One-to-one versus group setting for conducting computer-assisted TTO studies: findings from pilot studies in England and the Netherlands

A Methodological Study to Compare Alternative Modes of Administration with Value EQ-5D Using Preference-Elicitation Techniques

OBJECTIVES

Time trade-off (TTO) and discrete choice experiment (DCE) preference-elicitation techniques can be administered using face-to-face interviews (F2F), unassisted online (UO) surveys, or remote-assisted (RA) interviews. The objective of this study was to explore how the mode of administration affects the quality and reliability of preference-elicitation data.

METHODS

EQ-5D-5L health states were valued using composite TTO (cTTO) and DCE approaches by the UK general population. Participants were allocated to 1 of 2 study groups. Group A completed both F2F and UO surveys (n = 271), and group B completed both RA and UO surveys (n = 223). The feasibility of survey completion and the reliability and face-validity of data collected were compared across all modes of administration.

RESULTS

Fewer participants reported receiving sufficient guidance on the cTTO tasks during the UO survey compared with the 2 assisted modes. Participants across all modes typically reported receiving sufficient guidance on the DCE tasks. cTTO data were less reliable from the UO survey compared with both assisted modes, but there were no differences in DCE data reliability. cTTO data from all modes demonstrated face-validity; however, the UO survey produced higher utilities for moderate and severe health states than both assisted modes. Both F2F and RA modes provided comparably reliable data.

CONCLUSIONS

The reliability of DCE data is not affected by the mode of administration. Interviewer-assisted modes of administration (F2F or RA) yield more reliable cTTO data than unassisted surveys. Both F2F and RA surveys produced similar-quality data.

Randomised comparison of online interviews versus face-to-face interviews to value health states

INTRODUCTION

Health state valuation studies using composite time trade-off (cTTO) interviews have historically been conducted face-to-face. The COVID-19 pandemic forced disruptive innovation meaning a number of valuation studies conducted interviews via videoconference. These studies found online interviews feasible and acceptable; however, studies were not constructed to test the impact of online versus face-to-face interviews. This study builds on its sister study from the UK and aims to assess the acceptability and equivalence of in person face-to-face interviews with online interviews on cTTO valuation outcomes and on data quality.

METHODS

Participants were recruited into a randomised equivalence study via an external research company. Consenting participants were randomly allocated to complete a cTTO interview face-to-face or online, using the same 10 EQ-5D-5L health states. Mean and distribution of the cTTO values, participant understanding, data quality, demographic characteristics, participant preference, participant engagement and participant feedback were all compared across interview mode. Statistical equivalence for cTTO values for each state was tested using two one-sided t-tests by mode. Finally, regression analysis was completed to assess the impacts of interview mode on cTTO value while controlling for demographic characteristics of the participants.

RESULTS

Mean cTTO values were shown to be equivalent for mild health states and showed no significant difference for serious health states. The proportion of individuals who expressed an interest in the study but declined to arrange an interview after finding out their randomisation was significantly higher for the face-to-face (21.6%) than the online group (1.8%). No significant difference was found between groups for participant engagement, understanding or feedback nor for any indicators of data quality.

CONCLUSION

Administrating interviews face to face or online did not appear to have a statistically significant impact on mean cTTO values. Offering both online and face-to-face interviews routinely allows all participants to select the most convenient option.

An EQ-5D-5L Value Set for Belgium

OBJECTIVE

This study aimed to establish a Belgian EQ-5D-5L value set based on the preferences of the adult Belgian general population.

METHODS

The most recent EuroQol Valuation Technology (EQ-VT 2.1) protocol for EQ-5D-5L valuation studies was followed. Computer-assisted personal interviews were carried out in a representative sample of the adult Belgian population. Potential respondents were randomly selected from the National Register using a multistage, stratified, cluster sampling with unequal probability design. Each respondent valued 10 or 11 health states using composite time trade-off (cTTO) and 14 health states in seven paired choice tasks using a discrete choice experiment (DCE). Different model specifications were explored and assessed based on logical consistency, goodness of fit, predictive accuracy and theoretical considerations.

RESULTS

A total of 892 respondents were included in the analyses. The sample was representative of the Belgian adult population in terms of age, sex, region of residence, educational attainment, labour market status, self-assessed health status and health-related quality of life (HRQoL). The preferred model specification was a hybrid (DCE and cTTO data combined) multiplicative eight-coefficient model with intercept random effects and correction for heteroskedasticity. Values range from - 0.532 to 1. Loss of HRQoL is highest in the dimension pain/discomfort, closely followed by anxiety/depression.

