title: Higher incidence of rheumatoid arthritis in patients with symptomatic osteoarthritis or osteoarthritis-related surgery: a nationwide, population-based, case-control study in Taiwan.
abstract: OBJECTIVE
  To investigate the risk of incident rheumatoid arthritis in patients with symptomatic osteoarthritis or osteoarthritis-related surgery using a nationwide health claims database.
  
  
  METHODS
  A nationwide, population-based, case-control study.
  
  
  METHODS
  Taiwan's National Health Insurance Research Database.
  
  
  METHODS
  A total of 1147 patients (aged 20-100 years) with rheumatoid arthritis and 5735 controls who were frequency-matched for sex, 10-year age interval and year of catastrophic illness certificate application date (index year) were identified.
  
  
  METHODS
  All participants were retrospectively traced, up to 14 years prior to their index year, for diagnosis of osteoarthritis or osteoarthritis-related surgery. Multivariate logistic regression analyses were conducted to quantify the association between rheumatoid arthritis and osteoarthritis.
  
  
  RESULTS
  The risks of rheumatoid arthritis were significantly higher in patients with symptomatic osteoarthritis (adjusted OR=5.24, p<0.001) and osteoarthritis-related surgery (adjusted OR=2.27, p<0.001).
  
  
  CONCLUSIONS
  This large nationwide, population-based, case-control study showed a higher risk of rheumatoid arthritis in Taiwanese patients with symptomatic osteoarthritis. Our findings were consistent with the hypothesis that osteoarthritis might be a triggering factor of rheumatoid arthritis in environment-sensitised and genetically susceptible individuals.
authors.affiliation: Division of Allergy, Immunology and Rheumatology, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan School of Medicine, Tzu Chi University, Hualien, Taiwan.
authors.forename: Ming-Chi
authors.initials: MC
authors.lastname: Lu
authors.affiliation: Department of Orthopedics, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.
authors.forename: Keng-Chang
authors.initials: KC
authors.lastname: Liu
authors.affiliation: Division of Allergy, Immunology and Rheumatology, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan School of Medicine, Tzu Chi University, Hualien, Taiwan.
authors.forename: Ning-Sheng
authors.initials: NS
authors.lastname: Lai
authors.affiliation: Department of Medical Research, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Malcolm
authors.identifier: http://orcid.org/0000-0002-9242-9167
authors.initials: M
authors.lastname: Koo
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000453:epidemiology* / Q000209:etiology*; D016022:Case-Control Studies; D016208:Databases, Factual; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000150:complications* / Q000453:epidemiology* / Q000601:surgery; D011159:Population Surveillance; D016016:Proportional Hazards Models; D012107:Research Design; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D017678:Sex Distribution; D013624:Taiwan / Q000453:epidemiology
keywords: GERIATRIC MEDICINE; RHEUMATOLOGY