The estimation of a preference-based measure of health from the SF-36

This paper reports on the findings of a study to derive a preference-based measure of health from the SF-36 for use in economic evaluation. The SF-36 was revised into a six-dimensional health state classification called the SF-6D. A sample of 249 states defined by the SF-6D have been valued by a representative sample of 611 members of the UK general population, using standard gamble. Models are estimated for predicting health state valuations for all 18,000 states defined by the SF-6D. The econometric modelling had to cope with the hierarchical nature of the data and its skewed distribution. The recommended models have produced significant coefficients for levels of the SF-6D, which are robust across model specification. However, there are concerns with some inconsistent estimates and over prediction of the value of the poorest health states. These problems must be weighed against the rich descriptive ability of the SF-6D, and the potential application of these models to existing and future SF-36 data set

Accounts from developers of generic health state utility instruments explain why they produce different QALYs: a qualitative study

Purpose and setting: Despite the label generic health state utility instruments (HSUIs), empirical evidence shows that different HSUIs generate different estimates of Health-Related Quality of Life (HRQoL) in the same person. Once a HSUI is used to generate a QALY, the difference between HSUIs is often ignored, and decision-makers act as if \u27a QALY is a QALY is a QALY\u27. Complementing evidence that different generic HSUIs produce different empirical values, this study addresses an important gap by exploring how HSUIs differ, and processes that produced this difference. 15 developers of six generic HSUIs used for estimating the QOL component of QALYs: Quality of Well-Being (QWB) scale; 15 Dimension instrument (15D); Health Utilities Index (HUI); EuroQol EQ-5D; Short Form-6 Dimension (SF-6D), and the Assessment of Quality of Life (AQoL) were interviewed in 2012-2013. Principal findings: We identified key factors involved in shaping each instrument, and the rationale for similarities and differences across measures. While HSUIs have a common purpose, they are distinctly discrete constructs. Developers recalled complex developmental processes, grounded in unique histories, and these backgrounds help to explain different pathways taken at key decision points during the HSUI development. The basis for the HSUIs was commonly not equivalent conceptually: differently valued concepts and goals drove instrument design and development, according to each HSUI\u27s defined purpose. Developers drew from different sources of knowledge to develop their measure depending on their conceptualisation of HRQoL. Major conclusions/contribution to knowledge: We generated and analysed first-hand accounts of the development of the HSUIs to provide insight, beyond face value, about how and why such instruments differ. Findings enhance our understanding of why the six instruments developed the way they did, from the perspective of key developers of those instruments. Importantly, we provide additional, original explanation for why a QALY is not a QALY is not a QALY

Destruction of density-wave states by a pseudo-gap in high magnetic fields: application to (TMTSF)2_2ClO4_4

A model is presented for the destruction of density-wave states in quasi-one-dimensional crystals by high magnetic fields. The model is consistent with previously unexplained properties of the organic conductors (TMTSF)$_2$ClO$_4$ and (BEDT-TTF)$_2$MHg(SCN)$_4$ (M=K,Rb,Tl). As the magnetic field increases quasi-one-dimensional density-wave fluctuations increase, producing a pseudo-gap in the electronic density of states near the transition temperature. When the pseudo-gap becomes larger than the mean-field transition temperature formation of a density-wave state is not possible.Comment: 4 pages, RevTeX, 2 figures in uuencoded compressed tar file. Small changes to text and Figure 1. Final version to appear in Physical Review Letter

How do Zimbabweans value health states?

Background Quality of life weights based on valuations of health states are often used in cost utility analysis and population health measures. This paper reports on an attempt to develop quality of life weights within the Zimbabwe context. Methods 2,384 residents in randomly selected small residential plots of land in a high-density suburb of Harare valued descriptors of 38 health states based on different combinations of the five domains of the EQ-5D (mobility, self-care, usual activities, pain or discomfort and anxiety or depression). The English version of the EQ-5D was used. The time trade-off method was used to determine the values, and 19,020 individual preferences for health states were analysed. A residual maximum likelihood linear mixed model was used to estimate a function for predicting the values of all possible combinations of levels on the five domains. The model was fit to a random subset of two-thirds of the observations, with the remaining observations reserved for analysis of predictive validity. The results were compared to a similar study undertaken in the United Kingdom. Results A credible model was developed to predict the values of states that were not valued directly. In the subset of observations reserved for validation, the mean absolute difference between predicted and observed values was 0.045. All domains of the EQ-5D were found to contribute significantly to the model, both at the moderate and severe levels. Severe pain was found to have the largest negative coefficient, followed by the inability to wash and dress oneself. Conclusion Despite a generally lower education level than their European counterparts, urban Zimbabweans appear to value health states in a consistent manner, and the determination of a global method of establishing quality of life weights may be feasible and valid. However, as the relative weightings of the different domains, although correlated, differed from the standard set of weights recommended by the EuroQol Group, the locally determined coefficients should be used within the Zimbabwean context

