atrial Appendage Occlusion Study (LAAOS) III is funded in a vanguard phase by the Canadian Institutes for Health Research (CIHR), the Canadian Network and Centre for Trials Internationally, and the McMaster University Surgical Associates. As of September 9, 2013, 162 patients have been recruited into the study.

CONCLUSIONS

LAAOS III will be the largest trial to explore the efficacy of LAA occlusion for stroke prevention. Its results will lead to a better understanding of stroke in AF and the safety and efficacy of surgical LAA occlusion.

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.

[The management of atrial fibrillation and characteristics of its current care in outpatients. AFABE observational study]

AIM

To provide insights into the characteristics and management of outpatients when their atrial fibrillation (AF) was first detected: diagnosis, treatment and follow-up in the context of the public health system.

DESIGN

AFABE is an observational, multicentre descriptive study with retrospective data collection relating to the practice patterns, management and initial strategies of treatment of patients with diagnosed AF in the context of primary care, emergency and cardiologists of the public health system.

SETTING

Primary and Specialist care. Baix Ebre region. Tarragona. Spain.

SUBJECTS

A representative sample of 182 subjects > 60-year-old with AF who have been randomized, recruited among the registered patients with AF in 22 primary care centres in the area of the study.

MESUREMENTS

Demographic data, comorbidities (AF), CHA2DS2-VASc and HAS_BLED scores, and practice patterns results between Primary Care and referral services.

RESULTS

A total of 182 patients were included (mean age 78.5 SD:7.3 years; 50% women). Most patients (68.3% 95%CI; 60.3-76.3) had the first contact in Primary Care, of which 56.3% (95%CI; 45.2-66.0) were sent to Hospital Emergency Department where 72.7% (95%CI: 63.5-79.0) of the oral anticoagulation and 58.4% (95%CI: 49.4-66.9) of antiarrhytmic treatments were started. More than half (55.9%:95%CI; 47.2-64.7, of patients with permanent AF were followed-up by the Cardiology department.

CONCLUSIONS

Most patients with newly diagnosed AF made a first contact with Primary Care, but around half were sent to Hospital Emergency departments, where they were treated with an antiarrhythmic and/or oral anticoagulation.

Limited English proficient patients and time spent in therapeutic range in a warfarin anticoagulation clinic

Background

While anticoagulation clinics have been shown to deliver tailored, high‐quality care to patients receiving warfarin therapy, communication barriers with limited English proficient (LEP) patients may lead to disparities in anticoagulation outcomes.

Methods and Results

We analyzed data on 3770 patients receiving care from the Massachusetts General Hospital Anticoagulation Management Service (AMS) from 2009 to 2010. This included data on international normalized ratio (INR) tests and patient characteristics, including language and whether AMS used a surrogate for primary communication. We calculated percent time in therapeutic range (TTR for INR between 2.0 and 3.0) and time in danger range (TDR for INR <1.8 or >3.5) using the standard Rosendaal interpolation method. There were 241 LEP patients; LEP patients, compared with non‐LEP patients, had a higher number of comorbidities (3.2 versus 2.9 comorbidities, P=0.004), were more frequently uninsured (17.0% versus 4.3%, P<0.001), and less educated (47.7% versus 6.0% ≤high school education, P<0.001). LEP patients compared with non‐LEP patients spent less TTR (71.6% versus 74.0%, P=0.007) and more TDR (12.9% versus 11.3%, P=0.018). In adjusted analyses, LEP patients had lower TTR as compared with non‐LEP patients (OR 1.5, 95% CI [1.1, 2.2]). LEP patients who used a communication surrogate spent less TTR and more TDR.

Conclusion

Even within a large anticoagulation clinic with a high average TTR, a small but significant decrease in TTR was observed for LEP patients compared with English speakers. Future studies are warranted to explore how the use of professional interpreters impact TTR for LEP patients.

Trends in the incidence of atrial fibrillation in older patients initiating dialysis in the United States

BACKGROUND

One sixth of US dialysis patients 65 years of age have been diagnosed with atrial fibrillation/flutter (AF). Little is known, however, about the incidence of AF in this population.

