Assessing the relative importance of key quality of life dimensions for people with and without a disability: an empirical ranking comparison study

BACKGROUND: In economic evaluation, the quality of life of people with a disability has traditionally been assessed using preference-based instruments designed to measure and value quality of life. To provide robust measurement of the effectiveness of programs designed to improve the quality of life of people living with a disability, preference-based measures need to be sufficiently sensitive to detect incremental changes in the quality of life dimensions that are most important to people who have a disability. This study sought to explore whether there was a difference in the ranked order of importance of quality of life dimensions between people with a disability and people without a disability. METHODS: An online survey was developed and administered Australia wide. The first sample (n = 410) comprised adults (aged ≥ 18 years) with a disability (n = 208) and family carers of person/s with a disability who were asked to respond on behalf of the person with a disability (n = 202). The second sample included adults without disability (n = 443). Respondents were asked to rank the importance of 12 quality of life dimensions extracted from the content of established preference-based quality of life measures (EQ-5D, AQoL and ASCOT). RESULTS: People with a disability placed relatively higher importance on broader quality of life dimensions (e.g. Control, Independence, Self-care) relative to health status focused dimensions (e.g. Vision, Hearing, Physical mobility). This distinction was less differentiable for those ‘without a disability’. The biggest differences in ranked importance of dimensions were in: Vision (‘with disability’ = 10th, ‘without disability’ = 4th), Self-care (‘with disability’ = 3rd, ‘without disability’ = 7th) and Mental well-being (‘with disability’ = 6th, ‘without disability’ = 2nd). CONCLUSIONS: The relative importance of quality of life dimensions for people with a disability differs to people without a disability. Quality of life is a key outcome for economic evaluation and for assessing the impact of disability care policy and practice in Australia and internationally. It is important that the effectiveness of interventions is measured and valued in ways which are fully reflective of the quality of life preferences of people with a disability.