EQ-5D-5L in multiple sclerosis: Estimated utility values, minimal (clinically) important changes, and direct and indirect influences over time

In multiple sclerosis (MS), studies reporting mean EQ-5D-5L health utility values ranged from 0.31-0.82 and a 2024 systematic review found no published anchor-based estimates for EQ-5D-5L Minimal Important Change (MIC). We derived age-sex specific utility reference values and MIC of the EQ-5D-5L in a large UK sample with MS. The Trajectories of Outcomes in Neurological Conditions-MS study calculated EQ-5D-5L age-sex and disability-subtype specific utility estimates. Multiple regression identified possible predictors of health status for inclusion into a Structural Equation Model (SEM). Calculation of MIC used an anchor-based method. Among 5509 participants, female (73.7%), aged 17-87, mean EQ-5D-5L utility was 0.682 (95% CI: 0.675-0.688; range -0.28-1.0). There was an age gradient and difference between male and female utilities across each age group (age: F 34.3 (df 11, 497): p<0.001; sex: t 5.794; (df 5507): p<0.001). In SEM, higher self-efficacy improved EQ-5D-5L while cognitive problems, progressive disease, fatigue, bladder problems and stigma decreased EQ-5D-5L. In the longitudinal sample comprising 2066 pwMS, mean utility value at follow-up was 0.673 (95% CI: 0.662-0.683), MIC 0.146 (95% CI: 0.137-0.154). MIC varied significantly by MS subtype and for those reporting a relapse within the past year. Health utility values for MS are consistently lower than those found in the English population, and are influenced by factors amenable to clinical intervention. Anchor-based MIC varied by subtype and relapse history, showing that when assessing the significance of changing health status from the perspective of those with MS, a uniform MIC should not be employed.