Discrete Choice Experiments in Health State Valuation: A Systematic Review of Progress and New Trends.

BACKGROUND: Discrete choice experiments (DCEs) are increasingly used in health state valuation studies. OBJECTIVE: This systematic review updates the progress and new findings of DCE studies in the health state valuation, covering the period since the review of June 2018 to November 2022. The review reports the methods that are currently being used in DCE studies to value health and study design characteristics, and, for the first time, reviews DCE health state valuation studies published in the Chinese language. METHODS: English language databases PubMed and Cochrane, and Chinese language databases Wanfang and CNKI were searched using the self-developed search terms. Health state valuation or methodology study papers were included if the study used DCE data to generate a value set for a preference-based measure. Key information extracted included DCE study design strategies applied, methods for anchoring the latent coefficient on to a 0-1 QALY scale and data analysis methods. RESULTS: Sixty-five studies were included; one Chinese language publication and 64 English language publications. The number of health state valuation studies using DCE has rapidly increased in recent years and these have been conducted in more countries than prior to 2018. Wide usage of DCE with duration attributes, D-efficient design and models accounting for heterogeneity has continued in recent years. Although more methodological consensus has been found than in studies conducted prior to 2018, this consensus may be driven by valuation studies for common measures with an international protocol (the 'model' valuation research). Valuing long measures with well-being attributes attracted attention and more realistic design strategies (e.g., inconstant time preference, efficient design and implausible states design) were identified. However, more qualitative and quantitative methodology study is still necessary to evaluate the effect of those new methods. CONCLUSIONS: The use of DCEs in health state valuation continues to grow dramatically and the methodology progress makes the method more reliable and pragmatic. However, study design is driven by international protocols and method selection is not always justified. There is no gold standard for DCE design, presentation format or anchoring method. More qualitative and quantitative methodology study is recommended to evaluate the effect of new methods before researchers make methodology decisions.

Disease-specific assessment of Vision Impairment in Low Luminance in age-related macular degeneration - a MACUSTAR study report.

BACKGROUND/AIMS: To further validate the Vision Impairment in Low Luminance (VILL) questionnaire, which captures visual functioning and vision-related quality of life (VRQoL) under low luminance, low-contrast conditions relevant to age-related macular degeneration (AMD). METHODS: The VILL was translated from German into English (UK), Danish, Dutch, French, Italian and Portuguese. Rasch analysis was used to assess psychometric characteristics of 716 participants (65% female, mean age 72±7 years, 82% intermediate AMD) from the baseline visit of the MACUSTAR study. In a subset of participants (n=301), test-retest reliability (intraclass correlation coefficient (ICC) and coefficient of repeatability (CoR)) and construct validity were assessed. RESULTS: Four items were removed from the VILL with 37 items due to misfit. The resulting Vision Impairment in Low Luminance with 33 items (VILL-33) has three subscales with no disordered thresholds and no misfitting items. No differential item functioning and no multidimensionality were observed. Person reliability and person separation index were 0.91 and 3.27 for the Vision Impairment in Low Luminance Reading Subscale (VILL-R), 0.87 and 2.58 for the Vision Impairment in Low Luminance Mobility Subscale (VILL-M), and 0.78 and 1.90 for the Vision Impairment in Low Luminance Emotional Subscale (VILL-E). ICC and CoR were 0.92 and 1.9 for VILL-R, 0.93 and 1.8 for VILL-M and 0.82 and 5.0 for VILL-E. Reported VRQoL decreased with advanced AMD stage (p<0.0001) and was lower in the intermediate AMD group than in the no AMD group (p≤0.0053). CONCLUSION: The VILL is a psychometrically sound patient-reported outcome instrument, and the results further support its reliability and validity across all AMD stages. We recommend the shortened version of the questionnaire with three subscales (VILL-33) for future use. TRIAL REGISTRATION NUMBER: NCT03349801.

Development of the Cystic Fibrosis Questionnaire-Revised-8 Dimensions: Estimating Utilities From the Cystic Fibrosis Questionnaire-Revised.

