Prevalence and severity of multiple-sclerosis-associated fatigue in treated and untreated patients

Fatigue is one of the most frequent and most disabling symptoms in multiple sclerosis (MS). We investigated the possible association of the MS-related fatigue syndrome with the available disease-modifying therapies and the main disease characteristics in a cross-sectional study on 320 consecutive patients. The prevalence of severe fatigue (Fatigue Severity Scale score > or =5) was 50%. In a multivariate regression model controlling for age, disease subtype, duration and disability we did not find a significant association between the use of immunosuppressive or immunomodulatory drugs compared to no treatment (OR = 1.34, p = 0.38 for immunosuppressants; OR = 0.95, p = 0.85 for immune-modulating agents). Although all used disease-modifying agents successfully reduce disease activity and inflammation, they do not appear to exhibit a significant effect on MS-related fatigue.