Survey of use of anticoagulation in patients with atrial fibrillation

Potential missed opportunities to prevent ischaemic stroke: prospective multicentre cohort study of atrial fibrillation-associated ischaemic stroke and TIA

OBJECTIVE

We report on: (1) the proportion of patients with known atrial fibrillation (AF); and (2) demographic, clinical or radiological differences between patients with known AF (and not treated) and patients with newly diagnosed AF, in a cohort of patients who presented with ischaemic stroke or transient ischaemic attack (TIA) not previously treated with anticoagulation.

DESIGN

We reviewed cross-sectional baseline demographic and clinical data from a prospective observational cohort study, (CROMIS-2).

SETTING

Patients were recruited from 79 hospital stroke centres throughout the UK and one centre in the Netherlands.

PARTICIPANTS

Patients were eligible if they were adults who presented with ischaemic stroke or TIA and AF and had not been previously treated with oral anticoagulation.

MAIN OUTCOME MEASURES

Proportion of patients with known AF before index ischaemic stroke or TIA from a cohort of patients who have not been previously treated with oral anticoagulation. Secondary analysis includes the comparison of CHA2DS2-VASc and HAS-BLED scores and other demographics and risk factors between those with newly diagnosed AF and those with previously known AF.

RESULTS

Of 1470 patients included in the analysis (mean age 76 years (SD 10)), 622 (42%) were female; 999 (68%) patients had newly diagnosed AF and 471 (32%) patients had known AF. Of the 471 patients with known AF, 68% had a strong indication for anticoagulation and 89% should have been considered for anticoagulation based upon CHA2DS2-VASc score. Patients with known AF were more likely to have a prior history of dementia (4% vs 2%, p=0.02) and had higher HAS-BLED scores (median 3 vs 2). CHA2DS2-VASc, other risk factors and demographics were similar.

CONCLUSIONS

About 1/3 of patients who present with stroke and have AF who have not been treated with oral anticoagulation have previously known AF. Of these patients, at least 68% were not adequately treated with oral anticoagulation.

TRIAL REGISTRATION NUMBER

NCT02513316.

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.

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.

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

OBJECTIVE

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

DESIGN

Qualitative study based on analysis of group interviews.

SETTING

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

PARTICIPANTS

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

RESULTS

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

CONCLUSIONS

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

Mortality and rate of stroke or embolism in atrial fibrillation during long-term follow-up in the embolism in left atrial thrombi (ELAT) study

BACKGROUND

Patients with atrial fibrillation (AF) have a higher mortality and risk of stroke/embolism than patients with sinus rhythm.

HYPOTHESIS

The aim of the study was to assess the association of clinical and echocardiographic characteristics with mortality and stroke/embolism and the use of antithrombotic medication in the year 2000 in patients who participated 1990-1995 in the Embolism in Left Atrial Thrombi (ELAT) study.

METHODS

The study included 409 outpatients with nonrheumatic AF (62 +/- 12 years, 36% women, 39% intermittent AF). Patients with thrombi received anticoagulation, patients without thrombi aspirin until follow-up in 1995; thereafter, anticoagulation according to clinical risk factors was recommended. Primary events were death and secondary events were stroke/embolism. All patients were contacted during the year 2000.

RESULTS

Mean follow-up was 102 months. Mortality was 4%/year; the cause of death was cardiac (n = 84), fatal stroke (n = 26), malignancy (n = 23), sepsis (n = 5), and unknown (n = 24). Multivariate analysis identified age (p < 0.0001), heart failure (p = 0.0013), and reduced left ventricular systolic function (p = 0.0353) as predictors of mortality. Stroke/embolism occurred in 83 patients, with a rate of 3%/year. Multivariate analysis identified age (p = 0.0006) and previous stroke (p = 0.0454) as predictors of stroke/embolism. In the year 2000, 51 (21%) of the 247 surviving patients received no antithrombotic medication, 88 received (36%) oral anticoagulants, 102 (41%) acetylsalicylic acid, and 6 (2%) low-molecular heparin.

CONCLUSIONS

Therapy for heart failure and oral anticoagulation in AF should be seriously considered, especially in elderly patients and in those with previous stroke.

Quality of blood pressure control and risk of cerebral bleeding in patients with oral anticoagulation

BACKGROUND

We assessed how many patients on long-term oral anticoagulation (OAC) (i) suffer from arterial hypertension (AH), (ii) are aware of AH, (iii) need improvement of their therapy and (iv) suffer from cerebral bleeding.

METHODS

Outpatients on long-term OAC were asked to measure blood pressure at least 4 times. Blood pressure was classified as normotensive if at least 75 % of all measurements were < 139/89 mm Hg; as mild/moderate AH if > 25 % of all measurements were 140 - 179 mm Hg systolic or 90 - 109 mm Hg diastolic; and as severe AH if > 25 % of all measurements were > 180 mm Hg systolic or > 110 mm Hg diastolic. Bleeding complications were registered.

RESULTS

Of the 235 patients (108 female, 67 +/- 12 years), 80 % suffered from AH. Severe AH was present in 5 %. Only 56 % were aware of suffering from AH. An improvement of antihypertensive therapy was needed in 64 %. Over 225 days, only one cerebral bleeding occurred. Blood pressure was normotensive in 30 % with known AH.

CONCLUSIONS

Blood pressure control seems better in OAC patients than in normals, if the patient is aware of AH. Patients with AH on OAC are not aware of AH in > 50 %. Repeated blood pressure measurements in OAC are recommended, even if patients are not aware of AH.

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.

Randomised trial of an integrated educational strategy to reduce investigation rates in young women with dysfunctional uterine bleeding

OBJECTIVES

To assess the effectiveness of an integrated educational strategy to change clinician behaviour and reduce the number of hysteroscopies and/or dilatation and curettages for women 40 years or less with dysfunctional uterine bleeding (DUB).

DESIGN

Randomised controlled trial with six-month follow-up.

SETTING

Public teaching hospital gynaecology units with 12,000-13,000 relevant procedures per year.

PARTICIPANTS

Six public gynaecology units made up of 62 gynaecologists or trainees allocated at random to intervention group - three, or control group - 3. Intervention An educational strategy that included dissemination of evidence-based guidelines via a problem-based interactive workshop facilitated by an opinion leader and a laminated algorithm and guidelines.

MAIN OUTCOME MEASURES

The number of hysteroscopies and/or dilatation and curettages performed for DUB on women 40 years or less, clinician behaviour change and perceived booking rates of the procedure.

RESULTS

At six months, there was no significant effect on the number of hysteroscopies and/or dilatation and curettages performed but there was an increase in evidence-based behaviour.