CONCLUSIONS

This study developed a Belgian EQ-5D-5L value set, based on the preferences of the Belgian adult general population. It provides opportunities for future clinical and economic evaluations in healthcare, for the measurement of patient-reported outcomes and for population health assessments.

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.

Time for Tele-TTO? Lessons Learned From Digital Interviewer-Assisted Time Trade-Off Data Collection

The preferred mode of administration of time trade-off (TTO) in large-scale valuation studies is face-to-face (personal) interviews facilitated by a trained interviewer. Geographical, financial or situational constraints could complicate personal TTO interviews. When facing such constraints, the use of digital interviews, in which trained interviewers facilitate through videotelephony software (i.e. tele-TTO) may be considered. This paper aims to guide researchers in how to approach tele-TTO interviews and discusses their advantages and disadvantages. The main advantages of tele-TTO compared to personal TTO are decreased need for travel and increased flexibility of interview scheduling, which could reduce costs and may foster representative sampling. Possible disadvantages of tele-TTO are partial loss of visual cues, complications with building rapport and possible selection effects that result from differences in interview preparation. Furthermore, the paper reports on lessons learned from a project in which both personal TTO and tele-TTO interviews were conducted. The results of this project suggest that although they require a different recruitment and interview process, tele-TTO interviews are feasible and provide flexibility to the interviewer. Furthermore, tele-TTO interviews yield largely similar results. Future research should explore the role of possible selection effects and respondents' perspective on tele-TTO interviews.

An overview of the time trade-off method: concept, foundation, and the evaluation of distorting factors in putting a value on health

INTRODUCTION

Preference-based instruments measuring health status express the value of specific health states in a single number. One method used is time trade-off (TTO). Health-status values are key elements in calculating quality-adjusted life years (QALYs) and are pertinent for resource allocation. Since they are used in economic evaluations of healthcare, searching for a theoretical foundation of TTO in economics is justified.

AREA COVERED

This paper provides an overview of TTO, including its relation to economic theory, and discusses biases and distortions, compiled from recent and older research. Inconsistencies between TTO and random utility theory were detected; The TTO is confounded by time preferences and by respondents' life expectancies. TTO is cognitively challenging, therefore guidance during the interviews is needed, producing interview effects. TTO does not measure one thing at a time, nor are the values independent of other states that are being valued in the same task. That is, TTO does not exhibit theoretical measurement properties such as unidimensionality and the invariance principle.

EXPERT OPINION

We conclude that the TTO may be a pragmatic method of eliciting health state values, but the limitations in regard to measurement theory and practical elicitation problems makes it prone to inconsistencies and arbitrariness.

Cultural Values: Can They Explain Differences in Health Utilities between Countries?

Introduction. Health utilities are widely used in health care. The distributions of utilities differ between countries; some countries more often report worse than dead health states, while mild states are valued more or less the same. We hypothesize that cultural values explain these country-related utility differences. Research Question. What is the effect of sociodemographic background, methodological factors, and cultural values on differences in health utilities? Methods and Analyses. Time tradeoff data from 28 EQ-5D valuation studies were analyzed, together with their sociodemographic variables. The dependent variable was Δu, the utility difference between mild and severe states. Country-specific cultural variables were taken from the World Values Survey. Multilevel models were used to analyze the effect of sociodemographic background, methodology (3L v. 5L), and cultural values on Δu. Intraclass correlation (ICC) for country variation was used to assess the impact of the predicting variables on the variation between countries. Results. Substantial variation in Δu was found between countries. Adding cultural values did not reduce ICCs for country variation. Sociodemographic background variables were only weakly associated with Δu and did not affect the ICC. Δu was 0.118 smaller for EQ-5D-5L studies. Discussion. Δu varies between countries. These differences were not explained by national cultural values. In conclusion, despite correction for various variables, utility differences between countries remain substantial and unexplained. This justifies the use of country-specific value sets for instruments such as the EQ-5D.

A Computer-Assisted Personal Interview App in Research Electronic Data Capture for Administering Time Trade-off Surveys (REDCap): Development and Pretest

Background

The time trade-off (TTO) task is a method of eliciting health utility scores, which range from 0 (equivalent to death) to 1 (equivalent to perfect health). These scores numerically represent a person’s health-related quality of life. Software apps exist to administer the TTO task; however, most of these apps are poorly documented and unavailable to researchers.