OBJECTIVES: Cystic fibrosis (CF) limits survival and negatively affects health-related quality of life (HRQOL). Cost-effectiveness analysis (CEA) may be used to make reimbursement decisions for new CF treatments; nevertheless, generic utility measures used in CEA, such as EQ-5D, are insensitive to meaningful changes in lung function and HRQOL in CF. Here we develop a new, CF disease-specific, preference-based utility measure based on the adolescent/adult version of the Cystic Fibrosis Questionnaire-Revised (CFQ-R), a widely used, CF-specific, patient-reported measure of HRQOL. METHODS: Blinded CFQ-R data from 4 clinical trials (NCT02347657, NCT02392234, NCT01807923, and NCT01807949) were used to identify discriminating items for a classification system using psychometric (eg, factor and Rasch) analyses. Thirty-two health states were selected for a time trade-off (TTO) exercise with a representative sample of the UK general population. TTO utilities were used to estimate a preference-based scoring algorithm by regression analysis (tobit models with robust standard errors clustered on participants with censoring at -1). RESULTS: A classification system with 8 dimensions (CFQ-R-8 dimensions; physical functioning, vitality, emotion, role functioning, breathing difficulty, cough, abdominal pain, and body image) was generated. TTO was completed by 400 participants (mean age, 47.3 years; 49.8% female). Among the regression models evaluated, the tobit heteroscedastic-ordered model was preferred, with a predicted utility range from 0.236 to 1, no logical inconsistencies, and a mean absolute error of 0.032. CONCLUSION: The CFQ-R-8 dimensions is the first disease-specific, preference-based scoring algorithm for CF, enabling estimation of disease-specific utilities for CEA based on the well-validated and widely used CFQ-R.

Hypothetical versus experienced health state valuation: a qualitative study of adult general public views and preferences.

OBJECTIVES: Responses from hypothetical and experienced valuation tasks of health-related quality of life differ, yet there is limited understanding of why these differences exist, what members of the public think about them, and acceptable resolutions. This study explores public understanding of, opinions on, and potential solutions to differences between hypothetical versus experienced responses, in the context of allocating health resources. METHODS: Six focus groups with 30 members of the UK adult public were conducted, transcribed verbatim, and analysed using framework analysis. Participants self-completed the EQ-5D-5L, before reporting the expected consequences of being in two hypothetical EQ-5D-5L health states for ten years. Second, participants were presented with prior results on the same task from a public (hypothetical) and patient (experienced) sample. Third, a semi-structured discussion explored participants': (1) understanding, (2) opinions, and (3) potential resolutions. RESULTS: Twenty themes emerged, clustered by the three discussion points. Most participants found imagining the health states difficult without experience, with those aligned to mental health harder to understand. Participants were surprised that health resource allocation was based on hypothetical responses. They viewed experienced responses as more accurate, but noted potential biases. Participants were in favour of better informing, but not influencing the public. Other solutions included incorporating other perspectives (e.g., carers) or combining/weighting responses. CONCLUSION: Members of the UK public appear intuitively not to support using potentially uninformed public values to hypothetical health states in the context of health resource allocation. Acceptable solutions involve recruiting people with greater experience, including other/combinations of views, or better informing respondents.

Estimation of a Canadian preference-based scoring algorithm for the Veterans RAND 12-Item Health Survey: a population survey using a discrete-choice experiment.

BACKGROUND: The Veterans RAND 12-Item Health Survey (VR-12) is a generic patient-reported outcome measure derived from the widely used 36- and 12-item Short Form Health Surveys. We aimed to estimate a Canadian preference-based scoring algorithm for the VR-12, enabling the derivation of health utility values for generating quality-adjusted life years (QALYs). METHODS: We conducted a discrete-choice experiment in a sample of the Canadian population in January and February 2019. Participants - recruited from a consumer research panel - completed an online survey, in English or French, that included 11 discrete-choice questions, each comprising 2 health profiles. We defined the health profiles using 8 VR-12 items and a duration attribute. Using conditional logit regressions, where each level of the respective VR-12 items was interacted with duration, we applied the coefficients to estimate health utility values interpretable on a scale of 0 (dead) to 1 (full health). Negative values reflect states considered worse than dead. RESULTS: A total of 3380 individuals completed the survey. Of these, 1688 (49.9%) were females, and 3101 (91.7%) completed the English version of the survey. Across all models, "feel downhearted and blue all of the time" and "pain interferes with your normal work extremely" were associated with the largest decrements in health utility. Excluding the 685 respondents (20.3%) who provided inconsistent responses had a negligible effect on the results. The recommended model, weighted to match population demographics, had health utility values ranging from -0.589 to 1.000. INTERPRETATION: Health utility values that reflect the preferences of the Canadian population can now be derived from responses to the VR-12. These values can be used to generate QALYs in future analyses.

