A Quantitative Exploration of the Performance of a Potential “Health and Well-Being” Visual Analog Scale (EQ-HWB VAS) for the EQ-HWB-9

OBJECTIVES: All EuroQol instruments include a visual analog scale (VAS), except the EuroQol Health and Well-Being (EQ-HWB), which captures broader aspects of well-being beyond health, relevant to populations providing and receiving care. This study explored the performance of a potential VAS for EQ-HWB. METHODS: The EQ-HWB VAS was developed by adapting the EQ VAS from the EuroQol 5-Dimension 5-Level instrument (EQ-5D-5L), replacing "health" with "health and well-being" and "today" with "last week" to align the recall period with EQ-HWB. A cross-sectional survey was undertaken with an age- and sex-representative sample of the Hong Kong general population (n = 1262). Descriptive characteristics, ceiling and floor, convergent and known-group validity, and explanatory power were assessed. The performance of the EQ-HWB VAS was directly compared with the EQ VAS. RESULTS: The mean EQ VAS and EQ-HWB VAS scores were 76.7 and 73.5 (P < .001). The ceiling was 5.2% for the EQ VAS and 3.6% for EQ-HWB VAS. The EQ-HWB VAS showed a very strong correlation and agreement with EQ VAS. Both the EQ VAS and EQ-HWB VAS were able to distinguish between most known groups. The EQ-HWB VAS showed larger effect sizes for groups such as caregiving, perceived income level and mental health problems. EQ-HWB-9 items explained more variance in EQ-HWB VAS scores than EQ-5D-5L dimensions did in EQ VAS scores. CONCLUSIONS: This study provides the first evidence of the measurement properties of a "health and wellbeing" VAS for EQ-HWB, demonstrating its validity. Further research is recommended in different languages and countries to inform decisions about the addition of a VAS to the EQ-HWB.