Psychometric Performance of HRQoL Measures: An Australian Paediatric Multi-Instrument Comparison Study Protocol (P-MIC)

Rationale, conceptual issues, and resultant protocol for a mixed methods Person Trade Off (PTO) and qualitative study to estimate and understand the relative value of gains in health for children and young people compared to adults

BACKGROUND

Economic evaluation of healthcare typically assumes that an identical health gain to different patients has the same social value. There is some evidence that the public may give greater value to gains for children and young people, although this evidence is not always consistent. We present a mixed methods study protocol where we aim to explore public preferences regarding health gains to children and young people relative to adults, in an Australian setting.

METHODS

This study is a Person Trade Off (PTO) choice experiment that incorporates qualitative components. Within the PTO questions, respondents will be asked to choose between treating different groups of patients that may differ in terms of patient characteristics and group size. PTO questions will be included in an online survey to explore respondent views on the relative value of health gains to different age groups in terms of extending life and improving different aspects of quality of life. The survey will also contain attitudinal questions to help understand the impact of question style upon reported preferences. Additionally, the study will test the impact of forcing respondents to express a preference between two groups compared with allowing them to report that the two groups are equivalent. One-to-one 'think aloud', semi-structured interviews will be conducted to explore a sub-sample of respondents' motivations and views in more detail. Focus groups will be conducted with members of the public to discuss the study findings and explore their views on the role of public preferences in health care prioritisation based on patient age.

DISCUSSION

Our planned study will provide valuable information to healthcare decision makers in Australia who may need to decide whether to pay more for health gains for children and young people compared with adults. Additionally, the methodological test of forcing respondent choice or allowing them to express equivalence will contribute towards developing best practice methods in PTO studies. The rationale for and advantages of the study approach and potential limitations are discussed in the protocol.

A Comparison of the Psychometric Properties of the EQ-5D-Y-3L and EQ-5D-Y-5L Using Paediatric Multi-Instrument Comparison (P-MIC) Study Data

BACKGROUND

The EQ-5D-Y is a generic health-related quality of life (HRQoL) measure suitable for children and adolescents. There are two versions of the instrument, which differ in response levels: the three- (Y-3L) and five-level (Y-5L) versions. The Y-5L has been developed to improve the psychometric performance of the Y-3L.

OBJECTIVE

This study aims to assess the psychometric properties of Y-5L and to compare the performance of Y-5L with Y-3L in separate self- and proxy-reported samples.

METHODS

Both versions of the instrument were administered to children/adolescents (self-report) or caregivers (proxy-report) of Australian children aged 5-18 years. The data were gathered as part of the Australian Paediatric Multi-Instrument Comparison (P-MIC) study. The Y-5L and Y-3L were evaluated in terms of ceiling effects, criterion validity, inconsistency, informativity, and test-retest reliability in both proxy and self-complete populations.

RESULTS

Overall, 5945 respondents completed both the Y-3L and Y-5L, with 2083 proxy and 3862 self-completed responses. Ceiling effects were lower in the Y-5L than the Y-3L. Items from the same domains show the strongest correlation for both samples. Regarding informativity, the Y-5L demonstrated more discriminatory power, indicated by having a higher Shannon diversity index in all domains of the Y-5L compared with the Y-3L. Test-retest showed fair agreement between responses at baseline and follow-up.

CONCLUSION

The Y-5L has demonstrated moderate validity and fair reliability for use in measuring HRQoL in children and adolescents, both when self-reported by children or proxy reported. Overall, Y-5L is a dependable and valid extension from the Y-3L.

Psychometric Properties of Child Health Utility 9D (CHU9D) Proxy Version Administered to Parents and Caregivers of Children Aged 2-4 Years Compared with Pediatric Quality of Life Inventory™ (PedsQL)

OBJECTIVE

This study examines the psychometric properties of the Child Health Utility 9D (CHU9D) proxy version administered to parents/caregivers of 2-4-year-old Australian children compared with Pediatric Quality of Life Inventory™ version 4.0 (PedsQL).

METHODS

Data collected in 2021/2022 from parents/caregivers of 2-4-year-olds from the Australian pediatric multi-instrument comparison study were used. Feasibility, ceiling/floor effects, test-retest reliability, convergent validity, known-group validity, and responsiveness were assessed.

