Selecting Bolt-On Dimensions for the EQ-5D: Examining Their Contribution to Health-Related Quality of Life

A Head-to-Head Comparison of EQ Health and Wellbeing and EQ-5D-5L in Patients, Carers, and General Public in China

OBJECTIVES

This study aimed to understand the psychometric properties of EQ Health and Wellbeing (EQ-HWB) and to examine its relationship with EQ-5D-5L in a sample covering patients, carers, and general public.

METHODS

A cross-sectional study was conducted in Guizhou Province, China. The acceptability, convergent validity (using Spearman correlation coefficients), internal structure (using exploratory factor analysis), and known-group validity of EQ-HWB, EQ-HWB-Short (EQ-HWB-S), and EQ-5D-5L were reported and compared.

RESULTS

A total of 323 participants completed the survey, including 106 patients, 101 carers, and 116 individuals from the general public. Approximately 7.4% of participants had at least 1 missing response. In the EQ-HWB and EQ-5D-5L items related to activities, there were more level 1 responses. The correlations between EQ-HWB and EQ-5D-5L items ranged from low to high, confirming the convergent validity of similar aspects between the 2 instruments. Notably, EQ-HWB measures 2 additional factors compared with EQ-5D-5L or EQ-HWB-S, both of which share 3 common factors. When the patient group was included, EQ-5D-5L had the largest effect size, but it failed to differentiate between the groups of general public and carers. Both EQ-HWB and EQ-HWB-S demonstrated better known-group validity results when carers were included.

CONCLUSIONS

EQ-HWB measures a broader quality of life construct that goes beyond health measured by EQ-5D-5L. By encompassing a broader scope, the impact of healthcare interventions may become diluted, given that other factors can influence wellbeing outcomes as significantly as health conditions do.

Measuring Quality of Life in Diabetic Retinal Disease: A Narrative Review of Available Patient-Reported Outcome Measures

Topic

Several patient-reported outcome measures (PROMs) are available to measure health-related quality of life (HRQoL) in patients with late-stage clinical diabetic retinal diseases (DRDs). However, an understanding of the psychometric properties of PROMs is needed to assess how they could relate to severity levels of a revised DRD grading system. This narrative review assessed the available generic-, vision-, and DRD-related PROMs used in DRD research and highlights areas for improvement.

Clinical Relevance

Diabetic retinal disease is a common complication of diabetes and can lead to sight-threatening complications with a devastating effect on HRQoL.

Methods

The Quality of Life working group is one of 6 working groups organized for the DRD Staging System Update Effort, a project of the Juvenile Diabetes Research Foundation Mary Tyler Moore Vision Initiative. PubMed, Cochrane Library, Embase, and Google Scholar databases were searched using core keywords to retrieve ophthalmology-related review articles, randomized clinical trials, and prospective, observational, and cross-sectional studies in the English language. A detailed review of 12 PROMs (4 QoL questionnaires and 8 utilities) that met a minimum level of evidence (LOE) was conducted. The relevance of each PROM to DRD disease stage and Biomarker Qualification guidelines (Biomarkers, EndpointS, and other Tools) categories was also defined.

Results

The National Eye Institute 25-item Visual Function Questionnaire (NEI VFQ-25), Impact of vision impairment-computerized adaptive testing, and Diabetic Retinopathy and Macular Edema Computerized Adaptive Testing System had a LOE of II in detecting change due to late-stage DRD (diabetic macular edema), although several areas for improvement (e.g., psychometrics and generalizability) were identified. Other PROMs, particularly the utilities, had a LOE of III due to cross-sectional evidence in late-stage clinical DRD. Although the NEI VFQ-25 has been the most widely used PROM in late-stage DRD, more work is required to improve its multidimensional structure and other psychometric limitations. No PROM was deemed relevant for subclinical or early/mid-DRD.

Conclusion

This narrative review found that the most commonly used PROM is NEI VFQ-25, but none meets the ideal psychometric, responsiveness, and clinical setting digital administration requirements that could be included in an updated DRD staging system for diagnosis and monitoring of DRD progression.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Exploring the measurement of health related quality of life and broader instruments: A dimensionality analysis

BACKGROUND

Comprehensively measuring the outcomes of interventions and policy programmes impacting both health and broader areas of quality of life (QoL) is important for decision-making within and across sectors. Increasingly, broad QoL measures are being developed to capture outcomes beyond health-related quality of life (HRQoL). Jointly exploring the dimensionality of diverse instruments can improve our understanding about their evaluative space and how they conceptually build on each other. This study explored the measurement relationship between five broader QoL measures and the most widely used HRQoL measure, the EQ-5D.

METHODS

Participants from the Dutch general population (n = 1002) completed six instruments (n = 126 items) in December of 2020. The measurement relationship was explored using qualitative and quantitative dimensionality assessment methods. This included a content analysis and exploratory factor analyses which were used to develop a confirmatory factor model of the broader QoL dimensions. Correlations between the identified dimensions and self-reported overall health and wellbeing were also explored.

RESULTS

The final CFA model exhibited acceptable/good fit and described 12 QoL dimensions: 'psychological symptoms', 'social relations', 'physical functioning', 'emotional resilience', 'pain', 'cognition', 'financial needs', 'discrimination', 'outlook on life/growth', 'access to public services', 'living environment', and 'control over life'. All dimensions were positively correlated to self-reported health and wellbeing, but the magnitudes in associations varied considerably (e.g., 'pain' had the strongest correlation with overall health but a weak correlation with wellbeing).

CONCLUSIONS

This study contributes to a broader understanding of QoL by exploring the dimensionality and relationships among various QoL measures. A number of the dimensions identified are HRQoL-focused, with others covering broader constructs. Our findings offer insights for the development of comprehensive instruments, or use of instrument suites that capture multidimensional aspects of QoL. Further research should explore the relevance and feasibility/appropriateness of measuring the identified dimensions in different settings and populations.

The Burden Patients with Myasthenia Gravis Experience in Terms of Breathing, Fatigue, Sleep, Mental Health, Discomfort and Usual Activities in Comparison to the General Population

INTRODUCTION

Myasthenia gravis (MG) is a rare neuromuscular disorder marked by a variable combination of weakness of eye, bulbar, respiratory, axial, and limb muscles. This study compared the experience of people with MG regarding breathing, fatigue, sleep, pain/discomfort, mental health, and usual activities with the general population.

