Service provision and use of anticoagulants in atrial fibrillation

Moving towards ideal and appropriate models of anticoagulation management service

It is now known that thrombotic disorders such as venous thromboembolism, ischemic stroke, and myocardial infarction contribute significantly to global morbidity and mortality. Anticoagulation service must respond to this new development. Warfarin has continued to provide the backbone for anticoagulation service for decades but with considerable drawbacks. The introduction of nonVitamin K oral anticoagulants (NOACs) has created new challenges. This article seeks to discuss how the establishment of appropriate models of anticoagulation could contain the draw backs of the old anticoagulants and improve on the compliance, availability, affordability, and accessibility of newer anticoagulants. Successful anticoagulation has always been defined by a scientific balancing of the risk of thrombosis and the complication of hemorrhage. To be able to maintain such optimal anticoagulation requires rational drug prescription (physician factor), institutelization of monitoring of therapy (anticoagulation clinic factor) as well as active participation of patients receiving therapy (patient factor). New models of service can be created out of this triad in a bid to replace the old routine medical care model. New models of anticoagulation service should include appropriately trained professionals such as Physicians, Pharmacists, Clinical Pharmacologists, Nurses, and Laboratory Scientists who are knowledgeable in diagnostic, management, and monitoring of anticoagulation. The different models of anticoagulation service discussed in this article clearly demonstrate the need for restructuring of this life saving service particularly in the era of NOAC. Newer models of care that should provide safe, efficacious, and cost-effective services are needed.

Treatment Satisfaction Questionnaire for Medication: Validation of the Translated Arabic Version among Patients Undergoing Warfarin Therapy in Saudi Arabia

OBJECTIVES

To validate the psychometric properties of the translated Arabic version of the Treatment Satisfaction Questionnaire for Medication (TSQM 1.4) for patients on warfarin therapy in Saudi anticoagulation clinics (ACCs).

METHODS

A cross-sectional survey was conducted at the Security Forces Hospital ACC in Riyadh, Saudi Arabia. It involved administering questionnaires related to patients' satisfaction and assessing adherence through interviews. The quality of the international normalized ratio control was assessed using the Rosendaal method. A psychometric evaluation of TSQM 1.4 was carried out, addressing internal consistency and known-groups and convergent validity.

RESULTS

A total of 101 patients completed the questionnaire with an 80% response rate. The independent Cronbach α values for the effectiveness, side effects, and global satisfaction domains were consistently higher than 0.75, demonstrating good internal consistency and suitability of these domains for application in the current patients' setting. When these domains were used together in a multivariable logistic regression model of adherence, the only domain that remained significant was TSQM effectiveness (P = 0.017). Interestingly, a higher likelihood of moderate to optimal international normalized ratio control was significantly and independently associated with increased satisfaction scores in the effectiveness and convenience domains, but not in the side effects and global satisfaction domains.

CONCLUSIONS

This study provides evidence in favor of the reliability and validity of the Arabic version of TSQM 1.4 as a useful measure of satisfaction with anticoagulant therapy in patients visiting ACCs. The TSQM subscales in this patient setting seem to detect a clinically meaningful change over time, enhancing the potential of their use in routine practice.

Validation of knowledge and adherence assessment tools among patients on warfarin therapy in a Saudi hospital anticoagulant clinic

Background Although it can result in serious complications due to its narrow therapeutic index, warfarin is widely used in the treatment and prevention of thromboembolic disorders. However, patients' adherence and knowledge are determinants of therapeutic success. Objective We sought to validate instruments to provide a reliable means of identifying gaps in patient understanding and nonadherence to inform targeted pharmacists' interventions to improve these measures. Methods A cross-sectional survey was conducted. Patients' knowledge about warfarin was rated using an Arabic-language tool. Medication adherence was assessed using the eight-item Morisky Medication Adherence Scale (MMAS-8). The international normalized ratio (INR) control was quantified by the Rosendaal Method. Setting At the Security Forces hospital anticoagulant clinic (ACC), Riyadh. Main outcome measure Validity of a Knowledge and adherence tool. Results Totally, 101 patients completed the questionnaires. Interestingly, the knowledge tool demonstrated good internal consistency (total Cronbach's alpha = 0.75) and significant concurrent validity with adherence levels. Fifty-two patients were classified as having unsatisfactory knowledge. Deficiency in knowledge was most obvious with respect to the consequences of missing a dose and when to seek immediate medical attention. The MMAS-8 had moderate reliability (Cronbach's alpha = 0.65); however, its concurrent validity with good INR control was not demonstrated. Conclusions This study revealed high prevalence of nonadherence and poor knowledge in the population visiting the ACC. Given that available knowledge and adherence tools seemed to have little validity in predicting clinical outcomes, structured tools should be designed, considering progression in clinical outcomes with future pharmacists' interventions.

Oral Anticoagulation in the Elderly: New Oral Anticoagulants-Innovative Solution for an Old Problem?

Direct oral anticoagulants emerge as the most innovative and promising drug toward preventing and treating cardiovascular disease, raising great interest among the scientific community. Numerous studies and meta-analysis generated much data clarifying clinicians' doubts; however, uncertainties remain regarding their use in particular groups such as patients with prosthetic valves, in valvular atrial fibrillation (defined as atrial fibrillation related to mitral rheumatic heart disease or prosthetic heart valves), among the elderly, in paraneoplastic thromboembolism, in pulmonary embolism with hemodynamic compromise, and scarcity of specific antidotes. This review article intends to condense the vast scientific production addressing new oral anticoagulants by focusing on their advantages and disadvantages when used on the elderly.

