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

A pilot randomized controlled trial of a decision support tool to improve the quality of communication and decision-making in individuals with atrial fibrillation

OBJECTIVES

To design a tool for nonvalvular atrial fibrillation (NVAF) to inform individuals of their individual stroke and bleeding risks, assist in clarifying priorities, and promote communication.

DESIGN

Clustered randomized controlled trial.

SETTING

Primary care clinics.

PARTICIPANTS

Individuals with NVAF (N = 135).

INTERVENTION

Completion of tool before regularly scheduled visit.

MEASUREMENTS

Primary outcomes included the 100-point informed and values clarity subscales of the decisional conflict scale (lower scores indicate individual is more informed and has greater clarity). Secondary outcomes included knowledge, patient-clinician communication, and change in treatment.

RESULTS

Sixty-nine individuals were enrolled in the intervention group and 66 in the control group. After their visit, intervention participants had lower scores on the informed (mean difference = -11.9, 95% confidence interval (CI) = -21.1 to -2.7) and values clarity subscales (mean difference = -14.6, 95% CI = -22.6 to -6.6). Greater proportions of intervention participants knew medications for reducing stroke risk (61% vs 31%, P < .001) and side effects (49% vs 37%, P = .07). Stroke (71% vs 12%) and bleeding risk (69% vs 20%) were discussed more frequently in the intervention than control group (P < .001). Five intervention participants expressed a preference for medication that was not concordant with their current treatment plan. There was no change in treatment plan in either group.

CONCLUSION

The tool was effective in improving perceived and actual knowledge and values clarity and in increasing physician-patient communication but did not change treatment.

Current approaches to anticoagulation for reducing risk of atrial fibrillation-related stroke

Stroke is a major cause of death and disability and, as such, is associated with a heavy socioeconomic burden. Atrial fibrillation (AF) is an independent risk factor for ischemic stroke, and AF-related stroke tends to be more severe and poses a higher risk of recurrence than non-AF-related stroke. Anticoagulant prophylaxis with warfarin is effective in preventing stroke in eligible patients with AF, but in real-world practice this agent, though inexpensive, is underutilized. Moreover, warfarin has notable drawbacks that result in suboptimal anticoagulation and, as a result, greater disease burden and higher costs. Newer oral antithrombotic drugs with a wide therapeutic window and no requirement for routine coagulation monitoring may be as efficacious as warfarin and, given the costs associated with managing warfarin therapy, they may also prove to be more cost effective.

Cost-effectiveness of apixaban compared with aspirin for stroke prevention in atrial fibrillation among patients unsuitable for warfarin

BACKGROUND

Compared with aspirin, apixaban reduces stroke risk in atrial fibrillation (AF) patients unsuitable for warfarin by 63% but does not increase major bleeding. We sought to determine the cost-effectiveness of apixaban versus aspirin.

METHODS AND RESULTS

Using the Apixaban versus Acetylsalicylic Acid to Prevent Stroke in Atrial Fibrillation Patients Who Have Failed or Are Unsuitable for Vitamin-K Antagonist Treatment (AVERROES) trial and other studies, we constructed a Markov model to evaluate the costs (2011US$), quality-adjusted life-years (QALYs), and incremental cost-effectiveness of apixaban versus aspirin from the Medicare perspective. Our base-case assumed a 70-year-old AF patient cohort with a CHADS(2) score=2 and a lower-risk of bleeding. We used a 1-month cycle-length and ran separate base-case analyses assuming a trial-length (1-year) and a longer-term (10-year) follow-up. Total costs/patient were $3454 and $1805 for apixaban and aspirin in the trial-length and $44 232 and $50 066 in the 10-year model. Corresponding QALYs were 0.96 and 0.96 in the trial-length and 6.87 and 6.51 in the 10-year model, making apixaban inferior in the first model but dominant in the latter. Conclusions were sensitive to baseline stroke rate in both models, and the monthly cost of major stroke, relative risk of stroke, and prior vitamin-K antagonist use in the life-time model. Probabilistic sensitivity analysis suggested apixaban would only be a cost-effective alternative (<$50 000/QALY) to aspirin 11% of the time in the trial-length model, but cost-effective or dominant 96.7% and 87.5% of iterations in the 10-year model.

CONCLUSIONS

In our trial-length model, apixaban was more costly and no more effective than aspirin; however, as follow-up was extended, apixaban became cost-effective and eventually dominant.

Cost-effectiveness of dabigatran versus genotype-guided management of warfarin therapy for stroke prevention in patients with atrial fibrillation

BACKGROUND

Dabigatran is associated with lower rate of stroke comparing to warfarin when anticoagulation control is sub-optimal. Genotype-guided warfarin dosing and management may improve patient-time in target range (TTR) and therefore affect the cost-effectiveness of dabigatran compared with warfain. We examined the cost-effectiveness of dabigatran versus warfarin therapy with genotype-guided management in patients with atrial fibrillation (AF).

METHODOLOGY/PRINCIPAL FINDINGS

A Markov model was designed to compare life-long economic and treatment outcomes of dabigatran (110 mg and 150 mg twice daily), warfarin usual anticoagulation care (usual AC) with mean TTR 64%, and genotype-guided anticoagulation care (genotype-guided AC) in a hypothetical cohort of AF patients aged 65 years old with CHADS(2) score 2. Model inputs were derived from literature. The genotype-guided AC was assumed to achieve TTR = 78.9%, adopting the reported TTR achieved by warfarin service with good anticoagulation control in literature. Outcome measure was incremental cost per quality-adjusted life-year (QALY) gained (ICER) from perspective of healthcare payers. In base-case analysis, dabigatran 150 mg gained higher QALYs than genotype-guided AC (10.065QALYs versus 9.554QALYs) at higher cost (USD92,684 versus USD85,627) with ICER = USD13,810. Dabigatran 110 mg and usual AC gained less QALYs but cost more than dabigatran 150 mg and genotype-guided AC, respectively. ICER of dabigatran 150 mg versus genotype-guided AC would be >USD50,000 (and genotype-guided AC would be most cost-effective) when TTR in genotype-guided AC was >77% and utility value of warfarin was the same or higher than that of dabigatran.

CONCLUSIONS/SIGNIFICANCE

The likelihood of genotype-guided anticoagulation service to be accepted as cost-effective would increase if the quality of life on warfarin and dabigatran therapy are compatible and genotype-guided service achieves high TTR (>77%).

Small bowel endoscopy: cost-effectiveness of the different approaches

Obscure gastrointestinal haemorrhage is defined the presence of overt or occult bleeding in the setting of a normal endoscopic examination of the upper and lower gastrointestinal tracts. While obscure bleeding is not common, the evaluation and management of these patients often incurs considerable expense. Potential options for small bowel evaluation include traditional radiographic studies, push enteroscopy, video capsule endoscopy, deep enteroscopy, tagged red blood cell scans, angiography, and enterography examinations with either computed tomography and/or magnetic resonance imaging. The decision regarding which modality to employ depends on the cost of the procedure, its effectiveness in rendering a diagnosis, and the potential for administration of therapy. This article will discuss determination of costs associated with technology for small bowel imaging, quality of life data associated with chronic GI haemorrhage, and available cost-effectiveness studies comparing the options for small bowel exploration.

