Perceptions of breast cancer risk and screening effectiveness in women younger than 50 years of age.

BACKGROUND: The National Cancer Institute has recently changed its approach and has substituted summary-of-evidence statements for specific recommendations for breast cancer screening in women 40-50 years of age, leaving these women with a greater share of decision-making responsibility. To make an informed decision about breast cancer screening, women need accurate information about their breast cancer risk and the benefit of screening. Although it has been suggested that women younger than 50 years of age overestimate this risk and benefit, their estimates have not been quantified. PURPOSE: The purpose of this study was to determine how women 40-50 years of age perceive their risk of breast cancer and the effectiveness of screening and how these perceptions compare with estimates derived from epidemiologic studies of breast cancer incidence and randomized clinical trials of screening. METHODS: We mailed a questionnaire to 200 women, identified through the computerized medical records of Dartmouth-Hitchock Medical Center, who were between 40 and 50 years of age and had no history of breast cancer. Each woman was asked about her risk factors for breast cancer and asked to estimate her probabilities of developing breast cancer and dying of it within 10 years, with and without screening. The women's answers were compared with individual probabilities derived from the Gail et al. model, age-specific probabilities of developing and dying of breast cancer in the United States, and the results of randomized clinical trials of screening. RESULTS: The mailed questionnaire was completed and returned by 145 (73%) of the 200 women. Respondents over-estimated their probability of dying of breast cancer within 10 years by more than 20-fold (median, 22.3; interquartile range, 11.1-74.2). Assuming a 10% relative risk reduction from screening, respondents overestimated the relative risk reduction by sixfold (median, 6.0; interquartile range, 5.0-7.5) and the absolute risk reduction more than 100-fold (median, 127.5; interquartile range, 47.1-399.6). The median perceived estimate of absolute risk reduction was 6.0 breast cancer deaths per 100 women; the median calculated estimate was only 0.04 per 100 women. CONCLUSION: These findings suggest that many women younger than 50 years of age substantially overestimate their breast cancer risk and the effectiveness of screening. IMPLICATIONS: A balanced presentation of information about breast cancer risk and screening effectiveness may improve decision making for women younger than 50 years of age and reduce their anxiety about breast cancer, regardless of whether they choose to be screened.

Patient preferences for adjuvant interferon alfa-2b treatment.

PURPOSE: Although trials of adjuvant interferon alfa-2b (IFN alpha-2b) in high-risk melanoma patients suggest improvement in disease-free survival, it is unclear whether treatment offers improvement in overall survival. Widespread use of adjuvant IFN alpha-2b has been tempered by its significant toxicity. To quantify the trade-offs between IFN alpha-2b toxicity and survival, we assessed patient utilities for health states associated with IFN therapy. Utilities are measures of preference for a particular health state on a scale of 0 (death) to 1 (perfect health). PATIENTS AND METHODS: We assessed utilities for health states associated with adjuvant IFN among 107 low-risk melanoma patients using the standard gamble technique. Health states described four IFN alpha-2b toxicity scenarios and the following three posttreatment outcomes: disease-free health and melanoma recurrence (with or without IFN alpha-2b) leading to cancer death. We also asked patients the improvement in 5-year disease-free survival they would require to tolerate IFN. RESULTS: Utilities for melanoma recurrence with or without IFN alpha-2b were significantly lower than utilities for all IFN alpha-2b toxicities but were not significantly different from each other. At least half of the patients were willing to tolerate mild-moderate and severe IFN alpha-2b toxicity for 4% and 10% improvements, respectively, in 5-year disease-free survival. CONCLUSION: On average, patients rate quality of life with melanoma recurrence much lower than even severe IFN alpha-2b toxicity. These results suggest that recurrence-free survival is highly valued by patients. The utilities measured in our study can be applied directly to quality-of-life determinations in clinical trials of adjuvant IFN alpha-2b to measure the net benefit of therapy.

Cost-effectiveness analysis in clinical practice: the case of heart failure.

Heart failure is the leading cause of hospitalization in adults older than 65 years, and it is currently the most costly cardiovascular disorder in the United States, with estimated annual expenditures in excess of $20 billion. Recent studies have shown that selected pharmacological agents, behavioral interventions, and surgical therapies are associated with improved clinical outcomes in patients with heart failure, but the cost implications of these diverse treatment modalities are not widely appreciated. In this review, a brief outline of cost-effectiveness analysis is provided, and current data on the cost-effectiveness of specific approaches to managing heart failure are discussed. Available evidence indicates that angiotensin converting enzyme inhibitors, other vasodilators, digoxin, carvedilol, multidisciplinary heart failure management teams, and heart transplantation are all cost-effective approaches to treating heart failure; moreover, some of these interventions may result in net cost savings.

