Walking speed, rather than Expanded Disability Status Scale, relates to long-term patient-reported impact in progressive MS

Abstract

To study the relationships between 1–2 year changes in well-known physician-rated measurements (Expanded Disability Status Scale (EDSS), Timed 25-Foot Walk (T25FW), 9-Hole Peg Test (9HPT)) and the long-term (≥ 5 years) outcome in patient-reported outcome (PRO) measures (Multiple Sclerosis Impact Scale (MSIS-29), Multiple Sclerosis Walking Scale (MSWS-12)) that reflect the patient-perceived impact of disease, in progressive MS. We selected all progressive patients having at least two complete visits within 1-2 years, from a larger cohort of prospectively-followed MS patients. These were invited for another visit, at least 5 years later, consisting of another series of similar examinations, plus 2 PRO scales: the MSIS-29 and MSWS-12. We explored associations between early changes in physician-rated measurements and the long-term outcome as per the PRO measures. In this study,134 patients fulfilled the selection criteria. We found that early change in T25FW was the only physician-rated change that was significantly related to long-term physical impact experienced by the patient, as was assessed by MSIS-29 (Kruskal-Wallis test: χ²=7.8, p=0.020). Early T25FW change, and to a lesser degree early 9HPT change, were significantly related to the reported long-term walking limitations, as assessed by MSWS-12 (Kruskal-Wallis test: χ²=13.8 and p=0.001 for T25FW, χ²=6.5 and p=0.038 for 9HPT). None of the early physician-rated changes were related to the long-term psychological impact experienced by the patient. Early changes on physician-rated scales do have long-term impact in terms of potentially predictive value of outcomes for groups of patients in progressive MS, regarding walking limitations and more global physical impact. Surprisingly, early change in T25FW, rather than early change in EDSS, was significantly associated with longer-term patient-reported disease impact. Our study data support the value of using early physician-rated examinations in clinical trials in progressive MS.