[Multiple sclerosis without treatment: characteristic features of 70 untreated patients in a cohort of 1187 patients]

First treatment protocols for multiple sclerosis (MS) have been established in France for over 15 years. Presently, a large majority of patients are treated, or has been treated in the past years, with one or more disease modifying drugs. However, despite a long-term follow-up, a certain patients remain untreated.

The aim of this study was to determine in a large cohort the proportion of patients who never received any medication for MS and to analyze their profiles and reasons for no treatment.

We studied a cohort of 1187 MS patients followed in a French (Alsace) cohort, all included in the EDMUS (European database for Multiple Sclerosis). We then performed a retrospective study on patients followed from at least 5 years (724 patients) and retained those who had never received MS medication.

Seventy patients (9.8% of the whole cohort) corresponded to the inclusion criteria. They were 57 women and 13 men, mean age 54.9 years (range 33-81). The mean duration of the disease was 20.6 years (range 5-56). MS was of relapsing remitting type in 46 patients (65.7%), primary progressive in 11 patients (15.7%) and secondary progressive in 13 patients (18.6%). In patients with relapsing remitting disease, the annualized relapse rate was 0.33 (range 0.08-1). Mean EDSS was 3.4 after a mean follow-up of 20.6 years. Progression index was 0.16 without any differences between progressive and relapsing remitting forms (0.15 and 0.16 respectively). Reasons for not treating were: lack of disease activity (65.8%), very slow disease progression (10%), patient's initial decision followed by very slow progression (14.2%), contraindication for treatment in patients with longstanding progressive disease (10%). There were also patients (4.3%) whose initially well-stabilized disease recently became active again, leading to reconsideration about starting treatment.

After a mean follow-up of 20 years, the proportion of treatment-free patients was around 10%. Most of these patients had a relapsing remitting form with a low rate of relapse or a progressive form with very slow progression.