Disability in people with multiple sclerosis with focus on fatigue

Abstract

Background: Knowledge of the concurrent presence of disabilities and of their association with the perceived physical and psychological impact of MS on health in people with MS is sparse. Fatigue is commonly reported and may cause limitations in daily life. Little is known regarding how fatigue varies over time and regarding which factors contribute to variations in fatigue. Dimensions of MS-related fatigue that can be modified by interventions need to be identified. Health services may alleviate the difficulties of living with a health condition, but the manner in which the presence or absence of fatigue is associated with the use of health services has not been explored.

Aim: To explore disabilities in people with MS and their association with the perceived physical and psychological impact on health; variations in fatigue and the capacity of selected factors to predict fatigue; the applicability of the Swedish Occupational Fatigue Inventory; and the use of health services in people with and without fatigue.

Methods: People with MS, outpatients at a specialist clinic were assessed every six months over the course of two years with tests and questionnaires, in order to collect data on disabilities (fatigue, depressive symptoms, cognitive impairment, limitation in walking and in fine hand use, limitation in activities of daily living, and restriction in social/lifestyle activities), contextual factors, disease-related variables, perceived physical and psychological impact of MS on health, and use of health services.

Results: Of the 219 people with MS included, 59% had mild MS. Two or more of the seven disabilities studied were found in 81%; 24% had six or seven disabilities. Fatigue and depressive symptoms were associated with both high perceived physical and high perceived psychological impact. During two years, 54% changed category of severity of fatigue and 27% had persistent fatigue. Depressive symptoms, weak/moderate sense of coherence, living with a partner and not working were independent predictors of increase in fatigue; people with moderate MS appeared at particular risk. The Swedish Occupational Fatigue Inventory appeared partly applicable for use in people with MS; it discriminated among dimensions and seemed to measure fatigue within a different construct than other frequently used scales. People with mild MS and fatigue used more outpatient health-care than people with mild MS without fatigue; few such differences were found in people with moderate/severe MS. Regardless of MS severity, higher proportions of people with fatigue than people without fatigue received informal care.

Conclusions: The high concurrent presence of disabilities in people with MS highlights the importance of systematic assessment of level of functioning in all states of the disease. In light of the variation of fatigue and the impact of depressive symptoms and contextual factors on fatigue, health services targeting people with MS should not only monitor disease-related variables but also apply a broad range of approaches to assess fatigue and provide appropriate interventions. The Swedish Occupational Fatigue Inventory might be a useful addition for the assessment of fatigue in MS, but development of the physical dimensions and the psychometric properties is needed. The generally higher use of health care in people with mild MS with fatigue suggests that a multi-professional team is best suited to provide services, even in the early phases of the disease. Health services should take the situation of partners and significant others into thorough consideration, regardless of MS severity, if fatigue is present. Authorities making decisions regarding the provision of salaried services in people with MS should always carefully consider the presence of fatigue.