Cost-effectiveness of clopidogrel plus aspirin for stroke prevention in patients with atrial fibrillation in whom warfarin is unsuitable

Guidelines for atrial fibrillation (AF) recommend clopidogrel plus aspirin as an alternative stroke prevention strategy in patients in whom warfarin is unsuitable. A Markov model was conducted from a Medicare prospective using data from the Atrial Fibrillation Clopidogrel Trial with Irbesartan for Prevention of Vascular Events-A (ACTIVE-A) trial and other published studies. Base-case analysis evaluated patients 65 years old with AF, a CHADS(2) (congestive heart failure, 1 point; hypertension defined as blood pressure consistently >140/90 mm Hg or antihypertension medication, 1 point; age ≥75 years, 1 point; diabetes mellitus, 1 point; previous stroke or transient ishemic attack, 2 points) score of 2, and a lower risk for major bleeding. Patients received clopidogrel 75 mg/day plus aspirin or aspirin alone. Patients were followed for up to 35 years. Outcomes included quality-adjusted life-years (QALYs), costs (in 2011 American dollars), and incremental cost-effectiveness ratios. Quality-adjusted life expectancy and costs were 9.37 QALYs and $88,751 with clopidogrel plus aspirin and 9.01 QALYs and $79,057 with aspirin alone. Incremental cost-effectiveness ratio for clopidogrel plus aspirin was $26,928/QALY. With 1-way sensitivity analysis using a willingness-to-pay threshold of $50,000/QALY, clopidogrel plus aspirin was no longer cost effective when the CHADS(2) score was ≤1, major bleeding risk with aspirin was ≥2.50%/patient-year, the relative risk decrease for ischemic stroke with clopidogrel plus aspirin versus aspirin alone was <25%, and the utility of being healthy with AF on combination therapy decreased to 0.95. Monte Carlo simulation demonstrated that clopidogrel plus aspirin was cost effective in 55% and 73% of 10,000 iterations assuming willingness-to-pay thresholds of $50,000 and $100,000/QALY. In conclusion, clopidogrel plus aspirin appears cost-effective compared to aspirin alone for stroke prevention in patients with AF with a CHADS(2) of ≥2 and a lower risk of bleeding.

Patient values and preferences in decision making for antithrombotic therapy: a systematic review: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Development of clinical practice guidelines involves making trade-offs between desirable and undesirable consequences of alternative management strategies. Although the relative value of health states to patients should provide the basis for these trade-offs, few guidelines have systematically summarized the relevant evidence. We conducted a systematic review relating to values and preferences of patients considering antithrombotic therapy.

METHODS

We included studies examining patient preferences for alternative approaches to antithrombotic prophylaxis and studies that examined, in the context of antithrombotic prophylaxis or treatment, how patients value alternative health states and experiences with treatment. We conducted a systematic search and compiled structured summaries of the results. Steps in the process that involved judgment were conducted in duplicate.

RESULTS

We identified 48 eligible studies. Sixteen dealt with atrial fibrillation, five with VTE, four with stroke or myocardial infarction prophylaxis, six with thrombolysis in acute stroke or myocardial infarction, and 17 with burden of antithrombotic treatment.

CONCLUSION

Patient values and preferences regarding thromboprophylaxis treatment appear to be highly variable. Participant responses may depend on their prior experience with the treatments or health outcomes considered as well as on the methods used for preference elicitation. It should be standard for clinical practice guidelines to conduct systematic reviews of patient values and preferences in the specific content area.

Cost-Effectiveness of Dabigatran for Stroke Prophylaxis in Atrial Fibrillation

Background—

Recent studies have investigated alternatives to warfarin for stroke prophylaxis in patients with atrial fibrillation (AF), but whether these alternatives are cost-effective is unknown.

Methods and Results—

On the basis of the results from Randomized Evaluation of Long Term Anticoagulation Therapy (RE-LY) and other trials, we developed a decision-analysis model to compare the cost and quality-adjusted survival of various antithrombotic therapies. We ran our Markov model in a hypothetical cohort of 70-year-old patients with AF using a cost-effectiveness threshold of $50 000/quality-adjusted life-year. We estimated the cost of dabigatran as US $9 a day. For a patient with an average risk of major hemorrhage (≈3%/y), the most cost-effective therapy depended on stroke risk. For patients with the lowest stroke rate (CHADS 2 stroke score of 0), only aspirin was cost-effective. For patients with a moderate stroke rate (CHADS 2 score of 1 or 2), warfarin was cost-effective unless the risk of hemorrhage was high or quality of international normalized ratio control was poor (time in the therapeutic range <57.1%). For patients with a high stroke risk (CHADS 2 stroke score ≥3), dabigatran 150 mg (twice daily) was cost-effective unless international normalized ratio control was excellent (time in the therapeutic range >72.6%). Neither dabigatran 110 mg nor dual therapy (aspirin and clopidogrel) was cost-effective.

Conclusions—

Dabigatran 150 mg (twice daily) was cost-effective in AF populations at high risk of hemorrhage or high risk of stroke unless international normalized ratio control with warfarin was excellent. Warfarin was cost-effective in moderate-risk AF populations unless international normalized ratio control was poor.

Cost effectiveness of warfarin versus aspirin in patients older than 75 years with atrial fibrillation

BACKGROUND AND PURPOSE

Oral anticoagulants are effective at reducing stroke compared with aspirin in atrial fibrillation patients older than 75 years. Although the benefits of reduced stroke risk outweigh the risks of bleeding, the cost effectiveness of warfarin in this patient population has not yet been established.

METHODS

An economic evaluation was conducted alongside a randomized, controlled trial; 973 patients ≥75 years of age with atrial fibrillation were recruited from primary care and randomly assigned to either take warfarin or aspirin. Follow-up was for a mean of 2.7 years. Costs of thrombotic and hemorrhagic events, anticoagulation clinic visits, and primary care utilization were determined. Clinical benefits were expressed in terms of a primary event avoided: fatal/nonfatal disabling stroke, intracranial hemorrhage, or systemic embolism. A cost-utility analysis was performed using quality-adjusted life years as the benefit measure.

RESULTS

Total costs over 4 years were lower in the warfarin group (difference, -£165; 95% CI, -£452-£89), primarily driven by the difference in primary event costs. The primary event rate over 4 years was lower in the warfarin group (0.049 versus 0.099), and the quality-adjusted life years score was higher (difference, 0.02; 95% CI, -0.07-0.11). With lower costs and a higher quality-adjusted life years score, warfarin is the dominant treatment, but the differences in both costs and effects are small.

CONCLUSIONS

Warfarin is cost-effective compared with aspirin in atrial fibrillation patients age ≥75 years. These data support the anticoagulant therapy option in this high-risk patient population. However, the small differences in costs and effects indicate the importance of exploring patient preferences.

Outcomes associated with deep enteroscopy

The purpose of this article is to describe the available data regarding the short- and long-term outcomes associated with deep enteroscopy. Deep enteroscopy can be defined as the use of an enteroscope to examine small bowel distal to the ligament of Treitz or proximal to the distal ileum. The term deep enteroscopy includes double-balloon, single-balloon, and spiral enteroscopy. Comparisons are made with push enteroscopy and intraoperative enteroscopy, the major therapeutic endoscopic options available to the gastroenterologist before the introduction of deep enteroscopy. The article concludes with a discussion regarding complications associated with deep enteroscopy and cost-effectiveness of management strategies for obscure bleeding. Proposed changes to the current algorithm for management of obscure bleeding are suggested.

