doi: 10.1111/hex.12257
Shared decision making in patients at risk of cancer: the role of domain and numeracy Yaniv Hanoch PhD,* Talya Miron-Shatz PhD,† Jonathan J. Rolison PhD,‡ Zehra Omer BA§ and Elisa Ozanne PhD¶ *Associate Professor, School of Psychology, Cognition Institute, University of Plymouth, Drake Circus, Plymouth, UK, †Associate Professor, Center for Medical Decision Making, Ono Academic College, Kiryat Ono, Israel, ‡Assistant Professor, School of Psychology, Queen’s University Belfast, Belfast, UK, §Research Associate, Massachusetts General Hospital–Institute for Technology Assessment, Boston, MA, and ¶Associate Professor, The Dartmouth Institute Geisel School of Medicine at Dartmouth, Centerra Parkway, Lebanon, NH, USA
Abstract Correspondence Yaniv Hanoch, PhD University of Plymouth, School of Psychology, Cognition Institute, Drake Circus, PSQ B204, Plymouth, UK, PL4 8AA E-mail: [email protected] Accepted for publication 6 August 2014 Keywords: cancer, objective numeracy and subjective numeracy, shared decision making
Background Shared decision making has become an integral part of medical consultation. Research has, however, reported wide differences in individuals’ desires to be involved in the decision-making process, and these differences in preferences are likely to be the result of a number of factors including age, education and numeracy. Objective To investigate whether patients at genetic risk for cancer had preferences for shared decision making that differed depending on medical domain (general health vs. cancer) and whether decision preferences are linked to numeracy abilities. Methods Four hundred and seventy-six women who consented to participate in response to an email sent by a local branch of the U.S.-based Cancer Genetics Network (CGN) to its members. Participants completed the Control Preference Scale, as well as an objective and subjective numeracy scales. Results Decision domain (cancer vs. general health) was not associated with women’s preferences for involvement in decision making. Objective and subjective numeracy predicted a preference for decision involvement in general, and only objective numeracy was predictive with regard to cancer. Conclusion Participants were equally likely to state they wanted to play an active, collaborative or passive role in both medical domains (general and cancer). High-numeracy participants were more likely to express a desire for an active role in general and in case they were diagnosed with cancer. Practice implications Health authorities’ recommendations to clinicians to include patients in their medical decisions are supported by patients’ desires, and clinicians should be cognizant of their patients’ preferences as well as their numeracy skills.
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Introduction Shared decision making has become an integral part of medical consultation. National health organizations1,2 in the United States, for example, recommend the inclusion of patients in the decision-making process. Indeed, with an increase in health consumerism and the availability of medical information over the Internet, patients have assumed a greater role in managing their health.3 Research4 has, however, reported wide differences in individuals’ desires to be involved in the decision-making process, and these differences in preferences are likely to be the result of a number of factors including age, education and numeracy. While health-care providers have been advised to ensure shared decision making, systematic reviews have highlighted the heterogeneity of patients’ desires regarding this recommendation. One early review5 showed that although a majority of individuals wished to be informed about their illness, the responses were much more varied when individuals were asked about their desire to be actively involved in the treatment decision. In fact, a substantial minority wished to have a passive role, leaving treatment decisions to their doctor. Other reviews6,7 reported similar findings, with an additional investigation8 indicating that 21% of studies show that participants wanted to delegate the decision to their health-care provider. Other studies likewise revealed inconsistencies, with some9–11 reporting a high percentage of participants expressing a desire to have an active or shared role in their treatment decision and others12–14 finding a substantial proportion preferring a passive role in the decision process. Why does the literature present such a mixed picture? Two methodological factors can help explain these divergent results. First, researchers have studied different populations: Some14 have focused on the general public, others15–18 have narrowed their investigations to specific patient populations, and a third group has compared patients with the general population.12,19 In one illustrative study, researchers20 found a schism between the preferences of patients with cancer
and those of the general population regarding involvement in their medical treatment. Although only 12% of the patients with cancer indicated a wish to have an active role in choosing their medical treatment, the rate increased dramatically to 64% among general households. Second, researchers have shown that the nature of the disease affects the level and extent of patients’ desires for involvement. One study14 found that individuals suffering from a chronic disease (e.g. diabetes) were more than twice as likely (31% vs. 12%) as patients with cancer to prefer an active role. Others12 showed that as their medical conditions became graver, individuals preferred to defer treatment decisions to their health-care provider (e.g. for breast patients with cancer).21 There is growing interest in identifying factors that might be associated with the preference for active versus passive (or handing over the decision to the attending physician) shared decision making. Earlier studies largely identified a range of factors – age, education, health literacy, ethnicity and having a regular physician – as important predictors. Early findings20 revealed that age was inversely related to the desire to experience shared decision making, with older participants (both patients with cancer and general household participants) preferring to refer decisions to their physicians. In a large cross-sectional survey with over 3000 participants, researchers22 found that socioeconomic and demographic factors (i.e. ethnicity) and having a regular physician were linked with individuals’ preference for shared decision making. Those with low-income and African American ethnicity were much more likely to favour handing over the decision making to the physicians. An earlier literature review5 identified minority ethnic affiliation, sickness level, age and education as factors that could impede the desire for shared decision making.7,23 While researchers have focused on the above factors, numeracy skills, although shown to be vital in many health-related decision making, have received scant attention. This is surprising, as researchers have long been aware of the important role numeracy plays in different
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medical decisions.24 A large corpus of data revealed an association between low numeracy skills and poorer comprehension of screening information,25 lack of familiarity with the health-care structure,26 and worse health outcomes.27 Of equal importance, it has also been argued that numerical abilities are independent of IQ and education level.28 Indeed, Reyna and colleagues28 stated that ‘on the basis of studies that have controlled for education, intelligence, literacy, and other factors, we can be reasonably sure that numeracy is a separate faculty’ (p. 967). In support of this argument, Wood and colleagues29 found that numeracy predicted performance on a medical insurance decision task independently of other cognitive variables or education, and Brown and colleagues30 showed that numeracy is the key factor in individuals’ ability to interpret graphical breast cancer risk estimates. Based on their own and others’31 findings, it has been argued30 that although the assumption that health literacy and education are related to numerical ability seems intuitively appealing, research repeatedly reveals that education level does not predict numeracy. Historically, numeracy has been measured using objective scales.32 Researchers33 have come to argue that objective numeracy scales (ONS) have a number of shortcomings, such as participants’ dislike of the tests, low completion rates, and that they are difficult to complete over the phone or Internet. Fagerlin and colleagues have developed an alternative measure – known as the subjective numeracy scale (SNS) – as a mean to examine numeric abilities without the above drawbacks. The SNS, in contrast to ONS, only gauge individuals’ perceived ability to deal with mathematical tasks and preference for the use of numerical versus prose information.32,33 Since its publication, a number of studies have validated the SNS among different groups34,35 and have shown that it is faster and easier to administer, offers a more positive experience, has higher completion rates, and can more easily be administered over the phone and Internet.32 In this study, we have included the SNS to examine whether it can help predict
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preference for shared decision making, and serve as a possible alternative for ONS. We had two goals in this study: (i) to determine whether patients at genetic risk for cancer had preferences for shared decision making that differed in two different medical domains: cancer and general health and (ii) to examine the association between both objective numeracy and subjective numeracy abilities and decision preference.
Methods Study participants A total of 1007 women were contacted via an email circulated by a number of local branches of the Cancer Genetics Network (CGN; Table 1) to complete an online survey. Four hundred and seventy-seven women (47% response rate) consented to participate in the study (http://www.cancergen.org/). Only unaffected women at increased risk for breast cancer participated in the study. The inclusion criteria were having at least one relative diagnosed with breast cancer at age 45 or younger, having two or more relatives diagnosed with breast cancer at age 50 or younger, having at least one relative diagnosed with ovarian cancer or having at least one relative diagnosed with male breast cancer. The CGN is a U.S. network of centres that serves as a resource for investigators conducting research on the genetic basis of human cancer susceptibility, integration of this information into medical practice, and behavioural, ethical and public health issues associated with human genetics. A core data set is available on each registrant and contains information on sociodemographic characteristics (although it lacks income information). Participants in this study were recruited and registered on the CGN database by local hospital clinics. They initially provided CGN with baseline data including demographics, family history and disease history. After obtaining consent from all study participants, we extracted an unidentified data set containing
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2802 Shared decision making and numeracy, Y Hanoch et al. Table 1 Demographic (N = 476) Characteristic
Characteristics
of
Participants
their demographic, family and disease history data from the CGN database for analysis.
