Previous studies have summarized evidence on health-related quality of life for older people, identifying a range of measures that have been validated, but have not sought to present results by degree of frailty. Furthermore, previous studies did not typically use quality-of-life measures that generate an overall health utility score. Health utility scores are a necessary component of quality-adjusted life-year calculations used to estimate the cost-effectiveness of interventions.
We calculated normative estimates in mean and standard deviation for EQ-5D-5L, short-form 36-item health questionnaire in frailty (SF-36), and short-form 6-dimension (SF-6D) for a range of established frailty models. We compared response distributions across dimensions of the measures and investigated agreement using Bland-Altman and interclass correlation techniques.
The EQ-5D-5L, SF-36, and SF-6D scores decrease and their variability increases with advancing frailty. There is strong agreement between the EQ-5D-5L and SF-6D across the spectrum of frailty. Agreement is lower for people who are most frail, indicating that different components of the 2 instruments may have greater relevance for people with advancing frailty in later life. There is a greater risk of ceiling effects using the EQ-5D-5L rather than the SF-6D.
We recommend the SF-36/SF-6D as an appropriate measure of health-related quality of life for clinical trials if fit older people are the planned target. In trials of interventions involving older people with increasing frailty, we recommend that both the EQ-5D-5L and SF36/SF6D are included, and are used in sensitivity analyses as part of cost-effectiveness evaluation.