Olfactory threshold as a biomarker of long-term relapse activity in multiple sclerosis.

BACKGROUND

Olfactory threshold (OT) is a marker of short-term inflammatory activity in multiple sclerosis (MS).

OBJECTIVE

To investigate whether OT predicts long-term MS clinical disease course.

METHODS

This was a 6-year prospective longitudinal study on MS patients at the MS clinic Innsbruck. Clinical visits assessing the occurrence of relapses, Expanded Disability Status Scale (EDSS) scores, and disease-modifying treatment (DMT), were conducted biannually. OT testing was performed at baseline (BL), year 1 (Y1), year 2 (Y2) and year 6 (Y6), using the threshold subscore of the "Sniffin' Sticks" test. Cognitive function was assessed by the Symbol Digit Modalities Test.

RESULTS

Of 139 MS patients, 92 were eligible for Y6 follow-up. 68% experienced relapses, 53% EDSS worsening, 29% progression independent of relapse activity (PIRA) and 41% cognitive deterioration. OT scores were lower at BL, Y1 and Y2 in patients requiring DMT escalation. In multivariable analysis, higher OT scores at BL, Y1, Y2 and Y6 were associated with lower risk of relapse (hazard ratio, HR: 0.65-0.92) and EDSS worsening (HR: 0.86-0.89), while no associations were found for PIRA and cognitive deterioration.

CONCLUSIONS

OT is a potential surrogate marker for long-term inflammatory disease activity and DMT failure in MS.

Informations de copyright

Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.

Déclaration de conflit d'intérêts

Declaration of competing interest Klaus Berek: has participated in meetings sponsored by and received travel funding or speaker honoraria from Roche, Teva, Merck, Biogen, Sanofi, Novartis. He is associate editor of Frontiers in Immunology / Section Multiple Sclerosis and Neuroimmunology. Harald Hegen: has participated in meetings sponsored by, received speaker honoraria or travel funding from Bayer, Biogen, Bristol Myers Squibb, Horizon, Janssen, Merck, Novartis, Sanofi-Genzyme, Siemens, Teva, and received honoraria for acting as consultant for Biogen, Bristol Myers Squibb, Novartis, Roche and Teva. He is associate editor of Frontiers in Neurology. Michael Auer: has participated in meetings sponsored by, received speaking honoraria or travel funding from Biogen, Merck, Novartis, Horizon Therapeutics and Sanofi Genzyme. Robert Barket: has participated in meetings sponsored by or received travel grants from, Novartis, Janssen-Cilag and Sanofi-Genzyme. Received honoraria from Janssen-Cilag and Biogen. Franziska Di Pauli: has participated in meetings sponsored by, received honoraria (lectures, advisory boards, consultations) or travel funding from Bayer, Biogen, BMS, Horizon, Merck, Novartis, Sanofi-Genzyme, Teva, and Roche. Jakob Hocher: has nothing to declare. Nik Krajnc: has participated in meetings sponsored by, received speaker honoraria or travel funding from Alexion, BMS/Celgene, Janssen-Cilag, Merck, Novartis, Roche and Sanofi-Genzyme and held a grant for a Multiple Sclerosis Clinical Training Fellowship Programme from the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS). Anne Zinganell: has participated in meetings sponsored by, received speaking honoraria or travel funding from Biogen, Merck, Sanofi-Genzyme, Novartis and Teva. Florian Deisenhammer: has participated in meetings sponsored by or received honoraria for acting as an advisor/speaker for Alexion, Almirall, Biogen, Celgene/BMS, Horizon, Merck, Novartis, Roche and Sanofi. His institution received scientific grants from Biogen, Novartis, and Sanofi. Thomas Berger: has participated in meetings sponsored by and received honoraria (lectures, advisory boards, consultations) from pharmaceutical companies marketing treatments for MS: Allergan, Bayer, Biogen, Bionorica, BMS, Eisai, GW/Jazz, Horizon, Janssen-Cilag, MedDay, Merck, Novartis, Octapharma, Roche, Sanofi-Genzyme, Teva, UPC. His institution has received financial support in the past 12 months by unrestricted research grants (Biogen, Bayer, BMS, Merck, Novartis, Roche, Sanofi Aventis, Teva and for participation in clinical trials in multiple sclerosis sponsored by Alexion, Bayer, Biogen, Merck, Novartis, Octapharma, Roche, Sanofi-Genzyme, Teva. Gabriel Bsteh: has participated in meetings sponsored by, received speaker honoraria or travel funding from Biogen, Celgene/BMS, Lilly, Merck, Novartis, Roche, Sanofi-Genzyme and Teva, and received honoraria for consulting Biogen, Celgene/BMS, Novartis, Roche, Sanofi-Genzyme and Teva. He has received unrestricted research grants from Celgene/BMS and Novartis.