[Does patient knowledge improve treatment outcome?]

Non-compliance in patients is rarely provoked by intention or laziness. Thus, patients should not be the first to be blamed for lack of therapeutic success. Non-compliance from health care providers to supply patients with necessary information and skills, though, is an important cause of insufficient treatment outcomes. Patient knowledge can improve health outcomes. But this knowledge must be evidence-based and relevant for the patient. In addition, knowledge must enable patients to assume an important part in disease control and treatment. Evaluation of patient information or self-management programmes should consider that knowledge is just one component of a complex intervention. Self-management programmes for type 1 diabetes or severe asthma are examples of where patient knowledge as part of a complex intervention may lead to substantially improved treatment outcomes. Disease-unspecific self-management programmes like the expert patient programme do not lead to important changes of relevant outcome measures. Patients and consumers want to participate in medical decision-making. However, there is a lack of evidence-based patient information for most indications. Informed decision-making by patients may lead to intelligent non-compliance and worsening of treatment outcome according to conventional assessment criteria. Direct-to-consumer advertising (DTCA) hits a public that lacks competencies in critical health literacy. Critical health literacy which combines the concept of evidence-based medicine and health literacy should be integrated into existing school curricula.

Cost-effectiveness analysis of management strategies for obscure GI bleeding

BACKGROUND AND AIMS

Of patients who are seen with GI hemorrhage, approximately 5% will have a small-bowel source. Management of these patients entails considerable expense. We performed a decision analysis to explore the optimal management strategy for obscure GI hemorrhage.

METHODS

We used a cost-effectiveness analysis to compare no therapy (reference arm) to 5 competing modalities for a 50-year-old patient with obscure overt bleeding: (1) push enteroscopy, (2) intraoperative enteroscopy, (3) angiography, (4) initial anterograde double-balloon enteroscopy (DBE) followed by retrograde DBE if the patient had ongoing bleeding, and (5) small-bowel capsule endoscopy (CE) followed by DBE guided by the CE findings. The model included prevalence rates for small-bowel lesions, sensitivity for each intervention, and the probability of spontaneous bleeding cessation. We examined total costs and quality-adjusted life years (QALY) over a 1-year time period.

RESULTS

An initial DBE was the most cost-effective approach. The no-therapy arm cost $532 and was associated with 0.870 QALYs compared with $2407 and 0.956 QALYs for the DBE approach, which resulted in an incremental cost-effectiveness ratio of $20,833 per QALY gained. Compared to the DBE approach, an initial CE was more costly and less effective. The initial DBE arm resulted in an 86% bleeding cessation rate compared to 76% for the CE arm and 59% for the no-therapy arm. The model results were robust to a wide range of sensitivity analyses.

LIMITATIONS

The short time horizon of the model, because of the lack of long-term data about the natural history of rebleeding from small-intestinal lesions.

CONCLUSIONS

An initial DBE is a cost-effective approach for patients with obscure bleeding. However, capsule-directed DBE may be associated with better long-term outcomes because of the potential for fewer complications and decreased utilization of endoscopic resources.

Values and preferences in oral anticoagulation in patients with atrial fibrillation, physicians' and patients' perspectives: protocol for a two-phase study

Background

Oral anticoagulation prevents strokes in patients with atrial fibrillation but, for reasons that remain unclear, less than 40% of all patients with atrial fibrillation receive warfarin. The literature postulates that patient and clinician preferences may explain this low utilization.

Design

The proposed research seeks to answer the following questions: i) When assessed systematically, do patients' and clinicians' preferences explain the utilization of warfarin to prevent strokes associated with atrial fibrillation? ii) To what extent do patients' and clinicians' treatment preferences differ? iii) What factors explain any differences that exist in treatment preferences between patients and clinicians? To answer these questions we will conduct a two-phase study of patient and clinician preferences for health states and treatments. In the first phase of this study we will conduct structured interviews to determine their treatment preferences for warfarin vs. aspirin to prevent strokes associated with atrial fibrillation using the probability trade-off technique. In the same interview, we will conduct preference-elicitation exercises using the feeling thermometer to identify the utilities that patients place on taking medication (warfarin and aspirin), and on having a mild stroke, a severe stroke, and a major bleed. In the second phase of the study we will convene focus groups of clinicians and patients to explore their answers to the exercises in the first phase.

Discussion

This is a study of patient and clinician preferences for health states and treatments. Because of its clinical importance and our previous work in this area, we will conduct our study in the clinical context of the decision to use antithrombotic agents to reduce the risk of stroke in patients with non-valvular chronic atrial fibrillation

Antithrombotic drug development for atrial fibrillation: proceedings, Washington, DC, July 25-27, 2005

In July 2005, leaders from academia, government, and industry convened in Washington, DC, to discuss key issues in the development of antithrombotic treatments for atrial fibrillation (AF). In addition to summarizing available data on the relative benefits and risks of currently available therapies in diverse clinical practice settings, we reviewed designs of ongoing trials and registries, focusing on areas of methodological controversy and uncertainty. Participants in this meeting described the growing burden of AF, summarized the data showing effectiveness of warfarin for prevention of stroke in AF, and noted that warfarin is both underused and poorly monitored and adjusted in general practice. There was consensus that there is an important unmet clinical need for better treatment of patients with AF at risk of stroke, including alternatives to warfarin that address its limitations. Comparative noninferiority trials to develop alternatives to warfarin must include warfarin management that is at least as good as that provided in historical trials. There was agreement that noninferiority trials can be done based on historical warfarin trials, and that placebo-controlled trials focused on patients not receiving warfarin in general practice can provide important information as well. Statistical principles for noninferiority in this setting were discussed, and a standard approach was proposed. A majority of clinical trial representatives suggested that large, simple, open-label trials would provide the most meaningful information relevant to future practice, but regulators cautioned that, in such a simple trial, one needs to ensure that the control group does at least as well as the historical controls for the noninferiority design to be interpretable. With this summary document, we hope to provide a helpful resource for future drug development for AF.

Incorporation of process preferences within the QALY framework: a study of alternative methods

OBJECTIVE

This article explores the implications of incorporating process preferences using time tradeoff and standard gamble methods to assess the benefits of health care.

METHODS

Data were derived from 2 sources: a randomized controlled trial of alternative palliative care treatments (plastic stents, thermal ablation, or brachytherapy) for esophageal cancer, and a valuation survey conducted among individuals who had previously undergone curative treatment for such cancer. Costs and quality-adjusted life years (QALYs) associated with different palliative treatments in terms of health outcome values were compared to costs and QALYs based on process values derived from 3 different treatment allocation methods: 1) receipt of most preferred treatment; 2) receipt of least preferred treatment; and 3) mean process values.

RESULTS

Process values produced a different number of QALYs and QALY gains compared to those derived from health outcome values. However, treatment recommendations based on process values corresponded with those based on health outcome values: brachytherapy was identified as the more cost-effective treatment in terms of the incremental cost-per-QALY ratio by both the standard health outcome values approach and methods based on process values. These findings were supported by probabilistic analysis using the net monetary benefit framework.

CONCLUSIONS

Estimation of process preferences provides additional information to policy makers in judgments over the cost-effectiveness of health care programs. These methods offer a promising alternative to standard cost-per-QALY estimation using health outcomes. However, further research examining the role of process preferences in decision making in other clinical applications appears warranted.

