Unwanted control: how patients in the primary care setting decide about screening for prostate cancer

Patient Education and Counseling 56 (2005) 116–124

Unwanted control: how patients in the primary care setting decide about screening for prostate cancer Steven H. Woolf a,∗ , Alex H. Krist b , Robert E. Johnson c , Pamela S. Stenborg d a

b

Departments of Family Practice, Preventive Medicine and Community Health, Virginia Commonwealth University, 3712 Charles Stewart Drive, Fairfax, VA 22033, USA Department of Family Practice, Fairfax Family Practice Centers, Virginia Commonwealth University, Fairfax, VA 22033, USA c Departments of Biostatistics and Family Practice, Virginia Commonwealth University, Richmond, VA 23284, USA d Fairfax Family Practice Centers, Fairfax, VA 22033, USA Received 21 August 2003; received in revised form 8 December 2003; accepted 9 December 2003

Abstract Current guidelines recommend shared decision-making to determine whether the prostate-specific antigen (PSA) test should be performed. At a large family medicine practice in suburban Washington, DC, we administered a sequence of patient and physician surveys to examine the desired and actual level of patient control over PSA screening decisions and the circumstances in which they occur. Both before and after visits, patients expressed a preference for a shared approach to the PSA decision, but the actual decision involved a significant shift toward greater patient control. Almost 25% of patients reported greater decisional control than they desired. Fully 30% of the men who wanted a shared approach made the actual decision themselves. Patients prefer a shared approach to the PSA decision but report greater personal control when the decision is actually made. Further research is needed to understand this phenomenon and to better accommodate patients’ desire for shared decision-making. Keywords: Shared decision-making; Participatory decision-making; Patient–physician communication; Prostate cancer; Screening

1. Introduction Continued uncertainties about the benefits and harms of screening for prostate cancer [1] have led most medical organizations to eschew blanket recommendations for or against screening and to instead encourage some form of shared decision-making between the patient and physician before testing is pursued [2–5]. The news media have publicized the consistent message in these guidelines that men should discuss the tradeoffs with their physician and consider personal preferences as a prelude to screening [6,7]. Relatively little is known, however, about primary care physicians’ capacity to offer such counseling, how often it occurs in practice, patients’ desire to share control over decisions, and how choices are ultimately made. Many view locus of control as a continuum, with complete patient and complete physician control over decisions occupying ∗ Corresponding author. Tel.: +1-703-391-2020x141; fax: +1-703-715-8300. E-mail address: [email protected] (S.H. Woolf).

0738-3991/$ – see front matter doi:10.1016/j.pec.2003.12.002

either extreme. How decisions about prostate screening are distributed across that continuum is unclear. A survey in 1996 suggested that physician control was substantial; more than 50% of men tested for prostate-specific antigen (PSA) had not heard of the test and were unaware that they had received it [8]. Familiarity with PSA has increased since 1996. In some cases the locus of control rests firmly with patients, as when men visit the physician to obtain a PSA test, but an unknown proportion of men prefer a middle ground, seeking background knowledge and professional advice from their physician before making a decision. Based on evidence that most patients want information about healthcare choices and that a sizable minority want an active role in making decisions [9,10] considerable work has gone into the development of decision aids to facilitate informed choices [11,12]. Decision aids for prostate screening have been developed, but most evaluative work has focused on whether they affect knowledge or PSA test-ordering practices [13–20]. Few studies have examined the larger questions about the prostate cancer screening decision, such as the degree to which patients want to share control, and

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whether and how such decisions transpire in the clinical encounter. Preliminary data gathered in a randomized trial enabled us to study these issues. In the first phase of the trial, which aims to measure the effect of a pre-visit decision aid on PSA decision-making, we surveyed 161 primary care patients and their physicians to determine the knowledge, attitudes, and process that accompanied their decisions about PSA screening. We contrasted the information the patients provided in telephone interviews prior to their health maintenance examinations with that obtained in exit surveys completed immediately after the visit.

