Worldwide Longitudinal Observational Study of Fatigue-Related Symptoms in Patients With Relapsing Multiple Sclerosis, Daily Assessment and 7-Day Lookback

OBJECTIVES: According to the WHO (World Health Organization), more than 1.8 million individuals are affected by multiple sclerosis, a chronic disease where fatigue is one of the most common and incapacitating symptoms. An observational longitudinal international study was conducted to evaluate fatigue-related symptoms and their impacts on Relapsing Multiple Sclerosis (RMS) patients‘ life. This real-world study included the validated Patient Reported Outcome (PRO) FSIQ-RMS (Fatigue Symptoms and Impacts Questionnaire – RMS). The answers of the FSIQ-RMS regarding daily fatigue were analyzed and compared to a 7-day retrospective assessment.

METHODS: The FSIQ-RMS was administered through an online survey. A total of 362 MS patients in Europe, 300 in US and 60 in Latin America (Colombia and Mexico) were enrolled. Every day for 7 days, participants were asked to report their fatigue-related symptoms, and on the seventh day, they were asked to assess their fatigue over the previous 7 days. FSIQ-RMS and 7-day lookback scores were compared using Pearson's correlation coefficient (r) for all regions at baseline, and for the US after 6, 12 and 18 months.

RESULTS: Mean FSIQ-RMS symptom scores at baseline were 55.2 in Europe, 57.3 in the US and 67.8 in LATAM, and 7-day look-back scores were 57.0, 58.7 and 69.8 respectively. For all regions, correlation between FSIQ-RMS and 7-day lookback was 0.93. In the US, FSIQ-RMS symptom scores and 7-day lookback scores were respectively 58.0 and 60.5 after 6 months, 56.4 and 57.0 after 12 months, and 57.6 and 60.0 after 18 months with r-ranges between [0.89-0.94]. All r’s were close to one, indicating a strong correlation between the two scores.

CONCLUSIONS: Given the high similarity between the FSIQ-RMS daily symptom score and its 7-day retrospective assessment in different regions and at different points in the analysis, the results suggest that the 7-day lookback assessment is reliable.