Conducting a Discrete-Choice Experiment Study Following Recommendations for Good Research Practices: An Application for Eliciting Patient Preferences for Diabetes Treatments.

OBJECTIVES: To consolidate and illustrate good research practices in health care to the application and reporting of a study measuring patient preferences for type 2 diabetes mellitus medications, given recent methodological advances in stated-preference methods. METHODS: The International Society for Pharmacoeconomics and Outcomes Research good research practices and other recommendations were used to conduct a discrete-choice experiment. Members of a US online panel with type 2 diabetes mellitus completed a Web-enabled, self-administered survey that elicited choices between treatment pairs with six attributes at three possible levels each. A D-efficient experimental design blocked 48 choice tasks into three 16-task surveys. Preference estimates were obtained using mixed logit estimation and were used to calculate choice probabilities. RESULTS: A total of 552 participants (51% males) completed the survey. Avoiding 90 minutes of nausea was valued the highest (mean -10.00; 95% confidence interval [CI] -10.53 to -9.47). Participants wanted to avoid low blood glucose during the day and/or night (mean -3.87; 95% CI -4.32 to -3.42) or one pill and one injection per day (mean -7.04; 95% CI -7.63 to -6.45). Participants preferred stable blood glucose 6 d/wk (mean 4.63; 95% CI 4.15 to 5.12) and a 1% decrease in glycated hemoglobin (mean 5.74; 95% CI 5.22 to 6.25). If cost increased by $1, the probability that a treatment profile would be chosen decreased by 1%. CONCLUSIONS: These results are consistent with the idea that people have strong preferences for immediate consequences of medication. Despite efforts to produce recommendations, ambiguity surrounding good practices remains and various judgments need to be made when conducting stated-preference studies. To ensure transparency, these judgments should be described and justified.

Physicians' preferences for bone metastases treatments in France, Germany and the United Kingdom.

BACKGROUND: Several bone-targeted agents (BTAs) are available for preventing skeletal-related events (SREs), but they vary in terms of efficacy, safety and mode of administration. This study assessed data on European physicians' treatment preferences for preventing SREs in patients with bone metastases from solid tumours. METHODS: Physicians completed a web-based discrete-choice experiment survey of 10 choices between pairs of profiles of hypothetical BTAs for a putative patient. Each profile included five attributes within a pre-defined range (primarily based on existing BTAs' prescribing information): time (months) until the first SRE; time (months) until worsening of pain; annual risk of osteonecrosis of the jaw (ONJ); annual risk of renal impairment; and mode of administration. Choice questions were developed using an experimental design with known statistical properties. A separate main-effects random parameters logit model was estimated for each country and provided the relative preference for the treatment attributes in the study. RESULTS: A total of 191 physicians in France, 192 physicians in Germany, and 197 physicians in the United Kingdom completed the survey. In France and the United Kingdom, time until the first SRE and risk of renal impairment were the most important attributes; in Germany, time until the first SRE and delay in worsening of pain were the most important. In all countries, a 120-min infusion every 4 weeks was the least preferred mode of administration (p < 0.05) and the annual risk of ONJ was judged to be the least important attribute. CONCLUSIONS: When making treatment decisions regarding the choice of BTA, delaying the onset of SREs/worsening of pain and reducing the risk of renal impairment are the primary objectives for physicians.

Statistical Methods for the Analysis of Discrete Choice Experiments: A Report of the ISPOR Conjoint Analysis Good Research Practices Task Force.

Conjoint analysis is a stated-preference survey method that can be used to elicit responses that reveal preferences, priorities, and the relative importance of individual features associated with health care interventions or services. Conjoint analysis methods, particularly discrete choice experiments (DCEs), have been increasingly used to quantify preferences of patients, caregivers, physicians, and other stakeholders. Recent consensus-based guidance on good research practices, including two recent task force reports from the International Society for Pharmacoeconomics and Outcomes Research, has aided in improving the quality of conjoint analyses and DCEs in outcomes research. Nevertheless, uncertainty regarding good research practices for the statistical analysis of data from DCEs persists. There are multiple methods for analyzing DCE data. Understanding the characteristics and appropriate use of different analysis methods is critical to conducting a well-designed DCE study. This report will assist researchers in evaluating and selecting among alternative approaches to conducting statistical analysis of DCE data. We first present a simplistic DCE example and a simple method for using the resulting data. We then present a pedagogical example of a DCE and one of the most common approaches to analyzing data from such a question format-conditional logit. We then describe some common alternative methods for analyzing these data and the strengths and weaknesses of each alternative. We present the ESTIMATE checklist, which includes a list of questions to consider when justifying the choice of analysis method, describing the analysis, and interpreting the results.