Characterization of the proportion of untreated and antiplatelet therapy treated patients with atrial fibrillation

Despite the efficacy of oral anticoagulants for stroke prevention in atrial fibrillation (AF), evidence suggests that many patients with AF who should be treated with vitamin K antagonists (VKAs) are treated with antiplatelet therapy or remain untreated. The aims of this study were to determine the proportion of patients with AF in each treatment category in clinical practice and to ascertain whether treatment is appropriate for stroke risk. An extensive search of the biomedical research published since 1994 was performed. Studies delineating the treatment of patients with AF were captured. Seventy-eight studies pertaining to the treatment of patients with AF were identified; 56 studies, containing data from 1980 to 2007, met the inclusion criteria. Over time, the use of VKA therapy for stroke prevention increased, while the proportion of untreated patients decreased; antiplatelet use remained static. Looking at the more recent data, (collected from 2000 onward), the proportion of patients receiving no therapy ranged from 4% to 48% (median 18%), antiplatelet therapy from 10% to 56% (median 30%), and VKA therapy from 9% to 86% (median 52%). Although most studies showed a decrease in the proportion of antiplatelet-treated and untreated patients with increasing stroke risk (12 of 14 studies), many patients at moderate or high risk for stroke were not treated according to guidelines. In conclusion, this review shows that up to 56% of patients with AF are treated with antiplatelet therapy, and up to 48% receive no therapy regardless of stroke risk level. This may reflect the inconvenience associated with VKA use, inadequate assessment of stroke risk, or poor adherence to treatment guidelines.

Atrial fibrillation and anticoagulation in a stroke unit population

BACKGROUND

Atrial fibrillation (AF) is an important predisposing factor for ischaemic stroke. There is evidence to suggest that even in appropriate candidates warfarin therapy is underutilized. We assessed the prevalence of AF in an Australian stroke unit to determine the degree of undertreatment at presentation.

METHODS

A retrospective analysis of all patients admitted to our Stroke Unit between October 2004 and September 2006 was carried out. All patients with a diagnosis of AF, either new or old, were then selected from this group to determine the overall prevalence and anticoagulation status. Data regarding prior stroke, stroke severity and discharge anticoagulation status were also determined.

RESULTS

Data from a total of 500 patients were analysed. Our results showed that AF-related strokes accounted for a large proportion (28%) of all admissions and were associated with a larger neurological deficit. Most patients (68%) with a prior diagnosis of AF without having obvious contraindications were either not anticoagulated or under-anticoagulated when presenting with an ischaemic stroke or transient ischaemic attack.

CONCLUSION

Our results stress the importance of initiating and maintaining anticoagulation in patients with AF and without obvious contraindications to minimize the risk of subsequent stroke.

Atrial fibrillation in a primary care population: how close to NICE guidelines are we?

The National Institute for Health and Clinical Excellence (NICE) guidelines for the management of atrial fibrillation were published in June 2006. It was anticipated that they would potentially lead to increased demand for echocardiography (ECHO), increased access to secondary care services (for example for cardioversion), and require additional resources for monitoring anticoagulation. A primary care survey was therefore initiated in South Devon, in advance of publication of the guidelines as a snapshot of existing practice, to determine any additional resources and education required to meet the new standards. The main aim was to determine what proportion of patients were managed exclusively in primary care, how frequently patients were investigated by ECHO and whether anticoagulation was being appropriately targeted at patients at high risk of thromboembolic events.

Patient self-management of anticoagulation therapy: a trial-based cost-effectiveness analysis

Demand for anticoagulation management is increasing due to an expansion of clinical indications for therapy. One possible model of care to meet demand is patient self-management (PSM), beneficial to patients who need control over their condition. This study aimed to determine the cost and cost-effectiveness of PSM of anticoagulation compared with routine clinic-based care for patients receiving long-term anticoagulation. A cost-utility analysis was conducted alongside a randomised controlled trial; 617 patients were recruited and followed up for 12 months. There was no significant difference in mean quality-adjusted life years (QALYs) between groups - after adjusting for baseline, the mean difference in QALYs was 0.009 (95% CI, -0.012 to 0.030). Overall mean healthcare costs in the PSM arm were significantly higher at pounds sterling 417 (CI pounds sterling 394- pounds sterling 442) compared with pounds sterling 122 (CI pounds sterling 103- pounds sterling 144) in the control arm. Therefore, using a formal cost-effectiveness analysis, PSM of anticoagulation does not appear to be cost-effective. However, PSM may have other benefits in relieving pressure on traditional clinic-based care, and the cost-effectiveness of this model of care for some subgroups of anticoagulation patients needs to be explored further.

Oral anticoagulation control: the European perspective

We describe the results of a novel complete care package using point-of-care INR testing and computerized decision support for the management of oral anticoagulation by nurse-led primary care clinics in the United Kingdom. We found such therapy to be as safe and effective as traditional hospital-based care for oral anticoagulation in the UK as determined by adverse events or International Normalized Ratio (INR) time in range. We then review the literature as it pertains to the safety, efficacy, and cost effectiveness of patient self-management with point-of-care INR testing at home and discuss the implications for such care in the UK.