METHODS

The MyRealWorld-MG digital, multinational study enrolled patients with MG and collected demographics, PROMIS-Dyspnea, PROMIS-Sleep Disturbance, FACIT-Fatigue, EQ-5D-5L, Health Utilities Index (HUI-3), Hospital Anxiety and Depression Scale (HADS), MG-Activities of Daily Living (MG-ADL), and MG-Quality-of-Life (MG-QoL-15r). Comparisons with the general population were based on PROMIS population norms, published literature, or on data from a digital, multinational, observational study which enrolled a representative sample of the general population (POPUP).

RESULTS

In MyRealWorld-MG (N = 2074), patients experienced higher intensity, frequency, and duration of PROMIS shortness of breath than a US population (p < 0.0001). Patients with MG had higher PROMIS-Sleep Disturbance scores than POPUP (53.7 vs 50.0, p < 0.0001), and 54.9% of patients had clinically severe FACIT-Fatigue scores vs 6.8% in POPUP (p < 0.0001). Among patients with MG, 69.6% and 18.5% had moderate-to-severe HADS-Anxiety and HADS-Depression compared to 20.3% and 6.9% in POPUP (p < 0.001). Statistically significant and strong associations were found between fatigue, sleep, dyspnea, usual activities, and emotions. All outcomes worsened with more severe disease.

CONCLUSION

A considerable burden was observed in this comparison of breathing, sleep, fatigue, mental health, and usual activities between patients with MG and the general population, using data from two international studies and published population norms. Even mildly affected patients had significantly worse outcomes than the general population.

A hearing bolt-on item increased the measurement properties of the EQ-5D-5L in a community-based hearing loss screening program

OBJECTIVE

To investigate the measurement properties of a hearing item ('bolt-on') added to the EQ-5D-5L descriptive system.

METHODS

Cross-sectional data on the EQ-5D-5L descriptive system with the addition of a hearing bolt-on item, namely, 'I have no/slight/moderate/severe/extreme problems hearing', was collected through face-to-face interviews with 418 participants of a community-based hearing loss screening program in Singapore. The distribution of responses to the EQ-5D and the hearing items were compared in terms of the proportion of 'no problems' and the Shannon index (H'). The measurement properties of the hearing item were assessed by testing its correlation with the hearing thresholds in dBHL; and with the standard EQ-5D items. The properties were also evaluated by comparing the proportion of 'full health' in participants with different hearing severities between standard and hearing bolt-on EQ-5D-5L; and the ability in identifying the participants between the standard EQ-5D-5L index score and the level sum score (LSS) of the hearing bolt-on system.

RESULTS

Compared to the standard EQ-5D items, the hearing item has a lower proportion of 'no problems' (80.1% vs. 80.9-97.9%); more evenly-distributed responses (H' value: 0.92 vs. 0.18-0.87); and much stronger correlation with the hearing thresholds (|r|: 0.322 and 0.325 vs. 0.008-0.139). It generally has a weak correlation with EQ-5D items (|r|: 0.055-0.160); and reduces the proportion of 'full health' for the participants with different hearing functions with the percentage reduction varying from 6.6 to 22.7%. The LSS is more discriminative than the standard EQ-5D-5L index score as well (F-statistic: 12.71 and 13.93 vs.4.06 and 4.70).

CONCLUSIONS

A hearing bolt-on to EQ-5D-5L can validly measure hearing severities and is likely to increase the sensitivity of the resultant preference-based EQ-5D index to hearing loss.

A head-to-head comparison of the EQ-5D-5L and 15D descriptive systems and index values in a general population sample

BACKGROUND

The EQ-5D-5L and 15D are generic preference-accompanied health status measures with similar dimensions. In this study, we aim to compare the measurement properties of the EQ-5D-5L and 15D descriptive systems and index values in a general population sample.

METHODS

In August 2021, an online cross-sectional survey was conducted in a representative adult general population sample (n = 1887). The EQ-5D-5L and 15D descriptive systems and index values were compared in terms of ceiling and floor, informativity (Shannon's Evenness index), agreement, convergent and known-groups validity for 41 chronic physical and mental health conditions. Danish value sets were used to compute index values for both instruments. As a sensitivity analysis, index values were also estimated using the Hungarian EQ-5D-5L and Norwegian 15D value sets.

RESULTS

Overall, 270 (8.6%) and 1030 (3.4*10^-6%) unique profiles occurred on the EQ-5D-5L and 15D. The EQ-5D-5L dimensions (0.51-0.70) demonstrated better informativity than those of 15D (0.44-0.69). EQ-5D-5L and 15D dimensions capturing similar areas of health showed moderate or strong correlations (0.558-0.690). The vision, hearing, eating, speech, excretion and mental function 15D dimensions demonstrated very weak or weak correlations with all EQ-5D-5L dimensions, which may indicate potential room for EQ-5D-5L bolt-ons. The 15D index values showed lower ceiling than the EQ-5D-5L (21% vs. 36%). The mean index values were 0.86 for the Danish EQ-5D-5L, 0.87 for the Hungarian EQ-5D-5L, 0.91 for the Danish 15D and 0.81 for the Norwegian 15D. Strong correlations were found between the index values (Danish EQ-5D-5L vs. Danish 15D 0.671, Hungarian EQ-5D-5L vs. Norwegian 15D 0.638). Both instruments were able to discriminate between all chronic condition groups with moderate or large effect sizes (Danish EQ-5D-5L 0.688-3.810, Hungarian EQ-5D-5L 1.233-4.360, Danish 15D 0.623-3.018 and Norwegian 15D 1.064-3.816). Compared to the 15D, effect sizes were larger for the EQ-5D-5L in 88-93% of chronic condition groups.

CONCLUSIONS

This is the first study to compare the measurement properties of the EQ-5D-5L and 15D in a general population sample. Despite having 10 fewer dimensions, the EQ-5D-5L performed better than the 15D in many aspects. Our findings help to understand the differences between generic preference-accompanied measures and support resource allocation decisions.

Patient-reported burden of myasthenia gravis: baseline results of the international prospective, observational, longitudinal real-world digital study MyRealWorld-MG

OBJECTIVES

Myasthenia gravis (MG) is a rare, chronic, autoimmune neuromuscular disease which can affect functional and mental aspects of health and health-related quality of life (HRQoL). This study aims to obtain detailed knowledge of the impact of MG on HRQoL in a broad population from the perspective of the patient.

DESIGN

Prospective, observational, digital, longitudinal real-world study.

SETTING

Adult patients with MG from seven countries (USA, Japan, Germany, UK, Italy, Spain and Canada) downloaded a mobile application onto their phones and entered data about themselves and their MG.

