ORIGINAL ARTICLE

Decision Aid Influences on Factors Associated with Patient Empowerment prior to Cancer Treatment Decision Making Dana L. Alden, PhD

Background. Despite progress, models that incorporate antecedent and mediating factors associated with shared decision making (SDM)–related outcomes remain limited. An experimental study tests patient decision aid (DA) effects on a network of antecedents and mediators associated with patient empowerment prior to a medical decision-making consultation regarding cancer treatment. Methods. A pilot study initially evaluated measurement scales, model fit, and the overall effect of the DA experience. The pilot compared matched treatment and control group samples of US adult online panel members exposed to a vignette about meeting their dermatologist to decide on skin cancer treatment. The treatment group also experienced a skin cancer DA with treatment options and value clarification activity, while the control group did not. The main study employed a randomized experimental design to formally test hypothesized path coefficients across the groups. Results. The pilot study suggested an overall enhanced DA effect on self-empowerment. In the experimental study,

the DA experience strengthened the direct path from desire for medical information to self-empowerment and the indirect path from comprehension/participation confidence to self-empowerment through cancer attitude. The DA had no strengthening effect on the direct path from life satisfaction to self-empowerment, but in the DA condition, the factor appeared to play a role by contributing to the enhanced association between confidence and cancer attitude. Conclusion. Evidence from this research indicates that experiencing a DA prior to treatment decision making affects patient empowerment through a network that includes desire for information, life satisfaction, and multiple mediators. The studies also demonstrate the role that theorybased, multigroup structural equation modeling (SEM) can play in increasing understanding of DA effects. Such understanding is critical to improving SDM between patients and their physicians. Key words: decision aids; patient empowerment; cancer; shared decision making. (Med Decis Making 2014;34:884–898)

INTRODUCTION

empowerment, such as decision preparedness and actual participation in decision making.4 While positive DA main effects related to patient empowerment are well established, empirically validated models of antecedents, mediators, and outcomes that illuminate aspects of the DA experience leading to this desirable outcome remain scarce. Seeking to initiate research that addresses this gap, a cross-sectional pilot study and a subsequent experimental study provide initial evidence on behalf of a model with multiple predictors and processes that are associated with enhanced patient empowerment following the DA experience. Such models should prove helpful in developing more effective empowerment interventions involving DAs and other forms of health education designed to improve SDM between patients and their physicians. The context for both studies involves experiencing a DA versus not experiencing a DA prior to meeting with a dermatologist to discuss treatment options

Patient empowerment is known to play an important role in facilitating the 2-way communication that is central to shared decision making (SDM).1–3 Patient decision aids (DAs) have been shown to enhance outcomes associated with patient

Received 5 March 2013 from the University of Hawai’i at Manoa, Honolulu, HI, USA (DLA). This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Revision accepted for publication 18 April 2014. Address correspondence to Dana L. Alden, University of Hawai’i at Manoa, 2404 Maile Way, Honolulu, HI 96822, USA; e-mail: [email protected]. Ó The Author(s) 2014 Reprints and permission: http://www.sagepub.com/journalsPermissions.nav DOI: 10.1177/0272989X14536780

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Figure 1 Conceptual model.

for basal cell carcinoma. Although definitions and uses of the term patient empowerment vary in the health care literature, the construct is typically referred to as multidimensional,5,6 with one of the dimensions involving an overall sense of personal power and agency relative to the medical situation, in this case, a cancer diagnosis prior to treatment decision making. This view of empowerment is consistent with other frequently cited definitions that focus on the absence or decrease of powerlessness, helplessness, loss of control over one’s life and other related constructs.7,8 Identifying antecedents that are associated with enhanced empowerment over a positive cancer diagnosis prior to a medical consultation and that are strengthened by the DA experience is important as feelings of powerlessness and helplessness during the consultation may lower motivation to comply with treatment thereafter.9 Such results are contrary to the fundamental goals of SDM, which strives to empower patients as active participants in decision making and treatment at the levels they desire. Deeper understanding of possible moderating effects of the DA experience on relevant antecedents and mediators is vital to developing health communication strategies that enhance feelings of empowerment vis-a`-vis a cancer diagnosis. Previous SDM research and the broader psychology literature suggest that several antecedents and mediators are likely to be both positively associated with patient empowerment and positively strengthened by a DA experience. As such, the proposed model focuses on 2 exogenous antecedents and 2

endogenous mediators that may play important roles in better understanding the processes through which the DA experience affects empowerment. Although grounded in theory, the model is not meant to capture all of the factors related to patient empowerment that are also moderated by a DA experience. Rather, the model reflects an initial effort to identify individual difference predictors from the SDM literature and the broader psychology literature that past research suggests are positively associated with empowerment and can therefore serve as building blocks for subsequent research. In this spirit, the proposed exogenous antecedents are the patient’s 1) desire for medical information, a construct from the SDM literature,10 and 2) overall satisfaction with life, a construct from the broader psychology literature.11 The 2 endogenous mediators are from the SDM literature. They are 1) patient’s confidence regarding cancerrelated comprehension and decision making participation12 and 2) patient’s attitude toward the cancer12 (see Figure 1). The 2 exogenous variables are hypothesized to play more important roles in predicting empowerment when the patient experiences a DA (versus the No DA experience) prior to a skin cancer treatment consultation. Desire for medical information has been used in numerous studies, most often as a predictor in models that do not involve simultaneous moderators and mediators (e.g., regression).13 The construct varies from low to high, reflecting a chronic orientation toward the perceived value of obtaining information as part of the consultation process. Past