A Framework for Incorporating Patient Preferences Regarding Benefits and Risks into Regulatory Assessment of Medical Technologies.

BACKGROUND: In response to 2012 guidance in which the US Food and Drug Administration's (FDA) Center for Devices and Radiological Health (CDRH) stated the importance of patient-centric measures in regulatory benefit-risk assessments, the Medical Device Innovation Consortium (MDIC) initiated a project. The project was used to develop a framework to help the Food and Drug Administration (FDA) and industry sponsors understand how patient preferences regarding benefit and risk might be integrated into the review of innovative medical devices. METHODS: A public-private partnership of experts from medical device industry, government, academia and non-profits collaborated on development of the MDIC patient centered benefit-risk framework. RESULTS: The MDIC Framework examines what patient preference information is and the potential use and value of patient preference information in the regulatory process and across the product development life cycle. The MDIC Framework also includes a catalog of patient preference assessment methods and an agenda for future research to advance the field. CONCLUSIONS: This article discusses key concepts in patient preference assessment of particular importance for regulators and researchers that are addressed in the MDIC Framework for patient centered benefit-risk assessment as well as the unique public-private collaboration that led its development.

Stated Preference for Cancer Screening: A Systematic Review of the Literature, 1990-2013.

INTRODUCTION: Stated-preference methods provide a systematic approach to quantitatively assess the relative preferences for features of cancer screening tests. We reviewed stated-preference studies for breast, cervical, and colorectal cancer screening to identify the types of attributes included, the use of questions to assess uptake, and whether gaps exist in these areas. The goal of our review is to inform research on the design and promotion of public health programs to increase cancer screening. METHODS: Using the PubMed and EconLit databases, we identified studies published in English from January 1990 through July 2013 that measured preferences for breast, cervical, and colorectal cancer screening test attributes using conjoint analysis or a discrete-choice experiment. We extracted data on study characteristics and results. We categorized studies by whether attributes evaluated included screening test, health care delivery characteristics, or both. RESULTS: Twenty-two studies met the search criteria. Colorectal cancer was the most commonly studied cancer of the 3. Fifteen studies examined only screening test attributes (efficacy, process, test characteristics, and cost). Two studies included only health care delivery attributes (information provided, staff characteristics, waiting time, and distance to facility). Five studies examined both screening test and health care delivery attributes. Overall, cancer screening test attributes had a significant effect on a patient's selection of a cancer screening test, and health care delivery attributes had mixed effects on choice. CONCLUSION: A growing number of studies examine preferences for cancer screening tests. These studies consistently find that screening test attributes, such as efficacy, process, and cost, are significant determinants of choice. Fewer studies have examined the effect of health care delivery attributes on choice, and the results from these studies are mixed. There is a need for additional studies on the barriers to cancer screening uptake, including health care delivery attributes, and the effect of education materials on preferences.

Physicians' preferences for bone metastases drug therapy in the United States.

OBJECTIVE: Several characteristics of bone-targeted agents are considered when making treatment decisions. This study evaluated physicians' therapy preferences for preventing skeletal-related events (SREs) in patients with bone metastases secondary to solid tumors. METHODS: A Web-enabled, discrete-choice experiment online survey was conducted among physicians who treated patients with bone metastases and solid tumors in the United States. Respondents chose between pairs of hypothetical medications defined by combinations of six attributes at varying levels for two hypothetical patients. Preference weights for attribute levels were estimated using a random-parameters logit model. RESULTS: In total, 200 physicians completed the survey. Their mean age was 52 years, 57% were in practice for more than 15 years, 37% were oncologists, and 65% treated 10 or fewer patients with bone metastases weekly. Out-of-pocket cost to patients was the most important attribute overall. Among clinical outcomes, time to first SRE and risk of renal impairment were the most important attributes. Statistically significant preferences were observed for all attribute levels for time to first SRE, risk of renal impairment, and mode of administration. Predicted choice probability analysis showed that physicians preferred a hypothetical medication with attributes similar to those of denosumab over one with attributes similar to those of zoledronic acid. CONCLUSIONS: Physicians indicated that clinical attributes are important when considering bone-targeting therapy for bone metastases, but consistent with the current health care landscape, patient out-of-pocket cost was the most important. With health care costs being increasingly shifted to patients, physicians require accurate information about co-pays and assistance programs to avoid patients receiving less costly, yet potentially inferior, treatment.