Valuing child and adolescent health: a qualitative study on different perspectives and priorities taken by the adult general public.

BACKGROUND: Quantitative health preference research has shown that different "perspectives", defined here as who is imagined to be experiencing particular health states, impact stated preferences. This qualitative project aimed to elucidate this phenomenon, within the context of adults' valuation of child and adolescent health states. METHODS: Six focus groups with 30 members of the UK adult public were conducted between December 2019 and February 2020 and analysed using framework analysis. Each focus group had two stages. First, participants individually completed time trade-off tasks and a pairwise task (mirroring a discrete choice experiment without duration) for two EQ-5D-Y health states, assuming a series of perspectives: (a) themselves at current age; (b) another adult; (c) 10-year old child; (d) themselves as a 10-year old child. Second, a semi-structured discussion explored their responses. RESULTS: Participants' views were often heterogeneous, with some common themes. Qualitatively, participants expressed a different willingness to trade-off life years for a 10-year old child versus themselves or another adult, and this differed by the health profile and child imagined. The same health states were often viewed as having a different impact on utility for a 10-year old child than adults. Imagining a 10-year old child is difficult and there is variation in who is imagined. Participants found answering based on their own-adult perspective most acceptable. There were no strong preferences for prioritising child health over working-age adults' health. CONCLUSIONS: If an adult sample is used to value child- and adolescent-specific health states it is important to consider the perspective employed. Members of the adult public provide different responses when different perspectives are used due to differences in the perceived impact of the same health states. If adults are asked to imagine a child, we recommend that sampling is representative for parental status, since this can affect preferences.

Vignette-Based Utilities: Usefulness, Limitations, and Methodological Recommendations.

Health technology assessment agencies often prefer that utilities used to calculate quality-adjusted life years in cost-utility analyses (CUAs) are derived using standardized methods, such as generic preference-based measures completed by patients in clinical trials. However, there are situations when no standardized approach is feasible or appropriate for a specific medical condition or treatment that must be represented in a CUA. When this occurs, vignette-based methods are often used to estimate utilities. A vignette (sometimes called a "scenario," "health state description," "health state vignette," or "health state") is a description of a health state that is valued in a preference elicitation task to obtain a utility estimate. This method is sometimes the only feasible way to estimate utilities representing a concept that is important for a CUA. Consequently, vignette-based studies continue to be conducted and published, with the resulting utilities used in economic models to inform decision making about healthcare resource allocation. Despite the potential impact of vignette-based utilities on medical decision making, there is no published guidance or review of this methodology. This article provides recommendations for researchers, health technology assessment reviewers, and policymakers who may be deciding whether to use vignette-based methods, designing a vignette study, using vignette-based utilities in a CUA, or evaluating a CUA that includes vignette-based utilities. Recommendations are provided on: (A) when to use vignette-based utilities, (B) methods for developing vignettes, (C) valuing vignettes, (D) use of vignette-based utilities in models, and (E) limitations of vignette methods.

Adapting preference-based utility measures to capture the impact of cancer treatment-related symptoms.