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research has identified significant variation in patients’ desire for medical information.14–16 Given the importance and value of information to feelings of power and the absence or reduction of helplessness, this antecedent is likely to positively predict patient empowerment. Furthermore, patients who desire medical information should feel higher levels of empowerment following their DA experience (the DA group) relative to those who also desire information but do not experience the DA (the No DA group). As a result, the direct positive relationship between this exogenous predictor and empowerment should be significantly stronger for the DA versus the No DA group (path 1). However, stages-of-change models17 and hierarchyof-effects18 models suggest that the impact of desire for medical information on empowerment is likely to be mediated by at least 2 other endogenous constructs: 1) higher confidence regarding cancer decisionmaking information and participation with their physician and 2) more positive attitudes toward having cancer. The rationale for mediation effects follows. First, individuals with a high desire for medical information are likely to have engaged in information-seeking behaviors in the past that increased feelings of personal agency and were reinforced over time by real and self-perceived rewards such as enhanced confidence. On average, patients with higher desire for medical information should tend to have higher confidence in their cancerrelated participation and decision-making abilities. As a result, the association between desire for medical information and confidence should be positive in both the DA and No DA groups. However, those who desire medical information and are provided with an information-rich DA experience (information-poor No DA experience) should feel more (less) confident regarding their ability to comprehend and participate in a subsequent decision-making medical consultation. This suggests that the DA experience will positively strengthen the association (path 2) between desire for medical information and patient confidence. Second, higher levels of medical decision-making participation/comprehension confidence should underlie or serve as a basis for stronger attitudes toward cancer based on basic attitude theory.19,20 As a result, comprehension/participation confidence should be positively associated with the second endogenous mediator, cancer attitude (path 3). More positive attitudes toward having cancer should, in turn, predict stronger patient feelings of empowerment over the cancer diagnosis (path 4). In addition,

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given prior research on DA main effects,21 the preconsultation DA experience should strengthen associations between patient participation/decision-making confidence and cancer attitude (path 3) as well as between cancer attitude and patient empowerment (path 4). Several potential antecedents to patient empowerment over a cancer diagnosis can also be identified in the broader psychology literature, for example, values such as self-direction22 and personality traits such as conscientiousness.23 In addition, some of these antecedents are likely to be differentially sensitive to the context of the DA versus No DA experience. One individual difference construct that appears to be particularly important in both regards is life satisfaction.24 This construct is directly related to maintaining positive emotional states25 as well as using positive adjustment strategies.26 In addition, it is negatively related to emotional distress.27 Past research has emphasized life satisfaction as an outcome. However, interest in its role as an antecedent is increasing.28 Even so, research establishing a positive association between this important individual difference construct and patient empowerment is lacking. Given life satisfaction’s positive relationship to maintaining overall confidence, positive attitudes, and higher empowerment, the construct is likely to have both direct and indirect effects on patient empowerment. While life satisfaction is expected to positively predict empowerment (path 7), it is also expected to be associated with the construct indirectly through its positive relationship with patient comprehension/participation confidence (path 5) and cancer attitude (path 6). Furthermore, the DA experience is hypothesized to significantly strengthen the direct (path 7) and indirect pathways (paths 5 and 6) for the following reasons. First, patients who are more satisfied with life should generally feel more empowered regardless of whether they are in the DA or No DA group.29 However, if the DA experience heightens access to direct relationships between life satisfaction and personal agency (path 7), this positive relationship should be even stronger for those with higher life satisfaction in the DA group. Second, experiencing the DA should increase patients’ active consideration of valuerelated issues and, hence, increase accessibility to thoughts about life satisfaction.30 As a result, life satisfaction for the DA group should more strongly relate to downstream constructs that are complementary such as feeling confident about comprehending/participating in decision-making conversations with one’s physician and having a positive attitude toward

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managing cancer’s effects on well-being. For these reasons, the positive main effect paths between life satisfaction and confidence (path 5) and life satisfaction and cancer attitude (path 6) are expected to be significantly enhanced by the experience of a DA. Formal tests of these hypothesized relationships will be undertaken in the main experimental study that follows the pilot study, described in the next section.

PILOT STUDY: METHODS Pilot Study: Design and Procedures A cross-sectional pilot study was undertaken with 2 objectives in mind: 1) to pretest the measurement model prior to use in the randomized experiment and 2) to explore the overall impact on patient empowerment of the hypothesized antecedents in the structural model. In the pilot study, 2 matched US online samples, recruited within 6 mo of each other by panel management firms that contract with Qualtrics, an established online survey company, were exposed to a vignette in which they were recently diagnosed with skin cancer. No individuallevel information was obtained, and data were stored on password-protected servers. Although the study used a convenience sample that receives incentives for panel participation and voluntarily joins studies in response to e-mail invitations from the online survey company, respondents were screened on demographic criteria to adhere to preset quotas. In addition, respondents who failed an attention test and/or took less than 5 min to complete the survey were deleted from the sample. Additional steps following the checklist for Internet surveys31 were taken to ensure the integrity of the data collection process. A full description is available from the author. Vignette-based experimental designs help ‘‘standardize the social stimulus across subjects’’32(p103) and have been used in several studies of patientphysician decision making.33–35 After giving consent on an Institutional Review Board–approved consent form, respondents were asked to imagine visiting their dermatologist to discuss treatment options for a newly diagnosed skin cancer. The DA group was instructed to imagine themselves in the waiting room where clinic staff gave them a printed DA designed to help clarify options available to them to treat basal cell carcinoma. Thereafter, the actual DA appeared on the screen. The DA included an openended value clarification component in which