OUTCOME MEASURES

Data was collected using the following general and disease-specific patient-reported outcome measurements: EuroQol 5 Domains Health-Related Quality of Life Questionnaire (EQ-5D-5L), Myasthenia Gravis Activities of Daily Living (MG-ADL), Myasthenia Gravis Quality of Life 15-item revised scale (MG-QoL-15r), Hospital Anxiety and Depression Scale (HADS) and Health Utilities Index III (HUI3). Patients were categorised by their self-assessed Myasthenia Gravis Foundation of America (MGFA) class (I-V).

RESULTS

Baseline results of 841 participants (mean age 47 years, 70% women) are reported . The distribution across the MGFA classes was: 13.9%, 31.0%, 38.1%, 15.5% and 1.6% for classes I-V. The MGFA class was a strong predictor of all aspects of HRQoL, measured with disease-specific and with generic instruments. The domains in which patients with MG most frequently mentioned problems were usual activities, anxiety and depression, tiredness, breathing and vision. The mean total MG-ADL Score was positively associated with increasing MGFA classes: 2.7, 4.4, 6.3 and 8.4 for MGFA classes I-IV. Mean baseline EQ-5D-5L utility was also associated with MGFA classes and was 0.817, 0.766, 0.648 and 0.530 for MGFA class I-IV.

CONCLUSIONS

MG has a large impact on key aspects of health and HRQoL. The impact of this disease increases substantially with increasing disease severity.

Measurement properties of the EQ-5D in populations with a mean age of ≥ 75 years: a systematic review

PURPOSE

Healthcare interventions for middle-old and oldest-old individuals are often (economically) evaluated using the EQ-5D to measure health-related quality of life (HrQoL). This requires sufficient measurement properties of the EQ-5D. Therefore, the current study aimed to systematically review studies assessing the measurement properties of the EQ-5D in this population.

METHODS

The databases PubMed, Cochrane library, Web of Science, Embase, and EconLit were searched for studies providing empirical evidence of reliability, validity, and/or responsiveness of the EQ-5D-3L and EQ-5D-5L in samples with a mean age ≥ 75 years. Studies were selected by two independent reviewers, and the methodological quality was assessed using the COSMIN Risk of Bias checklist. Results were rated against updated criteria for good measurement properties (sufficient, insufficient, inconsistent, indeterminate). The evidence was summarized, and the quality of evidence was graded using a modified GRADE approach.

RESULTS

For both EQ-5D versions, high-quality evidence for sufficient convergent validity was found. Known-groups validity was sufficient for the EQ-5D-5L (high-quality evidence), whereas the results were inconsistent for the EQ-5D-3L. Results regarding the reliability were inconsistent (EQ-5D-3L) or entirely lacking (EQ-5D-5L). Responsiveness based on correlations of change scores with instruments measuring related/similar constructs was insufficient for the EQ-5D-3L (high-quality evidence). For the EQ-5D-5L, the available evidence on responsiveness to change in (Hr)QoL instruments was limited.

CONCLUSION

Since the responsiveness of the EQ-5D in a population of middle-old and oldest-old individuals was questionable, either using additional instruments or considering the use of an alternative, more comprehensive instrument of (Hr)QoL might be advisable, especially for economic evaluations.

The assessment of psychometric properties for the subjective wellbeing-5 dimensions (SWB-5D) questionnaire in the general Dutch population

PURPOSE

Financial resources for health care are limited, so assessment of intervention effectiveness in terms of health in relation to its costs is important. Measuring health outcomes in cost-effectiveness analyses is usually done by health-related quality of life measures, like the EQ-5D. However, over the past decade, innovations on the conceptual level of health have evolved and novel approaches are rising such as the capability approach, subjective wellbeing, and Positive Health. This study assesses the psychometric properties of the subjective wellbeing-5 dimension (SWB-5D) outcome measure.

METHODS

A quantitative, cross-sectional study design was used to determine the concurrent and construct (convergent and known group) validity for the SWB-5D. Concurrent and convergent validity were estimated as correlations between the SWB-5D and the Dutch version of the EQ-5D, ICECAP-A, and PH-17. Assessment of known-groups validity was based on the variables illness, education, and the overall happiness (Cantril Ladder) and overall health scale (EQ-5D VAS).

RESULTS

A representative sample of 1016 respondents of the Dutch population completed an online questionnaire. The SWB-5D showed reasonable concurrent validity and showed good convergent and known-group validity. The SWB-5D had a lower ceiling effect compared to the EQ-5D and ICECAP-A.

CONCLUSION

Compared to traditional health measurement approaches, novel approaches are more focused on the mental and social pillars of health. The SWB-5D shows psychometric feasibility of comprehensive measurement of health, as indicated by a range of validity measures in a large representative sample of the Dutch population.

Extending the EQ-5D: the case for a complementary set of 4 psycho-social dimensions

OBJECTIVES

The EQ-5D is the most widely applied preference-based health-related quality of life measure. However, concerns have been raised that the existing dimensional structure lacks sufficient components of mental and social aspects of health. This study empirically explored the performance of a coherent set of four psycho-social bolt-ons: Vitality; Sleep; Personal relationships; and Social isolation.

METHODS

Cross-sectional surveys were conducted with online panel members from five countries (Australia, Canada, Norway, UK, US) (total N = 4786). Four bolt-ons were described using terms aligned with EQ nomenclature. Latent structures among all nine dimensions are studied using an exploratory factor analysis (EFA). The Shorrocks-Shapely decomposition analyses are conducted to illustrate the relative importance of the nine dimensions in explaining two outcome measures for health (EQ-VAS, satisfaction with health) and two for subjective well-being (the hedonic approach of global life satisfaction and an eudemonic item on meaningfulness). Sub-group analyses are performed on older adults (65 +) and socially disadvantaged groups.

RESULTS

Strength of correlations among four bolt-ons ranges from 0.34 to 0.49. As for their correlations with the EQ-5D dimensions, they are generally much less correlated with four physical health dimensions than with mental health dimensions (ranged from 0.21 to 0.50). The EFA identifies two latent factors. When explaining health, Vitality is the most important. When explaining subjective well-being, Social isolation is second most important, after Anxiety/depression.

CONCLUSION

We provide evidence that further complementing the current EQ-5D-5L health state classification system with a coherent set of four bolt-on dimensions that will fill its psycho-social gap.

A Qualitative Investigation of Older Adults' Conceptualization of Quality of Life and a Think-Aloud Content Validation of the EQ-5D-5L, SF-12v2, Warwick Edinburgh Mental Wellbeing Scale, and Office of National Statistics-4

OBJECTIVES

Old age is characterized by declining health, comorbidities, and increasing health and social care service use. Traditionally, patient-reported outcome measures (PROMs) including the EQ-5D-5L and SF-12v2 have focused on health. Nevertheless, aged care often aims to improve broader elements of quality of life (QoL), captured by well-being measures, such as the Warwick Edinburgh Mental Wellbeing Scale (WEMWBS) and Office of National Statistics-4 (ONS-4). This study investigates older adults' conceptualization of QoL and the content validity of the EQ-5D-5L, SF-12v2, WEMWBS, and ONS-4 in measuring their QoL.