2. Methods 2.1. Setting The study occurred at a large family practice in Fairfax, Virginia, a suburb of Washington, DC. The practice has an average weekly volume of 1000 visits and schedules 24 min for health maintenance examinations. Men over age 50 comprise approximately 9% of the practice’s clientele. Approximately 70% of adult male patients have a college education and 90% have an annual median family income greater than US$ 50,000 [21]. 2.2. Sampling frame The eligible sample was men age 50–70 years who scheduled a health maintenance examination during the months of June 2002 through February 2003. Because the patients were being enrolled in a trial that would test a web-based intervention (see below), eligibility required having Internet access and an email address. In a prior survey, 86% of the practice population reported having Internet access [22]. Patients were excluded if they planned to obtain blood work before the visit (thus preempting an in-office discussion), had a history of prostate cancer, had already been enrolled in the study, or declined participation. 2.3. Pre-visit telephone survey The telephone interviewer placed telephone calls (up to three times if no answer) to eligible patients. She used a scripted text to ascertain whether they met inclusion criteria, to obtain informed consent, and to ask three questions regarding patients’ perspective about PSA screening. The first question, modeled after the Control Preferences Scale (CPS) of Degner and Sloan [23], examined the extent to which the patient preferred to share responsibility for the PSA decision with the physician. The second and third questions examined the patient’s stage of readiness and immediate plans for PSA testing.

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2.4. Educational interventions Enrolled patients were then randomized to one of three groups to test the effectiveness of the decision aid. In a 3:3:1 ratio, patients were assigned, respectively, to a group that was directed to a website with educational material about PSA screening (http://www.acorn.fap.vcu.edu/psa), a group that received a mailed pamphlet with content similar to the website, and a control group that received no pre-visit material. The website and pamphlet discussed prostate cancer, the purpose of and uncertainties surrounding the PSA test, the diagnostic steps and treatments that follow a positive result, and the value of considering personal preferences and seeking input before testing. The content and validation of these decision aids and a comparison of their effects on decision-making will be published elsewhere. 2.5. Exit surveys A patient and physician questionnaire were attached to the front of participants’ charts before the office visit. Most surveys were completed at the conclusion of the visit and deposited in designated collection areas. The patient survey was a 31-item questionnaire that examined demographics, background knowledge [24], the duration and content of the discussion, and whether the PSA test was ordered. The CPS model was used to reassess desired control over decision-making and to characterize how the decision was actually made. O’Connor’s Decisional Conflict Scale [25] was used to measure patient uncertainty about course of action. The physicians’ survey was an 8-item questionnaire that sought their perspective on several domains covered in the patient survey—to contrast patient and physician perceptions—as well as several unique questions asked only of physicians. Copies of both instruments are available from the authors. 2.6. Statistical analysis Data analysis was performed using SAS version 8.2 [26] and StatXact version 4.01 [27]. We determined the statistical significance of differences in patient responses to CPS questions by using an extension to McNemar’s test for marginal homogeneity of ordered responses [28]. This test considers only those men who answer the two questions differently and detects a tendency for changes in response to be in one direction along the continuum. We calculated the mean Decisional Conflict Scores and subscales according to O’Connor [25]. Before completing the telephone interview and the exit survey, patients were advised that their responses would be analyzed in aggregate, would not be linked with personally identifiable information, and would not be shared with their physician. The institutional review board of Virginia Commonwealth University approved the study.

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Table 1 Characteristics of study population Characteristic

Results

Age (median, range)

Number of respondents

57 (50–70)

141

Race Caucasian (N, %) African American (N, %)

127 (90%) 4 (2.8%)

141 141

College education or higher (N, %) Prior testing for prostate-specific antigen (N, %) Looked at website or pamphlet before office visit (N, %)

119 (84%) 102 (72%) 104 (78%)

141 142 133

3. Results

3.2. Plans for and performance of PSA testing

3.1. Study population

When interviewed by telephone before the visit, 44 (27%) respondents indicated they had not yet considered their choices, but 93 (58%) had already decided to obtain a PSA test. PSA testing was ultimately performed on 113 (70%) subjects. As expected, testing was more likely among men who had decided in advance to be tested (Fig. 1). Some men did change their plans; 8% of those planning to be tested before the visit were ultimately not tested. Thirteen percent of physicians reported ordering the PSA to evaluate urologic symptoms or a prior PSA elevation.

