EQ-5D-5L

General

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Is the EQ-5D-5L instrument validated?


The EQ-5D-5L has recently been validated in a diverse patient population in 6 countries, including 8 patient groups with chronic conditions (cardiovascular disease, respiratory disease, depression, diabetes, liver disease, personality disorders, arthritis, stroke) and a student cohort. Redistribution of responses from the EQ-5D-3L to EQ-5D-5L was validated for all dimensions and all levels. The measurement properties of EQ-5D-5L were superior to the EQ-5D-3L in terms of feasibility, ceiling effects, discriminatory power and convergent validity.

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For what period of time does EQ-5D-5L record health status?


Self-reported health status captured by EQ-5D-5L relates to the respondent’s situation at the time of completion. No attempt is made to summarise recalled health status over the preceding days or weeks, although EQ-5D-3L has been tested in recall mode. An early decision taken by the EuroQol Group determined that health status measurement ought to apply to the respondent’s immediate situation - hence the focus on ‘your health today’.

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Can the EQ-5D-5L now be used instead of the EQ-5D-3L?


Yes, the EQ-5D-5L can be used instead of the EQ-5D-3L but please bear in mind that currently there are no value sets available that are directly elicited from representative general population samples.

For the purpose of comparing EQ-5D results with previous research based on the EQ-5D-3L, or when used in longitudinal research based on the EQ-5D-3L, it is advised to use the EQ-5D-3L, or both the EQ-5D-3L and EQ-5D-5L.

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The new EQ-5D-5L lacks country-specific value sets for index calculations. Despite this, should we use this new instrument or should we use the EQ-5D-3L until value sets become available?


It is true that currently there are no directly elicited value sets available for the EQ-5D-5L although valuation studies are planned for 2012 in Canada, UK, Spain and the Netherlands. In the meantime, a response mapping approach has been developed that estimates the relationship between responses to the EQ-5D-3L (‘3L’) and EQ-5D-5L (‘5L’) Descriptive systems, and subsequently establishes a link (or crosswalk) to the 3L value sets.

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Can I use only the EQ-5D-5L descriptive system or only the EQ VAS?


We cannot advise this. EQ-5D-5L is a 2-part instrument so if you only use one part you cannot claim to have used EQ-5D-5L in your publications.

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How long should the EQ VAS be?


Officially, for paper versions, the EQ VAS scale should be 20cms. All methodological and developmental work has been carried using this length. To ensure that you print the correct length, make sure your paper size is set at A4 and the box in your printing instructions labelled ‘scale to paper size’ is set at ‘no scaling’.

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Can I publish our study using EQ-5D?


Yes, you are free to publish your results. If you are reproducing the EQ-5D-5L in an appendix we request that you use the sample version of EQ-5D-5L and that the following text is included in the footer: 1990 EuroQol Group. EQ-5D™ is a trade mark of the EuroQol Group

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How do I refer to the EQ-5D-5L instrument in publications?


When publishing results obtained with the EQ-5D-5L, the following references can be used:

  1. The EuroQol Group (1990). EuroQol-a new facility for the measurement of health-related quality of life. Health Policy 16(3):199-208.
  2. Brooks R (1996). EuroQol: the current state of play. Health Policy 37(1):53-72.
  3. Herdman M, Gudex C, Lloyd A, Janssen MF, Kind P, Parkin D, Bonsel G, Badia X. Development and preliminary testing of the new five-level version of EQ-5D (EQ-5D-5L). Quality of Life Research (accepted for publication).
  4. Janssen MF, Pickard AS, Golicki D, Gudex C, Niewada M, Scalone L, Swinburn P, Busschbach J. Measurement properties of the EQ-5D-5L compared to the EQ-5D-3L across eight patient groups: a multi-country study
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What is the difference between the EQ-5D-5L descriptive system and the EQ VAS?


The descriptive system can be represented as a health state, e.g. health state 21143 represents a patient who indicates slight problems on the mobility dimension, no problems on the self-care and usual activities dimensions, severe pain or discomfort, and moderate problems on the anxiety/depression dimension. These health states can be converted to a single index value using the crosswalk link function based on the existing value sets for the EQ-5D-3L described in Section 4 above. These EQ-5D-3L value sets are based on VAS or TTO valuation techniques, and reflect the opinion of the general population. The EQ VAS scores are patient-based and are therefore not representative of the general population. The EQ VAS self-rating records the respondent’s own assessment of their health status. The EQ VAS scores however are anchored on 100 = the best health you can imagine and 0 = the worst health you can imagine, whereas the value sets are anchored on 11111 = 1 and dead = 0 and can therefore be used in QALY calculations.

