Lead versus lag-time trade-off variants: does it make any difference?

The natural history and burden of illness of metachromatic leukodystrophy: a systematic literature review

BACKGROUND

Metachromatic leukodystrophy (MLD; OMIM 250100 and 249900) is a rare lysosomal storage disease caused by deficient arylsulfatase A activity, leading to accumulation of sulfatides in the nervous system. This systematic literature review aimed to explore the effect of MLD on the lives of patients.

METHODS

The Ovid platform was used to search Embase, MEDLINE, and the Cochrane Library for articles related to the natural history, clinical outcomes, and burden of illness of MLD; congress and hand searches were performed using 'metachromatic leukodystrophy' as a keyword. Of the 531 publications identified, 120 were included for data extraction following screening. A subset of findings from studies relating to MLD natural history and burden of illness (n = 108) are presented here.

RESULTS

The mean age at symptom onset was generally 16-18 months for late-infantile MLD and 6-10 years for juvenile MLD. Age at diagnosis and time to diagnosis varied widely. Typically, patients with late-infantile MLD presented predominantly with motor symptoms and developmental delay; patients with juvenile MLD presented with motor, cognitive, and behavioral symptoms; and patients with adult MLD presented with cognitive symptoms and psychiatric and mood disorders. Patients with late-infantile MLD had more rapid decline of motor function over time and lower survival than patients with juvenile MLD. Commonly reported comorbidities/complications included ataxia, epilepsy, gallbladder abnormalities, incontinence, neuropathy, and seizures.

CONCLUSIONS

Epidemiology of MLD by geographic regions, quantitative cognitive data, data on the differences between early- and late-juvenile MLD, and humanistic or economic outcomes were limited. Further studies on clinical, humanistic (i.e., quality of life), and economic outcomes are needed to help inform healthcare decisions for patients with MLD.

Testing 2 Alternative Time Trade-Off Methods for Valuation of Children's Health States

OBJECTIVES

Composite time trade-off (cTTO) values for EQ-5D-Y-3L health states tend to be high, raising concerns about sensitivity particularly for mild or moderate health states. We conceptualized and pilot tested 2 alternative time trade-off (TTO) variants: the caregiver TTO (CGTTO) and lag-time TTO (LTTO).

METHODS

We collected CGTTO and LTTO data in China for 10 EQ-5D-Y-3L health states and compared the resulting values, respondent feedback, and task completion times with those from an EQ-5D-Y-3L valuation study using cTTO. We also examined how age and parental status of respondents could affect TTO values.

RESULTS

A total of 304 participants were included in this study. Overall, cTTO showed statistically better results in all feedback questions. On a 5-point Likert scale where lower score means greater agreement, the mean (SD) feedback scores for cTTO, LTTO, and CGTTO were 1.18 (0.58), 1.45 (0.91), and 1.65 (1.02) for "easy to understand"; 1.45 (0.91), 1.94 (1.08), and 1.86 (1.24) for "easy to differentiate"; and 3.61 (1.29), 2.97 (1.33), and 3.02 (1.50) for "difficult to decide," respectively. The mean (SD) TTO values of all 10 states were 0.463 (0.494), 0.387 (0.555), and 0.123 (0.710) for cTTO, LTTO, and CGTTO, respectively. The effects of age and parental status on TTO values differed by the 3 methods.

CONCLUSIONS

LTTO and CGTTO produce values with good characteristics and merit further investigation. Researchers need to be aware of the differences in design and values when using the TTO method to value children's health states.

The Impact of Underlying Conditions on Quality-of-Life Measurement Among Patients with Chronic Wounds, as Measured by Utility Values: A Review with an Additional Study

Significance: Quality of life (QoL) is important to patients with chronic wounds and is rarely formally evaluated. Understanding what comorbidities most affect the individual versus their wounds could be a key metric. Recent Advances: The last 20 years have seen substantial advances in QoL instruments and conversion of patient data to a single value known as the health utilities index (HUI). We review these advances, along with wound-related QoL, and analyze real-world comorbidities challenging wound care. Critical Issues: To understand the impact of underlying comorbidities in a real-world patient population, we examined a convenience sample of 382 patients seen at a hospital-based outpatient wound center. This quality reporting study falls outside the regulations that govern human subject research. Comorbid conditions were used to calculate HUIs using a variety of literature-reported approaches, while Wound-Quality-of-Life (W-QoL) questionnaire data were collected from patients during their first visit. The mean number of conditions per patient was 8; 229 patients (59.9%) had utility values for comorbidities/conditions, which were worse/lower than their wounds' values. Sixty-three (16.5%) patients had depression and/or anxiety, 64 (16.8%) had morbid obesity, and 204 (53.4%) had gait and mobility disorders, all of which could have affected W-QoL scoring. The mean minimum utility value (0.5) was within 0.05 units of an average of 13 studies reporting health utilities from wound care populations using the EuroQol 5 Dimension instrument. Future Directions: The comorbidity associated with the lowest utility value is what might most influence the QoL of patients with chronic wounds. This finding needs further investigation.