Professional centred shared decision making: patient decision aids in practice in primary care

BACKGROUND

Patient decision aids are increasingly regarded as important components of clinical practice that enable shared decision making (SDM) and evidence based patient choice. Despite broad acceptance of their value, there remains little evidence of their successful implementation in primary care settings.

METHODS

Health care practitioners from five general practice surgeries in northern England participated in focus group sessions around the themes of patient decision aids, patient and practitioner preferences and SDM. Participants included general practitioners (n = 19), practice nurses (n = 5) and auxiliary staff (n = 3). Transcripts were analysed using a framework approach.

RESULTS

We report a) practitioners' discussion of the current impetus towards sharing decisions and their perspectives on barriers to SDM, and b) the implementation of patient decision aids in practice and impediments such as lack of an evidence base and time available in consultations.

CONCLUSION

We demonstrate two orientations to sharing decisions: practitioner-centred and patient-centred with the former predominating. We argue that it is necessary to rethink the changes required in practice for the implementation of SDM.

A cautionary note on data sources for evidence-based clinical decisions: warfarin and stroke prevention

BACKGROUND

Stroke risk in nonvalvular atrial fibrillation can be reduced by warfarin or aspirin; the choice of therapy requires the assessment of risks and benefits. The authors compared methods of risk assessment and their implications for risk communication and treatment.

METHODS

Stroke risk was compared in 193 patients with atrial fibrillation using the Framingham equation; an atrial fibrillation-specific Framingham equation; the Congestive heart failure, Hypertension, Age, Diabetes and Stroke (CHADS(2)) score; the Stroke Prevention and Atrial Fibrillation (SPAF) scheme; and the Scottish Intercollegiate Guidelines Network (SIGN) guidelines. Treatment guidance from SIGN, a simple prediction rule, and a decision analytical approach was compared. In the latter, patients were classified as risk too low to benefit from warfarin if the risk of cerebral bleeding on warfarin approximated to, or exceeded, thromboembolic stroke risk reduction.

RESULTS

Framingham equations gave lower stroke risks overall than SIGN or SPAF. CHADS(2) was intermediate. Using SIGN, warfarin would be given to all 103 patients without a history of stroke/transient ischemic attack and for whom warfarin was not contraindicated but only to 73 patients using the simple prediction rule and 48 patients using the decision analysis.

CONCLUSION

Community-based cohorts give lower stroke risk estimates than CHADS(2); both give lower estimates than schemes from control groups from randomized controlled trials. Using community-derived risks would lead to fewer patients being treated with warfarin than guidance derived from randomized controlled trial controls, which may lead to many low-risk patients being treated with high-risk therapy. This raises the debate about appropriate sources of data for risk assessment to support risk communication and effective clinical decisions.

A patient decision aid to support shared decision-making on anti-thrombotic treatment of patients with atrial fibrillation: randomised controlled trial

OBJECTIVE

To determine the efficacy of a computerised decision aid in patients with atrial fibrillation making decisions on whether to take warfarin or aspirin therapy.

DESIGN

Two-armed open exploratory randomised controlled trial.

SETTING

Two research clinics deriving participants from general practices in Northeast England.

PARTICIPANTS

109 patients with atrial fibrillation aged over 60.

INTERVENTIONS

Computerised decision aid applied in shared decision-making clinic compared to evidence-based paper guidelines applied as direct advice.

MAIN OUTCOME MEASURES

Primary outcome measure was the decision conflict scale. Secondary outcome measures included anxiety, knowledge, decision-making preference, treatment decision, use of primary and secondary care services and health outcomes.

RESULTS

Decision conflict was lower in the computerised decision aid group immediately after the clinic; mean difference -0.18 (95% CI -0.34 to -0.01). Participants in this group not already on warfarin were much less likely to start warfarin than those in the guidelines arm (4/16, 25% compared to the guidelines group 15/16, 93.8%, RR 0.27, 95% CI 0.11 to 0.63).

CONCLUSIONS

Decision conflict was lower immediately following the use of a computerised decision aid in a shared decision-making consultation than immediately following direct doctor-led advice based on paper guidelines. Furthermore, participants in the computerised decision aid group were significantly much less likely to start warfarin than those in the guidelines arm. The results show that such an approach has a positive impact on decision conflict comparable to other studies of decision aids, but also reduces the uptake of a clinically effective treatment that may have important implications for health outcomes.

The cost of monitoring warfarin in patients with chronic atrial fibrillation in primary care in Sweden

Background

Warfarin is used for the prevention of stroke in chronic atrial fibrillation. The product has a narrow therapeutic index and to obtain treatment success, patients must be maintained within a given therapeutic range (International Normalised Ratio;INR). To ensure a wise allocation of health care resources, scrutiny of costs associated with various treatments is justified. The objective of this study was to estimate the health care cost of INR controls in patients on warfarin treatment with chronic atrial fibrillation in primary care in Sweden.

Methods

Data from various sources were applied in the analysis. Resource consumption was derived from two observational studies based on electronic patient records and two Delphi-panel studies performed in two and three rounds, respectively. Unit costs were taken from official databases and primary health care centres.

Results

The mean cost of one INR control was SEK 550. The mean costs of INR controls during the first three months, the first year and during the second year of treatment were SEK 6,811, SEK 16,244 and SEK 8,904 respectively.

Conclusion

INR controls of patients on warfarin treatment in primary care in Sweden represent a substantial cost to the health care provider and they are particularly costly when undertaken in home care. The cost may however be off-set by the reduced incidence of stroke.

Medical communication and technology: a video-based process study of the use of decision aids in primary care consultations

BACKGROUND

Much of the research on decision-making in health care has focused on consultation outcomes. Less is known about the process by which clinicians and patients come to a treatment decision. This study aimed to quantitatively describe the behaviour shown by doctors and patients during primary care consultations when three types of decision aids were used to promote treatment decision-making in a randomised controlled trial.

METHODS

A video-based study set in an efficacy trial which compared the use of paper-based guidelines (control) with two forms of computer-based decision aids (implicit and explicit versions of DARTS II). Treatment decision concerned warfarin anti-coagulation to reduce the risk of stroke in older patients with atrial fibrillation. Twenty nine consultations were video-recorded. A ten-minute 'slice' of the consultation was sampled for detailed content analysis using existing interaction analysis protocols for verbal behaviour and ethological techniques for non-verbal behaviour.

RESULTS

Median consultation times (quartiles) differed significantly depending on the technology used. Paper-based guidelines took 21 (19-26) minutes to work through compared to 31 (16-41) minutes for the implicit tool; and 44 (39-55) minutes for the explicit tool. In the ten minutes immediately preceding the decision point, GPs dominated the conversation, accounting for 64% (58-66%) of all utterances and this trend was similar across all three arms of the trial. Information-giving was the most frequent activity for both GPs and patients, although GPs did this at twice the rate compared to patients and at higher rates in consultations involving computerised decision aids. GPs' language was highly technically focused and just 7% of their conversation was socio-emotional in content; this was half the socio-emotional content shown by patients (15%). However, frequent head nodding and a close mirroring in the direction of eye-gaze suggested that both parties were active participants in the conversation

CONCLUSION

Irrespective of the arm of the trial, both patients' and GPs' behaviour showed that they were reciprocally engaged in these consultations. However, even in consultations aimed at promoting shared decision-making, GPs' were verbally dominant, and they worked primarily as information providers for patients. In addition, computer-based decision aids significantly prolonged the consultations, particularly the later phases. These data suggest that decision aids may not lead to more 'sharing' in treatment decision-making and that, in their current form, they may take too long to negotiate for use in routine primary care.

