What is it going to be, TTO or SG? A direct test of the validity of health state valuation

Reevaluating health metrics: Unraveling the limitations of disability-adjusted life years as an indicator in disease burden assessment

In 1993, the World Bank released a global report on the efficacy of health promotion, introducing the disability-adjusted life years (DALY) as a novel indicator. The DALY, a composite metric incorporating temporal and qualitative data, is grounded in preferences regarding disability status. This review delineates the algorithm used to calculate the value of the proposed DALY synthetic indicator and elucidates key methodological challenges associated with its application. In contrast to the quality-adjusted life years approach, derived from multi-attribute utility theory, the DALY stands as an independent synthetic indicator that adopts the assumptions of the Time Trade Off utility technique to define Disability Weights. Claiming to rely on no mathematical or economic theory, DALY users appear to have exempted themselves from verifying whether this indicator meets the classical properties required of all indicators, notably content validity, reliability, specificity, and sensitivity. The DALY concept emerged primarily to facilitate comparisons of the health impacts of various diseases globally within the framework of the Global Burden of Disease initiative, leading to numerous publications in international literature. Despite widespread adoption, the DALY synthetic indicator has prompted significant methodological concerns since its inception, manifesting in inconsistent and non-reproducible results. Given the substantial diffusion of the DALY indicator and its critical role in health impact assessments, a reassessment is warranted. This reconsideration is imperative for enhancing the robustness and reliability of public health decision-making processes.

Cataloging health state utility estimates for Duchenne muscular dystrophy and related conditions

BACKGROUND

Duchenne muscular dystrophy (DMD) is a genetic disease resulting in progressive muscle weakness, loss of ambulation, and cardiorespiratory complications. Direct estimation of health-related quality of life for patients with DMD is challenging, highlighting the need for proxy measures. This study aims to catalog and compare existing published health state utility estimates for DMD and related conditions.

METHODS

Using two search strategies, relevant utilities were extracted from the Tufts Cost-Effectiveness Analysis Registry, including health states, utility estimates, and study and patient characteristics. Analysis One identified health states with comparable utility estimates to a set of published US patient population utility estimates for DMD. A minimal clinically important difference of ± 0.03 was applied to each DMD utility estimate to establish a range, and the registry was searched to identify other health states with associated utilities that fell within each range. Analysis Two used pre-defined search terms to identify health states clinically similar to DMD. Mapping was based on the degree of clinical similarity.

RESULTS

Analysis One identified 4,308 unique utilities across 2,322 cost-effectiveness publications. The health states captured a wide range of acute and chronic conditions; 34% of utility records were extrapolated for US populations (n = 1,451); 1% were related to pediatric populations (n = 61). Analysis Two identified 153 utilities with health states clinically similar to DMD. The median utility estimates varied among identified health states. Health states similar to the early non-ambulatory DMD phase exhibited the greatest difference between the median estimate of the sample (0.39) and the existing estimate from published literature (0.21).

CONCLUSIONS

When available estimates are limited, using novel search strategies to identify utilities of clinically similar conditions could be an approach for overcoming the information gap. However, it requires careful evaluation of the utility instruments, tariffs, and raters (proxy or self).

Health state utility values in patients with Ankylosing Spondylitis: a systematic review and meta-analysis

INTRODUCTION

Ankylosing spondylitis (AS) is a chronic condition that requires lifelong treatment and results in a serious disease burden. Health state utility values (HSUVs) are a valuable tool for quantifying this burden and conducting cost-utility analysis.

OBJECTIVE

We conducted a systematic review and meta-analysis to obtain estimates of HSUVs in patients with AS, explored potential sources of heterogeneity, and compared pooled patient HSUVs with population norms.

METHOD

We searched PubMed, Embase, Web of science, Cochrane database and Scopus until July, 2023 to obtain eligible studies. The methodological quality of the included studies was assessed using the ROBINS-I checklist.

RESULTS

Forty-two publications involving 11,354 participants were included in this systematic review. The most commonly used instrument is the EQ-5D (38 studies). The estimated HSUVs for patients with AS from all available studies was pooled as 0.62 (95% CI 0.59 to 0.65). The pooled mean utility estimates from the random effects meta-analysis for SF-6D, EQ-5D-3L, EQ-5D-5L, and HUI3 were 0.65 (95% CI 0.62,0.68), 0.63 (95% CI 0.59,0.66), 0.60 (95% CI 0.42,0.79), and 0.48 (95% CI 0.43,0.53), respectively. For the EQ-5D-3L we conducted stratified meta-analyses and meta-regression based on key subgroups. The pooled estimates of EQ-5D-3L were lower for patients published before 2010, with high disease activity, long duration of disease, and in developed countries.