Time and lexicographic preferences in the valuation of EQ-5D-Y with time trade-off methodology

In the valuation of EQ-5D-Y-3L, adult respondents are asked to complete composite time trade-off (cTTO) tasks for a 10-year-old child. Earlier work has shown that cTTO utilities elicited in such a child perspective are generally higher than when adults take their own perspective. We explore how differences in time preference in child and adult perspectives could explain this effect. Furthermore, as cTTO valuation in a child perspective involves explicit consideration of immediate death for a child, we also consider how cTTO utilities could be affected by decision-makers lexicographically avoiding death in children. We report the results of an experiment in which 219 respondents valued 5 health states in both adult and child perspectives with either a standard cTTO or a lead-time TTO only approach, in which immediate death is less focal. Time preferences were measured in both perspectives. Our results suggest that utilities were lower when lead-time TTO, rather than cTTO, was used. We find large heterogeneity in time preference in both perspectives, with predominantly negative time preference. The influence of time preferences on utilities, however, was small, and correcting for time preferences did not reduce differences between utilities elicited in both perspectives. Surprisingly, we found more evidence for differences in utilities between adult and child perspectives when lead-time TTO was used. Overall, these results suggest that time and lexicographic preferences affect time trade-off valuation in child and adult perspectives, but are not the explanation for differences between these perspectives. We discuss the implications of our findings for EQ-5D-Y-3L valuation.

Time and lexicographic preferences in the valuation of EQ-5D-Y with time trade-off methodology

In the valuation of EQ-5D-Y-3L, adult respondents are asked to complete composite time trade-off (cTTO) tasks for a 10-year-old child. Earlier work has shown that cTTO utilities elicited in such a child perspective are generally higher than when adults take their own perspective. We explore how differences in time preference in child and adult perspectives could explain this effect. Furthermore, as cTTO valuation in a child perspective involves explicit consideration of immediate death for a child, we also consider how cTTO utilities could be affected by decision-makers lexicographically avoiding death in children. We report the results of an experiment in which 219 respondents valued 5 health states in both adult and child perspectives with either a standard cTTO or a lead-time TTO only approach, in which immediate death is less focal. Time preferences were measured in both perspectives. Our results suggest that utilities were lower when lead-time TTO, rather than cTTO, was used. We find large heterogeneity in time preference in both perspectives, with predominantly negative time preference. The influence of time preferences on utilities, however, was small, and correcting for time preferences did not reduce differences between utilities elicited in both perspectives. Surprisingly, we found more evidence for differences in utilities between adult and child perspectives when lead-time TTO was used. Overall, these results suggest that time and lexicographic preferences affect time trade-off valuation in child and adult perspectives, but are not the explanation for differences between these perspectives. We discuss the implications of our findings for EQ-5D-Y-3L valuation.

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

INTRODUCTION

The standard EQ-5D-Y-3L valuation protocol applies DCE data as the primary preference source to model the relative importance of dimensions while cTTO data served to anchor the DCE coefficients onto the QALY scale. This study aims to estimate an EQ-5D-Y-3L value set for China following this protocol, but with a larger cTTO design to better understand the role of cTTO data in estimating EQ-5D-Y-3L value sets.

METHODS

In total, 150 choice sets and 28 EQ-5D-Y-3L health states were valued using DCE and cTTO methods with two independent samples, respectively. General public from 14 different regions were recruited using quota sampling method to achieve representativeness. We compared two modelling strategies: (1) fit the DCE data with mixed logit model with correlated coefficients and a subsequent mapping procedure for anchoring; (2) fit the DCE and TTO data jointly in a hybrid model. Two evaluation criteria (1) coefficient significance and monotonicity; (2) prediction accuracy of the observed cTTO values were used to select the value set.

RESULTS

In total, 1476 individuals participated in the study, with 1058 participated the DCE interview and 418 participated the cTTO interview. The highest mean TTO value was 0.924 for state 11112 and the lowest mean TTO value was - 0.088 for state 33333. The hybrid model with an A3 term performed the best and was selected as the value set.

DISCUSSION

Following the international protocol and using a larger cTTO design, this study established the EQ-5D-Y-3L value set using a hybrid model for China. Future EQ-5D-Y-3L valuation study could consider using a larger cTTO design for estimating the value set.

Valuing EQ-5D-Y: the current state of play

BACKGROUND

For nearly a decade, value sets for the EQ-5D-Y were not available, reflecting challenges in valuing child HRQoL. A methodological research programme led to publication of a valuation protocol in 2020, which was rapidly taken up by local study teams. By the end of 2022, between 11 and 17 EQ-5D-Y value sets will be available, more than for any other child HRQoL measure. It is timely to review the experience of those using the protocol to identify early learnings and remaining issues where more research is needed.

METHODS

In June 2021, the EuroQol Group organised a three-day workshop, bringing together all those involved in EQ-5D-Y value set studies and related methodological research concerning EQ-5D-Y and valuation. Workshop discussions were captured by note taking and recording all sessions and online chat. A narrative summary of all sessions was produced and synthesised to identify points of agreement and aspects of methods where uncertainty remains.

RESULTS

There was broad agreement that DCE is working well as the principal valuation method. However, the most appropriate means of anchoring the latent scale values produced by DCE remains unclear. Some studies have deviated from the protocol by extending the number of states included in TTO tasks, to better support modelling of DCE and TTO. There is ongoing discussion about the relative merits of alternative variants of TTO and other methods for anchoring. Very few studies have consulted with local end-users to gauge the acceptability of methods used to value EQ-5D-Y.

CONCLUSIONS

Priority areas for research include testing alternative methods for anchoring DCE data; exploring the preferences of adolescents; and scale differences in values for EQ-5D-Y and adult EQ-5D states, and implications of such differences for the use of EQ-5D-Y values in HTA. Given the normative elements of the protocol, engaging with HTA bodies and other local users should be the first step for all future value set studies. Value sets undertaken to date are for the three-level EQ-5D-Y. However, the issues discussed in this paper are equally relevant to valuation of the five-level version of EQ-5D-Y; indeed, similar challenges are encountered valuing any measure of child HRQoL.

