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Objectives There has been a growing interest in the use of EQ-5D health outcomes measures in Latin America and the Caribbean. Population norms data provide a benchmark against which clinicians, researchers, and policy makers can compare the health status of patient, treatment, or demographic groups. This study aimed to provide EQ-5D-5L population norms for Belize. Methods The EQ-5D-5L questionnaire was included in a national survey in Belize in 2014. The survey also captured key demographic variables. EQ-5D-5L health states, EQ-5D visual analog scale (EQ VAS) scores, and EQ-5D-5L index values (based on the Trinidad and Tobago value set) were obtained for key demographic groups in Belize. Results A representative sample of 2078 respondents completed the survey. The mean index value, EQ VAS score, and ceiling level for Belize were 0.947, 82.6, and 67.8%, respectively. Similar to other Caribbean countries, Belizeans self-reported relatively high EQ VAS scores and ceiling levels compared with non-Caribbean regions. Men reported generally higher health status than women, health status declined as age rises, and the dimensions with the highest burden were pain/discomfort and mobility. Conclusions This study provides researchers and practitioners in Belize with tools to use EQ-5D-5L. Users can apply the EQ VAS scores and EQ-5D-5L states presented herein as reference values. Until an EQ-5D-5L value set is created for Belize, the Trinidad and Tobago index values can be applied to Belizean-reported EQ-5D-5L states, which can then be compared with the index values presented in this study.

Aim The EQ-5D is a generic measure of health that is widely applied for health economic and non-economic purposes. Population norms can be used to facilitate the interpretation of EQ-5D data. The objective of this study was to develop a set of pooled normative EQ-5D-3L values for the five largest European economies (EUR5). Methods EQ-5D-3L index values based on the time trade-off (TTO) were available for all EUR5 countries (n = 21,425): France, Germany, Italy, Spain, and the United Kingdom (UK). Country-specific data sets were aggregated and weighted to facilitate the derivation of norms for gender and age groups. Analyses included equal weighting and weighting by population and economy size. Norms were also calculated using the European visual analog scale-based value set (European VAS), the EQ VAS and separately by dimension. Results Pooled mean (SD) population weighted TTO values for males/females were 0.967 (0.122)/0.959 (0.118) for ages 18–24; 0.965 (0.096)/0.954 (0.117) for ages 25–34; 0.943 (0.165)/0.936 (0.169) for ages 35–44; 0.934 (0.150)/0.921 (0.157) for ages 45–54; 0.896 (0.188)/0.875 (0.197) for ages 55–64; 0.900 (0.158)/0.839 (0.218) for ages 65–74; and 0.830 (0.234)/0.756 (0.291) for ages 75 and older. Mean values decreased and variance increased with age; females had slightly lower mean values than males across all age bands. The unequal weighting approaches produced similar point estimates with smaller variances. Mean values for the European VAS were slightly lower than those for the TTO-based index. Discussion Normative EQ-5D-3L values can be used to benchmark the outcomes of treated patients against the health of the general population. EUR5 norms may be useful in research applications inferring to Europe or the European Union as a whole, particularly when sample size precludes analysis at the country level.

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.

Introduction Health-related quality of life (HRQL) is an important outcome in burn care and research. An advantage of a generic HRQL instrument, like the EQ-5D, is that it enables comparison of outcomes with other conditions and the general population. However, the downside is that it does not include burn specific domains, like scar issues or itching. Adding extra items to a generic instrument might overcome this issue. This study explored the potential and added value of extending the EQ-5D-5L with a burn-specific item, using a itching item as an example. Methods The EQ-5D-5L and the Patient and Observer Scar Assessment Scale (POSAS) was completed by adult patients 5–7 years after injury. A separate POSAS itching item was used to study the added value of an itching item for the EQ-5D-5L. The EQ-5D-5L + Itching was created by adding the POSAS itching item to the EQ-5D-5L. Five psychometric properties were compared between EQ-5D-5L and EQ-5D-5L + Itching: distribution (e.g. ceiling), informativity cf. Shannon’s indices, convergent validity, dimension dependency, and explanatory power respectively. Results A total of 243 patients were included, of whom 49% reported any itching on the POSAS. Adding an itching item to the EQ-5D-5L decreased the ceiling effect, and resulted in increased absolute informativity (H’ = 4.76 vs. H’ = 3.64) and relative informativity (J’ = 0.34 vs. J’ = 0.31). The extra itching item decreased the convergent validity (Spearman’s rank correlation coefficient = −0.51 vs. −0.59). Mutual dependency of dimensions existed, showing that all other items were dominant over the itching item. Adding the itching item to the standard EQ-5D-5L barely improved explanatory power (49.3% vs. 49.0%). Conclusions PThe present study showed adding a burn-specific item to the EQ-5D-5L is possible and has potential. However, 5 to 7 years after injury, adding an itching item to the EQ-5D-5L provides little additional information; the gain in terms of added value is relatively small. Apart from instances where itching information is specifically needed, a strong case is not present for adding an itching item to the EQ-5D-5L for long-term (>5 yr after burns) HRQL assessment in burn patients. In early time periods after burn, the added value might be greater and we recommend exploring this potential in future studies, ideally on multiple timepoints after burn.

Background Health fluctuations even within a single day are typical in multiple sclerosis (MS), but are not captured by widely used questionnaires like the EQ-5D-5L. This exploratory study aimed to develop an ambulatory assessment (AA) version of the EQ-5D-5L (EQ-5D-AA) where patients rate their health on mobile phones multiple times per day over several days, and to assess its feasibility and face validity. Methods An initial EQ-5D-AA version was based on two patient focus groups. It was then tested and continuously developed in an iterative process: patients completed it over several days, followed by debriefing interviews. Findings were used to refine the EQ-5D-AA, with the resulting version being tested by the subsequent wave of patients until participants declared no need for changes anymore. Before and after the AA period, participants completed the standard paper-based EQ-5D-5L asking about ‘today’. Results Focus group participants reported that their impairments often fluctuated between and within days. They regarded an AA with three assessments per day over seven days most appropriate; assessment should be retrospective to the previous assessment, but not all items should be assessed at each time point. Four waves of AA testing were conducted. Thirteen out of the 17 participants preferred the AA over standard assessment as they regarded it more informative, but not too burdensome. Conclusion The newly developed one-week AA of the EQ-5D-5L captures within-day and day-to-day health fluctuations in people with MS. From the patients’ perspective, it is a feasible and face valid way to provide important information beyond what is captured by the standard EQ-5D-5L.

