Physical and psychological burden in RRMS: depression and fatigue beyond disease duration

Multiple sclerosis (MS) is a chronic, autoimmune, demyelinating and neurodegenerative disease. Accumulation of physical and psychological disabilities adversely affects patients' health-related quality of life. The 29-item Multiple Sclerosis Impact Scale (MSIS-29) is a self-reported measure of the physical and psychological burden. To evaluate the physical and psychological impact levels in patients with MS and to examine their relationship with disease duration. We enrolled 100 consecutive adults aged 18 to 55 years with relapsing-remitting MS (RRMS). The Expanded Disability Status Scale (EDSS), annual relapse rate (ARR), Beck Depression Inventory (BDI), Fatigue Severity Scale (FSS), MSIS-29, and Timed 25-Foot Walk Test (25-FWT) were applied. A total of 57 participants (57%) were female patients. The mean age was 38.5 ± 8.0 years, and the mean disease duration, 9.8 ± 6.8 years. The mean MSIS-29 physical and psychological scores were 36.7 ± 15.7 and 45.3 ± 20.4 respectively. No significant differences were found between patients with disease duration ≤ 10 and > 10 years in terms of the physical (p = 0.263) or psychological (p = 0.551) subscales. Physical impact was significantly associated with the female sex (p = 0.021) and the scpres on the EDSS (p = 0.030), BDI (p < 0.001), and FSS (p < 0.001). Psychological impact showed significant associations with the female sex (p = 0.005), ARR (p = 0.020), and the scores on the BDI (p < 0.001), and FSS (p < 0.001). On multivariate regression, the scores on the EDSS, BDI, and 25-FWT were independent predictors of physical impact, while the female sex and the scores on the EDSS and BDI were independent predictors of psychological impact. Disease duration did not predict physical or psychological impact in RRMS. Depression severity, lower-extremity function, and the female sex were the independent determinants of disease-related impact in the multivariate analysis. The association of fatigue with disease impact, significant at the bivariate level, was attenuated by depression in the multivariate analysis. Routine assessment of these modifiable factors should be accompanied by disease-modifying treatments in MS care.