Cost-effectiveness of HIV screening in acute care settings.

BACKGROUND: Although screening inpatients for human immunodeficiency virus (HIV) in acute care hospital settings has been recommended, the cost-effectiveness of screening is not known. OBJECTIVE: To estimate the cost-effectiveness of a voluntary screening program in acute care hospitals and associated clinics. RESULTS: During the first year, an HIV screening program implemented in acute care hospital settings in which the seroprevalence of HIV infection is 1% or more would result in the identification of approximately 110,000 undetected cases of HIV infection. The program would result in expenditures of approximately $171 million for testing and counseling, and expenditures of approximately $2 billion for incremental medical care for the patients identified as having HIV infection during the first year of screening. When the seroprevalence of HIV is 1%, the cost-effectiveness of screening is $47,200 per year of life saved. When the effect of early identification of HIV infection on the patient's quality of life also is considered, screening is less cost-effective. Screening-induced reductions in risk behavior improve the cost-effectiveness of screening by preventing the transmission of HIV.

Occupational exposure to human immunodeficiency virus and hepatitis B virus: a comparative analysis of risk.

OBJECTIVE: To estimate the occupational risk from infection with the human immunodeficiency virus (HIV) in terms of loss of (quality-adjusted) life expectancy, and to compare that risk to those posed by other hazards faced by health care workers. DESIGN: Decision-analytic model. RESULTS: For a 30-year-old female health care worker (unvaccinated for hepatitis B virus [HBV]), the loss of life expectancy from a needlestick from a symptomatic HIV-positive (HIV+) patient is 39 days (range, 17 to 93 days), as compared with a loss of 17 days from a needlestick from a patient who is hepatitis-B-surface-antigen-positive (HBsAg+), and 38 days from a needlestick from a patient who is hepatitis-B-e-antigen-positive (HBeAg+). When morbidity is included in the analysis of risk (through calculation of the quality-adjusted loss of life expectancy), the risk from both HBV and HIV increases. The quality-adjusted loss of life expectancy due to a needlestick exposure from a symptomatic HIV+ patient is 45 days (range, 20 to 108 days), as compared with a quality-adjusted loss of life expectancy of 48 days from a needlestick from an HBsAg+ patient, and 109 days from a needlestick from a patient who is known to be HBeAg+. By comparison, a cross-country automobile trip is associated with a loss of life expectancy of approximately 1 day. The 45- to 50-day loss of quality-adjusted life expectancy from percutaneous exposures to HIV and HBV is approximately the same magnitude as the gain in life expectancy from 10 years of annual screening for breast cancer with mammography and physical examination. CONCLUSIONS: The risk associated with percutaneous exposures to symptomatic HIV+ patients is comparable to other risks that health care workers have faced knowingly and have accepted in the recent past. However, the loss of quality-adjusted life expectancy associated with a needlestick exposure is significant. Identification of cost-effective methods that increase the safety of medical personnel but also ensure full access to high-quality care for HIV+ patients should be a high priority.

The decision to enter a randomized trial of tamoxifen for the prevention of breast cancer in healthy women: an analysis of the tradeoffs.

OBJECTIVE: Interest in breast cancer prevention has led to the Breast Cancer Prevention Trial (BCPT), a controversial randomized trial of tamoxifen for women at risk for breast cancer. The goal of our study was to determine whether the potential benefits of enrolling in the randomized trial of prophylactic tamoxifen outweigh the potential risks. METHODS: We used a decision analytic model based on the available data on tamoxifen treatment benefits in women with breast cancer and extrapolated to its use in healthy women. RESULTS: For a 50-year-old woman with a breast cancer risk twice that of the average woman her age, the BCPT offers an increase in life expectancy of about 9 days, a gain that is modest compared with other health interventions. For women ages 35 to 60 who meet the minimum risk of breast cancer for trial eligibility, the trial increases life expectancy by about 8 or 9 days. Assumptions about the effect of tamoxifen on the incidence of endometrial and liver cancer and on quality of life associated with tamoxifen did not alter our findings. CONCLUSIONS: Advocates and opponents of the BCPT should temper their concerns to reflect the modest absolute benefits and harms associated with the trial. Although women at increased risk for breast cancer should be aware of the likely overall benefit associated with entry into the trial, for most women, entry into the BCPT is unlikely to alter substantially their length of life, in either a beneficial or harmful manner.

