Decision Aids for Patients
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Background: Patients want to be more involved in medical decision-making. To this end, some decision aids are now available.
Methods: We present an overview of this subject, in which we explain the terms “shared decision-making”, “decision aid”, and “evidence-based patient information” and survey information on the available decision aids in German and other languages on the basis of a literature search in MEDLINE, EMBASE and PsycInfo and a current Cochrane Review. We also searched the Internet for providers of decision aids in Germany.
Results: Decision aids exist in the form of brochures, decision tables, videos, and computer programs; they address various topics in the prevention, diagnosis, and treatment of disease. They typically contain information on the advantages and disadvantages of the available options, as well as guidance for personal decision-making. They can be used alone or as a part of structured counseling or patient education. Minimal quality standards include an adequate evidence base, completeness, absence of bias, and intelligibility. Our search revealed 12 randomized controlled trials (RCTs) of decision aids in German and 106 RCTs of decision aids in other languages. These trials studied the outcome of the use of decision aids not just with respect to clinical developments, but also with respect to patient knowledge, adherence to treatment regimens, satisfaction, involvement in decision-making, autonomy preference, and decisional conflicts.
Conclusion: Only a small fraction of the available decision aids were systematically developed and have been subjected to systematic evaluation. Patients are still not receiving the help in decision-making to which medical ethics entitles them. Structures need to be put in place for the sustainable development, evaluation and implementation of high-quality decision aids.
People have a right and an ethics-based entitlement to self-determination. They want to be involved in health- and disease-related decisions (1). This is especially relevant for measures that are aimed at healthy people (for example, screening tests for early detection of cancer), for measures with a dubious balance of benefit-to-harm, and for chronic diseases with an uncertain course, such as cancer or multiple sclerosis (MS).
Decisions that are made jointly by patients and physician are referred to as shared decision making (SDM) (2). Support for weighing the options in an individualized manner is given by decision aids (3) and evidence-based patient information (EBPI) (4).
This study aims to provide a descriptive overview of international and German decision aids as well as providers of decision aids in Germany. The concept of decision aid is discussed in the context of EBPI and SDM. Key aspects of the development, evaluation, and implementation are presented and exemplified using decision aid tools for MS.
An eAppendix with further information about quality criteria and decision aids (in German) is available on our homepage: www.chemie.uni-hamburg.de/igtw/Gesundheit/publikationen/pub_lenz.html
Shared decision making
There is no uniform definition of SDM (5). SDM represents a certain style of communication between patients and health professionals and takes place when the people involved in making the decision exchange relevant information in order to jointly make and implement a decision (6). According to the basic idea of evidence-based medicine (7), SDM should be based on reliable EBPI and take into consideration the participant’s individual attitude.
Decision aids address preventive, diagnostic, and therapeutic measures and should help to balance individual options (3, 8). Their purpose is not to advise for specific measures or to increase treatment adherence. Decision aids are available as brochures, videos, web programs, or decision tables, and they incorporate various goals and teaching strategies (9). For example, supplying relevant information should motivate patients to reflect on their own attitudes and, consequently, to participate in decision-making. Conversely, motivating patients to think about their own values can represent an entry point into an information process that encourages patients to participate in SDM.
Decision aid development is complex and usually includes a variety of theoretical and empirical groundwork (10). Since the use of decision aids can impact patient care (3), a thorough evaluation of their effectiveness through randomized controlled trials (RCTs) is required prior to their implementation.
Various tools are available to evaluate the quality of decision aids (8), including the International Patient Decision Aid Standards (IPDAS) Collaboration assessment checklist IPDASi (IPDAS instrument) (14), the instrument Matrix to evaluate the development and evaluation processes of decision aids (9), and the instrument EQIP (Ensuring Quality Information for Patients) to evaluate information quality (15).
Evidence-based patient information
EBPI is a key component of decision aids, and internationally defined quality criteria are available (4, 11, 12). Ethical guidelines (13) clarify what content and meta-information for patients is relevant, and include
- information about the natural course of the disease (e.g., symptoms and prognosis of the disease without intervention);
- a comprehensive list of all options, which includes the possibility of (initially) refraining from intervention;
- the probability of success of, failure of, and harm from the upcoming medical interventions;
- patient-relevant outcomes;
- lack of evidence;
- data about possible false-positive and false-negative results for diagnostic measures.
