A direct comparison between discrete choice with duration and composite time trade-off methods: do they produce similar results?

OBJECTIVES: Discrete Choice Experiments (DCE) including a duration attribute (DCEd) represent a promising candidate method for valuing health-related quality-of-life instruments. However, it has not been established that DCEd can produce similar results as composite Time-Trade-Off (cTTO) or EuroQol Valuation Technology (EQ-VT) valuations of the EQ-5D-5L instrument. This study provides a direct comparison between cTTO and EQ-VT, and DCEd valuation methods. METHODS: An EQ-VT study was conducted in Trinidad and Tobago to value the EQ-5D-5L. 1079 respondents each completed 10 cTTO tasks and 12 DCE tasks without a duration attribute. A separate sample of 970 respondents each completed 18 split-triplet DCEd tasks. Several regression models were applied to the EQ-VT data, and the DCEd data were analysed using mixed logit models with an exponential discount rate. The estimated values were compared using scatterplots and Bland-Altman plots. RESULTS: The ordering of dimensions was identical in level 5 for cTTO/EQ-VT and DCEd models, with pain/discomfort being the most important dimension and usual activities being least important. cTTO/EQ-VT models produced a value for state 55555 ranging between -0.52 and -0.69, while this was -0.543 for the non-linear mixed logit model for the DCEd data. Scatterplots and Bland-Altman plots suggested excellent agreement between cTTO/EQ-VT and DCEd-based estimates. CONCLUSIONS: CTTO/EQ-VT and DCEd valuations produce similar results when correcting DCEd for non-linear time preferences. The ordering of importance of the dimensions and scale are identical, suggesting that the two methods measure the same construct and produce similar results.

Valuation of EQ-5D-5L in the Kingdom of Saudi Arabia: A National Representative Study.

OBJECTIVES: To estimate a Saudi-specific value set for the EQ-5D-5L questionnaire using the EuroQol Valuation Technology program and the EuroQol Group's standard protocol. METHODS: Participants were quota-sampled from the Saudi adult population based on residency location, age group, gender, education level, and employment status. The participants were guided through the completion of composite time trade-off (cTTO) and discrete choice experiment (DCE) tasks by trained interviewers using EuroQol Valuation Technology software. Quality control (QC) measures were used to ensure good data quality. Random intercept and Tobit models analyzed the cTTO data, as well as models correcting for heteroskedasticity. DCE data were analyzed using conditional logit models, whereas hybrid models were used to analyze the cTTO and DCE data jointly. To evaluate model performance, prediction accuracy, logical consistency, significance level, and goodness of fit were used. RESULTS: The valuation study included a representative sample of the Saudi population (N = 1000). The hybrid heteroskedastic model without a constant was chosen as the preferred model for generating the value set. The predicted values ranged from -0.683 for the worst health state ("55555") to 1 for the full health state ("11111"). Pain and discomfort had the largest impact on health-state preference values, whereas usual activities had the least. CONCLUSION: The value set for the Kingdom of Saudi Arabia is the first value set for the EQ-5D-5L for any country in the Middle East. The value set can be used in Saudi health system economic evaluations and decision making.

The EQ-5D-5L valuation study for Trinidad and Tobago.

PURPOSE: The 2016 EQ-5D-3L value set for Trinidad and Tobago (T&T) allows for the calculation of EQ-5D-5L values via the crosswalk algorithm. The 2016 value set was based on methods predating the EQ-VT protocol, now considered the gold standard for developing EQ-5D value sets. Furthermore, direct elicitation of EQ-5D-5L is preferred over crosswalked values. This study aimed to produce an EQ-5D-5L value set for T&T. METHODS: A representative sample (age, sex, geography) of adults each completed 10 composite Time Trade-Off (cTTO) tasks and 12 Discrete Choice Experiment (DCE) tasks in face-to-face interviews. The cTTO data were analyzed using a Tobit model that corrects for heteroskedasticity. DCE data were analyzed using a mixed logit model. The cTTO and DCE data were combined in hybrid models. RESULTS: One thousand and seventy-nine adults completed the valuation interviews. Among the modelling approaches that were explored, the hybrid heteroskedastic Tobit model produced all internally consistent, statistically significant coefficients, and performed best in terms of out-of-sample predictivity for single states. Compared to the existing EQ-5D-5L crosswalk set, the new value set had a higher number of negative values (236 or 7.6% versus 21 or 0.7%). The mean absolute difference was 0.157 and the correlation coefficient between the two sets was 0.879. CONCLUSION: This study provides a value set for the EQ-5D-5L for T&T using the EQ-VT protocol. We recommend this value set for QALY computations relating to T&T.