During the study period, 329 men age 50–70 scheduled health maintenance examinations. The research assistant was successful in contacting 202 (61%), and 161 (80%) of these men were enrolled. The 41 men who were excluded planned to obtain blood work before the visit (18), lacked an email address (10), had a history of prostate cancer (6), declined participation (5), or were enrolled in a prostate screening study at another institution (2). Of the 161 men who completed the pre-visit telephone interview, 142 (88%) completed exit surveys at the conclusion of the visit. The physicians completed surveys on 140 (87%) of the 161 enrolled patients. Concordant survey pairs—a survey from the physician and the patient he or she examined—were available for 136 (84%) encounters. The demographic profile of the study sample (Table 1) reflected a large proportion of Caucasian, well-educated men. Prior PSA testing was reported by 50% of men age 50–55 and by 85% of older men.

3.3. Patient–physician control over the PSA decision 3.3.1. Orientation to Table 2 Table 2 examines how patients and physicians perceived their control over the screening decision, using the CPS construct to array responses on a continuum that extends from complete patient control to complete physician control. The midpoint of the spectrum, choice C, represents “pure” shared

"When patients schedule a physical examination, they may have an idea whether or not they would like to have a PSA test done. At this time, would you say you..." "Have already made a decision and unlikely to change my mind" (N = 42)

21

2

3

25

"Have already made a decision but still willing to reconsider" (N = 51)

2

PSA ordered

2 11

"Close to selecting an option" (N = 7)

5

PSA not ordered

5

"Considering the options now" (N = 17) "Haven’t begun to think about the choices, but plan on doing so" (N = 19)

5 7

2

1

10

"Haven't begun to think about the choices" (N = 25)

0

5

No physician response

2 4

10

1

15

20

25

30

35

Proportion of respondents (%)

Fig. 1. Testing for prostate-specific antigen (PSA), stratified by patients’ stage of readiness for testing before the visit. In a telephone interview before scheduled health maintenance examinations, patients were asked the question above the figure and chose from the response options listed on the left, which represent the continuum of stages of readiness. Values in the histogram represent the proportion (%) of the 161 respondents who obtained the PSA test, as reported in exit surveys completed by their physicians. In 21 instances the physician did not answer the survey question (“no physician response”). The figure demonstrates the large proportion of patients who come to such visits intending to have the PSA test and their greater likelihood of being tested compared to patients at earlier stages of readiness.

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Table 2 Preferred and actual control over decisions, assessed by patients and physicians according to the Control Preferences Scale Locus of control

Survey responses (N, %) How do you prefer the PSA decision to be made? (1) Patient pre-visit telephone interview (question 1a )

Patient ↑ Pure shared ↓ decision making Physician

A: Patient† B: Patient, doctor’s opinion considered† C: Patient–doctor shared decision† D: Doctor, patient’s opinion considered† E: Doctor† Total

How was the PSA decision made? (2) Patient exit interview (question 1b )

(3) Patient exit interview (question 7c )

(4) Physician exit interview (question 4d )

22 (14) 48 (30)

19 (13) 53 (37)

32 (23) 55 (39)

60 (44) 24 (18)

60 (37) 21 (13) 10 (6)

57 (40) 6 (4) 7 (5)

44 (31) 4 (3) 5 (4)

37 (27) 11 (8) 4 (3)

142 (100)

140 (100)

136 (100)