Objective

To fill the void, we developed an online app to administer the TTO task for a research study that is examining general public proxy health-related quality of life estimates for persons with Alzheimer’s disease. This manuscript describes the development and pretest of the app.

Methods

We used Research Electronic Data Capture (REDCap) to build the TTO app. The app’s modular structure and REDCap’s object-oriented environment facilitated development. After the TTO app was built, we recruited a purposive sample of 11 members of the general public to pretest its functionality and ease of use.

Results

Feedback from the pretest group was positive. Minor modifications included clarity enhancements, such as rearranging some paragraph text into bullet points, labeling the app to delineate different question sections, and revising or deleting text. We also added a research question to enable the identification of respondents who know someone with Alzheimer’s disease.

Conclusions

We developed an online app to administer the TTO task. Other researchers may access and customize the app for their own research purposes.

Valuing health-related quality of life: An EQ-5D-5L value set for England

A new version of the EQ-5D, the EQ-5D-5L, is available. The aim of this study is to produce a value set to support use of EQ-5D-5L data in decision-making. The study design followed an international research protocol. Randomly selected members of the English general public completed 10 time trade-off and 7 discrete choice experiment tasks in face-to-face interviews. A 20-parameter hybrid model was used to combine time trade-off and discrete choice experiment data to generate values for the 3,125 EQ-5D-5L health states. Valuation data are available for 996 respondents. Face validity of the data has been demonstrated, with more severe health states generally given lower values. Problems with pain/discomfort and anxiety/depression received the greatest weight. Compared to the existing EQ-5D-3L value set, there are considerably fewer "worse than dead" states (5.1%, compared with over one third), and the minimum value is higher. Values range from -0.285 (extreme problems on all dimensions) to 0.950 (for health states 11211 and 21111). Results have important implications for users of the EQ-5D-5L both in England and internationally. Quality-adjusted life year gains from interventions seeking to improve very poor health may be smaller using this value set and may previously have been overestimated.

Valuing health-related quality of life: An EQ-5D-5L value set for England

A new version of the EQ-5D, the EQ-5D-5L, is available. The aim of this study is to produce a value set to support use of EQ-5D-5L data in decision-making. The study design followed an international research protocol. Randomly selected members of the English general public completed 10 time trade-off and 7 discrete choice experiment tasks in face-to-face interviews. A 20-parameter hybrid model was used to combine time trade-off and discrete choice experiment data to generate values for the 3,125 EQ-5D-5L health states. Valuation data are available for 996 respondents. Face validity of the data has been demonstrated, with more severe health states generally given lower values. Problems with pain/discomfort and anxiety/depression received the greatest weight. Compared to the existing EQ-5D-3L value set, there are considerably fewer "worse than dead" states (5.1%, compared with over one third), and the minimum value is higher. Values range from -0.285 (extreme problems on all dimensions) to 0.950 (for health states 11211 and 21111). Results have important implications for users of the EQ-5D-5L both in England and internationally. Quality-adjusted life year gains from interventions seeking to improve very poor health may be smaller using this value set and may previously have been overestimated.

A (Latent) Class of Their Own: Response Patterns in Trading Off Quantity and Quality of Life in Time Trade-Off Exercises

BACKGROUND

Conflicting results regarding associations of time trade-off (TTO) valuations with respondent characteristics have been reported, mostly on the basis of regression analyses. Alternative approaches, such as the latent class analysis (LCA), may add to the further understanding of variations in TTO responses.

OBJECTIVES

To identify whether subgroups of respondents can be identified on the basis of their responses to TTO exercises and to investigate which respondent characteristics are associated with membership of the identified subgroups.

METHODS

Members of the Dutch general public, aged 18 to 65 years, completed a Web-based questionnaire concerning sociodemographic characteristics, three TTO exercises valuing health states described using the domains of the EuroQol five-dimensional questionnaire, and preference for quality versus quantity of life. LCA was used to identify patterns in the responses. Predictive variables were included in the final LCA model to identify the particular respondent characteristics that predict subgroup membership.

RESULTS

The sample consisted of 1067 respondents. Four latent classes were identified in the responses to TTO exercises. Two were high traders, focusing on quality of life and trading off a relatively high number of years. The other two were low traders, focusing on length of life. Predictive analyses revealed significant differences between subgroups in terms of age, sex, subjective life expectancy, and preference for quantity over quality of life.

