Censoring Time Trade-off Values at 0 Versus at -1: How Does the Assumption for Worse-Than-Dead Time Trade-off Values Affect the Modeling of EQ-5D-5L Valuation Data?

Is anchoring at 'dead' a theoretical requirement for health state valuation?

Values that accompany generic health measures are typically anchored at 1 = full health and 0 = dead. Some health states may then be considered 'worse than dead' (WTD) and assigned negative values, which causes fundamental measurement problems. In this paper, we challenge the assumption that anchoring values at 'dead = 0' is necessary for quality-adjusted life year (QALY) estimation. We summarise the role of 'dead' in health state valuation and consider three critical questions: (i) whether the measurement properties of health state values require 'dead'; (ii) whether 'dead' needs to be valued relative to health states; and (iii) whether values for states WTD are meaningful or useful. We conclude that anchoring 0 at dead is not a requirement of health status measurement or cost-effectiveness analysis. This results from reframing QALYs as the relevant unit of measurement and reframing values as being derived from QALYs rather than the reverse.

Health-related quality of life in primary care patients: a comparison between EQ-5D-5L utility score and EQ-visual analogue scale

OBJECTIVE

The EQ-VAS is an important component of the EQ-5D questionnaire. However, there is limited evidence comparing its performance to the EQ-5D utility score, which restricts its use in the population. This study aimed to EQ-5D-5L utility score and EQ-visual analogue scale (EQ-VAS) in primary care patients in Hong Kong (HK).

METHODS

Secondary data analysis was performed on the data collected from a cross-sectional survey to investigate patient engagement in HK. Participants were recruited through random sampling from a single general outpatient clinic. Trained investigators conducted face-to-face interviews with all eligible patients attending the clinic. Patients who were: 1) ≥ 18 years old, 2) have visited the clinic at least once in the last 6 months, 3) no cognitive problems, and 4) can speak and understand the local language. Pearson correlation was used to explore the association between EQ-5D utility and EQ-VAS score. Ordinary least squares regression and heteroscedastic Tobit regression models were adopted to analyze the EQ-VAS and EQ-5D utility data, respectively.

RESULTS

The analysis included data from 1,004 responses (response rate = 65%). Around 52.7% of participants were female, 25.9% completed tertiary or above education, and 75.1% living with chronic disease. The mean EQ-5D utility and EQ-VAS score were 0.92 (SD = 0.13) and 72.27 (SD = 14.69), respectively. A significant association was found between EQ-5D utility and EQ-VAS score, with coefficients ranging from 0.335 (participants who divorced) to 0.744 (participants living alone). Around 98.5% reported having no problems with 'Self-care', followed by 'Usual activities' (96.3%), 'Mobility' (91.5%) and 'Anxiety/depression' (79.9%). The correlation between EQ-VAS score and EQ-5D utility was positive for each dimension of the EQ-5D instrument (correlation coefficients ranged between 0.211 and 0.623). Age strongly influenced the magnitude and trajectory of EQ-VAS score and utility, as observed in the changes. The regression model showed that 'Mobility', 'Pain/discomfort', and 'Anxiety/depression' have considerable influence on EQ-VAS score.

CONCLUSIONS

This study compared the EQ-5D utility score and EQ-VAS in HK primary care setting. Although heterogeneity existed, the EQ-VAS and utility score are significantly correlated and reliable for evaluating health-related quality of life in this population.

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.