How patients with atrial fibrillation value different health outcomes: a standard gamble study

BACKGROUND AND PURPOSE

The assessment of any health care intervention should consider both risks and benefits and take patients' preferences about these into account. The study reported in this paper aimed to elicit patient valuations of health states relevant to assessment of the prevention of stroke by warfarin anticoagulation therapy for patients with atrial fibrillation.

METHODS

A sample of patients over the age of 60 years with atrial fibrillation from three family practices in North-East England was interviewed. Their health state values were elicited using the standard gamble method for general practitioner (GP)-managed warfarin treatment, hospital-managed warfarin treatment, major bleed, mild stroke and severe stroke.

RESULTS

Of 180 patients, 69 (38%) agreed to participate, of whom 57 (83%) completed interviews. Median (mean) utility values were for GP-managed warfarin treatment 0.986 (0.948), hospital-managed warfarin treatment 0.984 (0.941), major bleed 0.880 (0.841), mild stroke 0.675 (0.641) and severe stroke 0 (0.189). There was wide variation in values between patients and the distributions were highly skewed.

CONCLUSIONS

The results are of value in applying decision analysis to groups of patients. They should be used with caution in reaching decisions about appropriate treatment for individual patients, but may provide a starting point for necessary further exploration of those patients' individual preferences.

Decision analysis and guidelines for anticoagulant therapy to prevent stroke in patients with atrial fibrillation

BACKGROUND

Clinical guidelines are needed on whether or not to use anticoagulant therapy to prevent stroke in patients with non-valvular atrial fibrillation. We did a Markov decision analysis to model decision-making with regard to warfarin treatment in patients with atrial fibrillation, and used the model to develop evaluative guidelines.

METHODS

The decision analysis involved a systematic literature review supplemented by patients' estimates of the quality of life associated with different states of health, secondary analysis of stroke-registry data, and estimation of service costs; it also incorporated a sensitivity analysis. The derived guidelines were subsequently applied to a cohort of patients with atrial fibrillation.

FINDINGS

We constructed decision tables for 12 age and sex groups. For most risk combinations, warfarin treatment would have decreased health-care costs and increased quality-of-life years, although the clinical decision was sensitive to patients' preferences and to the estimate of warfarin's effectiveness. 97% of women with atrial fibrillation older than 75 years, and 69% aged 65-74 would have been recommended for treatment; for men, the corresponding figures would have been 75% and 53%. With the upper quartile for the loss of quality of life associated with being on warfarin treatment (1.00), all but two of the 116 patients without contraindications would have been treated, whereas with the lower quartile (0.92), only 27 of 116 would have been treated.

INTERPRETATION

Decision analysis is useful in the incorporation of complex probabilistic data into informed decision-making, the identification of factors influencing such decisions, and the subsequent development of evaluative guidelines.

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.

Guidelines on anticoagulant treatment in atrial fibrillation in Great Britain: variation in content and implications for treatment

OBJECTIVE

To describe the content of guidelines on the use of anticoagulant treatment in patients with atrial fibrillation and the impact of variations in guidelines on treatment.

DESIGN

Postal survey of guidelines, semistructured interview with lead developers of guidelines, and application of guidelines to patient sample.

SUBJECTS

15 lead developers of the 20 guidelines identified in the postal survey were interviewed. 100 patients over 65 with atrial fibrillation to whom the guidelines were applied.

MAIN OUTCOME MEASURES

Evaluation of guidelines and the methods of dissemination, implementation, review, and evaluation; proportion of patients recommended for anticoagulant treatment by each guideline; and level of agreement between guidelines.

RESULTS

There was considerable variation in whether anticoagulant treatment was recommended for subjects (range 13% to 100%, kappa = 0.12). Guidelines varied greatly in advice on treatment by age, the use of echocardiography, and the target value or range of the international normalised ratio (8 of the 20 guidelines included values unlikely to be effective). Development was unsystematic; evidence based approaches were rarely used, 9 of the 15 lead developers had developed the guidelines themselves, and the 6 guidelines developed by groups relied on informal consensus. Methods to support effective dissemination, implementation, and evaluation were limited.

CONCLUSION

The widespread non-systematic production of guidelines has led to considerable variation with implications for the quality of care and clinical decision making. There is a need for a central, well funded programme of guideline development to ensure that valid guidelines are produced and disseminated.

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.

Peripheral mercury embolization occurring during arterial blood sampling

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