PurposeAlthough the EQ-5D has a long history of use in a wide range of populations, the newer five-level version (EQ-5D-5L) has not yet had such extensive experience. This systematic review summarizes the available published scientific evidence on the psychometric properties of the EQ-5D-5L.MethodsPre-determined key words and exclusion criteria were used to systematically search publications from 2011 to 2019. Information on study characteristics and psychometric properties were extracted: specifically, EQ-5D-5L distribution (including ceiling and floor), missing values, reliability (test–retest), validity (convergent, known-groups, discriminate) and responsiveness (distribution, anchor-based). EQ-5D-5L index value means, ceiling and correlation coefficients (convergent validity) were pooled across the studies using random-effects models.ResultsOf the 889 identified publications, 99 were included for review, representing 32 countries. Musculoskeletal/orthopedic problems and cancer (n = 8 each) were most often studied. Most papers found missing values (17 of 17 papers) and floor effects (43 of 48 papers) to be unproblematic. While the index was found to be reliable (9 of 9 papers), individual dimensions exhibited instability over time. Index values and dimensions demonstrated moderate to strong correlations with global health measures, other multi-attribute utility instruments, physical/functional health, pain, activities of daily living, and clinical/biological measures. The instrument was not correlated with life satisfaction and cognition/communication measures. Responsiveness was addressed by 15 studies, finding moderate effect sizes when confined to studied subgroups with improvements in health.ConclusionsThe EQ-5D-5L exhibits excellent psychometric properties across a broad range of populations, conditions and settings. Rigorous exploration of its responsiveness is needed.

Purpose This study investigated the psychometric yield of extension of the EQ-5D-5L with a cognitive domain (EQ-5D+C) in a mixed cohort of trauma patients with repeated data. Methods A stratified sample of patients that presented at the emergency department filled out a follow-up survey 6 and 12 months after trauma. The surveys included the EQ-5D-5L+C, EQ-VAS, and the impact of events scale-revised (IES-R), a validated post-traumatic stress disorder (PTSD) self-assessment scale. Generally, results of the EQ-5D and EQ-5D+C were compared. Psychometrics included the following: distributional features (ceiling/floor effects), discriminatory performance, convergent validity with the EQ-VAS as reference, and responsiveness to change. Psychometric properties were compared between predefined subgroups based on conditions with cognitive impact (Traumatic Brain Injury (TBI)/PTSD). Results In total, 1799 trauma patients responded 6 and 12 months after trauma, including 107 respondents with PTSD, and 273 with TBI. Six months post-trauma, ceiling of the EQ-5D (26.3%) was reduced with 2.2% with the additional cognitive domain. Using EQ-VAS as reference, convergent validity increased slightly with the addition of the cognitive domain: correlation increasing from 0.651 to 0.664. Cognitive level was found to slightly improve over time in TBI (delta: 0.04) and PTSD patients (delta: 0.05), while (almost) no change was found in patients without TBI and PTSD. Conclusion Adding a cognitive domain to the EQ-5D-5L slightly improved measurement properties and better captured change in health status for trauma patients with TBI and PTSD. Inclusion of the cognitive domain in the EQ-5D-5L when measuring in populations with cognitive problems should be considered.

Introduction The EQ-5D is frequently used to understand the development of health-related quality of life (HRQL) following injury. However, the lack of a cognition dimension is generally felt as disadvantageous as many injuries involve cognitive effects. We aimed to assess the added value of a cognitive dimension in a cohort of injury patients. Methods We analyzed EQ-5D-3L extended with cognition (EQ-5D + C) dimension responses of 5346 adult injury patients. We studied dimension dependency, assessed the additional effect of the cognitive dimension on the EQ-VAS, and, using the EQ-VAS as a dependent variable, determined the impact of EQ-5D and EQ-5D + C attributes in multivariate regression analyses. Results Extreme cognitive problems combined with no problems on other dimensions are uncommon, whereas severe problems on other dimensions frequently occur without cognitive problems. The EQ-VAS significantly decreased when cognitive problems emerged. Univariate regression analyses indicated that all EQ-5D + C dimensions were significantly associated with the EQ-VAS. Exploratory analyses showed that using any set of five of the six EQ-5D + C dimensions resulted in almost identical explained variance, and adding the remaining 6th dimension resulted in a similar additional impact. Conclusions The addition of the cognition dimension increased the explanatory power of the EQ-5D-3L. Although the increase in explanatory power was relatively small after the cognition dimension was added, the decrease of HRQoL (measured with the EQ-VAS) resulting from cognitive problems was comparable to the decreases resulting from other EQ-5D dimensions.

Background The EQ-5D instrument is increasingly used in clinical and resource allocation decision making in developed and developing countries. EQ-5D valuation and population norms studies have been undertaken for Trinidad and Tobago, however no population norms or value sets have been generated for the other Caribbean countries. The aims of this study were to provide population norms for Barbados and Jamaica, and to develop a set of population norms that could be used by the other English-speaking Caribbean countries. Methods The EQ-5D-5L self-reported health questionnaire was included in surveys of representative samples of adults in Barbados and adults in Jamaica in 2013. EQ-5D health states, mean EQ VAS scores and mean EQ-5D-5L index values (using the Trinidad and Tobago value set) were calculated for demographic groups in both countries based on 2347 respondents from Barbados and 1423 from Jamaica. A set of ‘Caribbean’ norms were developed by combining the Barbados and Jamaica data with norms recently published for Trinidad and Tobago. Results Data were obtained for 2347 and 1423 respondents in Barbados and Jamaica respectively. The mean index and EQ VAS values were 0.943 and 81.9 for Barbados, and 0.948 and 87.8 for Jamaica. The health states most commonly observed in the two countries were similar. Generally the demographic patterns of self-reported health were consistent with those found in other studies. Some differences between the countries were observed in the patterns of rates of reporting problems on the EQ-5D dimensions among age-gender groups specifically for anxiety/depression and pain/discomfort Conclusion This study has produced a set of EQ-5D population norms that can be used as base-line values in clinical and clinico-economic analyses for Barbados and Jamaica and for the English-Speaking Caribbean region.