respondents were asked to consider and write down ways they thought the various treatment options might affect their lifestyle and interact with their value preferences. The DA mentioned the availability of support group assistance. The No DA group was not informed of the specific skin cancer type and was asked to imagine themselves in the waiting room prior to an appointment with their dermatologist to discuss a positive skin cancer diagnosis and testing/treatment options. This group was also instructed to imagine seeing a basic brochure on skin cancer that focused on support group availability, but they received no actual health education material during the vignette experience. Thus, the No DA group was purposely given minimal information about their condition. Furthermore, both the DA and No DA groups were randomized on giving versus receiving support group help, but no significant differences across those groups on outcomes were observed, and the construct was excluded from further analysis. For both pilot and experimental study groups, all scale measures were taken after exposure to their respective vignettes. The No DA group answered questions after reading the vignette, while the treatment group read the vignette, experienced the actual DA, and then answered questions. The DA read by the DA group was developed for the purpose of the study and is not in general use. However, its content was organized along the lines commonly used in DAs and included an overview section on treatment options followed by treatment option preference ranking and value reflection regarding the preferred ranking. In addition, 82% of the DA group felt the amount of information in the DA was ‘‘about right,’’ 92% thought the information in the DA was somewhat or very helpful in preparing them to meet with their physician, and 94% said that they would probably or definitely recommend the DA to a friend in the same situation. Pilot Study Measures Table 1 presents the published sources and summary statistics for measures in both the pilot study and experimental study. Table 2 describes the items that comprised each of the measures used in each study. With the exception of the outcome factor, all latent constructs in the proposed model outlined in Figure 1 were operationalized with 3 to 4 reflective indicators from each scale. Selection of the indicators was based on reliability analysis. All Cronbach’s a for the latent construct indicators in the pilot study are

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higher than 0.70, with the exception of patient empowerment, which was measured with 2 items (Cronbach’s a = 0.62). Pilot Study: Measurement Model Validation and Common Method Bias Assessment By modeling measurement error rather than assuming absence of error, structural equation modeling (SEM) increases statistical power, reduces the likelihood of type II error, and increases the researcher’s ability to identify relationships that might not be found using other generalized linear model approaches.36 In addition, by allowing simultaneous modeling of antecedents, mediators, and outcomes in combination with multigroup comparisons, SEM may help identify and validate latent constructs as well as the direct and indirect processes through which DAs operate. Despite such strengths, SEM can lead to dubious conclusions in the absence of strong theory and attention to validation detail. For this reason, all structural paths proposed in the model shown in Figure 1 were grounded in past research and theory, as described earlier. In addition, precautions were taken to ensure that the model did not suffer from identification problems (e.g., through use of 3 to 4 indicators per factor, use of reflective rather than formative indicators, and proposal of a recursive model).37 A 5-factor measurement model was tested using confirmatory factor analysis (CFA). Thus, all exogenous, mediating, and outcome factors were incorporated into the measurement model. Fit indices suggested that the measurement model exhibited strong fit. Although the x2 fit statistic was significant (study 1: x2[210] = 305, P \ 0.001), given wellknown inflation problems due to large sample size and model complexity,38 other fit indicators were examined, and all of these were acceptable (comparative fix index [CFI] = 0.97; Tucker-Lewis index (TLI) = 0.97; root mean square error of approximation [RMSEA] = 0.03; root mean squared residual [SRMR] = 0.047).38 All factor loadings were significant, and all exceeded 0.55, with most 0.70 or higher. In addition, construct reliabilities were greater than 0.70, with the exception of the empowerment factor with a = 0.62. Average variance extracted (AVE) estimates were greater than 0.50, with the exception of empowerment (0.46) and medical information desire (0.45). Discriminant validity was analyzed by comparing the AVE for each factor to the squared interconstruct correlations (ICs). All AVE estimates were larger than the ICs, indicating discriminant validity. In addition, all correlations between factors were below unity, with absolute