EBPI should be easily understandable for the general public and presented in an unbiased manner. For some of the presented criteria, good evidence with respect to cognitive endpoints is lacking (Box 1). Developing health information requires that target group representatives are involved in the development process (4).
Developing EBPI is time-consuming and complex. Ensuring quality information requires, among other things, systematic searches for medical and scientific literature (for example, searching for the clinical picture of a disease, available options and their effectiveness) and a critical appraisal of these. Updating EBPI content is important, especially considering the current short half-life of scientific information.
To identify non-German decision aids, database searches of the current Cochrane reviews (3) were supplemented with searches of MEDLINE (Ovid), EMBASE (Ovid) and PsycInfo (Ovid) up to August 2011 (eAppendix; available on our homepage [in German]). Decision aids were included if they met the Cochrane criteria and had been tested for effectiveness in RCTs.
To identify German decision aids, the term “patient information” was added to the search strategy and the language was limited to German (eAppendix). Known publications and reference lists of identified studies were searched for additional publications. Only those German decision aids were included in the study that met the Cochrane criteria and had been evaluated in RCTs.
A systematic database search was considered to be not appropriate for determining which providers are usually identified by lay people on the internet; instead, a Google search was done for the German terms “Entscheidungshilfe” (decision support) AND “Patient” (patient), and “evidenzbasiert” (evidence-based) AND “Patienteninformation” (patient information). The first 100 hits were screened for providers. Moreover, websites of known providers were screened for decision aids or EBPI as well as for links to other providers. Identified providers were assigned to one of three categories (Table 1).
International decision aids tested for efficacy
From the recent Cochrane review (3), 82 RCTs for non-German decision aids were initially extracted. From our own database research over the period January 2009 to August 2011, we identified and assessed 3693 titles and 54 publications (with full texts). Of these, we included 24 publications that covered 20 decision aids, and excluded 30 that did not contain a RCT or that evaluated a decision aid that did not meet the Cochrane criteria. In addition to the RCTs included in the current Cochrane review, we identified 106 RCTs for non-German decision aids (additional figures and tables are available [in German] on our homepage).
Decision aids address a variety of preventive, diagnostic and therapeutic options (3) and are to be used individually or as components of SDM programs. Additionally, consultations with physicians and health care professionals often take place. The main evaluation parameters considered knowledge, attitude, decisions taken, informed choice, decision confidence, patient satisfaction with respect to the decision, and patient preferences.
German decision aids tested for effectiveness
Of the 391 titles identified, we tested 339 and evaluated 19 based on their full texts. A total of 12 RCTs of 10 German decision aids were included (Table 2); seven of the full-text publications were excluded because they did not contain RCTs or did not evaluate a decision aid. Four of the 12 RCTs that we included are also in the current Cochrane review.
In addition to indication-specific clinical endpoints, we also evaluated knowledge, treatment adherence, patient satisfaction, patient participation in decision-making, autonomy preferences, and decision conflict as parameters for results. RCT validity was not assessed here (additional figures and tables are available [in German] on our homepage).
Providers of decision aids in German
We identified several German providers of decision aids (Table 1), as well as providers of patient guidelines or patient information, who based their content on guidelines from scientific medical societies (for example, the German Society of General Practice and Family Medicine [Deutsche Gesellschaft für Allgemeinmedizin und Familienmedizin). We even identified internet sites which did not directly provide information but rather gave links to providers, decision aids, and EBPI (for example, the German Network for Evidence-Based Medicine [Deutsches Netzwerk evidenzbasierte Medizin] and the German Cochrane Centre [Deutsches Cochrrance Zentrum]). However, it was not possible for most providers to determine to which extent information is actually evidence-based.
