Detection of disability worsening in relapsing-remitting multiple sclerosis patients: a real-world roving Expanded Disability Status Scale reference analysis from the Italian Multiple Sclerosis Register
Abstract
Background and purpose
In relapsing-remitting multiple sclerosis patients (RRMS) disability progressively accumulates over time. To compare the cumulative probability of 6-month confirmed disability-worsening events using a fixed baseline or a roving Expanded Disability Status Scale (EDSS) reference, in a real-world setting.
Methods
A cohort of 7964 RRMS patients followed for 2 or more years, with EDSS scores recorded every 6 months, was selected from the Italian Multiple Sclerosis Register. The overall probability of confirmed disability-worsening events and of confirmed disability-worsening events unrelated to relapse was evaluated using as reference a fixed baseline EDSS score or a roving EDSS score in which the increase had to be separated from the last EDSS assessment by at least 6 or 12 months.
Results
Using a fixed baseline EDSS reference, the cumulative probability of 6-year overall confirmed disability-worsening events was 33.2%, and that of events unrelated to relapse was 10.9% (33% of overall confirmed disability-worsening events). Using a roving EDSS, the proportions were respectively 35.2% and 21.3% (61% of overall confirmed disability-worsening events).
Conclusions
In a real-world setting, roving EDSS reference scores appear to be more sensitive for detecting confirmed disability-worsening events unrelated to relapse in RRMS patients.
Disclosure of conflicts of interests
P.M., C.B., C.S., and V.L. declare no conflict of interest. P.I. has served on scientific advisory boards for Biogen Idec, Bayer, Teva, Roche, Merck Serono, Novartis, and Genzyme and has received funding for travel and/or speaker honoraria from Sanofi Aventis, Genzyme, Biogen Idec, Teva, Merck Serono, and Novartis. M.T. has served on scientific advisory boards for Biogen, Novartis, Roche, and Genzyme; has received speaker honoraria and travel support from Biogen Idec, Sanofi Aventis, Merck Serono, Teva, Genzyme, and Novartis; and has received research grants for her institution from Biogen Idec, Merck Serono, and Novartis.
Open Research
Data availability statement
The datasets analyzed for this study are available from the corresponding author on reasonable request.