Patients or research subjects? A qualitative study of participation in a randomised controlled trial of a complex intervention

OBJECTIVE

To explore participants' understandings regarding treatment decisions, made within an efficacy randomised controlled trial (RCT) of decision-support tools.

METHODS

Qualitative study: interviews (audio-recorded) with participants. Participants were interviewed 3-5 days after using a decision-support tool (n=30) and again at 3 months (n=26). Transcripts were analysed using a constant comparative approach.

RESULTS

Participants' understandings were shaped by the ways in which they made sense of their participation. Participants made attributions about their trial identity that fell on a continuum. At one end we found participants who identified as 'experienced medical volunteers', and at the other those who identified as 'real patients'. In the participants' accounts, a trial identity of 'patient' accompanied an expectation that the decision-support tools offered a means of making treatment decisions. 'Volunteers', however, saw the interventions as tasks to be completed for the purposes of the trial team.

CONCLUSION

In our study, trial identity shaped participants' understandings regarding treatment decisions and all other aspects of the trial.

PRACTICE IMPLICATIONS

Different understandings regarding the appropriate response to trial tasks may affect behaviour and therefore outcomes in some trials. Further research is required to unravel the relationship between trial identities, understanding and behaviour.

Cost-effectiveness of self-managed versus physician-managed oral anticoagulation therapy

BACKGROUND

Patient self-management of long-term oral anticoagulation therapy is an effective strategy in a number of clinical situations, but it is currently not a funded option in the Canadian health care system. We sought to compare the incremental cost and health benefits of self-management with those of physician management from the perspective of the Canadian health care payer over a 5-year period.

METHODS

We developed a Bayesian Markov model comparing the costs and quality-adjusted life years (QALYs) accrued to patients receiving oral anticoagulation therapy through self-management or physician management for atrial fibrillation or for a mechanical heart valve. Five health states were defined: no events, minor hemorrhagic events, major hemorrhagic events, thrombotic events and death. Data from published literature were used for transition probabilities. Canadian 2003 costs were used, and utility estimates were obtained from various published sources.

RESULTS

Self-management resulted in 3.50 fewer thrombotic events, 0.78 fewer major hemorrhagic events and 0.12 fewer deaths per 100 patients than physician management. The average discounted incremental cost of self-management over physician management was found to be 989 dollars (95% confidence interval [CI] 310 dollars-1655 dollars) per patient and the incremental QALYs gained was 0.07 (95% CI 0.06-0.08). The cost-effectiveness of self-management was 14,129 dollars per QALY gained. There was a 95% chance that self-management would be cost-effective at a willingness to pay of 23,800 dollars per QALY. Results were robust in probabilistic and deterministic sensitivity analyses.

INTERPRETATION

This model suggests that self-management is a cost-effective strategy for those receiving long-term oral anticoagulation therapy for atrial fibrillation or for a mechanical heart valve.

Exploring challenges to TTO utilities: valuing states worse than dead

The conventional time trade off (TTO) method relies on fundamentally different procedures to assess states better than and worse than dead. Arbitrary transformation mechanisms are then applied to worse than dead scores in order to achieve symmetry with those rated as better than dead. We use a 'life profile' approach along with a ranking procedure in order to show how states rated worse than dead may be assessed in exactly the same manner as better than dead scores. We then explore a common issue associated with states worse than dead that has received some attention recently: maximal endurable time. Our results showed that, although the severe health state was commonly rated as worse than dead, there were relatively few respondents that exhibited MET preferences. We discuss the implications of our findings for the use of the TTO method in deriving values for states that are worse than dead.

Impact of a patient decision aid on care among patients with nonvalvular atrial fibrillation: a cluster randomized trial

BACKGROUND

Too few patients with nonvalvular atrial fibrillation (NVAF) receive appropriate antithrombotic therapy. We tested the short-term (primary outcome) and long-term (secondary outcome) effect of a patient decision aid on the appropriateness of antithrombotic therapy among patients with NVAF.

METHODS

We conducted a cluster randomized trial with blinded outcome assessment involving 434 NVAF patients from 102 community-based primary care practices. Patients in the intervention group received a self-administered booklet and audiotape decision aid tailored to their personal stroke risk profile. Patients in the control group received usual care. The primary outcome measure was change in antithrombotic therapy at 3 months. Appropriateness of therapy was defined using the American College of Chest Physicians (ACCP) recommendations.

RESULTS

The mean patient age was 72 years, and the median duration of NVAF was 5 years. In the control group, there was a 3% decrease over 3 months in the number of patients receiving therapy appropriate to their risk of stroke (40% [85/215] at baseline v. 37% [79/215] at 3 months). In the intervention group, the number of patients receiving therapy appropriate to their stroke risk increased by 9% (32% [69/219] at baseline v. 41% [89/219] at 3 months). Although the proportion of patients whose therapy met the ACCP treatment recommendations did not differ between study arms at baseline (p = 0.11) or 3 months (p = 0.44), there was a 12% absolute improvement in the number of patients receiving appropriate care in the intervention group compared with the control group at 3 months (p = 0.03). The beneficial effect of the decision aid did not persist (p = 0.44 for differences between study arms after 12 months).

INTERPRETATION

There was short-term improvement in the appropriateness of antithrombotic care among patients with NVAF who were exposed to a decision aid, but the improvement did not persist.

Are Cost Benefits of Anticoagulation for Stroke Prevention in Atrial Fibrillation Underestimated?

BACKGROUND AND PURPOSE

Stroke outcomes in patients with atrial fibrillation (AF) tend to be worse than those in patients without AF. The objective of this study was to evaluate whether the cost benefits of anticoagulation for stroke prevention in AF may currently be underestimated by existing economic models that do not distinguish between different stroke outcomes.

METHODS

A literature review was conducted in 3 areas: (1) studies comparing stroke outcomes in AF and non-AF patients; (2) studies providing long-term cost of stroke estimates; and (3) studies modeling the cost-effectiveness of anticoagulation with a vitamin K antagonist (eg, warfarin) in AF patients.

RESULTS

There is considerable evidence that stroke in AF patients has a worse outcome than in patients without AF, including higher mortality, severity, and recurrence rates, and greater functional impairment and dependency. Estimates of the long-term cost of stroke of different severities were between US 24,991 dollars for a mild stroke over 5 years and US 142,251 dollars for a major ischemic stroke over a lifetime (2004 prices). The cost of a severe ischemic stroke may typically be 3-times that of mild stroke. However, cost-effectiveness models for anticoagulation in patients with AF have used average (not AF-specific) cost-of-stroke data, and most have used stroke severity distributions derived from clinical trials, which may differ from those in clinical practice.

CONCLUSIONS

Existing economic models underestimate the cost benefits of anticoagulation for stroke prevention because they do not adjust for poorer outcomes associated with cardioembolic strokes.