Value
Duke 40 (8.4%) Emory 25 (5.3%) John Hopkins 74 (15.5%) MD Anderson 25 (5.3%) University of North Carolina 26 (5.5%) University of Utah 129 (27.1%) Colorado 157 (33.0%) Age Mean (SD) 50.5 (7.4) Range 30–61 Education High school or less 29 (6.1%) Some college 105 (22.1%) College graduate 342 (71.8%) Marital status Not married or living together 107 (22.5%) Married or living together 369 (77.5%) Race Asian 3 (0.6%) Black or African American 6 (1.3%) White 454 (95.4%) More than one race 5 (1.1%) Other 5 (1.1%) Unknown or not reported 3 (0.6%) Of Ashkenazi or Eastern European Jewish descent No 418 (87.8%) Yes 46 (9.7%) Unknown 12 (2.5%) Tested for BRCA1/2 gene alterations No 39 (8.2%) Yes 91 (19.1%) Not reported 346 (72.7%) Family member tested for BRCA1/2 gene alterations No 132 (27.7%) Yes 34 (7.1%) Not reported 310 (65.1%) Number of family members with ovarian or breast cancer One 107 (22.5%) Two 97 (20.4%) Three 83 (17.4%) Four 49 (10.3%) Five 26 (5.5%) Six 21 (4.4%) Seven 12 (2.5%) More than seven 11 (2.3%) Not reported 70 (14.7%) Objective numeracy (SD) 1.73 (0.87) Subjective numeracy (SD) 4.70 (0.84) Objective numeracy and subjective numeracy data were missing for three and seventeen participants, respectively.
Study measures The study protocol was approved by the appropriate institutional review boards, and prior to the start of the study, all participants consented to participate in the study. Respondents were informed that the survey would take an estimated 30 min. They were asked to answer a number of questions about shared decision making and objective and subjective numeracy as well as provide demographic information. They were offered the option of receiving a $30 gift card and were not required to answer any question that made them uncomfortable. Shared decision making To study preferences for shared decision making, we utilized one of the most frequently used shared-decision-making measures, the Control Preference Scale.13 The measure asked participants about their (i) desire for involvement in decisions in general, and (ii) their desire for involvement if they were to be diagnosed with breast cancer. The two questions, thus, were designed to probe participants’ preference for shared decision making in general and in regard to cancer. Our measure was adapted from the original study11 where participants were asked to rank the five possible answers; in our case, they were instructed to choose the one answer that best reflected their preference. The precise wording was as follows: Questions: 1. When thinking about the interactions with their doctor, women have different opinions about who should make treatment decisions. Please select one of the following five statements that best reflects your preference for decision involvement in general. 2. When thinking about the interaction with their doctor, women have different opinions about who should make treatment decisions. This might be especially the case with breast
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cancer. Please select one of the following five statements that best reflects your preference for decision involvement if you were to be diagnosed with breast cancer. Responses: A I prefer to make the final selection about which treatment I will receive. B I prefer to make the final selection of my treatment after seriously considering my doctor’s opinion. C I prefer that my doctor and I share responsibility for deciding which treatment is best for me. D I prefer that my doctor make the final decision about which treatment but seriously consider my opinion. E I prefer to leave all decisions regarding treatment to my doctor. Numeracy Objective and subjective numeracy: Respondents completed one of the most extensively used and valid measures of numeracy skill.31 The three-item objective numeracy scale evaluates individuals’ understanding and ability to solve three basic probability and related ratio problems (e.g. ‘Imagine that we flip a fair coin 1000 times. What is your best guess about how many times the coin would come up heads in 1000 flips?’). The measure has been used in hundreds of studies, with a diverse set of population, in wide spectrum of medical decision making, and its psychometrics properties are well established. In addition, an extensive review of the literature28 did not indicate that other, more extensive measures necessarily confer any specific advantage over the more parsimonious31 scale. Each question was scored as correct (coded ‘1’) or incorrect (coded ‘0’). Individual item responses and total number correct were analysed. Following earlier work,34 we have added the scores for each of the three questions and have treated this numeracy score as a continuous variable that ranges from 0 to 3. Participants completed the Subjective Numeracy Scale (SNS),32 a self-report measure of
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perceived ability to perform various mathematical tasks and preference for the use of numerical rather than prose information. The 8-item scale consists of four questions asking respondents to assess their numerical ability in different contexts (e.g. calculating a 15% tip) and four questions asking them to state their preferences for the presentation of numerical and probabilistic information (e.g. preference for percentages vs. words in a weather forecast). Each item is scored on a 6-point Likert scale. The overall SNS score was computed as the average rating across all eight questions. Analysis strategy Logistic regression analyses were conducted on women’s responses to the shared-decisionmaking items. These analyses were performed separately on women’s preferences for decision involvement in general and for decision involvement if they were to be diagnosed with breast cancer. Education and marital status were included as categorical predictors, with age and numeracy included as continuous predictors. Whether women had previously been tested for BRCA1/2 gene alterations and whether a family member had previously been tested for BRCA1/2 gene alterations were included as additional categorical predictors. Objective numeracy was replaced with subjective numeracy ratings in a separate regression model controlling for age, education and marital status. McNemar’s test for repeatedmeasures nominal data was used to test whether women’s preferences for shared decision making in general changed when they imagined that they were diagnosed with breast cancer.
Results Provided in Table 2 are the women’s preferences for decision involvement grouped as ‘active’ (Responses A and B), ‘collaborative’ (Response C) or ‘passive’ (Responses D and E) (see also Fig. 1). Few women (preference in general = 5.9%, preference if diagnosed with
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Shared decision making and numeracy, Y Hanoch et al. Table 2 Women’s Preferences for Decision Involvement in General and if they were to be diagnosed with Breast Cancer (N = 476) Role Characteristic Preference in general Overall (N = 476) Education High school or less (n = 29) Some college (n = 105) College graduate (n = 342) Marital status Not married or living together (n = 107) Married or living together (n = 369) Objective numeracy* (SD) Subjective numeracy (SD) Preference if diagnosed with breast cancer Overall (N = 476) Education High school or less (n = 29) Some college (n = 105) College graduate (n = 342) Marital status Not married or living together (n = 107) Married or living together (n = 369) Objective numeracy (SD) Subjective numeracy (SD)
Active
Collaborative
262 (55.2%)
185 (38.9%)
28 (5.9%)
16 (55.2%) 59 (56.2%) 187 (54.8%)
11 (37.9%) 43 (41.0%) 131 (38.4%)
2 (6.9%) 3 (2.9%) 23 (6.7%)
57 205 1.82 4.77
45 140 1.59 4.59
(53.3%) (55.7%) (0.83) (0.86)
(42.1%) (38.0%) (0.89) (0.78)
Passive
5 23 1.93 4.79
(4.7%) (6.3%) (0.86) (0.94)
258 (54.5%)
175 (37.0%)
40 (8.5%)
15 (51.7%) 60 (58.3%) 183 (53.7%)
14 (48.3%) 39 (37.9%) 122 (35.8%)
0 (0.0%) 4 (3.9%) 36 (10.6%)
59 199 1.80 4.73
40 135 1.60 4.63
(55.7%) (54.2%) (0.84) (0.89)
(37.7%) (36.8%) (0.90) (0.76)
7 33 1.90 4.90
(6.6%) (9.0%) (0.87) (0.73)
Numeracy scores could range between 0 and 3. ‘Preference in general’ data were missing for one participant, ‘preference if diagnosed with breast cancer’ data were missing for three participants, and objective numeracy data were missing for three participants.