It is important that patient-reported outcome (PRO) measures used to assess cancer therapies adequately capture the benefits and risks experienced by patients, particularly when adverse event profiles differ across therapies. This study explores the case for augmenting preference-based utility measures to capture the impact of cancer treatment-related symptoms. Additional cancer treatment-related items could be specific (e.g., rash) or global. While specific items are easier to describe and understand, their use may miss rarer symptoms and those that are currently unknown but will arise from future medical advancements. The appropriate number of additional items, the independence of those items, and their impact on the psychometric properties of the core instrument require consideration. Alternatively, a global item could encompass all potential treatment-related symptoms, of any treatments for any disease. However, such an item may not be well understood by general public respondents in valuation exercises. Further challenges include the decision about whether to generate de novo value sets for the modified instrument or to map to existing tariffs. The fluctuating and transient nature of treatment-related symptoms may be inconsistent with the methods used in conventional valuation exercises. Fluctuating symptoms could be missed by sub-optimal measure administration timing. The addition of items also poses double-counting risks. In summary, the addition of treatment-related symptom items could increase the sensitivity of existing utility measures to capture known and unknown treatment effects in oncology, while retaining the core domains. However, more research is needed to investigate the challenges, particularly regarding valuation.

Person-centred experiential therapy versus cognitive behavioural therapy delivered in the English Improving Access to Psychological Therapies service for the treatment of moderate or severe depression (PRaCTICED): a pragmatic, randomised, non-inferiority trial.

BACKGROUND: The UK Government's implementation in 2008 of the Improving Access to Psychological Therapies (IAPT) initiative in England has hugely increased the availability of cognitive behavioural therapy (CBT) for the treatment of depression and anxiety in primary care. Counselling for depression-a form of person-centred experiential therapy (PCET)-has since been included as an IAPT-approved therapy, but there is no evidence of its efficacy from randomised controlled trials (RCTs), as required for recommendations by the National Institute for Health and Care Excellence. Therefore, we aimed to examine whether PCET is cost effective and non-inferior to CBT in the treatment of moderate and severe depression within the IAPT service. METHODS: This pragmatic, randomised, non-inferiority trial was done in the Sheffield IAPT service in England and recruited participants aged 18 years or older with moderate or severe depression on the Clinical Interview Schedule-Revised. We excluded participants presenting with an organic condition, a previous diagnosis of personality disorder, bipolar disorder, or schizophrenia, drug or alcohol dependency, an elevated clinical risk of suicide, or a long-term physical condition. Eligible participants were randomly assigned (1:1), independently of the research team, and stratified by site with permuted block sizes of two, four, or six, to receive either PCET or CBT by use of a remote, web-based system that revealed therapy after patient details were entered. Those assessing outcomes were masked to treatment allocation. Participants were seen by appropriately trained PCET counsellors and CBT therapists in accordance with the IAPT service delivery model. Depression severity and symptomatology measured by the Patient Health Questionnaire-9 (PHQ-9) at 6 months post-randomisation was the primary outcome, with the PHQ-9 score at 12 months post-randomisation being a key secondary outcome. These outcomes were analysed in the modified intention-to-treat population, which comprised all randomly assigned patients with complete data, and the per-protocol population, which comprised all participants who did not switch from their randomised treatment and received between four and 20 sessions. Safety was analysed in all randomly assigned patients. The non-inferiority margin was set a priori at 2 PHQ-9 points. Patient safety was monitored throughout the course of therapy, adhering to service risk procedures for monitoring serious adverse events. This trial is registered at the ISRCTN Registry, ISRCTN06461651, and is complete. FINDINGS: From Nov 11, 2014, to Aug 3, 2018, 9898 patients were referred to step three treatments in the Sheffield IAPT service for common mental health problems, of whom 761 (7·7%) were referred to the trial. Of these, we recruited and randomly assigned 510 participants to receive either PCET (n=254) or CBT (n=256). In the PCET group, 138 (54%) participants were female and 116 (46%) were male, and 225 (89%) were White, 16 (6%) were non-White, and 13 (5%) had missing ethnicity data. In the CBT group, 155 (61%) participants were female and 101 (39%) were male, and 226 (88%) were White, 17 (7%) were non-White, and 13 (5%) had missing ethnicity data. The 6-month modified intention-to-treat analysis comprised 401 (79%) of the enrolled participants (201 in the PCET group; 200 in the CBT group) and the 12-month modified intention-to-treat analysis comprised 319 participants (167 in the PCET group; 152 in the CBT group). The 6-month per-protocol analysis comprised 298 participants (154 in the PCET group; 144 in the CBT group). At 6 months post-randomisation, PCET was non-inferior to CBT in the intention-to-treat population (mean PHQ-9 score 12·74 [SD 6·54] in the PCET group and 13·25 [6·35] in the CBT group; adjusted mean difference -0·35 [95% CI -1·53 to 0·84]) and in the per-protocol population (12·73 [SD 6·57] in the PCET group and 12·71 [6·33] in the CBT group; 0·27 [95% CI -1·08 to 1·62]). At 12 months post-randomisation, there was a significant adjusted between-group difference in mean PHQ-9 score in favour of CBT (1·73 [95% CI 0·26-3·19]), with a 95% CI exceeding the 2-point non-inferiority margin. There were two deaths, one death by suicide in the PCET group and one due to chronic obstructive pulmonary disease in the CBT group. Both were assessed by the responsible clinician to be unrelated to the trial. In terms of using emergency departments for depression-related events, four people (three in the PCET group; one in the CBT group) made more than a single use and six people (three in the PCET group; three in the CBT group) made a single use. One patient in the PCET group had inpatient treatment for a depression-related event. INTERPRETATION: This trial is the first to examine the two most frequently administered psychological therapies in the IAPT service. The finding of non-inferiority of PCET to CBT at 6 months supports the results from large, routine, non-randomised datasets from the IAPT programme. Given the high demand for psychological therapies and the need for patient choice, our findings suggest the need for continued investment in the training and delivery of PCET for improving short-term outcomes, but suggest that PCET might be inferior to CBT at 12 months. FUNDING: British Association for Counselling and Psychotherapy Research Foundation.