Behavioral Theories That Have Influenced the Way Health State Preferences Are Elicited and Interpreted: A Bibliometric Mapping Analysis of the Time Trade-Off Method With VOSviewer Visualization

Aim

The aim of this paper is to develop an understanding of how behavioral theories have influenced the way preferences for health-related quality of life are elicited and interpreted. We focus on the Time Trade-off (TTO) method given it represents the quality-adjusted life-year (QALY) concept-that survival in less-than-full health can be deemed equivalent to a shorter survival in full health. To our knowledge this is the first review using a combination of systematic scoping review, bibliometrics and VOSviewer visualization to map the development of ideas in health economics.

Methods

A priori, we selected three behavioral theories to explore within our review, referred to here as Expected Utility Theory, Non-Expected Utility Theory and Probabilistic Choice Theory. A fourth topic, Order Effects, is defined broadly to encompass behavioral theories around timing/sequence of events. For the main search, Scopus was used to identify literature that had (a) elicited TTO values and/or (b) contributed to the way TTO values were elicited and interpreted, from inception to July 2021. Papers that focused on the latter category were given the label "behavioral" and underwent additional analyses. A two stage-screening was applied to assess eligibility. Co-citation, co-authorship and co-occurrence of keywords was used to chart the development of TTO over time.

Results

A total of 1,727 records were retrieved from Scopus and were supplemented by an additional 188 papers. There were 856 applied and 280 behavioral papers included in the final corpus, with the behavioral set split equally into four sets of 70 papers to chart the development of keywords over time: (1) 1972-1999; (2) 2000-2010, (3) 2010-2015 and (4) 2015-2021.

Discussion

The keyword analysis suggested that whilst some ideas transition quickly from economic theory to the TTO literature, such as the impact of Order Effects, others take longer to be assimilated, for example Non-Expected Utility models or failure of constant discounting. It is therefore important that researchers within health economics work more closely with those in mainstream economics and keep abreast of the wider economics and behavioral sciences to expedite the uptake of new and relevant ideas.

Developing a preference-based measure for weight-specific health-related quality of life in adolescence: the WAItE UK valuation study protocol

INTRODUCTION

Adolescent obesity is a public health problem in the UK. The Weight-Specific Adolescent Instrument for Economic Evaluation (WAItE) has been developed as the first weight-specific health-related quality of life measure appropriate for economic evaluation, but currently cannot be used to generate quality-adjusted life years (QALYs), which are the basis of cost-utility analysis. Generic measures (such as the EQ-5D-Y or CHU-9D) may be insensitive to small but important health changes in overweight or obese adolescents. This study aims to generate a preference-based scoring algorithm for the WAItE.

METHODS AND ANALYSIS

A discrete choice experiment (DCE) will be administered to value health states described by the WAItE classification system. These health states will be presented to members of the adult general population of the UK via an online survey. A range of regression models will be used to produce the utility algorithm for the WAItE. The DCE-visual analogue scale and time trade-off (TTO) anchoring methods will be used anchor the value set on to the 0-1 QALY scale.

ETHICS AND DISSEMINATION

The Newcastle University Medical School Ethics Committee approved the study (references 4772/2020 (DCE) and 9978/2020 (TTO)). The developed algorithm can be applied to future economic evaluations of weight management interventions and treatments for adolescents.

Psychometric properties of the EQ-5D-5L: a systematic review of the literature

PURPOSE

Although the EQ-5D has a long history of use in a wide range of populations, the newer five-level version (EQ-5D-5L) has not yet had such extensive experience. This systematic review summarizes the available published scientific evidence on the psychometric properties of the EQ-5D-5L.

METHODS

Pre-determined key words and exclusion criteria were used to systematically search publications from 2011 to 2019. Information on study characteristics and psychometric properties were extracted: specifically, EQ-5D-5L distribution (including ceiling and floor), missing values, reliability (test-retest), validity (convergent, known-groups, discriminate) and responsiveness (distribution, anchor-based). EQ-5D-5L index value means, ceiling and correlation coefficients (convergent validity) were pooled across the studies using random-effects models.

RESULTS

Of the 889 identified publications, 99 were included for review, representing 32 countries. Musculoskeletal/orthopedic problems and cancer (n = 8 each) were most often studied. Most papers found missing values (17 of 17 papers) and floor effects (43 of 48 papers) to be unproblematic. While the index was found to be reliable (9 of 9 papers), individual dimensions exhibited instability over time. Index values and dimensions demonstrated moderate to strong correlations with global health measures, other multi-attribute utility instruments, physical/functional health, pain, activities of daily living, and clinical/biological measures. The instrument was not correlated with life satisfaction and cognition/communication measures. Responsiveness was addressed by 15 studies, finding moderate effect sizes when confined to studied subgroups with improvements in health.

CONCLUSIONS

The EQ-5D-5L exhibits excellent psychometric properties across a broad range of populations, conditions and settings. Rigorous exploration of its responsiveness is needed.

An exploration of methods for obtaining 0 = dead anchors for latent scale EQ-5D-Y values

OBJECTIVES

Discrete choice experiments (DCEs) can be used to obtain latent scale values for the EQ-5D-Y, but these require anchoring at 0 = dead to meet the conventions of quality-adjusted life year (QALY) estimation. The primary aim of this study is to compare four preference elicitation methods for obtaining anchors for latent scale EQ-5D-Y values.