METHODS AND RESULTS

We identified 258 605 older patients (≥67 years of age) with fee-for-service Medicare initiating dialysis in 1995 to 2007, who had not been diagnosed with AF within the previous 2 years. Patients were followed for newly diagnosed AF. Multivariable proportional hazard regression was used to examine temporal trends and associations of race and ethnicity with incident AF. We also studied temporal trends in the mortality and risk of ischemic stroke after new AF. Over 514 395 person-years of follow-up, 76 252 patients experienced incident AF for a crude AF incidence rate of 148/1000 person-years. Incidence of AF increased by 11% (95% confidence interval, 5-16) from 1995 to 2007. Compared with non-Hispanic whites, blacks (-30%), Asians (-19%), Native Americans (-42%), and Hispanics (-29%) all had lower rates of incident AF. Mortality after incident AF decreased by 22% from 1995 to 2008. Even more pronounced reductions were seen for incident ischemic stroke during these years.

CONCLUSIONS

The incidence of AF is high in older patients initiating dialysis in the United States and has been increasing over the 13 years of study. Mortality declined during that time but remained >50% during the first year after newly diagnosed AF. Because data on warfarin use were not available, we were unable to study whether trends toward better outcomes could be explained by higher rates of oral anticoagulation.

Prevalence of atrial fibrillation and warfarin use in older patients receiving hemodialysis

BACKGROUND

Little is known about the use of warfarin in hemodialysis (HD) patients with atrial fibrillation (AF). We studied temporal trends of AF among older HD patients, and of warfarin use among those with AF.

METHODS

We linked US Medicare and prescription claims from older patients undergoing HD in 2 Eastern US states. We established annual cohorts of prevalent HD patients; AF was ascertained from >2 claims (>7 days apart) in the same year, with a diagnosis code indicating AF. Among those with AF, we defined current and past warfarin use. Demographic and clinical characteristics were also ascertained for each cohort. We used repeated-measures logistic regression to define the odds of AF and of current or past versus absence of warfarin use.

RESULTS

Of 6,563 unique patients, 2,185 were determined to have AF. The prevalence of AF increased from 26% in 1998 to 32% in 2005. In 2005, current warfarin use was present in 24% of AF patients and past use in 25%; 51% had no evidence of any warfarin use. No significant trends in utilization were observed from 1998 through 2005. Patients aged =85 years and nonwhites were less likely to have received warfarin; most comorbidities were not associated with warfarin use except for patients with past pulmonary embolism or deep venous thrombosis who were more likely than those without such history.

CONCLUSION

While the prevalence of AF has been increasing among older HD patients, warfarin use was low and unchanged over time, perhaps reflecting the lack of evidence supporting its use.

Supporting Treatment decision making to Optimise the Prevention of STROKE in Atrial Fibrillation: the STOP STROKE in AF study. Protocol for a cluster randomised controlled trial

BACKGROUND

Suboptimal uptake of anticoagulation for stroke prevention in atrial fibrillation has persisted for over 20 years, despite high-level evidence demonstrating its effectiveness in reducing the risk of fatal and disabling stroke.

METHODS

The STOP STROKE in AF study is a national, cluster randomised controlled trial designed to improve the uptake of anticoagulation in primary care. General practitioners from around Australia enrolling in this 'distance education' program are mailed written educational materials, followed by an academic detailing session delivered via telephone by a medical peer, during which participants discuss patient de-identified cases. General practitioners are then randomised to receive written specialist feedback about the patient de-identified cases either before or after completing a three-month posttest audit. Specialist feedback is designed to provide participants with support and confidence to prescribe anticoagulation. The primary outcome is the proportion of patients with atrial fibrillation receiving oral anticoagulation at the time of the posttest audit.

DISCUSSION

The STOP STROKE in AF study aims to evaluate a feasible intervention via distance education to prevent avoidable stroke due to atrial fibrillation. It provides a systematic test of augmenting academic detailing with expert feedback about patient management.