Patients' preferences for bone metastases treatments in France, Germany and the United Kingdom.

PURPOSE: The aim of this study was to assess patients' preferences for efficacy, safety, and mode of administration in relation to available bone-targeted agents (BTA) for the prevention of skeletal-related events (SREs) associated with bone metastases in Europe. METHODS: Adults in France (n = 159), Germany (n = 166), and the United Kingdom (UK; n = 159) with a self-reported physician diagnosis of bone metastases secondary to a solid tumour completed an online discrete- choice experiment survey of ten questions, choosing between pairs of hypothetical BTA profiles. Profiles were defined by five treatment attributes: delay of first SRE, delay of worsening of pain, annual risk of osteonecrosis of the jaw (ONJ), annual risk of renal impairment, and mode of administration. Profiles were generated using an experimental design with known statistical properties. A main-effects random parameters logit (RPL) model was applied to relate participants' choices to the characteristics of the BTA profiles. RESULTS: The most important treatment attributes for patients across all three countries were time until first SRE, annual risk of renal complications and time until pain worsening. For these attributes, better levels of outcomes were significantly preferred to worse levels (p < 0.05). A 120-minutes infusion every 4 weeks was the least preferred mode of administration. Risk of ONJ was judged by patients in the UK and Germany to be the least important attribute. CONCLUSIONS: Patients consider delaying SREs, avoiding renal impairment and delaying pain worsening as the most important goals to consider when selecting treatment to prevent the bone complications commonly associated with bone metastases.

Incorporating patient-preference evidence into regulatory decision making.

BACKGROUND: Patients have a unique role in deciding what treatments should be available for them and regulatory agencies should take their preferences into account when making treatment approval decisions. This is the first study designed to obtain quantitative patient-preference evidence to inform regulatory approval decisions by the Food and Drug Administration Center for Devices and Radiological Health. METHODS: Five-hundred and forty United States adults with body mass index (BMI) ≥ 30 kg/m(2) evaluated tradeoffs among effectiveness, safety, and other attributes of weight-loss devices in a scientific survey. Discrete-choice experiments were used to quantify the importance of safety, effectiveness, and other attributes of weight-loss devices to obese respondents. A tool based on these measures is being used to inform benefit-risk assessments for premarket approval of medical devices. RESULTS: Respondent choices yielded preference scores indicating their relative value for attributes of weight-loss devices in this study. We developed a tool to estimate the minimum weight loss acceptable by a patient to receive a device with a given risk profile and the maximum mortality risk tolerable in exchange for a given weight loss. For example, to accept a device with 0.01 % mortality risk, a risk tolerant patient will require about 10 % total body weight loss lasting 5 years. CONCLUSIONS: Patient preference evidence was used make regulatory decision making more patient-centered. In addition, we captured the heterogeneity of patient preferences allowing market approval of effective devices for risk tolerant patients. CDRH is using the study tool to define minimum clinical effectiveness to evaluate new weight-loss devices. The methods presented can be applied to a wide variety of medical products. This study supports the ongoing development of a guidance document on incorporating patient preferences into medical-device premarket approval decisions.

Estimating the value of medical treatments to patients using probabilistic multi criteria decision analysis.