161

† Based on the Control Preferences Scale [23], in which categories A and B represent a patient-controlled role, category C represents a shared or collaborative role, and categories D and E represent a passive or practitioner-controlled role. a Pre-visit telephone interview question 1 and response options: At this time how do you prefer the decision be made as to whether you have a PSA test? A: I prefer to make the decision about whether to do a PSA test; B: I prefer to make the final decision about whether to do a PSA test after seriously considering my Doctor’s opinion; C: I prefer that my Doctor and I share the responsibility for deciding whether doing a PSA test is best for me; D: I prefer that my Doctor make the final decision about whether to do a PSA test but seriously consider my opinion; E: I prefer to leave all decisions regarding whether to do a PSA test to my Doctor. b Patient exit interview question 1 and response options: In general, for deciding whether to do a PSA test, how do you prefer the medical decision to be made: A: I prefer to make the decision about whether to do a PSA test; B: I prefer to make the final decision about whether to do a PSA test after seriously considering my Doctor’s opinion; C: I prefer that my Doctor and I share the responsibility for deciding whether doing a PSA test is best for me; D: I prefer that my Doctor make the final decision about whether to do a PSA test but seriously consider my opinion; E: I prefer to leave all decisions regarding whether to do a PSA test to my Doctor. c Patient exit interview question 7 and response options: How was the decision made today on whether to do a PSA blood test: A: I made the decision on whether to order a PSA test; B: I made the decision about whether to order a PSA test after seriously considering my Doctor’s opinion; C: My Doctor and I shared the responsibility for deciding whether to order a PSA test; D: My Doctor made the final decision about whether to order a PSA test after seriously considering my opinion; E: My Doctor made the decision whether to order a PSA test. d Physician exit interview question 4 and response options: How was the decision made today on whether to do a PSA blood test: A: The patient made the decision on whether to order a PSA test; B: The patient made the decision about whether to order a PSA test after seriously considering my opinion; C: The patient and I shared the responsibility for deciding whether to order a PSA test; D: I made the decision about whether to order a PSA test after seriously considering the patient’s opinion; E: I made the decision whether to order a PSA test.

decision-making. Responses in columns 1 and 2 addressed how patients preferred the decision be made, whereas responses in columns 3 and 4 described how they felt the decision was actually made. Answers in column 1 were obtained by telephone before the visit. Answers in column 2 were obtained at the exit interview after the visit. During the interval between the pre-visit interview and office visit, 84% of respondents reported having seen the website or pamphlet (see Section 2). Columns 3 and 4 display how the decision was actually made as reported by patients (column 3) and physicians (column 4) on exit surveys. 3.3.2. Patient preferences Columns 1 and 2 demonstrate that “pure” shared decision-making (choice C) was the preferred approach, an option favored by 37% of men before their appointment and by 40% of men after the visit. The second most popular approach, which provided slightly greater patient control (choice B), was preferred by 30% and 37% of men, respectively, before and after the visit. Only 13–14% of patients sought complete control (choice A), and only 9–19% wanted the doctor to decide (choice D or E).

3.3.3. Actual decision Columns 3 and 4 reveal that control over the actual decision departed from patients’ wishes, primarily by giving patients greater control than they had wanted. Whereas 40% of men exited the encounter saying that they would have preferred a purely shared approach (choice C), only 31% indicated that such an approach was used. Fully 23% of patients said that they made the decision themselves (choice A), yet only 13% had wanted to decide in that manner. 3.3.4. Migration The migration pattern between columns A and B (Fig. 2) demonstrates that a number of patients developed a greater interest in pursuing a shared approach at some point between the pre-visit interview and the exit survey. Sixteen (23%) of the 70 men who preferred approaches A or B when interviewed before the visit made a “move to the middle,” indicating at the exit survey that they preferred a purely shared approach (choice C). Conversely, 20 (65%) of the 31 men who wanted the physician to decide (choices D or E) when interviewed before the visit “migrated upward,” indicating a stronger desire for personal control. The shift between

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Fig. 2. “Migration” of desired and actual level of control over the PSA decision. The first column depicts the number of respondents who, in a pre-visit telephone interview, selected choices A through E of the Control Preferences Scale [23] to describe their desired level of control. The second column depicts responses to the same question on an exit survey completed after their appointment. The third column depicts the reported level of control over the actual decision. Arrows between the first and second columns depict migration of patients’ preferences between the pre-visit interview and exit surveys. (During this interval, 84% of patients reported seeing the study’s educational website or pamphlet.) Arrows between the second and third columns depict the migration of patients from desired to actual level of control. For example, of the 21 patients who selected choice D in the pre-visit interview, 7 men (upward arrow) migrated “upward” to choice C on their exit survey, indicating that they preferred a shared approach; 8 of these patients were among the 32 patients who selected choice A to describe how the decision was actually made. Arrow thickness is proportional to the number of patients migrating in that direction, as listed at the base of the arrows. The migration pattern between the first and second columns suggests a shift in preferences toward greater shared and personal control, but the “upward” migration between the second and third columns suggests that patients exerted greater control over the actual decisions than they had wanted. The totals for the three columns differ slightly because some patients did not answer all questions.