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values ranging from 0.10 to 0.51. Overall, these results indicate that the model exhibited marginally acceptable convergent and adequate discriminant validity.39 Common method bias was investigated using the single unmeasured latent method factor approach following Podsakoff and others.39 Although addition of the method factor improved fit relative to the CFA measurement model, the proportion of variance attributed to method versus trait plus method variance was less than 8%. This result suggests that common method bias, although not completely absent, is unlikely to affect the outcomes significantly. Finally, because the analysis involved comparing structural coefficients between the DA and No DA groups, it was important to test for measurement invariance across the 2 groups to determine whether the measurement models yielded equivalent representations of the same construct.37 Full configural and metric invariance was obtained, meeting requirements for comparison of unstandardized structural model path coefficients across the groups.40 PILOT STUDY: RESULTS Pilot Study: Sample Description The original samples for the pilot study were fairly large (DA group, n = 522; No DA group, n = 413). Such sample sizes are not optimal for SEM, as they tend to bias model fit negatively.39 To address this issue, random samples of approximately 50% from each group were selected (DA group, n = 254; No DA group, n = 215) and used in the SEM analyses. The samples were recruited within a few months of each other, with the DA group taking the survey first, followed by the No DA group. As noted, national panels managed by an established online survey provider were used to recruit participants for the survey. Age difference across the 2 groups was statistically significant (DA, x = 48.0; No DA, x = 52.3; P \ 0.001) but relatively small. Furthermore, white respondents in both groups (88.2% for the DA group v. 81.4% for the No DA group) were relatively overrepresented. In general, the groups were very similar in terms of demographic and other measures (e.g., empathy and perspective taking41; see Table 3). Pilot Study: Structural Model Validation The x2 for the overall structural model depicted in Figure 1 was significant, x2(222) = 367, P \ 0.001. However, this result is not unusual given the large

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Satisfaction with Life Scale

Cancer SelfEfficacy Subscale Cancer SelfEfficacy Subscale Based on Empowerment Literature

Life satisfaction

Cancer comprehension/ participation confidence

Cancer Treatment Attitude

Patient versus cancer empowerment

a. Pilot study. b. Experimental study.

Health Opinion Survey

Scale Name

.81a .84b 0.86a 0.88b 0.62a (r = 0.45) 0.71b (r = 0.55)

Wolf and others (2005)12 Anderson and Funnel (2010)5 Cattaneo and Chapman (2010)6

0.87a 0.87b

0.70a 0.76b

Cronbach’s a

Wolf and others (2005)12

Diener and others (1985)24

Krantz and others (1980)13

Scale Source

4.2 4.0 Disagree (1), agree (5) 3.3 3.4 Describes me: not at all (1)/very Much (5) 3.2 3.3 Disagree (1) Agree (4) 3.0 2.9 Disagree (1), agree (4) 72.5 Power: cancer (1), me (100) 76.5 Cancer: victim (1), victor (100)

Decision Aid Group x

3.1 3.2 Disagree (1) Agree (4) 2.9 2.8 Disagree (1), agree (4) 73.0 Power: cancer (1), me (100) 73.5 Cancer: victim (1), victor (100)

4.3 3.9 Disagree (1), agree (5) 3.2 3.3 Describes me: not at all (1)/very Much (5)

No Decision Aid Group x

P . 0.75 P . 0.12

P . 0.15 P \ 0.02

p..08 p..08

P . 0.30 P . 0.17

P . 0.66 P . 0.42

P Value Difference Test

Pilot Study and Experimental Study: Factor Construct Scales, Cronbach’s a, and Group Comparisons on Means

Desire for medical information

Factor Constructs

Table 1

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Table 2

Survey Measure Items for Structural Equation Model (SEM)

Desire for medical information 1. I usually don’t ask the doctor many questions about what they’re doing during a medical exam. (reverse coded) 2. I’d rather have doctors make the decisions about what’s best for me than for them to give me a whole lot of choices. (reverse coded) 3. It is better to trust the doctor in charge of a medical procedure than to question what they are doing. (reverse coded) Comprehension/participation confidence 1. I am confident in my ability to understand cancer materials. 2. I am confident that I am able to deal with any unexpected health problems. 3. I am confident in my ability to understand my doctor’s instructions. 4. I know that I will be able to actively participate in decisions about my treatment. Cancer attitude 1. I won’t let cancer get me down. 2. It is easy for me to keep a positive attitude about the cancer. 3. It is easy for me to maintain a sense of humor about the cancer. 4. I am confident that I can control my negative feelings about the cancer. Life satisfaction 1. In many ways, my life is close to ideal. 2. The conditions of my life are excellent. 3. I’m satisfied with my life. 4. So far I have gotten the important things I want in life. Self-empowerment versus a cancer diagnosis 1. Now, please think about the balance of power between people who have cancer and the cancer itself. On the scale below, please select the number that best describes where you believe the power lies. 2. Think about the term VICTOR defined as ‘‘a self that is full of possibility of defeating cancer’’ and then the term VICTIM, ‘‘a self that is full of possibility of being defeated by cancer.’’ On the scale below, please select the number that indicates how you would feel about yourself if you were diagnosed with cancer.

sample size and complex model. Other fit statistics suggested that the proposed model fit the data fairly well (CFI = 0.96; TLI = 0.95; RMSEA = 0.04; and SRMR = 0.05). A test for multivariate normality indicated violation of this assumption. As such, violations may affect path coefficient and standard error estimates, and bootstrapping with 2000 trials was undertaken.42 Lack of multivariate normality was