CONCLUSIONS

While the evidence-based educational strategy for the appropriate investigation of young women with DUB resulted in clinician behaviour change when applied to theoretical cases, it did not result in a reduction in hysteroscopy/D&C rates at six months.

Problems, interventions and complications in long-term oral anticoagulation therapy

BACKGROUND

If problems, interventions and complications occurring during oral anticoagulation (OAC) are related with age, indication for OAC, hypertension, diabetes, previous stroke, and number of additional drugs.

MATERIAL AND METHODS

Clinical characteristics, additional drugs, problems, interventions and complications of outpatients whose OAC was controlled between two years were registered. Potential gastrointestinal and urologic bleeding sources were eliminated prior to initiation of OAC. Five-hundred-seventy-nine patients (mean age 65 years, 44% female) were observed for 590 patient-years.

RESULTS

Medical problems occurred in 352/100 patient-years (% p-y), organisational problems in 276% p-y, interventions in 636% p-y and complications in 13.8% p-y. Patients >65 years had less organisational problems (254 vs. 302% p-y, p = 0.0092) and interventions (574 vs. 713% p-y, p = 0.0003) than patients < or =65 years. The 35 patients with heart valve prosthesis had more life-threatening and fatal complications (12% p-y) than the 360 patients with atrial fibrillation (1.0% p-y), 128 patients with venous thromboembolism or 56 patients with other indications (0.0% p-y, p = 0.0024). Problems, interventions and complications were not related with hypertension (n = 297), diabetes (n = 97) or previous stroke (n = 90). Patients with >3 additional drugs/day had a higher complication rate than patients with < or =3 drugs/day (21 vs. 8.7% p-y, p = 0.0238). Patients with complications had more headache (27 vs. 20% p-y, p = 0.0036), chest pain (45 vs. 27% p-y, p = 0.0150), abdominal pain (25 vs. 15% p-y, p = 0.0350) and pain in the limbs (55 vs. 42% p-y, p = 0.0044) than patients without complications.

CONCLUSIONS

By careful monitoring, eliminating potential bleeding sources, treating pain adequately and minimizing additional drugs the complications of OAC can be kept low.

Asymptomatic embolisation in non-valvular atrial fibrillation and its relationship to anticoagulation therapy

OBJECTIVE

A prospective study to determine the prevalence of embolic signals (ES) detected with transcranial Doppler ultrasound (TCD) in subjects with non-valvular atrial fibrillation (NVAF) who were and were not taking anticoagulants.

METHODS

Sixty-eight subjects with NVAF taking warfarin and sixty-three NVAF subjects not taking warfarin were recruited from the cardiology department. No patients had suffered a previous stroke or clinical systemic embolisation. Thirty subjects in sinus rhythm were recruited as controls. TCD recordings were performed bilaterally from the middle cerebral arteries for 1 h. In 126 subjects (96%) the recording was repeated 1 week later. All Doppler recordings were reviewed blindly by an observer for ES.

RESULTS

After one recording ES were detected in one warfarin NVAF subject (1.5%), four non-warfarin NVAF subjects (6.3%) and no sinus rhythm controls. Following both recordings ES were detected in one warfarin NVAF subject (1.5%) and seven non-warfarin NVAF subjects (11.9%) P = 0.017.

CONCLUSIONS

Asymptomatic ES can be detected in a minority of subjects with NVAF. These signals were significantly less common in NVAF subjects taking warfarin, and this is consistent with asymptomatic ES having clinical significance in this disease. TCD detection of ES may have application in patients with NVAF for risk stratification, and assessment of the efficacy of new anti-platelet and anti-thrombotic regimens in the condition. Further large prospective studies are required to determine whether ES predict stroke risk in this patient group.

[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.

Is warfarin really underused in patients with atrial fibrillation?

CONTEXT

There is agreement that warfarin decreases stroke risk in patients with atrial fibrillation (AF), but prior studies suggest that warfarin is markedly underused, for unclear reasons.

OBJECTIVE

To determine if warfarin is underused in the treatment of patients with atrial fibrillation.

DESIGN

Cross-sectional.

SETTING

Tertiary care VA hospital.

PATIENTS

All patients with a hospital or outpatient diagnosis of AF between 10/1/95 and 5/31/98.

DATA COLLECTION

One or more physician investigators reviewed pertinent records for each patient. When any of the 3 investigators thought warfarin might be indicated, the patient's primary care provider completed a survey regarding why warfarin was not used.

RESULTS

Of 1,289 AF patients, 844 (65%) had filled at least 1 warfarin prescription. Of the 445 remaining, 19 had died, 5 had inadequate medical records, and 54 received warfarin elsewhere, leaving 367 patients. Of these, 160 had no documented AF, 53 had only a history of AF, and 49 had only transient AF. Of the remaining 105 patients, 17 refused warfarin therapy and 72 had documented contraindications to warfarin use including bleeding risk or history, fall risk, alcohol abuse, or other compliance problems. The reasons for not using warfarin among the 16 patients remaining included provider oversight (n = 4) and various reasons suggesting provider knowledge deficits.

CONCLUSION

In contrast to prior studies that suggested that warfarin is markedly underused, we found that few patients with AF and no contraindication to anticoagulation were not receiving warfarin. We believe that differing study methodologies, including the use of physician review and provider survey, may explain our markedly different rate of warfarin underutilization, although local institutional factors cannot be excluded. The findings suggest that primary providers may be far more compliant with the standard of care for patients with atrial fibrillation than previously believed.

Stroke prevention in atrial fibrillation: physicians’ attitudes to anticoagulation in older people

The increased prevalence of atrial fibrillation (AF) in older people contributes to an increased risk of stroke. Although clear guidelines exist, there is considerable variation in physicians' approaches to the selection of patients appropriate for warfarin treatment as stroke prevention. We compared attitudes to the anticoagulation of elderly patients with AF, in a postal study of geriatricians and specialist physicians (general physicians with specialist interests in Cardiology, Gastroenterology, Diabetes and Endocrinology, Nephrology and Neurology). A structured questionnaire was mailed to all 108 consultant physicians and geriatricians in South East Wales. This explored their attitude to their patients' age and comorbidity when considering the benefits and risks of warfarin prophylaxis for AF. About 25/30 geriatricians (83%) and 43/78 specialist physicians (55%) responded; an overall response rate of 63%. About 94% of the respondents agreed that patients aged over 75 with atrial fibrillation were at a greater risk of stroke than younger patients. About 68% considered warfarin related bleeds more likely in this age group, despite which most thought that the benefits of warfarin outweighed the risks. In people aged above 75, only 13/25 (52%) geriatricians and 17/43 (40%) specialist physicians viewed lone AF (AF with no underlying risk factor) as an indication for anticoagulation. When considering the use of warfarin, geriatricians' appeared more likely to be influenced by coexisting problems such as disability, falls, cerebrovascular disease and limited life expectancy. Only a history of falls (96% geriatricians vs. 86% specialist physicians) and cerebrovascular disease (79% geriatricians vs. 51% specialist physicians) had a significant influence on prescribing practice (P<0.05, chi(2) test). There appears to be widespread uncertainty about the indications for warfarin as stroke prophylaxis, and ageist attitudes or a lack of conviction of benefit appear to be disadvantaging older people. Patients aged below 65 with lone AF who are at the lowest risk of embolic events are often considered for treatment, whilst the use of warfarin in 75-year-olds with lone AF who are at a moderately high risk of embolic events remains disappointing.

