title: Effect of comorbidity on mortality in multiple sclerosis.
abstract: OBJECTIVE
  We aimed to compare survival in the multiple sclerosis (MS) population with a matched cohort from the general population, and to evaluate the association of comorbidity with survival in both populations.
  
  
  METHODS
  Using population-based administrative data, we identified 5,797 persons with MS and 28,807 controls matched on sex, year of birth, and region. We estimated annual mortality rates. Using Cox proportional hazards regression, we evaluated the association between comorbidity status and mortality, stratifying by birth cohort, and adjusting for sex, socioeconomic status, and region. We compared causes of death between populations.
  
  
  RESULTS
  Median survival from birth in the MS population was 75.9 years vs 83.4 years in the matched population. MS was associated with a 2-fold increased risk of death (adjusted hazard ratio 2.40; 95% confidence interval: 2.24-2.58). Several comorbidities were associated with increased hazard of death in both populations, including diabetes, ischemic heart disease, depression, anxiety, and chronic lung disease. The magnitude of the associations of mortality with chronic lung disease, diabetes, hypertension, and ischemic heart disease was lower in the MS population than the matched population. The most common causes of death in the MS population were diseases of the nervous system and diseases of the circulatory system. Mortality rates due to infectious diseases and diseases of the respiratory system were higher in the MS population.
  
  
  CONCLUSIONS
  In the MS population, survival remained shorter than expected. Within the MS population, comorbidity was associated with increased mortality risk. However, comorbidity did not preferentially increase mortality risk in the MS population as compared with controls.
authors.affiliation: From the Departments of Internal Medicine (R.A.M., J.M., M.C.) and Community Health Sciences (R.A.M., L.E., J.B., S.L., N.Y.), University of Manitoba, Winnipeg; Epidemiology and Surveillance (N.Y.), Public Health and Primary Care Division, Manitoba Health, Winnipeg, Canada. rmarrie@hsc.mb.ca.
authors.forename: Ruth Ann
authors.initials: RA
authors.lastname: Marrie
authors.affiliation: From the Departments of Internal Medicine (R.A.M., J.M., M.C.) and Community Health Sciences (R.A.M., L.E., J.B., S.L., N.Y.), University of Manitoba, Winnipeg; Epidemiology and Surveillance (N.Y.), Public Health and Primary Care Division, Manitoba Health, Winnipeg, Canada.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Elliott
authors.affiliation: From the Departments of Internal Medicine (R.A.M., J.M., M.C.) and Community Health Sciences (R.A.M., L.E., J.B., S.L., N.Y.), University of Manitoba, Winnipeg; Epidemiology and Surveillance (N.Y.), Public Health and Primary Care Division, Manitoba Health, Winnipeg, Canada.
authors.forename: James
authors.initials: J
authors.lastname: Marriott
authors.affiliation: From the Departments of Internal Medicine (R.A.M., J.M., M.C.) and Community Health Sciences (R.A.M., L.E., J.B., S.L., N.Y.), University of Manitoba, Winnipeg; Epidemiology and Surveillance (N.Y.), Public Health and Primary Care Division, Manitoba Health, Winnipeg, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Cossoy
authors.affiliation: From the Departments of Internal Medicine (R.A.M., J.M., M.C.) and Community Health Sciences (R.A.M., L.E., J.B., S.L., N.Y.), University of Manitoba, Winnipeg; Epidemiology and Surveillance (N.Y.), Public Health and Primary Care Division, Manitoba Health, Winnipeg, Canada.
authors.forename: James
authors.initials: J
authors.lastname: Blanchard
authors.affiliation: From the Departments of Internal Medicine (R.A.M., J.M., M.C.) and Community Health Sciences (R.A.M., L.E., J.B., S.L., N.Y.), University of Manitoba, Winnipeg; Epidemiology and Surveillance (N.Y.), Public Health and Primary Care Division, Manitoba Health, Winnipeg, Canada.
authors.forename: Stella
authors.initials: S
authors.lastname: Leung
authors.affiliation: From the Departments of Internal Medicine (R.A.M., J.M., M.C.) and Community Health Sciences (R.A.M., L.E., J.B., S.L., N.Y.), University of Manitoba, Winnipeg; Epidemiology and Surveillance (N.Y.), Public Health and Primary Care Division, Manitoba Health, Winnipeg, Canada.
authors.forename: Nancy
authors.initials: N
authors.lastname: Yu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008350:Manitoba / Q000453:epidemiology; D008875:Middle Aged; D009026:Mortality / Q000639:trends; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000401:mortality*; D011159:Population Surveillance / Q000379:methods