Safety and effectiveness of antithrombotic strategies in older adult patients with atrial fibrillation and non-ST elevation myocardial infarction

BACKGROUND

We aimed to study the comparative safety and effectiveness of various antithrombotic treatment strategies among older adults with non-ST elevation myocardial infarction (NSTEMI) and atrial fibrillation (AF).

METHODS

Using the CRUSADE registry linked to longitudinal Medicare claims data, we examined NSTEMI patients aged ≥ 65 years with a concomitant diagnosis of AF. Multivariable Cox analysis was used to compare risk of rehospitalization for bleeding and a major cardiac composite end point of death, readmission for myocardial infarction, or stroke, according to discharge antithrombotic strategy.

RESULTS

Among 7619 NSTEMI patients with AF, 29% were discharged on aspirin alone; 37%, on aspirin + clopidogrel; 7%, on warfarin alone; 17%, on aspirin + warfarin; and 10%, on warfarin + aspirin + clopidogrel. There was no difference in predicted stroke risk between groups. By 1 year, 12.2% of patients were rehospitalized for bleeding, and 33.1% had a major cardiac event. Relative to aspirin alone, antithrombotic intensification was associated with increased bleeding risk (aspirin + clopidogrel adjusted HR 1.22, 95% CI 1.03-1.46 and warfarin + aspirin HR 1.46, 95% CI 1.21-1.80). Patients treated with aspirin + clopidogrel + warfarin had the highest observed bleeding risk (HR 1.65, 95% CI 1.30-2.10). One-year risk of the major cardiac end point was similar between groups, although, relative to aspirin only, there was a trend toward lower risk for the warfarin + aspirin group (HR 0.88, 95% CI 0.78-1.00).

CONCLUSIONS

Older NSTEMI patients with AF are at high risk for subsequent bleeding and major cardiac events. Increased antithrombotic management was associated with increased bleeding risk. Further investigation is needed to clarify whether these risks are counterbalanced by reduced thromboembolic events in this population.

Development of a Computerised Antithrombotic Risk Assessment Tool (CARAT) to optimise therapy in older persons with atrial fibrillation

AIM

To develop and evaluate a novel Computerised Antithrombotic Risk Assessment Tool (CARAT) to aid clinicians' decision making regarding the risk-benefit of antithrombotic therapy in older patients.

METHODS

CARAT was developed in an iterative process involving multidisciplinary feedback and computerisation of previously trialled algorithms. Hospital-based clinicians then applied the tool to patient cases, to evaluate its usability.

RESULTS

Overall, 94% of clinicians (n= 27 yielding 216 responses) were satisfied with CARAT's format. Most (72%) clinician responses agreed with CARAT recommendations; over two-thirds agreed with estimates of stroke and bleeding risk. However, geriatricians were 3.5 times more likely to disagree with CARAT recommendations than cardiologists, particularly in cases of high fall risk. Overall, 63% responded that CARAT was at least 'somewhat useful' for clinical practice; 22% indicating it was 'very useful'.

CONCLUSION

CARAT has potential as a useful decision-support tool to assist clinicians in decision making regarding appropriate antithrombotic therapy in older patients.

Association of echocardiography before major elective non-cardiac surgery with postoperative survival and length of hospital stay: population based cohort study

OBJECTIVE

To determine the association of resting echocardiography before elective intermediate to high risk non-cardiac surgery with survival and length of hospital stay.

DESIGN

Population based retrospective cohort study.

SETTING

Acute care hospitals in Ontario, Canada, between 1 April 1999 and 31 March 2008.

PARTICIPANTS

Patients aged over 40 years who had elective intermediate to high risk non-cardiac surgery.

INTERVENTION

Resting echocardiography within 6 months before surgery.

MAIN OUTCOME MEASURES

Postoperative survival (30 days and 1 year) and length of hospital stay; postoperative surgical site infection as an outcome for which no association with echocardiography would be expected.