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.

Evaluation of risk factors for stroke/embolism and of complications due to anticoagulant therapy in atrial fibrillation

BACKGROUND AND PURPOSE

We sought to assess in outpatients with atrial fibrillation and oral anticoagulation (1) whether the complication rate is influenced by the presence of the risk factors age >65 years, arterial hypertension, diabetes, or previous stroke; (2) whether the complication rate is influenced by the number of additional drugs taken by patients; and (3) whether problems and interventions differ between patients with or without complications.

METHODS

- Clinical characteristics, drugs, problems, interventions, and complications were registered during 2 years.

RESULTS

- Three hundred sixty patients (mean age, 68 years; 43% female) were observed for 383 patient-years. Patients aged >65 years had more serious, life-threatening, or fatal complications (11% versus 5.3%/100 patient-years; P=0.0428) than younger patients. Patients with diabetes had more life-threatening and fatal complications (2.8% versus 0.6%/100 patient-years; P=0.0354) than patients without. The complication rate did not differ regarding the presence of previous stroke or hypertension. Patients who took </=3 drugs had fewer complications than patients who took more (4.3% versus 24.4%/100 patient-years; P=0.0041). Patients with complications complained more of chest (48% versus 28%/100 patient-years; P=0.0113) and abdominal pain (30% versus 13%/100 patient-years; P=0.0057), more frequently failed to keep appointments (134% versus 107%/100 patient-years; P=0.0321), had a higher tracking rate (134% versus 105%/100 patient-years; P=0.0272), and took more additional drugs (4.6 versus 3.5 drugs per day; P=0.0063) than patients with no complications.

CONCLUSIONS

- Patients with increased age or diabetes mellitus or those who take >3 drugs per day have an increased complication rate and thus need especially careful monitoring of oral anticoagulation, including adequate pain control.

Warfarin for stroke prevention still underused in atrial fibrillation: patterns of omission

BACKGROUND AND PURPOSE

The value of warfarin in preventing stroke in patients with chronic atrial fibrillation is well established. However, the prevalence of such treatment generally lags behind actual requirements. The aim of this study was to evaluate doctor- and/or patient-related demographic, clinical, and echocardiographic factors that influence decision for warfarin treatment.

METHODS

Between 1990 and 1998, 1027 patients were discharged with chronic or persistent atrial fibrillation. This population was composed of (1) patients with cardiac prosthetic valves (n=48), (2) those with increased bleeding risks (n=152), (3) physically or mentally handicapped patients (n=317), and (4) the remaining 510 patients, the main study group who were subjected to thorough statistical analysis for determining factors influencing warfarin use.

RESULTS

The respective rates of warfarin use on discharge in the 4 groups were 93.7%, 30.9%, 17.03%, and 59.4% (P=0.001); of the latter, an additional 28.7% were discharged on aspirin. In the main study group, warfarin treatment rates increased with each consecutive triennial period (29.7%, 53.6%, and 77.1%, respectively; P=0.001). Age >80 years, poor command of Hebrew, and being hospitalized in a given medical department emerged as independent variables negatively influencing warfarin use: P=0.0001, OR 0.30 (95% CI 0.17 to 0.55); P=0.02, OR 0.59 (95% CI 0.36 to 0.94); and P=0.0002, OR 0.26 (95% CI 0.12 to 0.52), respectively. In contrast, past history of stroke and availability of echocardiographic information, regardless of the findings, each increased warfarin use (P=0.03, OR 1.95 [95% CI 1.04 to 3.68], and P=0.0001, OR 3.52 [95% CI 2.16 to 5.72], respectively).

CONCLUSIONS

Old age, language difficulties, insufficient doctor alertness to warfarin benefit, and patient disability produced reluctance to treat. Warfarin use still lags behind requirements.

[Analysis of factors associated with anticoagulant treatment indication in chronic atrial fibrillation. Prospective study of 170 patients admitted at an internal medicine service]

BACKGROUND

Anticoagulant therapy reduces the risk of stroke among patients with chronic atrial fibrillation. The objective of this study was to evaluate the use of anticoagulant therapy and to analyze the factors associated with the indication of anticoagulants in patients with chronic atrial fibrillation.

PATIENTS AND METHODS

Prospective study of all patients with chronic atrial fibrillation admitted to our Department of Internal Medicine from February 1997 to September 1998. From each patient data related to the cause of atrial fibrillation, other associated vascular risk factors, use of anticoagulant and/or antiplatelet agents and contraindication to anticoagulants were recorded.

RESULTS

A total of 170 patients with chronic atrial fibrillation were studied. The mean age of patients was 77 years (range: 49-94). One hundred and four patients (61%) were older than 75 years. Atrial fibrillation was the main cause for admission only in 11 patients (6.5%). One hundred and sixty-seven patients (98%) had indication for receiving anticoagulant therapy; however, it was indicated in only 67 patients (39%). In other 68 patients (40%), antiplatelet agents were used. Patients over 75 years received anticoagulants less frequently (p < 0.0001). Factors associated with the prescription of anticoagulants in the bivariate analysis included: diabetes mellitus (p = 0.046), high cholesterol level (p = 0.023), age < or = 75 years old (p < 0.0001), history of previous embolic events (p = 0.001) and valvular atrial fibrillation (p < 0.0001). The multivariate analysis showed that only two factors were indeed associated with the prescription of anticoagulants: age < or = 75 years (OR: 6.15) and valvular atrial fibrillation (OR: 4.24).

CONCLUSIONS

Anticoagulant therapy is underused in patients with chronic atrial fibrillation, particularly in elderly patients.