columns A and B toward a more patient-oriented decision was statistically significant (P = 0.045). The migration pattern between columns B and C, which contrasts the desired and actual approach, shows a decided “upward” movement across all preference groups, suggesting that patients had more control over the decision than they had wanted. This shift achieved high statistical significance (P < 0.001). Fully 17 (30%) of the 57 men who wanted a purely shared approach (choice C) reported greater personal control over the actual decision (choices A or B). The 32 men who indicated that they made the decision on their own (choice A) included 16 men who had “migrated” from a preferred approach with greater physician input (eight who wanted to decide after considering the doctor’s opinion [choice B] and eight who wanted a purely shared approach [choice C]). Altogether, 32 patients—one out of four

(23%)—reported having greater control over the decision than they had wanted. We found little evidence that physicians took unsolicited control over the decision-making process. Of the 42 men who “migrated” between columns B and C—indicating that the actual decision involved a different degree of control than they had preferred—32 (76%) migrated “upward” (suggesting that the actual decision involved greater patient control) and only 10 (24%) migrated “downward” (greater physician control). 3.3.5. Stratified analysis Examining the above data for differences by group allocation (web, pamphlet, control) is premature because that comparison is the aim of our ongoing randomized trial, and statistically valid conclusions cannot be drawn until the full

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sample (700 subjects) is enrolled. In this preliminary cohort of 161 men, apparent similarities or differences across subgroups must be interpreted cautiously. That said, we found no meaningful differences in the above patterns when responses from each of the subgroups, including controls, were analyzed separately. Men in the control group (not exposed to a pre-visit intervention) also preferred a shared approach (choice C), 36% of those who preferred a shared approach reported greater control over the decision (choice A or B), and 75% of controls who “migrated” between columns B and C reported greater control than they had wanted. The only suggested difference between study arms was in the migration pattern between columns A and B (a shift in preferred decision-making approach between the pre-visit interview and office visit), indicating that the intervention(s) might promote patient interest in a shared approach (choice C). Among men who preferred choices A or B before the visit, 28% and 20% of those assigned to the website or pamphlet, respectively, indicated at the exit survey that they preferred choice C, a preference expressed by only 13% of controls. Among men who at the outset wanted the physician to decide (choice D or E), 89% and 62% of those assigned to the website or pamphlet, respectively, “migrated upward” (sought greater control), whereas the same was true for only 44% of controls. Whether these patterns persist or achieve statistical significance awaits completion of our trial. We also examined whether the observed patterns in desired control varied among men without a prior history of PSA screening. Unfortunately, because only 28% of men (40 subjects) fell in this category, the size of the individual cells was too small for meaningful comparisons of proportions. 3.3.6. Patient–physician concordance Physicians’ perceptions about who controlled the decision were in approximate agreement with those of patients

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(Table 2). Where physicians and patients differed was in assessing the degree to which physicians’ opinions were considered by patients. Physicians thought that only 29% of patients in categories A or B considered their opinions, whereas 63% of such patients thought they had done so. Physicians claimed to have made 11% of the decisions (choices D or E) and to have considered the patient’s opinion (choice D) in 73% of them, whereas the corresponding estimates from patients were 7% and 43%, respectively. Although the estimated proportion of patients who belonged in category C was similar according to patients and physicians (31% and 27%, respectively), in only one-third of cases (13 patients) did they identify the same encounters. Twenty-three of the 37 patients whose physicians reported a purely shared decision (choice C) thought that they had made the decision themselves (choice A or B), and two thought the physician had decided. Conversely, among the 41 patients who did think they exercised choice C, in 22 cases their physicians thought the patient had decided (choice A or B) and in six cases the physicians claimed to have decided (choices D or E). 3.4. Duration and content of discussion Patients estimated that the prostate cancer discussion lasted 0–20 min (median = 5 min). Most (78%) patients estimated that less than 10 min were spent, in most cases (47%) between 5 and 10 min. Physicians thought the discussions were shorter (range of 0–15 min, median = 4 min), with 56% estimating that the discussion lasted less than 5 min. Although 6% of patients said that no topics listed on the survey were discussed, 54% of patients said that 6–10 topics were covered. The topics reportedly discussed most often were the risk for prostate cancer (77%), the meaning of a high PSA (71%), the benefits of testing (70%), and

Table 3 Responses to survey questions assessing knowledge of prostate cancer and PSA screening Question

Correct answer

Proportion marking correct answer (%)

Proportion answering, “I don’t know” (%)

“Prostate cancer is one of the most common cancers among men” “The PSA test will pick up ALL prostate cancers” “How many men with a high PSA level will have prostate cancer?”