Modifying the Composite Time Trade-Off Method to Improve Its Discriminatory Power.

OBJECTIVES: In cost-effectiveness analysis of health technologies, health state utilities are needed. They are often elicited with a composite time trade-off (cTTO) method, particularly for the widely used EQ-5D-5L. Unfortunately, cTTO discriminatory power is hindered by (1) respondents' nontrading (NT) of time for quality, (2) censoring of utilities at -1, and (3) poor correlation of negative utilities with state severity. We investigated whether modifying cTTO can mitigate these effects. METHODS: We interviewed online 478 students (February to April, 2021) who each valued the same 10 EQ-5D-5L health states in 1 of 3 arms. Arm A used a standard cTTO, expanded with 2 questions to explore reasons for NT and censoring. Arms B and C used a time trade-off with modified alternatives offered to overcome loss aversion, to unify the tasks for positive and negative utilities, and to enable eliciting utilities < -1. RESULTS: In arms B and C, we observed less NT than in A (respectively, 4% and 4% vs 10%), more strictly negative utilities (38% and 40% vs 25%), and more utilities ≤ -1 (18% and 30% vs 10%). The average utility of state 55555 dropped to -2.15 and -2.52 from -0.53. Enabling finer trades in arm A reduced NT by 70%. Arms B and C yielded an intuitive association between negative utilities and state severity. These arms were considered more difficult and resulted in more inconsistencies. CONCLUSIONS: The discriminatory power of cTTO can be improved, but it may require increasing the difficulty of the task. The standard cTTO may overestimate the utilities, especially of severe states.

The Sensitivity and Specificity of Repeated and Dominant Choice Tasks in Discrete Choice Experiments.

OBJECTIVES: This study aimed to identify the most commonly used internal validity tests in the discrete choice experiment (DCE) literature and establish their sensitivity and specificity. METHODS: A structured literature review of recent DCE articles (2018-2020Q1) published in the health, marketing, transport economics, and environmental science literature was used to identify commonly used internal validity tests. The 2 most frequently used internal validity tests were incorporated in 4 new data collections. Respondent preferences in each application were summarized using a mixed logit model, which served as the benchmark for the subsequent sensitivity and specificity calculations. The performance of the internal validity tests was also compared with that of the root likelihood (RLH) test, which is a likelihood-based statistical validity test that is commonly used in marketing applications. RESULTS: Dominant and repeated choice tasks were most commonly included in health-related DCE designs. Based on 4 applications, their specificity and sensitivity depend on the type of incorrect response pattern to be detected and on design characteristics such as the number of choice options per choice task and the number of internal validity tests as included in the experimental design. In all but one scenario, the performance of the dominant and repeated choice tasks was considerably worse than that of the RLH test. CONCLUSIONS: Dominant and repeated choice tasks are unreliable screening tests and costly in terms of statistical power. The RLH test, which is a statistical test that does not require additional choice tasks to be included in the DCE design, provides a more reliable alternative.

A threshold explanation for the lack of variation in negative composite time trade-off values.

