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Updated: Oct 6, 2025

A Method of Trigonometric Modelling of Seasonal Variation Demonstrated with Multiple Sclerosis Relapse Data
Published on: December 9, 2015
Characterizing Long-term Disability Progression and Employment in NARCOMS Registry Participants with Multiple
Amber Salter1, Samantha Lancia1, Gary Cutter2
1Division of Biostatistics, School of Medicine, Washington University in St Louis, St Louis, MO, USA (AS [now at UT Southwestern Medical Center], SL).
Background:
Delayed-release dimethyl fumarate (DMF) is effective in relapsing-remitting multiple sclerosis (RRMS), but long-term effects of DMF on disability and disease progression in clinical settings are unknown. We evaluated disability and employment outcomes in persons with RRMS treated with DMF for up to 5 years.
Methods:
This longitudinal study included US North American Research Committee on Multiple Sclerosis (NARCOMS) Registry participants with RRMS reporting DMF initiation in fall 2013 through spring 2018 with 1 year or more of follow-up. Time to 6-month confirmed disability progression (≥1-point increase in Patient-Determined Disease Steps [PDDS] score) and change in employment status were evaluated using Kaplan-Meier analysis. Participants were censored at last follow-up or at DMF discontinuation, whichever came first.
Results:
During the study, 725 US participants with RRMS had at least 1 year of DMF follow-up data, of whom most were female and White. At year 5, 69.9% (95% CI, 65.4%-73.9%) of these participants were free from 6-month confirmed disability progression, and 84.7% (95% CI, 78.6%-89.2%) were free from conversion to secondary progressive MS. Of 116 participants with data at baseline and year 5, most had stable or improved PDDS and Performance Scales scores over 5 years. Of 322 participants 62 years and younger and employed at the index survey, 66.0% (95% CI, 57.6%-73.1%) were free from a negative change in employment type over 5 years.
Conclusions:
Most US NARCOMS Registry participants treated up to 5 years with DMF remained free from 6-month confirmed disability progression and conversion to secondary progressive MS and had stable disability and employment status. These results support the long-term stability of disability and work-related outcomes with disease-modifying therapy.