METHODS

Four methods were tested: visual analogue scale (VAS), DCE (with a duration attribute), lag-time time trade-off (TTO) and the location-of-dead (LOD) approach. In computer-assisted personal interviews, UK general public respondents valued EQ-5D-3L health states from an adult perspective and EQ-5D-Y health states from a 10-year-old child perspective. Respondents completed valuation tasks using all four methods, under both perspectives.

RESULTS

349 interviews were conducted. Overall, respondents gave lower values under the adult perspective compared to the child perspective, with some variation across methods. The mean TTO value for the worst health state (33333) was about equal to dead in the child perspective and worse than dead in the adult perspective. The mean VAS rescaled value for 33333 was also higher in the child perspective. The DCE produced positive child perspective values and negative adult perspective values, though the models were not consistent. The LOD median rescaled value for 33333 was negative under both perspectives and higher in the child perspective.

DISCUSSION

There was broad agreement across methods. Potential criteria for selecting a preferred anchoring method are presented. We conclude by discussing the decision-making circumstances under which utilities and QALY estimates for children and adults need to be commensurate to achieve allocative efficiency.

A General Population Utility Valuation Study for Metastatic Epidural Spinal Cord Compression Health States

STUDY DESIGN

General population utility valuation study.

OBJECTIVE

This study obtained utility valuations from a Canadian general population perspective for 31 unique metastatic epidural spinal cord compression (MESCC) health states and determined the relative importance of MESCC-related consequences on quality-of-life.

SUMMARY OF BACKGROUND DATA

Few prospective studies on the treatment of MESCC have collected quality-adjusted-life-year weights (termed "utilities"). Utilities are an important summative measure which distills health outcomes to a single number that can assist healthcare providers, patients, and policy makers in decision making.

METHODS

We recruited a sample of 1138 adult Canadians using a market research company. Quota sampling was used to ensure that the participants were representative of the Canadian population in terms of age, sex, and province of residence. Using the validated MESCC module for the "Self-administered Online Assessment of Preferences" (SOAP) tool, participants were asked to rate six of the 31 MESCC health states, each of which presented varying severities of five MESCC-related dysfunctions (dependent; non-ambulatory; incontinent; pain; other symptoms).

RESULTS

Participants equally valued all MESCC-related dysfunctions which followed a pattern of diminishing marginal disutility (each additional consequence resulted in a smaller incremental decrease in utility than the previous). These results demonstrate that the general population values physical function equal to other facets of quality-of-life.

CONCLUSION

We provide a comprehensive set of ex ante utility estimates for MESCC health states that can be used to help inform decision making. This is the first study reporting direct utility valuation for a spinal disorder. Our methodology offers a feasible solution for obtaining quality-of-life data without collecting generic health status questionnaire responses from patients.

LEVEL OF EVIDENCE

4.

How Prevalent Are Implausible EQ-5D-5L Health States and How Do They Affect Valuation? A Study Combining Quantitative and Qualitative Evidence

BACKGROUND

When designing a valuation study, a criterion that has been used for selecting health states for direct valuation is whether the health states are plausible for respondents, because it is assumed that inclusion of implausible states would compromise data quality.

OBJECTIVES

To understand which health states are implausible, and how their values differ from the values of the plausible counterparts.

METHODS

One thousand six hundred Chinese students valued all 3125 health states of the 5-level EuroQol 5-dimensional questionnaire (EQ-5D-5L) using the EuroQol visual analogue scale. Of these, 890 students also indicated whether each valued state was implausible or not using a binary scale. Additional qualitative interviews were conducted concerning the thought processes involved in the valuation of implausible states. We calculated an implausible score for each state. Then we examined the effect of implausibility on visual analogue scale values by fitting 2 regression models. Two independent researchers analyzed the qualitative transcripts using thematic analysis.

RESULTS

Approximately 30% of the EQ-5D-5L health states were rated as implausible by at least 50% of the respondents, but there was substantial heterogeneity in views about the plausibility of EQ-5D-5L states. Health states with dimensions that conflicted were more likely to be judged as implausible states. Health states that respondents deemed as implausible were more difficult to value and had lower values.

CONCLUSIONS

When respondents found the EQ-5D states to be implausible, they tended to give them lower values. Nevertheless, completely excluding implausible states from a valuation study is not possible because there is a lack of agreement among respondents on which states are implausible.

The Psychometric Properties of a Self-Administered, Open-Source Module for Valuing Metastatic Epidural Spinal Cord Compression Utilities

INTRODUCTION

Web surveys are often used for utility valuation. Typically, custom utility valuation tools that have not undergone psychometric evaluation are used.

OBJECTIVES

This study aimed to determine the psychometric properties of a metastatic epidural spinal cord compression (MESCC) module run on a customizable open-source, internet-based, self-directed utility valuation platform (Self-directed Online Assessment of Preferences [SOAP]).

METHODS

Individuals accompanying patients to the emergency department waiting room in Ottawa, Canada, were recruited. Participants made SOAP MESCC health state valuations in the waiting room and 48 h later at home. Validity, agreement reliability, and responsiveness were measured by logical consistency of responses, smallest detectable change, the interclass correlation coefficient, and Guyatt's responsiveness index, respectively.