BACKGROUND: Recent studies concluded that for health states considered worse than dead (WTD), as measured with the time trade-off (cTTO) method, negative mean values were insensitive to health state severity, which represents a validity problem for the cTTO. However, the aforementioned studies analysed negative values in isolation, which causes selection bias as the value distribution is truncated. AIM: To investigate the validity of aforementioned studies and of negative values in general. METHODS: The 'threshold explanation' was formulated: beyond a certain severity threshold, preferences change from better than dead (BTD) to WTD. This threshold differs between respondents. Thus, negative values across severity are obtained from different respondents, and responses added for higher severity contribute negative values close to zero, explaining the aforementioned insensitivity. This explanation was tested using data from the Dutch EQ-5D-5L valuation study. Respondents valued 10 health states. Based on respondents' number of WTD preferences, segments were constructed, containing respondents with similar severity thresholds. Using regression models for each individual respondent, we examined the relation between values and severity and compared respondents between segments. RESULTS: Negative values, when analysed in isolation, were insensitive to severity. However, for individual respondents and within most segments, cTTO values and severity were negatively related. For individual respondents, negative slopes were steeper for segments with more WTD preferences, as predicted by the threshold explanation. DISCUSSION: Analysing negative values in isolation leads to biased estimates. Analyses of cTTO values for individual respondents refute the insensitivity of negative cTTO values.

Valuation of the EQ-5D-3L in Russia.

PURPOSE: The most widely used generic questionnaire to estimate the quality of life for yielding quality-adjusted life years in economic evaluations is EQ-5D. Country-specific population value sets are required to use EQ-5D in economic evaluations. The aim of this study was to establish an EQ-5D-3L value set for Russia. METHODS: A representative sample aged 18+ years was recruited from the Russia`s general population. Computer-assisted face-to-face interviews were conducted based on the standardized valuation protocol using EQ-Portable Valuation Technology. Population preferences were elicited utilizing both composite time trade-off (cTTO) and discrete choice experiment (DCE) techniques. To estimate the value set, a hybrid regression model combining cTTO and DCE data was used. RESULTS: A total of 300 respondents who successfully completed the interview were included in the primary analysis. 120 (40.0%) respondents reported no health problems of any dimension, and 56 (18.7%) reported moderate health problems in one dimension of the EQ-5D-3L. Median self-rated health using EQ-VAS was 80 with IQR 70-90. Comparing cTTO and DCE-predicted values for 243 health states resulted in a similar pattern. This supports the use of hybrid models. The predicted value based on the preferred model for the worst health state "33333" was -0.503. Mobility dimension had the most significant impact on the utility decrement, and anxiety/depression had the lowest decrement. CONCLUSION: Determining a Russian national value set may be considered the first step towards promoting cost-utility analysis use to increase comparability among studies and improve the transferability of healthcare decision-making in Russia.

Valuing health-related quality of life using a hybrid approach: Tunisian value set for the EQ-5D-3L.

OBJECTIVE: To develop a value set for EQ-5D-3L based on the societal preferences of the Tunisian population. METHODS: A representative sample of the Tunisian general population was obtained through multistage quota sampling involving age, gender and region. Participants (n = 327), aged above 20 years, were interviewed using the EuroQol Portable Valuation Technology in face-to-face computer-assisted interviews. Participants completed 10 composite time trade-off (cTTO) and 10 discrete choice experiments (DCE) tasks. Utility values for the EQ-5D-3L health states were estimated using regression modeling. The cTTO and DCE data were analyzed using linear and conditional logistic regression modeling, respectively. Multiple hybrid models were computed to analyze the combined data and were compared on goodness of fit measured by the Akaike information criterion (AIC). RESULTS: A total of 300 participants with complete data that met quality criteria were included. All regression models showed both logical consistency and significance with respect to the parameter estimates. A hybrid model accounting for heteroscedasticity presented the lowest value for the AIC among the hybrid models. Hence, it was used to construct the Tunisian EQ-5D-3L valuation set with a range of predicted values from - 0.796 to 1.0. CONCLUSION: This study provides utility values for EQ-5D-3L health states for the Tunisian population. This value set will be used in economic evaluations of health technologies and for Tunisian health policy decision-making.

A Head-On Ordinal Comparison of the Composite Time Trade-Off and the Better-Than-Dead Method.