Frequency of anticoagulation for atrial fibrillation and reasons for its non-use at a Veterans Affairs medical center

Randomized clinical trials have led to guidelines for anticoagulation in atrial fibrillation (AF). However, it is unclear how successfully these guidelines are being implemented in clinical practice and there is concern that anticoagulation is underused. Therefore, we examined the rate of anticoagulation in 998 patients with AF who attended a Veterans Affairs Medical Center over a 2-year period. Warfarin was prescribed for 504 patients (51%) and not prescribed for 494 patients (49%). Of these 494 patients, 446 had sufficient data for further assessment. Warfarin was judged not indicated in 200 because AF was transient or lone. Warfarin was indicated in 246 patients, 63% having > or =3 risk factors for thromboembolism. However, 184 of these patients also had at least 1 contraindication to anticoagulation. Thus, warfarin was prescribed to 67% of patients with AF in whom anticoagulation was indicated and to 89% of such patients in whom it was indicated and who had no contraindications. However, 25% of AF patients with strong indications for anticoagulation had concomitant contraindications, which precluded its use. We conclude that the use of warfarin for AF in this setting is higher than previously reported and approaching ideal levels. However, there remains a large, problematic subgroup of patients with AF in whom indications for and contra-indications to anticoagulation coexist.

Incident stroke after discharge from the hospital with a diagnosis of atrial fibrillation

PURPOSE

Atrial fibrillation is an important risk factor for stroke. We analyzed stroke risk over time in patients discharged from the hospital with a diagnosis of incident atrial fibrillation as compared with the risk of stroke in the Danish population.

SUBJECTS AND METHODS

In a random sample of half of the Danish population, we identified 13,625 men and 13,577 women, aged 50 to 89 years, with a hospital diagnosis of atrial fibrillation and no prior diagnosis of stroke during 1980 to 1993. Data on other medical conditions were also available from 1977 to 1993, but medication data were not available. Patients were followed from the diagnosis of atrial fibrillation until the first diagnosis of stroke (nonfatal or fatal cerebral ischemic infarct and cerebral hemorrhage), death, or the end of 1993. The risk of stroke in these patients was compared with the risk in the Danish population using Poisson regression modeling to estimate relative risks (RR) and 95% confidence intervals (CI).

RESULTS

For men with atrial fibrillation, the stroke rates increased by age, from 13 per 1,000 person-years in those ages 50 to 59 years, to 22 per 1,000 person-years in those ages 60 to 69 years, to 42 per 1,000 person-years in those ages 70 to 79 years, to 51 per 1,000 person-years in those ages 80 to 89 years. Age-specific stroke rates were similar in women with atrial fibrillation. Patients with a hospital diagnosis of atrial fibrillation had an increased risk of stroke (RR = 2.4; 95% CI, 2.3 to 2.5 in men and RR = 3.0; 95% CI, 2.9 to 3.2 in women) compared with the Danish population. Stroke risk was greatest during the first year after discharge and decreased thereafter. Hypertension, diabetes, and peripheral atherosclerosis were also associated with an increased risk of stroke among patients with atrial fibrillation. Ischemic heart disease and heart failure were risk factors in men only. There was no reduction in the risk of stroke from 1980 to 1993.

CONCLUSIONS

Men and women with atrial fibrillation are at a substantially increased risk of stroke, particularly in the first year after the diagnosis.

Variations in family physicians' and cardiologists' care for patients with heart failure

BACKGROUND

Improved understanding of the reasons for underuse of diagnostic tests and treatments for congestive heart failure (CHF) may be helpful for designing future interventions to improve quality of care.

METHODS

To determine differences between family physicians' and cardiologists' practice styles for diagnosis and treatment of CHF, a random sample of family physicians and cardiologists were surveyed with standardized case scenarios.

RESULTS

Survey respondents were 182 family physicians and 163 cardiologists. Family physicians were less likely than cardiologists to rate measurement of left ventricular ejection fraction as "very important" for patients with new CHF, less likely to order an echocardiogram or test for ischemia, and much less likely to identify diastolic dysfunction as a cause of CHF. Family physicians were more likely to prescribe digoxin when it was not indicated (diastolic dysfunction) and less likely to prescribe digoxin and an angiotensin-converting enzyme (ACE) inhibitor when they were indicated (moderately to severely reduced left ventricular ejection fraction). Family physicians expressed more concern over the risks of ACE inhibitors in patients with blood pressure of 100/70 mm Hg or serum creatinine of 2.0 mg/dL and were less likely to prescribe an ACE inhibitor in these settings. Family physicians overestimated the risks of warfarin use for atrial fibrillation and were therefore less likely to prescribe warfarin.

CONCLUSIONS

Family physicians appear to have less understanding of CHF pathophysiology (ie, systolic versus diastolic dysfunction) and how treatment differs according to the underlying disease process. Overestimation of the risk of ACE inhibitor and warfarin use may result in underprescribing these medications.

Stroke and atrial fibrillation: is stroke prevention treatment appropriate beforehand? SAFE I Study Investigators

OBJECTIVE

To undertake a pilot study before conducting a large European multicentre prospective study, to determine the proportion of patients with atrial fibrillation who were not receiving antithrombotic treatment before stroke onset, and their characteristics.

DESIGN AND PATIENTS

The stroke in atrial fibrillation ensemble (SAFE) I study was an observational study conducted in 213 patients with atrial fibrillation consecutively admitted in 1997 to three European centres for an acute stroke or transient ischaemic attack (TIA). It was determined whether they were receiving prior antithrombotic treatment.

RESULTS

Atrial fibrillation was known before stroke in 148 patients (69.5%). Of 213 patients, 34 (16.0%) were receiving anticoagulation treatment before stroke, but only six had an international normalised ratio between 2. 0 and 3.5; 65 (30.5%) were receiving antiplatelet treatment; and three (1.4%) were receiving both anticoagulation and antiplatelet treatment. Of 137 patients eligible for oral anticoagulation, 108 (78.8%) did not receive treatment. Of 142 patients eligible for any antithrombotic treatment, 62 (43.7%) were not treated. The logistic regression analysis, assuming anticoagulation treatment as a dependent variable, found digoxin treatment, absence of arterial hypertension, mitral stenosis, and cardioversion as independent factors. Assuming any antithrombotic treatment as a dependent variable, previously known atrial fibrillation, lower age, being a non-smoker, and absence of arterial hypertension were found to be independent factors.

CONCLUSION

More than half of the patients with atrial fibrillation admitted for acute stroke or TIA were not receiving any antithrombotic treatment beforehand. New onset atrial fibrillation and contraindications account for a minority of non-prescriptions; thus, other reasons should be identified to improve stroke prevention in the community.