Evaluating the conduct and application of health utility studies: a review of critical appraisal tools and reporting checklists.

BACKGROUND: Published health utility studies are increasingly cited in cost-utility analyses to inform reimbursement decision-making. However, there is limited guidance for investigators looking to systematically evaluate the methodological quality of health utility studies or their applicability to decision contexts. OBJECTIVE: To describe how health utility concepts are reflected in tools intended for use with the health economic literature, particularly with respect to the evaluation of methodological quality and context applicability. METHODS: We reviewed the critical appraisal and reporting tools described in a 2012 report published by the Agency for Healthcare Research and Quality (AHRQ), supplemented with a keyword search of MEDLINE and EMBASE, to identify existing tools which include health utility constructs. From these tools, a list of relevant items was compiled and grouped into domain categories based on the methodological or applicability aspect they were directed toward. RESULTS: Of the 24 tools we identified, 12 contained items relevant to the evaluation of health utilities. Sixty-five items were considered relevant to the evaluation of quality, while 44 were relevant to the evaluation of applicability. Items were arranged into four domains: health state descriptions; selection and description of respondents; elicitation and measurement methods; and other considerations. CONCLUSION: As key inputs to cost-utility analyses, health utilities have the potential to significantly impact estimates of cost-effectiveness. Existing tools contain only general items related to the conduct or use of health utility studies. There is a need to develop tools that systematically evaluate the methodological quality and applicability of health utility studies.

Development of a New Quality of Life Measure for Duchenne Muscular Dystrophy Using Mixed Methods: The DMD-QoL.

OBJECTIVE: Based on concerns about existing patient-reported outcome measures (PROMs) for assessing quality of life (QoL) in Duchenne muscular dystrophy (DMD), we describe the mixed methods development of a new QoL PROM for use in boys and men with DMD: the DMD-QoL. METHODS: The DMD-QoL was developed in 3 stages. First, draft items were generated from 18 semistructured qualitative interviews with boys and men with DMD, analyzed using framework analysis. Second, cognitive debriefing interviews with patients (n = 10), clinicians (n = 8), and patients' parents (n = 10) were undertaken, and a reduced item set was selected and refined. Third, psychometric data on the draft items from a cross-sectional online survey (n = 102) and stakeholder input from patients and patients' parents were used to produce the final questionnaire. Patient and public involvement and engagement was embedded throughout the process. RESULTS: From an initial draft of 47 items, a revised set of 27 items was produced at stage 2, and this set was further refined at stage 3 to generate the DMD-QoL, a 14-item QoL PROM. The DMD-QoL is designed for use from 7 years of age by proxy report and from 10 years of age by self-report or proxy report. The final measure showed good psychometric properties. CONCLUSION: The DMD-QoL is a new 14-item QoL PROM for boys and men with DMD, with demonstrable content and face validity.

