Failure to prescribe warfarin to patients with nonrheumatic atrial fibrillation

Prescribing Trends of Oral Anticoagulants in US Patients With Cirrhosis and Nonvalvular Atrial Fibrillation

Background Many patients with cirrhosis have concurrent nonvalvular atrial fibrillation (NVAF). Data are lacking regarding recent oral anticoagulant (OAC) usage trends among US patients with cirrhosis and NVAF. Methods and Results Using MarketScan claims data (2012-2019), we identified patients with cirrhosis and NVAF eligible for OACs (CHA2DS2-VASc score ≥2 [men] or ≥3 [women]). We calculated the yearly proportion of patients prescribed a direct OAC (DOAC), warfarin, or no OAC. We stratified by high-risk features (decompensated cirrhosis, thrombocytopenia, coagulopathy, chronic kidney disease, or end-stage renal disease). Among 32 487 patients (mean age=71.6 years, 38.5% women, 15.1% with decompensated cirrhosis, mean CHA2DS2-VASc=4.2), 44.6% used OACs within 180 days of NVAF diagnosis, including DOACs (20.2%) or warfarin (24.4%). Compared with OAC nonusers, OAC users were less likely to have decompensated cirrhosis (18.6% versus 10.7%), thrombocytopenia (19.5% versus 12.5%), or chronic kidney disease/end-stage renal disease (15.5% versus 14.0%). Between 2012 and 2019, warfarin use decreased by 21.0% (32.0% to 11.0%), whereas DOAC use increased by 30.6% (7.4% to 38.0%), and among all DOACs between 2012 and 2019, apixaban was the most commonly prescribed (46.1%). Warfarin use decreased and DOAC use increased in all subgroups, including in compensated and decompensated cirrhosis, thrombocytopenia, coagulopathy, chronic kidney disease/end-stage renal disease, and across CHA2DS2-VASc categories. Among OAC users (2012-2019), DOAC use increased by 58.9% (18.7% to 77.6%). Among DOAC users, the greatest proportional increase was with apixaban (61.2%; P<0.001). Conclusions Among US patients with cirrhosis and NVAF, DOAC use has increased substantially and surpassed warfarin, including in decompensated cirrhosis. Nevertheless, >55% of patients remain untreated, underscoring the need for clearer treatment guidance.

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.

Combining Inpatient and Outpatient Data for Diagnosis of Non-Valvular Atrial Fibrillation Using Electronic Health Records: A Validation Study

Purpose

Previous studies have demonstrated differences in atrial fibrillation (AF) detection based on data from hospital sources without data from outpatient sources. We investigated the detection of documented diagnoses of non-valvular AF in a large Israeli health-care organization using electronic health record data from multiple sources.

Patients and Methods

This was an open-chart validation study. Three distinct algorithms for identifying AF in electronic health records, differing in the source of their International Classification of Diseases, Ninth Revision code and use of the associated free text, were defined. Algorithm 1 incorporated inpatient data with outpatient data and the associated free text. Algorithm 2 incorporated inpatient and outpatient data regardless of the free text associated with AF diagnosis. Algorithm 3 used only inpatient data source. These algorithms were compared to a gold standard and their sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. To establish the gold standard (documentation of arrhythmia based on electrocardiography interpretation or a cardiologist’s written diagnosis), 200 patients at highest risk for having non-valvular AF were randomly selected for open-chart validation by two physicians.

Results

The algorithm that included hospital settings, outpatient settings, and incorporated associated free text in the outpatient records had the optimal balance between all validation measures, with a high level of sensitivity (85.4%), specificity (95.0%), PPV (81.4%), and NPV (96.2%). The alternative algorithm that combined inpatient and outpatient data without free text also performed better than the algorithm that included only hospital data (82.9%, 95.0%, 81.0%, and 95.6%, compared to 70.7%, 96.9%, 85.3%, and 92.8%, sensitivity, specificity, PPV, and NPV, respectively).

Conclusion

In this study, involving a comprehensive data collection from inpatient and outpatient sources, incorporating outpatient data with inpatient data improved the diagnosis of non-valvular AF compared to inpatient data alone.

Geriatric Cardiology: An Emerging Discipline

Given changing demographics, patients with cardiovascular (CV) disease in developed countries are now older and more complex than even a decade ago. This trend is expected to continue into the foreseeable future; accordingly, cardiologists are encountering patients with a greater number of comorbid illnesses as well as "geriatric conditions," such as cognitive impairment and frailty, which complicate management and influence outcomes. Simultaneously, technological advances have widened the therapeutic options available for patients, including those with the most advanced CV disease. In the setting of these changes, geriatric cardiology has recently emerged as a discipline that aims to adapt principles from geriatric medicine to everyday cardiology practice. Accordingly, the tasks of a "geriatric cardiologist" may include both traditional evidence-based CV management plus comprehensive geriatric assessment, medication reduction, team-based coordination of care, and explicit incorporation of patient goals into management. Given that the field is still in its relative infancy, the training pathways and structure of clinical programs in geriatric cardiology are still being delineated. In this review, we highlight the rationale behind geriatric cardiology as a discipline, several current approaches by geriatric cardiology programs, and future directions for the field.

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.

Clinical and economic burden of adverse drug reactions

Adverse drug reactions (ADRs) are unwanted drug effects that have considerable economic as well as clinical costs as they often lead to hospital admission, prolongation of hospital stay and emergency department visits. Randomized controlled trials (RCTs) are the main premarketing methods used to detect and quantify ADRs but these have several limitations, such as limited study sample size and limited heterogeneity due to the exclusion of the frailest patients. In addition, ADRs due to inappropriate medication use occur often in the real world of clinical practice but not in RCTs. Postmarketing drug safety monitoring through pharmacovigilance activities, including mining of spontaneous reporting and carrying out observational prospective cohort or retrospective database studies, allow longer follow-up periods of patients with a much wider range of characteristics, providing valuable means for ADR detection, quantification and where possible reduction, reducing healthcare costs in the process. Overall, pharmacovigilance is aimed at identifying drug safety signals as early as possible, thus minimizing potential clinical and economic consequences of ADRs. The goal of this review is to explore the epidemiology and the costs of ADRs in routine care.

