To determine prognostic factors of disability in multiple sclerosis (MS), that is, (1) identify determinants of the dynamics of disability progression; (2) study the effectiveness of disease-modifying treatments (DMTs); (3) merge determinants and DMTs for creating patient-centred prognostic tools and (4) conduct an economic analysis.

Individuals registered in the French Observatoire Francais de la Sclérose en Plaques (OFSEP) database were included in this OFSEP-high definition cohort if they had a diagnosis of MS, were ≥15 years old and had an Expanded Disability Status Scale (EDSS) score

A cohort of 2842 individuals, 73.4% women, mean (SD) age of 42.7 (11.6) years, median disease duration of 8.8 years, has been recruited from July 2018 to September 2020. The course of MS was relapsing remitting in 67.7%, secondary progressive in 11.9%. The mean annual relapse rate was 0.98. The disease-modifying treatment received was highly effective therapy in 50.3% and moderately effective therapy in 30.7%.

The participants will be followed until December 2026. Disease course up to four landmarks will be examined as predictors of disease progression: (1) diagnosis of MS; (2) relapse activity worsening and independent progression; (3) any recent disease activity and (4) any visit with absence of disease activity in the past 5 years. The marginal effectiveness and tolerability of treatments will be assessed. Stratified algorithms will be proposed for medical decision-making. Economic evaluation of disease cost and cost-effectiveness of new DMTs will be conducted from a public payer perspective.

NCT03603457.