Do Discrete Choice Experiments Approaches Perform Better Than Time Trade-Off in Eliciting Health State Utilities? Evidence From SF-6Dv2 in China

Choice Consistency in Discrete Choice Experiments: Does Numeracy Skill Matter?

OBJECTIVES

This study investigated the relationship between numeracy skills (NS) and choice consistency in discrete choice experiments (DCEs).

METHODS

A DCE was conducted to explore patients' preferences for kidney transplantation in Italy. Patients completed the DCE and answered 3-item numeracy questions. A heteroskedastic multinomial logit model was used to investigate the effect of numeracy on choice consistency.

RESULTS

Higher NS were associated with greater choice consistency, increasing the scale to 1.63 (P < .001), 1.39 (P < .001), and 1.18 (P < .001) for patients answering 3 of 3, 2 of 3, and 1 of 3 questions correctly, respectively, compared with those with no correct answers. This corresponded to 63%, 39%, and 18% more consistent choices, respectively. Accounting for choice consistency resulted in varying willingness-to-wait (WTW) estimates for kidney transplant attributes. Patients with the lowest numeracy (0/3) were willing to wait approximately 42 months [95% CI: 29.37, 54.68] for standard infectious risk, compared with 33 months [95% CI: 28.48, 38.09] for 1 of 3, 28 months [95% CI: 25.13, 30.32] for 2 of 3, and 24 months [95% CI: 20.51, 27.25] for 3 of 3 correct answers. However, WTW differences for an additional year of graft survival and neoplastic risk were not statistically significant across numeracy levels. Supplementary analyses of 2 additional DCEs on COVID-19 vaccinations and rheumatoid arthritis, conducted online, supported these findings: higher NS were associated with more consistent choices across different disease contexts and survey formats.

CONCLUSIONS

The findings suggested that combining patients with varying NS could bias WTW estimates, highlighting the need to consider numeracy in DCE data analysis and interpretation.

A Spanish value set for the SF-6D based on the SF-12 v1

AIM

This paper reports the first estimation of an SF-6D value set based on the SF-12 for Spain.

METHODS

A representative sample (n = 1020) of the Spanish general population valued a selection of 56 hypothetical SF-6D health states by means of a probability lottery equivalent (PLE) method. The value set was derived using both random effects and mean models estimated by ordinary least squares (OLS). The best model was chosen on the basis of its predictive ability assessed in terms of mean absolute error (MAE).

RESULTS

The model yielding the lowest MAE (0.075) was that based on main effects using OLS. Pain was the most significant dimension in predicting health state severity. Comparison with the previous SF-6D (SF-36) model estimated for Spain revealed no significant differences, with a similar MAE (0.081). Nevertheless, the new SF-6D (SF-12) model predicted higher utilities than those generated by the SF-6D (SF-36) scoring algorithm (minimum value - 0.071 vs - 0.357).

CONCLUSION

A value set for the SF-6D (SF-12) based on Spanish general population preferences elicited by means of a PLE technique is successfully estimated. The new estimated SF-6D (SF-12) preference-based measure provides a valuable tool for researchers and policymakers to assess the cost-effectiveness of new health technologies in Spain.

Comparing the measurement properties of the EQ-5D-5 L, SF-6Dv2, QLU-C10D and FACT-8D among survivors of classical Hodgkin's lymphoma

OBJECTIVE

This study aimed to evaluate the measurement properties of EQ-5D-5 L, SF-6Dv2, QLU-C10D, and FACT-8D in survivors of Classical Hodgkin's Lymphoma (CHL).

METHODS

A cross-sectional, web-based survey was conducted from May to August 2022 to collect data. Chinese value sets were used to estimate the utility scores for EQ-5D-5 L, SF-6Dv2, and QLU-C10D, while the Australian value set was used for FACT-8D. The measurement properties assessed included ceiling and floor effects, convergent validity (assessing associations between similar dimensions/utility scores using Spearman's rank correlation and intraclass correlation coefficient), and known-group validity (measures could differentiate health-related quality of life (HRQoL) between risk groups).