An evidence-based review and guidelines for patient self-testing and management of oral anticoagulation

There is a limited evidence base for self-testing and -management for oral anticoagulation management. Available data suggest that these are credible models for a significant minority of patients if underpinned by structured training and follow-up. The guidelines presented are necessarily consensual and outline procedures for patient selection, training, product procurement, product maintenance, quality assurance procedures, dosage adjustment and clinical supervision. The cost-effectiveness of these models remains to be elucidated within the UK. Further data on both health economic and clinical outcomes are required from UK based studies before widespread implementation of self-testing and management can be recommended on a wider scale.

Self management of oral anticoagulation: randomised trial

OBJECTIVE

To determine the clinical effectiveness of self management compared with routine care in patients on long term oral anticoagulants.

DESIGN

Multicentre open randomised controlled trial.

SETTING

Midlands region of the UK.

PARTICIPANTS

617 patients aged over 18 and receiving warfarin randomised to intervention (n = 337) and routine care (n = from 2470 invited; 193/337 (57%) completed the 12 month intervention.

INTERVENTION

Intervention patients used a point of care device to measure international normalised ratio twice a week and a simple dosing chart to interpret their dose of warfarin.

MAIN OUTCOME MEASURE

Percentage of time spent within the therapeutic range of international normalised ratio.

RESULTS

No significant differences were found in percentage of time in the therapeutic range between self management and routine care (70% v 68%). Self managed patients with poor control before the study showed an improvement in control that was not seen in the routine care group. Nine patients (2.8/100 patient years) had serious adverse events in the self managed group, compared with seven (2.7/100 patient years) in the routine care arm (chi2(df = 1) = 0.02, P = 0.89).

CONCLUSION

With appropriate training, self management is safe and reliable for a sizeable proportion of patients receiving oral anticoagulation treatment. It may improve the time spent the therapeutic range for patients with initially poor control. Trial registration ISRCTN 19313375.

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.

SMART: self-management of anticoagulation, a randomised trial [ISRCTN19313375]

BACKGROUND

Oral anticoagulation monitoring has traditionally taken place in secondary care because of the need for a laboratory blood test, the international normalised ratio (INR). The development of reliable near patient testing (NPT) systems for INR estimation has facilitated devolution of testing to primary care. Patient self-management is a logical progression from the primary care model. This study will be the first to randomise non-selected patients in primary care, to either self-management or standard care.

METHOD

The study was a multi-centred randomised controlled trial with patients from 49 general practices recruited. Those suitable for inclusion were aged 18 or over, with a long term indication for oral anticoagulation, who had taken warfarin for at least six months. Patients randomised to the intervention arm attended at least two training sessions which were practice-based, 1 week apart. Each patient was assessed on their capability to undertake self management. If considered capable, they were given a near patient INR testing monitor, test strips and quality control material for home testing. Patients managed their own anticoagulation for a period of 12 months and performed their INR test every 2 weeks. Control patients continued with their pre-study care either attending hospital or practice based anticoagulant clinics.

DISCUSSION

The methodology used in this trial will overcome concerns from previous trials of selection bias and relevance to the UK health service. The study will give a clearer understanding of the benefits of self-management in terms of clinical and cost effectiveness and patient preference.

Patient self-management of oral anticoagulation and external quality assessment procedures

The role of external quality assessment (EQA) is a contentious issue for patient self-management (PSM) of oral anticoagulation. Patients from general practices in the West Midlands undertaking PSM were recruited to compare efficacy of patients' and health professionals' EQA procedure using the UK National External Quality Assessment Scheme (NEQAS). Patients using Coaguchek (Roche Diagnostics) were trained to perform EQA as part of their PSM training. They undertook PSM for 26 weeks and were asked to perform EQA using material provided by the UK NEQAS twice at home without supervision and twice at the practice with supervision. Patients' results were compared with health care professional users of Coaguchek S. Twenty-three PSM patients were compared with 75 health care professional users of the NEQAS scheme. The PSM group international normalized ratio (INR) percentage time in range was 74%. There was no significant difference in the median results on NEQAS samples obtained by the patients and those obtained by professionals. Three patients were outwith consensus (results > 15% from the median INR) on more than one occasion. Patients were able to perform the EQA tests competently. The data show that good agreement can be achieved between patients analysing the same EQA samples, with coefficients of variation ranging from 22.3% to as low as 5.4%. Further study is required to determine how precision within these EQA schemes relates to the stability of treatment in patients' management of their own anticoagulation.

A randomised controlled trial of patient self management of oral anticoagulation treatment compared with primary care management

BACKGROUND

The increase in numbers of patients receiving warfarin treatment has led to the development of alternative models of service delivery for oral anticoagulant monitoring. Patient self management for oral anticoagulation is a model new to the UK. This randomised trial was the first to compare routine primary care management of oral anticoagulation with patient self management.

AIM

To test whether patient self management is as safe, in terms of clinical effectiveness, as primary care management within the UK, as assessed by therapeutic international normalised ratio (INR) control.

METHOD

Patients receiving warfarin from six general practices who satisfied study entry criteria were eligible to enter the study. Eligible patients were randomised to either intervention (patient self management) or control (routine primary care management) for six months. The intervention comprised two training sessions of one to two hours duration. Patients were allowed to undertake patient self management on successful completion of training. INR testing was undertaken using a Coaguchek device and regular internal/external quality control tests were performed. Patients were advised to perform INR tests every two weeks, or weekly if a dose adjustment was made. Dosage adjustment was undertaken using a simple dosing algorithm.

