Deakin University

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Redefining the Multiple Sclerosis Severity Score (MSSS): the effect of sex and onset phenotype

journal contribution
posted on 2020-11-01, 00:00 authored by Y Zhou, S B Claflin, J Stankovich, I van der Mei, S Simpson, R H Roxburgh, T Kalincik, L Blizzard, A Lugaresi, R Alroughani, S A Sajedi, H Butzkueven, E Pucci, D L A Spitaleri, F Granella, E Cristiano, B Yamout, S Hughes, R Gouider, J L Sánchez Menoyo, J Olascoaga, C McGuigan, Cameron ShawCameron Shaw, A G Kermode, K Kasa, T Al-Harbi, A Altintas, G Laureys, Y Fragoso, T A Hardy, T Csepany, C A Sirbu, D Decoo, A Sas, J C Alvarez-Cermeño, K Kotkata, J Millán-Pascual, B V Taylor
Background: The Multiple Sclerosis Severity Score (MSSS) is a widely used measure of the disability progression rate. However, the global MSSS may not be the best basis for comparison between all patient groups. Objective: We evaluated sex-specific and onset phenotype–specific MSSS matrices to determine if they were more effective than the global MSSS as a basis for comparison within these subsets. Methods: Using a large international dataset of multiple sclerosis (MS) patient records and the original MSSS algorithm, we constructed global, sex-specific and onset phenotype–specific MSSS matrices. We compared matrices using permutation analysis. Results: Our final dataset included 30,203 MS cases, with 28.9% males and 6.5% progressive-onset cases. Our global MSSS matrix did not differ from previously published data (p > 0.05). The progressive-onset-specific matrix differed significantly from the relapsing-onset-specific matrix (p < 0.001), with lower MSSS attributed to cases with the same Expanded Disability Status Score (EDSS) and disease duration. When evaluated with a simulation, using an onset-specific MSSS improved statistical power in mixed cohorts. There were no significant differences by sex. Conclusion: The differences in the disability accrual rate between progressive- and relapsing-onset MS have a significant effect on MSSS. An onset-specific MSSS should be used when comparing the rate of disability progression among progressive-onset cases and for mixed cohorts.



Multiple sclerosis journal






1765 - 1774


SAGE Publications


London, Eng.







Publication classification

C1 Refereed article in a scholarly journal