CONCLUSIONS

We showed that distinct classes of respondents can be discerned in TTO responses from the general public, distinguishing subgroups of low and high traders. More research in this area should confirm our findings and investigate their implications for health state valuation exercises.

Head-to-head comparison of health-state values derived by a probabilistic choice model and scores on a visual analogue scale

BACKGROUND

Health states were quantified based on discrete choice (DC) modeling and visual analogue scale (VAS) values using the five-level version of the EQ-5D (EQ-5D-5L). The aim of this study was to determine the extent of the relationship between DC derived values (indirect method) and VAS values (direct method).

METHODS

Data were collected in Canada, the United Kingdom, the Netherlands, and the United States. Respondents were asked to perform paired comparisons between two EQ-5D-5L health states for DC. In total, 400 different EQ-5D-5L states were included. After each DC task, respondents were prompted to score the two states one after another on a VAS. Intraclass correlation coefficients were calculated between DC and VAS values and illuminating graphs were designed.

RESULTS

Approximately 400 respondents participated from each country. High similarity [individual intraclass correlation coefficients (ICC) >0.85] of DC and moderate correspondence of VAS values were observed for the four countries. Cross-country comparison of DC values shows a nonlinear relationship to the VAS values.

CONCLUSION

EQ-5D-5L derived DC and VAS values show a close but nonlinear relationship. Given the obvious biases associated with the VAS, DC methods based on ordinal responses may be a better alternative.

What is the harm? Applying a public health methodology to measure the impact of gambling problems and harm on quality of life

While the PGSI is indeed an established index of problem-gambling symptoms, it nevertheless does not quantify the degree of harm experienced by individuals at different points on the spectrum of gambling problems. The purpose of the present study was to establish the relationship between the PGSI category and health-related quality of life (HRQoL) decrements using a population health (PH) method. Harms reported by gamblers and affected others across the PGSI spectrums were transformed into 798 vignettes. A general population panel (N=786) and experts who work with gamblers (N=51) rated the impact of these vignette descriptions on quality of life using the Time Trade-Off task, and a Visual Analogue Scale incorporating 27 comparison conditions. Disability weights (DW) were then estimated for different levels of gambling symptoms. A DW of 0.44 was estimated for problem gamblers (PG), suggesting a reduction in the effective enjoyment of life by over 4 years for every 10 years in lifespan. Lower—but non-negligible—DWs of .14 and .29 were determined for low- and moderate-risk gamblers. Gambling is compared with a number of other conditions with respect to HRQoL impact. On average, PG harm appears to be similar to that of a manic episode of bipolar disorder and severe alcohol abuse disorder. We discuss advantages, and methodological challenges, in applying PH methods to measuring the severity of gambling problems in terms of HRQoL.Bien que l'indice du jeu excessif (PGSI) soit en effet un indice établi des symptômes liés aux problèmes de jeu, il ne quantifie pas le niveau de préjudice subi par les personnes situées à différents points sur le spectre des problèmes de jeu. Le but de l'étude a été d’établir la relation entre la catégorie PGSI et les écarts à la baisse en lien avec la qualité de vie liée à la santé (QVLS) en utilisant une méthode de santé de la population. Les torts signalés par les joueurs et les personnes touchées dans le spectre PGSI ont été transformés en 798 vignettes. Un groupe de population en général (N = 786) et des experts qui travaillent avec des joueurs compulsifs (N = 51) ont évalué l’incidence de ces descriptions de vignette sur la qualité de vie à l’aide de la tâche Time Trade-Off (marchandage de temps) et une échelle visuelle analogue intégrant 27 conditions de comparaison. Les poids d’incapacité (DW) ont ensuite été estimés pour différents niveaux de symptômes du jeu. Un DW de 0,44 a été estimé pour les joueurs compulsifs, ce qui laisse supposer une diminution de la jouissance réelle de la vie de plus de 4 ans pour chaque tranche de vie de 10 ans. Les DW inférieurs, mais non négligeables, de 0,14 et 0,29 ont été déterminés pour les joueurs à risque faible et modéré. Le jeu est comparé à un certain nombre d’autres conditions en ce qui concerne l’incidence de la qualité de vie liée à la santé (QVLS). En moyenne, le préjudice causé par un joueur compulsif s'apparente à celui d’un épisode maniaque de trouble bipolaire et d’un trouble sévère d’abus d’alcool. Nous discutons des avantages et des défis méthodologiques, en appliquant des méthodes de santé de la population pour mesurer la gravité des problèmes de jeu en termes de QVLS.