Outpatient self-management of warfarin therapy: a pilot study

Self-testing and adjusting of warfarin dosages by patients is an evolving strategy for management of oral anticoagulation. We performed this open, prospective, 3-month pilot study to assess the feasibility of conducting a large, randomized trial comparing self-managed with physician-managed anticoagulation. Ten competent patients with planned anticoagulation for at least 3 months were provided education on warfarin therapy and trained to use an individualized warfarin nomogram. International normalized ratios (INRs) were determined weekly for 12 weeks and reported with warfarin dosages to the investigator for the first 8 weeks only. Eight patients elected to use a home monitor (ProTime) to measure INRs. Patients maintained 76.5% (range 50-91.7%) of INRs within the target range. In 119 dosage adjustment decisions, there were only 3 errors (2.5%). No bleeding or thrombotic complications occurred. To confirm concordance, initial and final INRs were measured concurrently by the ProTime monitor and laboratory. The mean absolute difference for 16 paired INR determinations was 0.33 (range 0.02-0.9). All patients expressed satisfaction and a desire to continue with self-management. This pilot study provides support for conducting a prospective, large-scale, randomized trial.

Age-related differences in management of heart disease: a study of cardiac medication use in an older cohort. Pacemaker Selection in the Elderly (PASE) Investigators

BACKGROUND

Previous studies have suggested suboptimal use of cardiac medications for secondary prevention after myocardial infarction (MI) and atrial fibrillation (AF), especially among older people.

OBJECTIVE

To determine whether patients older than 75 years are less likely than those aged 65 to 74 to be prescribed medications with evidence-based indications, including angiotensin-converting enzyme (ACE) inhibitors for left ventricular dysfunction (LVD) and/or diabetes mellitus (DM), aspirin and/or beta-blockers for those with a history of MI, and warfarin for chronic AF.

DESIGN

A retrospective cohort study.

SETTING

Twenty-nine hospitals, predominantly tertiary-care institutions.

PARTICIPANTS

A total of 407 patients randomized to ventricular or dual-chamber pacing from February 26, 1993, to September 30, 1994, in the Pacemaker Selection in the Elderly (PASE) trial.

MEASUREMENTS

A review of the patient's medical history and a physical exam at study enrollment, three follow-up timepoints, and a study closeout.

RESULTS

Patients older than 75 years with LVD and/or DM were less likely to be prescribed ACE inhibitors (OR = .56 (0.31-1.00)); patients older than 75 with a history of MI were less likely to be taking aspirin (OR = .43 (0.19-.95)), and patients older than 75 with AF were less likely to be prescribed warfarin (OR = .18 (0.05-.61)). Patients older than 75 years of age with any or all of the conditions studied were less likely to be prescribed indicated medications than those ages 65 to 74 (OR = .35 (0.18-.70)), after controlling for between-group differences in comorbidity, gender, and number of noncardiac medications.

CONCLUSION

Older age is a significant independent negative correlate of evidence-based cardiac medication use in this cohort. Causes for this finding need to be explored.

Oral anticoagulation in patients with atrial fibrillation: adherence with guidelines in an elderly cohort

PURPOSE

To determine adherence with practice guidelines in a population-based cohort of elderly persons aged 70 years or older with atrial fibrillation.

SUBJECTS AND METHODS

This was a cross-sectional analysis of a subgroup of participants in the Cardiovascular Health Study, a prospective observational study involving four communities in the United States. Subjects were participants with atrial fibrillation on electrocardiogram at one or more yearly examinations from 1993 to 1995. The outcome measure was self-reported use of warfarin in 1995.

RESULTS

In 1995, 172 (4.1%) participants had atrial fibrillation together with information regarding warfarin use and no preexisting indication for its use. Warfarin was used by 63 (37%) of these participants. Of the 109 participants not reporting warfarin use, 92 (84%) had at least one of the clinical risk factors (aside from age) associated with stroke in patients with atrial fibrillation. Among participants not taking warfarin, 47% were taking aspirin. Several characteristics were independently associated with warfarin use, including age [odds ratio (OR) = 0.6 per 5-year increment, 95% CI 0.5-0.9], a modified mini-mental examination score <85 points [OR = 0.3, 95% confidence interval (CI) 0.1-0.9], and among patients without prior stroke, female sex (OR = 0.5, 95% CI 0.2-1.0).

CONCLUSIONS

Despite widely publicized practice guidelines to treat patients who have atrial fibrillation with warfarin, most participants who had atrial fibrillation were at high risk for stroke but were not treated with warfarin. More studies are needed to determine why elderly patients with atrial fibrillation are not being treated with warfarin.

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.

Randomised trial of educational visits to enhance use of systematic reviews in 25 obstetric units

OBJECTIVE

To evaluate the effectiveness of an educational visit to help obstetricians and midwives select and use evidence from a Cochrane database containing 600 systematic reviews.

DESIGN

Randomised single blind controlled trial with obstetric units allocated to an educational visit or control group.

SETTING

25 of the 26 district general obstetric units in two former NHS regions.

SUBJECTS

The senior obstetrician and midwife from each intervention unit participated in educational visits. Clinical practices of all staff were assessed in 4508 pregnancies.

INTERVENTION

Single informal educational visit by a respected obstetrician including discussion of evidence based obstetrics, guidance on implementation, and donation of Cochrane database and other materials.

MAIN OUTCOME MEASURES

Rates of perineal suturing with polyglycolic acid, ventouse delivery, prophylactic antibiotics in caesarean section, and steroids in preterm delivery, before and 9 months after visits, and concordance of guidelines with review evidence for same marker practices before and after visits.

RESULTS

Rates varied greatly, but the overall baseline mean of 43% (986/2312) increased to 54% (1189/2196) 9 months later. Rates of ventouse delivery increased significantly in intervention units but not in control units; there was no difference between the two types of units in uptake of other practices. Pooling rates from all 25 units, use of antibiotics in caesarean section and use of polyglycolic acid sutures increased significantly over the period, but use of steroids in preterm delivery was unchanged. Labour ward guidelines seldom agreed with evidence at baseline; this hardly improved after visits. Educational visits cost pound860 each (at 1995 prices).

CONCLUSIONS

There was considerable uptake of evidence into practice in both control and intervention units between 1994 and 1995. Our educational visits added little to this, despite the informal setting, targeting of senior staff from two disciplines, and donation of educational materials. Further work is needed to define cost effective methods to enhance the uptake of evidence from systematic reviews and to clarify leadership and roles of senior obstetric staff in implementing the evidence.

