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


Zhou, Y and Claflin, SB and Stankovich, J and van der Mei, I and Simpson Jr, S and Roxburgh, RH and Kalincik, T and Blizzard, L and Lugaresi, A and Alroughani, R and Sajedi, SA and Butzkueven, H and Pucci, E and Spitaleri, D and Granella, F and Cristiano, E and Yamout, B and Hughes, S and Gouider, R and Sanchez Menoyo, JL and Olascoaga, J and McGuigan, C and Shaw, C and Kermode, AG and Kasa, K and Al-Harbi, T and Altintas, A and Laureys, G and Fragoso, Y and Hardy, TA and Csepany, T and Sirbu, CA and Decoo, D and Sas, A and Alvarez-Cermeno, JC and Kotkata, K and Millan-Pascual, J and Taylor, BV, Redefining the Multiple Sclerosis Severity Score (MSSS): the effect of sex and onset phenotype, Multiple Sclerosis Journal, (October) pp. 1-10. ISSN 1352-4585 (2019) [Refereed Article]

Copyright Statement

Copyright 2019 The Authors

DOI: doi:10.1177/1352458519881994


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.

Item Details

Item Type:Refereed Article
Keywords:multiple sclerosis, Multiple Sclerosis Severity Score, disability progression, onset phenotype
Research Division:Biomedical and Clinical Sciences
Research Group:Neurosciences
Research Field:Central nervous system
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Zhou, Y (Mr Yuan Zhou)
UTAS Author:Claflin, SB (Dr Suzi Claflin)
UTAS Author:van der Mei, I (Professor Ingrid van der Mei)
UTAS Author:Simpson Jr, S (Dr Steve Simpson JR)
UTAS Author:Blizzard, L (Professor Leigh Blizzard)
UTAS Author:Taylor, BV (Professor Bruce Taylor)
ID Code:135658
Year Published:2019
Web of Science® Times Cited:5
Deposited By:Menzies Institute for Medical Research
Deposited On:2019-11-07
Last Modified:2022-08-23

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