Is there a differential impact of fatigue and physical disability on quality of life in multiple sclerosis?

To investigate the quantitative impact of fatigue on health-related quality of life (HRQoL) in multiple sclerosis (MS) and to determine whether fatigue was related to HRQoL independently from bodily disability, data on HRQoL were ascertained for 87 patients with definite MS by using the SF-36. HRQoL scores and subscores were related to the basic MS disability score (EDSS) and further MS parameters, and to fatigue, which was assessed by using different fatigue scales. Factors related to predominantly physical but not mental HRQoL aspects were identified as related to EDSS, duration of disease, and age. Different fatigue scores did impact significantly on both physical and especially mental HRQoL. The influence of fatigue on physical HRQoL was independent from EDSS. Fatigue experience reduces HRQoL markedly and independently from EDSS. Therefore, fatigue assessment provides additional information to disability-derived scales such as the EDSS with relevant implications for therapeutic decisions.