How to use EQ-5D
The EQ-5D-3L essentially consists of 2 pages - the EQ-5D descriptive system (page 2) and the EQ visual analogue scale (EQ VAS) (page 3). The EQ-5D-3L descriptive system comprises the following 5 dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each dimension has 3 levels: no problems, some problems, extreme problems.
Scoring the EQ-5D-3L Descriptive System
The respondent is asked to indicate his/her health state by ticking (or placing a cross) in the box against the most appropriate statement in each of the 5 dimensions.
Scoring the EQ VAS
The EQ VAS records the respondent’s self-rated health on a vertical, visual analogue scale where the endpoints are labelled ‘Best imaginable health state’ and ‘Worst imaginable health state’. This information can be used as a quantitative measure of health outcome as judged by the individual respondents.
In 2005, a Task Force was established within the EuroQol Group to investigate methods to improve the instrument’s sensitivity and to reduce ceiling effects. After much discussion, the Task Force decided that there should be no change in the number of dimensions for a new version of EQ-5D. However, previously published studies by EuroQol Group members showed that experimental 5-level versions of EQ-5D could significantly increase reliability and sensitivity (discriminatory power) while maintaining feasibility and potentially reducing ceiling effects. The Group therefore decided that the new version of the EQ-5D should include five levels of severity in each of the existing five EQ-5D dimensions and that it would be called the EQ-5D-5L (Figure 1) . The existing EQ-5D will be renamed the EQ-5D-3L.
The EQ-5D-5L still consists of 2 pages – the EQ-5D-5L descriptive system (page 2) and the EQ visual Analogue scale (EQ VAS) (page 3). The descriptive system comprises the same 5 dimensions as the EQ-5D-5D-3L (mobility, self care, usual activities, pain/discomfort, anxiety/depression). However, each dimension now has 5 levels: no problems, slight problems, moderate problems, severe problems, and extreme problems.
Scoring the EQ-5D-5L Descriptive System
The respondent is asked to indicate his/her health state by ticking (or placing a cross) in the box against the most appropriate statement in each of the 5 dimensions. This decision results in a 1-digit number expressing the level selected for that dimension. The digits for 5 dimensions can be combined in a 5-digit number describing the respondent’s health state.
It should be noted that the numerals 1-5 have no arithmetic properties and should not be used as a cardinal score. During the development of the EQ-5D-5L, the opportunity was also taken to improve some of the wording in the dimensions to enhance consistency and facilitate understanding. For example, the old wording of ‘confined to bed’ to indicate the upper extreme in the EQ-5D-3L has been replaced with ‘I am unable to walk about’ which is more consistent with the wording within the Mobility dimension and with the extreme levels on other dimensions.
Scoring the EQ VAS
The EQ VAS records the respondent’s self-rated health on a 20 cm vertical, visual analogue scale with endpoints labelled ‘the best health you can imagine’ and ‘the worst health you can imagine’. This information can be used as a quantitative measure of health as judged by the individual respondents.
The instructions for the EQ VAS task have been changed and simplified in the EQ-5D-5L. The EuroQol Group had received feedback over the years that respondents sometimes found it difficult to draw a line from the box to the scale. It was also cumbersome for administrators to record their scores. The EQ-5D-5L now asks respondents to simply ‘mark an X on the scale to indicate how your health is TODAY’ and then to ‘write the number you marked on the scale in the box below’. This should make the task easier for both respondents and users.