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not found to significantly affect estimates of the path coefficients (details available on request). Thus, the model was determined to be robust. As a final validation check, theoretically plausible competing models were analyzed.40 The proposed model (see Figure 1) was first compared with a fully saturated model featuring all recursive paths. Neither x2 nor the other fit indices improved. A second competing model featured an additional single direct path from patient comprehension/participation confidence to patient empowerment. However, the path was not significant for either group (P . 0.49), and model fit did not improve. A third competing model tested the proposed model without path 1, from desire for medical information to empowerment. This is a reasonable alternative model, as hierarchy of effects theory could be used to predict that desire for medical information will relate to empowerment only indirectly through confidence and attitude. Yet x2 was significantly worse (P \ 0.001), indicating that the alternative model did not fit the data as well as the original. A final model was tested with all paths reversed (e.g., patient empowerment to desire for medical information). This was done to determine whether the overall direction of the model was empirically appropriate. The x2 fit was significantly worse, Dx2(2) = 13, P \ 0.01. This suggests that the overall direction of the paths within the model, based on theoretical considerations, is empirically appropriate. Pilot Study: Structural Model Pretest Given the lack of random assignment to treatment, analysis of the structural model in the pilot study focused on the overall impact of the DA experience (versus No DA) on patient empowerment. If the DA worked as expected, it should have strengthened antecedent relationships (versus No DA), in part by addressing patient needs and mind-sets associated with schema that tend to be activated in the context of decision making regarding cancer treatment with one’s physician. Looking first at the DA group, the standardized total effects of the 4 antecedents on patient empowerment ranged from 0.32 to 0.59. However, the same 4 effects ranged only from 0.10 to 0.32 for the No DA group. Similarly, the squared multiple correlation (akin to R2 in multiple regression)42 for the joint effect of all antecedents on patient empowerment was 0.53 for the DA group but only 0.17 for the No DA group. Finally, the DA experience produced all significant paths (P \ 0.02), while the absence of a DA resulted in 3 nonsignificant paths. Overall,

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Table 3

Pilot Study: Comparison of Decision Aid (DA) Group Versus No DA Group

Variable

Gender (%) Male Female Age (y) White (%) Personal cancer death experience (%) Past cancer treatment (%) Current cancer treatment (%) Empathya (x) Perspective takinga (x)

Group 1 (n = 254): DA Experience

Group 2 (n = 215): No DA Experience

44.1 55.9 48.0 88.2 81.1 11.3 2.8 4.0 3.7

51.2 48.8 52.3 81.4 83.7 15.2 1.9 4.0 3.6

Significance Level

P . 0.12

P \ 0.001 P . 0.05 P . 0.45 P . 0.22 P . 0.52 P . 0.66 P . 0.69

a. Davis (1983); disagree (1)/agree (5) scale.41

these results suggest that the DA may strengthen multiple path relationships within the structural model. However, the pilot study used a nonrandomized design that may have confounded results. In addition, the convergent validity of the measurement model was marginal on 2 constructs (i.e., slightly below 0.50 AVE). Using a randomized experimental design, the main study enabled formal testing of the hypothesized paths between antecedents, mediators, and patient empowerment.

questions. All other measures came after completion of the vignette only (No DA group) or vignette and DA (DA group). Among those who saw the DA, 80% (82% in the pilot) felt the amount of information in the DA was ‘‘about right,’’ 94% (92% in the pilot) thought the information in the DA was somewhat or very helpful in preparing them to meet with their physician, and 94% (94% in the pilot) said that they would probably or definitely recommend the DA to a friend in the same situation.

THE EXPERIMENTAL STUDY: METHODS

Experimental Study: Measures

Experimental Study: Design and Procedures In the experimental study, conducted approximately 1 y later, a single panel sample from the same US online survey provider was recruited. However, this time, respondents were randomly assigned to treatment. Thus, this study replicated the pilot in terms of measures but differed in its use of a randomized experimental design rather than a matched cross-sectional approach. It also differed slightly in the vignette description. Unlike the pilot study, both groups were informed that they were meeting with their dermatologist to discuss treatment options for a recently diagnosed basal cell carcinoma. In addition, the vignette did not address the issue of support group availability. Finally, the No DA group was informed of the availability of magazines and newspapers in the waiting room, while the DA group was told that the nurse took them to a partitioned area where they experienced the DA prior to seeing the physician (see Figure 2). The DA group next saw the actual DA with treatment options, a limited value clarification exercise, and DA evaluation

As in the pilot study, all constructs were based on established scales (see Tables 1 and 2). With the exception of the outcome factor, all latent constructs in the proposed model outlined in Figure 1 were operationalized with 3 to 4 reflective indicators from each scale. Selection of the indicators was based on reliability analysis (all Cronbach’s a . 0.70). Experimental Study 2: Measurement Model Validation and Common Method Bias Assessment Once again, fit indices indicated strong measurement model fit. Although x2 was significant, x2(210) = 263.3, P \ 0.001, other fit indicators were very acceptable (CFI = 0.99; TLI = 0.98; RMSEA = 0.02; SRMR = 0.05). All factor loadings were significant, and all but one (0.53) exceeded 0.60, with most 0.70 or higher. In addition, all construct reliabilities were very close to or greater than 0.70, and all AVE estimates were greater than 0.50. All AVE estimates were larger than the ICs, indicating that the model exhibited discriminant validity. In addition, all correlations between factors were below unity,

