title: A novel method for calculating prevalence of multiple sclerosis in Australia.
abstract: OBJECTIVE
  The purpose of this study was to determine the prevalence of multiple sclerosis (MS) in Australia in 2010 using a novel method based on Australia-wide prescription data for MS-specific disease modifying agents. The results obtained were validated against two other prevalence estimates.
  
  
  METHODS
  We obtained the total number of scripts for medications that were used exclusively for the treatment of MS written in Australia for the period January-December 2010. The percentage of MS patients using medications (42-55%) was taken from state-specific surveys of MS Society clients. To estimate prevalence we divided the annual number of scripts dispensed by 12 and adjusted for penetration of medications by state.
  
  
  RESULTS
  The prevalence of MS in Australia in 2010 calculated using the prescription method was 21,283 people (95.5/100,000). This compared to 21,200 people (95.2/100,000) obtained from the Australian Bureau of Statistics (ABS) Survey of Disability, Ageing and Carers (SDAC) survey of 2009 and 20,471 people (91.9/100,000) using MS Society client numbers. Prevalence increased with increasing latitude, with the prevalence for Tasmania over seven times that of the Northern Territory. Results were sensitive to the percentage of people with MS being treated.
  
  
  CONCLUSIONS
  Calculation of prevalence of MS using nation-wide prescription data is a novel method that generates results similar to other potentially more resource-intensive methods.
authors.affiliation: Menzies Research Institute Tasmania, Australia.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Palmer
authors.forename: Peta L
authors.initials: PL
authors.lastname: Hitchens
authors.forename: Steve
authors.initials: S
authors.lastname: Simpson
authors.forename: Beth
authors.initials: B
authors.lastname: O'Leary
authors.forename: Sam
authors.initials: S
authors.lastname: Colman
authors.forename: Bruce V
authors.initials: BV
authors.lastname: Taylor
mesh_terms: D000367:Age Factors; D001315:Australia / Q000453:epidemiology; D004185:Disability Evaluation; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D004812:Epidemiologic Methods; D005843:Geography; D006801:Humans; D007356:Insurance, Pharmaceutical Services / Q000191:economics / Q000706:statistics & numerical data; D009103:Multiple Sclerosis / Q000453:epidemiology*; D009313:National Health Programs; D015995:Prevalence; D012424:Rural Population; D013648:Tasmania / Q000453:epidemiology; D014505:Urban Population
keywords: Multiple sclerosis; disease modifying therapies; prevalence