RESULTS

A total of 842 caregivers completed the survey at baseline, with 513 completing the follow-up survey. The CHU9D did not demonstrate ceiling effects in the sample with special health care needs, with only 6% of respondents reporting best levels for all nine dimensions. CHU9D correlated with PedsQL moderately-to-strongly between comparable items (correlation coefficients 0.34-0.70). CHU9D was able to differentiate between groups with known health differences with moderate-to-large effect sizes (Cohen's d 0.58-2.03). Moderate test-retest reliability was found for CHU9D in those reporting no health change at a 2-day follow-up (ICC 0.52). A standard response mean (SRM) of 0.25-0.44 was found for children with changes in general health and a SRM of 0.72-0.82 for children who reported worsened health when developing new illnesses, indicating small-to-large responsiveness according to different definitions of health changes. Compared with PedsQL, CHU9D had similar known-group validity and responsiveness and slightly poorer test-retest reliability.

CONCLUSION

The CHU9D was found to be valid and reliable to measure health-related quality-of-life in children aged 2-4 years, although with relatively low test-retest reliability in some dimensions. Further development and validation work is warranted.

Comparative Psychometric Performance of Common Generic Paediatric Health-Related Quality of Life Instrument Descriptive Systems: Results from the Australian Paediatric Multi-Instrument Comparison Study

OBJECTIVE

The aim of this study was to compare the psychometric performance of common generic paediatric health-related quality-of-life instrument descriptive systems (PedsQL generic core 4.0, EQ-5D-Y-3L, EQ-5D-Y-5L, Child Health Utility 9D [CHU9D], Assessment of Quality of Life 6D [AQoL-6D], and Health Utilities Index Mark 3 [HUI3]) by child age, report type, and health status.

METHODS

Data for children aged 5-18 years were from the Australian Paediatric Multi-Instrument Comparison study. Ceiling effects, test-retest reliability, known-group validity, convergent and divergent validity, and responsiveness were assessed in the total sample and by child age (5-12 years vs 13-18 years), report type (self- vs proxy report), and health status. Instruments were scored using an exploratory level sum score (LSS) approach.

RESULTS

Survey data were available for 5945 children, with follow-up data available for 2346 children. The EQ-5D-Y-3L demonstrated ceiling effects. The PedsQL, EQ-5D-Y-3L, EQ-5D-Y-5L, and CHU9D demonstrated acceptable test-retest reliability. All instruments demonstrated known-group, convergent, and divergent validity. The EQ-5D-Y-3L, EQ-5D-Y-5L, and CHU9D demonstrated responsiveness to improvements in health and the PedsQL, EQ-5D-Y-3L, EQ-5D-Y-5L, and CHU9D to worsening health. The AQoL-6D and HUI3 had inconclusive test-retest reliability and responsiveness evidence due to small sample size. Importantly, ceiling effects, test-retest reliability and responsiveness varied by subgroup.

CONCLUSION

Results reflect instrument performance using LSSs, which may differ to utility scores. In the total sample, the EQ-5D-Y-5L and CHU9D descriptive systems demonstrated evidence of good performance (i.e., meeting prespecified criteria) across all psychometric attributes tested. Performance varied by child age and report type, indicating room for considerations by population and study.

Psychometric Performance Comparison of the Adapted versus Original Versions of the EQ-5D-Y-3L and -Y-5L in Proxy Respondents for 2- to 4-Year-Olds

INTRODUCTION

Few preference-weighted instruments are available to measure health-related quality of life in young children (2-4 years of age). The EQ-5D-Y-3L and EQ-5D-Y-5L were recently modified for this purpose.

OBJECTIVE

The aim of this study was to test the psychometric properties of these adapted versions for use with parent proxies of children aged 2-4 years and to compare their performance with the original versions. It was hypothesised that the adapted instrument wording would result in improved psychometric performance.

METHODS

Survey data of children aged 2-4 years were obtained from the Australian Paediatric Multi-Instrument Comparison study. Distributional and psychometric properties tested included feasibility, convergence, distribution of level scores, ceiling effects, known-group validity (Cohen's D effect sizes for prespecified groups defined by the presence/absence of special healthcare needs [SHCNs]), test-retest reliability (intraclass correlation coefficients [ICCs]), and responsiveness (standardised response mean [SRM] effect sizes for changes in health). Level sum scores were used to provide summary outcomes. Supplementary analysis using utility scores (from the Swedish EQ-5D-Y-3L value set) were conducted for the adapted and original EQ-5D-Y-3L, and no value sets were available for the EQ-5D-Y-5L.