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 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.

Objectives The EQ-5D-3L and EQ-5D-5L instruments have been used in studies of patient and demographic groups in Colombia, but to date there are no 5L population norms. This study aimed to produce a set of EQ-5D-5L population norms for Colombia and to see what insights into health inequality in Colombia can be discerned from these norms. Methods The EQ-5D-5L self-reported health questionnaire was included in a survey of a representative sample of 3400 adults aged 18 to 64 in Colombia. EQ-5D-5L states, mean EQ VAS, and index values were obtained by sex, age, education, income group, ethnicity, residence, employment status, health insurance status, and household size. EQ-5D-5L index values from Uruguay were used. Regression models were used to investigate inequality. Results The mean EQ VAS value was 85.3, the mean index value was 0.953, and 52.2% of the sample reported being in state 11111. Self-reported health was higher for men, declined in higher age groups, and was lower for lower-income and education groups. The EQ-5D-5L instrument was observed to be more sensitive than the EQ-5D-3L instrument in Colombia. The dimensions with the highest prevalence of reported problems were anxiety/depression and pain/discomfort. The main drivers of inequality were age, sex, income, and education. Conclusions The population norms developed in this study can be used as baseline values for future studies of patient or treatment groups, and for investigations into the health of specific demographic groups.

Background The Swedish National Quality Registries (NQRs) contain individual-level health care data for specific patient populations, or patients receiving specific interventions. Approximately 90% of the 105 Swedish NQRs include any patient-reported outcome measure, with EQ-5D being the most common. As there has been no general overview of EQ-5D data within the NQRs, this study fills a knowledge gap by reporting how the data are collected, presented, and used at different levels of the Swedish health care system. Methods All 46 NQRs with a license for the use of EQ-5D were included. Information was retrieved from the registries’ annual reports or from websites, using a template that was subsequently sent to each registry for completion and confirmation. If considered necessary, the contact was followed-up with an interview, either in-person or over the telephone. The uses of EQ-5D were categorised as denoting usage for follow-up, decision-making, or quality improvement in Swedish health care. Results In total, 41 of the 46 licensed registries reported collection of EQ-5D data. EQ-5D is most commonly collected within registries related to the musculoskeletal system, but it has a wide application also in other disease areas. Thirty-six registries provide EQ-5D results to patients, clinicians, or other decision-makers. Twenty-two of the registries reported that EQ-5D data are being used for follow-up, decision-making or quality improvement. The registries most commonly reported use of data for assessing interventions, and in quality indicators to follow-up the quality of care at a national level. Conclusion Collection and use of EQ-5D data vary across the Swedish NQRs, which may partly be accounted for by the different purposes of the registries. The provided examples of use illustrate how EQ-5D data can inform decisions at different levels of the health care system. However, there is potential for improving the use of EQ-5D data.

Objective: This study describes the first empirical head-to-head comparison of EQ-5D-3L (3L) and EQ-5D-5L (5L) value sets for multiple countries. Methods: A large multinational dataset, including 3L and 5L data for eight patient groups and a student cohort, was used to compare 3L versus 5L value sets for Canada, China, England/UK (5L/3L, respectively), Japan, The Netherlands, South Korea and Spain. We used distributional analyses and two methods exploring discriminatory power: relative efficiency as assessed by the F statistic, and an area under the curve for the receiver-operating characteristics approach. Differences in outcomes were explored by separating descriptive system effects from valuation effects, and by exploring distributional location effects. Results: In terms of distributional evenness, efficiency of scale use and the face validity of the resulting distributions, 5L was superior, leading to an increase in sensitivity and precision in health status measurement. When compared with 5L, 3L systematically overestimated health problems and consequently underestimated utilities. This led to bias, i.e. over- or underestimations of discriminatory power. Conclusion: We conclude that 5L provides more precise measurement at individual and group levels, both in terms of descriptive system data and utilities. The increased sensitivity and precision of 5L is likely to be generalisable to longitudinal studies, such as in intervention designs. Hence, we recommend the use of the 5L across applications, including economic evaluation, clinical and public health studies. The evaluative framework proved to be useful in assessing preference-based instruments and might be useful for future work in the development of descriptive systems or health classifications.

© 2018, The Author(s). Background: Three EQ-5D value sets (EQ-5D-3L, crosswalk, and EQ-5D-5L) are now available for cost-utility analysis in the UK and/or England. The value sets’ characteristics differ, and it is important to assess the implications of these differences. Objective: The aim of this paper is to compare the three value sets. Methods: We carried out analysis comparing the predicted values from each value set, and investigated how differences in health on the descriptive system is reflected in the utility score by assessing the value of adjacent states. We also assessed differences in values using data from patients who completed both EQ-5D-3L and EQ-5D-5L. Results: The distribution of the value sets systematically differed. EQ-5D-5L values were higher than EQ-5D-3L/crosswalk values. The overall range and difference between adjacent states was smaller. In the patient data, the EQ-5D-5L produced higher values across all conditions and there was some evidence that the value sets rank different health conditions in a similar severity order. Conclusions: There are important differences between the value sets. Due to the smaller range of EQ-5D-5L values, the possible change in quality-adjusted life years (QALYs) might be reduced, but they will apply to both control and intervention groups, and will depend on whether the gain is in quality of life, survival, or both. The increased sensitivity of EQ-5D-5L may also favour QALY gains even if the changes in utility are smaller. Further work should assess the impact of the different value sets on cost effectiveness by repeating the analysis on clinical trial data.