*
Preference for decision involvement (%)
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100 90 80
Women's preferences for decision involvement Women’s preference for decision involvement in general Women’s preference for decision involvement if they were to be diagnosed with breast cancer
70 60 50 40 30 20 10 0
Activer role
Collaborative role
Passive role
Figure 1 Women’s preferences for decision involvement in general and if they were to be diagnosed with breast cancer. Error Bars are 95% confidence intervals.
breast cancer = 8.5%) indicated a preference for a passive role. Thus, we focused our logistic regression analyses on whether or not women
had a preference for an active role. As only a minority of women reported that they had previously been tested for BRCA1/2 gene alterations or had a family member who had previously been tested, we included previous testing as additional categorical predictors in our regression analysis in a second block. Higher objective numeracy significantly predicted women’s preference for active decision involvement in general (OR = 1.30; 95% CI: 1.05–1.62; P = 0.017). Effects of objective numeracy are displayed in Fig. 2 (low numeracy = score 0–1, high numeracy = score 2–3). Subjective numeracy ratings were included in a separate regression model as they were highly correlated with women’s objective numeracy scores (r = 0.34, P < 0.001). Subjective numeracy predicted women’s preference for active decision involvement in general (OR = 1.26; 95% CI: 1.01–1.58; P = 0.045). Effects of subjective numeracy are shown in Fig. 2 at low
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100
Low objective numeracy (N = 165)
90
High objective numeracy (N = 307)
80 70 60 50 40 30 20 10 0
Active role
100
Collaborative role
Low subjective numeracy (N = 196)
90
High subjective numeracy (N = 262)
80 70 60 50 40 30 20 10 0
Active role
Collaborative role
100
Passive role
Women's preferences for decision involvement if they were to be diagnosed with breast cancer Low objective numeracy (N = 165)
90
High objective numeracy (N = 307)
80 70 60 50 40 30 20 10 0 Active role
Passive role
Preference for decision involvement (%)
Preference for decision involvement (%)
Preference for decision involvement (%)
Women's preferences for decision involvement in general
school or less, OR = 1.16; 95% CI: 0.73–1.84; P = 0.523), and whether women had previously been tested for BRCA1/2 gene alterations (vs. not previously tested; OR = 0.60; 95% CI: 0.19–1.91; P = 0.385) and whether a family member had previously been tested for BRCA1/2 gene alterations (vs. not previously tested; OR = 1.23; 95% CI: 0.46–3.33; P = 0.684), included in a second block, also did not significantly predict women’s preferences. When women imagined that they had been diagnosed with breast cancer, higher objective numeracy was a significant predictor
Preference for decision involvement (%)
(below the mean rating) and high (above the mean rating) levels. Objective numeracy did not significantly predict women’s preference when included with subjective numeracy in the same regression model (OR = 1.22; 95% CI: 0.97–1.55; P = 0.094), suggesting that subjective ratings capture a large portion of variance in numerical ability. Age (OR = 1.01; 95% CI: 0.98–1.03; P = 0.675), marital status (married or living together vs. not married or living together; OR = 0.92; 95% CI: 0.59–1.42; P = 0.701) and education (some college vs. high school or less, OR = 1.12; 95% CI: 0.51– 2.42; P = 0.783; college graduate vs. high
Collaborative role
Passive role
100 Low subjective numeracy (N = 196)
90
High subjective numeracy (N = 262)
80 70 60 50 40 30 20 10 0
Active role
Collaborative role
Passive role
Figure 2 Women’s preferences for decision involvement in general and if they were to be diagnosed with breast cancer displayed separately for women of high and low levels of objective and subjective numeracy. Error Bars are 95% confidence intervals.
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(OR = 1.26; 95% CI: 1.01–1.56; P = 0.038) of preference for active decision involvement (Fig. 2). Subjective numeracy ratings, included in a separate regression model, did not significantly predict women’s preferences (OR = 1.08; 95% CI: 0.86–1.35; P = 0.510). Age (OR = 1.01; 95% CI: 0.98–1.03; P = 0.524), marital status (married or living together vs. not married or living together; OR = 1.02; 95% CI: 0.66–1.58; P = 0.930) and education (some college vs. high school or less, OR = 1.01; 95% CI: 0.47–2.18; P = 0.980; college graduate vs. high school or less, OR = 1.38; 95% CI: 0.87–2.19; P = 0.177), and whether women had previously been tested for BRCA1/2 gene alterations (vs. not previously tested; OR = 0.82; 95% CI: 0.26–2.59; P = 0.738) or a family member had previously been tested for BRCA1/2 gene alterations (vs. not previously tested; OR = 1.12; 95% CI: 0.42–2.97; P = 0.821) included in a second block, again did not significantly predict women’s preferences. Eighty-four (18%) of the 476 women changed their preferences when asked to imagine they had been diagnosed with breast cancer. For these women, there was no dominant strategy for switching: A fairly even number switched from preferring an active role for general decisions to a collaborative role when they imagined they had breast cancer (32 of 84; 38%) and from preferring a collaborative role for general decisions to an active role when they imagined they had breast cancer (26 of 84; 31%). McNemar’s test confirmed no significant association between switching of preferences from an active to a collaborative role and vice versa (P = 0.511). A minority of the women switched from preferring an active role to a passive role (2 of 84; 2%), or from preferring a collaborative role to a passive role (17 of 84; 20%) when they imaged they had breast cancer, and few women switched from preferring a passive role to a collaborative role (3 of 84; 4%), or from preferring a passive role to an active role (4 of 84; 5%) when they imaged they had breast cancer.
Discussion and conclusion Discussion Current trends encourage the engagement of patients in medical decision making. It is therefore no wonder that researchers and oncologists have been interested in patients’ preferences and decision-making style,30,37,38 as well as in the underlying factors that are linked to patients’ desire for involvement in their treatment decision making. In this study with a large cohort of women at high risk for breast and ovarian cancer, we found, first, that decision domain (cancer vs. general health) did not affect preferences for involvement in decision making. That is, participants were as likely to state they wanted to play an active, collaborative or passive role in their treatment decisions in general as they were in decisions about cancer treatment. This result was unexpected, as earlier studies20 reported that patients with cancer expressed reduced desire to be involved in their medical treatment compared with the general population. Furthermore, others12 have found an inverse relationship between illness severity and a desire for shared decision making. One study21, in fact, found response variation among patients with cancer: those with more severe cancer diagnosis were more likely to defer the decision to their health-care providers. This line of research would suggest a greater desire to be involved in general health decisions compared with cancer-related decisions. Another possibility for our results could rest with the fact that the questions were hypothetical in nature. Indeed, while one systematic review8 has shown that the Control Preference Scale, the instrument used in the current study, is the most frequently used scale, another systematic review4 found that many studies using the Control Preference Scale have revealed a gap between peoples’ preference and their actual involvement. In 19 of the 22 studies included in the systematic review, people expressed greater preference for involvement that actually took place. As such, future
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studies should attempt to measure whether stated preferences are a reasonable predictor of actual behaviour. To our knowledge, ours is the first study to focus on whether women at risk for breast and ovarian cancer express different desires depending on the type of medical (general vs. cancer) condition they face. In other words, in this study, we focused on the domain (cancer vs. general health) within individuals, rather than compare across different populations. Our results indicate that the decision domain made little difference and that the majority of the women would prefer to have either an active or a collaborative role regardless of the magnitude or severity of the decision. That said, 84 of our participants (about 18%) did change their preference depending on the decision domain. Preference changes were, however, inconsistent, as a similar proportion of the women changed from active to collaborative as from collaborative to active. Few women changed their preferences from an active or collaborative role to a passive one. Other factors, not included in our analysis, might also contribute to women’s preference change. It has been shown, for instance, that ethnicity and income are associated with women’s preferences for either a shared or a more passive decision style. It is possible that ethnic minority, less educated and low-income individuals might have exhibited a more pronounce preference reversal. Furthermore, earlier studies36 found that disease severity is associated with decreased desire for being involved in the decision-making process. Given that our sample was at risk but unaffected, we are unable to tell whether disease severity would have altered our results. Finally, it is possible that general health concerns and cancer-specific concerns overlapped to a very large degree, at least in this sample. Our data, furthermore, have important clinical implications. Physicians should be aware that women at risk for breast and ovarian cancer sometimes do change their preferences and that forecasting women’s decision preferences is difficult. Physicians, therefore, who encoun-
