Utility Values for the CP-6D, a Cerebral Palsy-Specific Multi-Attribute Utility Instrument, Using a Discrete Choice Experiment

A scoping review to create a framework for the steps in developing condition-specific preference-based instruments de novo or from an existing non-preference-based instrument: use of item response theory or Rasch analysis

BACKGROUND

There is no widely accepted framework to guide the development of condition-specific preference-based instruments (CSPBIs) that includes both de novo and from existing non-preference-based instruments. The purpose of this study was to address this gap by reviewing the published literature on CSPBIs, with particular attention to the application of item response theory (IRT) and Rasch analysis in their development.

METHODS

A scoping review of the literature covering the concepts of all phases of CSPBI development and evaluation was performed from MEDLINE, Embase, PsychInfo, CINAHL, and the Cochrane Library, from inception to December 30, 2022.

RESULTS

The titles and abstracts of 1,967 unique references were reviewed. After retrieving and reviewing 154 full-text articles, data were extracted from 109 articles, representing 41 CSPBIs covering 21 diseases or conditions. The development of CSPBIs was conceptualized as a 15-step framework, covering four phases: 1) develop initial questionnaire items (when no suitable non-preference-based instrument exists), 2) establish the dimensional structure, 3) reduce items per dimension, 4) value and model health state utilities. Thirty-nine instruments used a type of Rasch model and two instruments used IRT models in phase 3.

CONCLUSION

We present an expanded framework that outlines the development of CSPBIs, both from existing non-preference-based instruments and de novo when no suitable non-preference-based instrument exists, using IRT and Rasch analysis. For items that fit the Rasch model, developers selected one item per dimension and explored item response level reduction. This framework will guide researchers who are developing or assessing CSPBIs.

Psychometric Performance of Generic Childhood Multi-Attribute Utility Instruments in Preterm and Low Birthweight Populations: A Systematic Review

BACKGROUND

Individuals born preterm (gestational age < 37 weeks) and/or at low birthweight (<2500 g) are at increased risk of health impairments from birth to adulthood. This review aimed to evaluate the psychometric performance of generic childhood-specific or childhood-compatible multi-attribute utility instruments (MAUIs) in preterm and/or low birthweight (PLB) populations.

METHODS

Searches covered seven databases, including studies that targeted childhood (aged < 18 years) and/or adult (≥18 years) PLB populations; provided psychometric evidence for generic childhood-specific or compatible MAUI(s) (any language version); and published in English. Eighteen psychometric properties were evaluated using a four-part criteria rating system. Data syntheses identified psychometric evidence gaps and summarised the psychometric assessment methods/results.

RESULTS

A total of 42 studies were included, generating 178 criteria rating outputs across four MAUIs: 17D, CHSCS-PS, HUI2, and HUI3. Moreover, 64.0% of outputs concerned the HUI3 MAUI, and 38.2% related to known-group validity. There was no evidence for five psychometric properties. Only 6.7% of outputs concerned reliability and proxy-child agreement. No MAUI outperformed others across all properties. The frequently applied HUI2 and HUI3 lacked content validity evidence.

CONCLUSIONS

This psychometric evidence catalogue should inform the selection of MAUI(s) suited to the specific aims of applications targeting PLB populations. Further psychometric research is warranted to address the gaps in psychometric evidence.

Developing an Australian utility value set for the Early Childhood Oral Health Impact Scale-4D (ECOHIS-4D) using a discrete choice experiment

PURPOSE

Preference-based quality of life measures (PBMs) are used to generate quality-adjusted life years (QALYs) in economic evaluations. A PBM consists of (1) a health state classification system and (2) a utility value set that allows the instrument responses to be converted to QALYs. A new, oral health-specific classification system, the Early Childhood Oral Health Impact Scale-4D (ECOHIS-4D) has recently been developed. The aim of this study was to generate an Australian utility value set for the ECOHIS-4D.

