FAQS

Translation certificates for Paper Self-Complete versions are applicable for all corresponding modes of administration and can be provided upon request. Translation certificates only confirm and reflect the most extensive translation procedure and will not be revised whenever minor or major modifications are being made which in itself does not change the procedure.

EQ-5D is used by scientists across the world in different settings and for many different diseases. It is used by academia (e.g. universities, research institutes), governments (national, regional, municipal), industry (e.g. pharmaceuticals, medical devices) and by hospitals and clinics (e.g. hospitals, GP practices). At an international level, the pharmaceutical industry and scientific groups are the foremost users of the instrument. EQ-5D is frequently used in (multinational) clinical trials by pharmaceutical companies.

Several valuation techniques have been used to generate these value sets: time trade-off (TTO), visual analogue scale (VAS), and more recently, discrete choice experiments (DCE).

Please contact the EuroQol office.

The descriptive system section of the EQ-5D questionnaire produces a 5-digit health state profile that represents the level of reported problems on each of the five dimensions of health, e.g.EQ-5D-5L 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 one of the standard EQ-5D-5L value sets. These value sets reflect the preferences of the general population. In contrast, the EQ VAS scores are self-reported 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 (representing full health) and dead = 0 and can therefore be used in QALY calculations.

EQ-5D is the name of the instrument and is not an acronym. EQ-5D is the correct term to use in print or verbally.

The descriptive system section of the EQ-5D questionnaire produces a 5-digit health state profile that represents the level of reported problems on each of the five dimensions of health, e.g. EQ-5D-5L health state 11313 represents a patient who indicates moderate problems on the usual activities and anxiety/depression dimensions and no problems on the remaining dimensions. Please note that this is just a ‘shorthand’ way of describing an EQ-5D health state; the numbers are simply code for the level in each dimension and have no arithmetic properties whatsoever. Therefore, they should not, for example, be added to give an overall score.

A member of the EuroQol Office team will confirm safe receipt of the Translation Request and provide you with feasibility information, an estimated timeline and corresponding Approval Letter for signature within 10 business days. After confirmation of receipt of the signed Approval Letter, EuroQol will initiate the translation project. Default timelines EQ translation process: 10 business days from confirmation of receipt Translation Request to estimated project timeline from specialist translation agencies 10 business days from confirmation of receipt signed Approval Letter to project initiation 5 months on average to project completion

Note: these are our default response times. The overall timeline is also determined by the responsiveness of our clients and available linguistic resources for the requested language/country/mode of administration.

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

• Wille N, Badia X, Bonsel G, Burstrom K, Cavrini G, Devlin N, Egmar AC, Greiner W, Gusi N, Herdman M, Jelsma J. Development of the EQ-5D-Y: a child-friendly version of the EQ-5D. Qual Life Res 2010 Aug;19(6):875-886.
• Ravens-Sieberer U, Wille N, Badia X, Bonsel G, Burstrom K, Cavrini G, Devlin N, Egmar AC, Gusi N, Herdman M, J. Feasibility, reliability, and validity of the EQ-5D-Y: results from a multinational study. Qual Life Res 2010 Aug;19(6):887-897.

When publishing results obtained with the EQ-5D-5L, the following key 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.
• Rabin, R., & de Charro, F (2001). EQ-5D: a measure of health status from the EuroQol Group. Annals of Medicine 33(5):337-343.
• Herdman M, Gudex C, Lloyd A, Janssen MF, Kind P, Parkin D, Bonsel G, Badia X (2011). Development and preliminary testing of the new five-level version of EQ-5D (EQ-5D-5L). Quality of Life Research 20(10):1727-36.
• Janssen MF, Pickard AS, Golicki D, Gudex C, Niewada M, Scalone L, Swinburn P, Busschbach J (2013). Measurement properties of the EQ-5D-5L compared to the EQ-5D-3L across eight patient groups: a multi-country study. Quality of Life Research 22(7):1717-27.
• Buchholz I, Janssen MF, Kohlmann T, Feng YS (2018). A systematic review of studies comparing the measurement properties of the three-level and five-level versions of the EQ-5D. Pharmacoeconomics 36(6):645-661.
• Janssen MF, Bonsel GJ, Luo N (2018). Is EQ-5D-5L Better Than EQ-5D-3L? A Head-to-Head comparison of descriptive systems and value sets from seven countries/regions. Pharmacoeconomics 36(6):675-697.