Use of the polymerase chain reaction in the diagnosis of herpes simplex encephalitis: a decision analysis model.

PURPOSE: To evaluate the utility of an assay based on a polymerase chain reaction (PCR) of cerebrospinal fluid in the management of patients with suspected herpes simplex encephalitis. METHODS: A decision model was constructed and used to compare a PCR-based approach with empiric therapy. Inputs required by the model included the sensitivity (96%) and specificity (99%) of PCR (derived from review of the literature), the prevalence of herpes simplex encephalitis (5%, based on the actual prevalence at Barnes Hospital among patients treated empirically with acyclovir), the outcomes for patients with and without herpes simplex encephalitis (derived from clinical studies of the Collaborative Antiviral Study Group and the actual experience at Barnes Hospital), and the average duration of empiric acyclovir therapy for patients with possible herpes simplex encephalitis (5.3 days based on actual experience at Barnes Hospital). RESULTS: Using these input values, the decision model predicted better outcomes with empiric therapy. However, low rates of inappropriate discontinuation of empiric therapy in patients with herpes simplex encephalitis or improved diagnosis and outcome resulting from a negative PCR assay result in patients without herpes simplex encephalitis led to better outcomes with the PCR-based approach. The PCR-based approach was associated with 9.2 fewer doses of acyclovir per patient. CONCLUSION: Based on the decision model using conservative assumptions, a PCR-based approach can yield better outcomes and reduced acyclovir use compared with empiric therapy.

Parents' preferences for outcomes associated with childhood vaccinations.

BACKGROUND: The number of shots in the childhood immunization schedule has been increasing and is likely to continue to increase in the coming years. Consideration of the psychologic costs of multiple injections, adverse events and vaccine-preventable disease is therefore growing in importance. METHODS: We assessed parent preferences, using both the time tradeoff (i.e. amount of parent time willing to trade) and willingness-to-pay (i.e. dollars willing to pay) metrics, for possible outcomes of vaccination among 206 parents of infants receiving care at Kaiser, Northern California Region. We also explored the relationship between preferences and subject characteristics. RESULTS: In general the amount of time subjects were willing to give up and the quantity of money they were willing to spend to avoid an outcome increased with the severity of the outcome. Preferences for our six main outcomes of interest all differed from one another (P < 0.0001, Tukey's multiple comparisons procedure). Rank correlation coefficients between time tradeoff and willingness-to-pay values for the six main outcomes ranged from 0.42 to 0.52 (all P < 0.004). Subject characteristics, including education, income, race/ethnicity and the child's birth order, did not explain the variation in parent preferences. CONCLUSIONS: In general subjects were willing to give up more money or time to avoid less desired outcomes. They were willing to give up only very small amounts of their own life expectancy or money to avoid minor, temporary outcomes (e.g. moderate fussiness, fever and pain) whereas they were willing to forego substantial lengths of their life or amounts of money to avoid a major, permanent outcome (i.e. permanent disability). Nonetheless much variation surfaced in the amount of time (or money) subjects were willing to trade to avoid outcomes. If this variation represents true differences in preferences, guideline developers must consider the role of individual parent preferences in decisions concerning vaccination.

Procedure-related miscarriages and Down syndrome-affected births: implications for prenatal testing based on women's preferences.

OBJECTIVE: To determine how pregnant women of varying ages, races, ethnicities, and socioeconomic backgrounds value procedure-related miscarriage and Down-syndrome-affected birth. METHODS: We studied cross-sectionally 534 sociodemographically diverse pregnant women who sought care at obstetric clinics and practices throughout the San Francisco Bay area. Preferences for procedure-related miscarriage and the birth of an infant affected by Down syndrome were assessed using the time trade-off and standard gamble metrics. Because current guidelines assume that procedure-related miscarriage and Down syndrome-affected birth are valued equally, we calculated the difference in preference scores for those two outcomes. We also collected detailed information on demographics, attitudes, and beliefs. RESULTS: On average, procedure-related miscarriage was preferable to Down syndrome-affected birth, as evidenced by positive differences in preference scores for them (time trade-off difference: mean = 0.09, median = 0.06; standard gamble difference: mean = 0.11, median = 0.02; P <.001 for both, one-sample sign test). There was substantial subject-to-subject variation in preferences that correlated strongly with attitudes about miscarriage, Down syndrome, and diagnostic testing. CONCLUSION: Pregnant women tend to find the prospect of a Down syndrome-affected birth more burdensome than a procedure-related miscarriage, calling into question the equal risk threshold for prenatal diagnosis. Individual preferences for those outcomes varied profoundly. Current guidelines do not appropriately consider individual preferences in lower-risk women, and the process for developing prenatal testing guidelines should be reconsidered to better reflect individual values.

