Description of the OFSEP cohort on 8 December 2024

The patients monitored within the framework of OFSEP come from the 42 centers participating in the project corresponding to 48 databases of which 2 includes only NMOSD patients. Each center recruits patients either within a hospital or from a healthcare network.

All data are entered using EDMUS, a specialist medical file enabling the monitoring of multiple sclerosis (MS) patients in routine medical practice.

On 15 June 2013, in an effort to harmonize collection methods and improve data quality, a precise set of data (minimal data) was defined for systematic collection: personal and sociodemographic data, clinical data (neurological episodes, clinical evaluations, irreversible disability), para-clinical data (MRI, etc.) and therapeutic data (disease-modifying treatments). These data can also be used for research purposes.

Number of patients

By 8 December 2024, 42 centers were participing in the compilation of the OFSEP clinical database..

The database comprises 93,680 files, 68,065 (72.7%) of which are for patients who have consulted since 15 June 2013 and for which the minimal data has been collected. Each center has an average of 1,912 files (standard deviation ± 2,293).

Number of patients registered on EDMUS per centre

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Number of patients registered on EDMUS per centre

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Since patients may consult doctors in different cities during the course of their lives, it is possible that some have several clinical files: these are what we call duplicates. Furthermore, the MS diagnosis can be difficult to confirm, and the elements in the computer file do not enable diagnostic certainty. Thus, in the presentation below, duplicates, uncertain diagnosis files and patients with acute neuromyelitis optica (Devic's disease) or related neurological syndromes, radiologically isolated syndromes (RIS) or with antibody anti-AQP4 or with antibody anti-MOG have been excluded. A total of 74,713 patients are thus included in the analysis.

Age and gender of patients

Distribution of patient age at disease onset

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Distribution of patient age at disease onset

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A majority of women (N=52,955; 71%) compared with men (N=21,758; 29%).

The age of disease onset varies from 1 to 83 years, but the disease starts in most patients between the ages of 20 and 39 (N=48,176; 64.5%). 4,038 patients (5.4%) were identified as having MS before the age of 18 and 5,204 (7%) were "late" starters, i.e. after the age of 50 years.

Disease courses

In most cases, the clinical onset of the disease is characterized by a relapse (also called “attack”) (N=66,479; 89%), at an average age of 31.5 years (± 10.2); only 11.1% of patients (N=8,234) have an onset disease with a primary progressive course, and much later (43.2 years old ± 11.2 years).

The majority of patients (68.3%) have a relapsing-remitting MS and 20.7% have a secondary progressive MS.

Distribution of disease courses

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Distribution of disease courses

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Patient medical follow-up

The duration of the disease, i.e. the time between the first neurological episode and the last consultation, varies from 0 to 77.8 years. Half of the patients have been followed for more than 13 years and 25% for more than 22 years.

Distribution of disease duration

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Distribution of disease duration

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Distribution by date of last clinical evaluation

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Distribution by date of last clinical evaluation

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On 8 December 2024, 50% of patients had consulted for the last time during the 3.1 years prior to export, and 30.9% during the past year. All these patients can be considered as being part of the active patient population of the participating neurology departments, and their data are therefore updated regularly. Conversely, 25% of patients had not consulted within the past 10 years or longer.

In view of the progressive nature of the disease, the distribution between the different courses is highly correlated with the duration of the disease and represents only the state of the patients followed by OFSEP on 8 December 2024.

Distribution of disease courses according to disease duration

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Distribution of disease courses according to disease duration

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Relapsing-remitting MS patients are very highly represented when the disease first starts. The proportion of relapsing-remitting MS patients falls as disease duration increases, since more patients develop a secondary progressive course of the disease.

Distribution of disease courses according to patient age at the last clinical evaluation

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Distribution of disease courses according to patient age at the last clinical evaluation

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Using a similar process, the distribution of disease courses varies according to patient age. This is compounded by the fact that primary progressive courses generally start later than the other courses. Thus, at the age of 30, 96% of patients have relapsing-remitting MS whereas at 70, 71.7% of patients have a progressive course (25.9% primary progressive and 45.7% secondary progressive).

Recruitment dynamics

Capture rate of patients by OFSEP

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Capture rate of patients by OFSEP

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The time between the onset of the disease and the date of patient inclusion by a neurologist participating in the OFSEP project is described as the "capture period". The first year after onset of the disease, 39.6% of patients with a remitting course initially and 15% of patients with a primary progressive course are taken on by an OFSEP neurologist. Half of the patients with a remitting course initially and half of the patients with a primary progressive course are captured by OFSEP after 2.5 and 4.3 years respectively. Ten years after disease onset, close to 75% of OFSEP patients have been captured, for both remitting and progressive courses.