The use of angiotensin-converting enzyme inhibitors in the treatment of heart failure in hospital practice

Several well-controlled trials in patients with heart failure have shown that the use of angiotensin-converting enzyme (ACE) inhibitors, in combination with a diuretic, causes a reduction in mortality and morbidity, which seems to be mainly due to a reduction in fatal and nonfatal cardiovascular events. Our aim was to determine whether 249 consecutive patients discharged from hospital with a primary diagnosis of heart failure were routinely being treated with an ACE inhibitor at an appropriate dose. At the time of admission to hospital, 91 (36.5%) were receiving a combination of a diuretic and an ACE inhibitor, 129 (51.8%) were receiving a diuretic alone, and 29 (11.6%) had not previously received either a diuretic or an ACE inhibitor. At the time of discharge from hospital all patients were on a diuretic and 144 (57.8%) were also receiving an ACE inhibitor. Although 41 patients (16.5%) had a relative or absolute contraindication for the use of an ACE inhibitor, 64 patients (25.7%) with no contraindication were not receiving an ACE inhibitor. Many of the patients who were prescribed an ACE inhibitor were given it at an inappropriate dose; only 24 patients (16.7%) were on the dose that was used in the clinical trials showing a reduction in mortality. These results show that in one in four patients admitted to hospital with heart failure who should be receiving an ACE inhibitor by the time of discharge, are not. The average age of these patients was 76 years. Whilst it has been shown that the benefit of ACE inhibitors does not appear to be age-related, most published studies have not included many patients over the age of 80. Specific studies looking at the effect of ACE inhibitors in elderly patients would be helpful, as well as studies to determine the optimum treatment regimen for this age group.

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.

Failure to prescribe warfarin to patients with nonrheumatic atrial fibrillation

OBJECTIVE

To determine how often warfarin was prescribed to patients with nonrheumatic atrial fibrillation in our community in 1992 when randomized trials had demonstrated that warfarin could prevent stroke with little increase in the rate of hemorrhage, and to determine whether warfarin was prescribed less frequently to older patients-the patients at highest risk of stroke but of most concern to physicians in terms of the safety of warfarin.

DESIGN

Cross-sectional study. Appropriateness of warfarin was classified for each patient based on the independent judgments of three physicians applying relevant evidence and guidelines.

SETTING

Two teaching hospitals and five community-based practices.

PATIENTS

Consecutive patients with nonrheumatic atrial fibrillation (n = 189).

MEASUREMENTS AND MAIN RESULTS

Warfarin was prescribed to 44 (23%) of the 189 patients. Warfarin was judged appropriate in 98 patients (52%), of whom 36 (37%) were prescribed warfarin. Warfarin was prescribed to 11 (14%) of 76 patients aged 75 years or older with hypertension, diabetes mellitus, or past stroke, the group at highest risk of stroke. In a multivariable logistic regression model controlling for appropriateness of warfarin and other patient characteristics, patients aged 75 years or older were less likely than younger patients to be treated with warfarin (odds ratio 0.25; 95% confidence interval 0.10, 0.65).

CONCLUSIONS

Warfarin was prescribed infrequently to these patients with nonrheumatic atrial fibrillation, especially the older patients and even the patients for whom warfarin was judged appropriate. These findings indicate a substantial opportunity to prevent stroke.

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

OBJECTIVE

To determine the opinions of selected physicians in our community about use of warfarin for patients with nonrheumatic atrial fibrillation, and to determine the relation of the physicians' opinions to their practices.

DESIGN

Survey of physicians, using eight hypothetical clinical vignettes to characterize physicians' opinions about use of warfarin in patients with nonrheumatic atrial fibrillation, according to patient age, risk of bleeding, and risk of stroke.

SETTING

Two teaching hospitals and five community-based practices.

PARTICIPANTS

Eighty physicians who cared for 189 consecutive patients with nonrheumatic atrial fibrillation.

MEASUREMENTS AND MAIN RESULTS

The survey response rate was 73%. Nearly all responding physicians (90%) recommended warfarin for at least one vignette. However, physicians recommended warfarin less often for vignettes depicting 85-year-old patients than for matched vignettes depicting 65-year-old patients (odds ratio [OR] 0.03; 95% confidence interval [CI] 0.01, 0.08), and less often for cases with specified risk factors for bleeding than for matched cases without the risk factors (OR 0.01; 95% CI 0.004, 0.03); warfarin was recommended more often for cases with a recent stroke than for matched cases without this history (OR 8.2; 95% CI 3.6, 18). In practice, warfarin was prescribed more often (p < or = .05) by physicians reporting good personal experience and by those who had favorable opinions about its use. However, even physicians with good experience and favorable opinions did not prescribe warfarin to half of their patents for whom warfarin was independently judged appropriate.

CONCLUSIONS

Physicians' opinions frequently opposed warfarin for older patients with nonrheumatic atrial fibrillation, and for those with bleeding risk factors. Physicians' opinions, as well as other barriers to warfarin therapy, most likely contribute to its infrequent prescription.

Fibrin D-dimer and beta-thromboglobulin as markers of thrombogenesis and platelet activation in atrial fibrillation. Effects of introducing ultra-low-dose warfarin and aspirin

BACKGROUND

Previous studies have demonstrated increased markers of thrombogenesis in patients with atrial fibrillation (AF), suggesting the presence of a hypercoagulable or prothrombotic state. The objective of this study was to determine the effects of introducing ultra-low-dose warfarin (1 mg), conventional warfarin, and aspirin. (300 mg) therapy on thrombogenesis and platelet activation in AF.

METHODS AND RESULTS

We measured sequential changes in plasma fibrin D-dimer (an index of thrombogenesis) and beta-thromboglobulin (beta-TG, a measure of platelet activation) in 51 patients with chronic AF before and at 2 and 6 weeks after randomization to either 1 mg warfarin or 300 mg aspirin (phase 1). Then all patients were started on conventional warfarin therapy (phase 2) with samples taken 2 and 6 weeks later. Pretreatment results were compared with those from 26 healthy control subjects in sinus rhythm. Baseline (pretreatment) beta-TG and D-dimer levels in patients with AF were elevated compared with those of control subjects (P < .001). In phase 1, there were no significant changes in median levels of fibrin D-dimer or beta-TG, despite warfarin 1 mg or aspirin 300 mg. With standard warfarin therapy (phase 2), there was a reduction in median beta-TG at 6 weeks (P = .025) and a sequential reduction in median D-dimer levels at 2 (P = .001) and 6 (P < .001) weeks compared with baseline levels.

CONCLUSIONS

Patients with AF have increased intravascular thrombogenesis and platelet activation compared with patients in sinus rhythm. Introduction of ultra-low-dose warfarin (1 mg) or aspirin 300 mg does not significantly alter these markers, although conventional warfarin therapy reduces beta-TG and fibrin D-dimer levels. This is consistent with the beneficial effect of full-dose warfarin in preventing stroke and thromboembolism in AF and suggests that ultra-low-dose warfarin and aspirin may not exert similar beneficial effects.