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ter this specific population of patients need to ensure that they invest time and effort to verify a woman’s preference on each occasion. Health-care professionals should also be cognizant of their patients’ preferences and refrain from assuming that when dealing with severe illness, patients will not want to be involved in their treatment decisions. Indeed, our data clearly show that women want to take an active role in their treatment decisions. Thus, professionals are encouraged to elicit women’s preferences for involvement in treatment and to actively inquire about the degree to which these preferences generalize across domains. Our sample was composed of well-educated white women at risk for breast and ovarian cancer. In addition, all participants had at least one relative who had been diagnosed with breast or ovarian cancer. As such, the high percentage of participants who expressed a desire to play an active role could represent a ceiling effect. That is, being at high risk for developing breast or ovarian cancer and having relatives who were diagnosed with breast or ovarian cancer could have played a major part in their desire to have an active role. In other words, this group of women had probably given the topic much thought and might have capitalized on their relatives’ experiences with the medical profession. Our results, furthermore, provide support to previous research showing that being female23, highly educated22 and white5,7 is associated with a greater desire to play an active role in the decision-making process. Our data, on the other hand, might not accurately represent the preferences of more ethnically diverse groups. Indeed, earlier work has shown that ethnic minorities tend to opt for a more passive interaction with their health-care providers.23 Although the reasons for differences in the desire for shared decision making between whites and ethnic minorities are complex, one possible explanation could stem from language barriers. As argued by Frosch and Kaplan37, ‘implementing shared decision making will pose additional challenges when physician and patient do not share a common primary language’ (p. 289). Indeed, a
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large corpus of data has shown that language barriers are associated with both medical disparity.38,39 Our results, thus, do diverge from some earlier studies, showing that patients’ preference for active and collaborative roles depends on the severity and condition of the disease.40,41 A number of factors could help explain this divergence. First, previous studies compared patients and non-patients or patients of different conditions (e.g. diabetes vs. cancer), while we employed a homogeneous population of patients. As such, our study might have the advantage of comparing like to like. Second, we cannot exclude the possibility that our results were affected by the study design, as participants first answered the question about involvement in general and thereafter were asked about their preference in regard to cancer. While we acknowledge this as a possible limitation, it is also important to note that the rate of participants expressing a desire for an active and/or a collaborative role was similar to that reported in earlier work. Our results did reveal an association between numeracy abilities and preference for involvement in the decision-making process. That is, participants who scored high or low on the objective and subjective numeracy scales expressed a different desire for active and collaborative roles in general. Higher objective numeracy scores, but not subjective numeracy scores, were related to women’s desire to have an active role when it came to discussing cancer. It is possible that higher objective (but not subjective) numeracy ability allows at-risk women to interpret and deal with more complicated and emotionally charged medicalrelated information. Furthermore, our novel inclusion of numeracy scales could potentially explain earlier findings showing divergent results with regard to the desire to have an active role. It is possible that earlier work, by focusing on age and education but failing to include numeracy measures, has failed to capture the underlying reasons driving these results. Our data, thus, are not only perfectly aligned with earlier findings,42 but it also
extended earlier work by highlighting the importance of numeracy in women’s preferences in cancer treatment. Our results provide further indications – though with some caveats – for the possibility for using the subjective numeracy scale in the clinical setting. A number of reasons might compel practitioners to use the SNS over other objective scales. Objective measures of numeracy have received negative feedback from users, they tend to suffer from low completion rates, and people, in general, are sensitive about having their objective numeracy abilities evaluated32,33. Utilizing the SNS therefore might allow practitioners the opportunity to employ a more diverse set of measures to evaluate their patients’ numeracy ability. That being said, there is a clear need to further evaluate the specificity, validity and reliability of SNS before extensive adoption of the SNS into clinical practice. Our study extends earlier work in a number of important ways. First, we examined a select group of high-risk patients who had a family history of cancer, rather than the general population. Second, we investigated the desire for decision involvement both in the general medical domain and specifically with regard to cancer treatment. Third, we are the first to examine the link between both objective and subjective numeracy scales and preference for shared decision making. Our data, thus, not only constitute an important contribution to the literature on shared decision making but also provide further support to the growing literature on the importance of numeracy in a wider range of medical areas. What is still missing, however, are studies examining the link between numeracy, decision role and outcome measures (e.g. quality of life, patient satisfaction with decision making). Indeed, while a number of earlier investigations have examined the link between decisional role and quality of life, we know of no study that has also factored in the role numeracy plays within this context. Our findings indicate that health authorities’ recommendations to include patients in their
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medical decisions are supported by patients’ desires. Indeed, very few participants in our study indicated a desire to have a passive role in their medical treatment. The vast majority expressed a clear desire to have a say, whether about their general health or about their cancer treatment. Health-care professionals should be cognizant of their patients’ preferences. While not all patients’ desires are the same, our data suggest that the subjective numeracy scale can help health-care professional in determining their patients’ numerical ability.
Acknowledgements This research was supported by the Cancer Genetics Network, RFA CA-97-004, RFA CA97-019 and RFP No. N01-PC-55049-40 (EO), and a University of Plymouth award (YH).
References 1 Epstein RM, Street RL Jr. Patient-Centered Communication in Cancer Care: Promoting Healing and Reducing Suffering. Bethesda, MD: National Cancer Institute, 2007. 2 Institute of Medicine. Crossing the Quality Chasm: A New Health Care System for the 21st Century. Washington DC: National Academies Press, 2001. 3 Hack TF, Degner L, Watson P, Sinha L. Do patients benefit from participating in medical decision making? Longitudinal follow-up of women with breast cancer. Psychooncology, 2006; 15: 9–19. 4 Tariman JD, Berry DL, Cochrane B, Doorenbos A, Schepp K. Preferred and actual participation roles during health care decision making in persons with cancer: a systematic review. Annals of Oncology, 2010; 21: 1145–1151. 5 Benbassat J, Pilpel D, Tidhar M. Patient preferences for participation in clinical decision making: a review of published surveys. Behavioral Medicine, 1998; 24: 81–88. 6 Auerbach SM. Do patients want control over their own health care? A review of measures, findings, and research issues. Journal of Heath Psychology, 2001; 6: 191–203. 7 Say R, Murtagh M, Thomson R. Patients’ preference for involvement in medical decision making: a narrative review. Patient Education and Counseling, 2006; 60: 102–114.
