Measurement properties of the EQ-HWB-9 among older adults in five english-speaking countries

This study investigated the performance of the 9-item EQ Health and Wellbeing instrument (EQ-HWB-9) in measuring health-related quality of life (HRQL) and broader aspects of health among older adults across five English-speaking countries. Data from the EuroQol Data for Assessment of Population Health Needs and Instrument Evaluation (EQ-DAPHNIE) project in Canada, United States of America (USA), United Kingdom (UK), Australia, and New Zealand were analyzed. Descriptive analyses were conducted by country; distributional properties of the measure including floor/ceiling effects were examined; instrument performance was evaluated by assessing convergent and discriminative validity. The UK experimental value set was used to calculate an EQ-HWB-9 index score for all countries. The performance of the EQ-HWB-9 was also compared with that of the EQ-5D-5L in these populations. A total of 5,274 respondents aged 65 years or older (Canada, n = 1278; USA, n = 1042; UK, n = 953; Australia, n = 1204; and New Zealand, n = 797) were included. The mean EQ-HWB-9 index scores ranged from 0.81 (SD 0.19) in Canada to 0.85 (SD 0.18) in New Zealand. No substantial floor effects were observed, and only the UK showed a near-threshold ceiling effect. Spearman correlations indicated that the EQ-HWB-9 supported expected patterns of convergent validity. Known-group comparisons showed that EQ-HWB-9 effectively distinguished between individuals based on having a chronic condition across 15 conditions, as well as between groups defined by different health states according to other measures. The EQ-HWB-9 performed well in capturing different aspects of HRQL among older adults across five countries, and can provide added value in assessing psychosocial aspects of health.