RESULTS

A total of 534 CHL survivors participated in the survey and completed the questionnaire. All dimensions of EQ-5D-5 L, SF-6D (except for vitality), QLU-C10D, and FACT-8D showed ceiling effects, ranging from 18 to 91.6%. The EQ-5D-5 L demonstrated the higher ceiling effects compared to other measures, with 33% of patients reporting full health on this scale. All 30 pairs of associations between similar dimensions from the four measures were statistically significant, with correlation coefficients ranging from 0.29 to 0.77. Regarding utility scores, the EQ-5D-5 L utility score showed a stronger correlation with SF-6Dv2 than with the other two measures. Statistically significant correlations of utility scores between the four measures were observed. EQ-5D-5 L can significantly differentiate HRQoL among all known-groups, while SF-6Dv2, QLU-C10D, and FACT-8D showed a less strong discriminant ability.

CONCLUSIONS

EQ-5D-5 L outperformed SF-6Dv2 in terms of agreement with cancer-specific PRMs and discriminant ability. However, SF-6Dv2 showed stronger associations with similar dimensions of QLU-C10D and FACT-8D, indicating high convergent validity. The generic PBMs are sensitive enough to measure HRQoL in survivors of CHL.

Generating Utilities for the Château-Santé Base: A Novel, Generic, and Patient-Centered Health-Outcome Measure

OBJECTIVES

We have developed a new patient-centered, preference-based generic health-outcome measure, Château-Santé Base (CS-Base), which is based on a novel multiattribute preference response (MAPR) measurement framework. This study aimed to generate a first utility set for the CS-Base, making it suitable for use in health-economic evaluations.

METHODS

CS-Base comprises 12 health attributes: mobility, vision, hearing, cognition, mood, anxiety, pain, fatigue, social functioning, daily activities, self-esteem, and independence, each with 4 levels. Our methodology to generate utilities for the CS-Base was 2-fold. First, we derived coefficients from patient MAPR data to calculate CS-Base values. Subsequently, these were normalized to a 0.0 to 1.0 utility scale, in which 0.0 signifies dead. The dead position was estimated using general population data from a discrete choice experiment (discrete choice experiment + dead), using a division-value strategy, which localize the position of states better or worse than dead.

RESULTS

We analyzed MAPR data from 3222 patients and discrete choice experiment + dead data from 1995 respondents. All MAPR coefficients were negative, logically ordered, and significantly different from the reference level. The dead position was denoted by a division value of -148.385. Utility values spanned from -0.071 to 1.0, and only 53 of 16 777 216 states were deemed worse than dead.

CONCLUSIONS

This study introduced the first CS-Base utility set, underlining a 2-step utility derivation method. This method, blending societal and patient views, surpasses traditional preference-based approaches, yielding firmer results. However, improvement of the normalization procedure is expected. Estimating CS-Base utilities is an ongoing process that gains precision over time.

Comparison of four approaches in eliciting health state utilities with SF-6Dv2

OBJECTIVE

To empirically compare four preference elicitation approaches, the discrete choice experiment with time (DCETTO), the Best-Worst Scaling with time (BWSTTO), DCETTO with BWSTTO (DCEBWS), and the Standard Gamble (SG) method, in valuing health states using the SF-6Dv2.

METHODS

A representative sample of the general population in Quebec, Canada, completed 6 SG tasks or 13 DCEBWS (i.e., 10 DCETTO followed by 3 BWSTTO). Choice tasks were designed with the SF-6Dv2. Several models were used to estimate SG data, and the conditional logit model was used for the DCE or BWS data. The performance of SG models was assessed using prediction accuracy (mean absolute error [MAE]), goodness of fit using Bayesian information criterion (BIC), t-test, Jarque-Bera (JB) test,  Ljung-Box (LB) test, the logical consistency of the parameters, and significance levels. Comparison between approaches was conducted using acceptability (self-reported difficulty and quality levels in answering, and completion time), consistency (monotonicity of model coefficients), accuracy (standard errors), dimensions coefficient magnitude, correlation between the value sets estimated, and the range of estimated values. The variance scale factor was computed to assess individuals' consistency in their choices for DCE and BWS approaches.