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8 Chewing B, Bylund CL, Shah B, Arora NK, Guegeun JA, Makoul G. Patient preference for shared decisions: a systematic review. Patient Education and Counseling, 2012; 86: 9–18. 9 Beaver K, Luker KA, Owens RG, Leinster SJ, Degner LF, Sloan JA. Treatment decision making in women newly diagnosed with breast cancer. Cancer Nursing, 1996; 19: 8–19. 10 Singh JA, Sloan JA, Atherton PJ et al. Preferred roles in treatment decision making among patients with cancer: a pooled analysis of studies using the Control Preference Scale. American Journal of Managed Care, 2010; 16: 688–696. 11 Stewart DE, Wong F, Cheung AM et al. Information needs and decisional preferences among women with ovarian cancer. Gynecology & Oncology, 2000; 177: 357–361. 12 Arora NK, McHorney CA. Patient preferences for medical decision making: who really wants to participate? Medical Care, 2000; 38: 335–341. 13 Degner LF, Kristjanson LJ, Bowman D et al. Information needs and decisional preferences in women with breast cancer. JAMA, 1997; 277: 485–1492. 14 Rosen P, Anell A, Hjortsberg C. Patient views on choice and participation in primary health care. Health Policy, 2001; 5: 121–128. 15 Janz NK, Wren PA, Copeland LA, Lowery JC, Goldfarb SL, Wilkins E. Patient-physician concordance: preferences, perception, and factors influencing the breast cancer surgical decision. Journal of Clinical Oncology, 2004; 15: 3091–3098. 16 Strull WM, Lo B, Charles G. Do patients want to participate in medical decision making? JAMA, 1984; 252: 2990–2994. 17 Sutherland HJ, Llewellyn-Thomas HA, Lockwood GA, Tritchler DL, Till JE. Cancer patients: their desire for information and participation in treatment decisions. Journal of the Royal Society of Medicine, 1989; 2: 260–263. 18 Thompson SC, Pitts JS, Schwankovsky L. Preferences for involvement in medical decisionmaking: situational and demographic influences. Patient Education and Counseling, 1993; 2: 133–140. 19 Mansell D, Poses RM, Kazis L, Duefield CA. Clinical factors that influence patients’ desire for participation in decisions about illness. Archive of Internal Medicine, 2000; 160: 2991–2996. 20 Degner LF, Sloan JA. Decision making during serious illness: what role do cancer patients really want to play? Journal of Clinical Epidemiology, 1992; 45: 941–950. 21 Efficace F, Gaidano G, Sprangers M et al. Preference for involvement in treatment decisions and request for prognostic information in newly
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Numeracy Scale. Medical Decision Making, 2007; 27: 672–680. Zikmund-Fisher BJ, Smith DM, Ubel PA, Fagerlin A. Validation of the Subjective Numeracy Scale: effects of low numeracy on comprehension of risk communications and utility elicitations. Medical Decision Making, 2007; 27: 663–671. Galesic M, Garcia-Retamero R. Statistical numeracy for health: a cross-cultural comparison with probabilistic national samples. Archive of Internal Medicine, 2010; 170: 462–468. Rolison JR, Wood S, Hanoch Y, Liu PJ. The subjective numeracy scale as a tool for assessing statistical numeracy in older adult populations. Gerontology, 2013; 59: 283–288. Nease RF, Brooks WB. Patient desire for information and decision making in health care decisions: the autonomy preference index and health opinion survey. Journal of General Internal Medicine, 1995; 10: 593–600. Frosch DL, Kaplan RM. Shared decision making in clinical medicine: past research and future directions. American Journal of Preventive Medicine, 1999; 17: 285–294. Fiscella K, Franks P, Doescher MP, Saver BG. Disparities in health care by race, ethnicity, and language among the insured: findings from a national sample. Medical Care, 2002; 40: 52–59. Flores G, Tomany-Korman SC. The language spoken at home and disparities in medical and dental health, access to care, and use of services in US children. Pediatrics, 2008; 121: e1703–e1714. Butow PN, Maclean M, Dunn SM, Tattersall MH, Boyer MJ. The dynamics of change: cancer patients’ preferences for information, involvement and support. Annals of Oncology, 1997; 8: 857–863. Blanchard CG, Labrecque MS, Ruckdeschel JC, Blanchard EB. Information and decision-making preferences of hospitalized adult cancer patients. Social Science and Medicine, 1988; 27: 1139–1145. Galesic M, Garcia-Retamero R. Do low-numeracy people avoid shared decision making? Health Psychology, 2011; 30: 336–341.
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Shared decision making in patients at risk of cancer: the role of domain and numeracy Yaniv Hanoch PhD,* Talya Miron-Shatz PhD,† Jonathan J. Rolison PhD,‡ Zehra Omer BA§ and Elisa Ozanne PhD¶ *Associate Professor, School of Psychology, Cognition Institute, University of Plymouth, Drake Circus, Plymouth, UK, †Associate Professor, Center for Medical Decision Making, Ono Academic College, Kiryat Ono, Israel, ‡Assistant Professor, School of Psychology, Queen’s University Belfast, Belfast, UK, §Research Associate, Massachusetts General Hospital–Institute for Technology Assessment, Boston, MA, and ¶Associate Professor, The Dartmouth Institute Geisel School of Medicine at Dartmouth, Centerra Parkway, Lebanon, NH, USA
Abstract Correspondence Yaniv Hanoch, PhD University of Plymouth, School of Psychology, Cognition Institute, Drake Circus, PSQ B204, Plymouth, UK, PL4 8AA E-mail: [email protected] Accepted for publication 6 August 2014 Keywords: cancer, objective numeracy and subjective numeracy, shared decision making
Background Shared decision making has become an integral part of medical consultation. Research has, however, reported wide differences in individuals’ desires to be involved in the decision-making process, and these differences in preferences are likely to be the result of a number of factors including age, education and numeracy. Objective To investigate whether patients at genetic risk for cancer had preferences for shared decision making that differed depending on medical domain (general health vs. cancer) and whether decision preferences are linked to numeracy abilities. Methods Four hundred and seventy-six women who consented to participate in response to an email sent by a local branch of the U.S.-based Cancer Genetics Network (CGN) to its members. Participants completed the Control Preference Scale, as well as an objective and subjective numeracy scales. Results Decision domain (cancer vs. general health) was not associated with women’s preferences for involvement in decision making. Objective and subjective numeracy predicted a preference for decision involvement in general, and only objective numeracy was predictive with regard to cancer. Conclusion Participants were equally likely to state they wanted to play an active, collaborative or passive role in both medical domains (general and cancer). High-numeracy participants were more likely to express a desire for an active role in general and in case they were diagnosed with cancer. Practice implications Health authorities’ recommendations to clinicians to include patients in their medical decisions are supported by patients’ desires, and clinicians should be cognizant of their patients’ preferences as well as their numeracy skills.
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Introduction Shared decision making has become an integral part of medical consultation. National health organizations1,2 in the United States, for example, recommend the inclusion of patients in the decision-making process. Indeed, with an increase in health consumerism and the availability of medical information over the Internet, patients have assumed a greater role in managing their health.3 Research4 has, however, reported wide differences in individuals’ desires to be involved in the decision-making process, and these differences in preferences are likely to be the result of a number of factors including age, education and numeracy. While health-care providers have been advised to ensure shared decision making, systematic reviews have highlighted the heterogeneity of patients’ desires regarding this recommendation. One early review5 showed that although a majority of individuals wished to be informed about their illness, the responses were much more varied when individuals were asked about their desire to be actively involved in the treatment decision. In fact, a substantial minority wished to have a passive role, leaving treatment decisions to their doctor. Other reviews6,7 reported similar findings, with an additional investigation8 indicating that 21% of studies show that participants wanted to delegate the decision to their health-care provider. Other studies likewise revealed inconsistencies, with some9–11 reporting a high percentage of participants expressing a desire to have an active or shared role in their treatment decision and others12–14 finding a substantial proportion preferring a passive role in the decision process. Why does the literature present such a mixed picture? Two methodological factors can help explain these divergent results. First, researchers have studied different populations: Some14 have focused on the general public, others15–18 have narrowed their investigations to specific patient populations, and a third group has compared patients with the general population.12,19 In one illustrative study, researchers20 found a schism between the preferences of patients with cancer
and those of the general population regarding involvement in their medical treatment. Although only 12% of the patients with cancer indicated a wish to have an active role in choosing their medical treatment, the rate increased dramatically to 64% among general households. Second, researchers have shown that the nature of the disease affects the level and extent of patients’ desires for involvement. One study14 found that individuals suffering from a chronic disease (e.g. diabetes) were more than twice as likely (31% vs. 12%) as patients with cancer to prefer an active role. Others12 showed that as their medical conditions became graver, individuals preferred to defer treatment decisions to their health-care provider (e.g. for breast patients with cancer).21 There is growing interest in identifying factors that might be associated with the preference for active versus passive (or handing over the decision to the attending physician) shared decision making. Earlier studies largely identified a range of factors – age, education, health literacy, ethnicity and having a regular physician – as important predictors. Early findings20 revealed that age was inversely related to the desire to experience shared decision making, with older participants (both patients with cancer and general household participants) preferring to refer decisions to their physicians. In a large cross-sectional survey with over 3000 participants, researchers22 found that socioeconomic and demographic factors (i.e. ethnicity) and having a regular physician were linked with individuals’ preference for shared decision making. Those with low-income and African American ethnicity were much more likely to favour handing over the decision making to the physicians. An earlier literature review5 identified minority ethnic affiliation, sickness level, age and education as factors that could impede the desire for shared decision making.7,23 While researchers have focused on the above factors, numeracy skills, although shown to be vital in many health-related decision making, have received scant attention. This is surprising, as researchers have long been aware of the important role numeracy plays in different
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medical decisions.24 A large corpus of data revealed an association between low numeracy skills and poorer comprehension of screening information,25 lack of familiarity with the health-care structure,26 and worse health outcomes.27 Of equal importance, it has also been argued that numerical abilities are independent of IQ and education level.28 Indeed, Reyna and colleagues28 stated that ‘on the basis of studies that have controlled for education, intelligence, literacy, and other factors, we can be reasonably sure that numeracy is a separate faculty’ (p. 967). In support of this argument, Wood and colleagues29 found that numeracy predicted performance on a medical insurance decision task independently of other cognitive variables or education, and Brown and colleagues30 showed that numeracy is the key factor in individuals’ ability to interpret graphical breast cancer risk estimates. Based on their own and others’31 findings, it has been argued30 that although the assumption that health literacy and education are related to numerical ability seems intuitively appealing, research repeatedly reveals that education level does not predict numeracy. Historically, numeracy has been measured using objective scales.32 Researchers33 have come to argue that objective numeracy scales (ONS) have a number of shortcomings, such as participants’ dislike of the tests, low completion rates, and that they are difficult to complete over the phone or Internet. Fagerlin and colleagues have developed an alternative measure – known as the subjective numeracy scale (SNS) – as a mean to examine numeric abilities without the above drawbacks. The SNS, in contrast to ONS, only gauge individuals’ perceived ability to deal with mathematical tasks and preference for the use of numerical versus prose information.32,33 Since its publication, a number of studies have validated the SNS among different groups34,35 and have shown that it is faster and easier to administer, offers a more positive experience, has higher completion rates, and can more easily be administered over the phone and Internet.32 In this study, we have included the SNS to examine whether it can help predict
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preference for shared decision making, and serve as a possible alternative for ONS. We had two goals in this study: (i) to determine whether patients at genetic risk for cancer had preferences for shared decision making that differed in two different medical domains: cancer and general health and (ii) to examine the association between both objective numeracy and subjective numeracy abilities and decision preference.