Documentation of atrial fibrillation prior to first-ever ischemic stroke

OBJECTIVES

We assessed the prevalence of atrial fibrillation (AF) prior to first-ever ischemic stroke by examining a comprehensive electronic ECG archive.

METHODS

The study sample comprised 336 consecutive stroke patients (median age 76 (IQ16) y, 200 men) enrolled in Lund Stroke Register from March 2001 to February 2002 and 336 age- and gender-matched controls without stroke history. AF prior to admission was studied using the regional electronic ECG database and record linkage with the National Swedish Hospital Discharge Register (SHDR). Medical records were reviewed for AF documentation and CHA2 DS2-VASc risk score.

RESULTS

Atrial fibrillation before or at stroke onset was detected in 109 (32.4%) stroke patients and 44 (13.1%) controls, P<0.001. Twenty-five of 109 stroke patients had AF detected only on previous ECG (n=14) or through the SHDR (n=11). The most prevalent type of AF in stroke group was non-permanent AF (59.6%). AF prevalence among patients admitted with sinus rhythm at hospital admission (n=266) was higher in those with CHA2 DS2 -VASc score≥6 (28.6%) than with CHA2 DS2-VASc score<6 (13.0%), P=0.043.

CONCLUSION

Comprehensive approach for AF screening allows detecting AF in one-third of patients admitted with first-ever ischemic stroke. Patients with high cardiovascular risk are more likely to have non-permanent 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.

Prevalence and management of atrial fibrillation in primary care: a case study

AIM

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major predisposing risk factor for stroke. Current UK guidelines propose stroke-risk stratification of AF patients. Anticoagulation with warfarin is recommended for high risk patients, whereas treatment with aspirin alone is advised for those at low risk. The aim of this audit was to review practice at our institution and ascertain if guidelines on AF treatment were being followed.

METHODS

A retrospective review of all patients diagnosed with non-valvular AF in June 2010 was undertaken. Patient records were reviewed to collect demographic and co-morbidity data relevant to stroke risk stratification. This was subsequently used to stratify patients according to stroke-risk using the CHADS2 scoring system. The use of anticoagulation and anti-platelet medication as well as any documented reasons for the omission of anticoagulation in high risk patients was noted.

RESULTS

The prevalence of non-valvular AF in our practice population was 1.5% (151/10,155); 70% (105/151) of AF patients were found to be at high risk of stroke; 36% (38/105) of high risk patients were not on anticoagulation and the majority (58%) of these patients had no clear reason documented for the omission of warfarin. Of the 15 patients at low risk of stroke, 12 (80%) were on warfarin. Seven (4.4%) of the 151 AF patients were on both warfarin and aspirin and six (4%) were on neither medication. The commonest documented reasons for omission of warfarin in the high risk group were dementia and a history of gastrointestinal bleeding.

DISCUSSION

The lack of documentation on withholding a proven beneficial treatment in high risk patients could potentially leave physicians open to medico-legal scrutiny. Maintaining low risk patients on anticoagulation may expose them to unnecessary risk. We recommend the use of automated audit tools designed to improve compliance with national guidelines.

Atrial fibrillation and stroke prevention

There is overwhelming evidence from randomized trials and systematic reviews to indicate the benefit of thromboprophylaxis in patients with atrial fibrillation. In moderate- to high-risk subjects, oral anticoagulation with warfarin reduces stroke by two-thirds, while aspirin reduces stroke by 22%. The latter result is similar to that seen for stroke reduction with antiplatelet therapy in vascular disease. Numerous studies have shown that less than half the patients eligible for warfarin therapy actually receive it and under- or overanticoagulation is common. This leads to many missed opportunities in optimizing stroke prevention in atrial fibrillation. The limitations of existing oral anticoagulants have resulted in the development of many new drugs. The aim of this review is to provide a brief overview of thromboprophylaxis in atrial fibrillation, and the opportunities for improvement in the provision made for thromboprophylaxis.

Antithrombotic therapy in atrial fibrillation: ximelagatran, an oral direct thrombin inhibitor

The oral direct thrombin inhibitor ximelagatran (Exanta, AstraZeneca) is rapidly absorbed, is efficiently bioconverted to the active form, melagatran (AstraZeneca) and has shown efficacy and relative safety as an anticoagulant for prophylaxis and therapy of thromboembolism. Two Phase III trials, Stroke Prevention using an ORal Thrombin Inhibitor in atrial Fibrillation (SPORTIF V), have tested the hypothesis that oral ximelagatran, administered 36 mg twice daily without coagulation monitoring or dose adjustment, prevents stroke and systemic embolism at least as effectively as adjusted-dose warfarin (international normalized ratio, 2.0-3.0) in patients with nonvalvular atrial fibrillation. Both were randomized, multicenter trials (n > 3000 per trial) with blinded end-point assessment. The open-label SPORTIF III trial confirmed the noninferiority of ximelagatran versus warfarin. Publication of the full results from SPORTIF V is pending.

Hospitalized patients with atrial fibrillation compared to those included in recent trials on novel oral anticoagulants: a population-based study

BACKGROUND

Nonvalvular atrial fibrillation is associated with a substantial risk of stroke. Novel oral anticoagulants (NOACs) with predictable anticoagulant effect and no need for routine coagulation monitoring have recently shown good results when compared with warfarin in phase III clinical trials.

OBJECTIVE

To describe clinical features and pharmacological treatments of a population-based cohort of patients with nonvalvular atrial fibrillation and ascertain whether they are comparable with those included in the three main phase III clinical trials on NOACs.