METHODS

Qualitative cognitive think-aloud interviews were undertaken with older adults aged 75+, exploring their views on what was important to QoL and, for each measure, the relevance, acceptability, and interpretation of items; suitability of response options; and the comprehensiveness of the measure. Conceptualization of QoL was analyzed thematically and content validity using framework analysis.

RESULTS

Twenty interviews were undertaken. Older adults' conceptualization of QoL centered on health, ability to perform usual activities, social contact, and emotional functioning. Possible response shift was observed, as older adults assessed their health relative to lower health expectations at their age or to people in worse states. Participants questioned the relevance of negatively phrased mental items and often preferred the functioning-focused EQ-5D-5L to more subjective ONS-4 and WEMWBS items. Domains suggested to improve comprehensiveness included social contact, coping, security, dignity, and control.

CONCLUSIONS

These findings are useful to researchers developing new PROMs for older adults or for the developers of included PROMs considering permanently adapting or bolting-on domains to improve content validity in older adults.

Where do measures of health, social care and wellbeing fit within a wider measurement framework? Implications for the measurement of quality of life and the identification of bolt-ons

BACKGROUND

There is variability across studies in the dimensionality i.e., set of latent variables to which health, social care and wellbeing measures relate. This variability may impact the development of new measures and the identification of bolt-on dimensions. We examine the dimensionality of commonly used measures and identify a set of potential bolt-ons for the EQ-5D-5L.

METHODS

We used the OMS dataset, an online survey of health, social care and wellbeing measures in patients and members of the general public. A content analysis provided a theoretical framework for results interpretation. Quantitative analyses were based on a pool of 79 items from 7 measures. Confirmatory factor analysis was used to assess health, social care and wellbeing measures dimensionality and their contribution to quality of life. The relationship between EQ-5D-5L items and the identified factors was used for bolt-ons identification.

RESULTS

The dimensionality comprised of seven factors, namely physical functioning, psychological symptoms, energy/sleep, physical pain, social functioning, needs and satisfaction. Health measures covered five of the seven factors identified, wellbeing measures three and the social care measure one. A list of candidate bolt-on items for the EQ-5D-5L was presented e.g., cognition, energy, dignity.

CONCLUSIONS

This study provides evidence on the dimensionality of health, social care and wellbeing measures and presents a list of candidate bolt-ons for the EQ-5D-5L.

China Health Related Outcomes Measures (CHROME): Development of a New Generic Preference-Based Measure for the Chinese Population

BACKGROUND AND OBJECTIVES

Existing generic preference-based measures were all developed in Western countries. Evidence shows that the Chinese population may have different perceptions about health and health-related quality of life. This study aimed at developing a descriptive system of a new generic preference-based measure under the initiative of China Health Related Outcomes Measures (CHROME).

METHODS

Qualitative data were collected through semi-structured interviews conducted in-person or online. Respondents were recruited from both the general public and populations with chronic diseases. Open-ended questions about the respondent's perception of general health and important aspects of health-related quality of life were asked. Probing questions based on a systematic review of existing generic preference-based measures were also used. The framework analysis was used to synthesize the qualitative data. Candidate items for the descriptive system were selected following the ISPOR and COSMIN guidelines. Expert panel review and cognitive debriefings were conducted for further revisions.

RESULTS

Qualitative interviews were conducted among 68 respondents, with 48.5% male and a mean age of 47.8 years (range 18-81 years). In total, 1558 codes were identified and then aggregated to 31 sub-themes and corresponding six themes to inform the development of the initial version of the descriptive system. Feedback from the expert panel survey and meeting (n = 15) and the cognitive debriefing interviews (n = 30) was incorporated into the revised version of the measure. Finally, the generic version of CHROME (CHROME-G) included 12 items across six domains, namely, pain, fatigue, appetite, mobility, vision, hearing, sleeping, daily activities, depression, worry, memory, and social interactions. The descriptive system used a mix of four-level and five-level response options and a 7-day recall period.

CONCLUSIONS

The CHROME-G is the first generic preference-based measure to be developed based on the inputs from the Chinese populations.

The remarkably frequent use of EQ-5D in non-economic research

INTRODUCTION

EQ-5D is an instrument which has been utilized for a variety of purposes, including in health-economic appraisals as an input into quality-adjusted life year (QALY) calculations. Indeed, it is the most-widely applied instrument for health-economic appraisal worldwide, and is recommended for use in QALY calculations by many national Health Technology Assessment (HTA) agencies. There is also a growing body of evidence for its usefulness in a variety of settings other than economic appraisals, but such use has not been well-documented. This study addresses this issue and documents how EQ-5D has been applied in both the non-economic and economic contexts.

METHODS

The PubMed database was searched using the terms 'EQ-5D', 'EQ-5D AND cost', and 'EQ-5D AND cost AND QALY' from 1 January 1980 to 31 December 2019. We concentrated on 2019 publications for more detailed analyses. All the data collected for 2019 were downloaded and collected in EndNote. For 2019 only, we classified economic and non-economic use based on the inclusion of 'cost'. We also checked by manual inspection whether the search terms were suitable in correctly identifying economic and non-economic use. Variants of the non-economic use of EQ-5D were classified as follows: (a) as a quality of life outcome measure; (b) as a tool for methodological research; (c) methodological issues of EQ-5D itself; (d) comparisons with other quality of life questionnaires; (e) mapping studies; (f) value sets; (g) alongside costs but no QALY calculated; and (h) other.

RESULTS

The first publication found was from 1990. Up to and including 2019, 10,817 publications were identified, of which more than two in three did not contain any reference to costs or QALYs. In 2019, a total of 1409 manuscripts were identified, of which 239 were specifically for EQ-5D-5L.  Four hundred and seven (28.9%) included some form of 'costs' and 157 (11.1%) both 'costs' AND 'QALYs' terms. For EQ-5D-5L, the corresponding numbers were 104 (43.5%) and 29 (12.1%), respectively. After manually checking all the 1409 papers, three were duplicated records, which were omitted. In the remaining 1406 papers, only 40 (2.8%) contained the term 'cost', but not 'cost per QALY', and only 117 (8.3%) were identifiable as economic evaluations using the term 'cost per QALY'. Most non-economic use of EQ-5D was as a quality-of-life outcome measure (72.8%). Other applications were: as a tool for methodological research (6.7%); comparison studies (3.7%); EQ-5D methodological issues (3.5%); containing costs but not QALYs (2.8%); mapping (1.3%); value sets (0.4%); and other papers (0.4%).