Canadian atrial fibrillation anticoagulation study: were the patients subsequently treated with warfarin? Canadian Atrial Fibrillation Anticoagulation Study Group

OBJECTIVE

To determine the effect of the results of clinical trials on the behaviour of patients and physicians, the authors ascertained the proportion of patients participating in the Canadian Atrial Fibrillation Anticoagulation (CAFA) study who started or continued warfarin therapy at the end of the study and identified factors affecting the decision to use or not use warfarin. The CAFA study was a double-blind, randomized, placebo-controlled, multicentre study to evaluate the efficacy of warfarin in preventing stroke among patients with nonrheumatic atrial fibrillation. Recruitment and follow-up were stopped early because two other similar studies had shown a decrease in the rate of stroke among patients treated with warfarin.

DESIGN

Mail survey 21 months after the end of the study.

PARTICIPANTS

The personal physicians of 336 patients who had participated in the CAFA study.

OUTCOME MEASURES

Type of antithrombotic therapy the patients had received since the CAFA study ended for patients who were not receiving warfarin, the reasons they were not.

RESULTS

Questionnaires concerning 254 (76%) of the patients who had participated in the study were returned. Since the end of the CAFA study, 153 (60%) of these patients had been treated continually with warfarin, 14 (6%) had been treated with warfarin but had subsequently stopped taking it, 59 (23%) had taken acetylsalicylic acid (ASA) continually, 5 (2%) had been taking ASA but had subsequently stopped taking it, and 23 (9%) had not taken either drug. The responding physicians stated that 58 (67%) of the patients who were not treated with warfarin did not wish to take the drug. The patients who had received warfarin during the CAFA trial were more likely to be treated with warfarin after the trial (75%) than were those who had received a placebo (56%) (p = 0.001). The probability of the patients' being treated with warfarin also depended on which study centre they had been treated in (p = 0.001).

CONCLUSIONS

Of the patients in the CAFA study for whom questionnaires were received, only 167 (66%) had been treated with warfarin after the end of the study. The patients were more likely to have been treated with warfarin after the study if they had received warfarin during the study. The positive results of clinical trials, on their own, are not enough to fully change the behaviour of patients and physicians.

The utilization of antithrombotic prophylaxis for atrial fibrillation in a geriatric rehabilitation hospital

OBJECTIVE

To determine the utilization of anticoagulant and antithrombotic agents in older patients with atrial fibrillation.

DESIGN

Retrospective chart review.

SETTING

A geriatric rehabilitation hospital.

PATIENTS

Subjects were 102 patients with atrial fibrillation as an intermittent or prevailing cardiac rhythm during a hospital admission in the 1993 fiscal year.

MEASUREMENTS

Age, sex, and mental status of the patients; duration and etiology of atrial fibrillation; presence of contraindications to anticoagulants or antithrombotic agents; and utilization of these agents in this population.

RESULTS

Of 102 older patients with atrial fibrillation at admission, only 51 were taking some form of anticoagulant or antithrombotic therapy proven effective for stroke prophylaxis (19 warfarin and 32 aspirin). Although 67 patients had relative contraindications to anticoagulation with warfarin, only 25 of the 35 with no contraindications were taking warfarin at the time of discharge. In addition, of the 43 patients with contraindications to warfarin but no contraindications to aspirin, only 28 were prescribed antithrombotic therapy.

CONCLUSIONS

Although anticoagulation or antithrombotic therapies for atrial fibrillation appear to be relatively widely used, there are still significant windows of opportunity for the improvement of clinician practice patterns and clinical outcomes in older patients.

Physician variation in the management of patients with atrial fibrillation

OBJECTIVE

To investigate variations in the management of patients with atrial fibrillation among consultant physicians.

DESIGN

Questionnaire survey.

SUBJECTS

Consultant physicians in England, Wales, and Scotland.

RESULTS

214 consultant physicians (88 cardiologists and 126 non-cardiologists) were surveyed between May and July 1994. Most physicians (47.7%) reported that they saw one to five patients with atrial fibrillation weekly. Some 52% of cardiologists and 40% of non-cardiologists considered that the main factor influencing their decision of whether or not to anticoagulate was the clinical history--that is, heart failure, valve disease, or stroke. When encountering a patient admitted acutely with new onset atrial fibrillation, significantly more cardiologists (66% v 52%, chi 2 = 6.89, P = 0.03) would immediately start anticoagulant treatment, most favouring intravenous heparin. Most physicians would also introduce antiarrhythmic treatment or digoxin, but more cardiologists would attempt immediate pharmacological (39% v 18% of non-cardiologists, P < 0.001) or later electrical (86% v 69%, chi 2 = 11.7, P = 0.003) cardioversion to sinus rhythm, while non-cardiologists tended to prefer "rate control" with digoxin. Although many physicians would not continue antiarrhythmic treatment post-cardioversion, more cardiologists than non-cardiologists would do so (the commonest choice being class III agents) (31% v 17%, P = 0.04). Fewer non-cardiologists would continue anticoagulant treatment post-cardioversion (27% v 69% of cardiologists, chi 2 = 39.8, P < 0.0001). When treating patients with atrial fibrillation, decisions about anticoagulation were usually related to the perceived relative risk of thromboembolism versus haemorrhage derived for each of six case management scenarios in the questionnaire. There was, however, general agreement between cardiologists and non-cardiologists in the use of antithrombotic treatment in the management of lone atrial fibrillation, paroxysmal atrial fibrillation, and patients with atrial fibrillation and mitral valve disease or thyrotoxicosis.

CONCLUSION

There is considerable variation in the management of atrial fibrillation, with more cardiologists than non-cardiologists considering cardioversion to sinus rhythm (and the use of antiarrhythmic and anticoagulant treatment post-cardioversion) and thrombo-prophylaxis with anticoagulation. Guidelines on the management of this common arrhythmia are clearly required.

Service provision and use of anticoagulants in atrial fibrillation

Several large trials have shown that the risk of stroke in patients with non-valvar atrial fibrillation is reduced by treatment with warfarin. Implementing this research evidence requires not only an understanding of the trials' results and of the changes that they imply for clinicians' treatment decisions but also an appreciation of the organisation, quantity, and quality of services required to support these changes. Understanding of these implications is crucial for developing services that allow changes in practice to produce reductions in stroke incidence while minimising the risks of treatment. This article considers the developments in service provision that will probably be required to support the changes in clinical practice suggested by the trials' results. These services will be provided largely by doctors, and their development has implications for doctors in both primary and secondary care.

