Most data regarding the use of disease-modifying therapies (DMTs) in multiple sclerosis (MS) comes from clinical series or regional databases that have a risk of recruitment bias. French health administrative data offers the significant advantage of being extensive in regards to both MS population coverage and DMT prescriptions.

To describe patterns of DMTs usage at the level of the entire French population of MS patients from 2010 to 2015.

MS patients were identified during a 6-year study period via the French national health data system (covering 97% of the general population) and characteristics of patients who received at least one treatment were compared to those that never received treatment over the indicated period. A state sequence analysis was performed to study in a longitudinal way MS patients who started DMTs in 2010 and then to classify them into groups of similar therapeutic patterns. DMTs were categorized into first-line, second-line and off-label use, and included untreated periods for at least six months. Groups that were obtained were described and compared using a multinomial logistic regression.

A total of 112,415 patients with MS were identified, of whom 54.0% received at least one DMT over the 6 years. The probability of being treated significantly decreased with age. Comorbidities and physical limitations appeared to be more frequent in not treated patients than in treated patients. Significant differences were also found between the two groups regarding the use of healthcare services (hospitalizations and visits to general practitioner, neurologist and nurse). Based on the 6-year therapeutic sequences, a four-cluster typology was obtained on the 4,474 patients who started a DMT in 2010. The first group which consisted of more than half of the patients (57.0%) mainly used first-line DMTs. The second group (13.1%) represented patients with second-line DMTs whereas the third group (7.3%) was comprised of off-label users and the last group (22.6%) was composed of MS patients who received no or minimal treatments. Classification into one of these groups was associated with patient's age, long-term disease status, pregnancy occurrence, estimated level of disability, levels of care (visits to a neurologist, nurse and/or physiotherapist and hospital/rehabilitation stays) and occurrence of death.

The exhaustive population-based dataset from the French national health data system gave the opportunity to provide a detailed description regarding the use of DMTs for MS at national level. The innovative method of state sequence analysis allowed obtaining four homogeneous groups of patients among thousands of longitudinal therapeutic sequences. The predominant place of first-line treatments was confirmed even if the type of first-line treatments has probably changed since 2015.