RESULTS

Of 285 participants who completed utility valuations, only 113 (39.6%) completed the re-test. Of these 113 participants, 92 (81.4%) provided valid responses on the first test and 75 (66.4%) provided valid responses on the test and re-test. Agreement for all groups of health states was adequate, since their smallest detectable change was less than the minimal clinically important difference. The mean interclass correlation coefficients for all health states were > 0.8, indicating at least substantial reliability. Guyatt's responsiveness indices all exceeded 0.80, indicating a high level of responsiveness.

CONCLUSIONS

To our knowledge, this is the first validated open-source, web-based, self-directed utility valuation module. We have demonstrated the SOAP MESCC module is valid, reproducible, and responsive for obtaining ex ante utilities. Considering the successful psychometric validation of the SOAP MESCC module, other investigators can consider developing modules for other diseases where direct utility valuation is needed.

Development of one general and six country-specific algorithms to assess societal health utilities based on ASAS HI

Objective

Health utilities represent preference values that persons attach to health states. This study aims to develop one general and six country-specific algorithms to calculate societal preference values for health of patients with spondyloarthritis (SpA), as assessed by the disease-specific Assessment of SpondyloArthritis international Society Health Index (ASAS HI).

Methods

A survey was performed in random population samples from six European countries. In a best-worst choice experiment, subjects were asked to indicate repeatedly which of 4 random aspects of the 17-item ASAS HI was were most and least important. Bayesian analysis provided the relative importance of each of the 17 items. To rescale the relative importance scores on the absolute utility scale between 0 and 1, participants additionally completed two lead time trade-off experiments, one for 'severe SpA' and one for 'best health' without SpA. Six country-specific algorithms and one general algorithm were derived. The general algorithm was tested in 199 patients with axial SpA (axSpA).

Results

3039 subjects, mean age 47 years (SD 15) and 52% female completed the experiments. The population's health utility value for SpA varied between - 0.24 for 'worst' SpA (country range -0.35 to 0.03), and 0.88 for 'best' health (country range 0.81 to 0.90). Among 199 patients with axSpA, the mean utility was 0.36 (SD 0.30, range -0.24 to 0.88) and discriminated well between patients having high (Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) ≥ 4) or low (BASDAI < 4) disease activity (0.18 (SD 0.24) vs 0.51(SD 0.27), p<0.01).

Conclusion

One general and six country-specific algorithms are available to convert scores from the ASAS HI into disease-specific societal utility values.

Valuing health states: is the MACBETH approach useful for valuing EQ-5D-3L health states?

BACKGROUND

Quality Adjusted Life Years (QALYs) are a key outcome measure widely used within health technology assessment and health service research studies. QALYs combine quantity and quality of life, with quality of life calculations relying on the value of distinct health states. Such health states' values capture the preferences of a population and have been typically built through numerical elicitation methods. Evidence points to these value scores being influenced by methods in use and individuals reporting cognitive difficulties in eliciting their preferences. Evidence from other areas has further suggested that individuals may prefer using distinct elicitation techniques and that this preference can be influenced by their numeracy. In this study we explore the use of the MACBETH (Measuring Attractiveness by a Categorical Based Evaluation Technique) non-numerical preference elicitation approach for health states' evaluation.

METHODS

A new protocol for preference elicitation based on MACBETH (only requiring qualitative judgments) was developed and tested within a web survey format. A sample of the Portuguese general population (n=243) valued 25 EQ-5D-3L health states with the MACBETH protocol and with a variant of the time trade-off (TTO) protocol, for comparison purposes and for understanding respondents' preference for distinct protocols and differences in inconsistent evaluations. Respondents answered to a short numeracy test, and basic socio-economic information collected.

RESULTS

Results show that the mean values derived from MACBETH and the TTO variant are strongly correlated; however, there are substantial differences for several health states' values. Large and similar numbers of logical inconsistencies were found in respondents' answers with both methods. Participants with higher levels of numeracy according to the test preferred expressing value judgments with MACBETH, while participants with lower levels were mostly indifferent to both methods. Higher correlations between MACBETH and TTO variant evaluations were observed for individuals with higher numeracy.

CONCLUSION

Results suggest that it is worth researching the use of non-numerical preference elicitation methods. Numeracy tests more appropriate for preference elicitation when no explicit considerations of uncertainty are made need to be explored and used. Further behavioural research is needed to fully understand the potential for using these methods in distinct settings (e.g. in different evaluation contexts and in face-to-face and non-face-to-face environments), as well as to explore the effect of literacy on assessments and on respondents' preferences.

Peer effects in health valuation: the relation between rating of contemporaries' health and own health

Background

Most health valuation studies assume that individuals’ health valuations do not depend on social comparisons. However, there is some evidence that this assumption is not satisfied in practice. This paper tests whether self-rated health by means of a Visual Analogue Scale (VAS) is related to how one perceives the health of one’s contemporaries, while accounting for one’s health as classified by the EQ-5D classification system.

Methods

In a large sample (n = 1500), representative of the general public, we use a VAS to rate respondents’ own health and their assessment of their contemporaries’ health. In addition, we directly ask them whether they perceive their health to be better, the same, or worse than their contemporaries, and we measure their own health according to the EQ-5D-5 L.

Results

We find a positive relationship between own health rating and contemporaries’ health rating, after controlling for the respondents’ own health as classified according to the EQ-5D. Furthermore, we observe a discrepancy between relative health vis-à-vis age peers as measured by an ordinal comparison and relative health as measured by a VAS. Finally, respondents, especially women, tended to overestimate the health of other people of their age.