Development, evaluation, and implementation, as exemplified for multiple sclerosis
Funded by the German Federal Ministry of Health (2001–2004), the Unit of Health Sciences and Education at the University of Hamburg, in collaboration with the University Medical Center Hamburg-Eppendorf (UKE), developed and evaluated two decision aids for people with multiple sclerosis (MS) (Box 2). The decision aid on immunotherapy is composed of a detailed information brochure and a decision worksheet. In addition to the detailed information brochure (e1), a second decision aid for MS relapse management is provided through a four hour group training, discussion and reflection for patients with MS and their relatives (16). Relapse management faces several uncertainties and is prototypical for the use of decision aids, since relapses can differ greatly and have unclear prognostic significance (e2). Guidelines recommend a short-term, high-dose intravenous therapy with glucocorticoids (e3), yet this is based on weak evidence: Only short-term effects have been demonstrated (with no apparent long-term benefit of administering oral glucocorticoids over placebos), and adverse effects are common and can be severe (e2).
Since no evidence-based decision aids were available (17), decision aids were developed based on several preliminary studies. The decision aids should help people with MS to recognize that, in the event of a relapse, they have several possible choices, including the option of waiting. People with MS were involved in all stages of development. Two people conducted the training: a nurse and one person with MS.
RCTs revealed that fewer relapses occurred following intervention with intravenous therapy (22% rate of relapses in the intervention group) as compared to the control group (44%, p<0.0001), and that patients receiving the intervention had increased knowledge of risk and were more autonomous in their decision-making (16).
In the subsequent implementation study (e4), 31 participants were trained in a train-the-trainer program to provide the decision aids at various centers across Germany. The results of 261 participants with MS demonstrated that the program could be put into practice, but with different implementation barriers.
At present, the program is solidly implemented at two rehabilitation centers for people with MS, the UKE outpatient clinic and a self-help organization. The program was transferred to a Canadian center at the end of 2011 (additional figures and tables are available [in German] on our homepage.)
The authors identified several internet sites that offer a variety of information which is labeled as evidence-based patient information or decision aid. However, whether the content is indeed evidence-based is often difficult to determine.
Patients who search the internet for decision aids are likely to use terms for their individual indications, such as “diabetes” or “heart attack.” Although this review does not address indication-specific searching, the lack of clarity in our obtained search results is likely to be similar to that of indication-specific searches.
The copious amount and variety of available information contrasts starkly with the absence of high-quality decision aids. A yet unresolved problem is the non-transparency of information quality. Even when patient information and decision aids are labeled as “evidence-based, ” the content and presentation of information is often not evidence-based (18). Different quality seals, such as “Health on the Net” (HON) (e5) or DISCERN (e6), should demonstrate that the information is reliable. In Germany, for example, the HON seal is used on patient information sites from the Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen, IQWiG), the German Medical Association (Bundesärztekammer, BÄK), and the National Association of Statutory Health Insurance Physicians (Kassenärztliche Bundesvereinigung, KBV) (Table 1). However, central EBPI quality aspects such as scientific accuracy, completeness, and content presentation are not taken sufficiently into consideration by the quality seal (19). Users currently have little opportunity to assess the reliability of the information available.
Much of what is labeled as decision aid is freely available through the internet. However, our database searches revealed that relatively few decision aids have been evaluated for benefit and harm in RCTs. On the other hand, there are good examples of German-language decision aids that have been systematically developed and have been proven to be effective (Table 2).
It is difficult to draw a clear conceptual distinction between EBPI and decision aids. If an EBPI is designed to be used for decision-making, it basicaly satisfies the IPDAS-criteria (8). Additionally, EBPI can function alone, as exemplified by the “drug facts box” (e7), in which the benefits and adverse effects of a drug are directly compared using absolute risks. In fact, a RCT demonstrated that a drug facts box, as compared to standard information, improved knowledge about benefits and adverse effects of a drug and may help to correct unrealistic expectations about their effectiveness (e7).
Prior to implementing a decision aid, its effectiveness should be tested in a RCT. To evaluate how a decision aid works under certain conditions, it is usually necessary to conduct additional theoretical work and empirical preliminary studies. Systematical retrieval of all available trial publications is a methodological problem (20). One proposal for overcoming this is to develop specifically structured literature databases that allow complete identification, which would facilitate quality assessment (21, 22). An additional problem is obtaining a critical appraisal of identified literature. On the one hand, the published works are methodologically heterogeneous, which requires that the assessor has a broad methodological knowledge. On the other hand, the conditions (contextual factors) under which the decision aids were developed and/or evaluated are not always transparent. In these cases, whether a decision aid will be successful or counterproductive for users under the user’s terms and conditions remains an open question.
