The Fatigue Symptoms and Impacts Questionnaire – Relapsing Multiple Sclerosis (FSIQ-RMS) is a new content-valid, concise, reliable 20-item patient-reported outcome (PRO) measure to evaluate the symptoms and impacts of fatigue in patients with relapsing forms of multiple sclerosis (MS). Analyses were performed to derive meaningful change thresholds (MCTs) on PROs as measured by FSIQ-RMS and generate receiver operating characteristic (ROC) curves to determine fatigue severity cut points at baseline and change in severity at post-baseline, and supplement the anchor-based MCT results.
Analyses were based on data from the OPTIMUM trial (NCT02425644). An anchor-based approach using uncollapsed changes on the PGI-S at Week 108 were used to determine the MCT for only the FSIQ RMS-S; distribution based MCT estimations were conducted using baseline FSIQ RMS-I scores. ROC curves with calculation of area under the curve were used to identify the best cut point.
Based on the evidence provided by the anchor-based analyses using the Patient Global Impression of Severity (PGI-S) as an anchor for the FSIQ-RMS Symptoms domain, meaningful score changes for improvement and deterioration were -6.3 and 6.3, respectively. Meaningful score changes for the FSIQ-RMS Physical, Cognitive/Emotional, and Coping Impacts domains using distribution-based methods were 10.8, 8.4, and 9.8, respectively. These results are supported by the ROC analyses.
Thresholds to support interpretation of the FSIQ-RMS, such as MCTs, can be used to determine and categorize patients who have experienced a meaningful change in their MS-related fatigue (e.g., responder analyses) in future clinical research studies.

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