title: Demographic and clinical features of inclusion body myositis in North America.
abstract: BACKGROUND
  Few studies of the demographics, natural history, and clinical management of inclusion body myositis (IBM) have been performed in a large patient population. To more accurately define these characteristics, we developed and distributed a questionnaire to patients with IBM.
  
  
  METHODS
  A cross-sectional, self-reporting survey was conducted.
  
  
  RESULTS
  The mean age of the 916 participants was 70.4 years, the male-to-female ratio was 2:1, and the majority reported difficulty with ambulation and activities of daily living. The earliest symptoms included impaired use and weakness of arms and legs. The mean time from first symptoms to diagnosis was 4.7 years. Half reported that IBM was their initial diagnosis. A composite functional index negatively associated with age and disease duration, and positively associated with participation in exercise.
  
  
  CONCLUSIONS
  These data are valuable for informing patients how IBM manifestations are expected to impair daily living and indicate that self-reporting could be used to establish outcome measures in clinical trials.
authors.affiliation: Yale School of Public Health, New Haven, Connecticut, USA.|Yale School of Management, New Haven, Connecticut, USA.
authors.forename: A David
authors.initials: AD
authors.lastname: Paltiel
authors.affiliation: Yale School of Management, New Haven, Connecticut, USA.
authors.forename: Einar
authors.initials: E
authors.lastname: Ingvarsson
authors.affiliation: Yale School of Management, New Haven, Connecticut, USA.
authors.forename: Donald K K
authors.initials: DK
authors.lastname: Lee
authors.affiliation: Richard L. Leff, MD, LLC, Chadds Ford, Pennsylvania, USA.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Leff
authors.affiliation: Department of Neurology, Yale School of Medicine, 300 George Street, Room 353J, New Haven, Connecticut, USA, 06511.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Nowak
authors.affiliation: Yale School of Public Health, New Haven, Connecticut, USA.
authors.forename: Kurt D
authors.initials: KD
authors.lastname: Petschke
authors.affiliation: H. John Heinz III College, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.
authors.forename: Seth
authors.initials: S
authors.lastname: Richards-Shubik
authors.affiliation: Yale School of Management, New Haven, Connecticut, USA.
authors.forename: Ange
authors.initials: A
authors.lastname: Zhou
authors.affiliation: Yale School of Management, New Haven, Connecticut, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Shubik
authors.affiliation: Department of Neurology, Yale School of Medicine, 300 George Street, Room 353J, New Haven, Connecticut, USA, 06511.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: O'Connor
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D003710:Demography; D006233:Persons with Disabilities; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018979:Myositis, Inclusion Body / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology*; D009656:North America / Q000453:epidemiology; D057566:Self Report
keywords: demographics; inclusion body myositis; myopathy; natural history; survey