Whether using a decision aid is helpful for a patient to reach a decision can depend on several factors. A basic requirement is that patients understand the contents, and this must be verified. In this context, health care professionals such as breast-care nurses or diabetes educators could play stronger roles (1). Additionally, successful implementation appears to require that doctors and medical staff are trained in evidence-based medicine and SDM, among other things (23, e6).
The work presented here is not a systematic review but rather an inventory of compiled literature, which was not systematically analyzed. A systematic review was published by the Cochrane Collaboration (3). It was updated in October 2011 but only contains research until December 2009. In contrast to the Cochrane review, the present work reflects various aspects of the development, evaluation and implementation of decision aids, foremost in Germany.
People want to have access to complete, unbiased and comprehensive evidence-based information, and indeed they have a right and an ethics-based entitlement to this; however, this need is currently inadequately met. Structures have to be developed that allow high-quality decision aids and evidence-based patient information to be sustainably developed, evaluated and implemented. This is especially urgent for cancer and other chronic diseases.
Quality criteria for decision aids should be developed, catalogued, and validated. These criteria should go beyond IPDAS criteria and take into consideration whether contents are evidence-based as well as the transparency of the development, implementation and evaluation of the contents. Currently, guidelines are being developed for health information providers, which should improve the quality of information in the long term (24).
To make German indication-specific decision aids available, it will be necessary to create an independent and publically-available database where authors could provide current decision aids and meta-information. In addition to available evidence about development and evaluation, this database should include quality information about whether the contents are evident-based and about the implementation conditions.
We would like to thank Martina Bunge, Anja Gerlach, Sascha Köpke, and Anke Steckelberg for their highly constructive contribution to this work.
Conflict of interest statement
The authors declare that no conflict of interest exists.
Manuscript submitted on 24 October 2011, revised version accepted on 16 January 2012.
Translated from the original German by Veronica A. Raker, PhD.
Dr. Matthias Lenz
Fakultät für Mathematik, Informatik und Naturwissenschaften
20146 Hamburg, Germany
@For eReferences please refer to:
University Medical Center Hamburg-Eppendorf, Department of Primary Medical Care: Dr. phil. Kasper
|1.||Mühlhauser I, Meyer G, Steckelberg A: Patienten wollen mitentscheiden, doch Informationsbasis und Strukturen fehlen. ZFA 2010; 86: 412–7.|
|2.||Edwards A, Elwyn G: Shared decision making in health care: achieving evidence based patient choice, 2 e. Oxford: Oxford University Press 2009.|
|3.||Stacey D, Bennett CL, Barry MJ, et al.: Decision aids for people facing health treatment or screening decisions. Cochrane Database of Systematic Reviews 2011; CD001431. MEDLINE|
|4.||Bunge M, Mühlhauser I, Steckelberg A: What constitutes evidence-based patient information? Overview of discussed criteria. Patient Educ Couns 2010; 78: 316–28. CrossRef MEDLINE|
|5.||Charles C, Gafni A, Freeman E: Implementing shared decision making and treatment decision aids: A cautionary tale. Psicooncologia 2010; 7: 243–55.|
|6.||Charles C, Gafni A, Whelan T: Shared decision-making in the medical encounter: what does it mean? (Or it takes at least two to tango). SocSciMed 1997; 44: 681–92. CrossRef|
