title: Clinical features of organizing pneumonia associated with rheumatoid arthritis.
abstract: OBJECTIVE
  To clarify the clinical features of organizing pneumonia (OP) associated with rheumatoid arthritis (RA) and to determine whether development of OP is related to RA activity.
  
  
  METHODS
  A cross-sectional study was conducted, in which medical records of 499 consecutive RA patients who visited our hospital during one month were reviewed. OP was diagnosed by pathological findings by trans-bronchial biopsy or by clinical features (typical computed tomography findings, no causative agents, good response to glucocorticoids, and lack of response to antibiotics).
  
  
  RESULTS
  Among 499 patients, OP was found in 19 patients and the estimated prevalence was 1.9-4.8%. No differences in clinical features were noted between the OP and non-OP groups. The mean age of OP development was 57.2 years and the period from the onset of RA to OP ranged from -4 to +34 years. Although 14 patients presented OP after the onset of RA, two developed OP before RA and three developed OP simultaneously with RA. Patients receiving tumor necrosis factor inhibitors also developed OP. RA disease activity just before onset of OP was low in 8 of 14 RA cases. At the onset of OP, only two patients showed exacerbations of arthritis, whereas most patients presented with fever and serum C-reactive protein (CRP) elevations. Glucocorticoids were effective for OP in all patients who received them. Relapse occurred in 4 of 19 cases.
  
  
  CONCLUSIONS
  OP develops in approximately 4% of RA patients, which occurs independently from arthritis activity and at any time in RA patients.
authors.affiliation: a Pulmonary Medicine and Clinical Immunology , Dokkyo Medical University , Tochigi , Japan and.
authors.forename: Harutsugu
authors.initials: H
authors.lastname: Okada
authors.affiliation: a Pulmonary Medicine and Clinical Immunology , Dokkyo Medical University , Tochigi , Japan and.|b Center for Rheumatic Diseases , Dokkyo Medical University , Tochigi , Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kurasawa
authors.affiliation: a Pulmonary Medicine and Clinical Immunology , Dokkyo Medical University , Tochigi , Japan and.
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Yamazaki
authors.affiliation: a Pulmonary Medicine and Clinical Immunology , Dokkyo Medical University , Tochigi , Japan and.
authors.forename: Ayae
authors.initials: A
authors.lastname: Tanaka
authors.affiliation: a Pulmonary Medicine and Clinical Immunology , Dokkyo Medical University , Tochigi , Japan and.
authors.forename: Satoko
authors.initials: S
authors.lastname: Arai
authors.affiliation: a Pulmonary Medicine and Clinical Immunology , Dokkyo Medical University , Tochigi , Japan and.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Owada
authors.affiliation: a Pulmonary Medicine and Clinical Immunology , Dokkyo Medical University , Tochigi , Japan and.|b Center for Rheumatic Diseases , Dokkyo Medical University , Tochigi , Japan.
authors.forename: Reika
authors.initials: R
authors.lastname: Maezawa
authors.affiliation: a Pulmonary Medicine and Clinical Immunology , Dokkyo Medical University , Tochigi , Japan and.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Ishii
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications*; D001706:Biopsy; D002097:C-Reactive Protein; D003430:Cross-Sectional Studies; D018549:Cryptogenic Organizing Pneumonia / Q000188:drug therapy / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012008:Recurrence; D016896:Treatment Outcome
chemical_list: D005938:Glucocorticoids; D002097:C-Reactive Protein
keywords: Disease activity; Organizing pneumonia; Prevalence; Pulmonary diseases; Rheumatoid arthritis