RESULTS

Of the 264,823 patients in the entire cohort, 15.1% (n = 40,084) had echocardiography. After use of propensity score methods to assemble a matched cohort (n = 70,996) that reduced differences between patients who had or had not had echocardiography, echocardiography was associated with increases in 30 day mortality (relative risk 1.14, 95% confidence interval 1.02 to 1.27), 1 year mortality (1.07, 1.01 to 1.12), and length of hospital stay but no difference in surgical site infections (1.03, 0.98 to 1.06). The association with mortality was influenced (P = 0.02) by whether patients had had stress testing or had risk factors for cardiac complications. No association existed between echocardiography and mortality among patients who had stress testing (relative risk 1.01, 0.92 to 1.11) or among patients at high risk who had not had stress testing (1.00, 0.87 to 1.13). However, echocardiography was associated with mortality in patients at low risk (relative risk 1.44, 1.14 to 1.82) and intermediate risk (1.10, 1.02 to 1.18) who had not had stress testing.

CONCLUSIONS

Preoperative echocardiography was not associated with improved survival or shorter hospital stay after major non-cardiac surgery. These findings highlight the need for further research to guide better use of this common preoperative test.

Should anticoagulation be resumed after intracerebral hemorrhage?

Intracerebral hemorrhage (ICH) is the most feared and the most deadly complication of oral anticoagulant therapy, eg, with warfarin (Coumadin). After such an event, clinicians wonder whether their patients should resume anticoagulant therapy. The authors review the management of anticoagulation during and after anticoagulation-associated ICH.

Study protocol: the DESPATCH study: delivering stroke prevention for patients with atrial fibrillation - a cluster randomised controlled trial in primary healthcare

Background

Compelling evidence shows that appropriate use of anticoagulation in patients with nonvalvular atrial fibrillation reduces the risk of ischaemic stroke by 67% and all-cause mortality by 26%. Despite this evidence, anticoagulation is substantially underused, resulting in avoidable fatal and disabling strokes.

Methods

DESPATCH is a cluster randomised controlled trial with concealed allocation and blinded outcome assessment designed to evaluate a multifaceted and tailored implementation strategy for improving the uptake of anticoagulation in primary care. We have recruited general practices in South Western Sydney, Australia, and randomly allocated practices to receive the DESPATCH intervention or evidence-based guidelines (control). The intervention comprises specialist decisional support via written feedback about patient-specific cases, three academic detailing sessions (delivered via telephone), practice resources, and evidence-based information. Data for outcome assessment will be obtained from a blinded, independent medical record audit. Our primary endpoint is the proportion of nonvalvular atrial fibrillation patients, over 65 years of age, receiving oral anticoagulation at any time during the 12-month posttest period.

Discussion

Successful translation of evidence into clinical practice can reduce avoidable stroke, death, and disability due to nonvalvular atrial fibrillation. If successful, DESPATCH will inform public policy, providing quality evidence for an effective implementation strategy to improve management of nonvalvular atrial fibrillation, to close an important evidence-practice gap.

Trial registration

Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12608000074392

Variation in initiating secondary prevention after myocardial infarction by hospitals and physicians, 1997 through 2004

PURPOSE

Myocardial infarction (MI) survivors benefit from receiving secondary prevention, including beta-blockers, angiotensin-blocking agents, and statins, as recommended by guidelines. Compliance with these guidelines is suboptimal. We sought to describe the initiation of secondary prevention in MI survivors, and to describe the variation in initiation by discharging the hospital, the physician, and the physician "responsible" for secondary prevention prescribing decisions in British Columbia in 1997-2004.

METHODS

We assembled a cohort of 28,613 patients discharged alive from the hospital after their first MI and were not readmitted within 30 days. Physicians responsible for prescribing post-MI secondary prevention medications were identified as the physicians prescribing the greatest number of cardiac medications (post-discharge cardiac prescribers). We used multilevel logistic regression to assess the variation in drug initiation at discharging hospital, discharging physician, and post-discharge cardiac prescriber levels, which were adjusted for patient and provider characteristics during the study period.

RESULTS

Beta-blockers initiation increased from 56 to 71% over the 8-year study period; angiotensin-converting enzyme/angiotensin II receptor blocker initiation increased from 37 to 70%, and statin initiation increased from 22 to 66% (0-28% for high-potency statins). The probability for initiating an average patient with the study drugs varied widely in age-sex-adjusted models at the hospital and physician levels. Further adjustment did not meaningfully change findings. The variation was largest for statins. The maximum between-provider variance was found for high-potency statins in 2003-2004 at the post-discharge cardiac prescriber level.