RESULTS

Of the 2,862,264 subjects considered for this study 13,360 patients (0.47%) were recently discharged from the hospital with a diagnosis of nonvalvular atrial fibrillation. Mean age was 76.3 (SD 10.7), 49.8% were men and 64.6% were ≥75 years of age. 50% of patients were treated with warfarin and 44.1% with antiplatelet agents. The proportion of patients on antiplatelet therapy increased with age up to a rate of 54.3% in subjects ≥85 years. 92.9% of the studied cohort was on polypharmacy (mean 8 drugs/patient). Around 20% of the entire cohort was treated with amiodarone, a drug potentially interfering with NOACs, and 3.6% from a subgroup analysis had renal failure, which is an exclusion criterion in trials on NOACs.

CONCLUSION

In patients recently discharged from the hospital with the diagnosis of nonvalvular AF, warfarin use decreases and aspirin treatment increases with patients' age. These patients are older, more frequently female, and on multiple medications. The benefit of NOACs in these subjects needs to be confirmed in phase IV clinical studies.

A Preliminary Assessment of the Critical Differences Between Novel Oral Anticoagulants Currently in Development

Chronic anticoagulation represents a clinical conundrum for the health care community that balances unquestionable morbidity and mortality benefits against interindividual variability, leading to drug interactions, adverse events, and thromoembolic events related to underdosing. Despite the growing data regarding the appropriate use and dosing of agents used for chronic anticoagulation, use in clinical practice remains low, thus leading to a theoretical reduction in the risk-to-benefit ratio in the clinical setting relative to that reported in the literature. Oral anticoagulants currently in development represent a heterogeneous group of compounds that are specific for the final common pathway in the coagulation cascade and show indications toward a reduced drug interaction profile, reduced interpatient variation in pharmacokinetic parameters, and morbidity and mortality benefits that might be similar to currently available treatment modalities. This review highlights the critical differences among oral anticoagulants in development and places their role in the context of the benefits and limitations of currently available anticoagulants.

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.

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.

A systematic review of validated methods for identifying atrial fibrillation using administrative data

PURPOSE

The objectives of this study were to characterize the validity of algorithms to identify AF from electronic health data through a systematic review of the literature and to identify gaps needing further research.

METHODS

Two reviewers examined publications during 1997-2008 that identified patients with atrial fibrillation (AF) from electronic health data and provided validation information. We abstracted information including algorithm sensitivity, specificity, and positive predictive value (PPV).

RESULTS

We reviewed 544 abstracts and 281 full-text articles, of which 18 provided validation information from 16 unique studies. Most used data from before 2000, and 10 of 16 used only inpatient data. Three studies incorporated electronic ECG data for case identification or validation. A large proportion of prevalent AF cases identified by ICD-9 code 427.31 were valid (PPV 70%-96%, median 89%). Seven studies reported algorithm sensitivity (range, 57%-95%, median 79%). One study validated an algorithm for incident AF and reported a PPV of 77%.

CONCLUSIONS

The ICD-9 code 427.31 performed relatively well, but conclusions about algorithm validity are hindered by few recent data, use of nonrepresentative populations, and a disproportionate focus on inpatient data. An optimal contemporary algorithm would likely draw on inpatient and outpatient codes and electronic ECG data. Additional research is needed in representative, contemporary populations regarding algorithms that identify incident AF and incorporate electronic ECG data.

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.

Risk factors for bleeding during anticoagulation of atrial fibrillation in older and younger patients in clinical practice

BACKGROUND

The prevalence of atrial fibrillation increases with age, affecting approximately 5% of people aged >65 years and almost 10% of people aged >80 years.

OBJECTIVE

The goal of this study was to identify risk factors for bleeding during warfarin treatment of nonvalvular atrial fibrillation (NNVAF) in older patients (those aged >or=75 years) compared with younger patients (those aged <75 years) in clinical practice.

METHODS

All patients with NVAF newly started on warfarin at an anticoagulation clinic in a large university hospital were included in this prospective observational study. Patient details were recorded at their first visit; details of any bleeding events were recorded via telephone interview every 4 to 6 weeks for a minimum of 10 months. Patients were divided into 2 groups (ie, those >or=75 years old and those <75 years old). Logistic regression analysis was used to identify risk factors for bleeding.

RESULTS

A total of 402 patients were included in the study. Group I comprised 203 patients <75 years old (mean [SD] age, 64.33 [8.33] years) and group II comprised 199 patients >or=75 years old (mean [SD] age, 80.44 [3.99] years). Follow-up ranged from 1 to 31 months (mean [SD], 19 [8.11] months). For major bleeding, number of medications was a significant risk factor in older patients (odds ratio [OR], 3.0; 95% CI, 1.2-7.8 [P = 0.02 ]) and range of the international normalized ratio (INR) was a significant risk factor in both groups. For every unit increase in the range of INR, the odds of major bleeding increased by 0.6 (OR, 1.6; 95% CI, 1.2-2.4 [P = 0.03 ]) in younger patients and by 0.4 (OR, 1.4; 95% CI, 1.07-1.99 [P = 0.04 ])in older patients. For minor bleeding, history of hypertension was the only significant risk factor in older patients (OR, 3.3; 95% CI, 1.3-8.1 [P = 0.01 ]), while history of ischemic heart disease was the only risk factor in younger patients (OR, 1.9; 95% CI, 1.1-5.4 [P = 0.04 ]).

CONCLUSIONS

Bleeding pattern was similar in both age groups regarding severity, onset, anatomic site of bleeding, and INR values during the bleeding event. Risk factors for episodes of major bleeding, which are more of a clinical concern, are potentially modifiable. They include quality of anticoagulation control in both groups and number of medications in the older age group.

Influence of age on the prescription of vitamin K antagonists in outpatients with permanent atrial fibrillation in France

PURPOSE

The aim of the study was to describe the current rate and determinants of the prescription of antithrombotics in outpatients with permanent atrial fibrillation, with a pre-specified emphasis on the influence of age on the prescription of vitamin K antagonists.