RESULTS

Out of 828 people who completed SG and 1208 for DCEBWS tasks, a total of 724 participants for SG and 1153 for DCE tasks were included for analysis. Although no significant difference was observed in self-reported difficulties and qualities in answers among approaches, the SG had the longest completion time and excluded participants in SG were more prone to report difficulties in answering. The range of standard errors of the SG was the narrowest (0.012 to 0.015), followed by BWSTTO (0.023 to 0.035), DCEBWS (0.028 to 0.050), and DCETTO (0.028 to 0.052). The highest number of insignificant and illogical parameters was for BWSTTO. Pain dimension was the most important across dimensions in all approaches. The correlation between SG and DCEBWS utility values was the strongest (0.928), followed by the SG and BWSTTO values (0.889), and the SG and DCETTO (0.849). The range of utility values generated by SG tended to be shorter (-0.143 to 1) than those generated by the other three methods, whereas BWSTTO (-0.505 to 1) range values were shorter than DCETTO (-1.063 to 1) and DCEBWS (-0.637 to 1). The variance scale factor suggests that respondents had almost similar level of certainty or confidence in both DCE and BWS responses.

CONCLUSION

The SG had the narrowest value set, the lowest completion rates, the longest completion time, the best prediction accuracy, and produced an unexpected sign for one level. The BWSTTO had a narrower value set, lower completion time, higher parameter inconsistency, and higher insignificant levels compared to DCETTO and DCEBWS. The results of DCEBWS were more similar to SG in number of insignificant and illogical parameters, and correlation.

A novel approach for health state valuation: Multiple bounded dichotomous choice compared to the traditional standard gamble

OBJECTIVE

to assess the feasibility of a new stated preference approach, the multiple bounded dichotomous choice (MBDC), designed to generate value sets for preference-based measurement of health-related quality of life.

METHODS

MBDC and standard gamble (SG) tasks were completed to derive SF-6Dv2 value sets from a sample of the general population in Quebec, Canada. Participants were randomized between the two approaches: 6 health states were evaluated in SG and 11 health states in MBDC. Several models were used to estimate data in each approach, and the preferred models were chosen by using mean absolute error (MAE), logical consistency of parameters, and significance levels. Results of MBDC were compared with SG in terms of acceptability (self-reported difficulty and quality levels in answering, and completion time), consistency (monotonicity of model coefficients), accuracy (standard errors), dimensions coefficient magnitude, correlation between the value sets estimated, and the range of estimated values. The intra-class correlation coefficient (ICC) was computed to assess value sets' consistency.

RESULTS

Out of 655 individuals who completed MBDC tasks and 828 who completed SG tasks, a total of 585 participants for MBDC and 714 for SG tasks were included for analysis. The preferred models for both approaches were GLS Tobit. No significant difference was observed in self-reported difficulties and qualities in answers among approaches, but MBDC had less excluded participants and was less prone to report difficulties in answering. Additionally, completion time in the MBDC group was significantly lower (99.80 vs 68.12 s). Most standard errors in the MBDC were lower than those in SG, and the number of non-significant parameters was also lower. The range of utility values generated by MBDC tended to be wider (-0.372 to 1) than those generated by the SG (-0.137 to 1) and the number of worse-than-dead states in MBDC (0.91%) was higher than for SG (0.08%). The Pain dimension was identified as the most significant, while the Vitality dimension showed the lowest significant decrement. Both approaches exhibited a tendency to overestimate severe health state values and underestimate better health state values. The correlation and ICC between the two value sets were 0.937 and 0.983, respectively.

CONCLUSION

Based on empirical evidence, it can be inferred that the MBDC method is not only feasible but also holds the potential to generate meaningful and well-informed preference data from respondents. This approach can be used to derive a value set for preference-based instrument.

Valuing quality of life for economic evaluations in cancer: navigating multiple methods

INTRODUCTION

Utility values offer a quantitative means to evaluate the impact of novel cancer treatments on patients' quality of life (QoL). However, the multiple methods available for valuing QoL present challenges in selecting the most appropriate method across different contexts.

AREAS COVERED

This review provides cancer clinicians and researchers with an overview of methods to value QoL for economic evaluations, including standalone and derived preference-based measures (PBMs) and direct preference elicitation methods. Recent developments are described, including the comparative performance of cancer-specific PBMs versus generic PBMs, measurement of outcomes beyond health-related QoL, and increased use of discrete choice experiments to elicit preferences. Recommendations and considerations are provided to guide the choice of method for cancer research.