Questioning the differences between general public vs. patient based preferences towards EQ-5D-5L defined hypothetical health states

The purpose of this article is to explore whether any differences exist between the general population and patient based preferences towards EQ-5D-5L defined hypothetical health states. The article discusses the role of adaptation and self-interest in valuing health states and it also contributes rigorous empirical evidence to the scientific debate on the differences between the patient and general population preferences towards hypothetical health states. Patient preferences were elicited in 2015 with the EQ-5D-5L questionnaire using time trade-off and discrete choice experiment design and compared to the Spanish general population preferences, which were elicited using identical methods. Patients were chosen on a voluntary basis according to their willingness to participate in the survey. They were recruited from patient organisations and a hospital in Madrid, Spain. 282 metastatic breast cancer patients and 333 rheumatoid arthritis patients were included in the sample. The analysis revealed differences in preferences between the general population and patient groups. Based on the results of our analysis, it is suggested that the differences in preferences stem from patients being more able to accurately imagine "non-tangible" dimensions of health states (anxiety or depression, and pain or discomfort) than the general population with less experience in various health states. However, this does not mean that general public values should not be reflected in utilities derived for coverage decision making.

Employing quality control and feedback to the EQ-5D-5L valuation protocol to improve the quality of data collection

Objectives

In valuing health states using generic questionnaires such as EQ-5D, there are unrevealed issues with the quality of the data collection. The aims were to describe the problems encountered during valuation and to evaluate a quality control report and subsequent retraining of interviewers in improving this valuation.

Methods

Data from the first 266 respondents in an EQ-5D-5L valuation study were used. Interviewers were trained and answered questions regarding problems during these initial interviews. Thematic analysis was used, and individual feedback was provided. After completion of 98 interviews, a first quantitative quality control (QC) report was generated, followed by a 1-day retraining program. Subsequently individual feedback was also given on the basis of follow-up QCs. The Wilcoxon signed-rank test was used to assess improvements based on 7 indicators of quality as identified in the first QC and the QC conducted after a further 168 interviews.

Results

Interviewers encountered problems in recruiting respondents. Solutions provided were: optimization of the time of interview, the use of broader networks and the use of different scripts to explain the project’s goals to respondents. For problems in interviewing process, solutions applied were: developing the technical and personal skills of the interviewers and stimulating the respondents’ thought processes. There were also technical problems related to hardware, software and internet connections. There was an improvement in all 7 indicators of quality after the second QC.

Conclusion

Training before and during a study, and individual feedback on the basis of a quantitative QC, can increase the validity of values obtained from generic questionnaires.

EuroQol Protocols for Time Trade-Off Valuation of Health Outcomes

The time trade-off (TTO) valuation technique is widely used to determine utility values of health outcomes to inform quality-adjusted life-year (QALY) calculations for use in economic evaluation. Protocols for implementing TTO vary in aspects such as the trade-off framework, iteration procedure and its administration model and method, training of respondents and interviewers, and quality control of data collection. The most widely studied and utilized TTO valuation protocols are the Measurement and Valuation of Health (MVH) protocol, the Paris protocol and the EuroQol Valuation Technology (EQ-VT) protocol, all developed by members of the EuroQol Group. The MVH protocol and its successor, the Paris protocol, were developed for valuation of EQ-5D-3L health states. Both protocols were designed for a trained interviewer to elicit preferences from a respondent using the conventional TTO framework with a fixed time horizon of 10 years and an iteration procedure combining bisection and titration. Developed for valuation of EQ-5D-5L health states, the EQ-VT protocol adopted a composite TTO framework and made use of computer technology to facilitate data collection. Training and monitoring of interviewers and respondents is a pivotal component of the EQ-VT protocol. Research is underway aiming to further improve the EuroQol protocols, which form an important basis for the current practice of health technology assessment in many countries.

Dutch Tariff for the Five-Level Version of EQ-5D

BACKGROUND

In 2009, a new version of the EuroQol five-dimensional questionnaire (EQ-5D) was introduced with five rather than three answer levels per dimension. This instrument is known as the EQ-5D-5L. To make the EQ-5D-5L suitable for use in economic evaluations, societal values need to be attached to all 3125 health states.