Presentation and management of patients admitted with atrial fibrillation: a review of 291 cases in a regional hospital

Two hundred and ninety one patients admitted with atrial fibrillation through the emergency room of a regional hospital in the year 1993 were reviewed to evaluate the presenting features and in-hospital treatment of patients with symptomatic atrial fibrillation. The incidence of atrial fibrillation increased with age (mean age was 73 +/- 12 years) and the ratio of female to male was 1.8:1. The commonest presenting features were palpitation (42.3%), dyspnoea (38.1%) and heart failure (16.4%). The most frequently associated cardiac conditions were hypertension (28.9%), atherosclerotic cardiovascular disease (24.7%) and rheumatic heart disease (17.5%). Pulmonary diseases (18.6%), diabetes mellitus (12.7%) and thyrotoxicosis (6.2%) were the principal associated non-cardiac conditions. Thromboembolic complications were found in 15 patients at presentation (5.2%). Cardiac enzyme assessment was investigated in two thirds of the patients (68.1%), while thyroid function test (59.5%) and echocardiography (29.6%) were less commonly investigated. Digoxin was still the most popular drug used for ventricular rate control, and cardioversion was performed in only 6.9% of patients. Antithrombotic therapy was used in 5.8% of patients only although it was clinically indicated in more than half of the patients (52%). Contraindications of anticoagulation were found in 23 patients (7.9%), including a history of gastrointestinal or cerebrovascular bleeding, active bleeding, chronic renal failure and poor drug compliance. The mean hospital stay was 5 +/- 4 days, compared to a mean stay of 2.7 days for other medical patients. Fourteen patients (4.8%) died during hospitalisation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of age upon the induction and maintenance of anticoagulation with warfarin

We aimed to examine the effect of age upon the control of anticoagulation with warfarin in ordinary clinical practice, using a retrospective examination of routine anticoagulation clinic records from the University Hospital, Nottingham. Considerable over-anticoagulation (international normalisation ratio (INR) > 6.0) during induction occurred in 54 (11%) of 495 patients and was more likely in older patients (p < 0.05). Lesser degrees of over-anticoagulation during induction (INR > 4.0) were also more common in older patients, occurring in 58% of those aged 75 or above. Loading doses of warfarin were not reduced in older patients. INR in the maintenance phase rose with age (p < 0.001) despite lower maintenance doses of warfarin (p < 0.001). An INR > 6.0 in the maintenance phase was noted in 24 (3%) of 739 patients and again was more likely in older patients (p < 0.05). Patients using ambulance transport to the clinic were older than those who did not (p < 0.01) and those aged over 75 had shorter intervals between clinic visits (p < 0.01). We conclude that doctors using warfarin therapy do not take sufficient account of the increased sensitivity of older people to warfarin. Hospital anticoagulant policies need implementation and evaluation.

Use of warfarin in non-rheumatic atrial fibrillation: a commentary from general practice

Seven randomized trials published in the last six years have shown that warfarin reduces the risk of ischaemic strokes and death in patients with atrial fibrillation. The annual rates of major bleeding episodes in all these trials were low and, as a result, doctors in primary and secondary care are being encouraged to consider using warfarin for patients with atrial fibrillation unless there are obvious contraindications. However, the populations used in these studies were highly selected and rigorously monitored throughout the trial period to minimize the risk of bleeding in a way which probably could not be expected in routine primary care. Although the rates of major bleeding episodes were uniformly low, the rates of minor bleeding episodes were much higher and these could impact substantially on patients' views of the treatment and on the workload of the primary care team. Evidence is now at hand which allows the stratification of risk in patients with atrial fibrillation which should enable those who are at greatest risk to be considered for this form of treatment. Patients may develop risk factors over time which could render them unsuitable for continuation of warfarin therapy. The general practitioner is centrally placed to make the decision about initiating or continuing treatment or indeed stopping it. Several models for decision making in warfarin treatment from primary and secondary care are proposed.

Steroid induced osteoporosis: an opportunity for prevention?

OBJECTIVE

To determine the frequency with which osteoporosis prophylaxis is given to corticosteroid treated hospital inpatients.

METHODS

All patients receiving systemic corticosteroids in a large teaching hospital over a three month period were identified through routine prescription monitoring by hospital ward pharmacists. Coprescription of antiosteoporotic therapy was recorded, along with other relevant details such as steroid dose, actual, or intended duration of therapy, and indication for therapy.

RESULTS

Corticosteroids were prescribed to 214 patients over the study period, giving an average rate of 2.5 new prescriptions each day. Indications included: chest disease (n = 84; 39.2%), cancer (n = 17; 7.9%), inflammatory bowel disease (n = 16; 7.5%), rheumatoid arthritis/connective tissue disease (n = 16; 7.5%), and renal diseases (n = 7; 3.3%). One hundred and twelve patients (52.3%) were receiving short term steroid therapy (less than four months); 66 (37%) were receiving medium/long term steroid therapy (four months or more). In 36 cases (16.8%) the duration of therapy was unknown. Only 12 of the 214 patients (5.6%) received any form of osteoporosis prophylaxis. The prevalence of prophylaxis was similarly low in postmenopausal women (six of 93; 6.4%) and in patients receiving high dose long term steroid therapy (two of 25; 8%).

CONCLUSIONS

Systemic corticosteroids are used frequently in hospital practice for a wide range of indications, but few patients receive co-prescription of prophylaxis against osteoporosis. This is true even in high risk groups such as postmenopausal women and those on high dose long term steroid therapy. Identification of individuals by the mechanism used in this study provides an opportunity by which all corticosteroid treated patients could be detected and offered osteoporosis prophylaxis before serious loss of bone density has occurred.

Non-anticoagulation in atrial fibrillation

Atrial fibrillation (AF) is an important risk factor for stroke and anticoagulation is now indicated in many patients at increased risk. Studies however have shown that many patients at risk are not anticoagulated for reasons that are not well explored. We identified prospectively the reasons for non-anticoagulation in patients with AF in 94 consecutive hospital patients with cardiac or cerebrovascular disease who had AF. Patients with intermittent or lone AF and < 60 years were excluded n = 16. The remaining group had a mean age of 76 +/- 7 years with a mental test score of 7.4 +/- 2 (normal 10), 31 lived alone and they lived an average of 14 +/- 11 miles from the hospital laboratory. The reasons for non-anticoagulation overlapped and were: medical in 29: cognitive impairment/compliance in 32: and monitoring problems in 50. Anticoagulation for AF in the elderly is a complex enterprise which must take into account social and cognitive as well as medical issues.