Longitudinal effects of dimethyl fumarate on patient-reported outcome measures in multiple sclerosis: treatment satisfaction, quality of life, depressive symptoms, sleep, and work productivity

BACKGROUND: Oral therapies for relapsing-remitting multiple sclerosis (RRMS) may enhance treatment satisfaction and quality of life. Patient-reported outcome measures (PROMs) provide structured insight into treatment effectiveness and disease impact beyond clinician-reported scales. OBJECTIVE: To assess treatment satisfaction and other PROMs in RRMS patients initiating dimethyl fumarate (DMF), either treatment-naïve or switching from injectable therapies. METHODS: PROFIT was a 12-month, multicenter, phase 4, open-label, single-arm observational study conducted in Iran. Patients received DMF with a slow-dose titration regimen to mitigate gastrointestinal adverse effects. The primary endpoint was the change in treatment satisfaction, assessed by the Treatment Satisfaction Questionnaire for Medication (TSQM-14), from baseline to month 12 among previously treated patients. Key secondary endpoints included changes in additional PROMs, including health-related quality of life (HRQoL), depressive symptoms, sleep quality, and work productivity. Patient-reported outcomes were assessed using the EuroQol-5D-3L (EQ-5D-3L), Beck Depression Inventory-Fast Screen (BDI-7), Pittsburgh Sleep Quality Index (PSQI), and Work Productivity and Activity Impairment-Multiple Sclerosis (WPAI-MS) at baseline, 6 months, and 12 months. Adverse events were monitored monthly, with safety evaluated as a secondary outcome. RESULTS: Of 645 patients (72.3 % female; mean age 34.0 years), 473 (73.3 %) completed the 12-month follow-up, while 172 (26.7 %) discontinued treatment. The primary endpoint, change in treatment satisfaction (TSQM-14) among previously treated patients, showed significant improvement across all domains: effectiveness (+13.01), side effects (+7.76), convenience (+35.21), and global satisfaction (+15.75) (all p < 0.001). Secondary endpoints also demonstrated favorable changes, including EQ-5D-3L utility (+0.07), EQ-5D Visual Analogue Scale (VAS) (+3.86), PSQI (-1.62), WPAI absenteeism (-7.55 %), and BDI-7 (-0.11) (all p < 0.001). Treatment discontinuations (26.7 %) were primarily due to gastrointestinal adverse events (n = 45, 26.0 %), followed by physician decision (n = 34, 20.0 %), disease progression (n = 26, 15.0 %), patient preference (n = 19, 11.0 %), pregnancy (n = 14, 8.0 %), elevated liver enzymes (n = 13, 7.0 %), and other causes (n = 21, 12.0 %). Adverse events declined over time, confirming a favorable and manageable safety profile. CONCLUSION: DMF was associated with improvements in treatment satisfaction, quality of life, sleep quality, work productivity, and depressive symptoms in both treatment-naïve and previously treated RRMS patients, with high adherence and manageable side effects. These findings provide real-world evidence from an Iranian RRMS cohort, supporting DMF as a well-tolerated, patient-centered option with multidimensional benefits observed under routine clinical conditions.