METHODS

A discrete choice experiment with duration (DCETTO) was used as the preference elicitation technique. An online survey was administered to a representative sample of Australian adults over 18 years. Respondents were given 14 choice tasks (10 tasks from the DCE design of 50 choice sets blocked into five blocks, 2 practice tasks, a repeated and a dominant task). Data were analyzed using the conditional logit model.

RESULTS

A total of 1201 respondents from the Australian general population completed the survey. Of them, 69% (n = 829) perceived their oral health status to be good, very good, or excellent. The estimated coefficients from the conditional logit models were in the expected directions and were statistically significant (p < 0.001). The utility values for health states defined by the ECOHIS-4D ranged from 0.0376 to 1.0000.

CONCLUSIONS

This newly developed utility value set will enable the calculation of utility values for economic evaluations of interventions related to oral diseases such as dental caries among young children. This will facilitate more effective resource allocation for oral health services.

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

BACKGROUND

Discrete choice experiments (DCEs) are increasingly used in health state valuation studies.

OBJECTIVE

This systematic review updates the progress and new findings of DCE studies in the health state valuation, covering the period since the review of June 2018 to November 2022. The review reports the methods that are currently being used in DCE studies to value health and study design characteristics, and, for the first time, reviews DCE health state valuation studies published in the Chinese language.

METHODS

English language databases PubMed and Cochrane, and Chinese language databases Wanfang and CNKI were searched using the self-developed search terms. Health state valuation or methodology study papers were included if the study used DCE data to generate a value set for a preference-based measure. Key information extracted included DCE study design strategies applied, methods for anchoring the latent coefficient on to a 0-1 QALY scale and data analysis methods.

RESULTS

Sixty-five studies were included; one Chinese language publication and 64 English language publications. The number of health state valuation studies using DCE has rapidly increased in recent years and these have been conducted in more countries than prior to 2018. Wide usage of DCE with duration attributes, D-efficient design and models accounting for heterogeneity has continued in recent years. Although more methodological consensus has been found than in studies conducted prior to 2018, this consensus may be driven by valuation studies for common measures with an international protocol (the 'model' valuation research). Valuing long measures with well-being attributes attracted attention and more realistic design strategies (e.g., inconstant time preference, efficient design and implausible states design) were identified. However, more qualitative and quantitative methodology study is still necessary to evaluate the effect of those new methods.

CONCLUSIONS

The use of DCEs in health state valuation continues to grow dramatically and the methodology progress makes the method more reliable and pragmatic. However, study design is driven by international protocols and method selection is not always justified. There is no gold standard for DCE design, presentation format or anchoring method. More qualitative and quantitative methodology study is recommended to evaluate the effect of new methods before researchers make methodology decisions.

A Systematic Review of International Guidance for Self-Report and Proxy Completion of Child-Specific Utility Instruments

OBJECTIVES

This study aimed to identify and summarize published guidance and recommendations for child self- and proxy assessment of existing child-specific instruments of health-related quality of life (HRQoL) that are accompanied by utilities.

METHODS

A total of 9 databases plus websites of (1) health technology assessment and health economics outcomes research organizations and (2) instrument developers were systematically searched. Studies were included if they reported guidance for child self- and proxy assessment for child populations (0-18 years old). Three reviewers independently screened titles, abstracts, and full-text reviews against the inclusion criteria. Key features of the guidance identified were summarized.

RESULTS

A total of 19 studies met the inclusion criteria. In general, journal articles provided little guidance on child self- and proxy assessment, with the majority focused on instrument development and psychometric performance more broadly. Instrument developers' websites provided more guidance for child self- and proxy reports with specific guidance found for the EQ-5D-Y and the Pediatric Quality of Life Inventory. This guidance included the minimum age for self-report and mode of administration; recommended proxy types, age range of child for whom proxy report can be completed, and target population; and recall period. Websites of leading organizations provided general guidance on HRQoL evaluation in children but lacked specific guidance about self- and proxy completion.