RESULTS

Seventy eight of 206 (38%) patients were eligible for inclusion and, of these, 35 (45%) declined involvement or withdrew from the study. Altogether, 23 intervention and 26 control patients entered the study. There were no significant differences in INR control (per cent time in range: intervention, 74%; control, 77%). There were no serious adverse events in the intervention group, with one fatal retroperitoneal haemorrhage in the control group. Costs of patient self management were significantly greater than for routine care (pound 90 v pound 425/patient/year).

CONCLUSION

These are the first UK data to demonstrate that patient self management is as safe as primary care management for a selected population. Further studies are needed to elucidate whether this model of care is suitable for a larger population.

Randomised trial of two approaches to screening for atrial fibrillation in UK general practice

BACKGROUND

Atrial fibrillation is a common and treatable cause of stroke that often remains unrecognised. Screening has been suggested but there is very little evidence concerning the uptake of screening in the elderly population at risk, nor of the optimal method of screening in a general practice setting

AIM

To compare the uptake and effectiveness of two methods of screening for atrial fibrillation in general practice--systematic nurse-led screening and prompted opportunistic case finding.

DESIGN OF STUDY

Randomised controlled trial.

SETTING

Patients aged 65 to 100 years (n = 3,001) from four general practices within the MRC general practice framework.

METHOD

Each of the four study practices were selected from one quartile, after ranking all framework practices according to the small area standardised mortality ratio of the geographical area served. Patients were randomised either to nurse-led screening or to prompted opportunistic casefinding. The proportion of patients assessed and the proportion found to have atrial fibrillation were compared. The sensitivity and specificity of clinical assessment of pulse are also reported.

RESULTS

Substantially more patients had their pulse assessed through systematic screening by invitation (1,099/1,499 [73%]) than through opportunistic case finding (439/1,502 [29%], difference = 44%, 95% confidence interval [CI] = 41% to 47%). Atrial fibrillation was detected in 67 (4.5%) and 19 (1.3%) patients respectively (difference = 3.2%, 95% CI= 2.0 to 4.4). Invitation to nurse-led screening achieved significantly higher assessment rates than case finding in all practices; however, the proportion of patients assessed in the case-finding arm varied markedly between practices (range = 8% to 52%). The number needed to screen to identify one additional patient with atrial fibrillation was 31 (95% CI = 23 to 50). The proportion of screened patients with atrial fibrillation receiving anticoagulation treatment was 25%, although in the majority (53/65 [82%]) atrial fibrillation had been previously recorded somewhere on their medical record. If the nurse used any irregularity of the pulse as the screening criterion, the sensitivity of screening was 91% and the specificity was 74%; sensitivity fell to 54% but specificity increased to 98% if the criterion used was continuous irregularity.

CONCLUSIONS

Nurse-led screening for atrial fibrillation in UK general practice is both feasible and effective and will identify a substantial number of patients who could benefit from antithrombotic therapy. Although the majority of patients detected at first screening could be identified by careful scrutiny of medical records, review of record summaries was insufficient in the practices involved in this study and screening may be a more cost-effective option.

A review of anticoagulation with warfarin in patients with nonvalvular atrial fibrillation

BACKGROUND

Warfarin therapy has proved safe and effective in a number of randomized controlled trials of stroke prophylaxis in patients with nonvalvular atrial fibrillation (NVAF), reducing the risk of stroke in these patients by two thirds. However, participants in the clinical trials were carefully selected and younger than patients in actual clinical practice.

OBJECTIVE

This analysis sought to determine whether the results of clinical trials in patients with NV can be extrapolated to the general population seen in clinical practice.

METHODS

A MEDLINE search from 1966 to the present was used to identify observational trials of anticoagulation in patients with NVAF that addressed warfarin use, anticoagulation control, efficacy, and complications. The search terms used were atrial fibrillation and anticoagulation.

RESULTS

Although warfarin prophylaxis against stroke in patients with NVAF appeared to be as well tolerated and effective in clinical practice as in clinical trials, it was generally underused, particularly in the elderly. Anticoagulation control was not as good in clinical practice as in clinical trials, although the rates of stroke and major bleeding were comparable.

CONCLUSIONS

Judicious use of warfarin, tailored to individual stroke risk, seems to be a reasonable policy. Warfarin therapy increases quality-adjusted survival in patients at high risk for stroke, and it is recommended for medium-risk patients unless their risk of bleeding is high or their quality of life while taking warfarin would be poor. Patients at a low risk for stroke will have equivalent health outcomes and incur lower costs if treated with aspirin. Despite the increased risk of hemorrhage in elderly patients, the net benefit of warfarin therapy is greater in this age group because of the higher risk of stroke. Active involvement of patients and their caregivers in an anticoagulation service setting may improve outcomes of anticoagulation therapy.

Trends in the prevalence and management of atrial fibrillation in general practice in England and Wales, 1994-1998: analysis of data from the general practice research database

OBJECTIVE

To determine the prevalence of atrial fibrillation in England and Wales, and examine trends in its treatment with warfarin and aspirin between 1994 and 1998.

DESIGN

Analysis of data from the general practice research database.

SETTING

England and Wales.

PATIENTS

1.4 million patients registered with 211 general practices.

MAIN OUTCOME MEASURES

Age and sex specific prevalence rates of atrial fibrillation; percentage of patients with atrial fibrillation treated with oral anticoagulants or aspirin.

