For neurologists and patients, it appears that one major unmet need, beside of course a cure to multiple sclerosis (MS), is to better appreciate the causal factors of disease progression, and even to obtain reliable predictive tools that could apply on the individual level and at different key moments in the disease course.

The overarching objective of the OFSEP-HD cohort is to determine prognostic factors of the evolution of disability in MS in real life, looking at disease characteristics, care practices potentially modifying the evolution of the disease since MS clinical onset and along specific post-onset landmarks. This general framework leads to study 3 specific research objectives:

1. To identify determinants (socio-demographic characteristics, clinical characteristics, health related quality of life (QoL), changes in classification, and biomarkers) for the progression of MS disease and its consequences;
2. To study the effectiveness of treatments in real life;
3. To merge both determinants and treatments for creating patient-centered prognostic tools for identifying specific subgroups of patients and helping making decision to start, maintain or adapt care management.

To achieve these objectives, the OFSEP (The French multiple sclerosis registry) infrastructure, managed under a quality insurance system, offers a unique opportunity for the first time in France to create a large cohort of MS cases, providing high-definition and sequential multimodal data.

Inclusion Criteria:

• Diagnosis of multiple sclerosis according to the most recent criteria at entry into the HD cohort
• Followed in one MS Clinical Reference Centre (CRC SEP)
• Newly diagnosed after the study start or
• If MS onset occurred before study start, regular follow-up in a CRC SEP
• Irreversible disability ≤ 7.0 (permanent use of a wheelchair) on EDSS at inclusion in the study

Non-inclusion Criteria:

• Inability to answer questionnaires
• Pregnant women at the time of inclusion

All MS patients from MS Clinical Reference Centre (CRC SEP).