CONCLUSIONS

The majority of the studies retrieved, covering a wide variety of research areas, reported upon the non-economic use of EQ-5D. Despite being the most-used instrument worldwide for QALY calculations, economic appraisal accounted for only a small, but important, part of published use.

A qualitative investigation of the relevance of skin irritation and self-confidence bolt-ons and their conceptual overlap with the EQ-5D in patients with psoriasis

Objectives

A number of bolt-ons have been proposed for the EQ-5D, including two psoriasis-specific bolt-ons, skin irritation and self-confidence. The study investigates and compares the relevance and comprehensiveness of these psoriasis-specific bolt-ons and the EQ-5D-5L and explores the potential conceptual overlaps between the existing five dimensions and the two bolt-ons.

Methods

Psoriasis patients were purposively sampled according to age and gender. Semi-structured interviews, where participants were asked to complete the EQ-5D-5L and the bolt-ons while thinking aloud, were conducted. Probes were used to investigate the thought processes of patients regarding the dimensions, wording, recall period and relevant concepts not captured by the EQ-5D-5L and bolt-ons. Data were analysed thematically. A focus group was used to confirm the findings.

Results

Overall, 16 patients completed the interviews. Sixteen and fifteen patients considered skin irritation and self-confidence relevant areas to describe psoriasis problems. Three patients considered itching a form of discomfort, and thus, pointed out a potential overlap between pain/discomfort and skin irritation. Twelve patients reported overall 10 general health- or psoriasis-related concepts that are not captured by the EQ-5D-5L, including itching, social relationships and sex life. Eleven patients reported that the recall period of the EQ-5D-5L might be subject to bias because of the daily or within-day fluctuations of their symptoms.

Conclusions

The skin irritation and self-confidence bolt-ons contribute to improve content validity of the EQ-5D-5L in patients with psoriasis. The qualitative approach taken in this study expands the existing methodological framework for the development and testing validity of bolt-ons for the EQ-5D.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11136-022-03141-y.

An EQ-5D-5L value set for Italy using videoconferencing interviews and feasibility of a new mode of administration

OBJECTIVES

To test the feasibility of using videoconferencing (VC) administered interviews and to derive an EQ-5D-5L value set for Italy.

METHODS

Preferences were collected using the EuroQol standardized valuation protocol (EQ-VT) administered via VC. Two valuation methods were employed, composite time trade-off (cTTO) and discrete choice experiment (DCE). Technical, organizational and protocol feasibility were tested in a pilot of 198 interviews. Upon positive assessment, data collection continued with a target sample of 1000-1200 participants including the pilot. Quality control (QC) procedures were employed to monitor interviewers' performance during the pilot and the data collection. Data were modelled using GLS, Tobit, Logit and Hybrid models with different error specifications. Monotonicity of coefficients, statistical significance, and theoretical considerations informed the model choice.

RESULTS

Dropouts and technical problems occurred in less than 5% of the 198 pilot interviews. Protocol compliance was demonstrated with significant improvements in QC parameters and limited interviewers' effects, for all interviewers. Overall, interviewers were satisfied with this mode of administration, highlighting it allows flexibility and efficient scheduling. Based on these results, VC was deemed as a feasible mode of administration. The study collected preferences for 1182 responders, including the pilot interviews. The demographic characteristics of the sample were representative of the Italian general population for age, gender and geographical macro-areas. The hybrid Tobit heteroscedastic model without constant estimated on the full sample (including pilot) was selected for the derivation of the value set. Values ranged from -0.571 for the worst health state (55555) to 1 for the best health state (11111). Pain/discomfort registered the largest decrement, followed by mobility, anxiety/depression, self-care, and usual activities. 523 health states were worse than dead.

CONCLUSIONS

VC is viable for the conduct of valuation interviews. The Italian value set for the EQ-5D-5L can be used for value determinations of health technologies.

Investigating the Added Value of the EQ-5D-5L With Two Bolt-On Items in Patients With Hemophilia

Objective: This study examined the impact of adding two condition-specific bolt-on items to the EQ-5D-5L and assessed their psychometric properties in patients with hemophilia.

Methods: The data were obtained from a nationwide cross-sectional online survey of patients with hemophilia in China. Self-reported and proxy-reported data were analyzed separately. Ceiling effect, informativity, and discriminatory power of the EQ-5D-5L with two bolt-on items, dignity (DG), and bleeding (BL), were examined. Spearman's rank correlation (rho) was used to assess the associations of the EQ-5D-5L and two bolt-on items with the Hemophilia Quality of Life Questionnaire for Adults (Haem-A-QoL) and SF-12. Multiple regression analysis was performed to evaluate the explained variance of the EQ-5D-5L and bolt-on items in predicting EQ-VAS scores.

Results: A total of 895 patients and 222 caregivers completed the questionnaire. The ceiling effect decreased from 1.9 to 0.6% and 5.9 to 0.9% when using the EQ-5D-5L and the EQ-5D-5L with two bolt-on items among participants with both self- and proxy-completed questionnaires. Both DG and BL were strongly correlated with Haem-A-QoL sum score [rho: DG = 0.64 (patient) vs. 0.66(proxy); BL = 0.49 (patient) vs. 0.31 (proxy)], SF-12 mental component [rho: DG = −0.36 (patient) vs. −0.41 (proxy); BL = −0.53 (patient) vs. −0.57(proxy)], and SF-12 physical component [rho: DG = −0.61 (patient) vs. −0.61 (proxy); BL = −0.35 (patient) vs. −0.39 (proxy)]. Known-group comparisons confirmed that the two bolt-on items had satisfactory discriminatory power. Multiple regression analysis indicated that adding two bolt-on items significantly increased the ability to predict EQ-VAS scores. The adjusted R² increased by 8.2 and 8.8% for reports completed by the patients or patients' proxy respondents, respectively.

Conclusion: Adding the DG and BL bolt-on items can increase performance on the EQ-5D-5L in patients with hemophilia. A future valuation study will be carried out.

Questionnaire Modifications and Alternative Scoring Methods of the Dermatology Life Quality Index: A Systematic Review

OBJECTIVES

Dermatology Life Quality index (DLQI) is the most widely used health-related quality of life questionnaire in dermatology. Little is known about existing questionnaire or scoring modifications of the DLQI. We aimed to systematically review, identify, and categorize all modified questionnaire versions and scoring methods of the DLQI.