EXPERT OPINION

We foresee continued adoption of the QLU-C10D and FACT-8D in cancer clinical trials given the extensive use of the EORTC QLQ-C30 and FACT-G in cancer research. While these cancer-specific PBMs offer the convenience of eliciting utility values without needing a standalone PBM, researchers should consider potential limitations if they intend to substitute them for generic PBMs. As the field advances, there is a greater need for consensus on the approach to selection and integration of various methods in cancer clinical trials.

Creating an SF-6Dv2 social value set for New Zealand

The SF-6D health descriptive system and its second version published in 2020, the SF-6Dv2, is used worldwide for valuing health-related quality of life (HRQoL) for economic evaluation and measuring patient-reported health outcomes. In this study, a valuation tool was developed and applied to create a social value set, comprising 18,750 health state values, for the SF-6Dv2 for New Zealand (NZ). This tool was adapted and extended from the one used to create a social value set for the EQ-5D-5L, a simpler health descriptive system with fewer dimensions and health states. The tool implements the PAPRIKA method, a type of adaptive discrete choice experiment, and a binary search algorithm to identify health states worse than dead and has extensive data quality controls to ensure the validity and reliability of the social value set derived from participants' personal value sets. The tool, accompanied by a short introductory video designed specifically for the SF-6Dv2, was distributed via an online survey to a large representative sample of adult New Zealanders in June-July 2022. The tool's data quality controls enabled participants who failed to understand or sincerely engage with the valuation tasks to be identified and excluded, resulting in the participants being pared down to a sub-sample of 2985 'high-quality' participants whose personal value sets were averaged for the social value set. These results, including participants' positive feedback, demonstrate the feasibility and acceptability of using the tool to value larger health descriptive systems such as the SF-6Dv2. Having successfully created an SF-6Dv2 social value set for NZ, the valuation tool can be readily applied to other countries, used to generate personal value sets for personalised medicine and adapted to create value sets for other health descriptive systems.

Understanding Canadian stakeholders' views on measuring and valuing health for children and adolescents: a qualitative study

OBJECTIVE

Valuing child health is critical to assessing the value of healthcare interventions for children. However, there remain important methodological and normative issues. This qualitative study aimed to understand the views of Canadian stakeholders on these issues.

METHODS

Stakeholders from health technology assessment (HTA) agencies, pharmaceutical industry representatives, healthcare providers, and academic researchers/scholars were invited to attend an online interview. Semi-structured interviews were designed to focus on: (1) comparing the 3-level and 5-level versions of the EQ-5D-Y; (2) source of preferences for valuation (adults vs. children); (3) perspective of valuation tasks; and (4) methods for valuation (discrete choice experiment [DCE] and its variants versus time trade-off [TTO]). Participants were probed to consider HTA guidelines, cognitive capacity, and potential ethical concerns. All interviews were recorded and transcribed verbatim. Framework analysis with the incidence density method was used to analyze the data.

RESULTS

Fifteen interviews were conducted between May and September 2022. 66.7% (N = 10) of participants had experience with economic evaluations, and 86.7% (N = 13) were parents. Eleven participants preferred the EQ-5D-Y-5L. 12 participants suggested that adolescents should be directly involved in child health valuation from their own perspective. The participants were split on the ethical concerns. Eight participants did not think that there was ethical concern. 11 participants preferred DCE to TTO. Among the DCE variants, 6 participants preferred the DCE with duration to the DCE with death.

CONCLUSIONS

Most Canadian stakeholders supported eliciting the preferences of adolescents directly from their own perspective for child health valuation. DCE was preferred if adolescents are directly involved.

