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Annette M O'Connor a University of
Ottawa School of Nursing and Faculty of Medicine, Loeb Health Research
Institute Clinical Epidemiology Unit, Ottawa Hospital, Civic Campus,
Ottawa, Ontario, Canada K1Y 4E9, b Sisters
of Charity of Ottawa Health Services, Ottawa, Ontario, Canada, c Health Services Research Unit, University of Aberdeen,
Aberdeen, Scotland, d University
of Toronto, Institute for Clinical Evaluative Sciences, North York,
Ontario, Canada, e Department of Medicine, Michigan State University, East
Lansing MI, USA, f General Medicine Unit, Massachusetts General Hospital, Boston,
MA, USA, g Dundas, Ontario, Canada
Correspondence to: A O'Connor
aoconnor{at}LRI.CA
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Abstract |
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Objective:
To conduct a systematic review of
randomised trials of patient decision aids in improving decision making
and outcomes.
Some medical decisions are complex because the evidence on
outcomes is uncertain or the options have different risk-benefit profiles that patients value differently.
1 2
Practice
guidelines for these difficult decisions recommend that patients
understand the probable outcomes of options; consider the personal
value they place on benefits versus risks; and participate with their practitioners in deciding about treatment.3 Decision aids
or shared decision making programmes have been developed as adjuncts to
counselling from practitioners. Their efficacy has been described in
general reports and reviews.4-6 We conducted a systematic overview of the trials of decision aids to determine whether they improved decision making and outcomes for patients facing treatment or
screening decisions.
The search strategy is described in detail
elsewhere.7 We searched the following electronic
databases: Medline (1966-April 98); Embase (1980-November 98); PsycINFO
(1979-March 98); CINAHL (1983-February 98); Aidsline (1980-98);
CancerLit (1983-April 98); and the Cochrane Controlled Trials Register
(1998, Issue 4). Additional studies were searched for in our personal
files and the contents lists of Health Expectations (1998),
Medical Decision Making (January-March 1986-January-March
1998), and Patient Education and Counselling (January
1995-February 1998).
We included randomised controlled trials comparing decision aids to
controls or alternative interventions. Participants were 14 years and
over deciding about screening or treatment options. Decision aids were
defined as interventions designed to help people make specific and
deliberative choices among options (including the status quo) by
providing (at the minimum) information on the options and outcomes
relevant to a patient's health. The aid may also have included
information on the disease or condition; probabilities of outcomes
tailored to personal health risk factors; an explicit exercise to
clarify values; information on others' opinions; and guidance or
coaching in the steps of decision making and communicating with others.
We excluded studies involving hypothetical choices; decisions regarding
lifestyle changes, entry to a clinical trial, or general advance
directives; education programmes not geared to a specific decision; and
interventions designed to promote compliance or to elicit informed
consent for a recommended option.
Evaluation of outcomes depends on the framework used to develop
the decision aids.
5 8-13
To ascertain whether the
decision aids achieved their objectives, we examined a broad range of
positive or negative effects on decision making processes and outcomes of decisions. Although the decision aids focused on diverse clinical decisions, many had similar objectives such as improving knowledge, satisfaction, and participation in decision making and reducing decisional conflict. Other outcomes included the choices patients selected, anxiety, and health related quality of life.
Two reviewers (VF, AR, or JT) screened each study and extracted data
independently using standardised forms. Inconsistencies were resolved
by discussion and consensus. Missing data were obtained from the
authors when possible.
The results of the studies were described individually and pooled when
similar measures were used. We used RevMan V3.114 to
estimate a weighted treatment effect (with 95% confidence intervals). We used weighted mean differences for continuous measures and Mantel-Haenszel methods to calculate pooled relative risks for dichotomous outcomes. Heterogeneity was tested with a We identified 10 387 unique citations from the electronic
databases and nine studies from personal files and contacts. Of these,
500 citations focused on patient decision making and 17 met our
inclusion criteria.15-31
The decision aids focused on 11 screening or treatment decisions (see
BMJ's website for details). All aids included
information on the clinical problem in addition to information on the
options and outcomes. Over half included outcome probabilities,
examples of others, and guidance in the steps of decision making.
A quarter included a values clarification exercise.