METHODS

This was a prospective observational survey in France among 5893 consecutive outpatients with documented permanent atrial fibrillation being seen by 770 physicians from August to December 2002. We recruited physicians from two random lists of general practitioners and cardiologists, respectively, stratified according to their administrative region, from the list of all French private general practitioners and cardiologists.

RESULTS

The mean age of patients was 75.8 years. Mean duration since diagnosis of atrial fibrillation was 5.0 years; 31.7% of patients had valvular heart disease and 60.3% hypertension. An antithrombotic was prescribed to 95.5% of patients at the time of consultation. The percentage of patients treated with vitamin K antagonists was 76.4%; it decreased from 86.0% in patients aged 60-70 years to 63.5% in patients aged 80 years or above. On multivariate analysis, high age was a significant predictor (p = 0.001) for the non-prescription of vitamin K antagonists. In patients above 70 years currently receiving an antithrombotic, the probability of prescription of vitamin K antagonists decreased on average by 9.6% per year.

CONCLUSIONS

Vitamin K antagonists are administered to most outpatients with permanent atrial fibrillation at high thromboembolic risk seen by French physicians in private practice. However, their use decreases with age.

Influence of decision aids on patient preferences for anticoagulant therapy: a randomized trial

BACKGROUND

Decision aids have been shown to be useful in selected situations to assist patients in making treatment decisions. Important features such as the format of decision aids and their graphic presentation of data on benefits and harms of treatment options have not been well studied.

METHODS

In a randomized trial with a 3 x 2 factorial design, we investigated the effects of decision aid format (decision board, decision booklet with audiotape, or interactive computer program) and graphic presentation of data (pie graph or pictogram) on patients' comprehension and choices of 3 treatments for anticoagulation, identified initially as "treatment A" (warfarin), "treatment B" (acetylsalicylic acid) and "treatment C" (no treatment). Patients aged 65 years or older without known atrial fibrillation and not currently taking warfarin were included. The effect of blinding to the treatment name was tested in a before-after comparison. The primary outcome was change in comprehension score, as assessed by the Atrial Fibrillation Information Questionnaire. Secondary outcomes were treatment choice, level of satisfaction with the decision aid, and decisional conflict.

RESULTS

Of 102 eligible patients, 98 completed the study. Comprehension scores (maximum score 10) increased by an absolute mean of 3.1 (p < 0.01) after exposure to the decision aid regardless of the format or graphic presentation. Overall, 96% of the participants felt that the decision aid helped them make their treatment choice. Unblinding of the treatment name resulted in 36% of the participants changing their initial choice (p < 0.001).

INTERPRETATION

The decision aid led to significant improvement in patients' knowledge regardless of the format or graphic representation of data. Revealing the name of the treatment options led to significant shifts in declared treatment preferences.

Patterns and predictors of warfarin use in patients with new-onset atrial fibrillation from the FRACTAL Registry

Warfarin is underused for stroke prevention in atrial fibrillation (AF). Previous studies addressing this have lacked longitudinal assessment. This study sought to characterize contemporary warfarin use in new-onset AF and evaluate its change over time. It was hypothesized that AF recurrence has an important influence on warfarin use patterns. One thousand five adults from 17 centers in the United States and Canada were enrolled into a prospective observational registry after their first documented episodes of AF. Detailed demographic, clinical history, and management data were collected on all subjects at enrollment, including medication use. Patients were followed at regular intervals for interim events and changes in AF management. Warfarin use at baseline and last follow-up (mean 25 +/- 8 months) after enrollment was modeled using multivariate analysis. Initially, 65% of subjects were prescribed warfarin, but only 44% were taking it at 30 months. Even in "ideal" candidates for warfarin, the rate of warfarin prescription decreased from 70% at baseline to 50% at 30 months. Stroke risk factors, including hypertension, congestive heart failure, valvular heart disease, and previous stroke or transient ischemic attack were significant predictors of warfarin prescription at baseline. At last follow-up, the relation between AF recurrence and warfarin use (odds ratio 2.3, 95% confidence interval 1.6 to 3.1) was stronger than that for any individual stroke risk factor. In conclusion, predictors of warfarin use in patients with AF include AF recurrence and selected stroke risk factors. The discontinuation of warfarin in a large number of patients with AF over time is a cause for concern in light of data from recent clinical trials.

Hospitalized Patients With Atrial Fibrillation and a High Risk of Stroke Are Not Being Provided With Adequate Anticoagulation

OBJECTIVES

The purpose of this study was to determine both treatment gaps and predictors of warfarin use in atrial fibrillation (AF) patients enrolled in a national multicenter study.

BACKGROUND

The National Anticoagulation Benchmark Outcomes Report (NABOR) is a performance improvement program designed to benchmark anticoagulation prophylaxis, treatment, and outcomes among participating hospitals.

METHODS

A retrospective cohort study of inpatients was performed at 21 teaching, 13 community, and 4 Veterans Administration hospitals in the U.S. Patients with an ICD-9-CM code for AF (427.31) were randomly selected.

RESULTS

Among the 945 patients studied, the mean age was 71.5 (+/- 13.5) years; 43% were >75 years of age, 54.5% were men, and 67% had a history of hypertension. Most (86%) had factors that stratified them as at high risk of stroke, and only 55% of those received warfarin. Neither warfarin nor aspirin were prescribed in 21% of high-risk patients, including 18% of those with a previous stroke, transient ischemic attack, or systemic embolic event. Age >80 years (p = 0.008) and perceived bleeding risk (p = 0.022) were negative predictors of warfarin use. Persistent/permanent AF (p < 0.001) and history of stroke, transient ischemic attack, or systemic embolus (p = 0.014) were positive predictors of warfarin use, whereas high-risk stratification was not.