Until recently, no value sets were available for EQ-5D-Y-3L because research showed that the approach used to value EQ-5D-3L health states for use in adult populations was not appropriate when valuing EQ-5D-Y-3L health states for use in economic evaluations of healthcare interventions for paediatric-age populations. Evidence has showed that health states are valued differently when used to describe an adult compared to a child, that valuation techniques suitable for valuing ‘adult’ health states may be unsuitable for valuing ‘youth’ health states, and that health state values are affected by the wording used in the instrument (the wording of EQ-5D-Y-3L health states differs somewhat from that of EQ-5D-3L health states). Consequently, EQ-5D-3L value sets should not be used to assign values to EQ-5D-Y-3L health states.

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. The rationale behind this is that the values are supposed to reflect the preferences of local taxpayers and potential receivers of healthcare. The EQ-5D value sets are therefore based on the values of the general population.

If you need to obtain health state utility values for the EQ-5D-5L, the recommendation is to use the United States EQ-5D-5L value set from Pickard et al. (2019) as the United Kingdom valuation study is currently ongoing. If you need to obtain health state utility values for the EQ-5D-3L, it is recommended to use the United Kingdom value set from Dolan et al. (2002).

A standardized valuation study protocol (called EQ-VT) was developed by the EuroQol Group to create standard value sets for the EQ-5D-5L. This protocol is based on the use of the composite time trade-off (cTTO) valuation technique, supplemented by a discrete choice experiment (DCE). We recommend EQ-5D-5L users to use the standard value sets, as these were produced with the EuroQol Group’s standardised valuation technology EQ-VT.

Several valuation techniques have been used to generate these value sets: time trade-off (TTO), visual analogue scale (VAS), and more recently, discrete choice experiments (DCE).

The time trade-off (TTO), visual analogue scale (VAS) and discrete choice experiment (DCE) 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 certain suboptimal health state for 10 years and then to specify the amount of time they would be willing to give up to live in full health instead. For example, someone might consider that 8 years in full health is equivalent to 10 years in the suboptimal health state.

The VAS technique 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.

The DCE asks people to choose between two (or more) health states of varying severity across the five EQ-5D health domains (e.g. which is better, state A [32233] or state B [32321]?).

There has been much discussion about the theoretical and empirical properties of these three methods, and whether it is justified to calculate QALYs using values based on these methods, although all three techniques have been used to calculate QALYs. Currently, EQ-5D-5L value sets which are developed using the EQ-VT platform are based either on a combination of TTO and DCE values, or on TTO values only.

Please note that this is a large subject area and the brief answer provided above includes minimal details.  For further information, the reader is encouraged to review the literature.

The responses to the five EQ-5D dimensions (i.e. an EQ-5D health state or profile) can be converted into a single number called an index value. The index value reflects how good or bad the health state is according to the preferences of the general population of a country/region. The collection of index values for all possible EQ-5D states is called a value set.

Please see this webpage on choosing a value set. Many factors determine if another country’s value set can be used, such as geography, religion, language, level of development of the country, healthcare system etc. In addition, local HTA guidelines may come into play. Therefore, it is advised to contact local regulatory authorities about their requirements.

Please note, if a standard EQ-5D-5L value set is not available for your country, then an interim “crosswalk” value set can be used, if available. A crosswalk value set is one that has been created for the EQ-5D-3L and then adapted to fit the EQ-5D-5L descriptive system. More information on the crosswalk can be found here.

Data on EQ-5D health states gathered in the context of a multinational trial may be converted into a single summary index using one of the available EQ-5D-3L value sets. 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 EQ-5D-3L health states in that specific 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 information about 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 to 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 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-3L valuation protocols, guidelines for choice of value set and tables of all available value sets have 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.

Please contact our scientific director.

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. The rationale behind this is that the values are supposed to reflect the preferences of local taxpayers and potential receivers of healthcare. The EQ-5D value sets are therefore based on the values of the general population.