Background The EQ-5D domain pain/discomfort (PD) uses one item to capture pain and other aspects of discomfort, like itching. This study explored how pain, itching and the EQ-5D-5L PD domain relate to each other in a sample of burn patients. Methods Adult burn patients completed the EQ-5D-5L and the Patient and Observer Scar Assessment Scale (POSAS) 5–7 years after sustaining their injury. The POSAS includes a separate pain and an itching item. Spearman’s correlation coefficient established the association between the EQ-5D-5L PD and the POSAS pain and itching item. With multivariable regression analysis the linear association between the POSAS pain and itching item and EQ-5D-5L PD domain was tested. Results Data from 245 patients were included. Mean EQ-5D-5L index value was 0.87 and 39.2% reported at least slight problems on the EQ-5D-5L PD domain. Most patients gave corresponding answers on the EQ-5D-5L PD domain and on the POSAS pain (73%) and itching (70%) item. Spearman correlation coefficients of the EQ-5D-5L PD domain with the POSAS pain and itching were 0.468 (p p p = 0.076) and 0.408 (p = 0.001), respectively. POSAS pain (unstandardized Beta = 0.14) and POSAS itching (unstandardized Beta = 0.08) were significantly associated with EQ-5D-5L PD domain (p Conclusions Our findings indicate that, in a sample of burn patients, pain and itching are captured by the broader EQ-5D-5L PD domain. The EQ-5D-5L PD domain can thus be used to assess pain and itching in relation to HRQL, but the POSAS pain and itching items are more sensitive. The EQ-5D-5L is, however, no replacement of the POSAS when the POSAS is used for its primary aim; assessment of scar quality. Trial registration Netherlands Trial Register (NTR6407).

(1) To evaluate the effect of adding a vision dimension (‘bolt-on’) to the 5-level EQ-5D (EQ-5D-5L) and 3-level EQ-5D (EQ-5D-3L) on their responsiveness, and (2) to compare the responsiveness of a vision ‘bolt-on’ EQ-5D-3L (EQ-5D-3L + V) with SF-6D and Health Utilities Index Mark 3 (HUI3) to the benefit of cataract surgery. Sixty-three patients were assessed before and after their cataract surgery using the EQ-5D-3L, EQ-5D-5L, SF-6D, HUI3, as well as a 3-level and a 5-level vision dimension. Preference-based indices were calculated using available value sets for EQ-5D-3L, EQ-5D-3L + V, EQ-5D-5L, SF-6D, and HUI3, and non-preference-based indices were calculated using the sum-score method for EQ-5D-5L and EQ-5D-5L + V (vision bolt-on EQ-5D-5L). Responsiveness was assessed using the standardized response mean (SRM) and F-statistic. Among preference-based indices, mean changes from pre to post-surgery in EQ-5D-3L + V and EQ-5D-3L indices were 0.031 and 0.018, respectively. The mean changes for EQ-5D-5L, SF-6D and HUI3 indices were 0.020, 0.012 and 0.105, respectively. The SRM (F-statistic) for EQ-5D-3L + V and EQ-5D-3L indices were 0.458 (13.2) and 0.098 (0.6), respectively. The responsiveness of EQ-5D-3L + V was better than EQ-5D-5L, SF-6D; the responsiveness of HUI3 was better than all other measures. Using non-preference-based indices, mean change for EQ-5D-5L + V and EQ-5D-5L were 0.067 and 0.017, respectively. The corresponding SRM (F-statistic) were 0.709 (31.7) and 0.295 (5.4). Preliminary evidence from our study suggests that a vision ‘bolt-on’ may increase the responsiveness of EQ-5D-3L and EQ-5D-5L to change in health outcomes experienced by patients undergoing cataract surgery. In absence of the preference-based vision bolt-on EQ-5D-5L index, HUI3 was the most responsive measure.

Background Health states defined by multiattribute instruments such as the EuroQol five-dimensional questionnaire with five response levels (EQ-5D-5L) can be valued using time trade-off (TTO) or discrete choice experiment (DCE) methods. A key feature of the tasks is the order in which the health state dimensions are presented. Respondents may use various heuristics to complete the tasks, and therefore the order of the dimensions may impact on the importance assigned to particular states. Objective To assess the impact of different EQ-5D-5L dimension orders on health state values. Methods Preferences for EQ-5D-5L health states were elicited from a broadly representative sample of members of the UK general public. Respondents valued EQ-5D-5L health states using TTO and DCE methods across one of three dimension orderings via face-to-face computer-assisted personal interviews. Differences in mean values and the size of the health dimension coefficients across the arms were compared using difference testing and regression analyses. Results Descriptive analysis suggested some differences between the mean TTO health state values across the different dimension orderings, but these were not systematic. Regression analysis suggested that the magnitude of the dimension coefficients differs across the different dimension orderings (for both TTO and DCE), but there was no clear pattern. Conclusions There is some evidence that the order in which the dimensions are presented impacts on the coefficients, which may impact on the health state values provided. The order of dimensions is a key consideration in the design of health state valuation studies.

It is not clear whether 5-level EQ-5D (EQ-5D-5L) utilities based on recently developed value sets are more responsive than 3-level EQ-5D (EQ-5D-3L) utilities. The study aims were to compare (1) the responsiveness of EQ-5D-5L and EQ-5D-3L utilities and (2) the responsiveness of these utilities with the Short Form–6 Dimension (SF-6D) and Health Utilities Index Mark 3 (HUI3) utilities to the treatment benefit of cataract surgery. A total of 148 patients were interviewed before and after their cataract surgery using EQ-5D-3L, EQ-5D-5L, SF-6D, and HUI3. Responsiveness was assessed for all measures using the mean change (post-treatment—pre-treatment), standardized effect size (SES), standardized response mean (SRM), and F-statistic. Using the Singapore value sets, mean change for EQ-5D-3L and EQ-5D-5L utilities was 0.016 and 0.028, SES was 0.097 and 0.199; SRM was 0.091 and 0.196; and F-statistic was 1.2 and 5.7, respectively. Similar trends were observed using the UK/England EQ-5D value sets, although the magnitude was slightly smaller. The mean change, SES, SRM and F-statistics for SF-6D (UK value set) were 0.020, 0.234, 0.249, and 9.2, respectively. The values of mean change, SES, SRM and F-statistics for HUI3 (Canada value set) were 0.080, 0.472, 0.474, and 33.3, respectively. The EQ-5D-5L utilities tend to be more responsive than the EQ-5D-3L utilities to treatment benefits of cataract surgery. The HUI3 utilities are more responsive than both the EQ-5D-5L and SF-6D, and SF-6D utilities may be slightly more responsive than the EQ-5D-5L for assessing patients undergoing cataract surgery.

