title: Leflunomide-induced interstitial lung disease: prevalence and risk factors in Japanese patients with rheumatoid arthritis.
abstract: OBJECTIVE
  The possible link between LEF and interstitial lung disease (ILD) has evoked increasing concern. The aim of the present study was to elucidate the prevalence and risk factors for newly developed and/or exacerbated ILD, based on post-marketing surveillance data, in which all RA patients receiving LEF were pre-registered and monitored for 24 weeks in Japan.
  
  
  METHODS
  We analysed data from a cohort of 5054 RA patients who were prescribed LEF since its launch in September 2003 in Japan. Multivariable logistic analysis was performed to identify the risk factors for newly developed and/or exacerbation of ILD.
  
  
  RESULTS
  Sixty-one (1.2%) of 5054 RA patients who received LEF were reported to have development and/or exacerbation of ILD as an adverse drug reaction to LEF, judged by the attending physicians. Multivariable logistic regression analysis identified pre-existing ILD [odds ratio (OR) 8.17; 95% CI 4.63, 14.4], cigarette smoking (3.12; 95% CI 1.73, 5.60), a low body weight (<40 kg vs >50 kg) (2.91; 95% CI 1.15, 7.37) and the use of a loading dose (3.97; 95% CI 1.22, 12.9) as independent risk factors for LEF-induced ILD.
  
  
  CONCLUSIONS
  Pre-existing ILD was the most important risk factor for LEF-induced ILD. We suggest that LEF should not be prescribed for RA patients complicated with ILD.
authors.affiliation: Department of Rheumatology, Tokyo Medical University Hospital, Tokyo, Japan.
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Sawada
authors.forename: Shigeko
authors.initials: S
authors.lastname: Inokuma
authors.forename: Takeo
authors.initials: T
authors.lastname: Sato
authors.forename: Takeshi
authors.initials: T
authors.lastname: Otsuka
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Saeki
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Takeuchi
authors.forename: Takemasa
authors.initials: T
authors.lastname: Matsuda
authors.forename: Tamiko
authors.initials: T
authors.lastname: Takemura
authors.forename: Akira
authors.initials: A
authors.lastname: Sagawa