CONCLUSIONS

Study-drug initiation is increasing among MI survivors, but the variation in initiation is wide between discharging hospitals and physicians.

The increasing prevalence of atrial fibrillation among hemodialysis patients

A half million Americans have ESRD, which puts them at high risk for cardiovascular disease and poor outcomes. Little is known about the epidemiology of atrial fibrillation among patients with ESRD. We analyzed data from annual cohorts (1992 to 2006) of prevalent hemodialysis patients from the United States Renal Data System. In each cohort, we searched 1 year of medical claims for relevant diagnosis codes to determine the prevalence of atrial fibrillation. Among 2.5 million patient observations, 7.7% had atrial fibrillation, with the prevalence increasing 3-fold from 3.5% (1992) to 10.7% (2006). The number of affected patients increased from 3620 to 23,893 (6.6-fold) during this period. Older age, male gender, and several comorbid conditions were associated with increased risk for atrial fibrillation. Compared with otherwise similar Caucasians, the prevalence of atrial fibrillation rates was substantially lower for blacks, Asians, and Native Americans. One-year mortality was twice as high among hemodialysis patients with atrial fibrillation compared with those without (39% versus 19%), and this increased risk was constant during the 15 years of the study. In conclusion, the prevalence of diagnosed atrial fibrillation among patients receiving hemodialysis in the United States is increasing, varies by race, and remains associated with substantially increased mortality. Identifying potentially modifiable risk factors for incident atrial fibrillation requires further investigation.

Patient and physician predictors of peritoneal dialysis technique failure: a population based, retrospective cohort study

BACKGROUND

The use of peritoneal dialysis (PD) has been declining over the past decade in Canada, and high technique failure rates have been implicated. Studies have examined clinical risk factors for PD technique failure, but few studies have addressed sociodemographic factors driving technique failure. There are no studies examining the effect of physician factors on technique failure.

METHODS

We conducted a retrospective cohort study using Ontario healthcare databases from 1 April 1995 to 31 March 2005 to examine the effects of patient sociodemographic and physician characteristics on PD technique failure. The primary outcome was time to technique failure. Secondary outcomes included the proportion of patients experiencing technique failure during the first year and the proportion of patients experiencing death during the study period. A competing risks analysis was applied to the Cox proportional hazards model to determine the predictors of technique failure, death, and kidney transplantation.

RESULTS

In 5162 incident PD patients, the probability of technique success and patient survival at 5 years was 58.2% and 46.9% respectively. Of patients failing PD, 43.5% failed during the first year of treatment. Statistically significant predictors of technique failure included increasing age [hazard ratio (HR) 1.02], diabetes mellitus (HR 1.32), lower neighborhood education level (HR 2.93), and receiving transient (≤ 3 months) hemodialysis before starting PD (HR 1.24). Predictors of patient death included increasing age (HR 1.05), diabetes mellitus (HR 1.44), coronary artery disease (HR 1.26), congestive heart failure (HR 1.58), and late referral to the nephrologist (HR 1.27). Distance from treating dialysis center and residing in a rural area did not impact the risk of technique failure or death. Male physician gender increased the risk of technique failure (HR 1.31). Increased PD patient volume decreased the risk of technique failure (HR 0.98). None of the physician factors were predictors of patient death.

CONCLUSION

These findings support the need for implementing strategies to reduce technique failure, which could include increasing educational resources for patients initiating PD, aggressive risk factor modification in patients with multiple comorbidities, and increasing physician awareness regarding the detrimental outcomes associated with late referral and late PD start.

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.

Clinical consequences of hospital variation in use of oral anticoagulant therapy after first-time admission for atrial fibrillation

OBJECTIVE

To analyse how hospital factors influence the use of oral anticoagulants (OAC) in atrial fibrillation (AF) patients and address the clinical consequences of hospital variation in OAC use.

