EQ-5D

The EQ-5D questionnaire is a widely used generic measure of health-related quality of life, frequently employed in clinical trials and prospective studies. It consists of 5 questions, each addressing a different domain: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. There are typically 3 response levels per domain (EQ-5D-3L; NICE’s preferred tool), but a 5-level version (EQ-5D-5L) is now also available. The EQ-5D instument is quick and easy to use, has been extensively researched/validated, and has been translated into many different languages. A key strength of the EQ-5D is its generic nature, allowing for comparisons across diverse disease areas, though its applicability can be limited in specific conditions like severe mental health issues or highly specialised disabilities (e.g. blindness). The importance of the EQ-5D lies in its ability to generate utility scores for each health state, derived from population surveys. These scores can be combined with appropriate durations to generate quality-adjusted life years, which can be used in cost-utility analyses. During clinical trials, it is generally recommended that the EQ-5D is administered alongside a disease-specific quality-of-life instrument that is more sensitive to specific aspects of the condition and the potential impact of the therapy. NICE guidelines state that the EQ-5D is the preferred measure of HRQoL in adults, and “when EQ-5D data are not available or are inappropriate for the condition or effects of treatment, the valuation methods should be fully described and comparable to those used for the EQ-5D”.