OBJECTIVES: The valuation of health states worse than dead is challenging. Currently used time trade-off methods face problems in (1) detecting time-dependent preferences and (2) insensitivity toward severity for states worse than dead. The better-than-dead (BTD) method has the potential to detect time-dependent preferences. This study compares the BTD and composite time trade-off (cTTO) methods at the ordinal level. METHODS: An experiment was conducted in a convenience sample in which respondents (N = 200) valued the same set of 7 health states in the BTD method and cTTO method. Binary BTD responses were used, with response categories of better than dead and worse than dead. Ternary cTTO responses were used, with the additional equal-to-dead response category. Polychoric correlations were used to determine the agreement between these methods. Consistency and test-retest reliability were assessed within methods. RESULTS: Overall agreement between the cTTO and BTD method equaled 77.1% and differed between health states and respondents. For both methods, there were few inconsistencies, and the test-retest reliability was comparable (88%). Health states were more often considered worse than dead in the BTD method (BTD: 54.7%, cTTO: 37.2%). CONCLUSIONS: The high agreement between both methods and the comparable amount of inconsistencies and test-retest reliability suggest that the methods have similar measurement properties. The BTD method yielded higher frequencies of worse-than-dead responses while essentially asking respondents to make similar choices. This accounts for part of the disagreement between the methods. Several explanations are offered for this difference, yet more research is needed to explain this phenomenon.

Cultural values: can they explain self-reported health?

PURPOSE: Self-reported health (SRH) is a measure widely used in health research and population studies. Differences in SRH have been observed between countries and cultural values have been hypothesized to partly explain such differences. Cultural values can be operationalized by two cultural dimensions using the World Values Survey (WVS), namely the traditional/rational-secular and the survival/self-expression dimension. We investigate whether there is an association between the WVS cultural dimensions and SRH, both within and between countries. METHODS: Data from 51 countries in the WVS is used and combined with macroeconomic data from the Worldbank database. The association between SRH and the WVS cultural dimensions is tested within each of the 51 countries and multilevel mixed models are used to test differences between these countries. Socio-demographic and macroeconomic variables are used to correct for non-cultural variables related to SRH. RESULTS: Within countries, the survival/self-expression dimension was positively associated with SRH, while in most countries there was a negative association for the traditional/rational-secular dimension. Values range between 4 and 17% within countries. Further analyses show that the associations within countries and between countries are similar. Controlling for macroeconomic and socio-demographic factors did not change our results. DISCUSSION: The WVS cultural dimensions predict SRH within and between countries. Contrary to our expectations, traditional/rational-secular values were negatively associated with SRH. As SRH is associated with cultural values between countries, cultural values could be considered when interpreting SRH between countries.

Prognostic Information on Progression to Dementia: Quantification of the Impact on Quality of Life.

Background: The increasing interest in early identification of people at risk of developing dementia, has led to the development of numerous models aimed at estimating the likelihood of progression from mild cognitive impairment (MCI) to dementia. It is important to study both the need for and possible outcomes related with such prediction models, including the impact of risk predictions on perceived quality of life (QoL). Objective: This study aimed to quantify the impact that receiving a risk prediction on progression from MCI to dementia has on QoL. Methods: A Discrete Choice Experiment (DCE) and Time Trade Off (TTO) study were performed. Participants completed choice tasks related to dementia prognosis while imagining having MCI. We collected DCE data by an online survey, and TTO data via videoconferencing interviews. DCE data were analyzed using a mixed multinomial logit model and were anchored to a health state utility scale using mean observed TTO valuations. Results: 296 people participated in the DCE and 42 in the TTO. Moderate and high predicted dementia risks were associated with decrements in utility (-0.05 and -0.18 respectively), compared to no prognostic information. Low predicted risk was associated with an increase in utility (0.06), as well as the availability of medication or lifestyle interventions (0.05 and 0.13 respectively). Conclusions: This study shows a significant impact of dementia risk predictions on QoL and highlights the importance of caution when sharing information about expected MCI disease courses.