|7.||Strauss S, Glaziou P, Richardson WS, Haynes RB: Evidence-based medicine: how to practice and teach it. 4th edition. Edinburgh: Churchill Livingstone 2010.|
|8.||International Patient Decision Aid Standards (IPDAS)Collaboration: International Patient Decision Aid Standards. http://ipdas.ohri.ca/.|
|9.||Lenz M, Kasper J: MATRIX – development and feasibility of a guide for quality assessment of patient decision aids. GMS Psychosoc Med 2007; 4: Doc10. MEDLINE PubMed Central|
|10.||Craig P, Dieppe P, Macintyre S, Michie S, Nazareth I, Petticrew M: Developing and evaluating complex interventions: new guidance. UK Medical Research Council 2008. www.mrc.ac.uk/complexinterventionsguidance|
|11.||Steckelberg A, Berger B, Köpke S, Heesen C, Mühlhauser I: Kriterien für evidenzbasierte Patienteninformationen. Z Arztl Fortbild Qualitatssich 2005; 99: 343–51. MEDLINE|
|12.||Trevena LJ, Davey HM, Barratt A, Butow P, Caldwell P: A systematic review on communicating with patients about evidence. Journal of Evaluation in Clinical Practice 2006; 12: 13–23. CrossRef MEDLINE|
|13.||General Medical Council: Consent: patient and doctors making decisions together. www.gmc-uk.org/guidance/ethical_guidance/consent_guidance/Consent_guidance.pdf.|
|14.||Elwyn G, O’Connor AM, Bennett C, et al.: Assessing the quality of decision support technologies using the International Patient Decision Aid Standards instrument (IPDASi). PLoS ONE 2009; 4: e4705. CrossRef MEDLINE PubMed Central|
|15.||Charvet-Berard AI, Chopard P, Perneger TV: Measuring quality of patient information documents with an expanded EQIP scale. Patient Education & Counseling 2008; 70: 407–11. CrossRef MEDLINE|
|16.||Köpke S, Kasper J, Mühlhauser I, Nübling M, Heesen C: Patient education program to enhance decision autonomy in multiple sclerosis relapse management: A randomized-controlled trial. Multiple Sclerosis 2009; 15: 96–104. CrossRef MEDLINE|
|17.||Köpke M, Mühlhauser I: Decision aids in multiple sclerosis. In: Edwards A, Elwyn G, (eds): Shared decision making in health care: achieving evidence based patient choice, 2e. Oxford: Oxford University Press; 2009: 257–61.|
|18.||Feldman-Stewart D, Brennenstuhl S, McIssac K, et al.: A systematic review of information in decision aids. Health Expect 2007; 10: 46–61. CrossRef MEDLINE|
|19.||Köpke S, Berger B, Steckelberg A, Meyer G: In Deutschland gebräuchliche Bewertungsinstrumente für Patienteninformationen – eine kritische Analyse. Z Arztl Fortbild Qualitatssich 2005; 99: 353–7. MEDLINE|
|20.||Lenz M, Kasper J, Mühlhauser I: Searching for diabetes decision aids and related background information. DiabetMed 2006; 23: 912–6. CrossRef MEDLINE|
|21.||Lenz M, Steckelberg A, Richter B, Mühlhauser I: Meta-analysis does not allow appraisal of complex interventions in diabetes and hypertension self-management: a methodological review. Diabetologia 2007; 50: 1375–83. CrossRef MEDLINE|
|22.||Warsi A, Wang PS, LaValley MP, Avorn J, Solomon DH: Self-management education programs in chronic disease: a systematic review and methodological critique of the literature. ArchInternMed 2004; 164: 1641–9. CrossRef MEDLINE|
|23.||Loh A, Simon D, Wills CE, Kriston L, Niebling W, Harter M: The effects of a shared decision-making intervention in primary care of depression: A cluster-randomized controlled trial. Patient Education and Counseling 2007; 67 (3 SPEC. ISS.): 324–32.|
|24.||Steckelberg A: Projekt: Entwicklung und Pilotierung einer Leitlinie zur Erstellung und Präsentation von evidenzbasierter Patienteninformation (EBPI). www.chemie.uni-hamburg.de/igtw/Gesundheit/projekte/patientenleitlinie.html|
|25.||Steckelberg A, Hülfenhaus C, Haastert B, Mühlhauser I: Effect of evidence based risk information on „informed choice“ in colorectal cancer screening: Randomised controlled trial. BMJ 2011; 342: d3193; doi:10.1136/bmj.d3193. CrossRef MEDLINE PubMed Central|