Valuation of SF-6Dv2 Health States in China Using Time Trade-off and Discrete-Choice Experiment with a Duration Dimension.

OBJECTIVES: Our objective was to generate a value set for the SF-6Dv2 using time trade-off (TTO) and a discrete-choice experiment with a duration dimension (DCETTO) in China. METHODS: A large representative sample of the Chinese general population was recruited from eight provinces/municipalities in China, stratified by age, sex, education level, and proportion of urban/rural residence. Respondents completed eight TTO tasks and ten DCETTO tasks during face-to-face interviews. Ordinary least squares (OLS), random-effects, fixed-effects, and Tobit models were used for TTO data, and conditional logit and mixed logit models were used for DCETTO. The monotonicity of model coefficients and the consistency of the predicted values according to intraclass correlation coefficient (ICC), mean absolute difference (MAD), and mean squared difference (MSD) were compared between the two approaches. RESULTS: In total, 3320 respondents (50.3% male; range 18-90 years) were recruited. The random-effects model and the conditional logit model were preferred for the TTO and DCETTO, respectively. The TTO values ranged from - 0.277 to 1, with 927 (4.94%) states considered as worse than dead (WTD). The corresponding range for DCETTO was - 0.535 to 1, with a higher WTD of 8.50%. DCETTO presented minor non-monotonicity with the coefficients in two dimensions. Values from the two approaches were highly consistent (ICC 0.9804, MAD 0.0588, MSD 0.0055), albeit those with DCETTO were slightly lower than those with TTO. The value set generated by TTO was preferred given the better monotonicity and the statistical significance of coefficients. CONCLUSIONS: The Chinese value set for the SF-6Dv2 was established based on the TTO approach, but the DCETTO also performed well. Minor issues of non-monotonicity did present for DCETTO.

What Is the Health and Well-Being Burden for Parents Living With a Child With ADHD in the United Kingdom?

Objective: To explore the burden associated with childhood ADHD in a large observational study. Methods: We recruited familes with at least one child (6-18 years) with ADHD via 15 NHS trusts in the UK, and collected data from all family members. We made careful adjustments to ensure a like-for-like comparison with two different control groups, and explored the impact of controlling for a positive parental/carer ADHD screen, employment, and relationship status. Results: We found significant negative impacts of childhood ADHD on parents'/carers' hours and quality of sleep, satisfaction with leisure time, and health-related quality of life (measured by the EuroQol-5D [EQ-5D]). We found a decrement in life satisfaction, mental well-being (as measured by the Short-Warwick Edinburgh Mental Well-Being Scale [S-WEMWBS]), and satisfaction with intimate relationships, but this was not always robust across the different control groups. We did not find any decrement in satisfaction with health, self-reported health status, or satisfaction with income. Conclusion: The study quantifies the impact on the health and well-being of parents living with a child with ADHD using a survey of families attending ADHD clinics in the United Kingdom.

Do Discrete Choice Experiments Approaches Perform Better Than Time Trade-Off in Eliciting Health State Utilities? Evidence From SF-6Dv2 in China.

OBJECTIVES: To explore the acceptability, consistency, and accuracy of eliciting health state utility values using discrete choice experiment (DCE) and DCE with life duration dimension (DCETTO) as compared with conventional time trade-off (TTO) by using the SF-6Dv2. METHODS: During face-to-face interviews, a representative sample of the general population in Tianjin, China, completed 8 TTO tasks and 10 DCE/DCETTO tasks, with the order of TTO and DCE/DCETTO being randomized. The fixed-effect model and conditional logit models were used for TTO and DCEs data estimation, respectively. Acceptability was assessed by self-reported difficulties in understanding/answering. Consistency was observed by the monotonicity of model coefficients. Accuracy was evaluated by investigating differences between observed and predicted TTO values using intraclass correlation coefficient, mean absolute difference, and root mean square difference. RESULTS: A total of 503 respondents (53.7% male; range, 18-86 years) were included, with comparable characteristics between respondents who completed DCE (N = 252) and DCETTO (N = 251). No significant difference was observed in self-reported difficulties among 3 approaches. The monotonicity of coefficients could not be achieved for 2 DCE approaches, even when combining the inconsistent levels. The health state utility values generated by DCE were generally higher than those generated by TTO, whereas DCETTO was lower than TTO. The TTO had a better prediction accuracy than the DCEs. CONCLUSIONS: Two DCE approaches are feasible for eliciting health state utility values; however, they are not considered to be easier to understand/answer than TTO. There are systematic differences in the health state utility values generated by 3 approaches. The issue of non-monotonicity from 2 DCE approaches remains a concern.