A Bayesian approach to evaluating net clinical benefit allowed for parameter uncertainty

BACKGROUND AND OBJECTIVE

Although randomized controlled trials (RCTs) are conducted to establish whether novel interventions work on average in the patient population, there is a growing desire to move to a more individualized approach to evaluation. The potential benefits and harms of a treatment policy may differ between individuals. If these benefits and harms are not evaluated distinctly, and in a quantitative framework, transparency can be lost in the decision-making process.

METHODS

Glasziou and Irwig have outlined the concept of net clinical treatment benefit for identifying the patients for whom the potential benefits of treatment outweigh the possible side effects. This study revisits the decision whether to use warfarin to treat atrial fibrillation. In this analysis, RCT and various sorts of observational data are synthesized.

RESULTS

This reanalysis brings into question the conclusions of the original analysis on who would benefit from warfarin; however, caution is advised, due to limitations in the quality of life data available.

CONCLUSION

A fully realized Bayesian implementation of the model is presented. This provides a framework for including uncertainty related to the estimation of all model parameters, and permits both direct probability statements and credible intervals for specific patient groups to be expressed.

[Characteristics of oral anti-coagulation treatment in high-risk chronic auricular fibrillation]

OBJECTIVE

To calculate the prevalence of chronic auricular fibrillation (CAF), how much of it is considered high-risk (CAFhr) and the degree of coverage with oral anti-coagulation treatment (OAT).

DESIGN

Multi-centre descriptive study.

SETTING

9 health districts. The "Terres de l'Ebre" Primary Care Service.

PARTICIPANTS

Randomised sample of 375 patients with CAF, of whom 150 met the criteria of CAFh-r during 2002.

MAIN MEASUREMENTS

Profile of patients with CAFh-r; coverage with OAT; place of follow-up; presence of vascular complications, and the time relationships between the diagnosis of CAF, vascular complications and the start of OAT. All the INR determinations taken from the patients included in the study were used.

RESULTS

There was 2.2% prevalence of CAF (95% CI, 1.4-3.3). 40% of CAF had criteria of CAFh-r. 74.2% were treated with OAT. In 41.7% the diagnosis of CAF coincided with the incidence of some vascular complication. There were no differences between the overall results of the INR obtained in hospital and in PC. The expected efficacy of OAT for thromboembolism prevention in our high-risk sample was 61.12%.

CONCLUSIONS

40% of the CAF are high-risk. In over a third of patients OAT was indicated after a vascular complication linked to an unknown CAF. The INR between 2-3 is similar in PC centres and the corresponding haematology service.

Selecting Patients With Atrial Fibrillation for Anticoagulation

Background— The rate of stroke in atrial fibrillation (AF) depends on the presence of comorbid conditions and the use of antithrombotic therapy. Although adjusted-dose warfarin is superior to aspirin for reducing stroke in AF, the absolute risk reduction of warfarin depends on the stroke rate with aspirin. This prospective cohort study tested the predictive accuracy of 5 stroke risk stratification schemes.

Methods and Results— The study pooled individual data from 2580 participants with nonvalvular AF who were prescribed aspirin in a multicenter trial (Atrial Fibrillation, Aspirin, Anticoagulation I study [AFASAK-1], AFASAK-2, European Atrial Fibrillation Trial, Primary Prevention of Arterial Thromboembolism in patients with nonrheumatic Atrial Fibrillation in primary care study, and Stroke Prevention and Atrial Fibrillation [SPAF]-III high risk or SPAF-III low risk). There were 207 ischemic strokes during 4887 patient-years of aspirin therapy. All schemes predicted stroke better than chance, but the number of patients categorized as low and high risk varied substantially. AF patients with prior cerebral ischemia were classified as high risk by all 5 schemes and had 10.8 strokes per 100 patient-years. The CHADS 2 scheme (an acronym for Congestive heart failure, Hypertension, Age >75, Diabetes mellitus, and prior Stroke or transient ischemic attack) successfully identified primary prevention patients who were at high risk of stroke (5.3 strokes per 100 patient-years). In contrast, patients identified as high risk by other schemes had 3.0 to 4.2 strokes per 100 patient-years. Low-risk patients identified by all schemes had 0.5 to 1.4 strokes per 100 patient-years of therapy.

Conclusions— Patients with AF who have high and low rates of stroke when given aspirin can be reliably identified, allowing selection of antithrombotic prophylaxis to be individualized.

Patients' perspectives on taking warfarin: qualitative study in family practice

BACKGROUND

Despite the well-documented benefits of using warfarin to prevent stroke, physicians remain reluctant to initiate therapy, and especially so with the elderly owing to the higher risk of hemorrhage. Prior research suggests that patients are more accepting of the risk of bleeding than are physicians, although there have been few qualitative studies. The aim of this study was to employ qualitative methods to investigate the experience and perspective of individuals taking warfarin.

METHODS

We conducted face-to-face interviews with 21 older patients (12 male, 9 female) who had been taking warfarin for a minimum of six months. Participants were patients at a family practice clinic situated in a large, tertiary care teaching hospital. We used a semistructured interview guide with four main thematic areas: decision-making, knowledge/education, impact, and satisfaction. Data were analysed according to the principles of content analysis.

RESULTS AND DISCUSSION

Participants tended to have minimal input into the decision to initiate warfarin therapy, instead relying in great part on physicians' expertise. There appeared to be low retention of information received regarding the therapy; half the patients in our sample possessed only a superficial level of understanding of the risks and benefits. This notwithstanding, participants reported a high level of satisfaction with the care provided and a low level of impact on their day-to-day lives.

CONCLUSIONS

Minimal patient involvement in the initial decision and modest knowledge did not appear to diminish satisfaction with warfarin management. At the same time, care providers exert a tremendous influence on the initiation of warfarin therapy and should strive to incorporate patient preferences and expectations into the decision-making process.

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

BACKGROUND

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

DESIGN

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

The management of anticoagulants in the periendoscopic period for patients with atrial fibrillation: a decision analysis

PURPOSE

The management of patients who undergo endoscopy while being treated with warfarin is challenging. We used decision analysis to determine the preferred strategy to manage anticoagulants in the periendoscopic period.

METHODS

We designed a Markov model to estimate costs and quality-adjusted survival during a 10-year period in patients with nonvalvular atrial fibrillation undergoing screening colonoscopy. We compared six alternatives to the continue-warfarin strategy, which was to perform colonoscopy while the patient was taking full-dose warfarin. The hold-warfarin strategy was to stop warfarin 5 days before the colonoscopy. The repeat endoscopy strategy was to continue warfarin for a diagnostic colonoscopy, followed by a repeat procedure after cessation of warfarin if polypectomy was required. The dose-reduction strategy was to reduce the warfarin dose before colonoscopy. The low molecular weight heparin strategy was to administer subcutaneous low molecular weight heparin for 2 days before and 2 days after colonoscopy. The unfractionated heparin strategy was to administer intravenous unfractionated heparin for 2 days before and 2 days after the procedure. The vitamin K strategy was to hold warfarin for 4 days and to administer vitamin K if the international normalized ratio (INR) exceeded 2.0 the day before the procedure, or low molecular weight heparin if the INR was less than 1.5.

RESULTS

For screening colonoscopy, assuming that polyps would be removed in 35% of examinations, the hold-warfarin and dose-reduction arms were both cost-effective strategies. The hold-warfarin arm was most cost-effective if the likelihood of polypectomy exceeded 60%, or if there was a low risk of stroke despite atrial fibrillation. The continue-warfarin strategy was preferred if the probability of polypectomy was 1% or less.