BACKGROUND: Estimating the value of medical treatments to patients is an essential part of healthcare decision making, but is mostly done implicitly and without consulting patients. Multi criteria decision analysis (MCDA) has been proposed for the valuation task, while stated preference studies are increasingly used to measure patient preferences. In this study we propose a methodology for using stated preferences to weigh clinical evidence in an MCDA model that includes uncertainty in both patient preferences and clinical evidence explicitly. METHODS: A probabilistic MCDA model with an additive value function was developed and illustrated using a case on hypothetical treatments for depression. The patient-weighted values were approximated with Monte Carlo simulations and compared to expert-weighted results. Decision uncertainty was calculated as the probability of rank reversal for the first rank. Furthermore, scenario analyses were done to assess the relative impact of uncertainty in preferences and clinical evidence, and of assuming uniform preference distributions. RESULTS: The patient-weighted values for drug A, drug B, drug C, and placebo were 0.51 (95% CI: 0.48 to 0.54), 0.51 (95% CI: 0.48 to 0.54), 0.54 (0.49 to 0.58), and 0.15 (95% CI: 0.13 to 0.17), respectively. Drug C was the most preferred treatment and the rank reversal probability for first rank was 27%. This probability decreased to 18% when uncertainty in performances was not included and increased to 41% when uncertainty in criterion weights was not included. With uniform preference distributions, the first rank reversal probability increased to 61%. The expert-weighted values for drug A, drug B, drug C, and placebo were 0.67 (95% CI: 0.65 to 0.68), 0.57 (95% CI: 0.56 to 0.59), 0.67 (95% CI: 0.61 to 0.71), and 0.19 (95% CI: 0.17 to 0.21). The rank reversal probability for the first rank according to experts was 49%. CONCLUSIONS: Preferences elicited from patients can be used to weigh clinical evidence in a probabilistic MCDA model. The resulting treatment values can be contrasted to results from experts, and the impact of uncertainty can be quantified using rank probabilities. Future research should focus on integrating the model with regulatory decision frameworks and on including other types of uncertainty.

Patient preferences for treatments to delay bone metastases.

BACKGROUND: Most patients with advanced prostate cancer (PCa) develop bone metastases (BM) and present with bone complications like fracture. Bone-targeted agents that prevent metastasis-induced bone complications can cause adverse events. Understanding how patients view treatment options may optimize care. This study aimed to quantify how PCa patients value a hypothetical treatment that delays BM but can cause osteonecrosis of the jaw (ONJ). The study also assessed the value patients place on avoiding metastasis-induced bone complications versus increased survival. METHODS: PCa patients from the United Kingdom (n = 201) and Sweden (n = 200) on androgen-deprivation therapy or hormone therapy for ≥ 3 years completed a 10-question discrete-choice-experiment survey examining whether patients would accept a BM-delaying treatment. Two time-tradeoff questions assessed patients' willingness to tradeoff between survival and bone complications. Percentages of patients choosing treatment were summarized by levels of treatment efficacy and ONJ risk. Odds ratios from a logit model were used to evaluate how patient and medication characteristics affected treatment choice. Proportions of patients choosing each tradeoff scenario were calculated. RESULTS: A majority of patients accepted treatment at the lowest benefit level (5-month BM delay) and highest risk level (9% ONJ risk). PCa symptoms and prior treatment affected patient preferences. Nearly 80% of patients would tradeoff at least 3 months of survival to avoid bone complications. CONCLUSIONS: PCa patients in the U.K and Sweden may value a medication that delays BM, despite the risk of ONJ. Furthermore, patients were willing to tradeoff up to 5 months of survival for prevention of bone complications.

Understanding the relative importance of preserving functional abilities in Alzheimer's disease in the United States and Germany.

PURPOSE: To estimate the relative importance that Alzheimer's disease (AD) caregivers in the United States and Germany place on preserving patients' ability to perform activities of daily living. METHODS: US and German residents providing care for a person with AD completed an online preference survey. Each respondent completed five best-worst scaling questions. Each question related to five of 10 activities from the Disability Assessment for Dementia scale. Preference weights, indicating the relative importance of preserving the ability to perform these 10 activities for 36 months, were estimated using maximum-difference scaling. A separate model was estimated for each country. RESULTS: Four hundred and three US and 400 German caregivers completed the survey. In both countries, preserving a patients' ability to use the toilet without accidents was the most important activity and handling money was the least important activity. There were few differences between US and German caregivers in the relative importance across activities. CONCLUSIONS: Caregivers generally placed greater importance on preserving basic activities of daily living than on preserving instrumental activities of daily living. Understanding differences in the relative importance of functional items in the DAD may contribute to a better understanding of the benefits of different AD treatment and support measures.

