Longitudinal changes in self-reported walking ability in multiple sclerosis.
BACKGROUND
Patient-reported outcomes are increasingly used to understand the clinical meaningfulness of multiple sclerosis disability and its treatments. For example, the 12-item Multiple Sclerosis Walking Scale (MSWS-12) measures the patient-reported impact of the disease on walking ability.


OBJECTIVE
We studied longitudinal changes in walking ability using the MSWS-12 in a cohort of 108 patients with relapsing-remitting multiple sclerosis and moderate-to-severe disability from a single US center cohort study investigating multiple sclerosis symptoms and physical activity.


METHODS
The MSWS-12 was completed every 6 months over 2 years together with self-reported measures of disease impact on daily life (Multiple Sclerosis Impact Scale) and walking disability (Patient Determined Disease Steps scale).


RESULTS
The results revealed a high frequency of self-reported changes in walking ability at the individual level, affecting approximately 80% of patients for all four time periods. MSWS-12 scores remained stable at the group level for all four time periods. The magnitude of observed changes at the individual level was higher than the proposed minimal clinically important differences of 4 or 6 points and correlated better with Multiple Sclerosis Impact Scale physical scores than psychological scores, but little with self-reported Patient Determined Disease Steps Scale scores.


CONCLUSIONS
This novel finding of frequent fluctuations in self-reported walking ability is new and requires further investigation.
Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
Robert W
RW
Motl
Clinical Development Group, Biogen, Cambridge, Massachusetts, United States of America.
Norman
N
Putzki
Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
Lara A
LA
Pilutti
Clinical Development Group, Biogen, Cambridge, Massachusetts, United States of America.
Diego
D
Cadavid
D000328:Adult; D003710:Demography; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000503:physiopathology; D015203:Reproducibility of Results; D057566:Self Report; D011795:Surveys and Questionnaires; D016138:Walking; D055815:Young Adult