Methods Study participants A total of 1007 women were contacted via an email circulated by a number of local branches of the Cancer Genetics Network (CGN; Table 1) to complete an online survey. Four hundred and seventy-seven women (47% response rate) consented to participate in the study (http://www.cancergen.org/). Only unaffected women at increased risk for breast cancer participated in the study. The inclusion criteria were having at least one relative diagnosed with breast cancer at age 45 or younger, having two or more relatives diagnosed with breast cancer at age 50 or younger, having at least one relative diagnosed with ovarian cancer or having at least one relative diagnosed with male breast cancer. The CGN is a U.S. network of centres that serves as a resource for investigators conducting research on the genetic basis of human cancer susceptibility, integration of this information into medical practice, and behavioural, ethical and public health issues associated with human genetics. A core data set is available on each registrant and contains information on sociodemographic characteristics (although it lacks income information). Participants in this study were recruited and registered on the CGN database by local hospital clinics. They initially provided CGN with baseline data including demographics, family history and disease history. After obtaining consent from all study participants, we extracted an unidentified data set containing
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2802 Shared decision making and numeracy, Y Hanoch et al. Table 1 Demographic (N = 476) Characteristic
Characteristics
of
Participants
their demographic, family and disease history data from the CGN database for analysis.
Value
Duke 40 (8.4%) Emory 25 (5.3%) John Hopkins 74 (15.5%) MD Anderson 25 (5.3%) University of North Carolina 26 (5.5%) University of Utah 129 (27.1%) Colorado 157 (33.0%) Age Mean (SD) 50.5 (7.4) Range 30–61 Education High school or less 29 (6.1%) Some college 105 (22.1%) College graduate 342 (71.8%) Marital status Not married or living together 107 (22.5%) Married or living together 369 (77.5%) Race Asian 3 (0.6%) Black or African American 6 (1.3%) White 454 (95.4%) More than one race 5 (1.1%) Other 5 (1.1%) Unknown or not reported 3 (0.6%) Of Ashkenazi or Eastern European Jewish descent No 418 (87.8%) Yes 46 (9.7%) Unknown 12 (2.5%) Tested for BRCA1/2 gene alterations No 39 (8.2%) Yes 91 (19.1%) Not reported 346 (72.7%) Family member tested for BRCA1/2 gene alterations No 132 (27.7%) Yes 34 (7.1%) Not reported 310 (65.1%) Number of family members with ovarian or breast cancer One 107 (22.5%) Two 97 (20.4%) Three 83 (17.4%) Four 49 (10.3%) Five 26 (5.5%) Six 21 (4.4%) Seven 12 (2.5%) More than seven 11 (2.3%) Not reported 70 (14.7%) Objective numeracy (SD) 1.73 (0.87) Subjective numeracy (SD) 4.70 (0.84) Objective numeracy and subjective numeracy data were missing for three and seventeen participants, respectively.
Study measures The study protocol was approved by the appropriate institutional review boards, and prior to the start of the study, all participants consented to participate in the study. Respondents were informed that the survey would take an estimated 30 min. They were asked to answer a number of questions about shared decision making and objective and subjective numeracy as well as provide demographic information. They were offered the option of receiving a $30 gift card and were not required to answer any question that made them uncomfortable. Shared decision making To study preferences for shared decision making, we utilized one of the most frequently used shared-decision-making measures, the Control Preference Scale.13 The measure asked participants about their (i) desire for involvement in decisions in general, and (ii) their desire for involvement if they were to be diagnosed with breast cancer. The two questions, thus, were designed to probe participants’ preference for shared decision making in general and in regard to cancer. Our measure was adapted from the original study11 where participants were asked to rank the five possible answers; in our case, they were instructed to choose the one answer that best reflected their preference. The precise wording was as follows: Questions: 1. When thinking about the interactions with their doctor, women have different opinions about who should make treatment decisions. Please select one of the following five statements that best reflects your preference for decision involvement in general. 2. When thinking about the interaction with their doctor, women have different opinions about who should make treatment decisions. This might be especially the case with breast
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cancer. Please select one of the following five statements that best reflects your preference for decision involvement if you were to be diagnosed with breast cancer. Responses: A I prefer to make the final selection about which treatment I will receive. B I prefer to make the final selection of my treatment after seriously considering my doctor’s opinion. C I prefer that my doctor and I share responsibility for deciding which treatment is best for me. D I prefer that my doctor make the final decision about which treatment but seriously consider my opinion. E I prefer to leave all decisions regarding treatment to my doctor. Numeracy Objective and subjective numeracy: Respondents completed one of the most extensively used and valid measures of numeracy skill.31 The three-item objective numeracy scale evaluates individuals’ understanding and ability to solve three basic probability and related ratio problems (e.g. ‘Imagine that we flip a fair coin 1000 times. What is your best guess about how many times the coin would come up heads in 1000 flips?’). The measure has been used in hundreds of studies, with a diverse set of population, in wide spectrum of medical decision making, and its psychometrics properties are well established. In addition, an extensive review of the literature28 did not indicate that other, more extensive measures necessarily confer any specific advantage over the more parsimonious31 scale. Each question was scored as correct (coded ‘1’) or incorrect (coded ‘0’). Individual item responses and total number correct were analysed. Following earlier work,34 we have added the scores for each of the three questions and have treated this numeracy score as a continuous variable that ranges from 0 to 3. Participants completed the Subjective Numeracy Scale (SNS),32 a self-report measure of
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perceived ability to perform various mathematical tasks and preference for the use of numerical rather than prose information. The 8-item scale consists of four questions asking respondents to assess their numerical ability in different contexts (e.g. calculating a 15% tip) and four questions asking them to state their preferences for the presentation of numerical and probabilistic information (e.g. preference for percentages vs. words in a weather forecast). Each item is scored on a 6-point Likert scale. The overall SNS score was computed as the average rating across all eight questions. Analysis strategy Logistic regression analyses were conducted on women’s responses to the shared-decisionmaking items. These analyses were performed separately on women’s preferences for decision involvement in general and for decision involvement if they were to be diagnosed with breast cancer. Education and marital status were included as categorical predictors, with age and numeracy included as continuous predictors. Whether women had previously been tested for BRCA1/2 gene alterations and whether a family member had previously been tested for BRCA1/2 gene alterations were included as additional categorical predictors. Objective numeracy was replaced with subjective numeracy ratings in a separate regression model controlling for age, education and marital status. McNemar’s test for repeatedmeasures nominal data was used to test whether women’s preferences for shared decision making in general changed when they imagined that they were diagnosed with breast cancer.