Purpose This study investigated the psychometric gain, if any, from the extension of the EQ-5D with a cognition bolt-on (EQ-5D + C) in a large cohort injury patients with and without traumatic brain injury (TBI). Methods Hospitalized adult injury patients filled out a survey 1 month after initial admission. The survey included the EQ-5D-3L, the cognition bolt-on item in EQ-5D format, and the visual analogue scale (EQ-VAS). We compared ceiling and other distributional effects between EQ-5D and EQ-5D + C and TBI and non-TBI group, and assessed convergent validity using the predictive association with EQ-VAS. Also, we assessed explanatory power using regression analysis, and classification efficiency using Shannon indices. Results In total, 715 TBI patients and 1978 non-TBI patients filled out the EQ-5D + C and EQ-VAS. Perfect health was reported by 7.9% (N = 214) on the EQ-5D, and 7.3% (N = 197) on the EQ-5D + C. Convergent validity was highest for EQ-5D + C in the TBI group (Spearman’s rank correlation coefficient = − 0.736) and lowest for EQ-5D in the non-TBI group (Spearman’s rank correlation coefficient = − 0.652). For both TBI and non-TBI groups, the explanatory power of EQ-5D + C was slightly higher than of EQ-5D (R2 = 0.56 vs. 0.53 for TBI; R2 = 0.47 vs. 0.45 for non-TBI). Absolute classification efficiency was higher for EQ-5D + C than for EQ-5D in both TBI groups, whereas relative classification efficiency was similar. Conclusions Psychometric performance in general of both the EQ-5D and EQ-5D + C was better in TBI patients. Adding a cognitive bolt-on slightly improved the psychometric performance of the EQ-5D-3L.

This study provides EQ-5D population norms for 20 countries (N = 163,838), which can be used to compare profiles for patients with specific conditions with data for the average person in the general population in a similar age and/or gender group. Descriptive EQ-5D data are provided for the total population, by gender and by seven age groups. Provided index values are based on European VAS for all countries, based on TTO for 11 countries and based on VAS for 10 countries. Important differences exist in EQ-5D reported health status across countries after standardizing for population structure. Self-reported health according to all five dimensions and EQ VAS generally decreased with increasing age and was lower for females. Mean self-rated EQ VAS scores varied from 70.4 to 83.3 in the total population by country. The prior living standards (GDP per capita) in the countries studied are correlated most with the EQ VAS scores (0.58), while unemployment appeared to be significantly correlated in people over the age of 45 only. A country's expenditure on health care correlated moderately with higher ratings on the EQ VAS (0.55). EQ-5D norms can be used as reference data to assess the burden of disease of patients with specific conditions. Such information, in turn, can inform policy-making and assist in setting priorities in health care. This research was funded by the EuroQol Research Foundation under Grant no. 201108.

Background Three EQ-5D value sets (EQ-5D-3L, crosswalk, and EQ-5D-5L) are now available for cost-utility analysis in the UK and/or England. The value sets’ characteristics differ, and it is important to assess the implications of these differences. Objective The aim of this paper is to compare the three value sets. Methods We carried out analysis comparing the predicted values from each value set, and investigated how differences in health on the descriptive system is reflected in the utility score by assessing the value of adjacent states. We also assessed differences in values using data from patients who completed both EQ-5D-3L and EQ-5D-5L. Results The distribution of the value sets systematically differed. EQ-5D-5L values were higher than EQ-5D-3L/crosswalk values. The overall range and difference between adjacent states was smaller. In the patient data, the EQ-5D-5L produced higher values across all conditions and there was some evidence that the value sets rank different health conditions in a similar severity order. Conclusions There are important differences between the value sets. Due to the smaller range of EQ-5D-5L values, the possible change in quality-adjusted life years (QALYs) might be reduced, but they will apply to both control and intervention groups, and will depend on whether the gain is in quality of life, survival, or both. The increased sensitivity of EQ-5D-5L may also favour QALY gains even if the changes in utility are smaller. Further work should assess the impact of the different value sets on cost effectiveness by repeating the analysis on clinical trial data.

Background Since the introduction of the five-level version of the EQ-5D (5L), many studies have comparatively investigated the measurement properties of the original three-level version (3L) with the 5L version. Objective The aim of this study was to consolidate the available evidence on the performance of both instruments. Methods A systematic literature search of studies in the English and German languages was conducted (2007–January 2018) using the PubMed, EMBASE, and PsycINFO (EBSCO) databases, as well as the EuroQol Research Foundation website. Data were extracted and assessed on missing values, distributional properties, informativity indices (Shannon’s H′ and J′), inconsistencies, responsiveness, and test–retest reliability. Results Twenty-four studies were included in the review. Missing values and floor effects (percentage reporting the worst health state) were found to be negligible for both 3L and 5L (

© 2017, Springer International Publishing Switzerland. Introduction: The EQ-5D is a standardised instrument designed for use as a generic measure of health outcome. It was (and is) intended to provide information about a ‘common core’ of dimensions known to be relevant across a range of conditions; however, the five dimensions may not fully capture the health-related impacts of certain conditions. This study analyses the views of the UK general public about important aspects of health considered to be missing from the instrument. Methods: Survey respondents were asked whether there are any aspects of health they consider to be important but are not captured by the EQ-5D, and, if so, what these aspects are. The responses (text comments) were analysed using content analysis with analyst triangulation. Data were collected from a broadly representative sample of the general public via a paper questionnaire administered as part of face-to-face interviews. Results: Data are available for 436 respondents, 179 of whom suggested aspects of health they considered important but not captured by the five EQ-5D dimensions. These were organised into 22 themes. Sensory deprivation and mental health were the health aspects most commonly mentioned by respondents. Conclusions: Respondents identified several important aspects of health that are not covered by the EQ-5D descriptive system. This study can provide the basis for more detailed qualitative and quantitative research—in particular to examine the views of different patient groups—to inform further review of the EQ-5D descriptive system. The results also have implications for the sensitivity of other generic measures.

