Contribution of impaired mobility to patient burden in multiple sclerosis

Multiple sclerosis (MS) is frequently diagnosed during a person's most productive years, and because life expectancy for patients with MS approaches that of the general population, MS is associated with a considerable economic burden from medical costs and lost productivity. In addition, there is a substantial negative impact on quality of life (QOL) and activities of daily living (ADL). While change in walking ability often is the most visible sign of MS, and the classic clinical manifestation, few studies have evaluated the relationship between mobility impairment and patient-reported outcomes like ADL and QOL. The purpose of this article is to review the contribution of mobility impairment to patient-reported outcomes in persons with MS.

Searches of PubMed were performed to identify studies from the MS literature, from January 1980 through November 2008, that evaluated the contribution of mobility to the patient burden of disease. Abstracts identified using the search terms 'multiple sclerosis AND (walking OR mobility)' in combination with the terms 'burden,' 'costs,' 'quality of life,' 'activities of daily living,' 'independence,' and 'productivity' were reviewed for relevancy for inclusion.

Although impaired mobility is more apparent with greater disease duration and at higher levels of disability, it may be present even in the early stages of MS. Maintaining mobility is ranked as one of the highest priorities among patients with MS, regardless of disease duration or disability level. Several studies have demonstrated that loss of mobility contributes to a substantial patient burden. The statistical technique of path analysis has shown how difficulty walking significantly affects physical activity in patients with MS. Impaired mobility is associated with reductions in QOL, ADL, and productivity. The primary concern related to patient independence among persons with MS, regardless of their status, is loss of mobility. It should be noted that limitations inherent in some of the studies, including heterogeneity in methodology and MS populations, may limit their generalizability.

These findings highlight the need for more comprehensive assessments of walking impairment in patients with MS and further evaluation from the patient's perspective.