Symptoms of the first neurological episode

For most patients (47.3%), the first neurological episode involved only an attack of the long tracts. An attack of the long tracts corresponds to walking or balance difficulties, motor disorders (upper and lower limbs), sensory disorders (upper and lower limbs, torso, Lhermitte's sign), urinary or bowel disorders and sexual disorders. Optic neuritis alone is the only symptom of disease onset in 18.1% of patients. Brain stem disorders alone affected 10.7% of patients: this involves oculomotor disorders, vestibular or cochlear disorders, motor and sensory disorders of the face and speech or swallowing problems. Finally, 17.9% of patients had a combination of symptoms during the first episode of their disease.

Distribution of symptoms of the first neurological episodes

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Distribution of symptoms of the first neurological episodes

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First inter-attack interval

Distribution of period between the first inter-attack interval for relapsing-remitting patients

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Distribution of period between the first inter-attack interval for relapsing-remitting patients

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Among the patients with a relapsing-remitting course (N=39,955), 25% had a second relapse within a year of the first one, half after 1.8 years and 25% after 4.7 years.

• Relapsing-remitting courses

Repartition of ongoing disease-modifying treatments for relapsing-remitting patients

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Repartition of ongoing disease-modifying treatments for relapsing-remitting patients

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There are 23,081 patients with relapsing-remitting MS in the active patient population (74.2%). Among them, 9.1% are treatment naive, 6.3% received a treatment stopped more than 2 years before the last consultation and 5.6% received a treatment stopped less than 2 years before the last consultation. Highly effective treatments are the most common (50.1%), ahead of moderately effective treatments (27.7%). Among the most frequently used treatments, two are highly effective treatments (ocrelizumab 18.1%; natalizumab 11.5%) and one is moderately effective treatment (teriflunomide 10%).

• Secondary progressive MS

There are 5,263 patients with secondary progressive MS in the active patient population (16.9%). Among them, 8.6% are treatment naive, 34% received a treatment stopped more than 2 years before the last consultation and 8.5% received a treatment stopped less than 2 years before the last consultation. Patients receiving treatment are mainly on highly effective treatments (35.4%) or moderately effective treatments (36.7%). Among the most frequently used treatments, two are highly effective treatments (ocrelizumab 18.7%; rituximab 10.1%).

Repartition of ongoing disease-modifying treatments for secondary progressive

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Repartition of ongoing disease-modifying treatments for secondary progressive

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• Primary progressive MS

Repartition of ongoing disease-modifying treatments for primary progressive patients

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Repartition of ongoing disease-modifying treatments for primary progressive patients

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There are 2,764 patients with primary progressive MS in the active patient population (8.9%). These are the least-treated patients: 26.1% are treatment naive, 24% received a treatment stopped more than 2 years before the last consultation and 6.3% received a treatment stopped less than 2 years before the last consultation. Highly effective treatments are the most common (32.3%), ahead of drugs with no MA for MS (4.8%). Among the most frequently used treatments, two are highly effective treatments (rituximab 20.7%; ocrelizumab 9.7%).

Description of the available MRI on the OFSEP’s database on 15 December 2021

On 15 December 2021, 26 centers have imported OFSEP’s MRI data on the Shanoir database. MRI were acquired by around 250 imaging centers, public and private.

The MRI’s protocol of 5,949 patients with different disease courses has been imported to the Shanoir-OFSEP database. Around 60% of patients had cerebral MRI at least two time point. Similarly, 45% of patients had multiple time points of spinal cord MRI.

RIS: radiologically isolated syndromes, CIS: clinically isolated syndromes (CIS), RRMS: relapsing-remitting MS, SPMS: secondary progressive MS, PPMS: primary progressive MS, NMOSD: neuromyelitis optica spectrum disorder.

In total, more than 200,000 sequences (corresponding to more than 20,000 studies) are available, most of which are cerebral sequences. The cerebral and spinal cord sequences recommended by the OFSEP protocol are represented below.

Description of the OFSEP sample collection on 8 December 2024

The OFSEP sample collection is composed of biological samples taken in patients from biological cohorts: radiological isolated syndrome (RIS), first attack MS, untreated relapsing-remitting MS (RRMS), untreated primary progressive MS (PPMS), neuromyelitis optica spectrum disorder (NMOSD), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), acute disseminated encephalomyelitis (ADEM), progressive multifocal leukoencephalopathy (PML) and MS/NMOSD/MOGAD with Covid-19. The RRMS patients, secondary progressive MS (SPMS) and PPMS included in the OFSEP HD cohort are also sampled.

For the biological cohorts, blood samples (serum, plasma, whole blood and peripheral blood mononuclear cells (PBMC)), cerebrospinal fluid and saliva are collected by the participating centers, using OFSEP sampling kits. For the OFSEP HD cohort, only blood tubes are collected.