Conjoint analysis applications in health--a checklist: a report of the ISPOR Good Research Practices for Conjoint Analysis Task Force.

BACKGROUND: The application of conjoint analysis (including discrete-choice experiments and other multiattribute stated-preference methods) in health has increased rapidly over the past decade. A wider acceptance of these methods is limited by an absence of consensus-based methodological standards. OBJECTIVE: The International Society for Pharmacoeconomics and Outcomes Research (ISPOR) Good Research Practices for Conjoint Analysis Task Force was established to identify good research practices for conjoint-analysis applications in health. METHODS: The task force met regularly to identify the important steps in a conjoint analysis, to discuss good research practices for conjoint analysis, and to develop and refine the key criteria for identifying good research practices. ISPOR members contributed to this process through an extensive consultation process. A final consensus meeting was held to revise the article using these comments, and those of a number of international reviewers. RESULTS: Task force findings are presented as a 10-item checklist covering: 1) research question; 2) attributes and levels; 3) construction of tasks; 4) experimental design; 5) preference elicitation; 6) instrument design; 7) data-collection plan; 8) statistical analyses; 9) results and conclusions; and 10) study presentation. A primary question relating to each of the 10 items is posed, and three sub-questions examine finer issues within items. CONCLUSIONS: Although the checklist should not be interpreted as endorsing any specific methodological approach to conjoint analysis, it can facilitate future training activities and discussions of good research practices for the application of conjoint-analysis methods in health care studies.

Quantitative Benefit-Risk Assessment: State of the Practice Within Industry.

BACKGROUND: Benefit-risk assessments for medicinal products and devices have advanced significantly over the past decade. The purpose of this study was to characterize the extent to which the life sciences industry is utilizing quantitative benefit-risk assessment (qBRA) methods. METHODS: Semi-structured interviews were conducted with a sample of industry professionals working in drug and/or medical device benefit-risk assessments (n = 20). Questions focused on the use, timing, and impact of qBRA; implementation challenges; and future plans. Interviews were recorded, transcribed, and coded for thematic analysis. RESULTS: While most surveyed companies had applied qBRA, application was limited to a small number of assets-primarily to support internal decision-making and regulatory submissions. Positive impacts associated with use included improved team decision-making and communication. Multi-criteria decision analysis and discrete choice experiment were the most frequently utilized qBRA methods. A key challenge of qBRA use was the lack of clarity regarding its value proposition. Championing by senior company leadership and receptivity of regulators to such analyses were cited as important catalysts for successful adoption of qBRA. Investment in qBRA methods, via capability building and pilot studies, was also under way in some instances. CONCLUSION: qBRA application within this sample of life sciences companies was widespread, but concentrated in a small fraction of assets. Its use was primarily for internal decision-making or regulatory submissions. While some companies had plans to build further capacity in this area, others were waiting for further regulatory guidance before doing so.

Patient-Centered Identification of Meaningful Regulatory Endpoints for Medical Devices to Treat Parkinson's Disease.

Introduction. A growing literature has developed on identifying outcomes that matter to patients. This study demonstrates an approach involving patient and regulatory perspectives to identify outcomes that are meaningful in the context of medical devices for Parkinson's disease (PD). Methods. A systematic process was used for specifying relevant regulatory endpoints by synthesizing inputs of various sources and stakeholders. First, a literature review was conducted to identify important benefits, risks, and other considerations for medical devices to treat PD; patient discussion groups (n = 6) were conducted to refine the list of considerations, followed by a survey (n = 29) to prioritize them; and patient and Food and Drug Administration (FDA) reviewers informed specification of the final endpoints. Two FDA clinicians gave clinical and regulatory perspectives at each step. Results. Movement symptoms were ranked as most important (ranked 1 or 2 by 72% of participants) and psychological and cognitive symptoms as the next most important (ranked 1 or 2 by 52% of participants). Within movement symptoms, falls, impaired movement, bradykinesia, resting tremor, stiffness, and rigidity were ranked highly. Overall, nine attributes were identified and prioritized as patient-centric for use in clinical trial design and quantitative patient preference studies. These attributes were benefits and risks related to therapeutics for PD as well as other considerations, including time until a medical device is available for patient use. Discussion. This prospective approach identified meaningful and relevant benefits, risks, and other considerations that may be used for clinical trial design and quantitative patient preference studies. Although PD was the focus of this study, the approach can be used to study patient perspectives about other disease or treatment areas.

