Untreated patients with multiple sclerosis: a study of French expert centers.

BACKGROUND Disease modifying therapies (DMTs), have an impact on relapses and disease progression. Nonetheless, many patients with multiple sclerosis (pwMS) remain untreated. The objective of the present study was to determine the proportion of untreated patients with multiple sclerosis (pwMS) followed in expert centers in France and determine the predictive factors of non-treatment. METHODS Retrospective cohort study. Data were extracted from the 38 centers participating in the European Database for Multiple Sclerosis (EDMUS) on 12/15/2018 and pwMS seen at least once during the study period (from June 15, 2016 to June 14, 2017) were included. Results Among the 21,189 pwMS (age 47.1±13.1; EDSS 3.4±2.4), 6,631 (31.3%; 95%CI=30.7-31.9) of the patients were not receiving any DMT. Although patients with a relapsing-remitting course (n = 11,693) were the most likely to receive DMT, 14.8% (95%CI = 14.2-15.4) were still untreated (6.8% never treated). After multivariate analysis among relapsing-remitting pwMS, the main factors explaining never having been treated were not having ≥9 lesions on brain MRI (OR = 0.52 [0.44-0.61]) and lower EDSS (OR = 0.78 [0.74-0.82]). Most patients with progressive MS (50.4% for secondary and 64.2% for primary progressive MS) did not receive any DMT during the study period, 11.6% for secondary and 34.0% for primary progressive MS had never received any DMT. CONCLUSION A significant proportion of pwMS did not receive any DMT, even though such treatments are reimbursed by the healthcare system for French patients. This result highlights the unmet need for current DMTs for a large subgroup of pwMS.