The Impact of Underlying Conditions on Quality-of-Life Measurement Among Patients with Chronic Wounds, as Measured by Utility Values: A Review with an Additional Study

Significance: Quality of life (QoL) is important to patients with chronic wounds and is rarely formally evaluated. Understanding what comorbidities most affect the individual versus their wounds could be a key metric. Recent Advances: The last 20 years have seen substantial advances in QoL instruments and conversion of patient data to a single value known as the health utilities index (HUI). We review these advances, along with wound-related QoL, and analyze real-world comorbidities challenging wound care. Critical Issues: To understand the impact of underlying comorbidities in a real-world patient population, we examined a convenience sample of 382 patients seen at a hospital-based outpatient wound center. This quality reporting study falls outside the regulations that govern human subject research. Comorbid conditions were used to calculate HUIs using a variety of literature-reported approaches, while Wound-Quality-of-Life (W-QoL) questionnaire data were collected from patients during their first visit. The mean number of conditions per patient was 8; 229 patients (59.9%) had utility values for comorbidities/conditions, which were worse/lower than their wounds' values. Sixty-three (16.5%) patients had depression and/or anxiety, 64 (16.8%) had morbid obesity, and 204 (53.4%) had gait and mobility disorders, all of which could have affected W-QoL scoring. The mean minimum utility value (0.5) was within 0.05 units of an average of 13 studies reporting health utilities from wound care populations using the EuroQol 5 Dimension instrument. Future Directions: The comorbidity associated with the lowest utility value is what might most influence the QoL of patients with chronic wounds. This finding needs further investigation.

Whose Time Trade-Off Should Be Used? Anchoring Discrete Choice Experiment Latent Utilities in Health State Valuation

OBJECTIVES

To compare anchored discrete choice experiment (DCE) utility values using own versus others' time trade-off (TTO) responses in the valuation of SF-6Dv2.

METHODS

A representative sample of the general population was recruited in China. Through face-to-face interviews, both DCE and TTO data were collected from a randomly selected half of the respondents (own TTO sample), whereas only TTO data were collected from the other half (others' TTO sample). Conditional logit model was used to estimate DCE latent utilities. Three anchoring methods, including using the observed and the modeled TTO values for the worst state, and mapping DCE values onto TTO, were used to scale the latent utilities to health utilities. Prediction accuracy was assessed using intraclass correlation coefficient, mean absolute difference, and root mean squared difference compared with the mean observed TTO values between the anchoring results using the own versus others' TTO data.

RESULTS

Demographic characteristics were comparable between the own TTO sample (n = 252) and the others' TTO sample (n = 251). The mean (SD) observed TTO value for the worst state was -0.259 (0.591) for the own TTO sample and -0.236 (0.616) for the others' TTO sample. Anchoring DCE using own TTOs consistently showed a better prediction accuracy than using others' TTOs across the 3 anchoring methods in terms of the intraclass correlation coefficient (0.835-0.873 vs 0.771-0.804), mean absolute difference (0.127-0.181 vs 0.146-0.203), and root mean squared difference (0.164-0.237 vs 0.192-0.270).

CONCLUSION

When anchoring DCE-derived latent utilities onto the health utility scale, respondents' own TTO data would be preferred to TTO data obtained from a different sample.

Valuing Chinese medicine quality of life-11 dimensions (CQ-11D) health states using a discrete choice experiment with survival duration (DCETTO)

OBJECTIVE

To explore generating a health utility value set for the Chinese medicine Quality of life-11 Dimensions (CQ-11D), a utility instrument designed to assess patients' health status while receiving TCM treatment, among the Chinese population.

METHODS

The study was designed to recruit at least 2400 respondents across mainland China to complete one-to-one, face-to-face interviews. Respondents completed ten discrete choice experiment with survival duration (DCETTO) tasks during interviews. The conditional logit models were used to generate the health utility value set for the CQ-11D using the DCETTO data.

RESULTS

A total of 2,586 respondents were invited to participate in the survey and 2498 valid interviews were completed (a completion rate of 96.60%). The modified conditional logit model with combing logically inconsistent levels was ultimately selected to construct the health utility value set for the CQ-11D instrument. The range of the measurable health utility value was -0.868 ~ 1.

CONCLUSION

The study provides the first utility value set for the CQ-11D among the Chinese population. The CQ-11D and corresponding utility value set can be used to measure the health utility values of patients undergoing traditional Chinese medicine interventions, and further facilitate relevant cost-utility analyses. The application of the CQ-11D can support TCM resource allocation in China.