Estimating an EQ-5D-Y-3L Value Set for Brazil.

INTRODUCTION: The EQ-5D-Y-3L is a generic measure of health-related quality of life in children and adolescents. Although the Brazilian-Portuguese EQ-5D-Y-3L version is available, there is no value set for it, hampering its use in economic evaluations. This study aimed to elicit a Brazilian EQ-5D-Y-3L value set based on preferences of the general adult population. METHODS: Two independent samples of adults participated in an online discrete choice experiment (DCE) survey and a composite time trade-off (cTTO) face-to-face interview. The framing was "considering your views for a 10-year-old child". DCE data were analyzed using a mixed-logit model. The 243 DCE predicted values were mapped into the observed 28 cTTO values using linear and non-linear mapping approaches with and without intercept. Mapping approaches' performance was assessed to estimate the most valid method to rescale DCE predicted values using the model fit (R2), Akaike Information Criteria (AIC), root mean squared error (RMSE), and mean absolute error (MAE). RESULTS: A representative sample of 1376 Brazilian adults participated (DCE, 1152; cTTO, 211). The linear mapping without intercept (R2 = 96%; AIC, - 44; RMSE, 0.0803; MAE, - 0.0479) outperformed the non-linear without intercept (R2 = 98%; AIC, - 63; RMSE, 0.1385; MAE, - 0.1320). Utilities ranged from 1 (full health) to - 0.0059 (the worst health state). Highest weights were assigned to having pain or discomfort (pain/discomfort), followed by walking about (mobility), looking after myself (self-care), doing usual activities (usual activities), and feeling worried, sad, or unhappy (anxiety/depression). CONCLUSION: This study elicited the Brazilian EQ-5D-Y-3L value set using a mixed-logit DCE model with a power parameter based on a linear mapping without intercept, which can be used to estimate the quality-adjusted life-years for economic evaluations of health technologies targeting the Brazilian youth population.

The EQ-5D-3L Valuation Study in Pakistan.

BACKGROUND: To utilize EQ-5D in economic evaluations, a societal-based value set is needed. To date, no value sets exist for any EQ-5D instrument in Pakistan. Previous EQ-5D studies conducted in Pakistan 'borrowed' health preferences developed in other countries. However, for a value set to be valid for Pakistani population, it should represent the preferences of the Pakistani population, and culture and living standards of Pakistan. OBJECTIVE: The aim of this study was to derive a Pakistani EQ-5D-3L value set. METHODS: A moderately representative sample aged 18 years and over was recruited from the Pakistani general population. A multi-stage stratified quota method with respect to ethnicity, gender, age and religion was utilized. Two elicitation techniques, the composite time trade-off (cTTO) and discrete choice experiments (DCE) were applied. Interviews were undertaken by trained interviewers using computer-assisted face-to-face interviews with the EuroQol Portable Valuation Technology (EQ-PVT) platform. To estimate the value set, a hybrid regression model combining cTTO and DCE data was used. RESULTS: A total of 289 respondents who completed the interviews were included for the analysis. The hybrid model correcting for heteroskedasticity without a constant was selected as the final model for the value set. It is shown that being unable to do usual activities (level 3) was assigned the largest weight, followed by mobility level 3, self-care level 3, pain/discomfort level 3 and anxiety/depression level 3. The worst health state was assigned the value - 0.171 in the final model. CONCLUSIONS: A Pakistani country-specific EQ-5D-3L value set is now available. The availability of this value set may help promote and facilitate health economic evaluations and health-related quality-of-life (HRQoL) research in Pakistan.

The Egyptian EQ-5D-5L Extensive Pilot Study: Lessons Learned.