|e1.||Kasper J, Köpke S, Mühlhauser I, Heesen C: Evidence-based patient information about treatment of multiple sclerosis – a phase one study on comprehension and emotional responses. Patient Education & Counseling 2006; 62: 56–63. CrossRef MEDLINE|
|e2.||Köpke S, Heesen C, Kasper J, Mühlhauser I: Steroid treatment for relapses in multiple sclerosis – the evidence urges shared decision-making. Acta Neurologica Scandinavica 2004; 110: 1–5. CrossRef MEDLINE|
|e3.||Deutsche Gesellschaft für Neurologie: Diagnostik und Therapie der Multiplen Sklerose. Leitlinien für Diagnostik und Therapie in der Neurologie; 4th revised edition 2008. http://www.awmf.org/uploads/tx_szleitlinien/030-050_S1_Multiple_Sklerose__Diagnostik_und_Therapie_10-2008_10-2013.pdf.|
|e4.||Köpke S, Richter T, Kasper J, Mühlhauser I, Flachenecker P, Heesen C: Implementation of a patient education program on multiple sclerosis relapse management. Patient Education & Counseling 2012; 86: 91–7. CrossRef MEDLINE|
|e5.||Health On the Net Foundation (HON): www.hon.ch|
|e7.||Schwartz LM, Woloshin S, Welch HG: Using a drug facts box to communicate drug benefits and harms: two randomized trials. Annals of Internal Medicine 2009; 150: 516–27.|
|e8.||Köpke S: Evidenz-basierte Patienteninformation und partizipative Entscheidungsfindung bei Multipler Sklerose. Dissertation, Universität Hamburg. http://ediss.sub.uni-hamburg.de/frontdoor.php? source_opus=3352.|
|e9.||Vodermaier A, Caspari C, Koehm J, Kahlert S, Ditsch N, Untch M: Contextual factors in shared decision making: A randomised controlled trial in women with a strong suspicion of breast cancer. British Journal of Cancer 2009; 100: 590–7. CrossRef MEDLINE PubMed Central|
|e10.||Vodermaier A, Caspari C, Wang L, Koehm J, Ditsch N, Untch M: How and for whom are decision aids effective? Long-term psychological outcome of a randomized controlled trial in women with newly diagnosed breast cancer. Health Psychology 2011; 30: 12–9. CrossRef MEDLINE|
|e11.||Wilhelm D, Gillen S, Wirnhier H, Kranzfelder M, Schneider A, Schmidt A, et al.: Extended preoperative patient education using a multimedia DVD-impact on patients receiving a laparoscopic cholecystectomy: a randomised controlled trial. Langenbecks Archives of Surgery 2009; 394: 227–33. MEDLINE|
|e12.||Genz J, Haastert B, Meyer G, Steckelberg A, Müller H, Verheyen F, et al.: Blood glucose testing and primary prevention of diabetes mellitus type 2 – evaluation of the effect of evidence based patient information. BMC Public Health 2010; 10: 15. MEDLINE|
|e13.||Krones T, Keller H, Sönnichsen A, Sadowski EM, Baum E, Wegscheider K, et al.: Absolute cardiovascular disease risk and shared decision making in primary care: a randomized controlled trial. Annals of Family Medicine 2008; 6: 218–27. MEDLINE|
|e14.||Krones T, Keller H, Becker A, Sönnichsen A, Baum E, Donner-Banzhoff N: The theory of planned behaviour in a randomized trial of a decision aid on cardiovascular risk prevention. Patient Education and Counseling 2009; 78: 169–76. MEDLINE|
|e15.||Kasper J, Köpke S, Mühlhauser I, Nübling M, Heesen C: Informed shared decision making about immunotherapy for patients with multiple sclerosis (ISDIMS): A randomized controlled trial. European Journal of Neurology 2008; 15: 1345–52. CrossRef MEDLINE|
|e16.||Bücker B, Butzlaff M, Isfort J, Koneczny N, Vollmar HC, Lange S, et al.: Effect of written patient information on knowledge and function of patients with acute uncomplicated back pain (PIK Study). Gesundheitswesen 2010; 72: e78–88. MEDLINE|
|e17.||Hamann J, Langer B, Winkler V, Busch R, Cohen R, Leucht S, et al.: Shared decision making for in-patients with schizophrenia. Acta Psychiatr Scand 2006; 114: 265–73. MEDLINE|
|e18.||Heesen C, Kasper J, Segal J, Köpke S, Mühlhauser I: Decisional role preferences, risk knowledge and information interests in patients with multiple sclerosis. Multiple Sclerosis 2004; 10: 643–50. CrossRef MEDLINE|
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