OBJECTIVES: In patients with RMS, assess the impact of relapse(s) leading to hospitalization on Health-Related Quality of Life (HR-QoL), fatigue and Health Care resource utilisation. METHODS: TEMSO (N=1088) was designed to assess efficacy and safety of teriflunomide, a novel oral disease modifier, in RMS patients. Patients with no relapse, patients with relapse(s) not leading to hospitalisation and patients with at least one relapse leading to hospitalisation were analysed. The following patient reported outcomes (PROs) were assessed; utility (EQ5D), PCS and MCS (Physical and Mental Health Component Summaries) scores of the SF-36, fatigue (FIS-total score). Also, Emergency Medical Facility Visits (EMFV; a visit to a medical facility/hospital for emergency care not resulting in an admission) was tracked. Changes from Baseline for PROs and annual EMFV rate were analysed for a two-year period. RESULTS: Change from baseline (CfB) in utility in patients with no relapse was +0.034, CfB in utility in patients with relapse(s) not leading to hospitalisation was -0.019(*p1<0.01) and CfB in utility in patients with relapse(s) leading to hospitalisation was -0.057(p1<0.001; p2:ns). Similar results were seen for PCS of +1.0, -1.0 (p1<0.01) and -3.1(p1<0.001; p2<0.05) respectively and for MCS were respectively +1.8, -1.0(p1<0.01) and -2.7 (p1<0.001; p2:ns). This same trend was observed with FIS total score, (CfB was respectively: -3.0, +1.4 (p1:ns) and +10.3 (p1<0.001; p2<0.01). The mean annual EMFV rate in patients with no relapse was 0.5 and in patients with relapse not leading to hospitalisation was 0.4 (p1:ns). This rate was increased to 1.2 (p1<0.05; p2<0.001) in patients with relapse leading to hospitalisation. CONCLUSIONS: In TEMSO, patients with relapse leading to hospitalisation comparatively have worsening in HR-QoL (EQ-5D, SF-36), fatigue and have a higher number of EMFV. *p1: versus patients with no relapse, p2: versus patients with relapse not leading to hospitalisation