METHODS

We performed a systematic literature search in PubMed, Web of Science, CINAHL, and PsychINFO. Methodologic quality and evidence of psychometric properties were assessed using the Consensus-Based Standards for the Selection of Health Measurement Instruments (COSMIN) and Terwee checklists.

RESULTS

The included 81 articles reported on 77 studies using 59 DLQI modifications. Modifications were used for a combined sample of 25 509 patients with 47 different diagnoses and symptoms from 28 countries. The most frequently studied diseases were psoriasis, hirsutism, acne, alopecia, and bromhidrosis. The modifications were categorized into the following nonmutually exclusive groups: bolt-ons or bolt-offs (48%), disease, symptom, and body part specifications (42%), changes in existing items (34%), scoring modifications (27%), recall period changes (19%), response scale modifications (15%), and illustrations (3%). The evidence concerning the quality of measurement properties was heterogeneous: 4 of 13 studies were rated positive on internal consistency, 1 of 3 on reliability, 3 of 5 on content validity, 9 of 22 on construct validity, 6 of 6 on criterion validity, and 1 of 1 on responsiveness.

CONCLUSION

An exceptionally large number of DLQI modifications have been used that may indicate an unmet need for adequate health-related quality of life instruments in dermatology. The psychometric overview of most questionnaire modifications is currently incomplete, and additional efforts are needed for proper validation.

Patient-reportedimpact of myasthenia gravis in the real world: protocol for a digital observational study (MyRealWorld MG)

INTRODUCTION

Myasthenia gravis (MG) is a rare, chronic, autoimmune disease, mediated by immunoglobulin G antibodies, which causes debilitating muscle weakness. As with most rare diseases, there is little patient-reported data with which to understand and address patient needs. This study explores the impact of MG in the real world from the patient perspective.

METHODS AND ANALYSIS

This is a 2-year prospective, observational, digital, longitudinal study of adults with MG, resident in the following countries: the USA, Japan, Germany, France, the UK, Italy, Spain, Canada and Belgium. The planned sample size is 2000. Recruitment will be community based, via patient advocacy groups, social media and word of mouth. Participants will use a smartphone application (app) to check eligibility, provide consent and contribute data. Planned data entry is as follows: (1) personal profile on enrollment-covering demographics, MG characteristics and previous care; (2) monthly event tracker-current treatments, healthcare visits, treatment-related adverse events, productivity losses; (3) monthly selection of validated generic and disease-specific patient-reported outcomes instruments: EQ-5D-5L, Myasthenia Gravis Activities of Daily Living, Myasthenia Gravis Quality of Life 15-item revised scale, Hospital Anxiety and Depression Scale and Health Utilities Index III. Analyses are planned for when the study has been running in most countries for approximately 6, 12, 18 and 24 months.

ETHICS AND DISSEMINATION

The study protocol has been reviewed and granted ethics approval by Salus IRB for participants resident in the following countries: Germany, the UK and the US. Local ethics approval is being sought for the following study countries: Belgium, Canada, France, Italy, Japan and Spain. Study results will be communicated to the public and participants via conference presentations and journal publications, as well as regular email, social media and in-application communication.

TRIAL REGISTRATION NUMBER

NCT04176211.

The Functional Assessment of Cancer Therapy Eight Dimension (FACT-8D), a Multi-Attribute Utility Instrument Derived From the Cancer-Specific FACT-General (FACT-G) Quality of Life Questionnaire: Development and Australian Value Set

OBJECTIVES

To develop a cancer-specific multi-attribute utility instrument derived from the Functional Assessment of Cancer Therapy - General (FACT-G) health-related quality of life (HRQL) questionnaire.

METHODS

We derived a descriptive system based on a subset of the 27-item FACT-G. Item selection was informed by psychometric analyses of existing FACT-G data (n = 6912) and by patient input (n = 82). We then conducted an online valuation survey, with participants recruited via an Australian general population online panel. A discrete choice experiment (DCE) was used, with attributes being the HRQL dimensions of the descriptive system and survival duration, and 16 choice-pairs per participant. Utility decrements were estimated with conditional logit and mixed logit modeling.

RESULTS

Eight HRQL dimensions were included in the descriptive system: pain, fatigue, nausea, sleep, work, social support, sadness, and future health worry; each with 5 levels. Of 1737 panel members who accessed the valuation survey, 1644 (95%) completed 1 or more DCE choice-pairs and were included in analyses. Utility decrements were generally monotonic; within each dimension, poorer HRQL levels generally had larger utility decrements. The largest utility decrements were for the highest levels of pain (-0.40) and nausea (-0.28). The worst health state had a utility of -0.54, considerably worse than dead.

CONCLUSIONS

A descriptive system and preference-based scoring approach were developed for the FACT-8D, a new cancer-specific multi-attribute utility instrument derived from the FACT-G. The Australian value set is the first of a series of country-specific value sets planned that can facilitate cost-utility analyses based on items from the FACT-G and related FACIT questionnaires containing FACT-G items.

Methods Used to Identify, Test, and Assess Impact on Preferences of Bolt-Ons: A Systematic Review

OBJECTIVES

The question of whether additional dimensions should be added to the EQ-5D, so-called bolt-ons, has been researched since the 1990s. Several candidate bolt-ons have been tested. The aim of this systematic review was to provide an overview of EQ-5D bolt-on studies, including the origin of possible suitable bolt-ons, their format, and methods that were used to examine their value.

METHODS

Studies were identified through database search and reference screening and assessed based on a set of inclusion criteria. All studies that investigated bolt-ons for the EQ-5D were eligible for inclusion. Two reviewers independently extracted information from all included studies on objectives, study design, EQ-5D version used, the investigated bolt-ons, methods used to achieve objectives, and outcomes.

RESULTS

Of 308 initially identified studies, 28 studies met the inclusion criteria. Of these studies, 3 identified potentially suitable bolt-on dimensions, 13 investigated the psychometric performance of EQ-5D + bolt-on(s), and 6 investigated the impact of the bolt-on on health state preferences. In total, 26 bolt-ons were identified, of which cognition was the most frequently mentioned. A wide variety of bolt-on identification methods, psychometric performance tests, and health state valuation methods were used in the included studies.

CONCLUSION

A range of bolt-on dimensions has been investigated using diverse methods. Guidelines are needed to standardize the wording of the bolt-on dimension and response options, evaluate minimal important gain of the bolt-on, and facilitate quality assessment of bolt-on studies. Subsequently, guidelines will facilitate decision making on whether or not to implement a bolt-on dimension to the EQ-5D.