OBJECTIVES: To investigate the effect of an extensive pilot phase in improving protocol compliance, face validity, reduction of interviewer effect and prediction errors in the composite time trade-off (cTTO) data elicited as part of the EQ-5D-5L valuation study in Egypt. METHODS: This study used the cTTO data and quality control (QC) reports from the Egyptian EQ-5D-5L valuation study. Three-level mixed models were estimated to test whether interviewer effects were reduced during the pilot phase and subsequent rounds of collected cTTO data. Ordinary least square (OLS) regression analysis was conducted for each interviewer separately to test whether the mean absolute error (MAE) improved as interviewers completed more interviews. Moreover, improvement in protocol compliance, face validity and reduction of prediction errors in the cTTO data were tested. RESULTS: 1180 interviews were conducted by nine interviewers and included in the final analysis, of which 206 interviews were pilot and 974 interviews were actual. There was substantial improvement in the face validity and reduction of prediction errors in the cTTO data where the MAE of the actual data was 0.37, which is much lower than that of the pilot data, which was 0.44. However, there was an initial high level of protocol compliance in terms of the four indicators of the QC tool and the variance attributed to the interviewers was small throughout the whole study. CONCLUSIONS: This study clarified the benefits of the pilot phase and the strict implementation of the QC tool in improving the face validity and the prediction accuracy of the cTTO data. However, a more extensive pilot phase may be more beneficial in EQ-5D-5L valuation studies that have issues initially with protocol compliance and interviewer effects.

An EQ-5D-5L value set for Italy using videoconferencing interviews and feasibility of a new mode of administration.

OBJECTIVES: To test the feasibility of using videoconferencing (VC) administered interviews and to derive an EQ-5D-5L value set for Italy. METHODS: Preferences were collected using the EuroQol standardized valuation protocol (EQ-VT) administered via VC. Two valuation methods were employed, composite time trade-off (cTTO) and discrete choice experiment (DCE). Technical, organizational and protocol feasibility were tested in a pilot of 198 interviews. Upon positive assessment, data collection continued with a target sample of 1000-1200 participants including the pilot. Quality control (QC) procedures were employed to monitor interviewers' performance during the pilot and the data collection. Data were modelled using GLS, Tobit, Logit and Hybrid models with different error specifications. Monotonicity of coefficients, statistical significance, and theoretical considerations informed the model choice. RESULTS: Dropouts and technical problems occurred in less than 5% of the 198 pilot interviews. Protocol compliance was demonstrated with significant improvements in QC parameters and limited interviewers' effects, for all interviewers. Overall, interviewers were satisfied with this mode of administration, highlighting it allows flexibility and efficient scheduling. Based on these results, VC was deemed as a feasible mode of administration. The study collected preferences for 1182 responders, including the pilot interviews. The demographic characteristics of the sample were representative of the Italian general population for age, gender and geographical macro-areas. The hybrid Tobit heteroscedastic model without constant estimated on the full sample (including pilot) was selected for the derivation of the value set. Values ranged from -0.571 for the worst health state (55555) to 1 for the best health state (11111). Pain/discomfort registered the largest decrement, followed by mobility, anxiety/depression, self-care, and usual activities. 523 health states were worse than dead. CONCLUSIONS: VC is viable for the conduct of valuation interviews. The Italian value set for the EQ-5D-5L can be used for value determinations of health technologies.

An EQ-5D-Y-3L Value Set for Belgium.

BACKGROUND: In Belgium, a value set for children and adolescents for a generic health-related quality-of-life measure is not available. To inform drug pricing and make resource allocation decisions for children and adolescents, national tax-payers' preferences for youth health states should be known. OBJECTIVE: We aimed to obtain a value set for EQ-5D-Y-3L in Belgium, following the international youth valuation protocol for data collection. METHODS: Composite Time Trade-Off interviews were conducted in a sample of 200 adults, either face to face or via video conferencing. Another sample of 1000 adults completed an online discrete choice experiment survey. All adults were asked to take the perspective of a 10-year-old child for both methods. Both samples were representative for Belgium in terms of age, sex and region. A latent class analysis was selected to obtain the relative importance of the five dimensions and their levels based on the discrete choice experiment data, which were anchored with the composite Time Trade-Off censored value for the worst health state (33333). RESULTS: Preferences from Belgian adults revealed a mean censored value for 33333 for children and adolescents of - 0.475. All the estimated coefficients of the model with 4 latent classes were statistically significant and showed higher disutility as severity levels increase. The most important health dimension was pain/discomfort, followed by feeling sad/worried/unhappy. CONCLUSIONS: This study presents the Belgian EQ-5D-Y-3L value set, which will be included in the Belgian pharmacoeconomic guidelines. The value set enables the calculation of quality-adjusted life-years in children and adolescents, allowing a cost-effectiveness evaluation of health technologies and their youth-specific price setting.