I-PreFer Study: A Discrete Choice Experiment to Explore Patient, Caregiver and Pulmonologist Preferences of Idiopathic Pulmonary Fibrosis Pharmacological Treatment Options

Purpose

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and ultimately fatal lung disease that, while rare, has seen incidence rise over time. There is no cure for IPF other than a lung transplant, though two antifibrotic (AF) drugs do exist to slow disease progression. While these drugs are efficacious, they are both associated with differing profiles of adverse events. This study aimed to elicit patient, caregiver and pulmonologist preferences on the treatment profiles of AFs via a discrete choice experiment (DCE).

Patients and Methods

The DCE and associated survey were distributed across 7 European countries, and bespoke DCEs were developed for patients/caregivers and pulmonologists. After collaboration with European Pulmonary Fibrosis & Related Disorders Federation (EU-PFF) and expert pulmonologists, respectively, a patient/caregiver DCE with 5 attributes and a pulmonologist DCE with 6 attributes were finalized. The DCEs had a blocked approach to reduce participant burden and were distributed on an online survey platform. Preferences were estimated through conditional multinomial logit regression analysis.

Results

Ninety-five patients, 22 caregivers and 115 pulmonologists fully completed their respective DCEs. Overall, patients and caregivers preferred management of treatment-related adverse events over both survival benefits and disease progression. Nearly all preference levels were found to be significantly different from their reference level. In contrast, pulmonologists showed a greater preference for control of lung function and exacerbations over adverse events. Although there were relative differences between the univariate subgroups in terms of the preference weights, most of these were not statistically significant.

Conclusion

The outcomes from this study suggest that while patients and caregivers had similar preferences for characteristics of IPF treatments, pulmonologists did not share those same preferences. Patients and caregivers preferred safety, while pulmonologists preferred efficacy. These differences should be considered by clinicians to better involve the patient in treatment decision-making for IPF.

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.

Modifying the Composite Time Trade-Off Method to Improve Its Discriminatory Power

OBJECTIVES

In cost-effectiveness analysis of health technologies, health state utilities are needed. They are often elicited with a composite time trade-off (cTTO) method, particularly for the widely used EQ-5D-5L. Unfortunately, cTTO discriminatory power is hindered by (1) respondents' nontrading (NT) of time for quality, (2) censoring of utilities at -1, and (3) poor correlation of negative utilities with state severity. We investigated whether modifying cTTO can mitigate these effects.

METHODS

We interviewed online 478 students (February to April, 2021) who each valued the same 10 EQ-5D-5L health states in 1 of 3 arms. Arm A used a standard cTTO, expanded with 2 questions to explore reasons for NT and censoring. Arms B and C used a time trade-off with modified alternatives offered to overcome loss aversion, to unify the tasks for positive and negative utilities, and to enable eliciting utilities < -1.

RESULTS

In arms B and C, we observed less NT than in A (respectively, 4% and 4% vs 10%), more strictly negative utilities (38% and 40% vs 25%), and more utilities ≤ -1 (18% and 30% vs 10%). The average utility of state 55555 dropped to -2.15 and -2.52 from -0.53. Enabling finer trades in arm A reduced NT by 70%. Arms B and C yielded an intuitive association between negative utilities and state severity. These arms were considered more difficult and resulted in more inconsistencies.

CONCLUSIONS

The discriminatory power of cTTO can be improved, but it may require increasing the difficulty of the task. The standard cTTO may overestimate the utilities, especially of severe states.

Comparison of EQ-5D-5L and EORTC QLU-C10D utilities in gastric cancer patients

BACKGROUND

To compare measurement properties of the utility scores derived from various country-specific value sets of EQ-5D-5L (5L) and EORTC QLU-C10D (10D) in gastric cancer patient.

METHODS

The study used cross-sectional data of 243 Chinese gastric cancer patients who completed both 5L and EORTC QLQ-C30. Utility score of QLU-C10D is generated from all the available QLU-C10D value sets currently; the score of 5L is derived from the corresponding 5L value sets for the countries with both the 5L and QLU-C10D value sets and the Chinese 5L value set. Convergent validity was evaluated by testing their correlations with the VAS score. Known-group validity was assessed by comparing the utility scores the patients with different severities. Their relative efficiency (RE) was also compared.

