A contemporary study of mortality in the multiple sclerosis population of south east Wales.

Background: Mortality studies in multiple sclerosis (MS) are valuable to identify changing disease patterns and inform clinical management. This study examines mortality in a British MS cohort.

Methods: Patients were selected from the southeast Wales MS registry. Hazard of death was analysed using Cox proportional hazards regression, adjusted for onset age, annualised relapse rate, initial disease course, time to EDSS 4.0, sex, socioeconomic status, and onset year. Age- and sex-stratified standardised mortality ratios (SMRs) were calculated by EDSS scores.

Results: Median time from MS diagnosis to death was 35.5 years and median age 73.9. Older onset age (hazard ratio [HR] 1.05, 95% confidence interval 1.03-1.06) was associated with increased hazard of death. Primary progressive course was associated with increased hazard of death in women (HR 2.04, 1.15-3.63) but not men (HR 1.23, 0.61-2.47). Slow time to EDSS 4.0 (HR 0.41, 0.28-0.60) and high socioeconomic status (HR 0.54, 0.37-0.79) were associated with reduced hazard of death. SMR increased from EDSS 6.0 (3.86, 2.63-5.47) but more substantially at EDSS 8.0 (22.17, 18.20-26.75).

Conclusions: Risk of death in MS varies substantially with degree of disability. This has important implications for clinical management and health economic modelling.