Conclusions

We provide evidence that people’s own health rating is related to the perception of health of contemporaries. Our results indicate that knowledge about a respondent’s perception of others’ health is useful in explaining health state valuations.

Evaluation of Split Version and Feedback Module on the Improvement of Time Trade-Off Data

BACKGROUND

EQ-5D-5L valuation studies previously reported many inconsistent responses in time trade-off (TTO) data. A number of possible elements, including ordering effects of the valuation tasks, mistakes at the sorting question, and interviewers' (learning) effects, may contribute to their inconsistency.

OBJECTIVES

This study aimed to evaluate the effect of two modifications on consistency of TTO data in The Netherlands (NL) and Hong Kong (HK): (1) separating the valuation of the Better than Dead (BTD) and Worse than Dead (WTD) states; and (2) Implementation of feedback (FB) module by offering an opportunity to review TTO responses.

METHODS

A crossover design with two study arms was used to test the effect of the modifications. In each jurisdiction, six interviewers were involved where half the interviewers started using the standard version, and the other half started with the split version. Each version was switched after every 25 (NL) or 30 (HK) interviews until 400 interviews were completed.

RESULTS

In the NL and HK, 404 and 403 respondents participated, respectively. With the use of the FB module, the proportion of respondents with inconsistent responses was lowered from 17.8% to 10.6% (P < 0.001) in NL and from 31.8% to 22.3% (P = 0.003) in HK. The result of separating the valuation of BTD and WTD states was not straightforward because it reduced the inconsistency rate in NL but not in HK.

CONCLUSIONS

The results support implementation of the FB module to promote the consistency of the data. The separation of the BTD and WTD task is not supported.

Handling Data Quality Issues to Estimate the Spanish EQ-5D-5L Value Set Using a Hybrid Interval Regression Approach

BACKGROUND

The Spanish five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) valuation study was the first to use the EuroQol Valuation Technology protocol, including composite time trade-off (C-TTO) and discrete choice experiments (DCE). In this study, its investigators noticed that some interviewers did not fully explain the C-TTO task to respondents. Evidence from a follow-up study in 2014 confirmed that when interviewers followed the protocol, the distribution of C-TTO responses widened.

OBJECTIVES

To handle the data quality issues in the C-TTO responses by estimating a hybrid interval regression model to produce a Spanish EQ-5D-5L value set.

METHODS

Four different models were tested. Model 0 integrated C-TTO and DCE responses in a hybrid model and models 1 to 3 altered the interpretation of the C-TTO responses: model 1 allowed for censoring of the C-TTO responses, whereas model 2 incorporated interval responses and model 3 included the interviewer-specific protocol violations. For external validation, the predictions of the four models were compared with those of the follow-up study using the Lin's concordance correlation coefficient.

RESULTS

This stepwise approach to modeling C-TTO and DCE responses improved the concordance between the valuation and follow-up studies (concordance correlation coefficient: 0.948 [model 0], 0.958 [model 1], 0.952 [model 2], and 0.989 [model 3]). We recommend the estimates from model 3, because its hybrid interval regression model addresses the data quality issues found in the valuation study.

CONCLUSIONS

Protocol violations may occur in any valuation study; handling them in the analysis can improve external validity. The resulting EQ-5D-5L value set (model 3) can be applied to inform Spanish health technology assessments.

Assessing the Use of a Feedback Module to Model EQ-5D-5L Health States Values in Hong Kong

BACKGROUND

An international valuation protocol exists for obtaining societal values for each of the 3125 health states of the five-level EuroQol-five dimensions (EQ-5D-5L) questionnaire. A feedback module (FM) that can be related to theoretical models used in behavioral economics was recently included in this protocol.

OBJECTIVES

Our objective was to assess the impact of using an FM to estimate an EQ-5D-5L value set in Hong Kong.

METHODS

EQ-5D-5L health states were elicited using a composite time trade-off (C-TTO) and a discrete-choice (DC) experiment. Use of the FM according to participant characteristics and the impact of the FM on the number of inconsistent C-TTO responses were assessed. We employed a main-effects hybrid model that combined data from both elicitation techniques.

RESULTS

In total, 1014 individuals completed the survey. The sample was representative of the general Chinese Hong Kong population in terms of sex, educational attainment, marital status, and most age groups but not for employment status. The use of the FM reduced the number of C-TTO inconsistencies. Participant characteristics differed significantly between those who used and did not use the FM. The model without a constant resulted in logical consistent coefficients and was therefore selected as the model to produce the value set. The predicted EQ-5D-5L values ranged from -0.864 to 1.

CONCLUSIONS

The use of an FM to allow participants to exclude C-TTO responses reduced the number of inconsistent responses and improved the quality of the data when estimating an EQ-5D-5L value set in Hong Kong.

Valuation and Modeling of EQ-5D-5L Health States Using a Hybrid Approach

Supplemental Digital Content is available in the text.

Background:

The EQ-5D instrument is the most widely used preference-based health-related quality of life questionnaire in cost-effectiveness analysis of health care technologies. Recently, a version called EQ-5D-5L with 5 levels on each dimension was developed. This manuscript explores the performance of a hybrid approach for the modeling of EQ-5D-5L valuation data.

Methods:

Two elicitation techniques, the composite time trade-off, and discrete choice experiments, were applied to a sample of the Spanish population (n=1000) using a computer-based questionnaire. The sampling process consisted of 2 stages: stratified sampling of geographic area, followed by systematic sampling in each area. A hybrid regression model combining composite time trade-off and discrete choice data was used to estimate the potential value sets using main effects as starting point. The comparison between the models was performed using the criteria of logical consistency, goodness of fit, and parsimony.