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Decision Aid Group Please imagine that you have received a phone call from your dermatologist (skin doctor). During the call, the doctor says that a skin cancer test for a growth on your ear has come back from the lab. The doctor says that it is positive for basal cell carcinoma. Basal cell carcinoma is rarely fatal but without treatment it can become a serious and potentially disfiguring disease. The doctor asks you to come into the office that afternoon to discuss treatment options for the skin cancer. Now, imagine that it is the afternoon and that you have arrived at your dermatologist’s office. The nurse comes out to the waiting room and takes you over to a private area where there is a desk and a computer behind a partition. The nurse asks you to sit down and please click on the screen icon that says Patient Decision Explorer. The nurse tells you that reading the Patient Decision Explorer before you see the doctor will provide you with basic information about different cancer treatment options for basal cell carcinoma. You thank the nurse, sit down and begin to read the Patient Decision Explorer on the computer screen. Please close your eyes now and imagine for thirty seconds the story just outlined. Once you have imagined yourself in the doctor’s waiting room in front of the computer, please click on the button below and move on to read the Patient Decision Explorer. No Decision Aid Group Please imagine that you have received a phone call from your dermatologist (skin doctor). During the call, the doctor says that a skin cancer test for a growth on your ear has come back from the lab. The doctor says that it is positive for basal cell carcinoma. Basal cell carcinoma is rarely fatal but without treatment it can become a serious and potentially disfiguring disease. The doctor asks you to come into the office that afternoon to discuss treatment options for the skin cancer. Now, imagine that it is the afternoon and that you have arrived at your dermatologist’s office. The nurse comes comes to the window and asks you to make yourself comfortable in the waiting room. The nurse points to several magazines and today’s newspaper as items you can read while waiting for your appointment. You thank the nurse and sit down in the waiting room thinking about the appointment you are going to have with the doctor to discuss different treatment options for basal cell carcinoma. Please close your eyes now and imagine for thirty seconds the story just outlined. Once you have imagined yourself looking in the doctor’s waiting room, please click on the button below and move on to answer the questions that follow. Figure 2 Vignettes used in the experimental study.

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Table 4 Pearson Product-Moment Correlation Coefficients: Sum Scores of Items Used in SEM for Experimental Study Comprehension/ Participation Confidence

Desire for medical information Comprehension/participation confidence Cancer attitude Life satisfaction

DA group No DA group DA group No DA group DA group No DA group DA group No DA group

0.141* 0.104

Cancer Attitude

Life Satisfaction

–0.014 –0.010 0.563** 0.373**

–0.173** 0.063 0.230** 0.172** 0.276** 0.178**

Self-Empowerment

0.236** –0.059 0.320** 0.199** 0.456** 0.442** 0.175* 0.236**

*Statistically significant at P  0.05. **Statistically significant at P  0.01.

with absolute values ranging from 0.015 to 0.56. Together, these results indicate that the model has convergent and discriminant validity. Discriminant validity of model constructs is further supported by the Pearson product-moment correlations between sum score variables, reflecting each factor in the structural model (e.g., the simple correlations between cancer attitude and empowerment are less than 0.50 for both the DA and No DA groups; see Table 4). Common method bias was investigated using the single unmeasured latent method factor approach.39 Although addition of the method factor improved fit relative to the CFA measurement model, the proportion of variance attributed to method versus trait plus method variance was less than 3%. Thus, common method bias did not significantly affect the outcomes. Finally, full configural and metric invariance was obtained, enabling comparison of the structural path coefficients across groups.40

EXPERIMENTAL STUDY: RESULTS Experimental Study: Sample Description Random assignment of online panel adults (average age, 52.8 y) resulted in roughly equivalent sized DA (224) and No DA groups (228). The largest difference was in the percentages of white respondents, with 66.5% and 79.8% in the DA and No DA groups, respectively (see Table 5). Overall, however, the groups were very similar in terms of demographic and other measured characteristics (e.g., empathy and perspective taking; see Table 3). Differences across the 2 studies were minor, with the experimental study having a slightly older and somewhat more

ethnically diverse mix of respondents. Thus, the groups within the experimental study are comparable, and the limited number of differences is unlikely to confound estimations of structural path coefficients within the hypothesized model. Experimental Study: Structural Model Validation In the experimental study, the x2 for the overall structural model depicted in Figure 1 was significant, x2(222) = 344, P \ 0.001, but other fit statistics suggested that the proposed model fit the data well (CFI = 0.97; TLI = 0.96; RMSEA = 0.04; and SRMR = 0.05). Once again, the test for multivariate normality indicated violation of this assumption and, hence, bootstrapping with 2000 trials was undertaken.42 Lack of multivariate normality was not found to significantly affect the path coefficients (details available on request). Thus, the model was determined to be robust. Competing model analysis produced results that were very similar to those obtained in the pilot. For example, a competing model with an additional direct path from patient comprehension/ participation to empowerment did not improve fit, and the paths for both groups were not significant (P . 0.58). In addition, a competing model with all paths reversed (e.g., comprehension/participation confidence to desire for medical information) resulted in significantly worse fit, Dx2(2) = 22, P \ 0.01, suggesting that the overall direction of the paths as indicated by theory was appropriate. Given support for the proposed model’s convergent, discriminant, nomological validity as well as minimal common method bias, hypothesized paths 1 to 7 were tested for main effect and multigroup comparative statistical significance.

