Chest
Volume 141, Issue 2, Supplement, February 2012, Pages e1S-e23S
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Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physician Evidence-Based Clinical Practice Guidelines Online Only Articles
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

https://doi.org/10.1378/chest.11-2290Get rights and content

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.

Section snippets

Eligibility Criteria

We included studies that enrolled individuals potentially at risk of or having direct experience with conditions for which antithrombotic therapy may be indicated. We specifically included:

  • Studies that examined patient preferences for antithrombotic therapy vs no or alternative antithrombotic therapy, which includes receiving both treatment for thromboembolic disease and prophylaxis as defined previously

  • Studies that examined in the context of consideration of antithrombotic therapy how

Included Studies

Of 48 studies selected for inclusion, 16 focused on patients with atrial fibrillation,3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 five on patients with VTE,19, 20, 21, 22, 23 four on stroke or myocardial infarction prophylaxis,24, 25, 26, 27 six on thrombolysis in acute stroke or myocardial infarction,28, 29, 30, 31, 32, 33 and 17 on the burden of antithrombotic treatment.34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 Strategies used to elicit patient preferences

Summary of Findings

Three studies reported compelling findings of a higher disutility associated with stroke than with bleed. Alonso-Coello et al3 found that 19 of 96 participants (20%) were willing to accept > 35 additional bleeds on warfarin for 3% absolute risk reduction of stroke. For this 20%, the disutility associated with one stroke was equal to the disutility associated with 11.6 bleeding episodes. The median threshold that patient-participants were willing to accept was 10 bleeds for a 3% reduction in

Summary of Findings

These studies illustrate significant variability in elicited patient values and preferences regarding thrombosis prophylaxis and treatment. Locadia et al20 described extremely large between-patient variability with regard to participant willingness to accept warfarin treatment at varying thresholds of recurrent DVT. In another study by Locadia et al,21 the authors concluded that preferences stated in the form of health state utilities varied significantly across the three methods (Table 3).

Summary of Findings

A study by O'Meara et al23 found that no participant values and preferences were consistent with taking streptokinase, which differs from the findings of Lenert and Soetikno22 where the majority of participant preferences were consistent with use of streptokinase. Lenert and Soetikno22 explained these differences in results by arguing that their participants were better educated about the risks and benefits of DVT and its treatment, given that participants were presented with video and audio

Summary of Findings

The results of each of these studies illustrate how design features and participant characteristics may affect reported values and preferences. For example, in the 2001 study by Man-Son-Hing et al,26 enrollees in the Aspirin for Primary Prevention in the Low-risk Elderly (APPLE) pilot study would accept aspirin to gain a significantly smaller reduction in first-time stroke risk compared with those who did not enroll. This finding may indicate that individuals who enroll in trials may have

Summary of Findings

Results from Slot and Berge30 indicate that compared with individuals who have not experienced a given health event, those who have may associate a higher utility to that event. This factor may be important to consider when eliciting health state valuations for outcomes associated with antithrombotic treatment. These studies also illustrate that other factors such as age, sex, and living situation affect willingness to accept or reject treatment options (Table 6).

Summary of Findings

One could infer from the results of Heyland et al31 that many patients are extremely stroke averse (valuing avoiding stroke to a considerably greater extent than avoiding death). More likely, the results suggest that patients place a higher value on avoiding treatment-induced adverse (eg, hemorrhagic stroke) events than avoiding events prevented as a result of treatment. This latter interpretation is consistent with results from Fuller et al,5 who examined the relative aversion to thrombotic

Summary of Findings

Warfarin is, for most patients, associated with relatively limited impact on quality of life and the ability to carry out daily activities. Although some patients report anxiety or worry over the risks that they incur while taking warfarin therapy,35, 36, 37, 40, 41 they generally are satisfied with this treatment.39, 46 Other elements of burden that patients report include dietary modifications and the inconvenience associated with frequent blood monitoring. Duration of warfarin therapy was

Biases and Limitations Associated With Included Studies

There are a number of limitations associated with the included studies. Only three studies reported comprehension screening of potential participants,3, 4, 12 and two used only the data from participants with consistent results.6, 31 Le Sage and colleagues48 had research assistants walk through the survey with participants to ensure that the participants understood all the questions. It is possible that for those studies that did not pretest for comprehension, preferences elicited using methods

Discussion

We have carried out a systematic review of studies reporting patient values and preferences with regard to antithrombotic treatment. The results obtained through this review provide direction for guideline developers to base recommendations on patient values. In particular, this review highlights the apparently large variability in participant health state valuations and the factors, other than the impact of alternative management strategies on quantity and quality of life, that influence

Acknowledgments

Author contributions: As Topic Editor, Ms MacLean oversaw the development of this article, including the data analysis and findings contained herein.

Ms MacLean: served as Topic Editor.

Mr Mulla: served as a panelist.

Dr Jankowski: served as a panelist.

Dr Akl: served as a panelist.

Dr Vandvik: served as a panelist.

Mr Ebrahim: served as a panelist.

Ms McLeod: served as a panelist.

Ms Bhatnagar: served as a panelist.

Dr Guyatt: served as a panelist.

Financial/nonfinancial disclosures: In summary, the

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    Funding/Support: The Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines received support from the National Heart, Lung, and Blood Institute [R13 HL104758] and Bayer Schering Pharma AG. Support in the form of educational grants was also provided by Bristol-Myers Squibb; Pfizer, Inc; Canyon Pharmaceuticals; and sanofi-aventis US.

    Disclaimer: American College of Chest Physician guidelines are intended for general information only, are not medical advice, and do not replace professional medical care and physician advice, which always should be sought for any medical condition. The complete disclaimer for this guideline can be accessed at http://chestjournal.chestpubs.org/content/141/2_suppl/1S.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (http://www.chestpubs.org/site/misc/reprints.xhtml).

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    Ms MacLean is currently at the University of British Columbia, Faculty of Medicine, School of Population of Public Health.

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