title: A population-based study comparing multiple sclerosis clinic users and non-users in British Columbia, Canada.
abstract: Much clinical knowledge about multiple sclerosis (MS) has been gained from patients who attend MS specialty clinics. However, there is limited information about whether these patients are representative of the wider MS population. The objective of this study was to compare incident MS cases who were MS clinic users to non-users of the specialty MS clinics in British Columbia, Canada.
  
  
  
  This was a retrospective record-linkage cohort study using prospectively collected data from the British Columbia Multiple Sclerosis database and province-wide health administrative databases.
  
  
  
  There were 2841 incident MS cases between 1996 and 2004 including 1648 (58%) that had registered at an MS clinic ('clinic cases') and 1193 (42%) that had not ('non-clinic cases'). Gender and socioeconomic status distributions were similar; however, non-clinic cases were older, accessed health services more frequently and had a higher burden of comorbidity than clinic cases. Only 1% of the non-clinic cases had filled a prescription for an MS-specific disease-modifying therapy, compared to 51% of the clinic cases.
  
  
  
  Our findings have several important implications: even within a publicly funded healthcare system, a high proportion of individuals with MS may not access a specialty MS clinic; the needs of MS patients managed in the community may differ from those referred to an MS clinic; findings from studies involving clinic-based MS cohorts may not always be generalizable to the wider MS population; and access to population-based health administrative data offers the opportunity to gain a broader understanding of MS.
authors.affiliation: Department of Neurology, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: K A
authors.identifier: 0000-0002-9081-1522
authors.initials: KA
authors.lastname: McKay
authors.affiliation: Department of Neurology, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Tremlett
authors.affiliation: Department of Neurology, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Zhu
authors.affiliation: Department of Neurology, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Kastrukoff
authors.affiliation: Department of Community Health Sciences, College of Medicine, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: R A
authors.initials: RA
authors.lastname: Marrie
authors.affiliation: Department of Neurology, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Kingwell
mesh_terms: D000328:Adult; D001955:British Columbia / Q000453:epidemiology; D015897:Comorbidity; D016208:Databases, Factual; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology*; D010044:Outpatient Clinics, Hospital / Q000706:statistics & numerical data*
keywords: clinical research; databases; epidemiology; health services; multiple sclerosis