Cost-effectiveness of preoperative autologous donation in coronary artery bypass grafting.

Concern about the safety of the allogeneic blood supply has made preoperative autologous blood donation (PAD) routine before major noncardiac operations. However, the costs and benefits of PAD in elective coronary artery bypass grafting (CABG) are not well established. We used decision analysis to (1) calculate the cost-effectiveness of PAD in CABG, expressed as cost per year of life saved, and (2) compare the health benefits of reducing allogeneic transfusions with the potential risks of autologous blood donation by patients with coronary artery disease. A prospective study of 18 institutions provided data on transfusion practice and blood product costs in CABG. On average, PAD in CABG costs $508,000 to $909,000 per quality-adjusted year of life saved, depending on the number of units donated. Preoperative autologous blood donation is more cost-effective (as low as $518,000 per year of life saved) when targeted to younger patients undergoing CABG at centers with high transfusion rates. The cost-effectiveness of PAD is strongly dependent on estimates of posttransfusion hepatitis incidence, but less so on plausible estimates of the current risk of human immunodeficiency virus transmission. Although the actual risk of PAD is uncertain, even a small fatality risk (> 1 per 101,000 donations) associated with blood donation by patients awaiting CABG negates all life expectancy benefits of PAD. At current costs, PAD by patients awaiting CABG is not cost-effective, producing small health benefits at high societal cost. For the individual patient, the risk of donating blood before CABG may well outweigh the benefits associated with fewer allogeneic transfusions.

Finding equilibrium in U.S. physician supply.

One essential component of health system reform is to bring the number of physicians in line with the needs of the population. The physician supply policies of prepaid group practice health maintenance organizations have been cited as one model to achieve this goal. Planning for physician supply should be an explicit public-sector activity and should not be left to the private sector, because some areas are not sufficiently populated to support competing providers under a managed competition scheme. A new model for planning for physician supply should include the following strategies: (1) erecting barriers to entry into medical practice; (2) encouraging early retirement; (3) restructuring economic incentives; (4) reallocating physicians to underserved areas in the United States and abroad; and (5) creating new areas of professional responsibility for physicians.

Assessing the preferences of patients with psoriasis. A quantitative, utility approach.

BACKGROUND AND DESIGN: Patient preferences for health outcomes can be explicitly assessed and expressed in quantitative terms known as utilities. Three standard methods for utility assessment have been used to quantify patient preferences, but these methods have not previously been applied to skin disease. Eighty-seven patients with psoriasis from a tertiary medical center were interviewed, using an interactive, computer-based utility assessment questionnaire, U-Titer. Utilities for three categories of psoriasis severity and potential adverse outcomes of methotrexate therapy were assessed by the vertical rating scale, time trade-off, and standard gamble. RESULTS: Patients assigned a broad range of utilities for each of the health states. Utilities obtained by the vertical rating scale did not correlate well with utilities obtained by standard gamble or time trade-off methods. However, utilities assessed by standard gamble and time trade-off were not significantly different. Patient characteristics such as age, gender, and education were not correlated with utility and did not explain the variation. Indicators of the patients' disease severity were not predictive of utilities for the assessed health states. The relatively high utility for liver biopsy suggests that there is less patient aversion to the procedure than suspected. CONCLUSIONS: Utilities, or quantitative measures of patient preferences for health states, are measurable and vary widely for mild, moderate, and severe psoriasis and possible adverse outcomes of methotrexate treatment. The process of elucidating individual patient utilities for various health outcomes can be used to incorporate patient preferences into the process of clinical decision making. Guidelines that are based solely on severity of symptoms, without input from patients on how they value such symptoms, must be questioned.

