The impact of increasing neurological disability of multiple sclerosis on health utilities: a systematic review of the literature.

BACKGROUND: Multiple sclerosis (MS) is a debilitating disease, accompanied by neurological symptoms of varying severity. Utilities are a key summary index measure used in assessing health-related quality of life in individuals with MS.
OBJECTIVES: To provide a systematic review of the literature on utilities of relapsing-remitting MS (RRMS) and secondary progressive MS (SPMS) patients and to review changes in utilities associated with the increasing neurological disability of different stages of MS, as measured by the Expanded Disability Status Scale (EDSS).
METHODS: Employing pre-defined search terms and inclusion/exclusion criteria, systematic searches of the literature were conducted in EMBASE, MEDLINE, PsycINFO, the Health Economic Evaluation Database (HEED), and the NHS Economic Evaluations Database (NHS/EED). Proceedings for the International Society for Pharmacoeconomics and Outcomes Research (ISPOR), the European Society for Treatment and Research in MS (ECTRIMS), the American Society for Treatment and Research in MS (ACTRIMS), and the Latin American Society for Treatment and Research in MS (LACTRIMS) were reviewed in addition to the UK National Institute for Health and Clinical Excellence website and the table of contents of PharmacoEconomics and Value in Health.
RESULTS: This review identified 18 studies reporting utilities associated with health states of MS. Utilities ranged from 0.80 to 0.92 for patients with an EDSS score of 1, from 0.49 to 0.71 for patients with an EDSS score of 3, from 0.39 to 0.54 for patients with an EDSS score of 6.5, and from -0.19 to 0.1 for patients with an EDSS score of 9. LIMITATIONS: Several of the studies reviewed relied on data from patient organizations, which may not be fully representative of the general patient populations. Additionally, the majority of the studies relied on retrospective data collection.
CONCLUSIONS: Utilities decrease substantially with increasing neurological disability. Cross-country differences are minimal with utility scores following a similar pattern across countries for patients at similar disease severity levels. This consistency in findings is noteworthy, as there is a reliable evidence base for selecting utility values for economic evaluation analyses. However, more research is needed to explore potential differences in utilities between RRMS and SPMS patients.