A. True B. False C. Most will not have prostate cancer A. True

94 85 28a

6 12 30

86

11

A. True

85

7

C. Most of them will not die from it A. True

61b

27

84

11

A. True

85

11

“If you have an abnormal PSA test result, your doctor may recommend that you have a prostate biopsy” “Early detection of prostate cancer by PSA testing has the potential to extend the life of men with prostate cancer but this has not been proven” “How many untreated men with early stage prostate cancer will actually die BECAUSE of the prostate cancer?” “Loss of sexual function is a common side effect of prostate cancer treatments” “Problems with urination are common side effects of prostate cancer treatments”

Questions adapted from O’Dell et al. [24]. Proportions based on 142 respondents. a “Most or all will have prostate cancer” (10%). “About half will have prostate cancer” (32%). b “Most or all will die from it” (4%). “About half will die from it” (8%).

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testing options (70%). The four lead topics that physicians recalled covering were the benefits (73%) and risks (71%) of testing, testing options (65%), and the risk for prostate cancer (61%). 3.5. Patient knowledge Three-quarters (75%) of physicians reported that patients exhibited “good understanding of the risks and benefits of PSA testing.” Although patients’ responses to eight questions demonstrated relatively good knowledge levels, a sizable minority expressed uncertainty regarding subtopics (Table 3). 3.6. Decisional conflict The mean Decisional Conflict Score was 1.5 and the mean subscale scores ranged from 1.4 to 1.7. (A score below 2 is associated with acceptance of an intervention [25].)

4. Discussion Our study offers insight into the attitudes and process that primary care patients bring to the PSA screening decision. In this cohort of patients we found that 58% came to the health maintenance examination planning to be tested, and testing ultimately occurred in 70% of visits. The PSA test is no longer unfamiliar to primary care patients: 72% of these men had been tested before. These results are consistent with other studies in the United States, which indicate that 75% of men age 50 and older have had a PSA test, that 65% expect to get the test at annual physical examinations, and that a PSA test is ordered at 80% of such visits [29–31]. The need remains, however, for providing men with better information. One-quarter of this cohort had not considered whether to get a PSA before their visit. A sizable minority was unsure of the basic facts about prostate cancer. Physicians spent an average of 4–5 min, sometimes up to 20 min, discussing these issues, usually covering 6–10 topics. In future articles we will explore these findings, as well as the primary outcomes of our randomized trial. The finding that captures our attention here, however, relates to patient and physician perspectives about shared decision-making. Although medical organizations agree that prostate cancer screening should involve shared decision-making [2–5], it is often said that patients do not desire this approach and would rather have the doctor decide. Our results suggest otherwise. This cohort of patients preferred a truly shared decision, and relatively few wanted the decision made by the physician. Others have reported similar results. Frosch et al. [18] found that a shared approach to the prostate cancer screening decision was preferred by 47% of those who received usual care and by 55–70% of those who received preliminary information. Davison et al. [16], using the CPS construct in

