title: Trajectory of MS disease course for men and women over three eras.
abstract: BACKGROUND
  Heterogeneity in disease course exists within multiple sclerosis (MS) subtypes.
  
  
  OBJECTIVE
  The objective was to estimate disease course heterogeneity over three distinct onset periods (pre-1995, 1995-2004, and 2005-present) for men and women.
  
  
  METHODS
  Group-based trajectory model (GBTM) was used to estimate clusters of patients following stable or unstable disease progression trajectories based on the Expanded Disability Status Scale (EDSS). Inception cohorts were generated from the Montreal Neurological Institute MS Clinic registry. Stable trajectories were defined as an EDSS ⩽3.0 and change ⩽1 point over the study period. Annualized relapse rate (ARR) based on the first 5 years of disease was an explanatory variable.
  
  
  RESULTS
  Proportion of women classified as stable was 0% for pre-1995, 69.0% for 1995-2004, and 83.9% post-2005; for men, these proportions were 18.4%, 41.4%, and 53.8%, respectively. Men had lower percentage of stable disease than women in both post-1995 cohorts (chi-square p < 0.0001). ARR was associated with higher disability trajectories in both post-1995 cohort (odds ratios >1.0) but not in the pre-1995 cohort.
  
  
  CONCLUSIONS
  Large proportions of patients remain stable at their initial disability level for at least 15 years. Higher ARR increases the odds of patients being in a higher disability trajectory in the latter cohorts.
authors.affiliation: Montreal Neurological Institute and Hospital, McGill University Health Center, Montreal, QC, Canada.
authors.forename: Stanley
authors.initials: S
authors.lastname: Hum
authors.affiliation: Montreal Neurological Institute and Hospital, McGill University Health Center, Montreal, QC, Canada.
authors.forename: Yves
authors.initials: Y
authors.lastname: Lapierre
authors.affiliation: Division of Clinical Epidemiology, McGill University Health Center, Montreal, QC, Canada.
authors.forename: Susan C
authors.initials: SC
authors.lastname: Scott
authors.affiliation: Neurologie, Centre hospitalier de l'Université de Montréal, Montréal, QC, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Duquette
authors.affiliation: School of Physical and Occupational Therapy, Faculty of Medicine, McGill University, Montreal, QC, Canada/Division of Clinical Epidemiology, McGill University Health Center, Montreal, QC, Canada.
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Mayo
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D009103:Multiple Sclerosis / Q000145:classification / Q000175:diagnosis / Q000628:therapy; D012008:Recurrence; D012720:Severity of Illness Index
keywords: Multiple sclerosis; disease course; epidemiology