CONCLUSION

Temporary warfarin cessation or halving the warfarin dose for several days before endoscopy was the preferred strategy for most patients. Periendoscopic heparin therapy was not cost-effective for patients with nonvalvular atrial fibrillation.

Benefits and harms associated with hormone replacement therapy: clinical decision analysis

OBJECTIVE

To evaluate harms and benefits associated with use of combined hormone replacement therapy (HRT) for five years in women with different baseline risks for breast cancer.

DESIGN

Probabilistic clinical decision analysis.

SETTING

Hypothetical population of white UK women aged 50 years with different baseline risks for breast cancer.

MAIN OUTCOME MEASURE

Gain or loss in quality adjusted life years (QALYs).

RESULTS

Women free of menopausal symptoms showed a net harm from HRT use, which increased for increasing baseline risk of breast cancer. Those with a baseline risk of 1.2% would expect a loss in QALYs of 0.4 months (- 0.03 QALYs, 95% credibility interval - 0.05 to - 0.01). The main analysis showed HRT to be on average beneficial in women with symptoms, with benefit decreasing with increasing baseline risk of breast cancer. The results were sensitive to the assumed value of quality of life with menopausal symptoms, therefore a contour plot was developed to show the probability of net harm for a range of different values and baseline risks.

CONCLUSIONS

HRT for primary prevention of chronic diseases in women without menopausal symptoms is unjustified. Perceived quality of life in women with symptoms should be taken into account when deciding on HRT. Thus, a decision analysis tailored to an individual woman is more appropriate in clinical practice than a population based approach.

Cost of care distribution in atrial fibrillation patients: the COCAF study

BACKGROUND

Atrial fibrillation (AF) currently represents a major economic burden for society. Very few studies have been performed to evaluate the cost of care for AF patients. This study is a large prospective survey designed to analyze the different cost drivers in the treatment of these patients. This survey, named Cost of Care in Atrial Fibrillation (COCAF), evaluated the cost of care for patients with AF treated by cardiologists in general office practice.

METHODS

A group of 671 patients was recruited by 82 cardiologists distributed in all regions of France. The mean age of the patients was 69 years, and 64% were male. The mean follow-up was 329 +/- 120 days. The costs of care were analyzed from the health care payer and the societal perspectives.

RESULTS

During the follow-up period, 21 patients (3.13%) died and 210 (31.3%) patients were hospitalized. The number of hospitalizations and deaths was significantly higher in the group of persistent or permanent AF (PEAF) patients, as compared to paroxysmal AF (PAAF) patients. Hospitalizations were much more frequent in the PEAF group (127) than in the PAAF group (83, P <.05). Deaths were also much more frequent in the PEAF group (17) as compared to the PAAF group (4, P <.001). From the societal perspective, the first cost driver was hospitalizations (52%), followed by drugs (23%), consultations (9%), further investigations (8%), loss of work (6%), and paramedical procedures (2%). In multivariate analysis the following parameters were significantly associated with higher costs: heart failure (P <.04), coronary artery disease (P <.001), use of class III antiarrhythmic drugs (P <.002), hypertension (P <.002) and metabolic disease (P <.001).

CONCLUSIONS

This prospective survey shows that hospitalizations represent the major cost driver in the treatment of AF patients. Outpatient care programs must be proposed to AF patients in order to avoid readmissions and to reduce the cost of treatment.

Effect of intensity of oral anticoagulation on stroke severity and mortality in atrial fibrillation

BACKGROUND

The incidence of stroke in patients with atrial fibrillation is greatly reduced by oral anticoagulation, with the full effect seen at international normalized ratio (INR) values of 2.0 or greater. The effect of the intensity of oral anticoagulation on the severity of atrial fibrillation-related stroke is not known but is central to the choice of the target INR.

METHODS

We studied incident ischemic strokes in a cohort of 13,559 patients with nonvalvular atrial fibrillation. Strokes were identified through hospitalization data bases and validated on the basis of medical records, which also provided information on the use of warfarin or aspirin, the INR at admission, and coexisting illnesses. The severity of stroke was graded according to a modified Rankin scale. Thirty-day mortality was ascertained from hospitalization and mortality files.

RESULTS

Of 596 ischemic strokes, 32 percent occurred during warfarin therapy, 27 percent during aspirin therapy, and 42 percent during neither type of therapy. Among patients who were taking warfarin, an INR of less than 2.0 at admission, as compared with an INR of 2.0 or greater, independently increased the odds of a severe stroke in a proportional-odds logistic-regression model (odds ratio, 1.9; 95 percent confidence interval, 1.1 to 3.4) across three severity categories and the risk of death within 30 days (hazard ratio, 3.4; 95 percent confidence interval, 1.1 to 10.1). An INR of 1.5 to 1.9 at admission was associated with a mortality rate similar to that for an INR of less than 1.5 (18 percent and 15 percent, respectively). The 30-day mortality rate among patients who were taking aspirin at the time of the stroke was similar to that among patients who were taking warfarin and who had an INR of less than 2.0.

CONCLUSIONS

Among patients with nonvalvular atrial fibrillation, anticoagulation that results in an INR of 2.0 or greater reduces not only the frequency of ischemic stroke but also its severity and the risk of death from stroke. Our findings provide further evidence against the use of lower INR target levels in patients with atrial fibrillation.

The influence of absolute cardiovascular risk, patient utilities, and costs on the decision to treat hypertension: a Markov decision analysis

OBJECTIVE

To estimate the effectiveness and cost-effectiveness of blood pressure-lowering treatment over a lifetime.

DESIGN

Markov decision analysis model comparing treatment and non-treatment of hypertension.

PARTICIPANTS

Hypothetical cohorts for 20 different strata of sex, age (30-79 years, in 10-year age bands), and cardiovascular risk (low and high risk).

MAIN OUTCOME MEASURES

Life expectancy, and incremental cost : effectiveness ratios for treatment and non-treatment strategies.

RESULTS

In terms of life expectancy, blood pressure treatment increased life expectancy in all age, sex, and risk strata, by between 1.6 and 10.3%, compared with a policy of non-treatment. In terms of cost-effectiveness, treatment was more effective, but also cost more than non-treatment for all age, sex, and risk strata except the oldest high-risk men and women. Incremental cost per quality-adjusted life year (QALY) among low-risk groups ranged from pound 1030 to pound 3304. Cost-effectiveness results for low-risk individuals were sensitive to the utility of receiving antihypertensive treatment. Treatment of high-risk individuals was highly cost-effective, such that it was the dominant strategy in the oldest age group, and resulted in incremental costs per QALY ranging from pound 34 to pound 265 in younger age groups.

CONCLUSIONS

Policy decisions about which patients to treat depend on whether a life-expectancy or cost-effectiveness perspective is taken. Treatment increases life expectancy in all strata of age, sex, and cardiovascular risk. However, younger individuals stand to gain proportionately more from blood pressure treatment than do the elderly. In terms of cost-effectiveness, patients at high risk of cardiovascular disease are a highly cost-effective group to treat. In patients at lower risk of cardiovascular disease, consideration should be given to issues of patient preference and cost.

Randomized trial evaluating the framing of cardiovascular risk and its impact on blood pressure control [ISRCTN87597585]

BACKGROUND

The format or frame in which the results of randomized trials are presented has been shown to influence health professional's self-reported practice. We sought to investigate the effect of framing cardiovascular risk as two different formats in a randomized trial.