CONCLUSIONS

This study confirms the under-use of warfarin, but also adds to published reports in several regards. It showed that risk stratification, the guidepost for treatment in international guidelines, had little effect on warfarin use, and that age >80 years and AF classification (permanent/persistent) are factors that influence warfarin use.

Bleeding Risk Index in an anticoagulation clinic. Assessment by indication and implications for care

BACKGROUND

The Outpatient Bleeding Risk Index (BRI) prospectively classified patients who were at high, intermediate, or low risk for warfarin-related major bleeding. However, there are only 2 published validation studies of the index and neither included veterans.

OBJECTIVE

To determine the accuracy of the BRI in patients attending a Veterans Affairs (VA) anticoagulation clinic and to specifically evaluate the accuracy of the BRI in patients with atrial fibrillation.

DESIGN

Retrospective cohort study.

PATIENTS AND MEASUREMENTS

Using the BRI, all patients managed by the Anticoagulation Clinic between January 1, 2001 and December 31, 2002 were classified as high, intermediate, or low risk for major bleeding. Bleeds were identified via quality-assurance reports. Poisson regression was used to determine whether there was an association between the index and the development of bleeding.

RESULTS

The rate of major bleeding was 10.6%, 2.5%, and 0.8% per patient-year of warfarin in the high-, intermediate-, and low-risk groups, respectively. Patients in the high-risk category had 14 times the rate of major bleeding of those in the low-risk group (incidence rate ratio (IRR) 14; 95% confidence interval (CI), 1.9 to 104.7). The rate of major bleeding was significantly different between the high- and intermediate-risk categories (P<.001). Among those with atrial fibrillation, patients in the high-risk category had 6 times the major bleeding rate of those in the intermediate- and low-risk groups combined (IRR=6; 95% CI, 2.4 to 15.3).

CONCLUSIONS

The BRI discriminates between high- and intermediate-risk patients in a VA anticoagulation clinic, including those with atrial fibrillation.

Effect of access to anticoagulation management services on warfarin use in patients with atrial fibrillation

STUDY OBJECTIVE

To determine the effect of access to ambulatory anticoagulation management services (AMS) on the rate of warfarin use in patients with atrial fibrillation.

DESIGN

Retrospective medical record review.

SETTING

Two ambulatory care clinics in the same managed care system: one with and one without access to pharmacist-managed AMS.

PATIENTS

One hundred seventy-eight patients with atrial fibrillation diagnosed between June 2000 and June 2001.

MEASUREMENTS AND MAIN RESULTS

Warfarin use was assessed overall and by contraindications and risk factors for stroke. Independent predictors of therapy were identified. The overall rate of warfarin use in atrial fibrillation was higher in the clinic with access to AMS than in the clinic without access (77.9% vs 61.7%, p=0.03). In patients with no known contraindications, warfarin use increased by 20.2% with access to AMS versus no access (80.2% vs 60.0%, p=0.023). Patients aged 65 years or older with one or more risk factors for stroke and no contraindications were more likely to receive warfarin in the clinic with access to AMS than in the clinic without access (85.1% vs 53.8%, p=0.001). Access to AMS was an independent predictor of warfarin use (odds ratio 2.19, 95% confidence interval [CI] 1.05-4.56). Female sex was an independent negative predictor of warfarin use (odds ratio 0.48, 95% CI 0.24-0.96).

CONCLUSION

In the managed care setting, use of warfarin for stroke prophylaxis in patients with atrial fibrillation was higher in the ambulatory care clinic with access to pharmacist-managed AMS than in the clinic without access.

New treatment options for stroke prevention in atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia requiring treatment. Its most devastating consequence is thromboembolic stroke. Therapy with warfarin is indicated in most patients, as it has been shown conclusively to reduce the risk of stroke. Aspirin is an inferior alternative except in certain low-risk patients or for patients with an absolute contraindication to warfarin. Guidelines have been published for the administration of antithrombotic therapy in AF, but many patients who are candidates for anticoagulation do not receive this therapy. Even as this therapy is under-utilized, the indication for anticoagulation is expanding. Indefinite continuation of anticoagulation should be considered in higher-risk patients despite the appearance that sinus rhythm has been restored because asymptomatic (or silent) AF occurs frequently. Newer agents that offer substantial benefit over warfarin are being developed and would enhance compliance with anticoagulation in AF if these novel therapies prove to be safe and equivalent to warfarin in efficacy.

Prognostic implications of warfarin cessation after major trauma: a population-based cohort analysis

BACKGROUND

Warfarin therapy is often withheld from elderly patients who fall or otherwise experience injury because of concerns regarding the long-term risk of hemorrhage in these individuals. We studied whether stopping warfarin after trauma is associated with a higher risk of subsequent adverse cardiovascular events.

METHODS AND RESULTS

We conducted a retrospective, population-based, cohort study using linked administrative databases in the province of Ontario, Canada for the years 1992 to 2001. A total of 8450 elderly patients (age >65 years) who survived an incident of major trauma and were receiving warfarin before injury were followed up for a mean of 3.3 years. During the 6-month interval after trauma, 1827 (22%) patients discontinued warfarin, whereas 6623 (78%) patients continued warfarin. Warfarin cessation was not associated with an increased risk of subsequent stroke (hazard ratio [HR] 0.99, 95% CI 0.82 to 1.21) or myocardial infarction (HR 0.94, 95% CI 0.74 to 1.20) but was associated with a lower risk of major hemorrhage (HR 0.69, 95% CI 0.54 to 0.88) and a higher risk of venous thromboembolism (HR 1.59, 95% CI 1.07 to 2.36). Adjustment for baseline demographics, stroke risk factors, other comorbidities, and characteristics of the trauma did not materially change these findings. On-treatment analyses yielded similar results.

