title: Systemic autoimmune rheumatic disease prevalence in Canada: updated analyses across 7 provinces.
abstract: OBJECTIVE
  To estimate systemic autoimmune rheumatic disease (SARD) prevalence across 7 Canadian provinces using population-based administrative data evaluating both regional variations and the effects of age and sex.
  
  
  METHODS
  Using provincial physician billing and hospitalization data, cases of SARD (systemic lupus erythematosus, scleroderma, primary Sjögren syndrome, polymyositis/dermatomyositis) were ascertained. Three case definitions (rheumatology billing, 2-code physician billing, and hospital diagnosis) were combined to derive a SARD prevalence estimate for each province, categorized by age, sex, and rural/urban status. A hierarchical Bayesian latent class regression model was fit to account for the imperfect sensitivity and specificity of each case definition. The model also provided sensitivity estimates of different case definition approaches.
  
  
  RESULTS
  Prevalence estimates for overall SARD ranged between 2 and 5 cases per 1000 residents across provinces. Similar demographic trends were evident across provinces, with greater prevalence in women and in persons over 45 years old. SARD prevalence in women over 45 was close to 1%. Overall sensitivity was poor, but estimates for each of the 3 case definitions improved within older populations and were slightly higher for men compared to women.
  
  
  CONCLUSIONS
  Our results are consistent with previous estimates and other North American findings, and provide results from coast to coast, as well as useful information about the degree of regional and demographic variations that can be seen within a single country. Our work demonstrates the usefulness of using multiple data sources, adjusting for the error in each, and providing estimates of the sensitivity of different case definition approaches.
authors.affiliation: From the Division of Clinical Epidemiology, and Divisions of Rheumatology, and Clinical Immunology/Allergy, Research Institute of the McGill University Health Centre (MUHC), Montreal, Quebec; Division of Rheumatology, University of British Columbia, Vancouver, British Columbia; Department of Epidemiology and Biostatistics, and Division of Rheumatology, McGill University; Dalhousie University and Queen Elizabeth II Health Sciences Center, Halifax, Nova Scotia; Departments of Medicine and Community Health Sciences, University of Manitoba, and Repository, Manitoba Centre for Health Policy, Winnipeg, Manitoba; Centre for Chronic Disease Prevention, Public Health Agency of Canada, Ottawa, Ontario; Division of Rheumatology, University of Calgary, Calgary, Alberta; Centre de recherche du CHU de Québec, Faculté de médecine, Université Laval, Quebec City, Quebec; Chronic Disease Surveillance Division, National Institute of Public Health of Québec; Health Surveillance Branch, Public Health Division, Alberta Health and Wellness, Edmonton, Alberta; Divisions of Rheumatology, and Clinical Immunology/Allergy, Research Institute of the MUHC; Canadian Arthritis Patient Alliance; Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada.
authors.forename: Laurel
authors.initials: L
authors.lastname: Broten
authors.forename: J Antonio
authors.initials: JA
authors.lastname: Aviña-Zubieta
authors.forename: Diane
authors.initials: D
authors.lastname: Lacaille
authors.forename: Lawrence
authors.initials: L
authors.lastname: Joseph
authors.forename: John G
authors.initials: JG
authors.lastname: Hanly
authors.forename: Lisa
authors.initials: L
authors.lastname: Lix
authors.forename: Siobhan
authors.initials: S
authors.lastname: O'Donnell
authors.forename: Cheryl
authors.initials: C
authors.lastname: Barnabe
authors.forename: Paul R
authors.initials: PR
authors.lastname: Fortin
authors.forename: Marie
authors.initials: M
authors.lastname: Hudson
authors.forename: Sonia
authors.initials: S
authors.lastname: Jean
authors.forename: Christine
authors.initials: C
authors.lastname: Peschken
authors.forename: Steven M
authors.initials: SM
authors.lastname: Edworthy
authors.forename: Larry
authors.initials: L
authors.lastname: Svenson
authors.forename: Christian A
authors.initials: CA
authors.lastname: Pineau
authors.forename: Ann E
authors.initials: AE
authors.lastname: Clarke
authors.forename: Mark
authors.initials: M
authors.lastname: Smith
authors.forename: Patrick
authors.initials: P
authors.lastname: Bélisle
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Badley
authors.forename: Louise
authors.initials: L
authors.lastname: Bergeron
authors.forename: Sasha
authors.initials: S
authors.lastname: Bernatsky
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D001327:Autoimmune Diseases / Q000175:diagnosis / Q000453:epidemiology; D001499:Bayes Theorem; D002170:Canada / Q000453:epidemiology; D015897:Comorbidity; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012216:Rheumatic Diseases / Q000175:diagnosis / Q000453:epidemiology*; D012424:Rural Population; D012595:Scleroderma, Systemic / Q000175:diagnosis / Q000453:epidemiology*; D017678:Sex Distribution; D012859:Sjogren's Syndrome / Q000175:diagnosis / Q000453:epidemiology*; D014505:Urban Population
keywords: AUTOIMMUNE DISEASES; PREVALENCE; RHEUMATIC DISEASES; SYSTEMIC LUPUS ERYTHEMATOSUS; SYSTEMIC SCLEROSIS