A real-world study characterizing symptoms and impacts of fatigue in US adults with relapsing multiple sclerosis using a novel disease specific scale

Background: Fatigue is among the most frequent and disabling symptoms in patients with relapsing multiple sclerosis (RMS). Objective: To measure MS fatigue and its impact on daily life in a real-world US population using an MS-specific patient-reported outcome (PRO) instrument, the Fatigue Symptoms and Impacts Questionnaire-RMS (FSIQRMS). Methods: This ongoing prospective study recruited RMS patients from an online patient community (Carenity) across US. Baseline assessment data are reported. Participants completed questionnaires, including the 20-item FSIQ-RMS questionnaire, with the first seven symptom-related items collected daily for seven days, and the other 13 items on the seventh day assessing impacts of fatigue. The FSIQ-RMS scores range from 0 to 100 (higher score=greater severity). The impact of fatigue on several aspects of patients' lives was rated from 0 (no impact) to 10 (very high impact). Data on disease history, disease status, sleep, social and emotional functioning were also captured. Baseline assessment data of 300 RMS patients are reported while follow-up assessments up to 18 months are planned. Results: 300 RMS participants completed the 7-day assessment (mean age 43.0 years, 88% women). Fatigue was rated as severe, with a mean score of 57.3 for the FSIQ-RMS symptom domain; 3 impact sub-domain scores were 42.3, 43.4 and 50.1 (physical, cognitive/emotional, and coping). Participants who were not in relapse (78%) reported less severe fatigue than those in relapse (22%): mea +/- SD symptom score of 54.6 +/- 17.8 vs. 67.0 +/- 19.7, p < 0.001. Fatigue had a higher intensity among those with depression than without (49% vs. 51%, with mean +/- SD symptom score of 62.8 +/- 16.9 vs. 52.1 +/- 19.3, p < 0.001), and among those with sleep disorder than without (27% vs. 73%, 61.2 +/- 19.2 vs. 55.9 +/- 18.6; p < 0.05). The most common factor associated with increased fatigue was heat exposure (82%). Most participants (52%) reported experiencing fatigue before their MS diagnosis. Conclusion: Fatigue influences daily functioning for most patients with RMS. The FSIQ-RMS is a novel and MS specific PRO measure that can advance the understanding and management of fatigue.