title: Risk of rheumatoid arthritis in patients with type 2 diabetes: a nationwide population-based case-control study.
abstract: OBJECTIVE
  Type 2 diabetes is associated with chronic, low-grade inflammation and could potentially trigger the progression of other, more prominent inflammatory diseases such as rheumatoid arthritis (RA). Therefore, we aimed to investigate the risk of incident RA in Taiwanese patients with type 2 diabetes using a population-based health claims database.
  
  
  METHODS
  This nationwide, population-based, case-control study used administrative data to identify 1,416 patients with RA (age ≥20 years) as cases and 7,080 controls that were frequency-matched for sex, 10-year age group, and year of catastrophic illness certificate application date (index year). All subjects were retrospectively traced back, up to 13 years prior to the index year, for their first diagnosis of type 2 diabetes. Logistic regression analysis was conducted to quantify the association between incident RA and type 2 diabetes.
  
  
  RESULTS
  The odds of developing RA were significantly higher in female (odds ratio [OR] 1.46, 95% confidence interval [95% CI] 1.24-1.72) but not in male (OR 1.00, 95% CI 0.72-1.37) patients who had previously diagnosed with type 2 diabetes. Subgroup analysis indicated that the odds of developing RA were more prominent in younger females (20 to 44 years of age) with type 2 diabetes. In addition, the odds of developing RA in female patients with type 2 diabetes were higher in those with a shorter time interval between the diagnosis of type 2 diabetes and RA.
  
  
  CONCLUSIONS
  This large nationwide, population-based, case-control study showed an elevated risk of RA in female Taiwanese patients with type 2 diabetes. Our findings were consistent with the hypothesis that chronic low-grade inflammation in type 2 diabetes may elicit the development of RA in 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: Division of Endocrinology and Metabolism, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.
authors.forename: Shih-Tang
authors.initials: ST
authors.lastname: Yan
authors.affiliation: School of Medicine, Tzu Chi University, Hualien, Taiwan; Division of General Surgery, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan.
authors.forename: Wen-Yao
authors.initials: WY
authors.lastname: Yin
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, Ontario, Canada.
authors.forename: Malcolm
authors.initials: M
authors.lastname: Koo
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
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000453:epidemiology*; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult