The EQ-5D is one of the most widely used generic measures of health-related quality of life. This page explains what the EQ-5D is, what it measures, the questions it contains, how it is scored, and how it is used in clinical and economic evaluation.
What is the EQ-5D?
The EQ-5D is a standardized, generic instrument for describing and valuing health-related quality of life, developed by the EuroQol Group. Because it is generic rather than condition-specific, it can be used across a wide range of conditions and treatments and is frequently used in clinical studies, population health surveys, and health-economic analyses. The most common current version, the EQ-5D-5L, was introduced in 2009 to improve sensitivity and reduce ceiling effects compared with the earlier three-level EQ-5D-3L.
What does the EQ-5D measure?
The EQ-5D has two parts: a descriptive system and a visual analog scale. The descriptive system measures health across five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. The EQ VAS records the respondent's self-rated overall health on the day of completion.
What questions are included in the EQ-5D?
The descriptive system contains one question for each of the five dimensions. In the EQ-5D-5L, each dimension has five response levels: no problems, slight problems, moderate problems, severe problems, and extreme problems. The respondent selects the level that best describes their health that day for each dimension. The EQ VAS is a vertical scale on which the respondent marks their overall health from 0 (the worst health you can imagine) to 100 (the best health you can imagine).
How is the EQ-5D scored?
The five selected levels combine into a five-digit health-state code (for example, 11111 represents no problems on any dimension). This health state is converted into a single summary index value using a country-specific value set derived from general-population preference studies. An index value of 1 represents full health and 0 represents a state equivalent to death, with negative values possible for states considered worse than death. The EQ VAS is reported separately on its 0-to-100 scale. Because index values depend on the value set used, the country and version should always be reported.
How is the EQ-5D used in clinical practice?
The EQ-5D is used to track overall health-related quality of life before and after treatment, to compare burden across conditions, and to generate quality-adjusted life years (QALYs) for cost-effectiveness analysis. In orthopedics and many other specialties it is often collected alongside a condition-specific PROM so that both general and joint-specific or disease-specific change can be captured.
Strengths and limitations
The EQ-5D is short, generic, and internationally validated, and it supports economic evaluation through index values. Its limitations include being less sensitive to small, condition-specific changes than targeted measures, and dependence on the chosen country value set, which affects comparability. It is typically paired with a condition-specific instrument for a complete picture.
Frequently asked questions
What is the difference between EQ-5D-3L and EQ-5D-5L? The 3L version has three response levels per dimension and the 5L version has five, which improves sensitivity and reduces ceiling effects.
What does an EQ-5D index of 1 mean? An index of 1 represents full health; 0 represents a state equivalent to death, and negative values represent states rated worse than death.
Is the EQ VAS the same as the index value? No. The EQ VAS is the patient's self-rated overall health from 0 to 100, while the index value is derived from the five-dimension health state using a value set.
References
- EuroQol Group. EuroQol - a new facility for the measurement of health-related quality of life. Health Policy. 1990;16(3):199-208.
- Herdman M, Gudex C, Lloyd A, et al. Development and preliminary testing of the new five-level version of EQ-5D (EQ-5D-5L). Quality of Life Research. 2011;20(10):1727-1736.
- EuroQol Research Foundation. EQ-5D-5L User Guide. Available at: euroqol.org.
