title: Acute exacerbation in rheumatoid arthritis-associated interstitial lung disease: a retrospective case control study.
abstract: OBJECTIVE
  To investigate the risk factors and prognosis associated with acute exacerbation (AE) in patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD).
  
  
  METHODS
  A retrospective case-control study.
  
  
  METHODS
  A single academic hospital.
  
  
  METHODS
  51 consecutive patients diagnosed with RA-ILD between 1995 and 2012. All patients fulfilled the diagnostic criteria of the American College of Rheumatology for RA. ILD was diagnosed on the basis of clinical presentation, pulmonary function tests, high-resolution CT (HRCT) findings and lung biopsy findings.
  
  
  METHODS
  Overall survival and cumulative AE incidence were analysed using Kaplan-Meier method. Cox hazards analysis was used to determine significant variables associated with AE occurrence and survival status.
  
  
  RESULTS
  A total of 11 patients (22%) developed AE, with an overall 1-year incidence of 2.8%. Univariate analysis revealed that older age at ILD diagnosis (HR 1.11; 95% CI 1.02 to 1.21; p=0.01), usual interstitial pneumonia (UIP) pattern on HRCT (HR 1.95; 95% CI 1.07 to 3.63; p=0.03) and methotrexate usage (HR 3.04; 95% CI 1.62 to 6.02; p=0.001) were associated with AE. Of 11 patients who developed AE during observation period, 7 (64%) died of initial AE. In survival, AE was a prognostic factor for poor outcome (HR 2.47; 95% CI 1.39 to 4.56; p=0.003).
  
  
  CONCLUSIONS
  In patients with RA-ILD, older age at ILD diagnosis, UIP pattern on HRCT and methotrexate usage are associated with the development of AE. Furthermore, AE has a serious impact on their survival.
authors.affiliation: Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan.
authors.forename: Hironao
authors.initials: H
authors.lastname: Hozumi
authors.forename: Yutaro
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Johkoh
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Sumikawa
authors.forename: Thomas V
authors.initials: TV
authors.lastname: Colby
authors.forename: Masato
authors.initials: M
authors.lastname: Kono
authors.forename: Dai
authors.initials: D
authors.lastname: Hashimoto
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Enomoto
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Fujisawa
authors.forename: Naoki
authors.initials: N
authors.lastname: Inui
authors.forename: Takafumi
authors.initials: T
authors.lastname: Suda
authors.forename: Kingo
authors.initials: K
authors.lastname: Chida
keywords: Rheumatology
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