CONCLUSIONS

EQ-5D-Y and Pediatric Quality of Life Inventory developers' websites provided the most comprehensive guidance for self-report and proxy report of their respective instruments. More evidence is required for developing best practice guidance on why, when, and how to use self- and proxy reports in assessing HRQoL in child populations.

Preference Elicitation Techniques Used in Valuing Children's Health-Related Quality-of-Life: A Systematic Review

BACKGROUND AND OBJECTIVES

Valuing children's health states for use in economic evaluations is globally relevant and is of particular relevance in jurisdictions where a cost-utility analysis is the preferred form of analysis for decision making. Despite this, the challenges with valuing child health mean that there are many remaining questions for debate about the approach to elicitation of values. The aim of this paper was to identify and describe the methods used to value children's health states and the specific issues that arise in the use of these methods.

METHODS

We conducted a systematic search of electronic databases to identify studies published in English since 1990 that used preference elicitation methods to value child and adolescent (under 18 years of age) health states. Eligibility criteria comprised valuation studies concerning both child-specific patient-reported outcome measures and child health states defined in other ways, and methodological studies of valuation approaches that may or may not have yielded a value set algorithm.

RESULTS

A total of 77 eligible studies were identified from which data on country setting, aims, condition (general population or clinically specific), sample size, age of respondents, the perspective that participants were asked to adopt, source of values (respondents who completed the preference elicitation tasks) and methods questions asked were extracted. Extracted data were classified and evaluated using narrative synthesis methods. The studies were classified into three groups: (1) studies comparing elicitation methods (n = 30); (2) studies comparing perspectives (n = 23); and (3) studies where no comparisons were presented (n = 26); selected studies could fall into more than one group. Overall, the studies varied considerably both in methods used and in reporting. The preference elicitation tasks included time trade-off, standard gamble, visual analogue scaling, rating/ranking, discrete choice experiments, best-worst scaling and willingness to pay elicited through a contingent valuation. Perspectives included adults' considering the health states from their own perspective, adults taking the perspective of a child (own, other, hypothetical) and a child/adolescent taking their own or the perspective of another child. There was some evidence that children gave lower values for comparable health states than did adults that adopted their own perspective or adult/parents that adopted the perspective of children.

CONCLUSIONS

Differences in reporting limited the conclusions that can be formed about which methods are most suitable for eliciting preferences for children's health and the influence of differing perspectives and values. Difficulties encountered in drawing conclusions from the data (such as lack of consensus and poor reporting making it difficult for users to choose and interpret available values) suggest that reporting guidelines are required to improve the consistency and quality of reporting of studies that value children's health using preference-based techniques.

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.

Comparing multi-attribute utility instruments: CP-6D, a Cerebral palsy specific instrument, vs AQoL-4D

Background: Economic-evaluations of Cerebral palsy (CP) were based on utility estimates of health-related quality of life (HRQoL) from generic multi-attribute utility instruments (MAUIs). However, generic instruments had limited use as they could not capture some of the important aspects of living with CP. The Cerebral palsy 6 Dimension (CP-6D) is a disease specific MAUI. In this study, we compared the results of CP-6D with the Assessment of Quality of Life (AQoL-4D), a generic MAUI, and tested the criterion validity of the CP-6D in the general population.Methods:An online survey of the Australian general population (n = 2002), who completed both the AQoL-4D and CP-6D MAUIs, was conducted. Validity was assessed from the correlations between the domains, items and instruments. ANOVA and t-tests were used to assess the instrument's discrimination in different social demographic categories.Results:There was a moderate correlation between the instruments (0.64). Differences in socio-demographic characteristics showed a medium effect size (p < 0.001) in both instruments and had a similar effect on utility weights in both instruments. Although the CP-6D was more sensitive to changes in income and education.Conclusions: Our results suggest that CP-6D and AQoL-4D were measuring a similar underlying construct. Both instruments responded similarly to socio-demographic differences.