Estimating an EQ-5D-Y-3L Value Set for Indonesia by Mapping the DCE onto TTO Values.

BACKGROUND AND OBJECTIVES: Methods for estimating health values in adult populations are well developed, but lag behind in children. The EuroQol standard protocol to arrive at value sets for the youth version of the EQ-5D-Y-3L combines discrete choice experiments with ten composite time trade-off values. Whether ten composite time trade-off values are sufficient remains to be seen and this is one of the reasons the protocol allows for experimental expansion. In this study, 23 health states were administered for the composite time trade-off. This methodological research is embedded in a study aimed at generating a representative value set for EQ-5D-Y-3L in Indonesia. METHODS: A representative sample of 1072 Indonesian adults each completed 15 discrete choice experiment choice pairs via face-to-face interviews. The discrete choice experiment responses were analysed using a mixed-logit model. To anchor the discrete choice experiment values onto the full health-dead quality-adjusted life-year scale, composite time trade-off values were separately obtained from 222 adults living in Java for 23 EQ-5D-Y-3L states. The derived latent discrete choice experiment values were mapped onto the mean observed composite time trade-off values to create a value set for the EQ-5D-Y-3L. Linear and non-linear mapping models were explored to estimate the most efficient and valid model for the value set. RESULTS: Coefficients obtained from the choice model were consistent with the monotonic structure of the EQ-5D-Y-3L instrument. The composite time trade-off data showed non-linearity, as the values for the two worst states being evaluated were much lower than predicted by a standard linear model estimated over all composite time trade-off data. Thus, the non-linear mapping strategies with a power term outperformed the linear mapping in terms of mean absolute error. The final model gave a value range from 1.000 for full health (11111) to - 0.086 for the worst health state (33333). Values were most affected by pain/discomfort and least by self-care. CONCLUSIONS: This article presents the first EQ-5D-Y-3L value set for Indonesia based on the stated preferences of adults asked to consider their views about a 10-year-old child. Mapping the mixed-logit discrete choice experiment model with the inclusion of a power term (without a constant) allowed us to generate a consistent value set for Indonesian youth. Our findings support the expansion of the composite time trade-off part of the EQ-5D-Y valuation study design and show that it would be wise to account for possible non-linearities in updates of the design.

A Value Set for the EQ-5D-Y-3L in the Netherlands.

BACKGROUND AND OBJECTIVE: There is increasing interest in preference-accompanied measures of health for paediatric populations. The child-friendly EQ-5D version, EQ-5D-Y-3L, is one such instrument, but the lack of a Dutch value set prevents its use in economic evaluations of healthcare interventions in the Netherlands. This study aims at covering this gap by collecting preferences using a standardised protocol for deriving EQ-5D-Y-3L value sets. METHODS: Composite time trade-off data were collected using videoconferencing interviews, with each respondent completing ten composite time trade-off tasks. Discrete choice experiment data were collected using an online survey, with respondents each completing 15 paired comparisons. Respondents completed these tasks considering what they prefer for a hypothetical 10-year-old child. Discrete choice experiment data were analysed using a ten-parameter mixed-logit model and anchored to the quality-adjusted life-year scale using the mean observed composite time trade-off values. RESULTS: The study collected preferences for 197 respondents using composite time trade-off and for 959 respondents using a discrete choice experiment. The discrete choice experiment sample was representative for the Dutch population in terms of age and sex. The level 3 weight for pain/discomfort was the largest, followed by feeling worried, sad or unhappy, usual activities, mobility and self-care. Health state values ranged between -0.218 and 1. CONCLUSIONS: This study generated a Dutch value set for the EQ-5D-Y-3L, which can be used for the computation of quality-adjusted life-years for economic evaluations of healthcare interventions in paediatric populations.