Purpose To assess EQ-5D-5L (5L) validity in patients with acute stroke, in comparison with EQ-5D-3L (3L). Methods Cross-sectional study of 408 patients during index hospitalization. We compared 5L and 3L in terms of feasibility, frequency of unique health states, ceiling effect and discriminatory power (informativity). We assessed construct validity in terms of known-groups validity and convergent validity of 5L dimensions with other stroke outcome measures. Results The overall proportion of patients with acute stroke reporting ‘no problems’ with 3L—6.1 % was further reduced to 5.6 % with 5L (relative reduction of 8.2 %). The highest improvement in relative discriminatory power, when moving from 3L to 5L, was noticed in pain/discomfort and anxiety/depression dimensions (Shannon Evenness Index 0.91 for both 5L dimensions; relative increase 34.4 and 29.1 %, respectively). Known-groups validity tests confirmed prior hypotheses: Health state utilities were lower in following subpopulations—females, patients with high modified Rankin Scale (mRS) score, low Barthel Index (BI) or VAS score, patients with subarachnoid hemorrhage or intracerebral hemorrhage, and when proxy respondent was used. Convergence of EQ-5D-5L dimensions with mRS, BI and EQ VAS was improved or at least the same as for 3L dimensions. Conclusions Results support the validity of the EQ-5D-5L descriptive system as a generic health outcome measure in patients with acute stroke, demonstrating some psychometric advantages in comparison with EQ-5D-3L.

The EQ-5D instrument is now used in many health systems as a health outcomes measure. Recently an EQ-5D valuation study was conducted for Trinidad and Tobago, but thus far there have been no population norms published for Trinidad and Tobago or for any Caribbean country. The objective of this study is to provide a set of population norms, and to investigate inequalities in health in Trinidad and Tobago. The EQ-5D-5L questionnaire was included in the 2012/2013 Adult Population Survey of the Global Entrepreneurship Monitor for Trinidad and Tobago. This survey covered a representative sample of 2,036 adults aged 18 and over. Demographic data and self-reported health using EQ-5D-5L were collected. The Trinidad and Tobago value set was used to obtain EQ-5D index values. The Kakwani index and logistic regression models were used to evaluate inequalities in health. Mean EQ-5D index values and EQ-VAS values were calculated by age group, ethnicity, gender, income, educational attainment, employment status and place of residence. The 10 most commonly observed EQ-5D-5L states accounted for 90% of the respondents. The mean VAS value for the sample was 83.6 and the mean EQ-5D-5L index value was 0.95. Pain/discomfort was found to be the EQ-5D dimension with the highest prevalence of reported problems with 22% of the population reporting pain at any level. Self-care was the dimension with the lowest prevalence of problems reported at any level (3%). Health declines with increasing age, and men reported fewer problems and higher levels of self-reported health than women. Age, gender and education level were found to be important drivers of health status as measured by the EQ-5D instrument. Being in a very low income group was also observed to affect EQ-VAS values among younger respondents. The population norms provided in this study can be used by clinicians, academics and policy makers in several ways. They can be used in comparing different demographic groups or patient groups, or as a basis for tracking the progress of patients through a treatment regimen. They can also provide a baseline for cost utility analysis of health interventions for Trinidad and Tobago.

Background A five-level version of the EuroQol five-dimensional (EQ-5D) descriptive system (EQ-5D-5L) has been developed, but value sets based on preferences directly elicited from representative general population samples are not yet available. The objective of this study was to develop values sets for the EQ-5D-5L by means of a mapping ("crosswalk") approach to the currently available three-level version of the EQ-5D (EQ-5D-3L) values sets. Methods The EQ-5D-3L and EQ-5D-5L descriptive systems were coadministered to respondents with conditions of varying severity to ensure a broad range of levels of health across EQ-5D questionnaire dimensions. We explored four models to generate value sets for the EQ-5D-5L: linear regression, nonparametric statistics, ordered logistic regression, and item-response theory. Criteria for the preferred model included theoretical background, statistical fit, predictive power, and parsimony. Results A total of 3691 respondents were included. All models had similar fit statistics. Predictive power was slightly better for the nonparametric and ordered logistic regression models. In considering all criteria, the nonparametric model was selected as most suitable for generating values for the EQ-5D-5L. Conclusions The nonparametric model was preferred for its simplicity while performing similarly to the other models. Being independent of the value set that is used, it can be applied to transform any EQ-5D-3L value set into EQ-5D-5L index values. Strengths of this approach include compatibility with three-level value sets. A limitation of any crosswalk is that the range of index values is restricted to the range of the EQ-5D-3L value sets.

Diabet. Med. 28, 395–413 (2011) Abstract Background The EQ-5D is a generic preference-based health status measure that has been widely applied to measure the impact of Type 2 diabetes mellitus. This review summarizes evidence on the validity, reliability and responsiveness of the EQ-5D in studies of Type 2 diabetes and provides a catalogue of EQ-5D index scores for Type 2 diabetes and various complications and subgroups. Methods A structured search was conducted (1987–2009) using keywords relevant to Type 2 diabetes and the EQ-5D. Original research studies in Type 2 diabetes that reported EQ-5D results and/or measurement properties were included. Results Of the 59 included articles, 54 publications reported EQ-5D responses and 39 papers presented evidence on the measurement properties of the EQ-5D. Studies that reported measurement properties supported construct, convergent and discriminant validity, test–retest reliability and responsiveness of the EQ-5D in Type 2 diabetes. Several studies reported a ceiling effect for the EQ-5D and an inability to capture multiple complications was observed. EQ-5D index scores ranged from 0.20 (severe diabetic peripheral neuropathic pain) to 0.88 (general population: good HbA1c level). For six subgroups, sufficient studies were available to calculate pooled mean index scores (95% CI): general population 0.67 (0.59–0.75), no complications 0.76 (0.68–0.83), microvascular complications 0.73 (0.57–0.89), macrovascular complications 0.73 (0.57–0.88), diabetic peripheral neuropathic pain 0.45 (0.39–0.51) and retinopathy 0.57 (0.46–0.69). Conclusions Evidence supported validity, reliability and responsiveness of the EQ-5D in Type 2 diabetes. EQ-5D index scores associated with Type 2 diabetes and various complications can be useful for modelling health outcomes in economic evaluations of health programmes for Type 2 diabetes.