DESIGN AND SUBJECTS

By linkage of nationwide Danish administrative registers we conducted an observational study including all patients with a first-time hospitalization for AF between 1995 and 2004 as well as prescription claims for OAC. Multivariable logistic regression analysis was used to evaluate hospital factors associated with prescription of OAC therapy. Cox proportional-hazard models were used to estimate the risk of re-hospitalization for thromboembolism and haemorrhagic stroke with respect to discharge from a low, intermediate, or high OAC use hospital.

RESULTS

Overall 40,133 (37%) out of 108,504 patients received OAC; ranging from 17% to 50% between the hospitals with the lowest and highest OAC use, respectively. Cardiology departments had the highest use of OAC, but neither tertiary university hospitals nor high volume hospitals had higher OAC use than local community hospitals and low volume hospitals. Risk of a thromboembolic event was significantly increased amongst patients from hospitals with a low OAC use (hazard ratio 1.16, confidence interval 1.10-1.22). Notably, higher OAC use was not associated with a higher risk of haemorrhagic stroke.

CONCLUSION

In Denmark between 1995 and 2004, there was a major hospital variation in AF patients receiving OAC, and consequently, more thromboembolic events were observed amongst patients from low OAC use hospitals. Our study emphasizes the need for a continued vigilance on implementation of international AF management guidelines.

The effect of Medicare Part D coverage on drug use and cost sharing among seniors without prior drug benefits

This study evaluates the effect of Medicare Part D among seniors who previously lacked drug coverage, using time-trend analyses of patient-level dispensing data from three pharmacy chains. Of 114,766 seniors without drug benefits, 55 percent initiated drug insurance under Part D. After the penalty-free Part D enrollment period, use of statins, clopidogrel, and proton pump inhibitors stabilized at levels ranging from 11 percent to 37 percent above the trend that would have been expected if Part D had not been implemented. Patients reaching the Part D coverage gap (12 percent) experienced a decrease in essential medication use ranging from 5.7 percentage points per month for warfarin to 6.3 percentage points for statins.

Differential use of warfarin for secondary stroke prevention in patients with various types of atrial fibrillation

Anticoagulation therapy significantly reduces the incidence of thromboembolic events in patients with atrial fibrillation (AF), and warfarin therapy at discharge is a class I-indicated drug in patients with ischemic stroke with persistent or paroxysmal AF without contraindications. The aim was to determine whether participation in the Get With The Guidelines-Stroke (GWTG-S) quality improvement program would be associated with improved adherence to anticoagulation guidelines for patients with all types of AF. Adherence to warfarin treatment at hospital discharge was assessed in eligible patients with AF who presented with stroke or transient ischemic attack, based on type of AF. Of patients with stroke, 10.5% presented with some form of AF. When AF was documented using electrocardiography or telemetry (ECG) during the present admission, eligible patients were more likely to receive warfarin compared with patients for whom AF was reported using medical history only (78.8% vs 49.4%; p<0.0001). Improvement after GWTG-S participation in warfarin use was observed in patients with ECG-documented AF (73.8% at baseline vs 88.5% after the intervention; p<0.0001), but not patients using history only. Women and elderly patients were less likely to receive warfarin, and these gaps in treatment did not narrow during the quality improvement program for patients with ECG-documented AF and those with history only. In conclusion, anticoagulation for stroke prevention was underused in general for patients with AF, even in such high-risk groups as patients with stroke. GWTG-S was associated with improved adherence for patients with ECG-documented AF, but patients with a history of AF alone were largely untreated.

Potentially Preventable Strokes in High-Risk Patients With Atrial Fibrillation Who Are Not Adequately Anticoagulated

Background and Purpose— Warfarin is the most effective stroke prevention medication for high-risk individuals with atrial fibrillation, yet it is often underused. This study examined the magnitude of this problem in a large contemporary, prospective stroke registry.

Methods— We analyzed data from the Registry of the Canadian Stroke Network, a prospective database of consecutive patients with stroke admitted to 12 designated stroke centers in Ontario (2003 to 2007). We included patients admitted with an acute ischemic stroke who (1) had a known history of atrial fibrillation; (2) were classified as high risk for systemic emboli according to published guidelines; and (3) had no known contraindications to anticoagulation. Primary end points were the use of prestroke antithrombotic medications and admission international normalized ratio.