Compared with usual care (table 1), decision aids improved
average knowledge scores for the options and outcomes by 13 to 25 points out of 100 (weighted mean difference=19, 95% confidence interval 14 to 25). Compared with simpler interventions, more intensive
decision aids improved average knowledge scores by 0.9 to 6 points
(weighted mean difference 3, 0.7 to 5).
Table 1.
Design:
We included randomised trials of interventions providing structured, detailed, and specific information on treatment or screening options and outcomes to aid decision making. Two reviewers
independently screened and extracted data on several evaluation
criteria. Results were pooled by using weighted mean differences and
relative risks.
Results:
17 studies met the inclusion criteria.
Compared with the controls, decision aids produced higher knowledge
scores (weighted mean difference=19/100, 95% confidence interval 14 to 25); lower decisional conflict scores (weighted mean
difference=
0.3/5,
0.4 to
0.1); more active patient
participation in decision making (relative risk = 2.27, 95% confidence
interval 1.3 to 4); and no differences in anxiety, satisfaction with
decisions (weighted mean difference=0.6/100,
3 to 4), or
satisfaction with the decision making process (2/100,
3 to 7).
Decision aids had a variable effect on decisions. When complex decision
aids were compared with simpler versions, they were better at reducing
decisional conflict, improved knowledge marginally, but did not affect satisfaction.
Conclusions:
Decision aids improve knowledge, reduce
decisional conflict, and stimulate patients to be more active in
decision making without increasing their anxiety. Decision aids have
little effect on satisfaction and a variable effect on decisions. The effects on outcomes of decisions (persistence with choice, quality of
life) remain uncertain.
![]()
Introduction
Top
Abstract
Introduction
Methods
Results
Discussion
References
![]()
Methods
Top
Abstract
Introduction
Methods
Results
Discussion
References
2
test (
=0.10). If clinically and statistically appropriate,
heterogeneous data were analysed with a random effects model.
![]()
Results
Top
Abstract
Introduction
Methods
Results
Discussion
References
Decision aids had a positive impact on decisional conflict in three of four studies (table 2) with reductions ranging from 0.2 to 0.4 out of 5 (weighted mean difference=0.3, 0.1 to 0.4). When the subscales of decisional conflict were examined (data not shown), all studies showed that decision aids were better than usual care or simpler aids in improving patients' perceptions of "feeling informed." 19 25 26 In two of three studies, decisions aids also made patients feel clear about personal values and supported in decision making. 19 26 The uncertainty subscale improved decisional conflict in the short term but not the long term in one study,28 and in another the perceived effective decision subscale improved.19
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Three studies evaluated satisfaction with the decision making process
and satisfaction with the decision using similar interventions, designs, and measures.
15 16 25
One study found that
decision aids improved satisfaction with the decision making
process,15 but the pooled difference was not significant
(weighted mean difference=2,
3 to 7). There were no significant
differences between usual care and decision aids in satisfaction with
the decision in either the individual trials or in the pooled studies
(weighted mean difference=0.6,
3 to 4). Two other studies that used
different measures also found no significant differences in
satisfaction with the decision.
24 28
Fourteen studies assessed the effect of decision aids on the decision made by the participants (table 3). In trials examining decisions about major surgery, decision aids reduced the preference for the more intensive treatment by 21-42% (relative risk=0.74, 95% confidence interval 0.6 to 0.9). In contrast, decision aids did not influence preferences for circumcision of newborn babies (0.96, 0.85 to 1.07).
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Decision aids significantly reduced preferences for prostate specific antigen testing (by 21-48%) in two studies but had no effect in another. There was significant heterogeneity when results were pooled, and the relative risk with a random effects model was not significant (0.83, 0.6 to 1.3). Preferences for screening for breast cancer genes and prenatal testing were not affected by decision aids in individual or pooled studies (1.08, 0.95 to 1.22).
Decision aids increased preferences for hepatitis B vaccine by 76% but did not affect decisions about dental surgery. Decisions regarding hormone therapy were not affected when more intensive methods were compared with simpler methods to aid decisions.
In three studies decision aids showed a consistent trend in increasing the proportion of participants assuming a more active role in decision making compared with usual case controls (pooled relative risk=2.27, 1.3 to 4). 18 19 25
We were unable to combine the results of some studies because of lack
of information on standard deviations. One study found that decision
aids significantly reduced the decline in quality of life after
treatments for benign prostatic hypertrophy,15 but a study
focusing on treatments for ischaemic heart disease showed no
difference.16 Four studies showed that the use of decision
aids did not affect patients'
anxiety.