RESULTS

The prevalence of atrial fibrillation in 1998 was 12.1/1000 in men and 12.7/1000 in women. Prevalence increased from less than 1/1000 in under 35 year olds to over 100/1000 in those aged 85 years and over. There was a 22% increase in the age standardised prevalence of atrial fibrillation in men and a 14% increase in women between 1994 and 1998. The percentage of patients prescribed oral anticoagulants increased from 20% to 34% in men and from 17% to 25% in women. The percentage of men with atrial fibrillation prescribed aspirin increased from 26% to 36%, and the percentage of women increased from 24% to 36%. Applying the age and sex specific prevalence and treatment rates to the population gives an estimate of around 650 000 cases of atrial fibrillation in England and Wales. The greatest number of cases occurs in the 75-84 year old age group.

CONCLUSIONS

The number of patients in the community with identified atrial fibrillation is increasing. There has also been a pronounced increase in the percentage of patients with atrial fibrillation prescribed oral anticoagulants or aspirin.

Anticoagulation management in primary care: a trial-based economic evaluation

The demand for anticoagulation management is increasing because of a widening of the indications of treatment. A primary care clinic using near-patient testing and computer decision support software is one model of care to meet this increased demand. The study aimed to determine the cost and cost-effectiveness of primary care-based anticoagulation management in comparison with 'traditional' hospital care-based provision by means of a cost-effectiveness analysis using data from a Birmingham-based multicentre randomized controlled trial. The costs per patient per year in primary care were pound170 [95% confidence interval (CI) pound149-190] vs. pound69 (95% CI pound57-81). Sensitivity analysis demonstrated that the cost in primary care could be reduced to under pound100 per patient per year under plausible changes in the variables. Primary care provides similar levels of control to secondary care for patients on anticoagulation therapy. There is an increased cost of managing patients in primary care and at no point did primary care become a lower cost option than secondary care. Local decision-makers need to assess the increased cost of primary care anticoagulation management in terms of the potential reductions in high-cost serious adverse events.

Use of antithrombotic measures for stroke prevention in atrial fibrillation

OBJECTIVE

To evaluate appropriateness of antithrombotic use to prevent stroke in atrial fibrillation.

DESIGN, PATIENTS

344 patients with atrial fibrillation, stratified by age, were assessed clinically for contraindications to anticoagulation and stroke risk. The use of warfarin and aspirin was compared with recommendations for anticoagulation derived from pooled clinical trial data.

RESULTS

Low risk of stroke was seen in 47 (14%) patients, moderate risk in 213 (62%), and high risk in 84 (24%) patients included in the sample (mean (SD) age 68.4 (17.2) years, 42% men). The proportion of patients requiring anticoagulation varied from 258/344 (75%) to 72/344 (21%) depending upon criteria used, of whom 86/258 (33%) and 36/72 (50%) were receiving warfarin, respectively. Warfarin or aspirin were not being used in 124/297 (42%) patients with moderate to high risk, whereas anticoagulation was being undertaken in 13/47 (27%) patients at low risk of stroke. Antithrombotic use (warfarin or aspirin) was significantly less common in patients over 75 years of age, regardless of absence of contraindications and eligibility according to various criteria (p < 0.001).

CONCLUSIONS

A clear need for anticoagulation using clinical criteria existed in about 25% of patients in atrial fibrillation presenting to medical clinics who were at high risk of stroke. Of these, only 50% of eligible patients were being anticoagulated. Appropriate anticoagulation needs to be based on risk assessment rather than age. Consensus is therefore needed on appropriate antithrombotic use in clinical practice.

Primary prevention of arterial thromboembolism in non-rheumatic atrial fibrillation in primary care: randomised controlled trial comparing two intensities of coumarin with aspirin

OBJECTIVE

To investigate the effectiveness of aspirin and coumarin in preventing thromboembolism in patients with non-rheumatic atrial fibrillation in general practice.

DESIGN

Randomised controlled trial.

PARTICIPANTS

729 patients aged >/=60 years with atrial fibrillation, recruited in general practice, who had no established indication for coumarin. Mean age was 75 years and mean follow up 2. 7 years.

SETTING

Primary care in the Netherlands.

INTERVENTIONS

Patients eligible for standard intensity coumarin (international normalised ratio 2.5-3.5) were randomly assigned to standard anticoagulation, very low intensity coumarin (international normalised ratio 1.1-1.6), or aspirin (150 mg/day) (stratum 1). Patients ineligible for standard anticoagulation were randomly assigned to low anticoagulation or aspirin (stratum 2).

MAIN OUTCOME MEASURES

Stroke, systemic embolism, major haemorrhage, and vascular death.

RESULTS

108 primary events occurred (annual event rate 5.5%), including 13 major haemorrhages (0.7% a year). The hazard ratio was 0.91 (0.61 to 1.36) for low anticoagulation versus aspirin and 0.78 (0.34 to 1.81) for standard anticoagulation versus aspirin. Non-vascular death was less common in the low anticoagulation group than in the aspirin group (0.41, 0.20 to 0.82). There was no significant difference between the treatment groups in bleeding incidence. High systolic and low diastolic blood pressure and age were independent prognostic factors.

CONCLUSION

In a general practice population (without established indications for coumarin) neither low nor standard intensity anticoagulation is better than aspirin in preventing primary outcome events. Aspirin may therefore be the first choice in patients with atrial fibrillation in general practice.

Risk assessment and anticoagulation for primary stroke prevention in atrial fibrillation

BACKGROUND AND PURPOSE

Risk assessment before anticoagulation is important for effective stroke prevention in atrial fibrillation (AF).