Quantifying women's stated benefit-risk trade-off preferences for IBS treatment outcomes.

BACKGROUND: The Food and Drug Administration, currently, is exploring quantitative benefit-risk methods to support regulatory decision-making. A scientifically valid method for assessing patients' benefit-risk trade-off preferences is needed to compare risks and benefits in a common metric. OBJECTIVES: The study aims to quantify the maximum acceptable risk (MAR) of treatment-related adverse events (AEs) that women with diarrhea-predominant irritable bowel syndrome (IBS) are willing to accept in exchange for symptom relief. RESEARCH DESIGN: A stated-choice survey was used to elicit trade-off preferences among constructed treatment profiles, each defined by symptom severity and treatment-related AEs. Symptom attributes included frequency of abdominal pain and discomfort, frequency of diarrhea, and frequency of urgency. AE attributes included frequency of mild-to-moderate constipation and the risk of four possible serious AEs. SUBJECTS: A Web-enabled survey was administered to 589 female US residents at least 18 years of age with a self-reported diagnosis of diarrhea-predominant IBS. MEASURES: Preference weights and MAR were estimated using mixed-logit methods. RESULTS: SUBJECTS were willing to accept higher risks of serious AEs in return for treatments offering better symptom control. For an improvement from the lowest to the highest of four benefit levels, subjects were willing to tolerate a 2.65% increase in impacted-bowel risk, but only a 1.34% increase in perforated-bowel risk. CONCLUSIONS: Variation in MARs across AE types is consistent with the relative seriousness of the AEs. Stated-preference methods offer a scientifically valid approach to quantifying benefit-risk trade-off preferences that can be used to inform regulatory decision-making.

Using the incremental net benefit framework for quantitative benefit-risk analysis in regulatory decision-making--a case study of alosetron in irritable bowel syndrome.

OBJECTIVE: There is consensus that a more transparent, explicit, and rigorous approach to benefit-risk evaluation is required. The objective of this study is to evaluate the incremental net benefit (INB) framework for undertaking quantitative benefit-risk assessment by performing a quantitative benefit-risk analysis of alosetron for the treatment of irritable bowel syndrome from the patients' perspective. METHODS: A discrete event simulation model was developed to determine the INB of alosetron relative to placebo, calculated as "relative value-adjusted life-years (RVALYs)." RESULTS: In the base case analysis, alosetron resulted in a mean INB of 34.1 RVALYs per 1000 patients treated relative to placebo over 52 weeks of treatment. Incorporating parameter uncertainty into the model, probabilistic sensitivity analysis revealed a mean INB of 30.4 (95% confidence interval 15.9-45.4) RVALYs per 1000 patients treated relative to placebo over 52 weeks of treatment. Overall, there was >99% chance that both the incremental benefit and incremental risk associated with alosetron are greater than placebo. As hypothesized, the INB of alosetron was greatest in patients with the worst quality of life experienced at baseline. The mean INB associated with alosetron in patients with mild, moderate, and severe symptoms at baseline was 17.97 (-0.55 to 36.23), 29.98 (17.05-43.37), and 35.98 (23.49-48.77) RVALYs per 1000 patients treated, respectively. CONCLUSIONS: This study demonstrates the potential utility of applying the INB framework to real-life decision-making, and the ability to use simulation modeling incorporating outcomes data from different sources as a benefit-risk decision aid.

Patients' benefit-risk preferences for chronic idiopathic thrombocytopenic purpura therapies.

