Objective: To investigate which changes in different clinical outcome measures contribute most to increased disease impact, as reported by the patient, in progressive multiple sclerosis (MS).
Methods: From a cohort of prospectively-followed MS patients, we selected progressive patients with two visits, 4-6 years apart. We assessed long-term changes on the Expanded Disability Status Scale (EDSS), Timed 25-Foot Walk (T25FW), 9-Hole Peg Test (9HPT) and Guy's Neurological Disability Scale (GNDS). We defined the presence or absence of clinically meaningful change by using the Multiple Sclerosis Impact Scale (MSIS-29) as an anchor measure. We also studied change on recently identified sub-scales of GNDS.
Results: Change on GNDS (especially the spinal-plus subscale) contributed most to increased disease impact. Also change on the T25FW contributed largely. Specific profiles of change in T25FW and MSIS seemed to exist (generally, a lower increase in disease impact in patients with longer disease duration and higher baseline impact/disability). In some patients a dissociation existed between increased impact, according to the MSIS-29, and objective physical worsening of the T25FW.
Conclusion: These results support using GNDS (particularly the spinal-plus domain) and T25FW in outcome measurement in progressive MS. We suggest there is a relation between baseline clinical characteristics and an increased impact at follow-up. This may have implications for patient selection in trials for progressive MS.
Keywords: Clinical outcome; disability tests; disease progression; multiple sclerosis; outcome measurement; patient reported outcome; study design.
© The Author(s), 2014.