title: Relative mortality and survival in multiple sclerosis: findings from British Columbia, Canada.
abstract: OBJECTIVE
  To examine mortality and factors associated with survival in a population based multiple sclerosis (MS) cohort.
  
  
  METHODS
  Clinical and demographic data of MS patients registered with the British Columbia MS clinics (1980-2004) were linked to provincial death data, and patients were followed until death, emigration or study end (31 December 2007). Absolute survival and the influence of patient characteristics (sex, disease course (primary progressive (PPMS) vs relapsing onset (R-MS)) and onset age) were estimated by Kaplan-Meier analyses (from birth and disease onset). Mortality relative to the general population was examined using standardised mortality ratios. Excess mortality associated with patient characteristics and time period of cohort entry was assessed by relative survival modelling.
  
  
  RESULTS
  Of 6917 patients, 1025 died. Median survival age was 78.6 years (95% CI 77.5 to 79.7) for women and 74.3 years (95% CI 73.1 to 75.4) for men. Survival from onset was longer for R-MS (49.7 years; 95% CI 47.9 to 51.5) than for PPMS (32.5 years; 95% CI 29.5 to 35.7); however, survival age was similar. The overall standardised mortality ratios was 2.89 (95% CI 2.71 to 3.07), and patients survived approximately 6 years less than expected, relative to the general population. PPMS had a higher relative mortality risk compared with R-MS (relative mortality ratio (RMR) 1.52; 95% CI 1.30 to 1.80). Women with PPMS had a relative survival disadvantage compared with men with PPMS (RMR 1.55; 95% CI 1.19 to 2.01). Relative survival within 10 years of cohort entry was similar between time periods.
  
  
  CONCLUSIONS
  Some of the longest MS survival times are reported here but the risk of death was still greater than in the age, sex and calendar year matched general population. No evidence of increased survival over time was found when improved survival in the general population was taken into consideration.
authors.affiliation: Faculty of Medicine, Division of Neurology, University of British Columbia, Vancouver, British Columbia, Canada. elainejk@mail.ubc.ca
authors.forename: E
authors.initials: E
authors.lastname: Kingwell
authors.forename: M
authors.initials: M
authors.lastname: van der Kop
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.forename: A
authors.initials: A
authors.lastname: Shirani
authors.forename: F
authors.initials: F
authors.lastname: Zhu
authors.forename: J
authors.initials: J
authors.lastname: Oger
authors.forename: H
authors.initials: H
authors.lastname: Tremlett
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D001955:British Columbia / Q000453:epidemiology; D018450:Disease Progression; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000401:mortality*; D020528:Multiple Sclerosis, Chronic Progressive / Q000401:mortality; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000401:mortality; D016016:Proportional Hazards Models; D012737:Sex Factors; D016019:Survival Analysis; D055815:Young Adult