The EQ-5D-5L Valuation Study in Egypt.

INTRODUCTION: No value sets exist for either the EQ-5D-3L or the EQ-5D-5L in Egypt, despite local pharmacoeconomic guidelines recommending the use of the EQ-5D to derive utility. Most published Egyptian economic evaluation studies have used utility values from other published studies and systematic reviews. OBJECTIVE: Our objective was to develop an Egyptian EQ-5D-5L value set using the international EuroQol standardized protocol (EQ-VT-2.1). This study is a revision of a previous EQ-5D-5L value set for Egypt retracted by the authors. METHODS: Adult Egyptian participants were recruited from public places using multi-stratified quota sampling based on age, sex, and geographical distribution. Two elicitation techniques were applied: the composite time trade-off (cTTO) and discrete-choice experiments (DCEs). Before actual data collection, interviewers' performance was assessed in a pilot phase. Data were modelled using generalized least squares, Tobit, heteroskedastic, logit, and hybrid models, and the best fitting model was selected based on logical consistency of the parameters, significance level, prediction accuracy, and model parsimony. RESULTS: A total of 1378 interviews were conducted, of which 188 were excluded because they were incomplete and did not comply with the protocol, 216 were pilot interviews, and 974 were included in the final analysis. The heteroskedastic model with constraints (model 4) based on the cTTO data was selected as the preferred model to generate the value set. Values ranged from - 0.964 for the worst health state (55555) to 1 for full health (11111) and 0.948 for 11211, with 1123 of all predicted health states (35.94%) being worse than dead. Mobility had the largest impact on health state preference values. CONCLUSION: This is the first value set for the EQ-5D-5L based on social preferences obtained from a nationally representative sample in Egypt or any Arabic-speaking country. The value set can be used as a scoring system for economic evaluation and to improve the quality of health technology assessment in the Egyptian healthcare system.

In a Child's Shoes: Composite Time Trade-Off Valuations for EQ-5D-Y-3L with Different Proxy Perspectives.

BACKGROUND AND OBJECTIVES: EQ-5D-Y-3L health states are commonly valued by asking adults to complete stated preference tasks, 'given their views about a 10-year-old child' (hereafter referred to as proxy 1). The use of this perspective has been a source of debate. In this paper, we investigated an alternative proxy perspective: i.e. adults considered what they think a 10-year old-child would decide for itself (hereafter, proxy 2 (substitute)]. Our main objective was to explore how the outcomes, dispersion and response patterns of a composite time trade-off valuation differ between proxy 1 and proxy 2. METHODS: A team of four trained interviewers completed 402 composite time trade-off interviews following the EQ-5D-Y-3L protocol. Respondents were randomly allocated to value health states in either the proxy 1 or proxy 2 (substitute) perspective. Each respondent valued ten health states with the perspective they were assigned to, as well as one health state with the alternative perspective (33333). RESULTS: The use of different proxy perspectives yielded differences in EQ-5D-Y-3L valuation. For states in which children had considerable pain and were very worried, sad or unhappy, respondents' valuations were lower in proxy 1 than in proxy 2 (substitute) perspectives, by about 0.2. Within-subject variation across health states was lower for proxy 2 (substitute) than proxy 1 perspectives. Analyses of response patterns suggest that data for proxy 2 (substitute) perspectives were less clustered. CONCLUSIONS: There are systematic differences between composite time trade-off responses given by adults deciding for children and adults considering what children would want for themselves. In addition to warranting further qualitative exploration, such differences contribute to the ongoing normative discussion surrounding the source and perspective used for valuation of child and adolescent health.