Objectives The aim of this study is a head-to-head comparison of the performance of the three-level EQ-5D (3L) and a newly developed five-level version (5L). Methods Eighty-two respondents valued 15 standardized disease descriptions and their own health on three response scales (3L, 5L, and visual analog scale [VAS]) for all five EQ-5D dimensions. Performance was studied in terms of feasibility, face validity, redistribution properties, ordinality, convergent validity, discriminatory power, and test–retest and interobserver reliability. Results The majority of participants judged 5L as the preferred system in terms of feasibility (76%) and face validity (75%). In total, 1.1% of responses were inconsistent. Ordinality of 5L was confirmed in all cases. Convergent validity of 3L-VAS (range: 0.88–0.99) and 5L-VAS (0.90–0.99) were high and about equal. Discriminatory power (informativity) improves considerably with 5L without loss of Evenness. Interobserver reliability (0.49 vs. 0.57) and test–retest reliability (0.52 vs. 0.69) were higher in 5L. Conclusion The EQ-5D five-level version appears a valid and reliable extension of the three-level system. The new 5L system is particularly useful for describing mild health problems and monitoring population health.

Background: Expansion of the EQ-5D health state classifier to 5 levels (EQ-5D-5L) has been proposed to improve discriminative and evaluative properties, but current preference-based algorithms were developed for a 3-level (EQ-5D-3L) structure. The objectives were to examine equivalency of meaning between 3L and 5L response systems, and to psychometrically derive a system of weights that facilitate conversion of 3L preference-based algorithms to a 5L system. Methods: Rasch models were used to examine the equivalency of the 3L and 5L systems using 2 datasets where health status was assessed using the 3L and 5L: a Dutch study of primarily hypothetical health state assessments and a US-based multicenter study of 423 cancer patients. Category-specific mean values of latent person parameters (using maximum likelihood estimation) for the levels of the 3L and 5L systems were estimated. Results: Means on the latent continuum pertaining to level 3 in the 5L system and level 2 in the 3L (some problems) were similar for both datasets, suggesting equivalence of these levels. Extremes of the 5L response structure consistently broadened the measurement continuum. By anchoring "no problems" as 0 dismility, disutility weights from EQ-5D-3L were transformed into weights for EQ-5D-5L using ratios of logit distances between person means for 5L and 3L calibrated for each dimension using the Rasch model. Conclusions: This study illustrates the rich potential for modem psychometric techniques both to examine equivalency when health status measures are modified as well as to inform preference-based measurement systems using existing value sets

© 2016 Published by Elsevier Inc. on behalf of International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Background Studies to produce value sets for preference-based measures of health require definition of a full health upper anchor if the values are to be used to calculate quality-adjusted life years. Recent value sets derived for the EQ-5D-5L instrument have described the upper anchor as "full health," whereas older valuation studies for the EQ-5D used "best health state" in the descriptive system (11111). It is unclear whether this change could have led to differences in the values obtained. The objective of this study was to assess differences in time trade-off (TTO) valuations using two different comparators (full health and 11111). Methods Preferences for EQ-5D-5L health states were elicited from a broadly representative sample of the UK general public. TTO data were collected by using computer-assisted personal interviews. Respondents were randomly allocated to one of two arms, each using a different comparator health state. Respondents completed 10 or 11 TTO valuations and a series of follow-up questions examining their interpretations of the term "full health." Results Interviews with 443 respondents were completed in 2014. The differences in mean values across arms are mostly small and nonsignificant. The two arms produced data of similar quality. There is evidence of interviewer effects. Health state 11111 was given a value of 1 by 98.2% of the respondents who valued it. Conclusions EQ-5D-5L values elicited by using the composite TTO approach are not greatly affected by the use of full health or 11111 as the comparator health state.

Aims To date, evidence to support the construct validity of the EQ-5D-5L has primarily focused on cross-sectional data. The aims of this study were to examine the responsiveness of EQ-5D-5L in patients with stroke and to compare it with responsiveness of EQ-5D-3L and visual analogue scale (EQ VAS). Methods We performed an observational longitudinal cohort study of patients with stroke. At 1 week and 4 months post-stroke, patients were assessed with modified Rankin Scale (mRS) and Barthel Index (BI) and were administered the EQ-5D-5L and EQ-5D-3L, including the EQ VAS. The EQ-5D-5L index scores were derived using the crosswalk methodology developed by the EuroQol Group. We classified patients according to two external criteria, based on mRS or BI, into 3 categories: ‘improvement,’ ‘stable’ or ‘deterioration’. We assessed the responsiveness of each measure in each patient subgroup using: effect size (ES), standardized response mean (SRM), F-statistic, relative efficiency and area under the receiver operating characteristic curve. Results A total of 112 patients (52 % females; mean age 70.6 years; 93 % ischemic stroke) completed all the instruments at both occasions. In subjects with clinical improvement, EQ-5D-5L was consistently responsive, showing moderate ES (0.51–0.71) and moderate to large SRM (0.69–0.86). In general, EQ-5D-3L index appeared to be more responsive (ES 0.63–0.82; SRM 0.77–1.06) and EQ VAS less responsive (ES 0.51–0.65; SRM 0.59–0.69) than EQ-5D-5L index. Conclusions The EQ-5D-5L index, based on the crosswalk value set, seems to be appropriately responsive in patients with stroke, 4 months after disease onset. As far as EQ-5D-5L index is scored according to crosswalk approach, the EQ-5D-3L index appears to be more responsive in stroke population.