Developing a New Version of the SF-6D Health State Classification System From the SF-36v2: SF-6Dv2.

OBJECTIVE: The objective of this study was to develop the classification system for version of the SF-6D (SF-6Dv2) from the SF-36v2. SF-6Dv2 is an improved version of SF-6D, one of the most widely used generic measures of health for the calculation of quality-adjusted life years. STUDY DESIGN AND SETTING: A 3-step process was undertaken to generate a new classification system: (1) factor analysis to establish dimensionality; (2) Rasch analysis to understand item performance; and (3) tests of differential item function. To evaluate robustness, Rasch analyses were performed in multiple subsets of 2 large cross-sectional datasets from recently discharged hospital patients and online patient samples. RESULTS: On the basis of factor analysis, other psychometric evidence, cross-cultural considerations, and amenability to valuation, the 6-dimension classification used in SF-6D was maintained. SF-6Dv2 resulted in the following modifications to SF-6D: a simpler classification of physical function with clearer separation between levels; a more detailed 5-level description of role limitations; using negative wording to describe vitality; and using pain severity rather than pain interference. CONCLUSIONS: The SF-6Dv2 classification system describes more distinct levels of health than SF-6D, changes the descriptions used for a number of dimensions and provides clearer wording for health state valuation. The second stage of the study has developed a utility value set using discrete choice methods so that the measure can be used in health technology assessment. Further work should investigate the psychometric characteristics of the new instrument.

The Simplified Chinese version of SF-6Dv2: translation, cross-cultural adaptation and preliminary psychometric testing.

PURPOSE: To translate, cross-culturally adapt and preliminarily test the Simplified Chinese version of SF-6Dv2 among the Chinese general population. METHODS: The translation followed the international guidelines. Face-to-face cognitive debriefing was carried out in a small sample of the Chinese general population, using both think-aloud and retrospective probing methods. Preliminary psychometric properties (including acceptability, ceiling/floor effect and known-group validity) were investigated using a cross-sectional survey which was conducted in a representative sample of the general population in Tianjin, China. RESULTS: Translation was conducted by forward- and back-translation, followed by harmonization and expert review. Two minor modifications were made during cognitive debriefing. Five hundred and nine respondents (54.4% males, aged 18-86 years) participated in the psychometric testing survey. The mean (standard deviation) duration of finishing SF-6Dv2 was 96.9 s (58.5 s). No respondents claimed difficulties on understanding/answering, and no ceiling/floor effect was found in the total summary score. Known-group validity verified that the questionnaire was able to distinguish between subgroups in terms of whether having chronic conditions. CONCLUSIONS: The Simplified Chinese version of SF-6Dv2 is demonstrated to be conceptually equivalent with the original English version, which is also understandable and easy to finish among the Chinese general population.

U.K. utility weights for the EORTC QLU-C10D.

The EORTC QLU-C10D is a new multi-attribute utility instrument derived from the widely used cancer-specific quality of life questionnaire, EORTC QLQ-C30. It contains 10 dimensions (physical functioning, role functioning, social functioning, emotional functioning, pain, fatigue, sleep, appetite, nausea, bowel problems), each with four levels. The aim of this study was to provide U.K. general population utility weights for the QLU-C10D. A U.K. online panel was quota-sampled to align the sample to the general population proportions of sex and age (≥18 years). The online valuation survey included a discrete choice experiment (DCE). Each participant was asked to complete 16 choice-pairs, each comprising two QLU-C10D health states plus duration. DCE data were analysed using conditional logistic regression to generate utility weights. Data from 2,187 respondents who completed at least one choice set were included in the DCE analysis. The final U.K. QLU-C10D utility weights comprised decrements for each level of each health dimension. For nine of the 10 dimensions (all except appetite), the expected monotonic pattern was observed across levels: Utility decreased as severity increased. For the final model, consistent monotonicity was achieved by merging inconsistent adjacent levels for appetite. The largest utility decrements were associated with physical functioning and pain. The worst possible health state (the worst level of each dimension) is -0.083, which is considered slightly worse than being dead. The U.K.-specific utility weights will enable cost-utility analysis (CUA) for the economic evaluation of new oncology therapies and technologies in the United Kingdom, where CUA is commonly used to inform resource allocation.

