Patient reported outcomes in a secondary progressive MS cohort related to cognition, MRI and physical outcomes.

Background: Patient-reported outcomes (PROs) are increasingly being used as outcomes in secondary progressive multiple sclerosis (SPMS) trials. We examined how PROs reflect disease burden in SPMS.

Methods: In this observational prospective study, 65 SPMS patients were examined by five different PROs (Fatigue Scale Motor Cognition (FSMC), Multiple Sclerosis Impact Scale version 2 (MSIS-29v2), 36-Item Short Form Health Survey version 2 (SF-36v2), EQ-5D-5L and Work Productivity and Activity Impairment Questionnaire: Multiple Sclerosis version 2.0 (WPAI:MS)); two different rating scales, Multiple Sclerosis Impairment Scale (MSIS) and Expanded Disability Status Scale (EDSS); functional tests of mobility (Timed-25-Foot Walk (T-25FW), 6-Spot Step Test (6-SST) and (9-Hole Peg Test (9-HPT)); cognitive tests (Symbol Digital Modalities Test (SDMT) and Brief Visuospatial Memory Test-Revised (BVMT-R)); and multimodal Magnetic Resonance Imaging (MRI).

Results: When the PROs were divided into physical and psychological subscores, the PRO physical subscores of FSMC, MSIS-29v2 and SF-36v2 correlated with physical rating scales (EDSS, MSIS) and physical measures of upper (9-HPT) and lower extremity function (T-25FW and 6-SST)) (p = 0.04-0.0001). 9-HPT correlated the least with physical subscores of PROs but showed the strongest correlation with activity impairment (subscore of WPAI:MS). In contrast, psychological PRO subscores of FSMC, MSIS-29v2 and SF-36v2 did not reflect the cognitive outcomes (SDMT and BVMT-R), although the cognitive scores correlated with disease burden indicated by MRI lesion volumes. The psychological PRO subscores did not correlate with fatigue, physical and MRI outcomes either.

Conclusion: Correlation between PRO physical subscores and physical outcomes supports PROs as potentially useful clinical endpoints in SPMS. The results of this study indicate that patients with SPMS highly perceive their mobility on function of their lower extremities, while they perceive their daily activities highly dependent on function of the upper extremities. Psychological subscores of MS specific PROs may be less suitable as surrogate markers for the cognitive status and should be considered as a mental quality of life measurement independent of disease burden.