Mortality and cause of death in multiple sclerosis: findings from a prospective population-based cohort in Bizkaia, Basque Country, Spain

Abstract

Background: Mortality studies of multiple sclerosis (MS) patients are scarce.

Objective: To assess mortality of MS patients included in a large MS cohort from the county of Bizkaia in Spain.

Methods: Patients were collected from a dynamic population-based cohort of patients with MS from the county of Bizkaia (named the 'Bizkaia cohort') in the Basque Country (Spain). Data from official registries were used for estimating mortality indicators.

Results: During a 24-year period (1987-2011), a total of 1,283 patients were included in the Bizkaia cohort. Eighty-nine patients (6.9%) had died before December 31, 2011. The standardized mortality ratio was 2.78 for the whole group (3.26 for men and 2.73 for women), with a decreased life expectancy of 6.53 years. The mean survival from the onset of MS in deceased patients was 22.4 years. Death was related directly or indirectly to MS in 57 patients and unrelated in 27, while the cause of death was unknown in the remaining 5. Respiratory infection and sepsis were the most frequent MS-related causes of death. Differences in survival according to gender or disease course were not observed.

Conclusion: Patients with MS included in the 'Bizkaia cohort' had an almost threefold increase in the risk for death. Life expectancy is reduced by 6-10 years.