OBJECTIVES: For healthcare treatments to be approved for use in the UK NHS, robust evidence is required of their impact on health-related quality of life (HRQoL). The National Institute for Health and Care Excellence (NICE) recommends the use of the EQ-5D. Concerns have been raised about the responsiveness of the EQ-5D in the context of multiple sclerosis (MS), however empirical evidence is limited. This research aims to assess the responsiveness of the EQ-5D-3L compared to an MS-specific utility measure, the Multiple Sclerosis Impact Scale Eight Dimensions (MSIS-8D), in people with MS.

METHODS: Analysis was undertaken using data from the UK MS Register (UKMSR), a prospective, longitudinal, cohort study with over 10,000 participants. We investigated changes in EQ-5D-3L and MSIS-8D values before and after (i) commencement of disease-modifying treatment and (ii) onset of new symptoms; and (iii) between time-points with/without a contemporary relapse. Responsiveness was evaluated using standardised response means (SRM), standardised effect sizes (SES) and paired t-tests.

RESULTS: Neither measure appeared responsive to DMT initiation (ie p > 0.05). Both measures were responsive to experiencing a relapse, with the MSIS-8D (mean change -0.047, p = 0.0001, SRM -0.330, SES -0.228) showing greater responsiveness than the EQ-5D (mean change -0.047, p = 0.0054, SRM -0.226, SES -0.139). Neither measure was responsive to experiencing new symptoms (EQ-5D SRM -0.095, SES -0.070; MSIS-8D SRM -0.138, SES -0.118), although the reduction on both measures was statistically significant (p<0.05). In all analyses, 95% confidence intervals for the SRMs indicated that the MSIS-8D was significantly more responsive than the EQ-5D-3L.

CONCLUSIONS: Although the MSIS-8D appears to offer greater responsiveness compared to the EQ-5D-3L, the responsiveness of both measures in this analysis was limited. This adds weight to existing concerns about the ability of QoL measures used in healthcare decision-making to fully capture treatment effects in MS.