The importance of patient preferences for comorbidities in cost-effectiveness analyses.

When using cost-effectiveness analyses to prioritize the allocation of health care resources across patients, a standard definition of effectiveness must be used. In an informal review of cost-effectiveness analyses, we found a heterogeneity in the methods used to qualify adjust years of life. Many studies do not account for the morbid conditions that patients experience other than the index condition being studied. These studies systematically overstate health benefit relative to studies that do for comorbidities. We recommend that patient preferences for comorbid conditions be incorporated into analyses to allow a consistent and facile comparison of cost-utility ratios for societal decision making.

Utility-based estimates of the relative morbidity of visual impairment and angina.

PURPOSE: To quantify and compare the reduction in quality of life due to visual impairment and angina using patient preferences (utilities). METHODS: Using a standard time tradeoff method, we obtained utilities for current vision, monocular and binocular blindness, current angina, and moderate angina in 60 patients with both vision problems and angina pectoris who sought care at the National Eye Institute (NEI), National Naval Medical Center, or Barnes-Jewish Hospital. Patients were characterized clinically based on visual acuity and the Duke Activity Status Index (DASI). Patients also completed a seven-item version of the NEI Visual Functioning Questionnaire and the SF-36 Health Survey Questionnaire. RESULTS: Patients had a median visual acuity of 20/100 in the worst eye, 20/40 in the better eye, and a median DASI of 24.2 (0 = severe functional limitations due to anginal symptoms, 58.2 = no limitations). There was substantial variation in utilities among patients. The average utility for current vision (relative to ideal vision [= 1.0] and death [= 0.0]) was 0.82; the average utility for current angina (relative to no angina symptoms [= 1.0] and death [ = 0.0]) was 0.89. Among 26 patients with both visual impairment and recent anginal symptoms, the decrement in utility (on a scale ranging from ideal health [= 1.0] to death [= 0.0]) imposed by current visual impairment was greater than that imposed by current angina symptoms (0.146 versus 0.072, p=0.08, Wilcoxon signed rank test). The decrement in utility associated with binocular blindness was greater than the decrement associated with the symptoms of moderate angina (0.477 versus 0.039, p<0.0001). CONCLUSIONS: Clinical status is not a surrogate for patient preferences regarding vision impairment or angina. There is substantial variation in utilities within the study population for both experienced and theoretical impairment states which is not explained by variations in clinical status. Some states of visual impairment may pose a greater quality of life burden than anginal symptoms. Because patient preferences for vision vary greatly, individual assessment is warranted for consideration in therapeutic decision making.

Do violations of the axioms of expected utility theory threaten decision analysis?

Research demonstrates that people violate the independence principle of expected utility theory, raising the question of whether expected utility theory is normative for medical decision making. The author provides three arguments that violations of the independence principle are less problematic than they might first appear. First, the independence principle follows from other more fundamental axioms whose appeal may be more readily apparent than that of the independence principle. Second, the axioms need not be descriptive to be normative, and they need not be attractive to all decision makers for expected utility theory to be useful for some. Finally, by providing a metaphor of decision analysis as a conversation between the actual decision maker and a model decision maker, the author argues that expected utility theory need not be purely normative for decision analysis to be useful. In short, violations of the independence principle do not necessarily represent direct violations of the axioms of expected utility theory; behavioral violations of the axioms of expected utility theory do not necessarily imply that decision analysis is not normative; and full normativeness is not necessary for decision analysis to generate valuable insights.

A method for estimating the cost-effectiveness of incorporating patient preferences into practice guidelines.

Many clinical practice guidelines fail to account for the preferences of the individual patient. Approaches that seek to include the preferences of the individual patient in the decision-making process (e.g., interactive videodisks for patient education), however, may incur substantial incremental costs. Developers of clinical practice guidelines must therefore determine whether it is appropriate to make their guidelines flexible with regard to patient preferences. The authors present a formal method for determining the cost-effectiveness of incorporating the preferences of individual patients into clinical practice guidelines. Based on utilities assessed from 37 patients, they apply the method in the setting of mild hypertension. In this example, they estimate that the cost-effectiveness ratio for individualized utility assessment is $48,565 per quality-adjusted year of life, a ratio that compares favorably with other health interventions that are promoted actively. This approach, which can be applied to any clinical domain, offers a formal method for determining whether the incorporation of individual patient preferences is important clinically and is justified economically.