METHODS

A study was undertaken in patients with AF to investigate the contribution of clinical and echocardiography (ECHO) criteria to treatment decisions on anticoagulation. Patients were stratified by age and stroke risk; contraindications to anticoagulation and warfarin use were assessed. The value of ECHO in treatment decisions, effect of age, and existing anticoagulation practice were evaluated.

RESULTS

The mean+/-SD age of 234 patients was 67.1+/-11.8 years, and 122 (52%) were women. Clinical risk factors were present in 74 of 80 patients (92%) aged >75 years compared with 99 of 154 patients (64%) </=75 years (P<0.01). ECHO risk was identified in 94 of 154 patients (61%) </=75 years, 16 (17%) of whom had no clinical risk factors. ECHO risk was present in 71 patients (88%) >75 years of age, and was associated with clinical risk factors in all patients. Eligibility for anticoagulation was seen in 72 of 154 (47%) to 105 of 154 (68%) patients aged </=75 years, depending on the criteria used, and in 66 of 80 patients (83%) >75 years, regardless of criteria used (P<0.01). Warfarin was being used in 55 of 105 patients (51%) </=75 years and 8 of 66 patients (12%) >75 years (P<0.001). Anticoagulation was being undertaken in 7 of 49 patients (14%) </=75 years despite no clinical or ECHO risks.

CONCLUSIONS

Accurate assessments of eligibility and appropriateness of anticoagulation in AF can be made on clinical criteria alone, especially in older people. The value of ECHO in treatment decisions is limited to patients </=75 years of age with no clinical risk factors.

A community survey of patients with atrial fibrillation: associated disabilities and treatment preferences

BACKGROUND

Anticoagulants are effective in preventing stroke in those with atrial fibrillation, but most patients remain untreated.

AIM

To investigate the prevalence of disability, cognitive impairment, and problems with compliance in a representative sample of the elderly with atrial fibrillation, and to determine whether they would want treatment and how they would like services to be arranged.

METHOD

In a survey of a random sample of 4843 elderly subjects, those with atrial fibrillation were identified using electrocardiograms. Views on treatment were obtained using a structured interview. Disability was assessed using the Office of Population Censuses and Surveys Disability Scale and cognitive status using the Mini Mental State Examination. General practitioners were asked, via questionnaire, for their views on each subject's compliance.

RESULTS

Two hundred and seven elderly people with atrial fibrillation were identified. Almost all subjects expressed a willingness to undertake treatment to prevent stroke and preferred blood testing performed outside of hospital. Disability (82.7%), cognitive impairment (25.7%), and problems with compliance (25.0%) were common, but the prevalence of these difficulties was not substantially different from the general elderly population, and in many cases they could be overcome (e.g. only 10% of subjects had problems with compliance and no-one who could help them to comply).

CONCLUSIONS

Most elderly people with atrial fibrillation would accept treatment to prevent stroke. Disability, cognitive impairment, and problems with compliance may make it difficult to treat this patient group. An increase in the use of anticoagulants should be accompanied by the development of services appropriate to this frail population.

Prevalence of atrial fibrillation and eligibility for anticoagulants in the community

BACKGROUND

Anticoagulants are effective in the prevention of stroke in atrial fibrillation and flutter (AF). We aimed to find out the prevalence of AF in the UK and to estimate the proportion of patients with AF who might benefit from anticoagulation.

METHODS

We screened with electrocardiography a random sample of 4843 people from the community aged 65 years and older for AF. Participants with AF had further investigations to identify risk factors for stroke and contraindications to anticoagulants. We used three sets of criteria to assess risk and eligibility for anticoagulation.

FINDINGS

228 (4.7%) participants had AF. According to analyses derived from risk stratifications based on the Stroke Prevention in Atrial Fibrillation (SPAF) study 61% of these patients would have benefited from anticoagulation, 49% according to pooled analysis of trial results, and 41% according to the inclusion criteria for the SPAF 3 study. Anticoagulants were used by 1114 (23%) of all patients and were least used among elderly women, who may be the most likely to benefit. Echocardiography would be useful to assess the need for anticoagulation only in patients younger than 75 years with no contraindications to treatment and no clinical risk factors for stroke.

INTERPRETATION

Anticoagulants seem to be underused and misdirected in treatment of AF, according to various criteria. Efforts to promote and support wider and more appropriate use of anticoagulants would seem to be justified, and should decrease the incidence of stroke amongst elderly patients.

Atrial fibrillation amongst the Indo-Asian general practice population. The West Birmingham Atrial Fibrillation Project

Whilst there are recognised ethnic differences in cardiovascular disease, with a higher prevalence of hypertension and complications such as stroke amongst black/Afro-Caribbean populations, and ischaemic heart disease being more prevalent amongst Indo-Asians, the literature describing the clinical epidemiology of atrial fibrillation (AF) in non-caucasian groups is scarce. To survey the clinical features and management amongst Indo-Asian patients with known AF, we studied patients from six general practices in the west of Birmingham. The six general practices had a combined practice population of 25051, from which, the Indo-Asian population was 14670. A total of 12 Indo-Asian patients (six male, six female; mean age, 67 years; range, 42 to 95 years) with known AF were identified, suggesting a prevalence of AF in Indo-Asians aged >50 years of 0.6%. Six patients had chronic AF, two had recent onset (defined as onset <six months) and four had paroxysmal AF. Five patients had a history of ischaemic heart disease, three had hypertension, seven had heart failure, two had alcohol excess, four had mitral valve disease, and one patient with paroxysmal AF had sick sinus syndrome. None could be classified as having lone AF. Only four patients were anticoagulated, but, of the remaining eight, who were not taking warfarin, six were taking aspirin. None of the patients had contraindications to warfarin, but one of the patients who was taking aspirin had poor compliance to warfarin. In this survey of a general practice Indo-Asian population of approximately 14670, we found 12 patients with known AF. More information on the clinical epidemiology of AF in non-caucasian groups is still needed and urgently required, in view of the public health implications of this common cardiac arrhythmia.

