Objective: People with Multiple Sclerosis (MS) experience lower levels of quality of life (QOL) than people from the general population. We examined the relative impact of MS-related disabilities on QOL.
Method: Data were obtained from a sample of 530 patients who completed the Multiple Sclerosis Impact Profile (MSIP), a disability measure based on the International Classification of Functioning, Disabilities and Health (ICF) and two generic health-related QOL measures, the Medical Outcome study Short Form Questionnaire (SF-36) and the World Health Organization Quality Of Life-BREF (WHOQOL-BREF). The impact of disabilities on QOL was estimated using hierarchical multiple regression analyses after controlling for the clinical course of MS.
Results: Disabilities contributed to a unique and substantial extent to QOL variance. "Impairments in mental functions" was the most important QOL predictor. "Fatigue" showed the highest prevalence and severity scores, while the impact on QOL was limited. The estimated impact on QOL appeared to be dependent on the applied QOL measure: the WHOQOL-BREF was sensitive to disabilities related to all four ICF components, while the SF-36 was only sensitive to disabilities belonging to the 'body functions' and 'activities' components.
Conclusion: Treatment programmes should target impairments in cognitive functioning, emotional functioning and sleep. Interventions are best evaluated using the WHOQOL-BREF.