a group of 100 men considering prostate cancer screening, found that preferences for choices A, B, C, D, and E, respectively, were expressed by 6%, 33%, 35%, 12%, and 14% of patients, half of whom were randomized to an educational intervention. We had expected our “migration” analysis (Fig. 2) to reveal that physicians exert greater control over decisions than patients desire, but our results suggest the opposite. We observed a statistically significant shift toward greater patient control over the PSA decision, with a sizable proportion of patients reporting greater control than they said they wanted. Half the men who made the decision on their own reported that they would have preferred a truly shared approach (choice C). The phenomenon did not appear to vary based on exposure to a pre-visit decision aid. This “unwanted control” has many potential explanations. First, the study may have altered the decision-making process. The physicians, unblinded to enrollment (exit surveys were clipped to the charts), may have altered their normal discussion style in the expectation that our study aimed to promote patient control. Physicians who normally handle the PSA topic in a more paternalistic or controlling fashion might have made an exception with study patients and passively or actively encouraged greater patient control. Alternatively, patients may have inferred from the survey or comments made by the physician that the “right answer” was to say that they made the decision themselves. Their use of the CPS construct may have differed subtly between characterizing a preferred style for decision-making and describing a completed discussion. One could speculate that patients took greater control over the decision due to exposure to our decision aids, which occurred in 84% of respondents. The knowledge or encouragement that they gained might have diminished interest in soliciting physician input. This possibility is supported by two studies of prostate screening decision-making, which showed that exposure to information increased patient engagement [16,18]. Davison et al. [16], using a similar CPS construct, reported that patients preferred choice C but that those randomized to an educational intervention were more likely than controls (31% versus 11%) to select A or B in characterizing the actual decision. Trials of decision aids on other topics have also reported increased patient control [32–36]. These findings are generally interpreted as evidence that decision aids are beneficial. However, the few studies that asked patients how they wanted to make decisions [32,33,36] reported, as we did, that those who preferred a shared role often made the decision on their own. The inference that a more controlling role is a positive outcome—where positive is defined as a level of control consistent with patients’ wishes—assumes that educational interventions shift patients’ preferences away from a shared approach and toward greater personal control. Previous studies could not challenge this assumption because their data on preferred decision-making styles were collected before, and not after, patients saw the aids. Our study, which did

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both, found that preferences for active involvement did increase after exposure, but not to a degree to account for the more significant shift toward patient control in the actual decision. It was in the same exit survey that respondents reported greater patient control and expressed a preference for a shared approach. From this we infer that many patients exercised greater control over decisions than they wanted. Patient control is affected by physician behavior [37], and one potential explanation for exercising greater control than wanted is that patients may find physicians unprepared to conduct a shared decision. By default patients may assume control. Alternatively, patients, more so than physicians, may be unprepared for a shared decision. Although patients may express a preference in the abstract for shared decisions, in practice they may be uncomfortable with that approach. Various psychological factors could make a shared decision cognitively or emotionally threatening, and patients may find it easier to expedite the decision. The decision may be too complex to occur in a shared fashion without tools designed to facilitate mutual involvement in decision-making. Farrell et al. [38] found that underlying beliefs eclipsed counseling information in influencing PSA decisions. These limitations would suggest the need for devoting greater attention to understanding the psychological and operational barriers that clinicians, health systems, and patients face in accepting and implementing shared decision-making. Finally, we do not presuppose that unwanted control is inherently an adverse outcome. Given the inability of physicians (or anyone else) to fully appreciate another’s personal preferences, it may be that patients must ultimately take control to ensure that choices conform to their values. We note that, despite the shift in control, patients in our study reported low decisional conflict in their decisions. Street et al. observed that patients who prefer shared control tend to participate more actively [39]. Moreover, even if a better PSA decision would occur under a shared model, it may be in the patient’s interest to redirect the limited time and cognitive energy available for complex choices toward other health issues of greater importance. Several aspects of our study limit its generalizability. First, the socioeconomic status of our respondents may not represent typical primary care patients. Less affluent patients and those from other geographic settings might feel less empowered and prefer greater physician control. Men who had never been screened before were poorly represented in our sample. Second, we surveyed only half the men in the sampling frame, creating a potential selection bias. Third, the CPS construct, although validated in varied settings [16,23,40,41] may mischaracterize patient preferences. Its robustness, supported by the correlation between patients’ and physicians’ ratings that we and others [16] have observed, is tempered by the discordance we observed in individual cases and by published criticisms in other reports [42]. Fourth, the wording of our questions or the sequence with which they appeared may have confounded our results. Cues introduced by preceding questions may have

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skewed responses. Finally, results may differ as we accrue a larger sample size. Further research is needed to replicate our findings, including the apparent phenomenon of “unwanted control,” in other primary care settings.

Acknowledgements The authors thank Annette O’Connor, Robert J. Volk, and Andew M. Wolf for their advice on the study, and B. Joyce Davison, Vikki Entwistle, and an anonymous reviewer for their useful suggestions on the manuscript. We also thank the Virginia Ambulatory Care Outcomes Research Network (ACORN) for providing infrastructure support for the study. Financial support from Joint American Academy of Family Physicians Foundation-American Academy of Family Physicians Grant No. G0113 is acknowledged.

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