Results:

Twenty-seven participants from the 1000 were removed following the exclusion criteria. The best-fitted model included 2 significant interaction terms but resulted in marginal improvements in model fit compared to the main effects model. We therefore selected the model results with main effects as a potential value set for this methodological study, based on the parsimony criteria. The results showed that the main effects hybrid model was consistent, with a range of utility values between 1 and −0.224.

Conclusion:

This paper shows the feasibility of using a hybrid approach to estimate a value set for EQ-5D-5L valuation data.

Quality Control Process for EQ-5D-5L Valuation Studies

BACKGROUND

The values of the five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) are elicited using composite time trade-off and discrete choice experiments. Unfortunately, data quality issues and interviewer effects were observed in the first few EQ-5D-5L valuation studies. To prevent these issues from occurring in later studies, the EuroQol Group established a cyclic quality control (QC) process.

OBJECTIVES

To describe this QC process and show its impact on data quality.

METHODS

A newly developed QC tool provided information about protocol compliance, interviewer effects, and mean values by health state severity. In a cyclic process, this information is initially used to evaluate whether new interviewers meet minimal quality requirements and later to provide feedback about how their performance may be improved. To investigate the impact of this cyclic process, we compared the quality of the data in Dutch and Spanish valuation studies that did not have this QC process with that in the follow-up studies in the same countries that used the QC process. Data quality was measured using protocol violations, variability between interviewers, the proportion of inconsistent responders, and clustering of composite time trade-off values.

RESULTS

In Spain, protocol violations were reduced from 87% in the valuation study to 5% in the follow-up study and in the Netherlands from 20% to 8%. In both countries, interviewers performed more homogeneously in the follow-up studies. The number of inconsistent respondents was reduced by 23.2% in Spain and 23.6% in the Netherlands. Values were less clustered in the follow-up studies.

CONCLUSIONS

The implementation of a strict QC process in EQ-5D-5L valuation studies increases interviewer protocol compliance and promotes data quality.

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.

Comparison of Value Set Based on DCE and/or TTO Data: Scoring for EQ-5D-5L Health States in Japan

BACKGROUND

The valuation study of the five-level version of the EuroQol five-dimensional questionnaire (EQ-5D-5L) involved composite time trade-off (cTTO) and a discrete choice experiment (DCE). The DCE scores must be anchored to the quality-of-life scale from 0 (death) to 1 (full health). Nevertheless, the characteristics of the statistical methods used for converting the EQ-5D-5L DCE results by using TTO information are not yet clearly known.

OBJECTIVES

To present the Japanese DCE value set of the EQ-5D-5L and compare three methods for converting latent DCE values.

METHODS

The survey sampled the general population at five locations in Japan. 1098 respondents were stratified by age and sex. To obtain and compare the value sets of the EQ-5D-5L, the cTTO and DCE data were analyzed by a linear mixed model and conditional logit, respectively. The DCE scores were converted to the quality-of-life scale by anchoring to the worst state using cTTO, mapping DCE onto cTTO, and a hybrid model.

RESULTS

The data from 1026 respondents were analyzed. All the coefficients in the cTTO and DCE value sets were consistent throughout all the analyses. Compared with the cTTO algorithm, the mapping and hybrid methods yielded very similar scoring coefficients. The hybrid model results, however, produced a lower root mean square error and fewer health states with errors exceeding 0.05 than did the other models. The DCE anchored to the worst state overestimated the cTTO scores of almost all the health states.

CONCLUSIONS

Japanese value sets based on DCE were demonstrated. On comparing the observed cTTO scores, we found that the hybrid model was slightly superior to the simpler methods, including the TTO model.

Does the Introduction of the Ranking Task in Valuation Studies Improve Data Quality and Reduce Inconsistencies? The Case of the EQ-5D-5L

BACKGROUND

Time trade-off (TTO)-based valuation studies for the three-level version of the EuroQol five-dimensional questionnaire (EQ-5D) typically started off with a ranking task (ordering the health states by preference). This was not included in the protocol for the five-level EQ-5D (EQ-5D-5L) valuation study.

OBJECTIVES

To test whether reintroducing a ranking task before the composite TTO (C-TTO) could help to reduce inconsistencies in C-TTO responses and improve the data quality.

METHODS

Respondents were randomly assigned to three study arms. The control arm was the present EQ-5D-5L study protocol, without ranking. The second arm (ranking without sorting) preceded the present protocol by asking respondents to rank the target health states using physical cards. The states were then valued in random order using C-TTO. In the third arm (ranking and sorting), the ranked states remained visible through the C-TTO tasks and the order of valuation was determined by the ranking. The study used only 10 EQ-5D-5L health states. We compared the C-TTO-based inconsistent pairs of health states and ties.

RESULTS

The final sample size was 196 in the control arm, 205 in the ranking without sorting arm, and 199 in the ranking and sorting arm. The percentages of ties by respondents were 15.1%, 12.5%, and 12.6% for the control arm, the ranking without sorting arm, and the ranking and sorting arm, respectively. The extra cost for adding the ranking task was about 15%.

CONCLUSIONS

The benefit does not justify the effort involved in the ranking task. For this reason, the addition of the ranking task to the present EQ-5D-5L valuation protocol is not an attractive option.

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.