Consistency Between Three Different Ways of Administering the Short Form 6 Dimension Version 2.

BACKGROUND: The Short Form 6 Dimension (SF-6D) is a multi-attribute utility instrument derived from the Short-Form 36 Health Survey Version 2 (SF-36v2) quality of life questionnaire and is used to calculate quality-adjusted life years (QALYs) on a scale 0 to 1. The SF-6Dv2 is a new version of the SF-6D. OBJECTIVE: The aim of this study was to assess the consistency of respondents' answers to 3 different methods to administer this new version. METHODS: SF-6Dv2 utility values were generated from the SF-36v2 using the following: (1) full questionnaire with 36 items (SF-6Dv2SF-36); (2) subset questionnaire with 10 items (SF-6Dv2ind-10); (3) SF-6Dv2 administered as an independent instrument (rephrased questionnaire with only 6 items [SF-6Dv2ind-6]). The order of the 3 instruments was randomly allocated between respondents. RESULTS: A total of 782 respondents from Quebec, Canada, were interviewed, out of whom 697 fully completed the survey. Very few deviations in respondents' answers were observed between the 3 instruments, with mean weighted kappa of 0.79 (range 0.61-0.91) and mean global consistency index of 70% (range 54-83). Maximal difference in utility values generated was found between SF-6Dv2ind-10 and SF-6Dv2ind-6 (mean difference 0.016, P < .01), whereas minimal difference was found between SF-6Dv2SF-36 and SF-6Dv2ind-10 (0.002, P = .38). No ceiling effect was observed. CONCLUSIONS: The SF-6Dv2 was designed to derive utilities from the SF-36v2, and our results indicate that it is still preferable to use the full questionnaire, although the difference with other variants of the questionnaire is very small. To use the SF-6Dv2 as an independent instrument will thus introduce minimal bias in utility values generated.

Developing a preference-based utility scoring algorithm for the Psoriasis Area Severity Index (PASI).

Introduction: It is challenging to identify health state utilities associated with psoriasis because generic preference-based measures may not capture the impact of dermatological symptoms. The Psoriasis Area Severity Index (PASI) is one of the most commonly used psoriasis rating scales in clinical trials. The purpose of this study was to develop a utility scoring algorithm for the PASI. Methods: Forty health states were developed based on PASI scores of 40 clinical trial patients. Health states were valued in time trade-off interviews with UK general population participants. Regression models were conducted to crosswalk from PASI scores to utilities (e.g. OLS linear, random effects, mean, robust, spline, quadratic). Results: A total of 245 participants completed utility interviews (51.4% female; mean age = 45.3 years). Models predicting utility based on the four PASI location scores (head, upper limbs, trunk, lower limbs) had better fit/accuracy (e.g. R2, mean absolute error [MAE]) than models using the PASI total score. Head/upper limb scores were more strongly associated with utility than trunk/lower limb. The recommended model is the OLS linear model based on the four PASI location scores (R2 = 0.13; MAE = 0.03). An alternative is recommended for situations when it is necessary to estimate utility based on the PASI total score. Conclusions: The derived scoring algorithm may be used to estimate utilities based on PASI scores of any treatment group with psoriasis. Because the PASI is commonly used in psoriasis clinical trials, this scoring algorithm greatly expands options for quantifying treatment outcomes in cost-effectiveness analyses of psoriasis therapies. Results indicate that psoriasis of the head/upper limbs could be more important than trunk/lower limbs, suggesting reconsideration of the standard PASI scoring approach.