EQ-5D-5L | FAQs
Is the EQ-5D-5L instrument validated?
The EQ-5D-5L has recently been validated in a diverse patient population in six countries. It was tested in 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.
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 summarize the 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’.
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. However, please bear in mind that only some countries have EQ-5D-5L value sets that are directly elicited from representative general population samples.
If you wish to compare EQ-5D results with previous research based on EQ-5D-3L, or to undertake longitudinal research based on EQ-5D-3L, it is advisable to use the EQ-5D-3L, or both the EQ-5D-3L and the EQ-5D-5L.
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 correct that only some countries directly elicited value sets for the EQ-5D-5L, although further valuation studies are planned. In the meantime, a response mapping approach has been developed that estimates the relationship between responses to the EQ-5D-3L and EQ-5D-5L descriptive systems, and subsequently establishes a link (or crosswalk) from EQ-5D-3L to EQ-5D-5L value sets.
Can I use only the EQ-5D-5L descriptive system or only the EQ VAS?
We cannot advise this. EQ-5D-5L is a two-part instrument. If you only use one part, you cannot claim to have used EQ-5D-5L in your publications.
How long should the EQ VAS be?
For paper versions, the EQ VAS scale should be 20 cm. All methodological and developmental work has been carried on VAS of this length. To ensure that you print the correct length, set your paper size is at A4 and make sure that the box in your printing instructions labelled ‘scale to paper size’ is set at ‘no scaling’.
Can I publish our study using EQ-5D?
Yes, you are free to publish your results. If you are reproducing the EQ-5D-5L, we request that you use the sample version of EQ-5D-5L. Also, please include the copyright statement located in the footer of each EQ-5D-5L language version.
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:
- The EuroQol Group (1990). EuroQol-a new facility for the measurement of health-related quality of life. Health Policy 16(3):199-208.
- Brooks R (1996). EuroQol: the current state of play. Health Policy 37(1):53-72.
- 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.
- 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
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 into 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. In contrast, 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. Furthermore, the EQ VAS scores 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.
What is the difference between the TTO and VAS techniques?
The TTO and VAS value sets differ in the technique used to elicit the values for the models. In the TTO task, respondents are asked to imagine they live in a health state (e.g. 33333) for 10 years and then 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 consider that 8 years in 11111 is equivalent to 10 years in 33333. The VAS technique, on the other hand, asks people to indicate where they think a health state should be positioned on a vertical thermometer-like scale ranging from best imaginable health to worst imaginable health.
General population value sets vs. patient population value sets
To undertake a utility analysis you will need to use a value set. Generally speaking, utility analysis requires a value set based on preferences from a general population (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 health states higher than the general population do because of coping strategies etc., thus underestimating the need for healthcare. EQ-5D-5L value sets are therefore based on general population values.
Multinational clinical trials
Data on EQ-5D-5L health states of a multinational trial 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 researchers or decision makers will use the information. In cases where data from a multinational 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. For example, if applications for reimbursement of a drug are rolled out from country to country, then 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, it is probably more appropriate to apply one value set over all the EQ-5D health state data. The decision about which value set to use will 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 international ongoing debate, but the EuroQol Group website is planning to provide a summary of health care decision-making bodies internationally, including their stated requirements regarding the valuation of health states. Detailed information regarding the EQ-5D valuation protocols, guidelines for choice of value set and tables of all available value sets have 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.
How can I obtain the EQ-5D-5L instrument?
If you have already seen the EQ-5D-5L and/or have decided to go ahead and use it, please register your study/project/trial first, by completing the EQ-5D registration form. The EuroQol 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.
I am not conducting a study but would like to use the EQ-5D to measure clinical outcomes. Do I still need to register?
Yes. You can only obtain EQ-5D versions by completing the EQ-5D Registration Form.
Do I have to pay for using the EQ-5D-5L instrument?
Licensing fees are determined by the EuroQol Office on the basis of the user information provided in the registration form. The size of the payment depends on the type of study, funding source, sample size and number of requested languages. You are not obligated to purchase by registering.
Is the EQ-5D-5L a copyrighted instrument?
Yes. Please note that without the prior written consent of the EuroQol Office, you are not permitted to 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 Research Foundation stresses that any and all copyrights in the EQ-5D, its (digital) representations, and its translations are exclusively vested in the EuroQol Research Foundation. EQ-5D™ is a trade mark of the EuroQol Research Foundation.