Valuing Child Health Utility 9D Health States with Young Adults: Insights from a Time Trade Off Study

OBJECTIVES

In contrast to the proliferation of studies incorporating health state values from adults of all ages, relatively few studies have reported upon the application of the time trade off (TTO) approach to generate health state values from populations of younger adults. This study sought to employ a conventional TTO approach to obtain values for a selection of Child Health Utility 9D (CHU9D) health states from a sample of young adults aged 18-29 years and to compare with the values generated from application of the original UK adult standard gamble scoring algorithm and the Australian adolescent scoring algorithm.

METHODS

A convenience sample of Flinders University undergraduate students aged 18-29 years were invited to participate in an interviewer administered conventional TTO task to value a series of five CHU9D health impairment states using the widely used variant developed by the York EQ-5D team.

RESULTS

A total of 152 students within the target age range were approached to participate in the study of whom n = 38 consented to participate, giving an overall participation rate of 25%. With the exception of one health state, the mean TTO values were consistently lower than those generated from application of the original scoring algorithm for the CHU9D elicited with adults of all ages. A significant proportion of participants (n = 17, 45%) considered the most severe CHU9D (PITS) state to be worse than death.

CONCLUSIONS

This study adds to a growing body of evidence indicating that the values attached to identical health states are typically lower for younger people in comparison with adults of all ages and dependent upon the elicitation method utilised. The values obtained are applicable for re-scaling raw CHU9D health state values obtained from younger adolescent samples using profile case best-worst scaling.

An EQ-5D-5L value set based on Uruguayan population preferences

PURPOSE

To derive a value set from Uruguayan general population using the EQ-5D-5L questionnaire and report population norms.

METHODS

General population individuals were randomly assigned to value 10 health states using composite time trade off and 7 pairs of health states through discrete choice experiments. A stratified sampling with quotas by location, gender, age and socio-economic status was used to respect the Uruguayan population structure. Trained interviewers conducted face-to-face interviews. The EuroQol valuation technology was used to administer the protocol as well as to collect the data. OLS and maximum likelihood robust regression models with or without interactions were tested.

RESULTS

We included 794 respondents between 20 and 83 years. Their characteristics were broadly similar to the Uruguayan population. The main effects robust model was chosen to derive social values. Values ranged from -0.264 to 1. States with a misery index = 6 had a mean predicted value of 0.965. When comparing the Uruguayan population with the Argentinian EQ-5D-5L crosswalk value set, the prediction for states which differed from full health only in having one of the dimensions at level 2 were about 0.05 higher in Uruguay. The mean index value, using the selected Uruguayan EQ-5D-5L value set, for the general population in Uruguay was 0.895. In general, older people had worse values and males had slightly better values than females.

CONCLUSION

We derived the EQ-5D-5L Uruguayan value set, the first in Latin America. These results will help inform decision-making using economic evaluations for resource allocation decisions.

How dead is dead? Qualitative findings from participants of combined traditional and lead-time time trade-off valuations

PURPOSE

The EuroQol Valuation Technology (EQ-VT) uses traditional time trade-off (tTTO) for health states better than dead and lead-time TTO (LT-TTO) for states worse than dead to elicit a value (-1.0 to +1.0) for each health state. In the Canadian EQ-5D-5L Valuation study which used the EQVT platform, we observed an unexpected peak in frequency of "0" values and few negative values, particularly in the range of 0 to -0.5. To better understand this finding, we sought to explore respondents' thought processes while valuing a health state, and their understanding of the tTTO and LT-TTO exercises.

METHODS

Qualitative semi-structured interviews were conducted with EQVT task respondents. Questions focused on valuations of health states as: (a) Same as dead in tTTO, (b) Worse than dead in tTTO but changed to same as dead in LT-TTO, (c) Worse than dead in LT-TTO, and (d) Worse than dead in LT-TTO with trading off all 10 years. Data were analyzed using content and thematic analysis.

RESULTS

Mean age of participants (N = 70) was 40 ± 18.1 years, 60% female, and 76% Caucasian. Participants provided similar reasons for valuing a health state same as or worse than dead. Many participants expressed confusion about worse than dead valuations, distinction between same as and worse than dead, and the transition from tTTO to LT-TTO. A few indicated that the addition of 10 years of full health in the LT-TTO influenced their valuations.

CONCLUSIONS

The transition from tTTO to LT-TTO in the EQVT was confusing to participants, whereby some health state valuations around this transition appeared to be arbitrary.

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.

Introducing the composite time trade-off: a test of feasibility and face validity

INTRODUCTION

This study was designed to test the feasibility and face validity of the composite time trade-off (composite TTO), a new approach to TTO allowing for a more consistent elicitation of negative health state values.

METHODS

The new instrument combines a conventional TTO to elicit values for states regarded better than dead and a lead-time TTO for states worse than dead.

RESULTS

A total of 121 participants completed the composite TTO for ten EQ-5D-5L health states. Mean values ranged from -0.104 for health state 53555 to 0.946 for 21111. The instructions were clear to 98 % of the respondents, and 95 % found the task easy to understand, indicating feasibility. Further, the average number of steps taken in the iteration procedure to achieve the point of indifference in the TTO and the average duration of each task were indicative of a deliberate cognitive process.

CONCLUSION

Face validity was confirmed by the high mean values for the mild health states (>0.90) and low mean values for the severe states (<0.42). In conclusion, this study demonstrates the feasibility and face validity of the composite TTO in a face-to-face standardized computer-assisted interview setting.