A warfarin induction regimen for out-patient anticoagulation in patients with atrial fibrillation

Currently available protocols for induction of warfarin anticoagulation employ initial doses of 10 mg and are best suited to in-patient use. However, with the increasing number of elderly patients with atrial fibrillation requiring anticoagulation, there is a need for a less intense regimen which could be used for out-patients. We have established such a regimen and report on its prospective evaluation in 3 7 patients referred for out-patient initiation of warfarin, and a non-randomized comparison with 37 in-patients, with similar diagnoses, commenced on a traditional warfarin protocol. After exclusion of five patients on amiodarone, all of whom experienced supratherapeutic International Normalized Ratio (INR) results, the new out-patient regimen, employing an initial 5 mg dose, resulted in a lower maximum INR during the first 21 d therapy (median 2.9 v 4.0; P = 0.0001) and fewer INRs >4.5 (2/36 v 9/33) compared to the traditional 10 mg regimen. Time to reach stable anticoagulation was similar with each regimen; however, the 5 mg regimen gave a more accurate prediction of maintenance dose (correlation coefficient for predicted versus actual maintenance dose, r = 0.985). In comparison to a traditional 10 mg protocol, the proposed 5 mg warfarin induction regimen proved both safer and more reliable for initiation of prophylactic anticoagulation in patients with atrial fibrillation.

Screening for atrial fibrillation in primary care

OBJECTIVE

To investigate a population of elderly people for atrial fibrillation and to determine how many of the cases identified might benefit from treatment with anticoagulants.

METHODS

From a practice of four primary care physicians, 1422 patients aged 65 years and over were identified, of whom 1207 (85% of the total population) underwent electrocardiographic screening to detect the presence of atrial fibrillation. Patients with the arrhythmia were further evaluated by echocardiography and interview, to stratify their risk of stroke based on echocardiographic and clinical risk factors, their perceived risk from anticoagulation, and their attitude towards this treatment. Their primary care physician was also interviewed to determine the factors influencing the prescription of anticoagulants.

RESULTS

The arrhythmia occurred in 65 patients (5.4% overall), its prevalence increasing markedly with age (2.3% in 65 to 69 years age group; 8.1% in those over 85). Warfarin was being prescribed to 21.4% of these patients, although the findings of the study indicate that a further 20% were eligible for this treatment. Symptoms suggestive of cardiac failure were common (32.1%) and coexisting pathology was often identified by cardiac ultrasound in these patients (left ventricular hypertrophy, 32.1%; impaired left ventricular contractility, 21.4%; left atrial dilation, 80.4%; mitral annular calcification, 42.9%; mitral stenosis, 7.1%; mitral regurgitation, 48.2%; aortic stenosis, 8.9%). In all but one case, the decision to anticoagulate was based on the clinical rather than the echocardiographic findings.

CONCLUSIONS

Individual risk-benefit assessment in elderly patients with atrial fibrillation suggests that almost half (41.4%) are eligible for full anticoagulation with warfarin, whereas presently only one fifth are receiving this treatment. The decision to anticoagulate can be made on clinical grounds in most cases. If these results are confirmed, a doubling of the current number of patients taking anticoagulants can be anticipated.

Warfarin use among patients with atrial fibrillation

BACKGROUND AND PURPOSE

Warfarin reduces the rate of stroke among patients with atrial fibrillation. We sought to determine warfarin use within a population sample of elderly patients with atrial fibrillation.

METHODS

The Connecticut Peer Review Organization conducted a chart review of Medicare patients aged > or = 65 years with a history of atrial fibrillation before a hospitalization during the first 6 months of 1994.

RESULTS

Among 488 patients (308 women; 457 white; 173 aged > or = 85 years), 38% (184/488) had a relative contraindication to anticoagulation (history of bleeding, dementia, alcohol use, falls, cancer, or the need for nonsteroidal anti-inflammatory drugs). Among the remaining patients (with known atrial fibrillation, but without a contraindication), only 38% (117/304) had been prescribed warfarin. Of those not prescribed warfarin, 63% (117/187) were also not taking aspirin. There were 272 patients with at least one additional vascular risk factor and no contraindication to anticoagulation. Among these patients at moderate to high risk for stroke, anticoagulation had been prescribed in 40% (109/272). Overal, among those not prescribed warfarin, 58% (95/163) were not taking aspirin. Patients admitted with a stroke were more likely to be significantly underanticoagulated (with international normalized ratio < 1.5) (43.5% versus 20.9% for those without stroke; P < .005). Anticoagulation was most effective for those with an international normalized ratio > or = 2.0.

CONCLUSIONS

Warfarin anticoagulation with atrial fibrillation, even among "ideal" candidates, appears dramatically underutilized. In addition, among those prescribed warfarin, patients are often undertreated. Increased warfarin use among patients with atrial fibrillation represents an excellent opportunity for stroke prevention in the elderly.

