We used data from >900 MS patients from the TEMSO and TOWER teriflunomide trials.
Patient-reported health-related quality of life (HRQoL) and fatigue were assessed.
We used four definitions to identify severe MS relapses.
Some 420 patients had relapse(s); most met at least one definition of severe relapse.
Patients experiencing severe relapse(s) had worsening in fatigue and HRQoL