Costs and quality of life by disability among people with multiple sclerosis : a register-based study in Sweden

Background: Population-based estimates of costs of illness and health-related quality of life, by disability levels among people with multiple sclerosis, are lacking. Objectives: To estimate the annual costs of illness and health-related quality of life, by disability levels, among multiple sclerosis patients, 21-64 years of age. Methods: Microdata from Swedish nationwide registers were linked to estimate the prevalence-based costs of illness in 2013, including direct costs (prescription drug use and specialised healthcare) and indirect costs (calculated using sick leave and disability pension), and health-related quality of life (estimated from the EQ-5D). Disability level was measured by the Expanded Disability Status Scale (EDSS). Results: Among 8906 multiple sclerosis patients, EDSS 0.0-3.5 and 7.0-9.5 were associated with mean indirect costs of SEK 117,609 and 461,357, respectively, whereas direct costs were similar between the categories (SEK 117,423 and 102,714, respectively). Prescription drug costs represented 40% of the costs of illness among multiple sclerosis patients with low EDSS, while among patients with high EDSS more than 80% were indirect costs. Among the 1684 individuals who had reported both EQ-5D and EDSS, the lowest health-related quality of life scores were found among those with a high EDSS. Conclusion: Among people with multiple sclerosis, we confirmed higher costs and lower health-related quality of life in higher disability levels, in particular high indirect costs.