OBJECTIVES

To derive a Dutch tariff for the EQ-5D-5L.

METHODS

Health state values were elicited during face-to-face interviews in a general population sample stratified for age, sex, and education, using composite time trade-off (cTTO) and a discrete choice experiment (DCE). Data were modeled using ordinary least squares and tobit regression (for cTTO) and a multinomial conditional logit model (for DCE). Model performance was evaluated on the basis of internal consistency, parsimony, goodness of fit, handling of left-censored values, and theoretical considerations.

RESULTS

A representative sample (N = 1003) of the Dutch population participated in the valuation study. Data of 979 and 992 respondents were included in the analysis of the cTTO and the DCE, respectively. The cTTO data were left-censored at -1. The tobit model was considered the preferred model for the tariff on the basis of its handling of the censored nature of the data, which was confirmed through comparison with the DCE data. The predicted values for the EQ-5D-5L ranged from -0.446 to 1.

CONCLUSIONS

This study established a Dutch tariff for the EQ-5D-5L on the basis of cTTO. The values represent the preferences of the Dutch population. The tariff can be used to estimate the impact of health care interventions on quality of life, for example, in context of economic evaluations.

An Empirical Study of Two Alternative Comparators for Use in Time Trade-Off Studies

BACKGROUND

Studies to produce value sets for preference-based measures of health require definition of a full health upper anchor if the values are to be used to calculate quality-adjusted life years. Recent value sets derived for the EQ-5D-5L instrument have described the upper anchor as "full health," whereas older valuation studies for the EQ-5D used "best health state" in the descriptive system (11111). It is unclear whether this change could have led to differences in the values obtained. The objective of this study was to assess differences in time trade-off (TTO) valuations using two different comparators (full health and 11111).

METHODS

Preferences for EQ-5D-5L health states were elicited from a broadly representative sample of the UK general public. TTO data were collected by using computer-assisted personal interviews. Respondents were randomly allocated to one of two arms, each using a different comparator health state. Respondents completed 10 or 11 TTO valuations and a series of follow-up questions examining their interpretations of the term "full health."

RESULTS

Interviews with 443 respondents were completed in 2014. The differences in mean values across arms are mostly small and nonsignificant. The two arms produced data of similar quality. There is evidence of interviewer effects. Health state 11111 was given a value of 1 by 98.2% of the respondents who valued it.

CONCLUSIONS

EQ-5D-5L values elicited by using the composite TTO approach are not greatly affected by the use of full health or 11111 as the comparator health state.

An Investigation of the Feasibility and Cultural Appropriateness of Stated Preference Methods to Generate Health State Values in the United Arab Emirates

BACKGROUND

No five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) value sets are currently available in the Middle East to inform decision making in the region's health care systems.

OBJECTIVES

To test the feasibility of eliciting EQ-5D-5L values from a general public sample in the United Arab Emirates (UAE) using the EuroQol Group's standardized valuation protocol.

METHODS

Values were elicited in face-to-face computer-assisted personal interviews. Adult Emiratis were recruited in public places. Respondents completed 10 time trade-off tasks and 7 discrete choice experiment tasks, followed by debriefing questions about their experience of completing the valuation tasks. Descriptive analyses were used to assess the face validity of the data.

RESULTS

Two hundred respondents were interviewed in December 2013. The face validity of the data appears to be reasonably high. Mean time trade-off values ranged from 0.81 for the mildest health state (21111) to 0.19 for the worst health state in the EQ-5D-5L descriptive system (55555). Health states were rarely valued as being worse than dead (6.2% of all observations; 10% of all valuations of 55555). In a rationality check discrete choice experiment task whereby a health state (55554) was compared with another that logically dominated it (55211), 99.5% of the respondents chose the dominant option. Most of the respondents stated that their religious beliefs influenced their responses to the valuation tasks.

CONCLUSIONS

Our results suggest that it is feasible to generate meaningful health-state values in the UAE, though some adaptation of the methods may be required to improve their acceptability in the UAE (and other countries with predominantly Arab and/or Muslim populations).

Multinational evidence of the applicability and robustness of discrete choice modeling for deriving EQ-5D-5L health-state values

Aims:

To investigate the feasibility of discrete choice experiments for valuing EQ-5D-5L states using computer-based data collection, the consistency of the estimated regression coefficients produced after modeling the preference data, and to examine the similarity of the values derived across countries.