Vignette-Based Utilities: Usefulness, Limitations, and Methodological Recommendations

Health technology assessment agencies often prefer that utilities used to calculate quality-adjusted life years in cost-utility analyses (CUAs) are derived using standardized methods, such as generic preference-based measures completed by patients in clinical trials. However, there are situations when no standardized approach is feasible or appropriate for a specific medical condition or treatment that must be represented in a CUA. When this occurs, vignette-based methods are often used to estimate utilities. A vignette (sometimes called a "scenario," "health state description," "health state vignette," or "health state") is a description of a health state that is valued in a preference elicitation task to obtain a utility estimate. This method is sometimes the only feasible way to estimate utilities representing a concept that is important for a CUA. Consequently, vignette-based studies continue to be conducted and published, with the resulting utilities used in economic models to inform decision making about healthcare resource allocation. Despite the potential impact of vignette-based utilities on medical decision making, there is no published guidance or review of this methodology. This article provides recommendations for researchers, health technology assessment reviewers, and policymakers who may be deciding whether to use vignette-based methods, designing a vignette study, using vignette-based utilities in a CUA, or evaluating a CUA that includes vignette-based utilities. Recommendations are provided on: (A) when to use vignette-based utilities, (B) methods for developing vignettes, (C) valuing vignettes, (D) use of vignette-based utilities in models, and (E) limitations of vignette methods.

The relation between EQ-5D and fatigue in a Dutch general population sample: an explorative study

Background

Fatigue negatively influences health-related quality of life. It is questionable whether fatigue is sufficiently covered by the EQ-5D. This study investigated whether fatigue is covered by the existing domains of the EQ-5D.

Methods

A Dutch general population sample completed the EQ-5D (3L and 5L version) and the Rivermead Post-Concussion Symptoms Questionnaire (RPQ), of which the fatigue item was used. Outcomes were compared between participants with and without a chronic health condition. Convergent validity was assessed, and multivariate regression analyses was used to predict the RPQ fatigue item from the EQ-5D-3L and EQ-5D-5L domains separately.

Results

3027 people completed the survey, of whom 52% had ≥ 1 chronic health condition. Fatigue was reported by 48% of the participants. Fatigue was moderately correlated to the EQ-5D domains ‘pain/discomfort’, ‘usual activities’, and ‘anxiety/depression’ for the 3L (r = 0.379–0.426) and 5L version (r = 0.411–0.469). For the 5L, also a moderate correlation with ‘mobility’ (r = 0.335) was observed. The remaining correlations were weak. All EQ-5D-3L and 5L domains except for ‘mobility’ were significantly associated with the RPQ fatigue item (unstandardized Beta = − 0.20–0.67; p < 0.01 to p = 0.04). Comparable outcomes were found for participants with and without ≥ 1 chronic health condition.

Conclusions

The extent to which fatigue is covered by the EQ-5D domains is small to moderate, with the EQ-5D-5L being slightly more sensitive to capture fatigue compared to the EQ-5D-3L. An extra fatigue item for the EQ-5D may add value, as fatigue is not fully captured by the existing domains, both in people with and without a chronic health condition.

Predicting quality of life in AMD patients-insights on the new NICE classification and on a bolt-on vision dimension for the EQ-5D

BACKGROUND/AIMS

Health-related quality of life (HRQoL) in age-related macular degeneration (AMD) is difficult to estimate as most generic tools underestimate vision. Our aim was to measure the effect of AMD on generic and visual quality of life and how it relates to handicap. We also aimed to validate the NG82 NICE AMD classification. Finally, we studied if a bolt-on visual domain increased the EQ-5D sensitivity to AMD.

PATIENTS AND METHODS

Ninety-six patients with AMD participated in this observational cross-sectional study. Visual (VF-14) and generic questionnaires (EQ-5D) with VIS, and the London handicap scale (LHS) was used to quantify HRQoL and handicap. ANOVA and regression analysis were used to identify significant associations.

RESULTS

Visual dysfunction in AMD has a significant effect in VF-14 (P < 0.001), LHS (p < 0.001), and EQ-5D (p = 0.015). The EQ-5D was less sensitive than the VF-14 and LHS and was not significantly correlated with the VIS bolt-on domain (p = 0.608). On the other hand, VIS was significantly associated with visual acuity (p < 0.001), AMD diagnosis (p = 0.005), VF-14 (p < 0.001), and LHS (p < 0.001). The new AMD classification was a good predictor of visual HRQoL and had an excellent association with visual acuity in the best eye.

CONCLUSION

This article shows that visual impairment is associated with lower HRQoL and with an increased handicap. It also suggests that a visual dimension may increase the EQ-5D sensitivity in AMD. There was a relationship between visual impairment and handicap with the items of the new NICE AMD classification, which supports its use.

Selecting Bolt-on Dimensions for the EQ-5D: Testing the Impact of Hearing, Sleep, Cognition, Energy, and Relationships on Preferences Using Pairwise Choices

BACKGROUND

Generic preference-based measures (GPBMs) such as the EQ-5D are valid across many conditions, but in some cases, "bolting on" additional dimensions may improve validity. The selection of "bolt-ons" has been based on the psychometric impact of individual dimensions, but preferences provide another important way to select them. This study aims to test the potential of using pairwise choices to inform the selection of bolt-ons for the EQ-5D-5L.

METHODS

General population preferences were collected using an online survey of 1040 UK residents. Three EQ-5D-5L health state pairs were selected based on pairs that had a 50:50 split in respondent preferences from a previous pairwise survey. Participants were presented with pairwise choices of EQ-5D-5L health states without and with bolt-ons of hearing, sleep, cognition, energy, and relationships, each added individually. Logistic models were used to assess the impact of bolt-ons, as well as bolt-ons at different severity levels, on the log odds of responders choosing between health states.

RESULTS

Preferences varied according to the bolt-ons and their severity level (only levels 1, 3, and 5 were used). Additions of bolt-ons at level 1 generally resulted in nonstatistically significant differences while additions of bolt-ons at level 3 and level 5 produced a negative and statistically significant impact on preferences for the health state with the bolt-on. At level 5, hearing had the largest impact, followed by cognition, relationships, energy, and sleep. At level 3, cognition produced the largest impact, followed by hearing and sleep with similar impacts, energy, and relationships. This ordering offers information for bolt-on selection, with hearing and cognition appearing as the most important. The weight placed on the different health problems is not constant across severity levels between bolt-ons.

CONCLUSIONS

Pairwise choices provide a cost-effective approach of generating information on preferences to support bolt-on selection.