18 19 24 30
One study found that
patients receiving a decision aid with detailed outcome descriptions
and probabilities had more realistic expectations (accurate perceptions
of the probabilities of outcomes) than those who did not have this
information included.26
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Discussion |
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Despite the variability in decisions, interventions, and measurement, the trials were consistent in showing that decision aids do a better job than usual care in improving patients' knowledge about options, reducing their decisional conflict, and stimulating patients to take a more active role in decision making without increasing their anxiety. Decision aids had a variable effect on decisions and virtually no effect on satisfaction. The effects on the outcomes of decisions (such as quality of life) are still uncertain. When compared with simpler versions, more intensive decision aids reduced decisional conflict, improved knowledge marginally, and had no different effect on satisfaction.
Knowledge, comfort, and empowerment
The largest and most consistent benefit of decision aids over
usual care is better knowledge of options and outcomes. The 19%
improvement in scores is clinically important because the scores of
people in the usual care group were inadequate for informed decision
making and they often made different decisions. These results suggest
that doctors' usual methods may not be good enough for informing
patients about these complex, value laden decisions. Patients need to
comprehend the options and outcomes in order to consider and
communicate the personal value they place on the benefits versus the harms.
Altering choices
The variable effect of decision aids on patients' decisions may
be due to several reasons. Firstly, most studies were underpowered to
detect important differences. Secondly, some of the 11 options may have
been underused at baseline and others overused. This would influence
the direction of effect once patients become informed and involved in
decision making. Thirdly, patients may react differently to the
outcomes being considered in the different decisions. Some decisions
may be driven predominantly by the probabilities of outcomes and others
by the values for outcomes. For example, the aids seem to have a small
effect on decisions about major surgical procedures. This may be
because patients have inflated perceptions of the probability of
benefit and do not understand the probabilities of risks and
uncertainties in evidence of effectiveness. When given better knowledge
of the outcomes and their associated probabilities, fewer patients may decide that the benefits outweigh the risks. In contrast, decision aids
had little effect on circumcisions. This decision may be driven more by
values and norms than by perceived probabilities of medical outcomes,
as is suggested by the high rates of use in both arms of the trials.
Satisfaction
The studies showed no effect on satisfaction with decision making.
This may because it is difficult to show improvements in satisfaction
when control ratings are already quite high and when choices are
inherently difficult because of competing benefits and risks.
Furthermore, once the decision is made, people may find it more
psychologically comforting to say that they are satisfied with it than
to entertain doubts about what they chose.32
Further research
The small differences between simpler and more complex versions of
decision aids indicate a need to establish the essential ingredients in
decision aids and to identify the patients who are most likely to
benefit from more complex versions.
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What is already known on this topic Patient decision aids or shared decision making programmes aim to help patients come to informed decisions Studies of their effectiveness have often been small and have focused on a wide range of medical conditions What this study adds Decision aids are better than usual care in improving patients' knowledge, comfort, and participation in decision making without increasing anxiety They have little effect on satisfaction and variable effect on patients' decisions Compared with simpler versions, more detailed aids improve patients' comfort with decision making and marginally improve knowledge |
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Acknowledgments |
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Contributors: All authors contributed to the design of the protocol, the interpretation of results, and the revision and final approval of the final paper. AO'C led the team and JT coordinated the project. AO'C, MH-R, AR, VF, and JT pilot tested the data extraction forms. AR, VF, and JT screened studies and extracted data. AR, JT, and AO'C analysed the results. The Cochrane Consumers and Communication Review Group (editor Alex Jadad) provided peer review and advice regarding the research protocol. Maire O'Donnell from the University of Aberdeen Health Services Research Unit assisted with literature searching. AO'C is the study guarantor.
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Footnotes |
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Funding: The overview was supported by a group grant from the Medical Research Council of Canada. At the time of the study AO'C was funded by the Ontario Ministry of Health, VE held a special research fellowship from the Leverhulme Trust, and HL-T was a national health scholar funded by Health Canada's National Health Research Development Program.
Competing interests: None declared.
website extra: A table giving details of the studies included in the review is available on the BMJ's website www.bmj.com
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(Accepted 19 August 1999)