METHODS

We recruited 457 patients aged between 60 and 79 years with high blood pressure from 20 family practices in Avon, UK. Patients were randomized to cardiovascular risk presented either as 1) an absolute risk level (AR) or as 2) the number needed to treat to prevent an adverse event (NNT). The main outcome measures were: 1) percentage of patients in each group with a five-year cardiovascular risk > or = 10%, 2) systolic and diastolic blood pressure, 3) intensity of prescribing of cardiovascular medication.

RESULTS

Presenting cardiovascular risk as either an AR or NNT had no impact reducing cardiovascular risk at 12 month follow up, adjusted odds ratio 1.53 (95%CI 0.76 to 3.08). There was no difference between the two groups in systolic (adjusted difference 0.97 mmHg, 95%CI -2.34 mmHg to 4.29 mmHg) or diastolic (adjusted difference 0.70 mmHg, 95%CI -1.05 mmHg to 2.45 mmHg) blood pressure. Intensity of prescribing of blood pressure lowering drugs was not significantly different between the two groups at six months follow up.

CONCLUSIONS

Presenting cardiovascular risk in clinical practice guidelines as either an AR or NNT had a similar influence on patient outcome and prescribing intensity. There is no difference in patient outcomes when these alternative formats of risk are used in clinical practice guidelines.

Meta-analysis and decision analysis bridge research and practice

Research synthesis methods provide meaningful quantitative data through systematic review of the research literature and translation of these findings into practice implications. Meta-analysis has been the gold standard for translation of research findings into practice. Decision analysis has emerged as an alternative to and extension of meta-analysis. Examples, contrasting the application of meta-analysis and decision analysis, are presented and discussed in relation to its relevance in providing clinical direction. The methods are points along the continuum of translating research findings into practice. Meta-analytic studies provide an essential foundation for estimating and assigning the probabilities used in decision analysis, whereas the outcomes of decision analysis provide data for estimating the cost effectiveness of different interventions or treatment options. Decision analysis can assist in bridging the research-practice gap. Nurse researchers are urged to collaborate with other disciplines that have used these methods to refine translation and use of research findings in practice.

A meta-analysis of quality-of-life estimates for stroke

BACKGROUND

Researchers performing cost-effectiveness analyses often incorporate quality-of-life (QOL) estimates.

OBJECTIVE

To aid analysts, we performed a meta-analysis to estimate quality of life for minor, moderate, and major stroke and assessed the relative importance of study design characteristics in predicting the quality of life of patients with stroke.

METHODS

Through a systematic search we identified 20 articles reporting 53 unique QOL weights for stroke. Each article was read and QOL weights and study characteristics were recorded. We used a hierarchical linear model (HLM) to perform a meta-regression. The model included severity of stroke, elicitation method, respondents, and QOL scale bounds as explanatory variables.

RESULTS

Severity of stroke (p < 0.0001) and the bounds of the scale (p = 0.0015) were significant predictors of quality of life, while the elicitation method and respondents were not. Pooling QOL weights using the HLM model, we estimated a quality of life of 0.52 for major stroke, 0.68 for moderate stroke, and 0.87 for minor stroke if the time trade-off method is used to assess quality of life from community members when the scale bounds range from death to perfect health.

CONCLUSIONS

We found no systematic difference in stroke QOL weights depending on elicitation method or respondents. However, quality of life is sensitive to the bounds of the scale. Because the pooled QOL estimates reported here are based on a comprehensive review of the QOL literature for stroke, they should be of great use to researchers performing cost-utility analyses of interventions designed to prevent or treat stroke, or where stroke is a possible side effect of therapy.

[Oral anticoagulation treatment in patients with non-valvular auricular fibrillation]

OBJECTIVES

To evaluate the knowledge, attitudes and difficulties of family doctors in the indication of oral anti-coagulation treatment (OCT) in patients with non-valvular auricular fibrillation (NVAF).

DESIGN

Transversal descriptive study.Setting. Area 11 of Madrid primary care.Participants. 250 doctors by simple randomised sampling.

MAIN MEASUREMENTS

After a pilot study at a health centre, mailing of a questionnaire with a subsequent re-mailing. This collected social and personal details, knowledge of the question, attitudes and difficulties.

RESULTS

157 (62.8%) replied; 91 were women (58.0%); mean age was 39 (SD, 6.0). 97 had reviewed the question recently (61.8%). 110 thought that the anti-aggregation criteria were clear (70.1%; CI, 62.2-77.0%), 107 that the oral anti-coagulation criteria were (68.2%; CI, 60.2-75.2%), 132 that the OCT risks were (84.1%; CI, 77.2-89.2%), and 74 that risk factors of cerebrovascular accident were clear (47.1%; CI, 39.2-55.2%). Initially 96 doctors gave anti-aggregants and referred to cardiology (61.1%; CI, 53.0-68.7%), and 29 began OCT (18.5%; CI, 12.9-25.6%). 134 thought that we avoided initiating OCT (85.3%; CI, 78.6-90.3%), giving as the main reasons the difficulty of monitoring and of requesting further tests, the risks involved and OCT not being up-to-date.

CONCLUSIONS

Most professionals have the criteria for OCT in NVAF clear, although they continue to avoid the initiation of OCT. The majority approach is to give anti-aggregants and refer to Cardiology, given the risk of the therapy and the difficulties involved in monitoring and requesting further tests.

Women's views of two interventions designed to assist in the prophylactic oophorectomy decision: a qualitative pilot evaluation

INTRODUCTION

A qualitative pilot evaluation of two different decision interventions for the prophylactic oophorectomy (PO) decision: a Decision Chart and a computerized clinical guidance programme (CGP) was undertaken. The Decision Chart, representing current practice in decision interventions, presents population-based information. The CGP elicits individual values to allow for quality-adjusted life years to be calculated and an explicit guidance statement is given. Prophylactic oophorectomy involves removal of the ovaries as an adjunct to hysterectomy to prevent ovarian cancer. The decision is complex because the operation can affect a number of long-term outcomes including breast cancer, coronary heart disease and osteoporosis.

METHODS

Both interventions were based on the evidence and were administered by a facilitator. The Decision Chart is a file, which progressively reveals information in the form of bar charts. The CGP is a decision-analysis based program integrating the results from a cluster of Markov cycle trees. The research evidence is incorporated with woman's individual risk factors, values and preferences. A purposive sample of 19 women awaiting hysterectomy used the decision interventions (10 CGP, nine Decision Chart). In-depth semi-structured interviews were undertaken. Interviews were transcribed and analysed to derive themes.

RESULTS

Reactions to the different decision interventions were mixed. Both were seen as clarifying the decision. Some women found some of the tasks difficult (e.g. rating health status). Some were surprised by the "individualized" guidance, which the CGP offered. The Decision Chart provided some with a sense of empowerment, although some found that it provided too much information.

CONCLUSIONS

Women were able to use both decision interventions. Both provided decision clarification. Problems were evident with both interventions, which give useful pointers for future development. These included the possibility for women to see how their individual risks of different outcomes are affected in the Decision Chart and enhanced explanation of the CGP tasks. Future design and evaluation of decision aids, will need to accommodate differences between patients in the desire for amount and type of information and level of involvement in the decision-making process.