Understanding the different EQ-5D-5L versions by age
Developed by the EuroQol Group, the EQ-5D is a widely-used health questionnaire that assesses an individual's health-related quality of life (HRQoL) across five dimensions. To ensure the instrument is relevant and comprehensible for different populations, the developers created several age-specific versions. The standard EQ-5D-5L, with its five severity levels, is primarily for adults, while a dedicated version, the EQ-5D-Y-5L, is designed for younger populations. Researchers and clinicians must select the appropriate version to obtain reliable data.
The adult version: EQ-5D-5L
The standard EQ-5D-5L is intended for use with adult populations. Most studies consider the starting age for the adult version to be 18 years or older, though some national norms may vary slightly, such as studies covering individuals 15 years and older. The descriptive system covers five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression, each with five levels of severity. The adult version has been extensively validated and provides robust data for economic evaluations and clinical research in adults. While the instrument is psychometrically sound for the general adult population, some studies have noted that older adults may have a higher rate of incomplete responses or require more assistance.
The youth version: EQ-5D-Y-5L
To address the limitations of using an adult-focused tool with younger populations, the EuroQol Group developed the EQ-5D-Y (youth) instrument. The five-level version, EQ-5D-Y-5L, is designed for self-completion by children and adolescents between the ages of 8 and 15 years. This version modifies the wording of the dimensions to be more child-friendly, for example, using "walking about" instead of "mobility". This adaptation ensures better comprehension and more accurate responses from younger individuals.
Age considerations for the youth version:
- 8 to 15 years: Self-completion of the EQ-5D-Y-5L is recommended.
- 4 to 7 years: Proxy versions, completed by a parent, caregiver, or interviewer, are available for this age group.
Bridging the gap: Adolescents aged 16 and 17
For adolescents aged 16 and 17, the choice between the youth (EQ-5D-Y-5L) and adult (EQ-5D-5L) versions can depend on the specific research context. In some studies, a comparison of the adult and youth versions showed insufficient agreement in older adolescent populations (mean age 14, range 12–18). However, the adult version is generally recommended for those 16 and older. In longitudinal studies that span from adolescence into adulthood, using a single instrument consistently is often preferred to avoid data discontinuities.
Challenges and feasibility in different age groups
While the EQ-5D-5L is a feasible instrument across a wide age range, certain factors influence its applicability. In older adults, cognitive changes or physical limitations can lead to higher rates of missing data, particularly for the visual analogue scale (EQ VAS). In these cases, interviewer-administered methods are often used to ensure higher completion rates. For very young children, proxy completion by a caregiver is necessary, but this introduces the possibility of proxy bias, where the caregiver's perception may differ from the child's true experience.
Comparison of EQ-5D versions and age suitability
| Instrument Version | Age Range | Administration | Specific Considerations |
|---|---|---|---|
| EQ-5D-Y-5L (Proxy) | 4–7 years | Interviewer or Proxy | Language is child-friendly; relies on caregiver assessment |
| EQ-5D-Y-5L (Self-Report) | 8–15 years | Self-Completion | Features child-friendly wording for better comprehension |
| EQ-5D-5L (Adult) | 16+ years | Self-Completion | Standard version for adolescents and adults |
| EQ-5D-5L (Elderly) | 65+ years | Self-Completion or Interviewer | Higher rate of incomplete responses may occur; interviewer support can help |
Conclusion
The age range for the EQ-5D 5L is not universal but is dependent on the specific version of the instrument used. The EuroQol Group provides validated versions tailored for adults (EQ-5D-5L for ages 16 and older) and youth (EQ-5D-Y-5L for ages 8–15). For children too young to self-report (ages 4–7), proxy versions are available. The development of these age-specific tools highlights the importance of using appropriate measures to accurately capture health-related quality of life across the lifespan. By using the correct version, researchers and clinicians can ensure the data collected is relevant, reliable, and reflects the unique health perspectives of different age groups.