CONCLUSION

Pooled estimates of HSUVs for people with AS were substantially lower than population norms. These estimates provide robust evidence that can inform the economic evaluation of new therapies for individuals with AS.

Health Utility Score in Thai Patients with Chronic Rhinosinusitis: Pre- and Postoperative Analyses

BACKGROUND

Endoscopic sinus surgery (ESS) can increase the health utility score (HUS) of patients with chronic rhinosinusitis (CRS) who require the surgery. HUS varies depending on the geographical or living environment. HUS in CRS has never been evaluated in Thailand. The objective of this study was to evaluate the HUS of Thai patients with CRS before and after ESS through multiple approaches.

METHODS

Thai patients (age ≥ 18) with CRS scheduled for ESS were enrolled in this prospective study. The preoperative (baseline) demographics, 22-items sinonasal outcome test, endoscopic score, and CT score were recorded. The HUS was evaluated using four methods: the EuroQoL-5 Dimension-5 level (EQ-5D-5L), Visual Analog Scale (VAS), Standard gamble (SG), and Time trade-off (TTO); at baseline, three months and six months post-operation.

RESULTS

Data from 60 patients were analyzed. The mean baseline HUS scores by EQ-5D-5L, VAS, SG, and TTO were 0.75, 0.65, 0.79, and 0.85, respectively. The postoperative HUS significantly improved to 0.96, 0.91, 0.96, 0.97 at three months, and 0.97, 0.92, 0.97, and 0.98 at six months, respectively. ESS raised the HUS by 0.12-0.27 points. Among the four methods, VAS showed the lowest HUS at all time points.

CONCLUSION

The preoperative HUS in Thai patients with CRS generally increased to near-perfect values after the ESS. The increase in HUS reflecting the improved general quality of life, was demonstrated at three and up to six months after ESS.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:2070-2076, 2024.

Testing Nonmonotonicity in Health Preferences

OBJECTIVE

The main aim of this article is to test monotonicity in life duration. Previous findings suggest that, for poor health states, longer durations are preferred to shorter durations up to some threshold or maximum endurable time (MET), and shorter durations are preferred to longer ones after that threshold.

METHODS

Monotonicity in duration is tested through 2 ordinal tasks: choices and rankings. A convenience sample (n = 90) was recruited in a series of experimental sessions in which participants had to rank-order health episodes and to choose between them, presented in pairs. Health episodes result from the combination of 7 EQ-5D-3L health states and 5 durations. Monotonicity is tested comparing the percentage rate of participants whose preferences were monotonic with the percentage of participants with nonmonotonic preferences for each health state. In addition, to test the existence of preference reversals, we analyze the fraction of people who switch their preference from rankings to choices.

RESULTS

Monotonicity is frequently violated across the 7 EQ-5D health states. Preference patterns for individuals describe violations ranging from almost 49% with choices to about 71% with rankings. Analysis performed by separate states shows that the mean rates of violations with choices and ranking are about 22% and 34%, respectively. We also find new evidence of preference reversals and some evidence-though scarce-of transitivity violations in choices.

CONCLUSIONS

Our results show that there is a medium range of health states for which preferences are nonmonotonic. These findings support previous evidence on MET preferences and introduce a new "choice-ranking" preference reversal. It seems that the use of 2 tasks with a similar response scale may make preference reversals less substantial, although it remains important and systematic.

HIGHLIGHTS

Two procedures based on ordinal comparisons are used to elicit preferences: direct choices and rankings. Our study reports significant rates of nonmonotonic preferences (or maximum endurable time [MET]-type preferences) for different combinations of durations and EQ-5D health states.Analysis for separate health states shows that the mean rates of nonmonotonicity range from 22% (choices) to 34% (rankings), but within-subject analysis shows that nonmonotonicity is even higher, ranging from 49% (choices) to 71% (rankings). These violations challenge the validity of multiplicative QALY models.We find that the MET phenomenon may affect particularly those EQ-5D health states that are in the middle of the severity scale and not so much the extreme health states (i.e., very mild and very severe states).We find new evidence of preference reversals even using 2 procedures of a similar (ordinal) nature. Percentage rates of preference reversals range from 1.5% to 33%. We also find some (although scarce) evidence on violations of transitivity.

Time trade-off health state utility values for depression: a systematic review and meta-analysis

PURPOSE

This study aims to systematically review the literature on health utility in depression generated by time trade-off (TTO) method and to compare health state vignettes.