On 8 December 2024, 5,111 patients have been sampled. The derivative biological samples are stored in the 28 OFSEP-participating biobanks.

* Some patients could be counted several times if they enter an new cohort during the follow-up (ex : RIS => First attack)

** Including patients from the OFSEP High Definition cohort (patients with only blood samples)

*** Closed collection

Blood = serum + EDTA plasma + whole blood for DNA extraction

PBMC = Peripheral blood mononuclear cells

CSF = Cerebrospinal fluid

OFSEP consent

Legally, any entity wanting to collect medical data for research purposes must first obtain informed consent from the subjects. This means that consent must be obtained without any constraint and after properly informing the subjects.

The consent form that each doctor participating in the project gives to his patients is intended to find out whether or not they accept that their data and biological samples are collected and that certain uses may be made of them (genetic analyses, etc.).

Signing an OFSEP consent form changes nothing in terms of the patient's care. No additional consultations or examinations are required.

Participation is voluntary and at the patient's own discretion. The patient's signature authorizes OFSEP to use his data and biological samples in an anonymous manner, thus protecting patient confidentiality. It does not represent a definitive commitment by the patient, who can change his mind at any time and ask to be withdrawn from the project.

If participation is refused immediately or consent is later withdrawn at any time, the patient will continue to receive the best possible care.

Are there other consent forms to be signed?

The OFSEP consent form covers the research actions related to the OFSEP cohort.

Additional studies may be set up (see "our missions" and "studies"). For studies whose scientific purpose does not come under OFSEP's initial objective or for studies that require additional consultations, examinations or questionnaires, an informed consent form must be signed by patients willing to participate.

OFSEP only processes non-nominative data to which only trained, approved personnel have access.

Data can only be transmitted to a third party for the purposes of a scientific project. Before any transmission, the project must have obtained all the mandatory regulatory authorizations, have been validated by OFSEP's Scientific Board and approved by OFSEP's Steering Committee. Only data that are essential to the project are provided and advanced encryption techniques are implemented to protect against possible hack attempts.

OFSEP is not authorized to collect the social security number (NIR) of patients, but is considering submitting a request to do so. In order to anticipate a future authorization that the health authorities may grant, OFSEP already requests consent from patients to be able to use this number and the associated health insurance data in the future. Even with the patient's consent, until OFSEP obtains the necessary authorizations, the patient's NIR will not be collected or used.

The reason for using the NIR is to enable more detailed evaluation of the patients' treatment protocols according to their clinical state and to conduct studies on the basis of this information, which is generally difficult to obtain in routine practice.

The use of health insurance fund data will enable the study of groups of patients while ensuring data confidentiality. Such data will never be used to analyze individual data or to communicate individual or nominative data to third parties. The use of such data is governed by very strict legislation and demands specific authorizations.

The gene pool can influence the occurrence of MS; we already know that there are family forms of the disease.

Analysis of the genes of MS patients is a fundamental step in identifying the genetic factors involved in triggering the disease and its action; in turn, this should help to develop new treatments.

As proponent of the OFSEP project within which the national OFSEP database is developed, the Eugène Devic EDMUS Foundation against Multiple Sclerosis acts as joint controller of patient personal data processing with the company EDMUS Services SAS, its subsidiary in charge of database management. The personal data processing of patients is based on the legitimate interest of the data controller, and on the intended purpose of public interest of the research project. As part of this co-responsibility :

• the EDMUS Foundation is responsible of implementing regulatory formalities of the processing (authorization request from the French data protection authority 'CNIL' or declaration of compliance with a reference methodology) and the information notification to patients (through the neurologists participating in the project) under the necessary regulatory conditions.
• the EDMUS Services SAS is responsible of implementing requests of the exercise of rights formulated by patients (rights of access, rectification, limitation, erasure and portability of personal data, right of opposition to personal data being processed ; all requests must be made in writing addressed by each patient to their neurologist) and the management of potential data breaches (report of the type and consequences of the data breach, description and implementation of measures taken against the violation, information from CNIL, etc.).

As joint data controllers of the OFSEP national database, the Eugène Devic EDMUS Foundation against Multiple Sclerosis and EDMUS Services have appointed a common contact, the Data Privacy Officer of EDMUS Services, contactable at This email address is being protected from spambots. You need JavaScript enabled to view it.

The OFSEP cohort has registered an authorization request for biomedical research with the CNIL (France's national data protection authority). This authorization concerning the collection of clinical data and biological samples was granted under number 914066 in May 2014; the authorization concerning the collection of MRI data was granted in May 2015. The updated protocol in line with the GDPR has received a positive response of the Ile-de-France VI Ethics Committee in February 2020.

Download the OFSEP consent and information notes (in French)

Download the OFSEP information brochure (in French)

Download the OFSEP Poster (in French)