Evidence-based medicine and general practice

Evidence-based medicine (EBM) aids clinical decision making in all fields of medicine, including primary care. General practice is characterized by particular emphasis on the doctor-patient relationship and on biomedical, personal and contextual perspectives in diagnosis. Most evidence available to general practitioners (GPs) addresses only the bio-medical perspective and is often not directly applicable to primary care, as it derives from secondary or tertiary care. Emphasis on the biomedical domain and the randomized controlled trial (RCT) alone reflects a reductionist approach that fails to do justice to the philosophy of general practice. The art of medicine is founded on context, anecdote, patient stories of illness and personal experience, and we should continue to blend this with good quality and appropriate research findings in patient care.

Warfarin anticoagulation in primary care: a regional survey of present practice and clinicians' views

The demand for anticoagulation services is rising. Warfarin anticoagulation has been shown to reduce the risk of stroke in patients with non-valvular atrial fibrillation by 68%. This raises issues about how services are best organized to initiate and monitor anticoagulation in this potentially large group of patients. We report the results of a regional postal survey undertaken to describe the views of general practitioners and consultants regarding warfarin anticoagulation in light of this potentially high increase in demand.

A survey of atrial fibrillation in general practice: the West Birmingham Atrial Fibrillation Project

BACKGROUND

The management of atrial fibrillation (AF) has changed substantially in recent years, especially with a greater appreciation of the prophylactic role of antithrombotic therapy against stroke. There is therefore a need for further information on the prevalence of AF in Britain, the prevalence of (and contraindications to) anticoagulant treatment, and the factors that influence doctors' decisions in treating AF, including the investigation of patients with this arrhythmia.

AIM

To investigate the prevalence, clinical features and management of patients with AF in a general practice setting.

METHOD

Cross-sectional survey of patients using treatment prescriptions and clinical records in two general practices from the west of Birmingham (serving a patient population of 16,519) where 4522 subjects (27.4%) were aged > or = 50 years.

RESULTS

One hundred and eleven (2.4%) patients who were aged > or = 50 years were found to be in AF (42 males; mean age 76.6, SD 9.1); 77.5% were Caucasian, 2.7% Afro-Caribbean, 0.9% Asian, and 0.9% mixed race; in 20 cases there was no information on ethnicity. Of the AF patients, 5.4% were aged 50-60 years, 16.2% aged 61-70 years, 20.7% aged 71-75 years, 20.7% aged 76-80 years, 24.3% aged 81-85 years, and 12.6% aged > 85 years old, with female patients being significantly older than males. Eighty-one patients (73%) had chronic AF, while 30 patients (27%) had paroxysmal AF. The most common associated factors were hypertension (36.9%) and ischaemic heart disease (28.8%), with no obvious cause for AF in six patients. Cardiac failure was associated with AF in 34 patients (30.6%), and stroke had occurred in 29 patients (18%). Only 20 patients (18%) had had an echocardiogram, 26 (23.4%) a chest X-ray, and 58 (52.3%) thyroid function test. Only 30.6% had ever presented to hospital practice. Warfarin was prescribed to 40 patients (36%), with anticoagulation intensity monitoring by the general practitioner (GP) in three cases (7.5%), by a hospital clinic in 30 (75%), and by both GP and hospital in seven cases (17.5%). Of those not anticoagulated (n = 71), only 12 patients (16.9%) had contraindications to warfarin therapy. Patients treated with warfarin were younger than those who were not prescribed warfarin (71.3 versus 79.6 years, P < 0.001). Aspirin was being prescribed for 21 patients (18.9%), primarily for previous myocardial infarction. Only five patients (4.5%) had ever had attempted cardioversion.

CONCLUSION

Atrial fibrillation is a common arrhythmia in general practice, and is commonly associated with hypertension, ischaemic heart disease and heart failure. There is a suboptimal application of standard investigations and use of antithrombotic therapy or attempted cardioversion; and few patients have presented to hospital practice. Guidelines on the management of this common arrhythmia in general practice are required.

Anticoagulant treatment in primary health care in Finland

OBJECTIVE

To establish the prevalence of anticoagulant (AC) treatment, the indications, and the quality of care in primary health care.

DESIGN

A cross-sectional study, in which patients on AC treatment were identified from laboratory records. The main and second indications for AC treatment and the last value of the AC-test were taken from medical records.

SETTING

Eight Finnish health centres with a total population of 182091 inhabitants.

RESULTS

A total of 1255 patients on AC treatment were identified, 48% of them men. The mean age was 68.9 years. The age-adjusted prevalence of AC treatment was 0.65%. The commonest main indication was atrial fibrillation (38%). It was the main or second indication in 591 patients (age-adjusted prevalence 0.30%). The next commonest main indication was deep vein thrombosis (15%), followed by pulmonary embolism (8%). A total of 274 (22%) patients were anticoagulated for cerebral circulatory disturbances. 86% of the latest prothrombin time values fell within recommended ranges.

CONCLUSION

The prevalence of AC treatment in Finland seems to be high. The proportion of patients with atrial fibrillation is high, differing from the results in other countries. The monitoring of AC-treatment as the general practitioner's responsibility functions well. The quality of care is good, even in older age groups.

The risks and benefits of antithrombotic therapy in chronic atrial fibrillation

As the risks of adverse effects of warfarin and aspirin in certain patients with chronic atrial fibrillation are high, intervention with these agents should be targeted towards those who will derive most benefit. Clearer guidelines are emerging to identify those patients and to standardise current prescribing practices.

The science of perpetual change

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ABC of atrial fibrillation. Atrial fibrillation in general and hospital practice

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