CONCLUSIONS

Cessation of warfarin in elderly patients after major trauma was not associated with an increased risk of arterial thrombotic events but was associated with a significantly increased risk of venous thromboembolism.

External validity of randomised controlled trials: "to whom do the results of this trial apply?"

In making treatment decisions, doctors and patients must take into account relevant randomised controlled trials (RCTs) and systematic reviews. Relevance depends on external validity (or generalisability)--ie, whether the results can be reasonably applied to a definable group of patients in a particular clinical setting in routine practice. There is concern among clinicians that external validity is often poor, particularly for some pharmaceutical industry trials, a perception that has led to underuse of treatments that are effective. Yet researchers, funding agencies, ethics committees, the pharmaceutical industry, medical journals, and governmental regulators alike all neglect external validity, leaving clinicians to make judgments. However, reporting of the determinants of external validity in trial publications and systematic reviews is usually inadequate. This review discusses those determinants, presents a checklist for clinicians, and makes recommendations for greater consideration of external validity in the design and reporting of RCTs.

Current Issues in Anticoagulation

Anticoagulation therapy with unfractionated heparin, low-molecular-weight heparins and oral vitamin K antagonists is currently the mainstay of treatment and prevention of thromboembolic disorders (such as deep vein thrombosis, pulmonary embolism and stroke prevention in patients with atrial fibrillation). Although these therapies have proven benefits, they also have important limitations that result in their underuse in routine clinical practice. Consequently, many patients identified by guidelines as requiring anticoagulant therapy receive no or inadequate treatment. Heparins require parenteral administration and pose the risk of heparin-induced thrombocytopenia. Vitamin K antagonists have a narrow separation of antithrombotic and haemorrhagic effects and numerous food and drug-drug interactions, and require frequent coagulation monitoring and dose adjustment to ensure effective antithrombotic protection while minimizing the risk of bleeding complications. In response to these limitations, several new anticoagulants have recently been developed, including selective factor Xa inhibitors such as fondaparinux and ximelagatran, the first oral agent in the new class of direct thrombin inhibitors and the first new oral anticoagulant for almost 60 years. Ximelagatran possesses many of the properties of an ideal agent for anticoagulation therapy. With its oral formulation, consistent and predictable pharmacological profile and no coagulation monitoring, ximelagatran has the potential to increase the use and duration of anticoagulation treatment in thromboembolic disorders and to reduce the burden associated with long-term management.

Physicians' attitudes toward anticoagulant therapy in patients with chronic atrial fibrillation

INTRODUCTION

Although many clinical trials have demonstrated that anticoagulant therapy substantially reduces the risk of ischemic stroke in patients with atrial fibrillation (AF), some physicians are reluctant to use anticoagulants. We investigated attitudes of physicians in Japan toward anticoagulant therapy in chronic AF patients.

METHODS

We conducted a survey at the annual meeting of the Japanese Society of General Medicine. We presented subject physicians with 8 vignettes of chronic AF patients and requested that they indicate their most favored choice of therapy from among 6 strategies including warfarin and aspirin.

RESULTS

We distributed 209 questionnaires and received 139 replies (67% response rate). For all 8 vignettes presented, only 26% of the respondents preferred to use anticoagulant therapy in AF patients. Longer clinical experiences and responsibility at a teaching hospital were associated with negative attitude toward anticoagulant therapy, while experience of preventive therapy in patients with thromboembolism due to AF and strong influence of clinical trials of anticoagulant prophylaxis on their practice were associated with positive attitude toward the therapy. Among patient characteristics in the vignettes, a risk of thromboembolism was positively associated with preference for anticoagulant therapy, but an advanced age and a risk of bleeding complications were negatively associated with the preference for the therapy.

CONCLUSIONS

The physicians in Japan in this survey, especially those with longer clinical experiences or responsibility at a teaching hospital, have a negative attitude toward anticoagulant therapy in chronic AF patients. An advanced age and a risk of bleeding complications of patients are deterrent factors to the use of anticoagulant therapy.

Incidence of atrial fibrillation and thromboembolism in a randomised trial of atrial versus dual chamber pacing in 177 patients with sick sinus syndrome

OBJECTIVE

To analyse the occurrence of atrial fibrillation (AF) and thromboembolism in a randomised comparison of rate adaptive single chamber atrial pacing (AAIR) and dual chamber pacing (DDDR) in patients with sick sinus syndrome and normal atrioventricular (AV) conduction, in which left atrial dilatation and decreased left ventricular fractional shortening had been observed in the DDDR group.

METHODS

177 consecutive patients with sick sinus syndrome (mean (SD) age 74 (9) years, 104 women) were randomly assigned to treatment with one of three pacemakers: AAIR (n = 54), DDDR with a short rate adaptive AV delay (n = 60) (DDDR-s); or DDDR with a fixed long AV delay (n = 63) (DDDR-l). Analysis was intention to treat.

RESULTS

Mean follow up was 2.9 (1.1) years. AF at one or more ambulatory visits was significantly less common in the AAIR group (4 (7.4%) v 14 (23.3%) in the DDDR-s group v 11 (17.5%) in the DDDR-l group; p = 0.03, log rank test). The risk of developing AF in the AAIR group compared with the DDDR-s group was significantly decreased after adjustment for brady-tachy syndrome in a Cox regression analysis (relative risk 0.27, 95% confidence interval (CI) 0.09 to 0.83, p = 0.02). The benefit of AAIR was highest among patients with brady-tachy syndrome. Brady-tachy syndrome and a thromboembolic event before pacemaker implantation were independent predictors of thromboembolism during follow up (relative risk 7.5, 95% CI 1.6 to 36.2, p = 0.01, and relative risk 4.7, 95% CI 1.2 to 17.9, p = 0.02, respectively).

CONCLUSIONS

During a mean follow up of 2.9 years AAIR was associated with significantly less AF. The beneficial effect of AAIR was still significant after adjustment for brady-tachy syndrome. Brady-tachy syndrome was associated with an increased risk of thromboembolism.