RESULTS

A total of 842 parents of children aged 2-4 years completed the survey. All instruments were easy to complete. There was strong convergence between the adapted and original EQ-5D-Y-3L and EQ-5D-Y-5L. The adapted EQ-5D-Y-3L and adapted EQ-5D-Y-5L showed more responses in the severe levels of the five EQ-5D-Y dimensions, particularly in the usual activity and mobility dimensions (EQ-5D-Y-5L: mobility level 1: adapted n = 478 [83%], original n = 253 [94%]; mobility level 4/5: adapted n = 17 [2.9%], original n = 4 [1.5%)]). The difference in the distribution of responses was more evident in children with SHCNs. Assessment of known-group validity showed a greater effect size for the adapted EQ-5D-Y-3L and adapted EQ-5D-Y-5L compared with the original instruments (EQ-5D-Y-5L: adapted Cohen's D = 1.01, original Cohen's D = 0.83) between children with and without SHCNs. The adapted EQ-5D-Y-3L and adapted EQ-5D-Y-5L showed improved reliability at 4-week follow-up, with improved ICCs (EQ-5D-Y-5L: adapted ICC = 0.83, original ICC = 0.44). The responsiveness of all instruments moved in the hypothesised direction for better or worse health at follow-up. Probability of superiority analysis showed little/no differences between the adapted and original EQ-5D-Y-3L and EQ-5D-Y-5L. Supplementary psychometric analysis of the adapted and original EQ-5D-Y-3L using utilities showed comparable findings with analyses using level sum scores.

CONCLUSIONS

The findings suggest improved psychometric performance of the adapted version of the EQ-5D-Y-3L and EQ-5D-Y-5L in children aged 2-4 years compared with the original versions.

Comparing Generic Paediatric Health-Related Quality-of-Life Instruments: A Dimensionality Assessment Using Factor Analysis

BACKGROUND

Widely used generic instruments to measure paediatric health-related quality of life (HRQoL) include the EQ-5D-Y-5L, Child Health Utility 9 Dimension (CHU-9D), Paediatric Quality of Life Inventory (PedsQL) and Health Utilities Index (HUI). There are similarities and differences in the content of these instruments, but there is little empirical evidence on how the items they contain relate to each other, and to an overarching model of HRQoL derived from their content.

OBJECTIVE

This study aimed to explore the dimensionality of the instruments using exploratory factor analysis (EFA).

METHODS

Data from the Australian Paediatric Multi-Instrument Comparison (P-MIC) Study were used. EQ-5D-Y-5L, CHU-9D, PedsQL and HUI data were collected via proxy or child self-report data. EFA was used to investigate the underlying domain structure and measurement relationship. Items from the four instruments were pooled and domain models were identified for self- and proxy-reported data. The number of factors was determined based on eigenvalues greater than 1. A correlation cut-off of 0.32 was used to determine item loading on a given factor, with cross-loading also considered. Oblique rotation was used.

RESULTS

Results suggest a six-factor structure for the proxy-reported data, including emotional functioning, pain, daily activities, physical functioning, school functioning, and senses, while the self-report data revealed a similar seven-factor structure, with social functioning emerging as an additional factor.

CONCLUSION

We provide evidence of differences and similarities between paediatric HRQoL instruments and the aspects of health being measured by these instruments. The results identified slight differences between self- and proxy-reported data in the relationships among items within the resulting domains.

Comparing the Psychometric Performance of Generic Paediatric Health-Related Quality of Life Instruments in Children and Adolescents with ADHD, Anxiety and/or Depression

OBJECTIVE

The aim of this study was to examine the validity, reliability and responsiveness of common generic paediatric health-related quality of life (HRQoL) instruments in children and adolescents with mental health challenges.

METHODS

Participants were a subset of the Australian Paediatric Multi-Instrument Comparison (P-MIC) study and comprised 1013 children aged 4-18 years with attention-deficit/hyperactivity disorder (ADHD) (n = 533), or anxiety and/or depression (n = 480). Participants completed an online survey including a range of generic paediatric HRQoL instruments (PedsQL, EQ-5D-Y-3L, EQ-5D-Y-5L, CHU9D) and mental health symptom measures (SDQ, SWAN, RCADS-25). A subset of participants also completed the HUI3 and AQoL-6D. The psychometric performance of each HRQoL instrument was assessed regarding acceptability/feasibility; floor/ceiling effects; convergent validity; known-group validity; responsiveness and test-retest reliability.