__Introduction:__ Inconsistency in the time trade-off (TTO) task in EQ-5D-5L occurs when a respondent gives a higher value to a logically worse health state, the occurrence of inconsistency compromises the quality of the data. It is not yet clear which factors are associated with individual level inconsistency. Relating inconsistency to the characteristics of the respondent, interviewer, and the interview process could be helpful in understanding the causes of inconsistency. The objective of this paper is to discover the factors associated with individual level inconsistencies. __Methods:__ Twenty interviewers interviewed 1,296 respondents and each respondent valued 10 health states using the EQ-VT platform in 5 cities in China. At the respondent level, inconsistency was identified in terms of severity and quantity and related to the respondent’s background characteristics, the time and iterations spent on the wheelchair example task, and the formal TTO tasks, using multilevel multinomial regression analyses. Interviewers’ impact on inconsistencies was analyzed using single level multinomial regression analyses. __Results:__ In the full dataset, slight inconsistency was more related to the interview process (Time spent on TTO task: RRR = 1.246 with 95%CI: 1.076,1.441; time spent on Wheelchair example: RRR = 0.815 with 95%CI:0.699,0.952) while severe inconsistency was more related to respondent’s gender (Gender: RRR = 2.347 with 95%CI:1.429,3.855). One Interviewer (Interviewer 7: RRR = 7.335 with 95%CI:1.908,28.195) and interviewer’s experience (Sequence: RRR = 0.511 with 95%CI:0.385,0.678) in general showed strong influence over inconsistency in the TTO task. __Conclusion:__ In conclusion, logical inconsistency in the valuation of EQ-5D-5L health states is associated not only with respondents’ characteristics but also with interviewers’ performance and the interview process. The role of interviewers and the importance of interviewer training may be more crucial than hitherto believed. This finding could be generalizable to other interviewer-administered health-state valuation study.

OBJECTIVES: Our aim was to compare the quantitative position of the level descriptors of the standard EQ-5D three-level system (3L) and a newly developed, experimental five-level version (5L) using a direct and a vignette-based indirect method. METHODS: Eighty-two respondents took part in the study. The direct method represented a visual analog scale (VAS) rating of the nonextreme level descriptors for each dimension and each instrument separately. The indirect method required respondents to score 15 health scenarios with 3L, 5L and a VAS scale. Investigated were: (1) equidistance (Are 3L and 5L level descriptors distributed evenly over the VAS continuum?); (2) isoformity (Do the identical level descriptors on 3L and 5L yield similar results?); and (3) consistency between dimensions (Do the positions of similar level descriptors differ across dimensions within instruments?). RESULTS: Equidistance without transformation was rejected for all dimensions for both 3L and 5L but satisfied for 5L after transformation. Isoformity gave mixed results. Consistency between dimensions was satisfied for both instruments and both methods. DISCUSSION: The level descriptors have similar distributions across comparable dimensions within each system, but the pattern differs between 3L and 5L. This methodological study provides evidence of increased descriptive power and a broadened measurement continuum that encourages the further development of an official five-level EQ-5D

Objective: To estimate an interim five-level EuroQol five-dimensional (EQ-5D-5L) value set for Poland on the basis of the crosswalk methodology developed by the EuroQol Group. Methods: On the basis of data from 3691 respondents from six European countries, the EuroQol Group has developed a method of obtaining interim value sets for the EQ-5D-5L by means of mapping to the available three-level EuroQol five-dimensional (EQ-5D-3L) value sets (“crosswalk” methodology). A significant part of the data in this study came from Polish respondents (n ¼ 972; 26.3%). Poland is the first Central European country with EQ-5D-3L time trade-off–based social value set published. To obtain an interim EQ-5D-5L value set, we applied the crosswalk methodology to the Polish EQ-5D-3L value set. Results: Estimated Polish values for 3125 EQ-5D-5L health states are presented. Both EQ-5D-5L and EQ-5D-3L value sets have the same range (from � 0.523 to 1.000), but different means (0.448 vs. 0.380) and medians (0.483 vs. 0.403), respectively. Proportionately fewer states worse than dead were observed in the EQ-5D-5L (5.4%) value set than in the EQ5D-3L (13.2%) value set. Conclusions: The crosswalk-based value set is available for use in EQ-5D-5L studies in Poland to calculate health state utilities. It should be considered an interim value set until values based on preferences elicited directly from a sample representative of the Polish general population become available. This study helps users of the crosswalk algorithm understand the properties of the EQ-5D-5L values generated using this method, in comparison to EQ-5D-3L values obtained with the Polish time trade-off value set. It is likely that similar results would be observed for values sets in other countries because the same crosswalk methodology applies across all countries.

PURPOSE: The aim of this study was to assess the measurement properties of the 5-level classification system of the EQ-5D (5L), in comparison with the 3-level EQ-5D (3L). METHODS: Participants (n = 3,919) from six countries, including eight patient groups with chronic conditions (cardiovascular disease, respiratory disease, depression, diabetes, liver disease, personality disorders, arthritis, and stroke) and a student cohort, completed the 3L and 5L and, for most participants, also dimension-specific rating scales. The 3L and 5L were compared in terms of feasibility (missing values), redistribution properties, ceiling, discriminatory power, convergent validity, and known-groups validity. RESULTS: Missing values were on average 0.8 % for 5L and 1.3 % for 3L. In total, 2.9 % of responses were inconsistent between 5L and 3L. Redistribution from 3L to 5L using EQ dimension-specific rating scales as reference was validated for all 35 3L-5L-level combinations. For 5L, 683 unique health states were observed versus 124 for 3L. The ceiling was reduced from 20.2 % (3L) to 16.0 % (5L). Absolute discriminatory power (Shannon index) improved considerably with 5L (mean 1.87 for 5L versus 1.24 for 3L), and relative discriminatory power (Shannon Evenness index) improved slightly (mean 0.81 for 5L versus 0.78 for 3L). Convergent validity with WHO-5 was demonstrated and improved slightly with 5L. Known-groups validity was confirmed for both 5L and 3L. CONCLUSIONS: The EQ-5D-5L appears to be a valid extension of the 3-level system which improves upon the measurement properties, reducing the ceiling while improving discriminatory power and establishing convergent and known-groups validity.