METHODS

Systematic literature search was conducted following PRISMA guideline in 2020 November (updated in 2022 March) in Pubmed, Web of Science, PsycInfo, and Cochrane Database of Systematic Reviews. Random effect meta-analysis was conducted to pool vignette-based utility values of mild, moderate, and severe depression and to compare the preferences of depressed and nondepressed population.

RESULTS

Overall, 264 records were found, 143 screened by title and abstract after removing duplicates, 18 assessed full text, and 14 original publications included. Majority of the studies (n = 9) used conventional TTO method, and most of the studies (n = 8) applied 10-year timeframe. Eight studies evaluated self-experienced health (own-current depression). Six studies assessed vignette-based health states of remitted, mild, moderate, and severe depression, half of them applied McSad measure based health description. Altogether, 61 different utility values have been cataloged, mean utility of self-experienced depression states (n = 33) ranged between 0.89 (current-own depression) and 0.24 (worst experienced depression). Pooled utility estimates for vignette-based mild, moderate, and severe depression was 0.75, 0.66 and 0.50, respectively. Meta-regression showed that severe depression (β = -0.16) and depressed sample populations (β =  -0.13) significantly decrease vignette-based utility scores.

CONCLUSION

Our review revealed extent heterogeneity both in TTO methodology and health state vignette development. Patient's perception of depression health states was worse than healthy respondents.

Analytical Considerations When Anchoring Discrete Choice Experiment Values Using Composite Time Trade-Off Data: The Case of EQ-5D-Y-3L

Discrete choice experiments (DCEs) are becoming increasingly used to elicit preferences for children's health states. However, DCE data need to be anchored to produce value sets, and composite time trade-off (cTTO) data are typically used in the context of EQ-5D-Y-3L valuation. The objective of this paper is to compare different anchoring methods, summarise the characteristics of the value sets they produce, and outline key considerations for analysts. Three anchoring methods were compared using data from published studies: (1) rescaling using the mean value for the worst health state; (2) linear mapping; and (3) hybrid modelling. The worst state rescaling value set had the largest range. The worst state rescaling and linear mapping value sets preserved the relative importance of the dimensions from the DCE, whereas the hybrid model value set did not. Overall, the predicted values from the hybrid model value set were more closely aligned with the cTTO values. These findings are relatively generalisable. Deciding upon which anchoring approach to use is challenging, as there are numerous considerations. Where cTTO data are collected for more than one health state, anchoring on the worst health state will arguably be suboptimal. However, the final choice of approach may require value judgements to be made. Researchers should seek input from relevant stakeholders when commencing valuation studies to help guide decisions and should clearly set out their rationale for their preferred anchoring approach in study outputs.

Correcting for discounting and loss aversion in composite time trade-off

Time trade-off utilities have been suggested to be biased upwards. This bias is a result of the method being applied assuming linear utility of life duration, which is violated when individuals discount future life years or are loss averse for health. Applying a "corrective approach", that is, measuring individuals' discount function and loss aversion and correcting time trade-off utilities for these individual characteristics, may reduce this bias in utilities. Earlier work has developed this approach for time trade-off in a student sample. In this study, the corrective approach was extended to composite time trade-off (cTTO) methodology, which enabled correcting utilities for health states worse than dead. In digital interviews a sample of 150 members of the general public completed cTTO tasks for six health states, and afterward they completed measurements of loss aversion and discounting. cTTO utilities were corrected using these measurements under multiple specifications. Respondents were also asked to reflect on and adjust their cTTO utilities directly. Our results show considerable loss aversion and both positive and negative discounting were prevalent. As predicted, correction generally resulted in lower utilities. This was in accordance with the direction of adjustments made by respondents themselves.

The Online Elicitation of Personal Utility Functions (OPUF) tool: a new method for valuing health states

Introduction Standard valuation methods, such as TTO and DCE are inefficient. They require data from hundreds if not thousands of participants to generate value sets. Here, we present the Online elicitation of Personal Utility Functions (OPUF) tool; a new type of online survey for valuing EQ-5D-5L health states using more efficient, compositional elicitation methods, which even allow estimating value sets on the individual level. The aims of this study are to report on the development of the tool, and to test the feasibility of using it to obtain individual-level value sets for the EQ-5D-5L. Methods We applied an iterative design approach to adapt the PUF method, previously developed by Devlin et al., for use as a standalone online tool. Five rounds of qualitative interviews, and one quantitative pre-pilot were conducted to get feedback on the different tasks. After each round, the tool was refined and re-evaluated. The final version was piloted in a sample of 50 participants from the UK. A demo of the EQ-5D-5L OPUF survey is available at: https://eq5d5l.me Results On average, it took participants about seven minutes to complete the OPUF Tool. Based on the responses, we were able to construct a personal EQ-5D-5L value set for each of the 50 participants. These value sets predicted a participants' choices in a discrete choice experiment with an accuracy of 80%. Overall, the results revealed that health state preferences vary considerably on the individual-level. Nevertheless, we were able to estimate a group-level value set for all 50 participants with reasonable precision. Discussion We successfully piloted the OPUF Tool and showed that it can be used to derive a group-level as well as personal value sets for the EQ-5D-5L. Although the development of the online tool is still in an early stage, there are multiple potential avenues for further research.