RESULTS

The PedsQL, CHU9D, EQ-5D-Y-3L and EQ-5D-Y-5L showed similarly good performance for acceptability/feasibility, known-group validity and convergent validity. The CHU9D and PedsQL showed no floor or ceiling effects and fair-good test-retest reliability. Test-retest reliability was lower for the EQ-5D-Y-3L and EQ-5D-Y-5L. The EQ-5D-Y-3L showed the highest ceiling effects, but was the top performing instrument alongside the CHU9D on responsiveness to improvements in health status, followed by the PedsQL. The AQoL-6D and HUI3 showed good acceptability/feasibility, no floor or ceiling effects, and good convergent validity, yet poorer performance on known-group validity. Responsiveness and test-retest reliability were not able to be assessed for these two instruments. In subgroup analyses, performance was similar for all instruments for acceptability/feasibility, known-group and convergent validity, however, relative strengths and weaknesses for each instrument were noted for ceiling effects, responsiveness and test-retest reliability. In sensitivity analyses using utility scores, performance regarding known-group and convergent validity worsened slightly for the EQ-5D-Y-3L and CHU9D, though improved slightly for the HUI3 and AQoL-6D.

CONCLUSIONS

While each instrument showed strong performance in some areas, careful consideration of the choice of instrument is advised, as this may differ dependent on the intended use of the instrument, and the age, gender and type of mental health condition of the population in which the instrument is being used.

TRIAL REGISTRATION

ANZCTR-ACTRN12621000657820.

The Validity of the EuroQol Health and Wellbeing Short Version (EQ-HWB-S) Instrument in Parents of Children With and Without Health Conditions

BACKGROUND

 The EuroQol Health and Wellbeing Short Version (EQ-HWB-S) instrument has been developed to measure the health and wellbeing of care-recipients and their caregivers for use in economic evaluation.The EQ-HWB-S has nine items, and pilot UK preference weights have now been developed.

OBJECTIVE

We aimed to investigate the validity of the instrument in parents of children with and without health conditions.

METHODS

EQ-HWB-S data were sourced from an Australian paediatric multi-instrument comparison study. We analysed the baseline characteristics and response distribution of the EQ-HWB-S items. Assessment of known-group validity was conducted for EQ-HWB-S items, level sum-scores and preference-weighted scores, including partial effects. Known-group analyses included three child health variables and where caregivers reported coronavirus disease 2019 (COVID-19) had impacted their wellbeing. We included analyses across gender, controlled for child and parent demographic variables, and compared scores across child health conditions.

RESULTS

 Item responses were distributed as expected, with higher skew for mobility and activities. Parents experienced high levels of exhaustion. We detected significant differences between groups for level sum-scores and preference-weighted scores, as hypothesised; all tests were significant (p < 0.001), with moderate effect sizes (effect sizes were slightly higher for female than male parents). The regression analysis identified significantly different EQ-HWB-S scores for child health samples compared with the general population after controlling for demographic variables. Differences were observed between child health conditions.

CONCLUSION

The EQ-HWB-S is a useful instrument to measure parent quality of life for economic evaluation in this population. Data were limited to one time point; further research should investigate the instrument's sensitivity to change and test-retest reliability in this population.

Collecting Paediatric Health-Related Quality of Life Data: Assessing the Feasibility and Acceptability of the Australian Paediatric Multi-Instrument Comparison (P-MIC) Study

BACKGROUND

Collecting data using paediatric health-related quality of life (HRQoL) instruments is complex, and there is a paucity of evidence regarding the comparative performance of paediatric HRQoL instruments. The Australian Paediatric Multi-Instrument Comparison (P-MIC) study was conducted to address this paucity of evidence. This study aims to understand the (1) feasibility of collecting data using paediatric HRQoL instruments in a research setting and (2) acceptability and feasibility for children and their caregivers to complete common paediatric HRQoL instruments using data from the Australian P-MIC study.

METHODS

Data were from children aged 5-18 years from the Australian P-MIC study. Demographics, cost and time for data collection, dropout rates, and inconsistent responses were used to assess Aim 1. Participant-reported difficulty and completion time were used to assess Aim 2. Subgroup analyses included child age, report type (self/proxy), sample recruitment pathway (hospital/online), and online panel sample type (general population/condition groups).

RESULTS

Overall, 5945 P-MIC participants aged 5-18 years completed an initial survey, of these, 2346 also completed the follow-up survey (39.5% response rate). Compared with online panel recruitment, hospital recruitment was more costly and time-consuming and had higher follow-up completion (33.5% versus 80.4%) (Aim 1). Data were of similar good quality (based on inconsistent responses) for both recruitment pathways (Aim 1). Participants completed each instrument in <3 min, on average, and >70% reported each instrument as easy to complete (Aim 2).

CONCLUSIONS

The Australian P-MIC study was able to collect good-quality data using both online panel and hospital recruitment pathways. All instruments were acceptable and feasible to children and their caregivers.

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.

Assessing Value in Child Health

Assessing value in child health is increasingly important as health care systems face difficult choices with regard to what services and programs for children to fund and deliver [...]