Stroke prevention and atrial fibrillation: reasons leading to an inappropriate management. Main results of the SAFE II study

AIMS

The aim of the Stroke and Atrial Fibrillation Ensemble (SAFE) II study was to identify the reasons underlying the under-utilization of oral anticoagulation (OAC) in patients with nonvalvular atrial fibrillation (NVAF).

METHODS

We investigated from all available sources the reasons why patients hospitalized for a stroke, who had a previously known NVAF, were not receiving OAC beforehand. We interviewed general practitioners (GPs) and cardiologists with a structured questionnaire, to identify the reasons for their therapeutic choice.

RESULTS

Of 370 patients, 257 were theoretically eligible for OAC according to guidelines and the presence of contra-indications, but only 82 (22.2%) of them had actually received OAC before. We found that factors independently associated with the prescription of OAC were being followed-up by a cardiologist and having a younger GP. The leading reason evoked by GPs or cardiologists to explain why patients were not treated with OAC was the presence of a 'potential contra-indication', which was often inappropriate, followed by 'there was no indication', 'low compliance' and 'fear of bleeding'.

CONCLUSIONS

An important reason for not prescribing OAC was the lack of knowledge about trials and guidelines. Medical education about OAC in NVAF should therefore be improved.

A randomized trial to assess the impact of an antithrombotic decision aid in patients with nonvalvular atrial fibrillation: the DAAFI trial protocol [ISRCTN14429643]

BACKGROUND

Decision aids are often advocated as a means to assist patient and health care provider decision making when faced with complicated treatment or screening decisions. Despite an exponential growth in the availability of decision aids in recent years, their impact on long-term treatment decisions and patient adherence is uncertain due to a paucity of rigorous studies. The choice of antithrombotic therapy for nonvalvular atrial fibrillation (NVAF) is one condition for which a trade-off exists between the potential risks and benefits of competing therapies, and the need to involve patients in decision making has been clearly identified. This study will evaluate whether an evidence-based patient decision aid for patients with NVAF can improve the appropriateness of antithrombotic therapy use by patients and their family physicians.

DESIGN

A multi-center, two-armed cluster randomized trial based in community family practices in which patients with NVAF will be randomized to decision aid or usual care. Patients will receive one of four decision aids depending on their baseline stroke risk. The primary outcome is the provision of "appropriate antithrombotic therapy" at 3 months to study participants (appropriateness defined as per the 2001 American College of Chest Physicians recommendations for NVAF). In addition, the impact of this decision aid on patient knowledge, decisional conflict, well-being, and adherence will be assessed after 3 months, 6 months, and 12 months.

A multidisciplinary guideline for the acute phase of stroke: barriers perceived by Dutch neurologists

RATIONALE, AIMS AND OBJECTIVES

Guidelines for stroke management should improve quality of care. Dissemination of guidelines, however, does not guarantee guideline adherence. The aim of this paper is to investigate barriers for guideline adherence to bring about suggestions for possible implementation strategies.

METHOD

Questionnaire survey among all Dutch neurologists working on neurology wards in general hospitals during the year 2000 in The Netherlands.

RESULTS

The neurologists expressed a high degree of agreement with the diagnostic and preventive recommendations, but expressed doubts with regard to the therapeutic recommendations, especially for the recombinant tissue plasminogen activator therapy. In general, barriers at the organizational and the multidisciplinary team level were most prominent.

CONCLUSIONS

Active implementation of the guidelines seems necessary. Implementation strategies should be focused on the different sources of barriers: the caregiver, the patient and the organization of care.

Use of resources and cost implications of stroke prophylaxis with warfarin for patients with nonvalvular atrial fibrillation

BACKGROUND

Patients with nonvalvular atrial fibrillation (NVAF) have often been excluded from long-term anticoagulant trials, and therefore patients in clinical practice may have different risk, compliance, and safety considerations from those usually included in such trials.

OBJECTIVE

The aim of this study was to investigate the use of resources and cost implications of stroke prophylaxis with warfarin in NVAF patients in clinical practice.

METHODS

New patients with NVAF referred to an anticoagulation clinic in the United Kingdom were interviewed in person at their first visit and then by telephone every 4 to 6 weeks by an investigator. They were asked about bleeding events and extra physician visits, procedures, or hospital admissions related to bleeding. They were also asked about the method and the cost of transportation to the anticoagulation clinic and the costs involved in days of work missed by the patient and caregiver. Costs of warfarin treatment consisted of the following: (1) cost of the drug, (2) cost of monitoring lie, international normalized ratio, traveling, nurse visits, work missed. postage), and (3) costs associated with complications (ie, bleeding-related physician visits, hospital admissions, related procedures). admissions, related procedures).

RESULTS

A total of 402 patients were included. Mean (SD) age was 72.3 (10.3) years, and 224 patients (55.7%) were men. Mean (SD) follow-up was 19 (8.1) months (range, 1-31 months). Annual event rates were 1.7% (95% CI, 0.4-3.0) for major bleeding and 16.6% (95% CI, 13.0-20.2) for minor bleeding. The mean cost of warfarin treatment per patient per month was 11.0 pounds (95% CI, 10.2-11.6) in patients with no bleeding and 11.9 pounds (95% CI, 10.3-12.5) in patients with minor bleeding (P=NS). The cost was significantly higher in patients with major bleeding ( 299.0 pounds; 95% CI, 74.6-538.9; P<0.001). The total cost of warfarin treatment per patient per year was 159.4 pounds, and the cost to prevent 1 stroke per year was 5260.20 pounds.

CONCLUSION

In clinical practice in the United Kingdom, anticoagulation with warfarin for prevention of ischemic stroke appeared to be cost-saving relative to the costs of stroke.