An assessment of validity and responsiveness of generic measures of health-related quality of life in hearing impairment

This article is made available through the Brunel Open Access Publishing Fund. This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.Purpose: This review examines psychometric performance of three widely used generic preference-based measures, that is, EuroQol 5 dimensions (EQ-5D), Health Utility Index 3 (HUI3) and Short-form 6 dimensions (SF-6D) in patients with hearing impairments. Methods: A systematic search was undertaken to identify studies of patients with hearing impairments where health state utility values were measured and reported. Data were extracted and analysed to assess the reliability, validity (known group differences and convergent validity) and responsiveness of the measures across hearing impairments. Results: Fourteen studies (18 papers) were included in the review. HUI3 was the most commonly used utility measures in hearing impairment. In all six studies, the HUI3 detected difference between groups defined by the severity of impairment, and four out of five studies detected statistically significant changes as a result of intervention. The only study available suggested that EQ-5D only had weak ability to discriminate difference between severity groups, and in four out of five studies, EQ-5D failed to detected changes. Only one study involved the SF-6D; thus, the information is too limited to conclude on its performance. Also evidence for the reliability of these measures was not found. Conclusion: Overall, the validity and responsiveness of the HUI3 in hearing impairment was good. The responsiveness of EQ-5D was relatively poor and weak validity was suggested by limited evidence. The evidence on SF-6D was too limited to make any judgment. More head-to-head comparisons of these and other preference measures of health are required.Medical Research Counci

Qualidade de vida em doentes com asma

In this paper we present a study whose main aim is the measurement of the Health Related Quality of Life (HRQoL) of patients with asthma and the presentation of a first draft of normative values as measured by the SF-6D for asthma patients. In addition, we investigate how far non-disease-specific HRQoL measures can distinguish groups in terms of socio-demographic characteristics. The Portuguese versions of the EQ-5D, SF-6D, AQLQ(S) and ACQ were administered using personal interviews to a representative sample of the Portuguese population with asthma. Most of the individuals did not report significant problems in the dimensions used, with the exception of the physical functioning, where individuals reported moderate limitations. The mean utility value was 0.86. Male gender, young, single, individuals with high educational attainment level, employed, individuals with high income and those residing in urban areas reported higher utility levels. As expected, those who were in a severe stadium of the disease reported lower mean utility levels than those who were in a less severe stadium of the disease. Normative values for the SF-6D were computed for patients with asthma by gender, age, marital status, educational attainment level, employment status, area of residence and average monthly net income. The preference-based measures used in this study distinguish patient groups with asthma in terms of socio-demographic groups. The normative values can be used in economic evaluation and clinical studies as they incorporate patients' preferences and translate the value attributed to patients' health state.Foundation for Science and Technology [SFRH/BD/25697/2005]info:eu-repo/semantics/publishedVersio

Outcome Measurement in Economic Evaluations of Public Health Interventions: a Role for the Capability Approach?

Public health interventions have received increased attention from policy makers, and there has been a corresponding increase in the number of economic evaluations within the domain of public health. However, methods to evaluate public health interventions are less well established than those for medical interventions. Focusing on health as an outcome measure is likely to underestimate the impact of many public health interventions. This paper provides a review of outcome measures in public health; and describes the benefits of using the capability approach as a means to developing an all encompassing outcome measure

Population health status of South Asian and African-Caribbean communities in the United Kingdom

Population health status scores are routinely used to inform economic evaluation and evaluate the impact of disease and/or treatment on health. It is unclear whether the health status in black and minority ethnic groups are comparable to these population health status data. The aim of this study was to evaluate health-status in South Asian and African-Caribbean populations

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.UID/MULTI/4066/2016info:eu-repo/semantics/publishedVersio