RESULTS

Correlation coefficient of 5L and QLU-C10D utility scores with VAS ranged from 0.54 to 0.59, and 0.55 to 0.63, respectively. Both the utility scores were in general able to discriminate the patients with different severities; and 5L utility score had higher RE in the majority of known-groups.

CONCLUSION

EQ-5D-5L and QLU-C10D utility scores were different and, thus, non-swappable. They possess similar convergent validity and known-group validity; while EQ-5D-5L scores may have better discriminative power.

Population Norms for SF-6Dv2 and EQ-5D-5L in China

OBJECTIVES

To derive the population norms for EQ-5D-5L and SF-6Dv2 among the Chinese general population.

METHODS

Data collected alongside the Chinese SF-6Dv2 valuation study conducted between June and September 2019 were used. SF-6Dv2 and EQ-5D-5L, as well as social-demographic characteristics and self-reported chronic conditions, were collected through face-to-face interviews among a representative sample of the general population stratified by age, gender, education, and area of residence (urban/rural) in China. SF-6Dv2 and EQ-5D-5L responses were converted to utility values using the corresponding Chinese value sets. Utility values for both measures and EQ VAS scores were summarized by age and gender, and then described by different social-demographic characteristics and chronic conditions.

RESULTS

A total of 3397 respondents (51.2% male, age range 18-90 years) were included. 420 (12.4%) and 1726 (50.8%) respondents reported no problems on all SF-6Dv2 and EQ-5D-5L dimensions, respectively. The mean [standard deviation (SD)] utility values were 0.827 (0.143) for SF-6Dv2 and 0.946 (0.096) for EQ-5D-5L. The mean (SD) EQ VAS score was 87.1 (11.5). Respondents who resided in rural areas, were married, and were employed had higher utility values. Respondents with memory-related diseases or stroke had lower utility values than those with other chronic conditions. Utility values decreased with the increase in the number of chronic conditions.

CONCLUSION

This study reports the first Chinese population norms for the EQ-5D-5L and SF-6Dv2 derived using a representative sample of the Chinese general population. The norms can be used as references for economic evaluations and healthcare decision-making in China.

Health-related quality of life among adults with haemophilia in China: A comparison with age-matched general population

INTRODUCTION

Evaluating health-related quality of life (HRQoL) is vital for informing the improvement of the overall health of people with haemophilia (PwH). While there is lacking such data in China and comparisons with the general population.

AIM

To evaluate the HRQoL and its associated factors among adults with haemophilia, and compare it with a sample of the general population in China.

METHODS

PwH were recruited in this study using telephone-based interviews. Demographic and clinical characteristics were first collected. HRQoL was then evaluated using the self-reported Short Form 6-dimensions version 2 (SF-6Dv2) instrument. An age and gender-matched sample of the general population in China was also included as the comparator group. Linear regression was used to assess the association between the SF-6Dv2 utility value and the demographic and clinical variables of the patients.

RESULTS

This study included 206 PwH (mean [SD] age: 41.36 [14.48] years) and 206 respondents from the general population. PwH reported worse levels in physical functioning, role limitation, social functioning, and mental health dimensions on SF-6Dv2 than the general respondents. The mean (SD) utility of patients was .650 (.251), which was significantly lower than the general respondents (.786 [.183], P < .001). Being a student, having a higher monthly income, absence of comorbidities, having no target joints and requiring no treatment are independent predictors of a higher HRQoL for PwH.

CONCLUSION

This study provides the first practical evidence of a significantly lower level of HRQoL in PwH than in the general population in China.

Discrete choice experiment with duration versus time trade-off: a comparison of test-retest reliability of health utility elicitation approaches in SF-6Dv2 valuation

OBJECTIVES

To evaluate and compare the test-retest reliability of discrete choice experiments with duration (DCE_TTO) and time trade-off (TTO) in the Chinese SF-6Dv2 valuation study.

METHODS

During face-to-face interviews, a representative sample of the Chinese general population completed 8 TTO tasks and 10 DCE_TTO tasks. Retest interviews were conducted after two weeks. For both DCE_TTO and TTO, the consistency of raw responses between the two tests was firstly evaluated at the individual level. Regressions were conducted to investigate the association between the test-retest reliability and the respondents' characteristics and the severity of health states. Consistency was then analyzed at the aggregate level by comparing the rank order of the coefficients of dimensions.