Solid recommendations from soft numbers: the test/treatment decision.

The authors review the probability threshold approach to test/treatment decisions developed by Pauker and Kassirer, emphasizing that certain aspects of the nature of medical decisions call for a new approach. The utility threshold approach, while maintaining all the advantages of threshold methods in general, brings improvements. It diminishes the need to accurately assess one of the decision's parameters: the patient's utility for the outcome states. For a simple case of one disease with three outcome states (cured, diseased, dead) and one test, three utility thresholds are derived. The treat/no treat threshold, denoted by u, separates the utility space in two. If the patient's value for the diseased state is greater than u, the analyst can feel confident in recommending the patient forego treatment. Similar interpretations are developed for u1, the no treatment/test utility threshold (the value u must take, given a positive test result, for the patient to be indifferent between foregoing and receiving treatment), and u2, the test/treatment utility threshold (the value u must take, given a negative test result, for the patient to be indifferent between foregoing and receiving treatment.

Use of influence diagrams to structure medical decisions.

Influence diagrams are compact representations of decision problems that are mathematically equivalent to decision trees. The authors present five important principles for structuring a decision as an influence diagram: 1) start at the value node and work back to the decision nodes; 2) draw the arcs in the direction that makes the probabilities easiest to assess; 3) use informational arcs to specify which events will have been observed at the time each decision is made; 4) ensure that missing arcs reflect intentional assertions about conditional independence and the timing of observations; and 5) ensure that there are no cycles in the influence diagram. They then build an influence diagram for the problem of staging non-small-cell lung cancer as an illustration. Influence diagrams offer several strengths for structuring medical decisions. They represent graphically and compactly the probabilistic relationships between parameters in the model. Influence diagrams also allow the model to be structured in a fashion that eases the necessary probability assessments, regardless of whether the assessments are based on available evidence or on expert judgment. Influence diagrams provide an important complement to decision trees, especially for representing probabilistic relationships among variables in a decision model.

A normative analytic framework for development of practice guidelines for specific clinical populations.

BACKGROUND: A central problem in practice guideline development is how to develop guidelines that appropriately account for variations in clinical populations and practice settings. Despite recognition of this problem, there is no formal mechanism for assessing what the need is for flexibility in guidelines, or for deciding how to incorporate such flexibility into recommendations. OBJECTIVE: This research sought to provide a formal basis to determine when clinical circumstances vary sufficiently that guideline recommendations should differ, how recommendations should be tailored for a specific clinical setting, and whether the benefit associated with such site-specific guidelines justifies the expense of their development. RESULTS: The authors describe an approach for estimating the maximum health benefit that developers can obtain by eliminating uncertainty about differences in the patient populations and practice settings in which a guideline will be used. This estimate, the expected value of customization, provides a mechanism to evaluate the cost-effectiveness of the development of site-specific guidelines that account explicitly for variation in clinical circumstances. Application of this method to the development of screening guidelines for human immunodeficiency virus (HIV) infection indicates that the development of site-specific guidelines potentially is cost-effective. Site-specific guidelines either improve, or leave unchanged, the efficiency of HIV screening; whether they increase or decrease total expenditures and health benefits depends on the choice of a cost-effectiveness threshold, and the clinical problem. CONCLUSIONS: Development of guideline recommendations based on decision models provides a normative approach for evaluating the need for and the cost-effectiveness of site-specific guidelines that have been tailored to specific practice settings. Such site-specific guidelines can improve substantially the expected health benefit and the economic efficiency of practice guidelines.

Choice-matching preference reversals in health outcome assessments.

BACKGROUND: Health outcome utility assessments generally assume procedural invariance. Preference reversals violating procedural invariance occur in economic scenarios when the assessment process shifts from a choice to a fill-in-the-blank task. PURPOSE: To determine if similar reversals occur in utility assessments. METHODS: One hundred thirty-six volunteer subjects completed 6 preference assessments of 4 personal health scenarios. Patients responded to otherwise identical tasks using either choice or fill-in-the-blank processes in a randomized crossover design. The authors determined the percentage of subjects preferring, or inferred to prefer, a given choice. RESULTS: Preference reversals occurred in all assessment scenarios. CONCLUSIONS: These preference reversals are a potential source of confusion for utility assessment and informed consent. They could be manipulated to achieve ends other than the best interest of patients. Anchoring or the prominence hypothesis may explain these findings.