Results Provided in Table 2 are the women’s preferences for decision involvement grouped as ‘active’ (Responses A and B), ‘collaborative’ (Response C) or ‘passive’ (Responses D and E) (see also Fig. 1). Few women (preference in general = 5.9%, preference if diagnosed with
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Shared decision making and numeracy, Y Hanoch et al. Table 2 Women’s Preferences for Decision Involvement in General and if they were to be diagnosed with Breast Cancer (N = 476) Role Characteristic Preference in general Overall (N = 476) Education High school or less (n = 29) Some college (n = 105) College graduate (n = 342) Marital status Not married or living together (n = 107) Married or living together (n = 369) Objective numeracy* (SD) Subjective numeracy (SD) Preference if diagnosed with breast cancer Overall (N = 476) Education High school or less (n = 29) Some college (n = 105) College graduate (n = 342) Marital status Not married or living together (n = 107) Married or living together (n = 369) Objective numeracy (SD) Subjective numeracy (SD)
Active
Collaborative
262 (55.2%)
185 (38.9%)
28 (5.9%)
16 (55.2%) 59 (56.2%) 187 (54.8%)
11 (37.9%) 43 (41.0%) 131 (38.4%)
2 (6.9%) 3 (2.9%) 23 (6.7%)
57 205 1.82 4.77
45 140 1.59 4.59
(53.3%) (55.7%) (0.83) (0.86)
(42.1%) (38.0%) (0.89) (0.78)
Passive
5 23 1.93 4.79
(4.7%) (6.3%) (0.86) (0.94)
258 (54.5%)
175 (37.0%)
40 (8.5%)
15 (51.7%) 60 (58.3%) 183 (53.7%)
14 (48.3%) 39 (37.9%) 122 (35.8%)
0 (0.0%) 4 (3.9%) 36 (10.6%)
59 199 1.80 4.73
40 135 1.60 4.63
(55.7%) (54.2%) (0.84) (0.89)
(37.7%) (36.8%) (0.90) (0.76)
7 33 1.90 4.90
(6.6%) (9.0%) (0.87) (0.73)
Numeracy scores could range between 0 and 3. ‘Preference in general’ data were missing for one participant, ‘preference if diagnosed with breast cancer’ data were missing for three participants, and objective numeracy data were missing for three participants.
*
Preference for decision involvement (%)
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100 90 80
Women's preferences for decision involvement Women’s preference for decision involvement in general Women’s preference for decision involvement if they were to be diagnosed with breast cancer
70 60 50 40 30 20 10 0
Activer role
Collaborative role
Passive role
Figure 1 Women’s preferences for decision involvement in general and if they were to be diagnosed with breast cancer. Error Bars are 95% confidence intervals.
breast cancer = 8.5%) indicated a preference for a passive role. Thus, we focused our logistic regression analyses on whether or not women
had a preference for an active role. As only a minority of women reported that they had previously been tested for BRCA1/2 gene alterations or had a family member who had previously been tested, we included previous testing as additional categorical predictors in our regression analysis in a second block. Higher objective numeracy significantly predicted women’s preference for active decision involvement in general (OR = 1.30; 95% CI: 1.05–1.62; P = 0.017). Effects of objective numeracy are displayed in Fig. 2 (low numeracy = score 0–1, high numeracy = score 2–3). Subjective numeracy ratings were included in a separate regression model as they were highly correlated with women’s objective numeracy scores (r = 0.34, P < 0.001). Subjective numeracy predicted women’s preference for active decision involvement in general (OR = 1.26; 95% CI: 1.01–1.58; P = 0.045). Effects of subjective numeracy are shown in Fig. 2 at low
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100
Low objective numeracy (N = 165)
90
High objective numeracy (N = 307)
80 70 60 50 40 30 20 10 0
Active role
100
Collaborative role
Low subjective numeracy (N = 196)
90
High subjective numeracy (N = 262)
80 70 60 50 40 30 20 10 0
Active role
Collaborative role
100
Passive role
Women's preferences for decision involvement if they were to be diagnosed with breast cancer Low objective numeracy (N = 165)
90
High objective numeracy (N = 307)
80 70 60 50 40 30 20 10 0 Active role
Passive role
Preference for decision involvement (%)
Preference for decision involvement (%)
Preference for decision involvement (%)
Women's preferences for decision involvement in general
school or less, OR = 1.16; 95% CI: 0.73–1.84; P = 0.523), and whether women had previously been tested for BRCA1/2 gene alterations (vs. not previously tested; OR = 0.60; 95% CI: 0.19–1.91; P = 0.385) and whether a family member had previously been tested for BRCA1/2 gene alterations (vs. not previously tested; OR = 1.23; 95% CI: 0.46–3.33; P = 0.684), included in a second block, also did not significantly predict women’s preferences. When women imagined that they had been diagnosed with breast cancer, higher objective numeracy was a significant predictor
Preference for decision involvement (%)
(below the mean rating) and high (above the mean rating) levels. Objective numeracy did not significantly predict women’s preference when included with subjective numeracy in the same regression model (OR = 1.22; 95% CI: 0.97–1.55; P = 0.094), suggesting that subjective ratings capture a large portion of variance in numerical ability. Age (OR = 1.01; 95% CI: 0.98–1.03; P = 0.675), marital status (married or living together vs. not married or living together; OR = 0.92; 95% CI: 0.59–1.42; P = 0.701) and education (some college vs. high school or less, OR = 1.12; 95% CI: 0.51– 2.42; P = 0.783; college graduate vs. high
Collaborative role
Passive role
100 Low subjective numeracy (N = 196)
90
High subjective numeracy (N = 262)
80 70 60 50 40 30 20 10 0
Active role
Collaborative role
Passive role
Figure 2 Women’s preferences for decision involvement in general and if they were to be diagnosed with breast cancer displayed separately for women of high and low levels of objective and subjective numeracy. Error Bars are 95% confidence intervals.
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(OR = 1.26; 95% CI: 1.01–1.56; P = 0.038) of preference for active decision involvement (Fig. 2). Subjective numeracy ratings, included in a separate regression model, did not significantly predict women’s preferences (OR = 1.08; 95% CI: 0.86–1.35; P = 0.510). Age (OR = 1.01; 95% CI: 0.98–1.03; P = 0.524), marital status (married or living together vs. not married or living together; OR = 1.02; 95% CI: 0.66–1.58; P = 0.930) and education (some college vs. high school or less, OR = 1.01; 95% CI: 0.47–2.18; P = 0.980; college graduate vs. high school or less, OR = 1.38; 95% CI: 0.87–2.19; P = 0.177), and whether women had previously been tested for BRCA1/2 gene alterations (vs. not previously tested; OR = 0.82; 95% CI: 0.26–2.59; P = 0.738) or a family member had previously been tested for BRCA1/2 gene alterations (vs. not previously tested; OR = 1.12; 95% CI: 0.42–2.97; P = 0.821) included in a second block, again did not significantly predict women’s preferences. Eighty-four (18%) of the 476 women changed their preferences when asked to imagine they had been diagnosed with breast cancer. For these women, there was no dominant strategy for switching: A fairly even number switched from preferring an active role for general decisions to a collaborative role when they imagined they had breast cancer (32 of 84; 38%) and from preferring a collaborative role for general decisions to an active role when they imagined they had breast cancer (26 of 84; 31%). McNemar’s test confirmed no significant association between switching of preferences from an active to a collaborative role and vice versa (P = 0.511). A minority of the women switched from preferring an active role to a passive role (2 of 84; 2%), or from preferring a collaborative role to a passive role (17 of 84; 20%) when they imaged they had breast cancer, and few women switched from preferring a passive role to a collaborative role (3 of 84; 4%), or from preferring a passive role to an active role (4 of 84; 5%) when they imaged they had breast cancer.