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What is the difference between the VAS and TTO techniques?


The difference between the TTO- and VAS-based value sets is that the techniques used to elicit the values on which the models are based differ. In the TTO task, respondents are asked to imagine that they will live in a certain health state (e.g. 33333) for 10 years and have to specify the amount of time they would be willing to give up to live in full health instead (i.e. 11111). For example, someone might find 8 years in 11111 equivalent to 10 years in 33333. The VAS technique on the other hand, asks people to indicate where, on a vertical thermometer-like scale ranging from best imaginable health to worst imaginable health, they think a health state should be positioned.

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General population value sets vs. patient population value sets


If you want to undertake a utility analysis you will need to use a value set. Generally speaking, utility analysis requires a general population-based value set (as opposed to a patient-based set). The rationale behind this is that the values should reflect the preferences of local taxpayers and potential receivers of healthcare. Additionally, patients tend to rate their health states higher than the general population because of coping or other factors, and may therefore underestimate their need for healthcare. EQ-5D-5L value sets are therefore based on general population values.

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Multinational clinical trials


Information relating to EQ-5D-5L health states gathered in the context of multinational trials may be converted into a single index value using the crosswalk link function based on the available EQ-5D-3L value sets as described in Section 4 above. There are different options available to do this using appropriate value sets-however the choice depends on the context in which the information will be used by researchers or decision makers. In cases where data from an international trial are to be used to inform decision makers in a specific country, it seems reasonable to expect decision makers to be interested primarily in value sets that reflect the values for health states in that country. So for example, if applications for reimbursement of a drug are rolled out from country to country, country-specific value sets should be applied and reported in each pharmaco-economic report. This is no different from the requirement to use country specific costs. In the absence of a country-specific value set, the researcher should select another set of values for a population that most closely approximates that country. Sometimes however, information about index values ('utilities') is required to inform researchers or decision makers in an international context. In these instances, one value set applied over all health states data is probably more appropriate. The decision about which value set to use will also depend on whether the relevant decision making body in each country specifies any requirements or preferences in regard to the methodology used in different contexts (e.g. TTO, standard gamble (SG), VAS or discrete choice modelling (DCM)). These guidelines are the topic of an on-going, international debate but the EuroQol Group website is planning to provide a summary of health care decision-making bodies internationally together with their stated requirements regarding the valuation of health states. Detailed information on valuation protocols together with guidelines on which value set to use and tables of all available value sets has recently been published by Springer in: EuroQol Group Monograph series: Volume 2: EQ-5D value sets: inventory, comparative review and user guide’ (see section 8 for more information). Chapter 4 by Nancy Devlin and David Parkin will be of special interest to researchers pondering the issue of which value set to use.

Registration

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How can I obtain the EQ-5D-5L instrument?


If you have already seen the EQ-5D-5L and/or decided to go ahead and use it, please register your study/project/trial first, by completing the EQ-5D registration form. The EuroQol Executive Office will then contact you by e-mail and inform you about the terms and conditions which apply to your use of the EQ-5D-5L, including licensing fees (if applicable). Please allow 3 working days to receive this reply.

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I am not conducting a study but would like to use the EQ-5D to measure clinical outomes. Do I still need to register?


Yes. You can only obtain EQ-5D versions by completing the EQ-5D Registration Form.

Licensing

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Do I have to pay for using the EQ-5D-5L questionnaire?


Licensing fees are determined by the EuroQol Executive Office on the basis of the user information provided on the registration form. The amount is dependent upon the type of study, funding source, sample size and number of requested languages. You are not obligated to purchase by registering.

Copyright

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Is the EQ-5D-5L a copyrighted instrument?


Yes. Please note that without the prior written consent of the EuroQol Executive Office, you are not permitted to i.e. use, reproduce, alter, amend, convert, translate, publish or make available in whatever way (digital, hard-copy etc.) the EQ-5D-5L and related proprietary materials.

The EuroQol Group stresses that any and all copyrights in the EQ-5D, its (digital) representations, and its translations exclusively vest in the EuroQol Group. EQ-5D™ is a trade mark of the EuroQol Group.