Utilización de anticoagulantes orales en pacientes con fibrilación auricular al alta hospitalaria en el año 2000

INTRODUCTION AND OBJECTIVES

Although there is consensus about the use of oral anticoagulants to prevent thrombi and embolisms in most patients with atrial fibrillation, this treatment is underused in actual practice. Our objective was to determine and analyze the use of acenocoumarol in patients diagnosed as having atrial fibrillation at discharge.

PATIENTS AND METHOD

Between January and July 2000, we retrospectively studied 501 consecutive patients with a diagnosis of atrial fibrillation. We recorded whether they were discharged with or without oral anticoagulation treatment.

RESULTS

We identified 482 patients with at least one associated thromboembolic risk factor, who comprised the study population. Mean age was 79.3 years, and 33.3% of the patients were men. Forty-six percent were discharged with acenocoumarol, and 36.3% with platelet antiaggregants. Twenty-three percent had a known contraindication for acenoroumarol. Nearly 62% of the patients without contraindications for anticoagulation received treatment with acenocoumarol. Multivariate analysis showed that rheumatic mitral valve disease, previous stroke or thromboembolism and dilated left atrium were associated with a higher probability of receiving anticoagulant treatment. Age over 75 years was associated with a lower likelihood of receiving acenocoumarol.

CONCLUSIONS

Oral anticoagulation was given in an inadequate proportion of patients who were discharged from a secondary-level hospital with atrial fibrillation and no contraindications. Rheumatic mitral valve disease, previous stroke or thromboembolism, and dilated left atrium were associated with a higher probability of anticoagulant treatment. Age over 75 years was related with less frequent use of this therapy.

Anticoagulants for atrial fibrillation: why is the treatment rate so low?

The incidence of atrial fibrillation (AF) is increasing in many countries along with aging demographics. Atrial fibrillation is clearly associated with an increased rate of stroke. Numerous large clinical trials have shown that dose-adjusted warfarin can reduce the stroke rate in these patients, particularly in the elderly, and clear guidelines for the use of anticoagulants in such patients have been published. However, many studies show that treatment rates remain disappointingly low (< or = 50%). Numerous barriers to the use of dose-adjusted warfarin exist, including practical, patient-, physician-, and healthcare system-related barriers. These include the complex pharmacokinetics of warfarin, the need for continuous prothrombin time monitoring and dose adjustments, bleeding events, noncompliance, drug interactions, and increased costs of monitoring and therapy. Possible solutions to this problem are discussed and include improved patient and physician education, the use of anticoagulation clinics, new approaches to AF, and potential treatment improvements through use of newer anticoagulants.

Principles of drug therapy in older patients: rational drug prescribing

Health care providers must be aware of the issues involved in using drugs therapies in older patients because older patients are very vulnerable to the adverse effects of drugs. Although more data are needed to guide clinical decision making in prescribing drugs to older patients, some simple considerations can make drug use safer and more effective (Table 10). Careful, compassionate attention to these factors can have a profound effect on improving the quality of life, medication use, and the overall cost of health care in this vulnerable population.

The morbidity related to atrial fibrillation at a tertiary centre in one year: 9.0% of all strokes are potentially preventable

Atrial fibrillation is a major risk factor for stroke. Anticoagulant therapy reduces this risk but increases the risk of haemorrhage. We aimed to compare the morbidity related to the treatment of atrial fibrillation with warfarin seen in one year at our hospital, with the morbidity in those patients in whom embolism was potentially preventable. There were 111 patients admitted to our hospital in a 12 month period with nonvalvular atrial fibrillation (NVAF) who had stroke, TIA or peripheral embolism. Atrial fibrillation was identified prior to admission in 87 of these 111 (78%) patients with thromboembolism, yet only 14 of these (16%) were receiving warfarin for stroke prophylaxis. Through chart review, a further 56 (64%) patients with embolism could have been receiving anticoagulant therapy if published clinical guidelines(1) were applied. Therefore, 40 episodes of thromboembolism were potentially preventable. Over the same period, there were 18 patients admitted with haemorrhage related to warfarin therapy for stroke prophylaxis in NVAF, including 10 gastrointestinal, five intracerebral, and three peripheral haemorrhages. Most haemorrhages were associated with a high International Normalized Ratio (INR) and the patients were left less disabled than those with embolism. Only one patient with haemorrhage had an absolute contraindication to warfarin therapy (6%). We conclude that the number of preventable strokes far outweighed the morbidity due to warfarin use in the management of NVAF.

[Antithrombotic treatment in hypertensive patients with chronic atrial fibrillation. CARDIOTENS 99 study]

BACKGROUND

Our main goals were to know the actual degree of oral anticoagulation and antiaggregation in hypertensive patients with atrial fibrillation in the daily clinical practice in Spain and to analyze any differences between primary care physicians and cardiologists.

PATIENTS AND METHOD

32,051 outpatients attended the same day by 1,159 physicians (21% cardiologists) were prospectively included in a database taking into account a history of hypertension and atrial fibrillation, demographic data and ongoing treatments.

RESULTS

Hypertension was detected in 10,555 patients and 999 of them had both hypertension and atrial fibrillation (9.46%: 435 males [44%] and 564 females [56%]). 53% patients were attended by primary care physicians and the rest by cardiologists. 33% of hypertensive patients with atrial fibrillation were on oral anticoagulation: 41% of them attended by cardiologists and 26% by primary care physicians (p < 0.05). These differences persisted when the patients were compared on the basis of their age. 39% of hypertensive patients were on oral antiaggregation treatment, without differences in both groups except for those aged less than 65 years who were found to receive more antiaggregation in primary care (36% vs 24%; p < 0.05).

CONCLUSIONS

The prevalence of atrial fibrillation in hypertensive patients is about 10%; there is a suboptimal degree of utilization of oral anticoagulation, which is more evident in patients attended by primary care physicians; elderly patients (> 80 years-old) were found to receive less anticoagulants and more antiaggregants both in primary health-care and cardiology health-care.