BACKGROUND: Idiopathic thrombocytopenic purpura (ITP) primarily is a disorder of adults characterized by autoantibody-induced platelet destruction and reduced platelet production, leading to a low peripheral blood platelet count. The long-term management of many patients with chronic ITP is unsatisfactory, largely due to the variable efficacy and risks of severe adverse effects associated with current treatment options. OBJECTIVE: To estimate patients' benefit-risk preferences for treatments for ITP. METHODS: Patients' adverse event risk tolerance and the levels of benefit required to offset possible risks were evaluated using choice-format conjoint analysis. Subjects chose between pairs of hypothetical treatment alternatives defined by probability of achieving safe platelet levels, need for corticosteroids, mode of administration, risk of rebound, risk of elevated liver enzyme levels, and risk of thromboembolism. RESULTS: In this study, we demonstrate that patients have clear and measurable benefit-risk preferences that physicians should consider when discussing treatment options with their patients. Patients were willing to accept significant risks of adverse events in return for an increase in the probability of achieving safe platelet levels, to avoid corticosteroids, and for more convenient administration. Patients were willing to accept significant risks of rebound and elevated liver enzymes for improvements in outcomes. CONCLUSIONS: These results demonstrate that patients with ITP are willing to accept treatment-related risks in exchange for improvements in treatment efficacy and administration attributes and suggest the importance of considering a patient's benefit-risk preferences during discussions of therapeutic options.

Who pays attention in stated-choice surveys?

Responses of inattentive or inconsistent subjects in stated-choice (SC) surveys can lead to imprecise or biased estimates. Several SC studies have investigated inconsistency and most of these studies dropped subjects who were inconsistent. However, none of these studies reported who is more likely to fail consistency tests. We investigated the effect of the personal characteristics and task complexity on preference inconsistency in eight different SC surveys. We found that white, higher-income and better-educated female subjects were less likely to fail consistency tests. Understanding the characteristics of subjects who are inattentive to the choice task may help in designing and pre-testing instruments that work effectively for a wider range of subjects.

Estimating importance weights for the IWQOL-Lite using conjoint analysis.

PURPOSE: Our objective was to estimate preference-based weights for the IWQOL-Lite that reflect the relative importance overweight and obese people place on the domains included in the instrument. METHODS: US residents, 18 years of age or older, who are overweight (BMI=25.0-29.9) or obese (BMI>or=30) completed an online survey instrument consisting of 12 choice questions. The survey included eight attributes: problems doing usual daily activities, physical symptoms, worry about health, low self-esteem, sexual problems, problems moving around or sitting in public places, teasing or discrimination, and problems at work. Ordered probit was used to estimate importance weights for the attributes and levels. RESULTS: Five hundred and two subjects completed the survey. Sexual problem was the most important attribute. The remaining attributes can be ranked on the order of importance as follows: low self-esteem, physical symptoms, daily activities, teasing or discrimination, moving around or sitting, problems at work, and worry about health. CONCLUSIONS: Our results confirm previous findings that weighting the individual items in the IWQOL-Lite by the importance of outcomes to overweight and obese subjects may provide a more meaningful evaluation of the effect of changes in weight on patient well-being than a nonpreference-based measure of HRQOL.

Using conjoint analysis to estimate healthy-year equivalents for acute conditions: an application to vasomotor symptoms.

OBJECTIVE: Conventional standard gamble and time trade-off methods may be inappropriate for eliciting preferences for some health states because both require subjects to make trade-offs between a morbid health state and death. Thus, the objective of this study is to demonstrate the use of conjoint analysis to obtain time trade-off estimates of healthy-year equivalents (HYEs) for clinically relevant durations and severities of acute, self-limiting, or nonfatal conditions such as vasomotor symptoms. METHODS: A self-administered, web-enabled, graded-pairs conjoint-analysis survey was developed to elicit women's preferences for reducing the frequency and severity of vasomotor symptoms (daytime hot flushes and night sweats). Observed trade-offs between symptom duration and symptom relief were used to calculate HYEs for different severities and durations of vasomotor symptoms. RESULTS: A total of 523 women with a mean age of 52 years completed the survey. For these women, an improvement from severe to moderate vasomotor symptoms yields a gain of 4.44 HYEs, and an improvement from moderate to mild vasomotor symptoms over 1 year yields a gain of 4.62 HYEs over a period of 7 years. HYE gains for symptom relief are larger for younger women than for older women. CONCLUSIONS: Conjoint analysis is a feasible method for estimating HYEs for acute, self-limiting, or nonfatal conditions. This approach may provide an alternative utility-elicitation method when conventional standard gamble and time trade-off methods are inappropriate to the decision context.