Expect Nothing: The (Lack of) Influence of Subjective Life Expectancy on Valuation of Child Health States

Objective

Earlier research has shown that individuals' subjective life expectancy (SLE) affects health state valuation with time trade-off (TTO). Individuals with longer expected life durations are less willing to trade-off life duration, which yields higher utilities. In this article, the influence of SLE is explored in the valuation of EQ-5D-Y-3L with a proxy perspective, i.e., adults' valuation of health states considering the life of a 10-year-old child. As SLE for children is likely higher, this might explain earlier findings suggesting that individuals are less willing to trade-off years of life for children than for adults.

Methods

A total of 197 respondents were recruited to take part in digital TTO interviews, facilitated by trained interviewers. TTO interviews were implemented in accordance with the recommended protocol for the valuation of EQ-5D-Y-3L. Respondents valued 10 EQ-5D-Y-3L health states for a 10-year-old child, after which they were asked to report how old they themselves expected to become and also how old they expected a 10-year-old child to become.

Results

Generally, adult respondents reported higher SLE for children than for themselves. Neither SLE was systematically associated with the willingness to trade lifetime or the number of life years traded off in TTO tasks. This null-result was substantiated by regression analyses per health state.

Conclusion

The results of this study suggest that individuals' expectations about longevity are not associated with EQ-5D-Y-3L valuation. This lack of association is in contrast to earlier work and might be explained by the psychological distance introduced with proxy perspective valuation, or by the methodological differences with earlier work.

Health-Related Quality of Life Measurement in Public Health

Patient-reported outcomes are recognized as essential for the evaluation of medical and public health interventions. Over the last 50 years, health-related quality of life (HRQoL) research has grown exponentially from 0 to more than 17,000 papers published annually. We provide an overview of generic HRQoL measures used widely in epidemiological studies, health services research, population studies, and randomized clinical trials [e.g., Medical Outcomes Study SF-36 and the Patient-Reported Outcomes Measurement Information System (PROMIS^®)-29]. In addition, we review methods used for economic analysis and calculation of the quality-adjusted life year (QALY). These include the EQ-5D, the Health Utilities Index (HUI), the self-administered Quality of Well-being Scale (QWB-SA), and the Health and Activities Limitation Index (HALex). Furthermore, we consider hybrid measures such as the SF-6D and the PROMIS-Preference (PROPr). The plethora of HRQoL measures has impeded cumulative science because incomparable measures have been used in different studies. Linking among different measures and consensus on standard HRQoL measurement should now be prioritized. In addition, enabling widespread access to common measures is necessary to accelerate future progress. Expected final online publication date for the Annual Review of Public Health, Volume 43 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Impact of Including Carer Information in Time Trade-Off Tasks: Results from a Pilot Study

INTRODUCTION

Carer quality of life (QoL) can be included in economic evaluations and captured using EQ-5D. Traditional valuation tasks require participants to imagine living in a health state for a number of years, without being told what to consider. This pilot study sought to investigate whether participants implicitly consider the impact of the health state on others, and the extent to which this may impact health state valuations.

METHODS

Composite time trade-off (TTO) interviews were conducted with a convenience sample. Each interview included a 'traditional' TTO exercise to value three health states, and a 'combined' TTO exercise, where participants valued the same health states again, having been informed that they would require a carer living in a particular health state. Qualitative feedback was collected after each exercise. Paired t-test comparisons of the utilities elicited in each exercise were made.

RESULTS

Thirty-three participants enrolled in the pilot. Mean differences between exercises were not statistically significant and differed in direction, although considerable heterogeneity was observed in individual response trajectories. Overall, 36% (n = 12) of participants expressed an unprompted concern about being a burden on others in the traditional exercise, and 67% (n = 22) of participants would have responded differently had the carer been in full health in the combined exercise.

CONCLUSION

Providing contextual information about carers may impact valuations. Further research is required to better understand the reasons behind the variation in individual response trajectories observed in this pilot study. The insights from this study may be useful for informing the design of related future studies.