Filling the psycho-social gap in the EQ-5D: the empirical support for four bolt-on dimensions

PURPOSE

The EQ-5D is the most widely applied generic preference-based measure (GPBM) of health-related quality of life (HRQoL). Much concern has been raised that its descriptive system is lacking psycho-social dimensions. A recent paper in this journal provided theoretical support for four dimensions to fill this gap. The current paper aims to provide empirical support for these suggested bolt-on dimensions to the EQ-5D.

METHODS

We use data from the comprehensive Multi-Instrument-Comparison (MIC) study. The four proposed bolt-on dimensions (Vitality, Sleep, Social Relationships, and Community Connectedness) were selected from the Assessment of Quality of Life (AQoL)-8D. We investigate the relative importance of these four dimensions as compared to the five EQ-5D-5L dimensions on explaining HRQoL (measured by a visual analogue scale; N = 7846) or global life satisfaction (measured by the Satisfaction With Life Scale; N = 8005), using the Shorrocks-Shapely decomposition analysis. Robustness analyses on Vitality was conducted using data from the United States National Health Measurement Study (NHMS) (N = 3812).

RESULTS

All five EQ-5D-5L dimensions and four bolt-on dimensions significantly explained the variance of HRQoL. Among them, Vitality was found to be the most important dimension with regard to the HRQoL (relative contribution based on the Shorrocks-Shapely decomposition of R2: 23.0%), followed by Usual Activities (15.1%). Self-Care was the least important dimension (relative contribution: 5.4%). As a comparison, when explaining global life satisfaction, Social Relationships was the most important dimension (relative contribution: 24.0%), followed by Anxiety/Depression (23.2%), while Self-Care remained the least important (relative contribution: 1.6%). The importance of the Vitality dimension in explaining HRQoL was supported in the robustness analysis using the NHMS data (relative contribution: 23.7%).

CONCLUSIONS

We provide empirical support for complementing the current EQ-5D-5L descriptive system with a coherent set of four bolt-on dimensions that will fill its psycho-social gap. Such an extended health state classification system would in particular be relevant for programme evaluations within the expanding fields of mental health and community care.

Assessing the construct validity and responsiveness of Preference-Based Measures (PBMs) in cataract surgery patients

PURPOSE

The validity and responsiveness of the EQ-5D-3L in visual conditions has been questioned, inspiring development of a vision 'bolt-on' domain (EQ-5D-3L + VIS). Developments in preference-based measures (PBM) also includes the EQ-5D-5L and the ICECAP-O capability wellbeing measure. This study aimed to examine the construct validity and responsiveness of the EQ-5D-3L, EQ-5D-5L, EQ-5D-3L + VIS and ICECAP-O in cataract surgery patients for the first time, to inform choice of PBM for economic evaluation in this population.

METHODS

The analyses used data from the UK Predict-CAT cataract surgery cohort study. PBMs and the Cat-PROM5 [a validated measure of cataract quality of life (QOL)] were completed before surgery and 4-8 weeks after. Construct validity was assessed using correlations and known-group differences evaluated using regression. Responsiveness was evaluated using effect sizes and analysis of variance to compare change scores between groups, defined by patient-reported and clinical outcomes.

RESULTS

The sample comprised 1315 patients at baseline. No PBMs were associated with visual acuity and only the ICECAP-O (Spearman's rs =  - 0.35), EQ-5D-3L + VIS (rs =  - 0.42) and EQ-5D-5L (Value Set for England rs =  - 0.31) correlated at least moderately with the Cat-PROM5. Effect sizes of change were consistently largest for the EQ-5D-3L + VIS (range 0.34-0.41), followed by the ICECAP-O (range 0.20-0.34). Results indicated no improvement in responsiveness using the EQ-5D-5L (range 0.13-0.16) compared to the EQ-5D-3L (range 0.17-0.20).

CONCLUSIONS

Whilst no PBMs comprehensively demonstrated evidence of construct validity and responsiveness in cataract surgery patients, the ICECAP-O was the most responsive generic PBM to improvements in QOL. Surprisingly the EQ-5D-5L was not more responsive than the EQ-5D-3L in this setting.

Factors contributing to the ceiling effect of the EQ-5D-5L: an analysis of patients with prostate cancer judged "no-problems"

Purpose

The goal of the present study was to determine factors related to a ceiling effect (CE) on the EQ-5D-5L among Japanese patients with prostate cancer (PC).

Methods

An existent cross-sectional observational study dataset was used. Patients were ≥ 20 years of age and diagnosed with PC. For CE determinants on the EQ-5D-5L, we excluded possible “full-health” patients flagged by the EQ-VAS (score = 100) and/or FACT-P (score = 156) instruments. We then divided them into binary variables: A CE group (EQ-5D-5L score = 1) and others (< 1). The associations between CE, sociodemographic and medical characteristics, and FACT-P subscale scores were examined using a multivariate LASSO selection followed by a binomial logistic regression analysis performed to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

Results

A total of 362 patients were analyzed. The LASSO selection variables, including all obtained variables, were as follows: age, palliative treatment, FACT-P physical well-being, and PC subscale score. Statistically significant variables predicting CE were palliative treatment (OR 0.23; 95% CI 0.09–0.60), physical well-being (OR 1.54; 95% CI 1.34–1.76), and PC subscale (OR 1.08; 95% CI 1.03–1.14).

Conclusions

This study revealed that palliative treatment and two FACT-P physical well-being and PC subscale scores were positively related to CE on the EQ-5D-5L. To our knowledge, this is the first study to examine predictors of CE on the EQ-5D-5L. The present results may be helpful for facilitating the consideration of “bolt-on” studies from the standpoint of PC patients.

A systematic review of the development and testing of additional dimensions for the EQ-5D descriptive system

Introduction: As the five dimensions of the EQ-5D might be insensitive to some populations or conditions, adding one or more specific 'bolt-on dimensions', to the EQ-5D may improve its validity and relevance for those groups. Various bolt-on dimensions have been identified and tested the effect on the psychometric performance and utility measurement. Therefore, this systematic review was to review all bolt-on dimensions and report the results of those two effects. Areas covered: Twelve studies were identified through PubMed, Scopus, and Web of Sciences from inception to January 2019. The bolt-on dimensions generally improved the EQ-5D's psychometric performance when compared with the standard version. However, evidence is lacking about the impact of bolt-on dimensions on responsiveness, reliability and known-groups validity. Evidence was also mixed for adding a sleep dimension, while interpersonal relationships did not promote a significant improvement on utility measurement. Expert opinion: Adding bolt-on dimensions could enhance the discriminative power and utility measurement of the EQ-5D; however, careful investigation of the sleep and interpersonal relationships is required since the evidence did not support a significant improvement. Further investigation of the identified bolt-on dimensions on all of the psychometric performance and the incremental utility scores derived from TTO is greatly encouraged.