Methods:

Data were collected in Canada, England, The Netherlands, and the United States (US). Interactive software was developed to standardize the format of the choice tasks across countries, except for face-to-face interviewing in England. The choice task required respondents to choose between 2 suboptimal health states. A Bayesian design was used to generate 200 pairs of states that were randomly grouped into 20 blocks. Each respondent completed 1 block of 10 pairs. A main-effects probit model was used to estimate regression coefficients and to derive values.

Results:

Approximately 400 respondents participated from each country. The mean time to perform 1 choice task was between 29.2 (US) and 45.2 (England) seconds. All regression coefficients were statistically significant, except level 2 for Usual Activities in The Netherlands (P=0.51). Predictions for the complete set of 3125 EQ-5D-5L health states were similar for the 4 countries. Intraclass correlation coefficients between the countries were high: from 0.80 (England vs. US) through 0.98 (Canada vs. US).

Conclusions:

Derivation of value sets from the general population using computer-based choice tasks for the EQ-5D-5L is feasible. Parameter estimates were generally consistent and logical, and health-state values were similar across the 4 countries.

The better than dead method: feasibility and interpretation of a valuation study

BACKGROUND

Traditionally, the valuation of health states worse than being dead suffers from two problems: [1] the use of different elicitation methods for positive and negative values, necessitating arbitrary transformations to map negative to positive values; and [2] the inability to quantify that values are time dependent. The Better than Dead (BTD) method is a health-state valuation method where states with a certain duration are compared with being dead. It has the potential to overcome these problems.

OBJECTIVES

To test the feasibility of the BTD method to estimate values for the EQ-5D system.

METHODS

A representative sample of 291 Dutch respondents (aged 18-45 years) was recruited. In a web-based questionnaire, preferences were elicited for a selection of 50 different health states with six durations between 1 and 40 years. Random-effects models were used to estimate the effects of socio-demographic and experimental variables, and to estimate values for the EQ-5D. Test-retest reliability was assessed in 41 respondents.

RESULTS

Important determinants for BTD were a religious life stance [odds ratio 4.09 (2.00-8.36)] and the educational level. The fastest respondents more often preferred health-state scenarios to being dead and had lower test-retest reliability (0.45 versus 0.77 and 0.84 for fast, medium and slow response times, respectively). The results showed a small number of so-called maximal endurable time states.

CONCLUSION

Valuating health states using the BTD method is feasible and reliable. Further research should explore how the experimental setting modifies how values depend on time.

Interim EQ-5D-5L Value Set for Poland: First Crosswalk Value Set in Central and Eastern Europe

OBJECTIVE

To estimate an interim five-level EuroQol five-dimensional (EQ-5D-5L) value set for Poland on the basis of the crosswalk methodology developed by the EuroQol Group.

METHODS

On the basis of data from 3691 respondents from six European countries, the EuroQol Group has developed a method of obtaining interim value sets for the EQ-5D-5L by means of mapping to the available three-level EuroQol five-dimensional (EQ-5D-3L) value sets ("crosswalk" methodology). A significant part of the data in this study came from Polish respondents (n = 972; 26.3%). Poland is the first Central European country with EQ-5D-3L time trade-off-based social value set published. To obtain an interim EQ-5D-5L value set, we applied the crosswalk methodology to the Polish EQ-5D-3L value set.

RESULTS

Estimated Polish values for 3125 EQ-5D-5L health states are presented. Both EQ-5D-5L and EQ-5D-3L value sets have the same range (from -0.523 to 1.000), but different means (0.448 vs. 0.380) and medians (0.483 vs. 0.403), respectively. Proportionately fewer states worse than dead were observed in the EQ-5D-5L (5.4%) value set than in the EQ-5D-3L (13.2%) value set.

CONCLUSIONS

The crosswalk-based value set is available for use in EQ-5D-5L studies in Poland to calculate health state utilities. It should be considered an interim value set until values based on preferences elicited directly from a sample representative of the Polish general population become available. This study helps users of the crosswalk algorithm understand the properties of the EQ-5D-5L values generated using this method, in comparison to EQ-5D-3L values obtained with the Polish time trade-off value set. It is likely that similar results would be observed for values sets in other countries because the same crosswalk methodology applies across all countries.