RESULTS

In total, 162 respondents (51.9% male; range 18-80 years) completed the two tests. The intraclass correlations coefficient 0.958 for TTO, with identical values accounting for 59.3% of observations. 76.4% of choices were identical for DCE_TTO, with a Kappa statistic of 0.528. Respondents' characteristics had no significant impact while the severity of health states valued in TTO and DCE_TTO tasks had a significant impact on the test-retest reliability. Both approaches produced relatively stable rank order of dimensions in constrained model estimations between test and retest data.

CONCLUSIONS

Individual responses of both approaches are relatively stable over time. The rank orders of dimensions in model estimations between test and retest for TTO and DCE_TTO are also consistent. The differences of utility estimation between the two tests for DCE_TTO need to be further investigated based on a larger sample size.

The Danish EQ-5D-5L Value Set: A Hybrid Model Using cTTO and DCE Data

OBJECTIVES

Quality-adjusted life-years (QALYs) are expected to be used for priority setting of hospital-dispensed medicines in Denmark from 2021. The aim of this study was to develop the first Danish value set for the EQ-5D-5L based on interviews with a representative sample of the Danish adult population.

METHODS

A nationally representative sample based on age (> 18 years), gender, education, and geographical region was recruited using data provided by Statistics Denmark. Computer-assisted personal interviews were carried out using the EQ-VT 2.1. Respondents each valued ten health states using composite time trade-off (cTTO) and seven health states using discrete-choice experiment (DCE). Different predictive models were explored using cTTO and DCE data alone or in combination as hybrid models. Model performance was assessed using logical consistency.

RESULTS

A total of 1014 interviews were included in the analyses. The sample was representative of the Danish adult population, though the sample contained slightly more respondents with higher education than in the general population. Only the heteroscedastic censored hybrid model combining cTTO and DCE data yielded consistent results, and hence was chosen for modelling the final Danish value set. The predicted values ranged from - 0.757 to 1, and anxiety/depression was the dimension assigned most value by respondents.

CONCLUSIONS

This study established the Danish EQ-5D-5L value set, which represents the preferences of the Danish general population, and is expected to provide key input for healthcare decision-making in a Danish context.

Valuation of SF-6Dv2 Health States in China Using Time Trade-off and Discrete-Choice Experiment with a Duration Dimension

OBJECTIVES

Our objective was to generate a value set for the SF-6Dv2 using time trade-off (TTO) and a discrete-choice experiment with a duration dimension (DCE_TTO) in China.

METHODS

A large representative sample of the Chinese general population was recruited from eight provinces/municipalities in China, stratified by age, sex, education level, and proportion of urban/rural residence. Respondents completed eight TTO tasks and ten DCE_TTO tasks during face-to-face interviews. Ordinary least squares (OLS), random-effects, fixed-effects, and Tobit models were used for TTO data, and conditional logit and mixed logit models were used for DCE_TTO. The monotonicity of model coefficients and the consistency of the predicted values according to intraclass correlation coefficient (ICC), mean absolute difference (MAD), and mean squared difference (MSD) were compared between the two approaches.

RESULTS

In total, 3320 respondents (50.3% male; range 18-90 years) were recruited. The random-effects model and the conditional logit model were preferred for the TTO and DCE_TTO, respectively. The TTO values ranged from - 0.277 to 1, with 927 (4.94%) states considered as worse than dead (WTD). The corresponding range for DCE_TTO was - 0.535 to 1, with a higher WTD of 8.50%. DCE_TTO presented minor non-monotonicity with the coefficients in two dimensions. Values from the two approaches were highly consistent (ICC 0.9804, MAD 0.0588, MSD 0.0055), albeit those with DCE_TTO were slightly lower than those with TTO. The value set generated by TTO was preferred given the better monotonicity and the statistical significance of coefficients.

CONCLUSIONS

The Chinese value set for the SF-6Dv2 was established based on the TTO approach, but the DCE_TTO also performed well. Minor issues of non-monotonicity did present for DCE_TTO.