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Table 5

Experimental Study: Comparison of Decision Aid (DA) Group Versus No DA Group

Variable

Group 1 (n = 224): DA Experience

Group 2 (n = 228): No DA Experience

50.4 49.6 52.6 66.5 83.0 7.2 1.3 4.0 3.6

48.7 51.3 53.1 79.8 84.0 12.7 0.4 4.0 3.7

Gender (%) Male Female Age (y) White (%) Personal cancer death experience (%) Past cancer treatment (%) Current cancer treatment (%) Empathya (x) Perspective takinga (x)

Significance Level

P . 0.26

P . 0.43 P \ 0.001 P . 0.83 P = 0.053 P . 0.31 P . 0.79 P . 0.37

a. Davis (1983): disagree (1)/agree (5) scale.41

Experimental Study: Structural Path Analysis Path 1 from desire for medical information to patient empowerment was statistically significant for the DA group (P \ 0.001) but was insignificant for the No DA group (P . 0.43; see Figure 3 and Table 6). In addition, as hypothesized, the DA experience significantly strengthened the relationship between desire for medical information and empowerment (P \ 0.001). Path 2 from desire for medical information to comprehension/participation confidence was statistically significant (P \ 0.01) for the DA group and marginally significant (P . 0.06) for the No DA group. However, the moderating effect of the DA experience on this path was not significant (P . 0.05). At the same time, the DA experience produced a significantly higher structural path 3 coefficient, from comprehension/participation confidence to cancer attitude (P \ 0.01). Finally, path 4 between cancer attitude and empowerment was significant for both groups (P \ 0.001), but there was no DA moderation effect. Turning to the life satisfaction paths, paths 5 and 6 (but not 7) were significant and in the predicted positive direction for the DA group. For the No DA group, paths 5 and 7 (but not 6) were significant and in the expected direction. However, the DA experience did not strengthen any of these paths. Looking within the DA group at total, direct, and indirect standardized effects on patient empowerment, all 4 antecedents had similar total effects between 0.30 and 0.40 as in the pilot study. However, the direct effect of desire for medical information (0.31) on empowerment (path 1) was larger than its indirect effect through confidence and cancer attitude (0.20; paths 2, 3, 4). The indirect effect of confidence on empowerment was considerably larger (0.34; paths 3, 4). Thus, desire for medical

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information had a stronger direct effect than indirect role. For life satisfaction, the opposite was observed. This construct’s indirect effect on empowerment through confidence and cancer attitude (0.35; paths 5, 3, 4, and 6, 4) was substantially stronger than its direct effect (0.12; path 7). Overall, the DA versus No DA experience significantly strengthened and therefore moderated 2 paths (paths 1, 3). In addition, while 1 nonsignificant path was found in the DA group (path 7), 3 were found in the No DA group (paths 1, 2, and 6). Although moderation effects cannot be assumed using comparison of significant versus nonsignificant path coefficients,43 the possibility of increased accessibility to schema hypothesized as important to patient empowerment is suggested by finding more significant paths in the DA group. Furthermore, the squared multiple correlation coefficient for empowerment was substantially higher for the DA group (0.48) than for the No DA group (0.31). DISCUSSION The studies discussed herein appear to represent one of the first investigations into a nomological net of underlying psychological antecedents and mediators of patient empowerment in the context of a DA for cancer treatment decision making. Theory-based model specification, a matched sample pilot test followed by a randomized experimental study, coupled with extensive validity tests, measurement invariance analysis, and tests of competing models increase confidence in the results presented in this article. An important finding that emerges from both studies is that the DA experience exerted a positive impact on the antecedent and mediating antecedents

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DECISION AIDS AND PATIENT EMPOWERMENT IN CANCER TREATMENT

Table 6

Unstandardized/Standardized Structural Path Coefficients Experimental Study (Unstandardized/Standardized Path Coefficients)

SEM Path

Decision Aid Group

Path 1: Desire for information to self-empowerment Path 2: Desire for information to comprehension/ participation confidence Path 3: Comprehension/participation confidence to cancer attitude Path 4: Cancer attitude to self-empowerment Path 5: Life satisfaction to comprehension/ participation confidence Path 6: Life satisfaction to cancer attitude Path 7: Life satisfaction to self-empowerment

No Decision Aid Group

4.56/0.307** –1.17/–0.055a b Critical ratio ; P \ 0.001 0.113/0.210** 0.104/0.144a Critical ratio nonsignificant 0.729/0.601** 0.403/0.409** Critical ratio; P \ 0.01 12.96/0.570** 14.84/0.493** Critical ratio nonsignificant 0.134/0.268** 0.114/0.207** Critical ratio nonsignificant 0.102/0.168** 0.043/0.079a Critical ratio nonsignificant 1.59/.116a 3.01/.183** Critical ratio nonsignificant

**P \ 0.01. a. Path not significant, P . 0.05. b. Critical ratios test for significant differences in path coefficients across groups. Significance indicates moderation by the groups (Byrne 2001, p 241).42

Figure 3 Experimental study: multigroup SEM results.

to patient empowerment. Furthermore, in the experimental study, which enabled multigroup testing of treatment versus control groups, the DA experience interacted with patients’ desire for medical information to positively strengthen empowerment directly and indirectly through cancer attitude. In addition, the fact that the DA experience resulted in more

statistically significant structural path relationships (i.e., 13/14 v. 8/14 statistically significant path coefficients for the DA/No DA groups in the 2 studies combined) suggests the possibility of a network of DArelated effects on relevant schema accessibility that should be investigated in subsequent research. A final indicator of an overall DA moderating effect in