Discussion and conclusion Discussion Current trends encourage the engagement of patients in medical decision making. It is therefore no wonder that researchers and oncologists have been interested in patients’ preferences and decision-making style,30,37,38 as well as in the underlying factors that are linked to patients’ desire for involvement in their treatment decision making. In this study with a large cohort of women at high risk for breast and ovarian cancer, we found, first, that decision domain (cancer vs. general health) did not affect preferences for involvement in decision making. That is, participants were as likely to state they wanted to play an active, collaborative or passive role in their treatment decisions in general as they were in decisions about cancer treatment. This result was unexpected, as earlier studies20 reported that patients with cancer expressed reduced desire to be involved in their medical treatment compared with the general population. Furthermore, others12 have found an inverse relationship between illness severity and a desire for shared decision making. One study21, in fact, found response variation among patients with cancer: those with more severe cancer diagnosis were more likely to defer the decision to their health-care providers. This line of research would suggest a greater desire to be involved in general health decisions compared with cancer-related decisions. Another possibility for our results could rest with the fact that the questions were hypothetical in nature. Indeed, while one systematic review8 has shown that the Control Preference Scale, the instrument used in the current study, is the most frequently used scale, another systematic review4 found that many studies using the Control Preference Scale have revealed a gap between peoples’ preference and their actual involvement. In 19 of the 22 studies included in the systematic review, people expressed greater preference for involvement that actually took place. As such, future
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studies should attempt to measure whether stated preferences are a reasonable predictor of actual behaviour. To our knowledge, ours is the first study to focus on whether women at risk for breast and ovarian cancer express different desires depending on the type of medical (general vs. cancer) condition they face. In other words, in this study, we focused on the domain (cancer vs. general health) within individuals, rather than compare across different populations. Our results indicate that the decision domain made little difference and that the majority of the women would prefer to have either an active or a collaborative role regardless of the magnitude or severity of the decision. That said, 84 of our participants (about 18%) did change their preference depending on the decision domain. Preference changes were, however, inconsistent, as a similar proportion of the women changed from active to collaborative as from collaborative to active. Few women changed their preferences from an active or collaborative role to a passive one. Other factors, not included in our analysis, might also contribute to women’s preference change. It has been shown, for instance, that ethnicity and income are associated with women’s preferences for either a shared or a more passive decision style. It is possible that ethnic minority, less educated and low-income individuals might have exhibited a more pronounce preference reversal. Furthermore, earlier studies36 found that disease severity is associated with decreased desire for being involved in the decision-making process. Given that our sample was at risk but unaffected, we are unable to tell whether disease severity would have altered our results. Finally, it is possible that general health concerns and cancer-specific concerns overlapped to a very large degree, at least in this sample. Our data, furthermore, have important clinical implications. Physicians should be aware that women at risk for breast and ovarian cancer sometimes do change their preferences and that forecasting women’s decision preferences is difficult. Physicians, therefore, who encoun-
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ter this specific population of patients need to ensure that they invest time and effort to verify a woman’s preference on each occasion. Health-care professionals should also be cognizant of their patients’ preferences and refrain from assuming that when dealing with severe illness, patients will not want to be involved in their treatment decisions. Indeed, our data clearly show that women want to take an active role in their treatment decisions. Thus, professionals are encouraged to elicit women’s preferences for involvement in treatment and to actively inquire about the degree to which these preferences generalize across domains. Our sample was composed of well-educated white women at risk for breast and ovarian cancer. In addition, all participants had at least one relative who had been diagnosed with breast or ovarian cancer. As such, the high percentage of participants who expressed a desire to play an active role could represent a ceiling effect. That is, being at high risk for developing breast or ovarian cancer and having relatives who were diagnosed with breast or ovarian cancer could have played a major part in their desire to have an active role. In other words, this group of women had probably given the topic much thought and might have capitalized on their relatives’ experiences with the medical profession. Our results, furthermore, provide support to previous research showing that being female23, highly educated22 and white5,7 is associated with a greater desire to play an active role in the decision-making process. Our data, on the other hand, might not accurately represent the preferences of more ethnically diverse groups. Indeed, earlier work has shown that ethnic minorities tend to opt for a more passive interaction with their health-care providers.23 Although the reasons for differences in the desire for shared decision making between whites and ethnic minorities are complex, one possible explanation could stem from language barriers. As argued by Frosch and Kaplan37, ‘implementing shared decision making will pose additional challenges when physician and patient do not share a common primary language’ (p. 289). Indeed, a
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large corpus of data has shown that language barriers are associated with both medical disparity.38,39 Our results, thus, do diverge from some earlier studies, showing that patients’ preference for active and collaborative roles depends on the severity and condition of the disease.40,41 A number of factors could help explain this divergence. First, previous studies compared patients and non-patients or patients of different conditions (e.g. diabetes vs. cancer), while we employed a homogeneous population of patients. As such, our study might have the advantage of comparing like to like. Second, we cannot exclude the possibility that our results were affected by the study design, as participants first answered the question about involvement in general and thereafter were asked about their preference in regard to cancer. While we acknowledge this as a possible limitation, it is also important to note that the rate of participants expressing a desire for an active and/or a collaborative role was similar to that reported in earlier work. Our results did reveal an association between numeracy abilities and preference for involvement in the decision-making process. That is, participants who scored high or low on the objective and subjective numeracy scales expressed a different desire for active and collaborative roles in general. Higher objective numeracy scores, but not subjective numeracy scores, were related to women’s desire to have an active role when it came to discussing cancer. It is possible that higher objective (but not subjective) numeracy ability allows at-risk women to interpret and deal with more complicated and emotionally charged medicalrelated information. Furthermore, our novel inclusion of numeracy scales could potentially explain earlier findings showing divergent results with regard to the desire to have an active role. It is possible that earlier work, by focusing on age and education but failing to include numeracy measures, has failed to capture the underlying reasons driving these results. Our data, thus, are not only perfectly aligned with earlier findings,42 but it also
extended earlier work by highlighting the importance of numeracy in women’s preferences in cancer treatment. Our results provide further indications – though with some caveats – for the possibility for using the subjective numeracy scale in the clinical setting. A number of reasons might compel practitioners to use the SNS over other objective scales. Objective measures of numeracy have received negative feedback from users, they tend to suffer from low completion rates, and people, in general, are sensitive about having their objective numeracy abilities evaluated32,33. Utilizing the SNS therefore might allow practitioners the opportunity to employ a more diverse set of measures to evaluate their patients’ numeracy ability. That being said, there is a clear need to further evaluate the specificity, validity and reliability of SNS before extensive adoption of the SNS into clinical practice. Our study extends earlier work in a number of important ways. First, we examined a select group of high-risk patients who had a family history of cancer, rather than the general population. Second, we investigated the desire for decision involvement both in the general medical domain and specifically with regard to cancer treatment. Third, we are the first to examine the link between both objective and subjective numeracy scales and preference for shared decision making. Our data, thus, not only constitute an important contribution to the literature on shared decision making but also provide further support to the growing literature on the importance of numeracy in a wider range of medical areas. What is still missing, however, are studies examining the link between numeracy, decision role and outcome measures (e.g. quality of life, patient satisfaction with decision making). Indeed, while a number of earlier investigations have examined the link between decisional role and quality of life, we know of no study that has also factored in the role numeracy plays within this context. Our findings indicate that health authorities’ recommendations to include patients in their
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medical decisions are supported by patients’ desires. Indeed, very few participants in our study indicated a desire to have a passive role in their medical treatment. The vast majority expressed a clear desire to have a say, whether about their general health or about their cancer treatment. Health-care professionals should be cognizant of their patients’ preferences. While not all patients’ desires are the same, our data suggest that the subjective numeracy scale can help health-care professional in determining their patients’ numerical ability.
Acknowledgements This research was supported by the Cancer Genetics Network, RFA CA-97-004, RFA CA97-019 and RFP No. N01-PC-55049-40 (EO), and a University of Plymouth award (YH).
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