Results— Among patients admitted with a first ischemic stroke who had known atrial fibrillation (n=597), strokes were disabling in 60% and fatal in 20%. Preadmission medications were warfarin (40%), antiplatelet therapy (30%), and no antithrombotics (29%). Of those taking warfarin, three fourths had a subtherapeutic international normalized ratio (<2.0) at the time of stroke admission. Overall, only 10% of patients with acute stroke with known atrial fibrillation were therapeutically anticoagulated (international normalized ratio ≥2.0) at admission. In stroke patients with a history of atrial fibrillation and a previous transient ischemic attack or ischemic stroke (n=323), only 18% were taking warfarin with therapeutic international normalized ratio at the time of admission for stroke, 39% were taking warfarin with subtherapeutic international normalized ratio, and 15% were on no antithrombotic therapy.

Conclusions— In high-risk patients with atrial fibrillation admitted with a stroke, and who were candidates for anticoagulation, most were either not taking warfarin or were subtherapeutic at the time of ischemic stroke. Many were on no antithrombotic therapy. These findings should encourage greater efforts to prescribe and monitor appropriate antithrombotic therapy to prevent stroke in individuals with atrial fibrillation.

Warfarin reversal in anticoagulant-associated intracerebral hemorrhage

Anticoagulant-associated intracerebral hemorrhage (ICH) is a devastating disease, causing death in half of patients and permanent disability in the majority of survivors. The finding that patients often continue bleeding after hospital presentation offers the possibility that emergency warfarin reversal may improve outcomes. As no clinical trials have demonstrated the superiority of any one treatment strategy, various treatment options are available. Intravenous vitamin K is the definitive therapy; however, as monotherapy it can require many hours to take effect. Therefore, it is often considered an adjunct agent. Coagulation factors can be repleted with fresh frozen plasma (FFP), which is widely available and relatively low cost, but can require substantial time to deliver in real-world settings. A number of coagulation factor products collectively termed prothrombin complex concentrates (PCCs) are widely available that can rapidly provide many or all the vitamin K-dependent coagulation factors. Recombinant activated factor VII is used in many centers for this purpose, as it is thought to provide a procoagulant effect that may compensate for the lack of the other critical factors. Until clinical trials demonstrate the superiority of any one means of warfarin reversal, a number of expert guidelines from national organizations are available to help local providers guide therapy. At our institution, we have focused on improving the rapid and reliable delivery of a combination of intravenous vitamin K and FFP, with continued re-dosing until the desired INR lowering is achieved.

Comparison of the Impact of the Atrial Fibrillation Follow-Up Investigation of Rhythm Management Trial on Prescribing Patterns: A Time-Series Analysis

Background:

The AFFIRM (Atrial Fibrillation Follow-Up Investigation of Rhythm Management) trial demonstrated that rate control and rhythm control strategies result in similar survival and quality of life for patients with atrial fibrillation (AF). Because of superior safety and lower cost, rate control is now the recommended strategy (or the management of most elderly, high-risk AF patients.

Objective:

To determine the extent to which the AFFIRM trial results have been adopted into actual practice.

Methods:

We conducted a time-series analysis of 3 population-based cohorts of patients with AF who were 66 years of age or older in Pennsylvania and Ontario. We stratified patients in Ontario by socioeconomic status (SES) and examined changes in quarterly prescription rates for rate control and rhythm controlling medications as well as cardioversion procedures before and after publication of the AFFIRM trial.

Results:

The publication of the AFFIRM trial resulted in statistically significant reductions in the use of rhythm controlling medications in all 3 cohorts (p < 0.01). The magnitude of these changes in the non-low SES Canadian cohort was approximately 1% per quarter and was greater than the magnitude observed in the other cohorts (p < 0.001). The use of cardioversion procedures also decreased in all study regions (p < 0.01). In contrast, AFFIRM publication was also associated with a small increase in the use of rate controlling medications in Canada (p < 0.01) but not in the US (p = 0.23).

Conclusions:

Publication of the AFFIRM trial resulted in small but statistically significant changes in the care of patients with AF.