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both studies is the fact that the predictors of empowerment explained 53% (48%) of the variance for the DA group versus 17% (31%) of the variance for the No DA group in the pilot study (experimental study). Thus, the overall pattern of both studies’ results, coupled with tests of the hypothesized structural paths in the experimental study, supports the conclusion that the DA experience positively strengthened the effects of SDM antecedent and mediating constructs on patient empowerment. This is not the case for the direct and indirect influences of the broader psychological construct, life satisfaction, on patient empowerment. In the experimental study, experiencing a DA did not significantly strengthen the direct or indirect paths between these 2 constructs. However, the pattern of results in the experimental study suggests some interesting possibilities. Specifically, it appears that the DA experience positively affected empowerment by satisfying the desire for medical information, which had both significant direct (path 1) and indirect effects through comprehension/participation confidence and cancer attitude (path 3). The indirect path effects through comprehension/participation confidence and cancer attitude were further strengthened by life satisfaction for the DA group (paths 5, 6). Only 1 of the 2 indirect paths was significant for the No DA group (path 5). However, the direct effect of life satisfaction on empowerment (path 7) was significant only for the No DA group. While these results do not confirm additional moderation effects, they do suggest the possibility that the DA experience may channel individual difference effects on empowerment through antecedents to SDM, whereas not having a DA experience may lead to less reliance on such antecedents. Additional research that clarifies the nature and extent of these relationships is clearly warranted. For example, the processes through which the DA experience heightened patient empowerment both directly and indirectly through comprehension/ participation confidence and cancer attitude are unclear. Did this result occur simply from felt congruency between the contextually stimulated need for medical information and availability of that information in the DA, or was felt congruency accompanied by actual increases in knowledge or some other unidentified mediator? A related question involves directionality of the downstream SDM constructs, specifically comprehension/participation confidence, cancer attitude, and patient empowerment. Although in both studies, measurement model analysis supported convergent and discriminant validity

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for the 3 constructs and competing model analysis supported the overall directionality of the theorybased nomological network, it is important to not rule out at this early stage varying possibilities such as simultaneous activation of multiple SDM schema and/or nonrecursive (feedback) relationships. Future research should investigate specific paths to confirm or modify the associations specified in the model. In addition, respondents who viewed the DA in the experimental study did not undertake a full value clarification activity, as is often featured in DAs.44 Experiencing deeper value clarification as part of the DA experience may increase accessibility to broader sets of value schema, including overall life satisfaction. Future studies could investigate whether a formal value clarification exercise produces more consistent positive main and moderating effects, as originally hypothesized and as established in the case of desire for medical information. In addition, value-related research involving other ethnic groups appears particularly important to determining the generalizability of the studies’ findings.45 Furthermore, future research should include constructs such as preference for SDM,46 as these appear likely to play important antecedent roles in understanding the effects of DA experience on patient empowerment. Autonomy preference47 was originally planned for inclusion in the overall model as an exogenous individual difference predictor. However, serious measurement problems prevented its use in the model. These problems may have been due to a lack of variance on the measure, as few respondents preferred the ‘‘patient decides’’ end of the scale.47 It is also possible to imagine certain contextual antecedents that would lead patients to prefer not to use a DA. For example, individuals who are highly independent48 or who perceive themselves as having very limited time49 may feel disempowered by the DA experience. Thus, it is important for future researchers to consider a broader range of antecedents, including those that may suggest possible negative effects for certain types of patients who experience a DA. Finally, despite widespread use and general acceptance of vignettes as a valid preliminary approach in health-related research,33–35 it is important to test the proposed model in a clinical context. Analysis of respondent thought listings in both the DA and No DA groups suggests that participants actively imagined how they would think and feel in the situations described in the vignettes. Yet research in clinical settings is necessary to ensure the external validity of the proposed model.

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DECISION AIDS AND PATIENT EMPOWERMENT IN CANCER TREATMENT

A final important topic for future research involves further study of relationships between patient empowerment and SDM. Theory strongly suggests that an empowered patient is more likely to desire higher levels of engagement with his or her physician.50,51 However, the experimental study discussed herein does not explicitly test this prediction. Future research could include a latent factor with multiple indicators to determine the extent to which stronger antecedent and mediating relationships between traditional SDM constructs and empowerment tested in the experimental study lead to higher willingness to engage one’s physician in ways consistent with the SDM model.52–54 In this case, patient empowerment could be modeled as the central mediator between upstream constructs and desired level of SDM. In sum, outcome-focused DA research is clearly important and should continue, particularly with respect to identifying longer-term outcome influences.55 In both the pilot and experimental studies, the DA experience positively affected patient empowerment. Furthermore, by testing relationships between a system of antecedents and mediators to patient empowerment through multigroup SEM and a randomized experimental design, increased understanding of the complex processes underlying DA effects is possible. Such theory-based models appear likely to increase the field’s understanding of patient processing of DA information—understanding that is critical to increasing patient empowerment as well as SDM between patients and their health care providers. ACKNOWLEDGMENTS The author thanks the editor-in-chief of Medical Decision Making (MDM), Alan Schwartz, and the 3 MDM reviewers for their insightful recommendations regarding opportunities to strengthen the article’s contribution to our field. I also appreciate the efforts of Qimei Chen, PhD, and Jennifer Aaker, PhD, who helped develop some of the questions used in the pilot and experimental studies. In addition, I thank my research assistant, John Friend, PhD, for his considerable efforts during the revision process. Finally, I would like to express my appreciation of the contributions of the many survey participants whose thoughtful responses were evident in both studies.

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